History log of /freebsd-10.3-release/sys/i386/i386/machdep.c
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# 296373 04-Mar-2016 marius

- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

# 294683 24-Jan-2016 ian

MFC r293045, r293046:

Make the 'env' directive described in config(5) work on all architectures,
providing compiled-in static environment data that is used instead of any
data passed in from a boot loader.

Previously 'env' worked only on i386 and arm xscale systems, because it
required the MD startup code to examine the global envmode variable and
decide whether to use static_env or an environment obtained from the boot
loader, and set the global kern_envp accordingly. Most startup code wasn't
doing so. Making things even more complex, some mips startup code uses an
alternate scheme that involves calling init_static_kenv() to pass an empty
buffer and its size, then uses a series of kern_setenv() calls to populate
that buffer.

Now all MD startup code calls init_static_kenv(), and that routine provides
a single point where envmode is checked and the decision is made whether to
use the compiled-in static_kenv or the values provided by the MD code.

The routine also continues to serve its original purpose for mips; if a
non-zero buffer size is passed the routine installs the empty buffer ready
to accept kern_setenv() values. Now if the size is zero, the provided buffer
full of existing env data is installed. A NULL pointer can be passed if the
boot loader provides no env data; this allows the static env to be installed
if envmode is set to do so.

Most of the work here is a near-mechanical change to call the init function
instead of directly setting kern_envp. A notable exception is in xen/pv.c;
that code was originally installing a buffer full of preformatted env data
along with its non-zero size (like mips code does), which would have allowed
kern_setenv() calls to wipe out the preformatted data. Now it passes a zero
for the size so that the buffer of data it installs is treated as
non-writeable.

Also, revert accidental change that snuck into r293045.


# 293581 09-Jan-2016 dchagin

MFC r283479:

The kernel sends signals to the processes via ABI specific sv_sendsig method.
Native ABI do not need signal conversion, only emulators may want this. Usually
emulators implements its own sv_sendsig method. For now only ibcs2 emulator does
not have own sv_sendsig implementation and depends on native sendsig() method.
So, remove any extra attempts to convert signal numbers from native sendsig()
methods except from i386 where ibsc2 is living.


# 290734 13-Nov-2015 jhb

MFC 284325:
Report the values of x86 segment registers to remote debuggers.

While here, also report %eflags from the i386 trapframe.


# 290731 13-Nov-2015 jhb

MFC 285783:
Various changes to the registers displayed in DDB for x86.
- Fix segment registers to only display the low 16 bits.
- Remove unused handlers and entries for the debug registers.
- Display xcr0 (if valid) in 'show sysregs'.
- Add '0x' prefix to MSR values to match other values in 'show sysregs'.
- MFamd64: Display various MSRs in 'show sysregs'.
- Add a 'show dbregs' to display the value of debug registers.
- Dynamically size the column width for register values to properly
align columns on 64-bit platforms.
- Display %gs for i386 in 'show registers'.


# 287126 25-Aug-2015 marcel

MFC r286667 & r286723

Better support memory mapped console devices, such as VGA and EFI
frame buffers and memory mapped UARTs.

PR: 191564, 194952, 202276


# 286878 18-Aug-2015 kib

MFC r286288:
Give large kernel stack to the initial thread.


# 282066 27-Apr-2015 kib

MFC r281762:
Remove duplicate definitions of MWAIT_CX hints. Identical defines in
specialreg.h are enough.


# 282065 27-Apr-2015 kib

MFC r281495:
Add config option PAE_TABLES for the i386 kernel. It switches pmap to
use PAE format for the page tables, but does not incur other
consequences of the full PAE config. In particular, vm_paddr_t and
bus_addr_t are left 32bit, and max supported memory is still limited
by 4GB.

The option allows to have nx permissions for memory mappings on i386
kernel, while keeping the usual i386 KBI and avoiding the kernel data
sizing problems typical for the PAE config.


# 280973 02-Apr-2015 jhb

MFC 276724:
On some Intel CPUs with a P-state but not C-state invariant TSC the TSC
may also halt in C2 and not just C3 (it seems that in some cases the BIOS
advertises its C3 state as a C2 state in _CST). Just play it safe and
disable both C2 and C3 states if a user forces the use of the TSC as the
timecounter on such CPUs.

PR: 192316


# 278347 07-Feb-2015 kib

MFC r278001:
Do not qualify the mcontext_t *mcp argument for set_mcontext(9) as const.


# 276135 23-Dec-2014 nyan

MFC: r272492

Merge pc98's machdep.c into i386/i386/machdep.c.


# 276085 22-Dec-2014 jhb

MFC 275035:
MFamd64: Check for invalid flags in the machine context in sigreturn()
and setcontext().


# 276084 22-Dec-2014 jhb

MFC 273988,273989,273995,274057:
MFamd64: Add support for extended FPU states on i386. This includes
support for AVX on i386.


# 276076 22-Dec-2014 jhb

MFC 271405,271408,271409,272658:
MFamd64: Use initializecpu() to set various model-specific registers on
AP startup and AP resume (it was already used for BSP startup and BSP
resume).


# 276070 22-Dec-2014 jhb

MFC 260557,271076,271077,271082,271083,271098:
- Remove spaces from boot messages when we print the CPU ID/Family/Stepping
- Move prototypes for various functions into out of C files and into
<machine/md_var.h>.
- Reduce diffs between i386 and amd64 initcpu.c and identcpu.c files.
- Move blacklists of broken TSCs out of the printcpuinfo() function
and into the TSC probe routine.
- Merge the amd64 and i386 identcpu.c into a single x86 implementation.


# 275921 18-Dec-2014 jhb

MFC 273871:
Skip the smap sysctl instead of panicing if no kernel metadata can be
found.


# 272913 10-Oct-2014 jhb

MFC 270828,271487,271495:
Add sysctls to export the BIOS SMAP and EFI memory maps along with
handlers in the sysctl(8) binary to format them.


# 271541 13-Sep-2014 pfg

MFC r271149:
Apply known workarounds for less modern MacBooks.

The legacy USB circuit tends to give trouble on older MacBooks.
While the original report covered MacBook4, extend the fix
preemptively for the newer MacBookPro4 too.

PR: 191693
Reviewed by: emaste
Approved by: re


# 271191 06-Sep-2014 jhb

MFC 270826:
MFamd64: Add a machdep.bootmethod sysctl to inform the installer which
firmware method was used for booting. This is hardcoded to BIOS on i386.

PR: 192962
Approved by: re (gjb)


# 267964 27-Jun-2014 jhb

MFC 261781:
Don't waste a page of KVA for the boot-time memory test on x86. For amd64,
reuse the first page of the crashdumpmap as CMAP1/CADDR1. For i386,
remove CMAP1/CADDR1 entirely and reuse CMAP3/CADDR3 for the memory test.


# 258996 05-Dec-2013 royger

MFC 258176:

Fix accounting for hw.realmem on the i386 and amd64 platforms.

sys/i386/i386/machdep.c:
sys/amd64/amd64/machdep.c:
The value reported by FreeBSD as "real memory" when booting
doesn't match what is later reported by sysctl as hw.realmem.
This is due to the fact that the value printed during the
boot process is fetched from smbios data (when possible),
and accounts for holes in physical memory. On the other
hand, the value of hw.realmem is unconditionally set to be
one larger than the highest page of the physical address
space.

Fix this by setting hw.realmem to the same value printed
during boot, this makes hw.realmem honour it's name and
account properly for physical memory present in the system.

Submitted by: Roger Pau Monné
Reviewed by: gibbs
Approved by: gibbs (mentor)
Approved by: re (gjb)


# 258559 25-Nov-2013 emaste

MFC r258135: x86: Allow users to change PSL_RF via ptrace(PT_SETREGS...)

Debuggers may need to change PSL_RF. Note that tf_eflags is already stored
in the signal context during signal handling and PSL_RF previously could
be modified via sigreturn, so this change should not provide any new
ability to userspace.

For background see the thread at:
http://lists.freebsd.org/pipermail/freebsd-i386/2007-September/005910.html

Reviewed by: jhb, kib

Sponsored by: DARPA, AFRL
Approved by: re (gjb)


# 258158 15-Nov-2013 kib

MFC r257858:
Fix signal delivery for the iBCS2 binaries.

Approved by: re (gjb)


# 256281 10-Oct-2013 gjb

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation


# 255040 29-Aug-2013 gibbs

Implement vector callback for PVHVM and unify event channel implementations

Re-structure Xen HVM support so that:
- Xen is detected and hypercalls can be performed very
early in system startup.
- Xen interrupt services are implemented using FreeBSD's native
interrupt delivery infrastructure.
- the Xen interrupt service implementation is shared between PV
and HVM guests.
- Xen interrupt handlers can optionally use a filter handler
in order to avoid the overhead of dispatch to an interrupt
thread.
- interrupt load can be distributed among all available CPUs.
- the overhead of accessing the emulated local and I/O apics
on HVM is removed for event channel port events.
- a similar optimization can eventually, and fairly easily,
be used to optimize MSI.

Early Xen detection, HVM refactoring, PVHVM interrupt infrastructure,
and misc Xen cleanups:

Sponsored by: Spectra Logic Corporation

Unification of PV & HVM interrupt infrastructure, bug fixes,
and misc Xen cleanups:

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D

sys/x86/x86/local_apic.c:
sys/amd64/include/apicvar.h:
sys/i386/include/apicvar.h:
sys/amd64/amd64/apic_vector.S:
sys/i386/i386/apic_vector.s:
sys/amd64/amd64/machdep.c:
sys/i386/i386/machdep.c:
sys/i386/xen/exception.s:
sys/x86/include/segments.h:
Reserve IDT vector 0x93 for the Xen event channel upcall
interrupt handler. On Hypervisors that support the direct
vector callback feature, we can request that this vector be
called directly by an injected HVM interrupt event, instead
of a simulated PCI interrupt on the Xen platform PCI device.
This avoids all of the overhead of dealing with the emulated
I/O APIC and local APIC. It also means that the Hypervisor
can inject these events on any CPU, allowing upcalls for
different ports to be handled in parallel.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
Map Xen per-vcpu area during AP startup.

sys/amd64/include/intr_machdep.h:
sys/i386/include/intr_machdep.h:
Increase the FreeBSD IRQ vector table to include space
for event channel interrupt sources.

sys/amd64/include/pcpu.h:
sys/i386/include/pcpu.h:
Remove Xen HVM per-cpu variable data. These fields are now
allocated via the dynamic per-cpu scheme. See xen_intr.c
for details.

sys/amd64/include/xen/hypercall.h:
sys/dev/xen/blkback/blkback.c:
sys/i386/include/xen/xenvar.h:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/xen/gnttab.c:
Prefer FreeBSD primatives to Linux ones in Xen support code.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
sys/dev/xen/balloon/balloon.c:
sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/console/xencons_ring.c:
sys/dev/xen/control/control.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/xenpci/xenpci.c:
sys/i386/i386/machdep.c:
sys/i386/include/pmap.h:
sys/i386/include/xen/xenfunc.h:
sys/i386/isa/npx.c:
sys/i386/xen/clock.c:
sys/i386/xen/mp_machdep.c:
sys/i386/xen/mptable.c:
sys/i386/xen/xen_clock_util.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/xen_rtc.c:
sys/xen/evtchn/evtchn_dev.c:
sys/xen/features.c:
sys/xen/gnttab.c:
sys/xen/gnttab.h:
sys/xen/hvm.h:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_if.m:
sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusvar.h:
sys/xen/xenstore/xenstore.c:
sys/xen/xenstore/xenstore_dev.c:
sys/xen/xenstore/xenstorevar.h:
Pull common Xen OS support functions/settings into xen/xen-os.h.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
Remove constants, macros, and functions unused in FreeBSD's Xen
support.

sys/xen/xen-os.h:
sys/i386/xen/xen_machdep.c:
sys/x86/xen/hvm.c:
Introduce new functions xen_domain(), xen_pv_domain(), and
xen_hvm_domain(). These are used in favor of #ifdefs so that
FreeBSD can dynamically detect and adapt to the presence of
a hypervisor. The goal is to have an HVM optimized GENERIC,
but more is necessary before this is possible.

sys/amd64/amd64/machdep.c:
sys/dev/xen/xenpci/xenpcivar.h:
sys/dev/xen/xenpci/xenpci.c:
sys/x86/xen/hvm.c:
sys/sys/kernel.h:
Refactor magic ioport, Hypercall table and Hypervisor shared
information page setup, and move it to a dedicated HVM support
module.

HVM mode initialization is now triggered during the
SI_SUB_HYPERVISOR phase of system startup. This currently
occurs just after the kernel VM is fully setup which is
just enough infrastructure to allow the hypercall table
and shared info page to be properly mapped.

sys/xen/hvm.h:
sys/x86/xen/hvm.c:
Add definitions and a method for configuring Hypervisor event
delievery via a direct vector callback.

sys/amd64/include/xen/xen-os.h:
sys/x86/xen/hvm.c:

sys/conf/files:
sys/conf/files.amd64:
sys/conf/files.i386:
Adjust kernel build to reflect the refactoring of early
Xen startup code and Xen interrupt services.

sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
sys/dev/xen/control/control.c:
sys/dev/xen/evtchn/evtchn_dev.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/xen/xenstore/xenstore.c:
sys/xen/evtchn/evtchn_dev.c:
sys/dev/xen/console/console.c:
sys/dev/xen/console/xencons_ring.c
Adjust drivers to use new xen_intr_*() API.

sys/dev/xen/blkback/blkback.c:
Since blkback defers all event handling to a taskqueue,
convert this task queue to a "fast" taskqueue, and schedule
it via an interrupt filter. This avoids an unnecessary
ithread context switch.

sys/xen/xenstore/xenstore.c:
The xenstore driver is MPSAFE. Indicate as much when
registering its interrupt handler.

sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbusvar.h:
Remove unused event channel APIs.

sys/xen/evtchn.h:
Remove all kernel Xen interrupt service API definitions
from this file. It is now only used for structure and
ioctl definitions related to the event channel userland
device driver.

Update the definitions in this file to match those from
NetBSD. Implementing this interface will be necessary for
Dom0 support.

sys/xen/evtchn/evtchnvar.h:
Add a header file for implemenation internal APIs related
to managing event channels event delivery. This is used
to allow, for example, the event channel userland device
driver to access low-level routines that typical kernel
consumers of event channel services should never access.

sys/xen/interface/event_channel.h:
sys/xen/xen_intr.h:
Standardize on the evtchn_port_t type for referring to
an event channel port id. In order to prevent low-level
event channel APIs from leaking to kernel consumers who
should not have access to this data, the type is defined
twice: Once in the Xen provided event_channel.h, and again
in xen/xen_intr.h. The double declaration is protected by
__XEN_EVTCHN_PORT_DEFINED__ to ensure it is never declared
twice within a given compilation unit.

sys/xen/xen_intr.h:
sys/xen/evtchn/evtchn.c:
sys/x86/xen/xen_intr.c:
sys/dev/xen/xenpci/evtchn.c:
sys/dev/xen/xenpci/xenpcivar.h:
New implementation of Xen interrupt services. This is
similar in many respects to the i386 PV implementation with
the exception that events for bound to event channel ports
(i.e. not IPI, virtual IRQ, or physical IRQ) are further
optimized to avoid mask/unmask operations that aren't
necessary for these edge triggered events.

Stubs exist for supporting physical IRQ binding, but will
need additional work before this implementation can be
fully shared between PV and HVM.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
sys/i386/xen/mp_machdep.c
sys/x86/xen/hvm.c:
Add support for placing vcpu_info into an arbritary memory
page instead of using HYPERVISOR_shared_info->vcpu_info.
This allows the creation of domains with more than 32 vcpus.

sys/i386/i386/machdep.c:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/exception.s:
Add support for new event channle implementation.


# 254619 21-Aug-2013 jkim

Reimplement atomic_load_acq_64() and atomic_store_rel_64() for i386. These
functions are now real functions rather than function pointers. Supposedly,
it is faster for modern processors.

Suggested by: bde


# 254384 15-Aug-2013 jkim

Simplify check for CMPXCHG8B instruction. Note CMPXCHG8B instruction is
always available for Rise mP6 processors although it is not set by CPUID.


# 254025 07-Aug-2013 jeff

Replace kernel virtual address space allocation with vmem. This provides
transparent layering and better fragmentation.

- Normalize functions that allocate memory to use kmem_*
- Those that allocate address space are named kva_*
- Those that operate on maps are named kmap_*
- Implement recursive allocation handling for kmem_arena in vmem.

Reviewed by: alc
Tested by: pho
Sponsored by: EMC / Isilon Storage Division


# 251039 27-May-2013 kib

Use slightly more idiomatic expression to get the address of array.

Tested by: dim, pgj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week


# 250840 21-May-2013 marcel

Add basic support for FDT to i386 & amd64. This change includes:
1. Common headers for fdt.h and ofw_machdep.h under x86/include
with indirections under i386/include and amd64/include.
2. New modinfo for loader provided FDT blob.
3. Common x86_init_fdt() called from hammer_time() on amd64 and
init386() on i386.
4. Split-off FDT specific low-level console functions from FDT
bus methods for the uart(4) driver. The low-level console
logic has been moved to uart_cpu_fdt.c and is used for arm,
mips & powerpc only. The FDT bus methods are shared across
all architectures.
5. Add dev/fdt/fdt_x86.c to hold the fdt_fixup_table[] and the
fdt_pic_table[] arrays. Both are empty right now.

FDT addresses are I/O ports on x86. Since the core FDT code does
not handle different address spaces, adding support for both I/O
ports and memory addresses requires some thought and discussion.
It may be better to use a compile-time option that controls this.

Obtained from: Juniper Networks, Inc.


# 248084 09-Mar-2013 attilio

Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
- VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
- VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
- VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
- VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
(in order to avoid visibility of implementation details)
- The read-mode operations are added:
VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
sys/mutex.h in consumers directly to cater its inlining functions
using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
the compat layer because the name clash between FreeBSD and solaris
versions must be avoided.
At this purpose zfs redefines the vm_object locking functions
directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit. Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by: EMC / Isilon storage division
Reviewed by: jeff
Reviewed by: pjd (ZFS specific review)
Discussed with: alc
Tested by: pho


# 247454 28-Feb-2013 davide

MFcalloutng:
When CPU becomes idle, cpu_idleclock() calculates time to the next timer
event in order to reprogram hw timer. Return that time in sbintime_t to
the caller and pass it to acpi_cpu_idle(), where it can be used as one
more factor (quite precise) to extimate furter sleep time and choose
optimal sleep state. This is a preparatory change for further callout
improvements will be committed in the next days.

The commmit is not targeted for MFC.


# 241880 22-Oct-2012 eadler

The 'testing memory' patch gets printed too many times

Approved by: cperciva (implicit)


# 241850 22-Oct-2012 eadler

Explain the upcoming delay by printing a message when the kernel
is about to begin testing memory.

Reviewed by: dteske, adri
Approved by: cperciva
MFC after: 1 week


# 241371 09-Oct-2012 attilio

Reverts r234074,234105,234564,234723,234989,235231-235232 and part of
r234247.
Use, instead, the static intializer introduced in r239923 for x86 and
sparc64 intr_cpus, unwinding the code to the initial version.

Reviewed by: marius


# 238792 26-Jul-2012 kib

MFamd64 r238623:
Introduce curpcb magic variable.

Requested and reviewed by: bde
MFC after: 3 weeks


# 238310 09-Jul-2012 jhb

Partially revert r217515 so that the mem_range_softc variable is always
present on x86 kernels. This fixes the build of kernels that include
'device acpi' but do not include 'device mem'.

MFC after: 1 month


# 237996 02-Jul-2012 brueffer

Fix XEN build, broken in r237924.

Reported by: gcooper
Pointy hat: brueffer


# 237924 01-Jul-2012 brueffer

Replace an unreachable panic() in vm86_getptr (been there for 13 years) with
a KASSERT() behind the functions's only consumer.

Suggested by: kib
Reviewed by: kib
CID: 4494
Found with: Coverity Prevent(tm)
MFC after: 2 weeks


# 237445 22-Jun-2012 kib

Commit changes missed from r237435. Properly calculate the signal
trampoline addresses after the shared page is enabled. Handle FreeBSD
ABIs without shared page support too.

Reported and tested by: David Wolfskill <david catwhisker org>
(previous version)
Pointy hat to: kib
MFC after: 1 month


# 235622 18-May-2012 iwasaki

Add SMP/i386 suspend/resume support.
Most part is merged from amd64.

- i386/acpica/acpi_wakecode.S
Replaced with amd64 code (from realmode to paging enabling code).

- i386/acpica/acpi_wakeup.c
Replaced with amd64 code (except for wakeup_pagetables stuff).

- i386/include/pcb.h
- i386/i386/genassym.c
Added PCB new members (CR0, CR2, CR4, DS, ED, FS, SS, GDT, IDT, LDT
and TR) needed for suspend/resume, not for context switch.

- i386/i386/swtch.s
Added suspendctx() and resumectx().
Note that savectx() was not changed and used for suspending (while
amd64 code uses it).
BSP and AP execute the same sequence, suspendctx(), acpi_wakecode()
and resumectx() for suspend/resume (in case of UP system also).

- i386/i386/apic_vector.s
Added cpususpend().

- i386/i386/mp_machdep.c
- i386/include/smp.h
Added cpususpend_handler().

- i386/include/apicvar.h
- kern/subr_smp.c
- sys/smp.h
Added IPI_SUSPEND and suspend_cpus().

- i386/i386/initcpu.c
- i386/i386/machdep.c
- i386/include/md_var.h
- pc98/pc98/machdep.c
Moved initializecpu() declarations to md_var.h.

MFC after: 3 days


# 234723 26-Apr-2012 attilio

Clean up the intr* MD KPI from the SMP dependency, removing a cause of
discrepancy between modules and kernel, but deal with SMP differences
within the functions themselves.

As an added bonus this also helps in terms of code readability.

Requested by: gibbs
Reviewed by: jhb, marius
MFC after: 1 week


# 234105 10-Apr-2012 marius

Fix !SMP build after r234074.

Reviewed by: attilio, jhb


# 234074 09-Apr-2012 attilio

BSP is not added to the mask of valid target CPUs for interrupts
in set_apic_interrupt_ids(). Besides, set_apic_interrupts_ids() is not
called in the !SMP case too.
Fix this by:
- Adding the BSP as an interrupt target directly in cpu_startup().
- Remove an obsolete optimization where the BSP are skipped in
set_apic_interrupt_ids().

Reported by: jh
Reviewed by: jhb
MFC after: 3 days
X-MFC: r233961
Pointy hat to: me


# 233031 16-Mar-2012 nyan

- Fix to build a native i386 kernel without the SMP and atpic.
- Merge r232744 changes to pc98.
(Allow a kernel to be built with 'nodevice atpic'.)
- Move ICU related defines from x86/isa/atpic.c to x86/isa/icu.h and
use them in x86/x86/intr_machdep.c.

Reviewed by: jhb


# 232744 09-Mar-2012 jhb

Allow a native i386 kernel to be built with 'nodevice atpic'. Just as on
amd64, if 'device isa' is present quiesce the 8259A's during boot and
resume from suspend.

While here, be more selective on amd64 about which kernel configurations
need elcr.c.

MFC after: 2 weeks


# 230426 21-Jan-2012 kib

Add support for the extended FPU states on amd64, both for native
64bit and 32bit ABIs. As a side-effect, it enables AVX on capable
CPUs.

In particular:

- Query the CPU support for XSAVE, list of the supported extensions
and the required size of FPU save area. The hw.use_xsave tunable is
provided for disabling XSAVE, and hw.xsave_mask may be used to
select the enabled extensions.

- Remove the FPU save area from PCB and dynamically allocate the
(run-time sized) user save area on the top of the kernel stack,
right above the PCB. Reorganize the thread0 PCB initialization to
postpone it after BSP is queried for save area size.

- The dumppcb, stoppcbs and susppcbs now do not carry the FPU state as
well. FPU state is only useful for suspend, where it is saved in
dynamically allocated suspfpusave area.

- Use XSAVE and XRSTOR to save/restore FPU state, if supported and
enabled.

- Define new mcontext_t flag _MC_HASFPXSTATE, indicating that
mcontext_t has a valid pointer to out-of-struct extended FPU
state. Signal handlers are supplied with stack-allocated fpu
state. The sigreturn(2) and setcontext(2) syscall honour the flag,
allowing the signal handlers to inspect and manipilate extended
state in the interrupted context.

- The getcontext(2) never returns extended state, since there is no
place in the fixed-sized mcontext_t to place variable-sized save
area. And, since mcontext_t is embedded into ucontext_t, makes it
impossible to fix in a reasonable way. Instead of extending
getcontext(2) syscall, provide a sysarch(2) facility to query
extended FPU state.

- Add ptrace(2) support for getting and setting extended state; while
there, implement missed PT_I386_{GET,SET}XMMREGS for 32bit binaries.

- Change fpu_kern KPI to not expose struct fpu_kern_ctx layout to
consumers, making it opaque. Internally, struct fpu_kern_ctx now
contains a space for the extended state. Convert in-kernel consumers
of fpu_kern KPI both on i386 and amd64.

First version of the support for AVX was submitted by Tim Bird
<tim.bird am sony com> on behalf of Sony. This version was written
from scratch.

Tested by: pho (previous version), Yamagi Burmeister <lists yamagi org>
MFC after: 1 month


# 229085 31-Dec-2011 gavin

Default to not performing the early-boot memory tests when we detect we
are booting inside a VM. There are three reasons to disable this:

o It causes the VM host to believe that all the tested pages or RAM are
in use. This in turn may force the host to page out pages of RAM
belonging to other VMs, or otherwise cause problems with fair resource
sharing on the VM cluster.
o It adds significant time to the boot process (around 1 second/Gig in
testing)
o It is unnecessary - the host should have already verified that the
memory is functional etc.

Note that this simply changes the default when in a VM - it can still be
overridden using the hw.memtest.tests tunable.

MFC after: 4 weeks


# 227442 11-Nov-2011 kib

Weaken the part of assertions added in the r227394. Only check that the
process state is stopped.

MFC after: 1 week


# 227394 09-Nov-2011 kib

Stopped process may legitimately have some threads sleeping and not
suspended, if the sleep is uninterruptible.

Reported and tested by: pho
MFC after: 1 week


# 225936 03-Oct-2011 attilio

Add some improvements in the idle table callbacks:
- Replace instances of manual assembly instruction "hlt" call
with halt() function calling.
- In cpu_idle_mwait() avoid races in check to sched_runnable() using
the same pattern used in cpu_idle_hlt() with the 'hlt' instruction.
- Add comments explaining the logic behind the pattern used in
cpu_idle_hlt() and other idle callbacks.

In collabouration with: jhb, mav
Reviewed by: adri, kib
MFC after: 3 weeks


# 225617 16-Sep-2011 kmacy

In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by: rwatson
Approved by: re (bz)


# 225048 20-Aug-2011 bz

In HEAD when doing no further checkes there is no reason use the
temporary variable and check with if as TUNABLE_*_FETCH do not
alter values unless successfully found the tunable.

Reported by: jhb, bde
MFC after: 3 days
X-MFC with: r224516
Approved by: re (kib)


# 224516 30-Jul-2011 bz

Introduce a tunable to disable the time consuming parts of bootup
memtesting, which can easily save seconds to minutes of boot time.
The tunable name is kept general to allow reusing the code in
alternate frameworks.

Requested by: many
Discussed on: arch (a while a go)
Obtained from: Sandvine Incorporated
Reviewed by: sbruno
Approved by: re (kib)
MFC after: 2 weeks


# 222853 08-Jun-2011 avg

remove code for dynamic offlining/onlining of CPUs on x86

The code has definitely been broken for SCHED_ULE, which is a default
scheduler. It may have been broken for SCHED_4BSD in more subtle ways,
e.g. with manually configured CPU affinities and for interrupt devilery
purposes.
We still provide a way to disable individual CPUs or all hyperthreading
"twin" CPUs before SMP startup. See the UPDATING entry for details.

Interaction between building CPU topology and disabling CPUs still
remains fuzzy: topology is first built using all availble CPUs and then
the disabled CPUs should be "subtracted" from it. That doesn't work
well if the resulting topology becomes non-uniform.

This work is done in cooperation with Attilio Rao who in addition to
reviewing also provided parts of code.

PR: kern/145385
Discussed with: gcooper, ambrisko, mdf, sbruno
Reviewed by: attilio
Tested by: pho, pluknet
X-MFC after: never


# 221835 13-May-2011 mav

Refactor Xen PV code to use new event timers subsystem. That uses one-shot
Xen timer and time counter to provide one-shot and periodic time events.

On my tests this reduces idle interruts rate down to about 30Hz, and accor-
ding to Xen VM Manager reduces host CPU load by three times comparing to
the previous periodic 100Hz clock. Also now, when needed, it is possible to
increase HZ rate without useless CPU burning during idle periods.

Now only ia64 and some ARMs left not migrated to the new event timers.


# 221599 07-May-2011 mav

Don't use MWAIT for short sleeps under XEN, as it was before r212541.
This fixes panic during boot in PV mode on Xen 3.2.


# 220584 13-Apr-2011 jkim

Reduce errors in effective frequency calculation.


# 220583 12-Apr-2011 jkim

Reinstate cpu_est_clockrate() support for P-state invariant TSC if APERF and
MPERF MSRs are available. It was disabled in r216443. Remove the earlier
hack to subtract 0.5% from the calibrated frequency as DELAY(9) is little
bit more reliable now.


# 220433 07-Apr-2011 jkim

Use atomic load & store for TSC frequency. It may be overkill for amd64 but
safer for i386 because it can be easily over 4 GHz now. More worse, it can
be easily changed by user with 'machdep.tsc_freq' tunable (directly) or
cpufreq(4) (indirectly). Note it is intentionally not used in performance
critical paths to avoid performance regression (but we should, in theory).
Alternatively, we may add "virtual TSC" with lower frequency if maximum
frequency overflows 32 bits (and ignore possible incoherency as we do now).


# 220404 07-Apr-2011 jkim

Implement atomic_load_acq_64(9) and atomic_store_rel_64(9) for i386. These
functions are implemented with CMPXCHG8B instruction where it is available,
i. e., all Pentium-class and later processors. Note this instruction is
also used for atomic_store_rel_64() because a simple XCHG-like instruction
for 64-bit memory access does not exist, unfortunately. If the processor
lacks the instruction, i. e., 80486-class CPUs, two 32-bit load/store are
performed with interrupt temporarily disabled, assuming it does not support
SMP. Although this assumption may be little naive, it is true in reality.
This implementation is inspired by Linux.


# 219673 15-Mar-2011 jkim

Deprecate tsc_present as the last of its real consumers finally disappeared.


# 219473 11-Mar-2011 jkim

Add a tunable "machdep.disable_tsc" to turn off TSC. Specifically, it turns
off boot-time CPU frequency calibration, DELAY(9) with TSC, and using TSC as
a CPU ticker. Note tsc_present does not change by this tunable.


# 219461 10-Mar-2011 jkim

Deprecate rarely used tsc_is_broken. Instead, we zero out tsc_freq because
it is almost always used with tsc_freq any way.


# 218744 16-Feb-2011 dchagin

To avoid excessive code duplication create wrapper for fill regs
from stack frame. Change the trap() code to use newly created function
instead of explicit regs assignment.


# 218329 05-Feb-2011 kib

Fix linking of the kernel without device npx.

MFC after: 2 weeks


# 218327 05-Feb-2011 kib

Clear the padding when returning context to the usermode, for
MI ucontext_t and x86 MD parts.
Kernel allocates the structures on the stack, and not clearing
reserved fields and paddings causes leakage.

Noted and discussed with: bde
MFC after: 2 weeks


# 217886 26-Jan-2011 mdf

Set td_kstack_pages for thread0. This was already being done for most
architectures, but i386 and amd64 were missing it.

Submitted by: Mohd Fahadullah <mfahadullah AT isilon DOT com>


# 217688 21-Jan-2011 pluknet

Make MSGBUF_SIZE kernel option a loader tunable kern.msgbufsize.

Submitted by: perryh pluto.rain.com (previous version)
Reviewed by: jhb
Approved by: kib (mentor)
Tested by: universe


# 217515 17-Jan-2011 jkim

Add reader/writer lock around mem_range_attr_get() and mem_range_attr_set().
Compile sys/dev/mem/memutil.c for all supported platforms and remove now
unnecessary dev_mem_md_init(). Consistently define mem_range_softc from
mem.c for all platforms. Add missing #include guards for machine/memdev.h
and sys/memrange.h. Clean up some nearby style(9) nits.

MFC after: 1 month


# 216443 14-Dec-2010 jkim

Stop lying about supporting cpu_est_clockrate() when TSC is invariant. This
function always returned the nominal frequency instead of current frequency
because we use RDTSC instruction to calculate difference in CPU ticks, which
is supposedly constant for the case. Now we support cpu_get_nominal_mhz()
for the case, instead. Note it should be just enough for most usage cases
because cpu_est_clockrate() is often times abused to find maximum frequency
of the processor.


# 216312 08-Dec-2010 jkim

Do not subtract 0.5% from estimated frequency if DELAY(9) is driven by TSC.
Remove a confusing comment about converting to MHz as we never did.


# 216041 29-Nov-2010 cperciva

Fix bug introduced by r194784: Under XEN, the page(s) allocated to dpcpu
for CPU #0 weren't being properly reserved. Under VM pressure this would
cause problems when the dpcpu structures were overwritten by arbitrary
data; the most common symptom was a panic when netisr attempted to lock a
mutex.

For some reason the XEN code keeps track of the start of available memory
in the variables 'first', 'physfree', and 'init_first'; as far as I can
tell, we always have first == physfree == init_first * PAGE_SIZE. The
earlier commit adjusted 'first' (which, on !XEN, is the only variable
which tracks this value) but not the other two variables.

Exercise for reader: Eliminate two of these three variables.


# 216012 28-Nov-2010 kib

Calling fill_fpregs() for curthread is legitimate, and ELF coredump
does this.

Reported and tested by: pho
MFC after: 5 days


# 215865 26-Nov-2010 kib

Remove npxgetregs(), npxsetregs(), fpugetregs() and fpusetregs()
functions, they are unused. Remove 'user' from npxgetuserregs()
etc. names.

For {npx,fpu}{get,set}regs(), always use pcb->pcb_user_save for FPU
context storage. This eliminates the need for ugly copying with
overwrite of the newly added and reserved fields in ucontext on i386
to satisfy alignment requirements for fpusave() and fpurstor().

pc98 version was copied from i386.

Suggested and reviewed by: bde
Tested by: pho (i386 and amd64)
MFC after: 1 week


# 215008 08-Nov-2010 jhb

Remove stub symbols for APIC-related functions when 'device apic' is not
included in a kernel config. These stubs had existed previously so that
acpi.ko could always include the MADT parsing code and still link with a
kernel that did not include 'device apic'.


# 214835 05-Nov-2010 jhb

Adjust the order of operations in spinlock_enter() and spinlock_exit() to
work properly with single-stepping in a kernel debugger. Specifically,
these routines have always disabled interrupts before increasing the nesting
count and restored the prior state of interrupts after decreasing the nesting
count to avoid problems with a nested interrupt not disabling interrupts
when acquiring a spin lock. However, trap interrupts for single-stepping
can still occur even when interrupts are disabled. Now the saved state of
interrupts is not saved in the thread until after interrupts have been
disabled and the nesting count has been increased. Similarly, the saved
state from the thread cannot be read once the nesting count has been
decreased to zero. To fix this, use temporary variables to store interrupt
state and shuffle it between the thread's MD area and the appropriate
registers.

In cooperation with: bde
MFC after: 1 month


# 214681 02-Nov-2010 jhb

Further tweaks to the ram_attach() routine:
- Use > 2^32 - 1 instead of >= when checking for memory regions above 4G.
- Skip SMAP entries > 4G on i386 rather than breaking out of the loop
since SMAP entries are not guaranteed to be in order.
- Remove 'i' and loop over 'rid' directly in the dump_avail[] case.
- Only check for 4G regions in the dump_avail[] case on i386 if PAE is
enabled since vm_paddr_t is 32-bit in the !PAE case.

Submitted by: alc


# 214630 01-Nov-2010 jhb

Move the <machine/mca.h> header to <x86/mca.h>.


# 213748 12-Oct-2010 jkim

Remove trailing ", " from `sysctl machdep.idle_available' output.


# 213226 27-Sep-2010 jhb

Rewrite the i386 memory probe:
- Check for SMAP data from the loader first. If it exists, don't bother
doing any VM86 calls at all. This will be more friendly for non-BIOS
boot environments such as EFI, etc.
- Move the base memory setup into a new basemem_setup() routine instead
of duplicating it.
- Simplify the XEN case by removing all of the VM86/SMAP parsing code rather
than just jumping over it.
- Adjust some comments to better explain the code flow.

MFC after: 2 weeks


# 212541 13-Sep-2010 mav

Refactor timer management code with priority to one-shot operation mode.
The main goal of this is to generate timer interrupts only when there is
some work to do. When CPU is busy interrupts are generating at full rate
of hz + stathz to fullfill scheduler and timekeeping requirements. But
when CPU is idle, only minimum set of interrupts (down to 8 interrupts per
second per CPU now), needed to handle scheduled callouts is executed.
This allows significantly increase idle CPU sleep time, increasing effect
of static power-saving technologies. Also it should reduce host CPU load
on virtualized systems, when guest system is idle.

There is set of tunables, also available as writable sysctls, allowing to
control wanted event timer subsystem behavior:
kern.eventtimer.timer - allows to choose event timer hardware to use.
On x86 there is up to 4 different kinds of timers. Depending on whether
chosen timer is per-CPU, behavior of other options slightly differs.
kern.eventtimer.periodic - allows to choose periodic and one-shot
operation mode. In periodic mode, current timer hardware taken as the only
source of time for time events. This mode is quite alike to previous kernel
behavior. One-shot mode instead uses currently selected time counter
hardware to schedule all needed events one by one and program timer to
generate interrupt exactly in specified time. Default value depends of
chosen timer capabilities, but one-shot mode is preferred, until other is
forced by user or hardware.
kern.eventtimer.singlemul - in periodic mode specifies how much times
higher timer frequency should be, to not strictly alias hardclock() and
statclock() events. Default values are 2 and 4, but could be reduced to 1
if extra interrupts are unwanted.
kern.eventtimer.idletick - makes each CPU to receive every timer interrupt
independently of whether they busy or not. By default this options is
disabled. If chosen timer is per-CPU and runs in periodic mode, this option
has no effect - all interrupts are generating.

As soon as this patch modifies cpu_idle() on some platforms, I have also
refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions
(if supported) under high sleep/wakeup rate, as fast alternative to other
methods. It allows SMP scheduler to wake up sleeping CPUs much faster
without using IPI, significantly increasing performance on some highly
task-switching loads.

Tested by: many (on i386, amd64, sparc64 and powerc)
H/W donated by: Gheorghe Ardelean
Sponsored by: iXsystems, Inc.


# 211924 28-Aug-2010 rpaulo

Register an interrupt vector for DTrace return probes. There is some
code missing in lapic to make sure that we don't overwrite this entry,
but this will be done on a sequent commit.

Sponsored by: The FreeBSD Foundation


# 210294 20-Jul-2010 tijl

Store fsbase and gsbase in the right fields of the mcontext. They were
switched.

PR: i386/148344
Approved by: kib (mentor)
MFC after: 1 week


# 209613 30-Jun-2010 jhb

Move prototypes for kern_sigtimedwait() and kern_sigprocmask() to
<sys/syscallsubr.h> where all other kern_<syscall> prototypes live.


# 209463 23-Jun-2010 kib

Fix bugs on pc98, use npxgetuserregs() instead of npxgetregs() for
get_fpcontext(), and npxsetuserregs() for set_fpcontext). Also,
note that usercontext is not initialized anymore in fpstate_drop().

Systematically replace references to npxgetregs() and npxsetregs()
by npxgetuserregs() and npxsetuserregs() in comments.

Noted by: bde


# 209462 23-Jun-2010 kib

After the FPU use requires #MF working due to INT13 FPU exception handling
removal, MFi386 r209198:
Use critical sections instead of disabling local interrupts to ensure
the consistency between PCPU fpcurthread and the state of FPU.

Reviewed by: bde
Tested by: pho


# 208833 05-Jun-2010 kib

Introduce the x86 kernel interfaces to allow kernel code to use
FPU/SSE hardware. Caller should provide a save area that is chained
into the stack of the areas; pcb save_area for usermode FPU state is
on top. The pcb now contains a pointer to the current FPU saved area,
used during FPUDNA handling and context switches. There is also a
facility to allow the kernel thread to use pcb save_area.

Change the dreaded warnings "npxdna in kernel mode!" into the panics
when FPU usage is not registered.

KPI discussed with: fabient
Tested by: pho, fabient
Hardware provided by: Sentex Communications
MFC after: 1 month


# 208621 28-May-2010 jhb

Defer initializing machine checks for the boot CPU until the local APIC is
fully configured.

MFC after: 1 month


# 208604 27-May-2010 kib

Clarify a potential issue in get_fpcontext() use.

MFC after: 1 week


# 206553 13-Apr-2010 kib

Change printf() calls to uprintf() for sigreturn() and trap() complaints
about inacessible or wrong mcontext, and for dreaded "kernel trap with
interrupts disabled" situation. The later is changed when trap is
generated from user mode (shall never be ?).

Normalize the messages to include both pid and thread name.

MFC after: 1 week


# 205642 25-Mar-2010 nwhitehorn

Change the arguments of exec_setregs() so that it receives a pointer
to the image_params struct instead of several members of that struct
individually. This makes it easier to expand its arguments in the future
without touching all platforms.

Reviewed by: jhb


# 204309 25-Feb-2010 attilio

Introduce the new kernel sub-tree x86 which should contain all the code
shared and generalized between our current amd64, i386 and pc98.

This is just an initial step that should lead to a more complete effort.
For the moment, a very simple porting of cpufreq modules, BIOS calls and
the whole MD specific ISA bus part is added to the sub-tree but ideally
a lot of code might be added and more shared support should grow.

Sponsored by: Sandvine Incorporated
Reviewed by: emaste, kib, jhb, imp
Discussed on: arch
MFC: 3 weeks


# 200288 09-Dec-2009 kmacy

make PV core dump actually dump memory - still need to fix program header initialization


# 198507 27-Oct-2009 kib

In r197963, a race with thread being selected for signal delivery
while in kernel mode, and later changing signal mask to block the
signal, was fixed for sigprocmask(2) and ptread_exit(3). The same race
exists for sigreturn(2), setcontext(2) and swapcontext(2) syscalls.

Use kern_sigprocmask() instead of direct manipulation of td_sigmask to
reschedule newly blocked signals, closing the race.

Reviewed by: davidxu
Tested by: pho
MFC after: 1 month


# 197410 22-Sep-2009 jhb

- Split the logic to parse an SMAP entry out into a separate function on
amd64 similar to i386. This fixes a bug on amd64 where overlapping
entries would not cause the SMAP parsing to stop.
- Change the SMAP parsing code to do a sorted insertion into physmap[]
instead of an append to support systems with out-of-order SMAP entries.

PR: amd64/138220
Reported by: James R. Van Artsdalen james of jrv org
MFC after: 3 days


# 196829 04-Sep-2009 kib

Add missing ';'.


# 196412 20-Aug-2009 jkim

Check whether the SMBIOS reports reasonable amount of memory. If it is
less than "avail memory", fall back to Maxmem to avoid user confusion.
We use SMBIOS information to display "real memory" since r190599 but
some broken SMBIOS implementation reported only half of actual memory.

Tested by: bz
Approved by: re (kib)


# 196390 19-Aug-2009 ed

Make the MacBookPro3,1 hardware boot again.

Tested by: Patrick Lamaiziere <patfbsd davenulle org>
Approved by: re (kib)


# 196033 02-Aug-2009 ed

Make the MacBook3,1 boot again.

Approved by: re (kib)


# 195907 27-Jul-2009 rpaulo

Refine the MacBook hack to only match early models that have Intel ICH.

Discussed with: kjim
Approved by: re (kib)


# 194784 23-Jun-2009 jeff

Implement a facility for dynamic per-cpu variables.
- Modules and kernel code alike may use DPCPU_DEFINE(),
DPCPU_GET(), DPCPU_SET(), etc. akin to the statically defined
PCPU_*. Requires only one extra instruction more than PCPU_* and is
virtually the same as __thread for builtin and much faster for shared
objects. DPCPU variables can be initialized when defined.
- Modules are supported by relocating the module's per-cpu linker set
over space reserved in the kernel. Modules may fail to load if there
is insufficient space available.
- Track space available for modules with a one-off extent allocator.
Free may block for memory to allocate space for an extent.

Reviewed by: jhb, rwatson, kan, sam, grehan, marius, marcel, stas


# 193804 09-Jun-2009 ariff

Move C1E workaround into its own idle function. Previous workaround works
only during initial booting process, while there are laptops/BIOSes that
tend to act 'smarter' by force enabling C1E if the main power adapter
being pulled out, rendering previous workaround ineffective. Given the
fact that we still rely on local APIC to drive timer interrupt, this
workaround should keep all Turion (probably Phenom too) X\d+ alive whether
its on battery power or not.

URL: http://lists.freebsd.org/pipermail/freebsd-acpi/2008-April/004858.html
http://lists.freebsd.org/pipermail/freebsd-acpi/2008-May/004888.html

Tested by: Peter Jeremy <peterjeremy at optushome d com d au>


# 192323 18-May-2009 marcel

Add cpu_flush_dcache() for use after non-DMA based I/O so that a
possible future I-cache coherency operation can succeed. On ARM
for example the L1 cache can be (is) virtually mapped, which
means that any I/O that uses temporary mappings will not see the
I-cache made coherent. On ia64 a similar behaviour has been
observed. By flushing the D-cache, execution of binaries backed
by md(4) and/or NFS work reliably.
For Book-E (powerpc), execution over NFS exhibits SIGILL once in
a while as well, though cpu_flush_dcache() hasn't been implemented
yet.

Doing an explicit D-cache flush as part of the non-DMA based I/O
read operation eliminates the need to do it as part of the
I-cache coherency operation itself and as such avoids pessimizing
the DMA-based I/O read operations for which D-cache are already
flushed/invalidated. It also allows future optimizations whereby
the bcopy() followed by the D-cache flush can be integrated in a
single operation, which could be implemented using on-chips DMA
engines, by-passing the D-cache altogether.


# 192050 13-May-2009 jhb

Implement simple machine check support for amd64 and i386.
- For CPUs that only support MCE (the machine check exception) but not MCA
(i.e. Pentium), all this does is print out the value of the machine check
registers and then panic when a machine check exception occurs.
- For CPUs that support MCA (the machine check architecture), the support is
a bit more involved.
- First, there is limited support for decoding the CPU-independent MCA
error codes in the kernel, and the kernel uses this to output a short
description of any machine check events that occur.
- When a machine check exception occurs, all of the MCx banks on the
current CPU are scanned and any events are reported to the console
before panic'ing.
- To catch events for correctable errors, a periodic timer kicks off a
task which scans the MCx banks on all CPUs. The frequency of these
checks is controlled via the "hw.mca.interval" sysctl.
- Userland can request an immediate scan of the MCx banks by writing
a non-zero value to "hw.mca.force_scan".
- If any correctable events are encountered, the appropriate details
are stored in a 'struct mca_record' (defined in <machine/mca.h>).
The "hw.mca.count" is a count of such records and each record may
be queried via the "hw.mca.records" tree by specifying the record
index (0 .. count - 1) as the next name in the MIB similar to using
PIDs with the kern.proc.* sysctls. The idea is to export machine
check events to userland for more detailed processing.
- The periodic timer and hw.mca sysctls are only present if the CPU
supports MCA.

Discussed with: emaste (briefly)
MFC after: 1 month


# 190919 11-Apr-2009 ed

Simplify in/out functions (for i386 and AMD64).

Remove a hack to generate more efficient code for port numbers below
0x100, which has been obsolete for at least ten years, because GCC has
an asm constraint to specify that.

Submitted by: Christoph Mallon <christoph mallon gmx de>


# 190617 01-Apr-2009 kib

Fill the fsbase and gsbase fields of the mcontext structure on i386.

In collaboration with: pho
Discussed with: peter
Reviewed by: jhb


# 190600 31-Mar-2009 jkim

Fix an uninitialized variable from the previous commit.


# 190599 31-Mar-2009 jkim

Probe size of installed memory modules from loader and display it
as 'real memory' instead of Maxmem if the value is available.
Note amd64 displayed physmem as 'usable memory' since machdep.c r1.640
to unconfuse users. Now it is consistent across amd64 and i386 again.
While I am here, clean up smbios.c a bit and update copyright date.

Reviewed by: jhb


# 190447 26-Mar-2009 kib

Convert gdt_segs and ldt_segs initialization to C99 style.

Reviewed by: jhb


# 189423 05-Mar-2009 jhb

A better fix for handling different FPU initial control words for different
ABIs:
- Store the FPU initial control word in the pcb for each thread.
- When first using the FPU, load the initial control word after restoring
the clean state if it is not the standard control word.
- Provide a correct control word for Linux/i386 binaries under
FreeBSD/amd64.
- Adjust the control word returned for fpugetregs()/npxgetregs() when a
thread hasn't used the FPU yet to reflect the real initial control
word for the current ABI.
- The Linux/i386 ABI for FreeBSD/i386 now properly sets the right control
word instead of trashing whatever the current state of the FPU is.

Reviewed by: bde


# 186557 29-Dec-2008 kmacy

merge 186535, 186537, and 186538 from releng_7_xen

Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep

Log:
unmask evtchn in bind_{virq, ipi}_to_irq

Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic


# 182902 10-Sep-2008 kmacy

Get initial bootstrap of APs working under xen.
Note that the APs still blow up in sched_throw().

MFC after: 1 month


# 181911 20-Aug-2008 kmacy

- clean up interrupt handling for xen a tiny bit
- parse the command line in to kenv
- defer shutdown watcher until later in boot

MFC after: 1 month


# 181894 20-Aug-2008 kmacy

don't use cpu_idle_acpi under xen

MFC after: 1 month


# 181809 17-Aug-2008 kmacy

remove code in XEN version of init386 causing initialization failure

MFC after: 1 month


# 181775 15-Aug-2008 kmacy

Integrate support for xen in to i386 common code.

MFC after: 1 month


# 178471 25-Apr-2008 jeff

- Add an integer argument to idle to indicate how likely we are to wake
from idle over the next tick.
- Add a new MD routine, cpu_wake_idle() to wakeup idle threads who are
suspended in cpu specific states. This function can fail and cause the
scheduler to fall back to another mechanism (ipi).
- Implement support for mwait in cpu_idle() on i386/amd64 machines that
support it. mwait is a higher performance way to synchronize cpus
as compared to hlt & ipis.
- Allow selecting the idle routine by name via sysctl machdep.idle. This
replaces machdep.cpu_idle_hlt. Only idle routines supported by the
current machine are permitted.

Sponsored by: Nokia


# 178429 22-Apr-2008 phk

Now that all platforms use genclock, shuffle things around slightly
for better structure.

Much of this is related to <sys/clock.h>, which should really have
been called <sys/calendar.h>, but unless and until we need the name,
the repocopy can wait.

In general the kernel does not know about minutes, hours, days,
timezones, daylight savings time, leap-years and such. All that
is theoretically a matter for userland only.

Parts of kernel code does however care: badly designed filesystems
store timestamps in local time and RTC chips almost universally
track time in a YY-MM-DD HH:MM:SS format, and sometimes in local
timezone instead of UTC. For this we have <sys/clock.h>

<sys/time.h> on the other hand, deals with time_t, timeval, timespec
and so on. These know only seconds and fractions thereof.

Move inittodr() and resettodr() prototypes to <sys/time.h>.
Retain the names as it is one of the few surviving PDP/VAX references.

Move startrtclock() to <machine/clock.h> on relevant platforms, it
is a MD call between machdep.c/clock.c. Remove references to it
elsewhere.

Remove a lot of unnecessary <sys/clock.h> includes.

Move the machdep.disable_rtc_set sysctl to subr_rtc.c where it belongs.
XXX: should be kern.disable_rtc_set really, it's not MD.


# 177253 16-Mar-2008 rwatson

In keeping with style(9)'s recommendations on macros, use a ';'
after each SYSINIT() macro invocation. This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, including cflow's prcc and lxr.

MFC after: 1 month
Discussed with: imp, rink


# 177155 13-Mar-2008 jhb

Use the SMAP data from the loader if it is provided instead of using
virtual 86 mode to query the BIOS directly. This is needed for certain
HP machines whose BIOS only provide an SMAP when invoked from real mode.
On such machines the loader will be able to query the SMAP successfully
due to the recent BTX changes, but the kernel will not.

One thing I'm not sure of is if we can skip the INT 12h probe altogether
if we have the SMAP from the loader as it seems that we do the INT 12h
probe to setup enough state so we can use vm86 to call the BIOS.

MFC after: 1 week


# 177145 13-Mar-2008 kib

Since version 4.3, gcc changed its behaviour concerning the i386/amd64
ABI and the direction flag, that is it now assumes that the direction
flag is cleared at the entry of a function and it doesn't clear once
more if needed. This new behaviour conforms to the i386/amd64 ABI.

Modify the signal handler frame setup code to clear the DF {e,r}flags
bit on the amd64/i386 for the signal handlers.

jhb@ noted that it might break old apps if they assumed DF == 1 would be
preserved in the signal handlers, but that such apps should be rare and
that older versions of gcc would not generate such apps.

Submitted by: Aurelien Jarno <aurelien aurel32 net>
PR: 121422
Reviewed by: jhb
MFC after: 2 weeks


# 175020 31-Dec-2007 jhb

Include a "pae" feature if an i386 kernel is built with PAE support.

Obtained from: Yahoo!


# 174898 25-Dec-2007 rwatson

Add a new 'why' argument to kdb_enter(), and a set of constants to use
for that argument. This will allow DDB to detect the broad category of
reason why the debugger has been entered, which it can use for the
purposes of deciding which DDB script to run.

Assign approximate why values to all current consumers of the
kdb_enter() interface.


# 174677 16-Dec-2007 rpaulo

Fix previous commit. The code ended up in the wrong function.

Approved by: njl (mentor)


# 174557 12-Dec-2007 rpaulo

Disallow the legacy USB circuit to generate an SMI# via an ICH
register (MacBooks only).
This allows MacBooks to boot in SMP mode without any trick and solves
the timer problems with HZ=1000.

MFC after: 1 week

Reviewed by: njl (mentor), jhb
Approved by: njl (mentor), jhb


# 173592 13-Nov-2007 peter

Drastically simplify the i386 pcpu backend by merging parts of the
amd64 mechanism over. Instead of page table hackery that isn't
actually needed, just use 'struct pcpu __pcpu[MAXCPU]' for backing like
all the other platforms do. Get rid of 'struct privatespace' and a
while mess of #ifdef SMP garbage that set it up. As a bonus, this
returns the 4MB of KVA that we stole to implement it the old way.
This also allows you to read the pcpu data for each cpu when reading a
minidump.

Background information: Originally, pcpu stuff was implemented as having
per-cpu page tables and magic to make different data structures appear
at the same actual address. In order to share page tables, we switched
to using the GDT and %fs/%gs to access it. But we still did the evil
magic to set it up for the old way. The "idle stacks" are not used
for the idle process anymore and are just used for a few functions during
bootup, then ignored. (excercise for reader: free these afterwards).


# 173361 05-Nov-2007 kib

Fix for the panic("vm_thread_new: kstack allocation failed") and
silent NULL pointer dereference in the i386 and sparc64 pmap_pinit()
when the kmem_alloc_nofault() failed to allocate address space. Both
functions now return error instead of panicing or dereferencing NULL.

As consequence, vmspace_exec() and vmspace_unshare() returns the errno
int. struct vmspace arg was added to vm_forkproc() to avoid dealing
with failed allocation when most of the fork1() job is already done.

The kernel stack for the thread is now set up in the thread_alloc(),
that itself may return NULL. Also, allocation of the first process
thread is performed in the fork1() to properly deal with stack
allocation failure. proc_linkup() is separated into proc_linkup()
called from fork1(), and proc_linkup0(), that is used to set up the
kernel process (was known as swapper).

In collaboration with: Peter Holm
Reviewed by: jhb


# 173118 28-Oct-2007 jhb

- Add constants for the different memory types in the SMAP table.
- Use the SMAP types and constants from <machine/pc/bios.h> in the boot
code rather than duplicating it.


# 171797 09-Aug-2007 njl

Add "show sysregs" command to ddb. On i386, this gives gdt, idt, ldt,
cr0-4, etc. Support should be added for other platforms that have a
different set of registers for system use.

Loosely based on: OpenBSD
Approved by: re


# 170368 06-Jun-2007 davidxu

Backout experimental adaptive-spin umtx code.


# 170319 05-Jun-2007 alc

Add the machine-specific definitions for configuring the new physical
memory allocator.

Set the size of phys_avail[] and dump_avail[] using one of these
definitions.

Approved by: re


# 170307 05-Jun-2007 jeff

Commit 14/14 of sched_lock decomposition.
- Use thread_lock() rather than sched_lock for per-thread scheduling
sychronization.
- Use the per-process spinlock rather than the sched_lock for per-process
scheduling synchronization.

Tested by: kris, current@
Tested on: i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)


# 170170 31-May-2007 attilio

Revert VMCNT_* operations introduction.
Probabilly, a general approach is not the better solution here, so we should
solve the sched_lock protection problems separately.

Requested by: alc
Approved by: jeff (mentor)


# 170110 29-May-2007 attilio

Fix some problems introduced with the last descriptors tables locking
patch:
- Do the correct test for ldt allocation
- Drop dt_lock just before to call kmem_free (since it acquires blocking
locks inside)
- Solve a deadlock with smp_rendezvous() where other CPU will wait
undefinitively for dt_lock acquisition.
- Add dt_lock in the WITNESS list of spinlocks

While applying these modifies, change the requirement for user_ldt_free()
making that returning without dt_lock held.

Tested by: marcus, tegge
Reviewed by: tegge
Approved by: jeff (mentor)


# 169802 20-May-2007 jeff

- Move GDT/LDT locking into a seperate spinlock, removing the global
scheduler lock from this responsibility.

Contributed by: Attilio Rao <attilio@FreeBSD.org>
Tested by: jeff, kkenn


# 169667 18-May-2007 jeff

- define and use VMCNT_{GET,SET,ADD,SUB,PTR} macros for manipulating
vmcnts. This can be used to abstract away pcpu details but also changes
to use atomics for all counters now. This means sched lock is no longer
responsible for protecting counts in the switch routines.

Contributed by: Attilio Rao <attilio@FreeBSD.org>


# 167668 17-Mar-2007 alc

Eliminate an unused parameter.


# 167247 05-Mar-2007 jhb

Use vm_paddr_t rather than uintptr_t when passing the physical address of
APICs to lapic_init() and ioapic_create().


# 166186 23-Jan-2007 bde

Cleaned up declaration and initialization of clock_lock. It is only
used by clock code, so don't export it to the world for machdep.c to
initialize. There is a minor problem initializing it before it is
used, since although clock initialization is split up so that parts
of it can be done early, the first part was never done early enough
to actually work. Split it up a bit more and do the first part as
late as possible to document the necessary order. The functions that
implement the split are still bogusly exported.

Cleaned up initialization of the i8254 clock hardware using the new
split. Actually initialize it early enough, and don't work around it
not being initialized in DELAY() when DELAY() is called early for
initialization of some console drivers.

This unfortunately moves a little more code before the early debugger
breakpoint so that it is harder to debug. The ordering of console and
related initialization is delicate because we want to do as little as
possible before the breakpoint, but must initialize a console.


# 166001 14-Jan-2007 kmacy

exclude the icu and clock lock from LOCK_PROFILING


# 165369 20-Dec-2006 davidxu

Add a lwpid field into per-cpu structure, the lwpid represents current
running thread's id on each cpu. This allow us to add in-kernel adaptive
spin for user level mutex. While spinning in user space is possible,
without correct thread running state exported from kernel, it hardly
can be implemented efficiently without wasting cpu cycles, however
exporting thread running state unlikely will be implemented soon as
it has to design and stablize interfaces. This implementation is
transparent to user space, it can be disabled dynamically. With this
change, mutex ping-pong program's performance is improved massively on
SMP machine. performance of mysql super-smack select benchmark is increased
about 7% on Intel dual dual-core2 Xeon machine, it indicates on systems
which have bunch of cpus and system-call overhead is low (athlon64, opteron,
and core-2 are known to be fast), the adaptive spin does help performance.

Added sysctls:
kern.threads.umtx_dflt_spins
if the sysctl value is non-zero, a zero umutex.m_spincount will
cause the sysctl value to be used a spin cycle count.
kern.threads.umtx_max_spins
the sysctl sets upper limit of spin cycle count.

Tested on: Athlon64 X2 3800+, Dual Xeon 5130


# 164951 06-Dec-2006 sobomax

Allow machdep.cpu_idle_hlt to be set from the loader. This should allow
to workaround the problem with SMP kernels on Turion64 X2 processors
described in kern/104678 and may be useful in other situations too.

MFC after: 3 days


# 164936 06-Dec-2006 julian

Threading cleanup.. part 2 of several.

Make part of John Birrell's KSE patch permanent..
Specifically, remove:
Any reference of the ksegrp structure. This feature was
never fully utilised and made things overly complicated.
All code in the scheduler that tried to make threaded programs
fair to unthreaded programs. Libpthread processes will already
do this to some extent and libthr processes already disable it.

Also:
Since this makes such a big change to the scheduler(s), take the opportunity
to rename some structures and elements that had to be moved anyhow.
This makes the code a lot more readable.

The ULE scheduler compiles again but I have no idea if it works.

The 4bsd scheduler still reqires a little cleaning and some functions that now do
ALMOST nothing will go away, but I thought I'd do that as a separate commit.

Tested by David Xu, and Dan Eischen using libthr and libpthread.


# 164413 19-Nov-2006 alc

The global variable avail_end is redundant and only used once. Eliminate
it. Make avail_start static to the pmap on amd64. (It no longer exists
on other architectures.)


# 164362 17-Nov-2006 jhb

- Add macro constants for the various fields in %dr7 and use them in place
of various scattered magic values.
- Pretty print the address of hardware watchpoints in 'show watch' rather
than just displaying hex.
- Expand address field width on amd64 for 64-bit pointers.


# 164303 15-Nov-2006 jhb

Various whitespace and style fixes.


# 164078 07-Nov-2006 ru

Spelling.


# 164064 07-Nov-2006 jhb

Remove duplicate IDTVEC macro definition, it's already defined in
<machine/intr_machdep.h>.


# 163709 26-Oct-2006 jb

Make KSE a kernel option, turned on by default in all GENERIC
kernel configs except sun4v (which doesn't process signals properly
with KSE).

Reviewed by: davidxu@


# 162958 02-Oct-2006 phk

Second part of a little cleanup in the calendar/timezone/RTC handling.

Split subr_clock.c in two parts (by repo-copy):
subr_clock.c contains generic RTC and calendaric stuff. etc.
subr_rtc.c contains the newbus'ified RTC interface.

Centralize the machdep.{adjkerntz,disable_rtc_set,wall_cmos_clock}
sysctls and associated variables into subr_clock.c. They are
not machine dependent and we have generic code that relies on being
present so they are not even optional.


# 162954 02-Oct-2006 phk

First part of a little cleanup in the calendar/timezone/RTC handling.

Move relevant variables to <sys/clock.h> and fix #includes as necessary.

Use libkern's much more time- & spamce-efficient BCD routines.


# 162839 30-Sep-2006 phk

Remove the no longer relevant or correct bootinfo sysctls.


# 162112 07-Sep-2006 jhb

Use a single constant to define the sizes of the physmap[], phys_avail[],
and dump_avail[] arrays so they are in sync (previously it was possible
to store more entries in the physmap[] then we could store in phys_avail[],
which was pointless). While I'm here, bump up the length of these tables
to hold 30 entries on amd64 and 16 on i386. This allows machines with
fairly fragmented memory maps to boot ok (at least one machine would
not boot FreeBSD/i386 but would boot FreeBSD/amd64 because amd64 allowed
for more fragments).

MFC after: 3 days


# 161140 09-Aug-2006 imp

Minor style(9) nit.


# 160772 27-Jul-2006 jhb

Argh, fix compile with XBOX enabled. Somehow I missed a LINT compile. :(


# 160763 27-Jul-2006 jhb

Don't allow MAXMEM or hw.physmem to extend the top of memory if our memory
map was obtained from the SMAP. SMAP is trustworthy, and the memory
extending feature is a band-aid for older systems where FreeBSD's methods
of detecting memory were not always trustworthy. This fixes the issue
where using hw.physmem could result in the ACPI tables getting trashed
breaking ACPI.

MFC after: 3 days
Tested on: i386


# 160312 12-Jul-2006 jhb

Simplify the pager support in DDB. Allowing different db commands to
install custom pager functions didn't actually happen in practice (they
all just used the simple pager and passed in a local quit pointer). So,
just hardcode the simple pager as the only pager and make it set a global
db_pager_quit flag that db commands can check when the user hits 'q' (or a
suitable variant) at the pager prompt. Also, now that it's easy to do so,
enable paging by default for all ddb commands. Any command that wishes to
honor the quit flag can do so by checking db_pager_quit. Note that the
pager can also be effectively disabled by setting $lines to 0.

Other fixes:
- 'show idt' on i386 and pc98 now actually checks the quit flag and
terminates early.
- 'show intr' now actually checks the quit flag and terminates early.


# 159089 31-May-2006 davidxu

Clear invalid bits only if CPU supports SSE, otherwise, some fields in
struct save87 will be cleared unexpectly.


# 159087 30-May-2006 davidxu

Use the method described in IA-32 Intel Architecture Software Developer's
Manual chapter 11.6.6 to get valid mxcsr bits, use the mxcsr mask to clear
invalid bits passed by user code.

Reviewed by: bde


# 159000 28-May-2006 davidxu

Clear high 16 bits of mxcsr register, according to Intel document, if
the high 16 bits is non-zero, fxrstor instruction will generate GP fault,
resulting kernel crash, this bug can be triggered by setcontext and
ptrace(PT_SETXMMREGS).


# 158445 11-May-2006 phk

Clean out sysctl machdep.* related defines.

The cmos clock related stuff should really be in MI code.


# 157568 06-Apr-2006 jhb

- Don't set CR0_NE and CR0_MP in npx_probe() as they are already set
earlier in cpu_setregs().
- If we know this CPU has a FPU via cpuid, then just assume the INT16
interface and make the npx device quiet to not clutter the dmesg. This
is true for all Pentium and later CPUs and even some of the later 486dx
CPUs.

Reviewed by: bde
Tested by: ps
MFC after: 1 week


# 156706 14-Mar-2006 jhb

Don't allow userland to set hardware watch points on kernel memory at all.
Previously, we tried to allow this only for root. However, we were calling
suser() on the *target* process rather than the current process. This
means that if you can ptrace() a process running as root you can set a
hardware watch point in the kernel. In practice I think you probably have
to be root in order to pass the p_candebug() checks in ptrace() to attach
to a process running as root anyway. Rather than fix the suser(), I just
axed the entire idea, as I can't think of any good reason _at all_ for
userland to set hardware watch points for KVM.

MFC after: 3 days
Also thinks hardware watch points on KVM from userland are bad: bde, rwatson


# 155510 10-Feb-2006 rink

Cleaned the memory initialization up, moved some defines from the framebuffer
to an include file.

Reviewed by: imp
Approved by: imp (mentor)


# 155238 03-Feb-2006 davidxu

Clear carry flag in get_mcontext so that setcontext does not
return a bogus error.

PR: misc/92110


# 153726 26-Dec-2005 davidxu

Move global variable private_tss into per-cpu area.

Reviewed by: jhb


# 152753 24-Nov-2005 ru

Add missing "struct" in i386/i386/machdep.c,v 1.497 by deischen@.


# 152219 09-Nov-2005 imp

Add support for XBOX to the FreeBSD port. The xbox architecture is
nearly identical to wintel/ia32, with a couple of tweaks. Since it is
so similar to ia32, it is optionally added to a i386 kernel. This
port is preliminary, but seems to work well. Further improvements
will improve the interaction with syscons(4), port Linux nforce driver
and future versions of the xbox.

This supports the 64MB and 128MB boxes. You'll need the most recent
CVS version of Cromwell (the Linux BIOS for the XBOX) to boot.

Rink will be maintaining this port, and is interested in feedback.
He's setup a website http://xbox-bsd.nl to report the latest
developments.

Any silly mistakes are my fault.

Submitted by: Rink P.W. Springer rink at stack dot nl and
Ed Schouten ed at fxq dot nl


# 151316 14-Oct-2005 davidxu

1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most
changes in MD code are trivial, before this change, trapsignal and
sendsig use discrete parameters, now they uses member fields of
ksiginfo_t structure. For sendsig, this change allows us to pass
POSIX realtime signal value to user code.

2. Remove cpu_thread_siginfo, it is no longer needed because we now always
generate ksiginfo_t data and feed it to libpthread.

3. Add p_sigqueue to proc structure to hold shared signals which were
blocked by all threads in the proc.

4. Add td_sigqueue to thread structure to hold all signals delivered to
thread.

5. i386 and amd64 now return POSIX standard si_code, other arches will
be fixed.

6. In this sigqueue implementation, pending signal set is kept as before,
an extra siginfo list holds additional siginfo_t data for signals.
kernel code uses psignal() still behavior as before, it won't be failed
even under memory pressure, only exception is when deleting a signal,
we should call sigqueue_delete to remove signal from sigqueue but
not SIGDELSET. Current there is no kernel code will deliver a signal
with additional data, so kernel should be as stable as before,
a ksiginfo can carry more information, for example, allow signal to
be delivered but throw away siginfo data if memory is not enough.
SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
not be caught or masked.
The sigqueue() syscall allows user code to queue a signal to target
process, if resource is unavailable, EAGAIN will be returned as
specification said.
Just before thread exits, signal queue memory will be freed by
sigqueue_flush.
Current, all signals are allowed to be queued, not only realtime signals.

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64


# 147950 13-Jul-2005 jkoshy

Use an interrupt gate for the NMI handler and prevent too-early
enabling of interrupts inside of trap(). Fix a typo in a comment.

Revert rev 1.113 of "sys/i386/i386/exception.s" as it is no longer
needed.

Reviewed by: bde
MFC after: 3 days


# 147741 02-Jul-2005 delphij

Remove the CPU_ENABLE_SSE option from the i386 and pc98 architectures,
as they are already default for I686_CPU for almost 3 years, and
CPU_DISABLE_SSE always disables it. On the other hand, CPU_ENABLE_SSE
does not work for I486_CPU and I586_CPU.

This commit has:
- Removed the option from conf/options.*
- Removed the option and comments from MD NOTES files
- Simplified the CPU_ENABLE_SSE ifdef's so they don't
deal with CPU_ENABLE_SSE from kernel configuration. (*)

For most users, this commit should be largely no-op. If you used to
place CPU_ENABLE_SSE into your kernel configuration for some reason,
it is time to remove it.

(*) The ifdef's of CPU_ENABLE_SSE are not removed at this point, since
we need to change it to !defined(CPU_DISABLE_SSE) && defined(I686_CPU),
not just !defined(CPU_DISABLE_SSE), if we really want to do so.

Discussed on: -arch
Approved by: re (scottl)


# 147671 29-Jun-2005 peter

Switch AMD64 and i386 platforms to using ELF as their kernel crash
dump format. The key reason to do this is so that we can dump sparse
address space. For example, we need to be able to skip the PCI hole
just below the 4GB boundary. Trying to destructively dump MMIO device
registers is Really Bad(TM). The frequent result of trying to do a
crash dump on a machine with 4GB or more ram was ugly (lockup or reboot).

This code has been taken directly from the IA64 dump_machdep.c code,
with just a few (mostly minor) mods.

Introduce a dump_avail[] array in the machdep.c code so that we have a
source of truth for what memory is present in a machine that needs to be
dumped. We can't use phys_avail[] because all sorts of things slice
memory out of it that we really need to dump. eg: the vm page array
and the dmesg buffer. dump_avail[] is pretty much an unmolested version
of phys_avail[]. It does have Maxmem correction.

Bump the i386 and amd64 dump format to version 2, but nothing actually
uses this. amd64 was actually using the i386 dump version number.

libkvm support to follow.

Approved by: re


# 145913 05-May-2005 peter

Move the pcb variable initialization earlier. This is cosmetic here, but
in as-yet uncommitted code for 32 bit binary compatability on 64 bit
kernels, some of the 32 bit registers come from the pcb. Moving the
initialization here means fill_regs32() etc are laid out the same.


# 145080 14-Apr-2005 jhb

Remove support for mixed mode altogether now that we no longer use IRQ 0
when using an APIC. This simplifies the APIC code somewhat and also allows
us to be pedantically more compliant with ACPI which mandates no use of
mixed mode.


# 145034 13-Apr-2005 peter

Change the segment limits to 4GB, we set the user accessible bit on all
of the kernel address space already. Intel recommend this anyway, because
using a non-4GB limit adds an additional clock cycle to address generation.
We were able to install 4GB segments into the LDT, so any limits we imposed
on %cs and %ds were academic anyway. More importantly, this allows us to
make a page in the kernel readable to user applications, for holding things
like the signal trampoline and other fun things.

Move the user %cs/%ds segments from the LDT to the GDT. There was no good
reason for them to be there anyway. The old LDT entries are still there
but we can now relax the restriction that prevented users from emptying
the default LDT entries.

Putting user and kernel %cs and %ds together allows us to access the fast
sysenter/sysexit/syscall/sysret instructions. syscall/sysret in particular
require that the user/kernel segments be laid out this way. Reserve a slot
specifically for NDIS while here.

Create two user controllable slots in the GDT that are context switched
with the (kernel) thread. This allows user applications to set two
user privilige selectors to arbitary values. Create
i386_set_fsbase(void *base) and friends. (get/set, fs/gs). For i386,
%gs is used by tls and the thread libraries and this means that user
processes no longer have to have the cost of having a custom LDT, and
we will no longer to do a ldt switch when activating a kthread/ithread in
the usual case any more.

In other words, we can now set the base address for %fs and %gs to arbitary
addresses without the pain of messing with ldt segments.


# 144637 04-Apr-2005 jhb

Divorce critical sections from spinlocks. Critical sections as denoted by
critical_enter() and critical_exit() are now solely a mechanism for
deferring kernel preemptions. They no longer have any affect on
interrupts. This means that standalone critical sections are now very
cheap as they are simply unlocked integer increments and decrements for the
common case.

Spin mutexes now use a separate KPI implemented in MD code: spinlock_enter()
and spinlock_exit(). This KPI is responsible for providing whatever MD
guarantees are needed to ensure that a thread holding a spin lock won't
be preempted by any other code that will try to lock the same lock. For
now all archs continue to block interrupts in a "spinlock section" as they
did formerly in all critical sections. Note that I've also taken this
opportunity to push a few things into MD code rather than MI. For example,
critical_fork_exit() no longer exists. Instead, MD code ensures that new
threads have the correct state when they are created. Also, we no longer
try to fixup the idlethreads for APs in MI code. Instead, each arch sets
the initial curthread and adjusts the state of the idle thread it borrows
in order to perform the initial context switch.

This change is largely a big NOP, but the cleaner separation it provides
will allow for more efficient alternative locking schemes in other parts
of the kernel (bare critical sections rather than per-CPU spin mutexes
for per-CPU data for example).

Reviewed by: grehan, cognet, arch@, others
Tested on: i386, alpha, sparc64, powerpc, arm, possibly more


# 143157 05-Mar-2005 des

Use TUNABLE_ULONG_FETCH to retrieve hw.physmem; getenv_quad() will take
care of the multiplier suffix.


# 143156 05-Mar-2005 des

Replace goto with continue.


# 142834 28-Feb-2005 wes

Add a sysctl that records the amount of physical memory in the machine.

Submitted by: Nicko Dehaine <nicko@stbernard.com>
MFC after: 1 day


# 141378 06-Feb-2005 njl

Finish the job of sorting all includes and fix the build by including
malloc.h before proc.h on sparc64. Noticed by das@

Compiled on: alpha, amd64, i386, pc98, sparc64


# 141374 05-Feb-2005 njl

Make cpu_est_clockrate() more accurate by disabling interrupts for the
millisecond it is calibrating. Suggested by jhb@ and bde@. Don't clobber
the tsc_freq with the new value since it isn't accurate enough for
timecounters and the timecounter system as a whole needs support for
changing rates before we do this. Subtract 0.5% from our measurement
to account for overhead in DELAY. Note that this interface is for
estimating the clockrate and needs to work well at runtime so doing a full
calibration including disabling interrupts for a second is not feasible.


# 141237 04-Feb-2005 njl

Add an implementation of cpu_est_clockrate(9). This function estimates the
current clock frequency for the given CPU id in units of Hz.


# 140451 18-Jan-2005 jhb

Tweak the ELCR support slightly. Explicitly probe the ELCR during boot
instead of burying that in the atpic(4) code as atpic(4) is not the only
user of elcr(4). Change the elcr(4) code to export a global elcr_found
variable that other code can check to see if a valid ELCR was found.

MFC after: 1 month


# 138129 27-Nov-2004 das

Don't include sys/user.h merely for its side-effect of recursively
including other headers.


# 137912 20-Nov-2004 das

U areas are going away, so don't allocate one for process 0.

Reviewed by: arch@


# 137784 16-Nov-2004 jhb

Initiate deorbit burn sequence for 80386 support in FreeBSD: Remove
80386 (I386_CPU) support from the kernel.


# 137117 01-Nov-2004 jhb

- Change the ddb paging "support" to use a variable (db_lines_per_page) to
control the number of lines per page rather than a constant. The variable
can be examined and changed in ddb as '$lines'. Setting the variable to
0 will effectively turn off paging.
- Change db_putchar() to force out pending whitespace before outputting
newlines and carriage returns so that one can rub out content on the
current line via '\r \r' type strings.
- Change the simple pager to rub out the --More-- prompt explicitly when
the routine exits.
- Add some aliases to the simple pager to make it more compatible with
more(1): 'e' and 'j' do a single line. 'd' does half a page, and
'f' does a full page.

MFC after: 1 month
Inspired by: kris


# 136897 24-Oct-2004 simokawa

Preserve dcons(4) buffer passed by loader(8).


# 134791 05-Sep-2004 julian

Refactor a bunch of scheduler code to give basically the same behaviour
but with slightly cleaned up interfaces.

The KSE structure has become the same as the "per thread scheduler
private data" structure. In order to not make the diffs too great
one is #defined as the other at this time.

The KSE (or td_sched) structure is now allocated per thread and has no
allocation code of its own.

Concurrency for a KSEGRP is now kept track of via a simple pair of counters
rather than using KSE structures as tokens.

Since the KSE structure is different in each scheduler, kern_switch.c
is now included at the end of each scheduler. Nothing outside the
scheduler knows the contents of the KSE (aka td_sched) structure.

The fields in the ksegrp structure that are to do with the scheduler's
queueing mechanisms are now moved to the kg_sched structure.
(per ksegrp scheduler private data structure). In other words how the
scheduler queues and keeps track of threads is no-one's business except
the scheduler's. This should allow people to write experimental
schedulers with completely different internal structuring.

A scheduler call sched_set_concurrency(kg, N) has been added that
notifies teh scheduler that no more than N threads from that ksegrp
should be allowed to be on concurrently scheduled. This is also
used to enforce 'fainess' at this time so that a ksegrp with
10000 threads can not swamp a the run queue and force out a process
with 1 thread, since the current code will not set the concurrency above
NCPU, and both schedulers will not allow more than that many
onto the system run queue at a time. Each scheduler should eventualy develop
their own methods to do this now that they are effectively separated.

Rejig libthr's kernel interface to follow the same code paths as
linkse for scope system threads. This has slightly hurt libthr's performance
but I will work to recover as much of it as I can.

Thread exit code has been cleaned up greatly.
exit and exec code now transitions a process back to
'standard non-threaded mode' before taking the next step.
Reviewed by: scottl, peter
MFC after: 1 week


# 133145 05-Aug-2004 rwatson

Move definition of mem_range_softc from mp_machdep.c to machdep.c so
that it is defined for non-SMP builds, not just SMP ones.


# 132376 19-Jul-2004 silby

Add a #error requiring KDB if DDB is specified. (This can probably be
relocated to a better place, if one exists.)


# 132088 13-Jul-2004 davidxu

Add ptrace_clear_single_step(), alpha already has it for years, the function
will be used by ptrace to clear a thread's single step state.


# 131944 10-Jul-2004 marcel

Update for the KDB framework:
o Make debugging code conditional upon KDB instead of DDB.
o Declare ksym_start and ksym_end as extern and initialize them.
This was previously and bogusly handled by DDB itself.
o Call kdb_enter() instead of Debugger().
o Remove implementation of Debugger().


# 131905 10-Jul-2004 marcel

Implement makectx(). The makectx() function is used by KDB to create
a PCB from a trapframe for purposes of unwinding the stack. The PCB
is used as the thread context and all but the thread that entered the
debugger has a valid PCB.
This function can also be used to create a context for the threads
running on the CPUs that have been stopped when the debugger got
entered. This however is not done at the time of this commit.


# 130722 19-Jun-2004 bde

Removed foot-shooting setting of CR0_TS in exec_setregs(). It is
unnecessary because cpu_setregs() and/or npxinit() always sets CR0_TS
during system initialization, and CR0_TS is set in the next statement
(fpstate_drop()) if necessary after system initialization. Setting
it unnecessarily was less than a pessimization since it broke the
invariant that the npx can be used without an npxdna() trap if
fpucurthread is non-null. The broken invariant became harmful when I
added an fnclex to npxdrop().

Removed setting of CR0_MP in exec_setregs(). This was similarly
unnecessary but was harmless.

Updated comments (mainly by removing them). Things are simpler now
that we have cpu_setregs() and don't support a math emulator or pretend
to support not having either a math emulator or an npx.

Removed the ifdef for avoiding setting CR0_NE in the !SMP case in
cpu_setregs(). npx_probe() should reverse the setting if it wants to
force IRQ13 exception handling for testing.


# 130585 16-Jun-2004 phk

Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.


# 130344 11-Jun-2004 phk

Deorbit COMPAT_SUNOS.

We inherited this from the sparc32 port of BSD4.4-Lite1. We have neither
a sparc32 port nor a SunOS4.x compatibility desire these days.


# 130312 10-Jun-2004 jhb

Remove atdevbase and replace it's remaining uses with direct references to
KERNBASE instead.


# 129097 10-May-2004 jhb

Rework the APIC mixed mode support a bit:
- Require the APIC enumerators to explicitly enable mixed mode by calling
ioapic_enable_mixed_mode(). Calling this function tells the apic driver
that the PC-AT 8259A PICs are present and routable through the first I/O
APIC via an ExtINT pin. The mptable enumerator always calls this
function for now. The MADT enumerator only enables mixed mode if the
PC-AT compatability flag is set in the MADT header.
- Allow mixed mode to be enabled or disabled via a 'hw.apic.mixed_mode'
tunable. By default this tunable is set to 1 (true). The kernel option
NO_MIXED_MODE changes the default to 0 to preserve existing behavior, but
adding 'hw.apic.mixed_mode=0' to loader.conf achieves the same effect.
- Only use mixed mode to route IRQ 0 if it is both enabled by the APIC
enumerator and activated by the loader tunable. Note that both
conditions must be true, so if the APIC enumerator does not enable mixed
mode, then you can't set the tunable to try to override the enumerator.


# 128958 05-May-2004 mux

Unbreak kernel build in the !apic case. We moved to using enums for
setting the polarity and the trigger mode of interrupts.

Tested by: Mark Santcroos, Russell Jackson, Christian Hiris


# 125361 02-Feb-2004 jhb

Set PCPU_GET(curpcb) for the BSP to thread0's pcb. Otherwise, the boot CPU
doesn't have a pcb until after it's first context switch. This can cause
secondary panics if a page fault happens during bootup.


# 124092 03-Jan-2004 davidxu

Make sigaltstack as per-threaded, because per-process sigaltstack state
is useless for threaded programs, multiple threads can not share same
stack.
The alternative signal stack is private for thread, no lock is needed,
the orignal P_ALTSTACK is now moved into td_pflags and renamed to
TDP_ALTSTACK.
For single thread or Linux clone() based threaded program, there is no
semantic changed, because those programs only have one kernel thread
in every process.

Reviewed by: deischen, dfr


# 123135 03-Dec-2003 jhb

- Remove the hack to prevent the acpi module from loading.
- Add a really, really, nasty hack to provide stub versions of all of
the 'device apic' functions used by the ACPI MADT APIC enumerator if
'device apic' is not compiled into the kernel. This is gross but is
the best we can do with the current kernel linker implementation.

Approved by: re (scottl / blanket)


# 122931 20-Nov-2003 peter

MFamd64: use a less compiler-intensive MD implementation of 'curthread'
so that the compiler doesn't have to do so much work.

Approved by: re (jhb)


# 122688 14-Nov-2003 jhb

Fix a typo. We need opt_acpi.h not opt_apic.h for DEV_ACPI.


# 122364 09-Nov-2003 marcel

Change the clear_ret argument of get_mcontext() to be a flags argument.
Since all callers either passed 0 or 1 for clear_ret, define bit 0 in
the flags for use as clear_ret. Reserve bits 1, 2 and 3 for use by MI
code for possible (but unlikely) future use. The remaining bits are for
use by MD code.

This change is triggered by a need on ia64 to have another knob for
get_mcontext().


# 121996 03-Nov-2003 jhb

New i386 SMP code:

- The MP code no longer knows anything specific about an MP Table.
Instead, the local APIC code adds CPUs via the cpu_add() function when
a local APIC is enumerated by an APIC enumerator.
- Don't divide the argument to mp_bootaddress() by 1024 just so that we
can turn around and mulitply it by 1024 again.
- We no longer panic if SMP is enabled but we are booted on a UP machine.
- init_secondary(), the asm code between init_secondary() and ap_init()
in mpboot.s and ap_init() have all been merged together in C into
init_secondary().
- We now use the cpuid feature bits to determine if we should enable
PSE, PGE, or VME on each AP.
- Due to the change in the implementation of critical sections, acquire
the SMP TLB mutex around a slightly larger chunk of code for TLB
shootdowns.
- Remove some of the debug code from the original SMP implementation
that is no longer used or no longer applies to the new APIC code.
- Use a temporary hack to disable the ACPI module until the SMP code has
been further reorganized to allow ACPI to work as a module again.
- Add a DDB command to dump the interesting contents of the IDT.


# 121803 31-Oct-2003 jhb

- Finish externing of r_idt in the f00f hack code.
- Miscellaneous style fixes in the f00f hack code and some nearby code.

Submitted by: bde


# 121754 30-Oct-2003 jhb

Always export r_gdt and r_idt and give them extern declarations in
machine/segments.h.


# 121228 18-Oct-2003 njl

Add the cpu_idle_hook() function pointer so that other idlers can be
hooked at runtime. Make C1 sleep (e.g., HLT) be the default. This
prepares the way for further ACPI sleep states.


# 120992 10-Oct-2003 peter

Set page zero read/write right from the start rather than trying to
change it later on.


# 120975 10-Oct-2003 peter

Move the pmap_kenter(KERNBASE, 0) a bit earlier so that it works for
the hasbrokenint12 tunable case too. (with some related and unrelated
style fixes)

Submitted by: bde


# 120767 04-Oct-2003 peter

Fix the apm problem for real. We leave the first 4K page for the bios to
work in, but we had it mapped read-only. While this has always been the
case, the PG_PS enable hack hid it and the apm bios code ended up taking
advantage of it.


# 120654 01-Oct-2003 peter

Commit Bosko's patch to clean up the PSE/PG_G initialization to and
avoid problems with some Pentium 4 cpus and some older PPro/Pentium2
cpus. There are several problems, some documented in Intel errata.
This patch:
1) moves the kernel to the second page in the PSE case. There is an
errata that says that you Must Not point a 4MB page at physical
address zero on older cpus. We avoided bugs here due to sheer luck.
2) sets up PSE page tables right from the start in locore, rather than
trying to switch from 4K to 4M (or 2M) pages part way through the boot
sequence at the same time that we're messing with PG_G.

For some reason, the pmap work over the last 18 months seems to tickle
the problems, and the PAE infrastructure changes disturb the cpu
bugs even more.

A couple of people have reported a problem with APM bios calls during
boot. I'll work with people to get this resolved.

Obtained from: bmilekic


# 120594 30-Sep-2003 jeff

- Correct a typo in a comment.


# 119935 10-Sep-2003 jhb

Add constants for entries in the IDT and use those instead of magic
numbers.


# 119847 07-Sep-2003 bde

clock.c:
Quick fix for calling DELAY() for ddb input in some (atkbd-based)
console drivers. ddb must not use any normal locks, but DELAY()
normally calls getit() which needs clock_lock. One problem with using
normal locks in ddb is that deadlock is possible, but deadlock on
clock_lock is unlikely becaluse clock_lock is bogusly recursive,
apparently just to hide the problem of ddb using it. The i8254 clock
hardware has mostly write-only registers so it is important for it to
use a lock that gives exclusive access. (atkbd hardware is also
unfriendly to reentrant software but that problem is more local and
already solved.) I mostly saw the symptoms of the bug caused by
unlocking in getit() running cpu_unpend(). cpu_unpend() should not
be called while in ddb and Debugger() calls for failing assertions
about this caused a breakpoint within ddb.

ddb must also not call getit() because ddb may be being used to step
through clock initialization code that has stopped or otherwise mangled
the clock. If the clock is stopped, then getit() always returns the
same value and DELAY() takes forever if it trusts getit().

The quick fix is implement DELAY(n) as (n * timer_freq / 1000000)
inb(0x84)'s if ddb is active.

machdep.c:
Don't permit recursion on clock_lock.


# 118235 31-Jul-2003 peter

Cosmetic: fix disorder of opt_kstack_pages.h include.


# 117600 15-Jul-2003 davidxu

Rename thread_siginfo to cpu_thread_siginfo.

Suggested by: jhb


# 116958 28-Jun-2003 davidxu

Add a machine depended function thread_siginfo, SA signal code
will use the function to construct a siginfo structure and use
the result to export to userland.

Reviewed by: julian


# 116930 27-Jun-2003 peter

Tidy up leftover lazy_switch instrumentation that is no longer needed.
This cleans up some #ifdef hell.


# 115683 02-Jun-2003 obrien

Use __FBSDID().


# 114983 13-May-2003 jhb

- Merge struct procsig with struct sigacts.
- Move struct sigacts out of the u-area and malloc() it using the
M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures: sigacts_alloc(),
sigacts_free(), sigacts_copy(), sigacts_share(), and sigacts_shared().
- Remove the p_sigignore, p_sigacts, and p_sigcatch macros.
- Add a mutex to struct sigacts that protects all the members of the struct.
- Add sigacts locking.
- Remove Giant from nosys(), kill(), killpg(), and kern_sigaction() now
that sigacts is locked.
- Several in-kernel functions such as psignal(), tdsignal(), trapsignal(),
and thread_stopped() are now MP safe.

Reviewed by: arch@
Approved by: re (rwatson)


# 113998 25-Apr-2003 deischen

Add an argument to get_mcontext() which specified whether the
syscall return values should be cleared. The system calls
getcontext() and swapcontext() want to return 0 on success
but these contexts can be switched to at a later time so
the return values need to be cleared in the saved register
sets. Other callers of get_mcontext() would normally want
the context without clearing the return values.

Remove the i386-specific context saving from the KSE code.
get_mcontext() is not i386-specific any more.

Fix a bad pointer in the alpha get_mcontext() code. The
context was being bcopy()'d from &td->tf_frame, but tf_frame
is itself a pointer, so the thread was being copied instead.
Spotted by jake.

Glanced at by: jake
Reviewed by: bde (months ago)


# 113682 18-Apr-2003 jhb

Hold the proc lock for curproc around sigonstack().


# 112993 02-Apr-2003 peter

Commit a partial lazy thread switch mechanism for i386. it isn't as lazy
as it could be and can do with some more cleanup. Currently its under
options LAZY_SWITCH. What this does is avoid %cr3 reloads for short
context switches that do not involve another user process. ie: we can
take an interrupt, switch to a kthread and return to the user without
explicitly flushing the tlb. However, this isn't as exciting as it could
be, the interrupt overhead is still high and too much blocks on Giant
still. There are some debug sysctls, for stats and for an on/off switch.

The main problem with doing this has been "what if the process that you're
running on exits while we're borrowing its address space?" - in this case
we use an IPI to give it a kick when we're about to reclaim the pmap.

Its not compiled in unless you add the LAZY_SWITCH option. I want to fix a
few more things and get some more feedback before turning it on by default.

This is NOT a replacement for Bosko's lazy interrupt stuff. This was more
meant for the kthread case, while his was for interrupts. Mine helps a
little for interrupts, but his helps a lot more.

The stats are enabled with options SWTCH_OPTIM_STATS - this has been a
pseudo-option for years, I just added a bunch of stuff to it.

One non-trivial change was to select a new thread before calling
cpu_switch() in the first place. This allows us to catch the silly
case of doing a cpu_switch() to the current process. This happens
uncomfortably often. This simplifies a bit of the asm code in cpu_switch
(no longer have to call choosethread() in the middle). This has been
implemented on i386 and (thanks to jake) sparc64. The others will come
soon. This is actually seperate to the lazy switch stuff.

Glanced at by: jake, jhb


# 112888 31-Mar-2003 jeff

- Move p->p_sigmask to td->td_sigmask. Signal masks will be per thread with
a follow on commit to kern_sig.c
- signotify() now operates on a thread since unmasked pending signals are
stored in the thread.
- PS_NEEDSIGCHK moves to TDF_NEEDSIGCHK.


# 112883 31-Mar-2003 jeff

- Change trapsignal() to accept a thread and not a proc.
- Change all consumers to pass in a thread.

Right now this does not cause any functional changes but it will be important
later when signals can be delivered to specific threads.


# 112841 30-Mar-2003 jake

- Add support for PAE and more than 4 gigs of ram on x86, dependent on the
kernel opition 'options PAE'. This will only work with device drivers which
either use busdma, or are able to handle 64 bit physical addresses.

Thanks to Lanny Baron from FreeBSD Systems for the loan of a test machine
with 6 gigs of ram.

Sponsored by: DARPA, Network Associates Laboratories, FreeBSD Systems


# 112687 26-Mar-2003 ps

Nuke options HTT infavor of machdep.hlt_logical_cpus tunable/sysctl.
This keeps the logical cpu's halted in the idle loop. By default
the logical cpu's are halted at startup. It is also possible to
halt any cpu in the idle loop now using machdep.hlt_cpus.

Examples of how to use this:
machdep.hlt_cpus=1 halt cpu0
machdep.hlt_cpus=2 halt cpu1
machdep.hlt_cpus=4 halt cpu2
machdep.hlt_cpus=3 halt cpu0,cpu1

Reviewed by: jhb, peter


# 112686 26-Mar-2003 peter

Halt the cpus in the idle loop for SMP as well for several reasons:
1) Its critical for HTT. There's less foot-shooting opportunity.
2) I've seen significant improvements in interactive response to commands
over ssh sessions. I assume this is less lock contention.
3) As incentive to finish the idle cpu IPI wakeup stuff.
4) The machine on my desk was blowing hot air in my general direction
because somebody forgot to turn the hlt on, and it saves 50 watts per
cpu..

The machdep.cpu_idle_hlt sysctl is still available, but now the default
is the same as on UP kernels.


# 112569 25-Mar-2003 jake

- Add vm_paddr_t, a physical address type. This is required for systems
where physical addresses larger than virtual addresses, such as i386s
with PAE.
- Use this to represent physical addresses in the MI vm system and in the
i386 pmap code. This also changes the paddr parameter to d_mmap_t.
- Fix printf formats to handle physical addresses >4G in the i386 memory
detection code, and due to kvtop returning vm_paddr_t instead of u_long.

Note that this is a name change only; vm_paddr_t is still the same as
vm_offset_t on all currently supported platforms.

Sponsored by: DARPA, Network Associates Laboratories
Discussed with: re, phk (cdevsw change)


# 111167 20-Feb-2003 peter

Fix fumble in rev 1.525. pmap_kenter()'s second argument is a physical
address, not a page index.

Laughed at by: jake


# 109994 28-Jan-2003 jake

Remove BDE_DEBUGGER.

Discussed with: bde


# 109027 09-Jan-2003 jhb

Remove earlysetcpuclass() as it has been OBE.

Suggested by: bde


# 107521 02-Dec-2002 deischen

Align the FPU state in the ucontext and sigcontext to 16 bytes
to accomodate the new SSE/XMM floating point save/restore
instructions.

This commit is mostly from bde and includes some style nits.

Approved by: re (jhb)


# 106977 16-Nov-2002 deischen

Add getcontext, setcontext, and swapcontext as system calls.
Previously these were libc functions but were requested to
be made into system calls for atomicity and to coalesce what
might be two entrances into the kernel (signal mask setting
and floating point trap) into one.

A few style nits and comments from bde are also included.

Tested on alpha by: gallatin


# 106707 09-Nov-2002 iwasaki

Add a new loader tunable, hw.hasbrokenint12, to indicate that BIOS
has broken int 12H.
If hw.hasbrokenint12="1" in loader environment, kernel never use BIOS
INT 12 call to determine base memory size.
Otherwise, kernel use INT 12 in old behaviour.
This should fix kernel panic problem caused by 1.544 changes.

MFC after: 1 day


# 106697 09-Nov-2002 des

Print real / avail memory in megabytes rather than kilobytes.


# 106605 07-Nov-2002 tmm

Move the definitions of the hw.physmem, hw.usermem and hw.availpages
sysctls to MI code; this reduces code duplication and makes all of them
available on sparc64, and the latter two on powerpc.
The semantics by the i386 and pc98 hw.availpages is slightly changed:
previously, holes between ranges of available pages would be included,
while they are excluded now. The new behaviour should be more correct
and brings i386 in line with the other architectures.

Move physmem to vm/vm_init.c, where this variable is used in MI code.


# 106503 06-Nov-2002 jmallett

Remove what was a temporary bogus assignment of bits of siginfo_t, as it does
not look like the prerequisites to fill it in properly will be in the tree
for the upcoming release, but it's mostly done, so there is no need for these
to stay around to remind us.


# 105950 25-Oct-2002 peter

Split 4.x and 5.x signal handling so that we can keep 4.x signal
handling clean and functional as 5.x evolves. This allows some of the
nasty bandaids in the 5.x codepaths to be unwound.

Encapsulate 4.x signal handling under COMPAT_FREEBSD4 (there is an
anti-foot-shooting measure in place, 5.x folks need this for a while) and
finish encapsulating the older stuff under COMPAT_43. Since the ancient
stuff is required on alpha (longjmp(3) passes a 'struct osigcontext *'
to the current sigreturn(2), instead of the 'ucontext_t *' that sigreturn
is supposed to take), add a compile time check to prevent foot shooting
there too. Add uniform COMPAT_43 stubs for ia64/sparc64/powerpc.

Tested on: i386, alpha, ia64. Compiled on sparc64 (a few days ago).
Approved by: re


# 105949 25-Oct-2002 iwasaki

Change method to determine base memory size.
Try INT 15H/E820H first, then fall back to the old compatibility
method (INT 12H).
This is a workaround for newer machines which have broken INT 12H BIOS
service implementation.

Reviewed by: -current ML
MFC after: 3 days


# 105554 20-Oct-2002 phk

Change the definition of the debugging registers to be an array, so
that we can index into it, rather than do pointer gymnastics on a
structure containing 8 elements.

Verified by: MD5 hash on the produced .o files.


# 104964 12-Oct-2002 jeff

- Create a new scheduler api that is defined in sys/sched.h
- Begin moving scheduler specific functionality into sched_4bsd.c
- Replace direct manipulation of scheduler data with hooks provided by the
new api.
- Remove KSE specific state modifications and single runq assumptions from
kern_switch.c

Reviewed by: -arch


# 104513 05-Oct-2002 deischen

Fix building of minimal kernels without npx by rearranging ifdefs.
Also fix some style bugs in surrounding code, and add a comment
about FP state restoral that seems questionable.

Submitted by: bde


# 104460 04-Oct-2002 deischen

Add another temporary hack to allow running older i386 binaries.
This will be removed when new versions of syscalls sigreturn()
and sigaction() are added (mini is working on this but is in
the middle of a move).

This should fix the problem of cvsupd dying.


# 104174 30-Sep-2002 obrien

Save the FP state in the PCB as that is compatable with releng4 binaries.

This is a band-aid until the KSE pthread committers get back on the ground
and have their machines setup.

Submitted by: eischen


# 103772 22-Sep-2002 mdodd

- Move the init of %gs and pcb_gs before user_ldt_free().
- Always call load_gs()
- Trim comments.

This addresses some of the issues raised by BDE.


# 103703 20-Sep-2002 phk

For reasons now lost in historical fog, the bounds_check_with_label()
function were put in i386/i386/machdep.c from where it has been
cut and pasted to other architectures with only minor corruption.

Disklabel is really a MI format in many ways, at least it certainly
is when you operate on struct disklabel.

Put bounds_check_with_label() back in subr_disklabel.c where it belongs.

Sponsored by: DARPA & NAI Labs.


# 103645 19-Sep-2002 mdodd

From Christian Zander:

This patch addresses a bug that can cause a GPF in the kernel - if a
process makes use of i386_set_ldt to install a LDT entry, then loads
a corresponding segment descriptor into %gs, forks, and if the child
execs.

In this scenario, setregs executes user_ldt_free and then determines
how to reset the %gs register:

/* reset %gs as well */
if (pcb == curpcb)
load_gs(_udatasel);
else
pcb->pcb_gs = _udatasel;

This is insufficient in the fork/exec case, since pcb will be equal
to curpcb when the child execs; load_gs will reset %gs to _udatasel
but it doesn't reset pcb->pcb_gs; upon return from the system call,
cpu_switch_load_gs will thus attempt to restore %gs from pcb->pcb_gs
and trigger a GPF since all LDT entries have already been cleared.

The fix is to always reset pcb->pcb_gs to _udatasel.

Submitted by: Christian Zander <zander@minion.de>
Reviewed by: jake


# 103477 17-Sep-2002 sobomax

Don't reference cpu_fxsr unless CPU_ENABLE_SSE is defined. This fixes kernel
in !CPU_ENABLE_SSE case.


# 103407 16-Sep-2002 mini

Add kernel support needed for the KSE-aware libpthread:
- Maintain fpu state across signals.
- Use ucontext_t's to store KSE thread state.
- Synthesize state for the UTS upon each upcall, rather than
saving and copying a trapframe.
- Save and restore FPU state properly in ucontext_t's.

Reviewed by: deischen, julian
Approved by: -arch


# 103367 15-Sep-2002 julian

Allocate KSEs and KSEGRPs separatly and remove them from the proc structure.
next step is to allow > 1 to be allocated per process. This would give
multi-processor threads. (when the rest of the infrastructure is
in place)

While doing this I noticed libkvm and sys/kern/kern_proc.c:fill_kinfo_proc
are diverging more than they should.. corrective action needed soon.


# 103081 07-Sep-2002 jmallett

Fill out two fields (si_pid, si_uid) in the siginfo structure handed back
to userland in the signal handler that were not being iflled out before, but
should and can be.

This part of sendsig could be slightly refactored to use an MI interface, or
ideally, *sendsig*() would have an API change to accept a siginfo_t, which
would be filled out by an MI function in the level above sendsig, and said MI
function would make a small call into MD code to fill out the MD parts (some
of which may be bogus, such as the si_addr stuff in some places). This would
eventually make it possible for parts of the kernel sending signals to set up
a siginfo with meaningful information.

Reviewed by: mux
MFC after: 2 weeks


# 103076 07-Sep-2002 jmallett

Match the more modern ports and comment the filling of POSIX parts of siginfo
with 'Fill in POSIX parts'. (Diff reduction.)


# 103064 07-Sep-2002 peter

Automatically enable CPU_ENABLE_SSE (detect and enable SSE instructions)
if compiling with I686_CPU as a target. CPU_DISABLE_SSE will prevent
this from happening and will guarantee the code is not compiled in.

I am still not happy with this, but gcc is now generating code that uses
these instructions if you set CPUTYPE to p3/p4 or athlon-4/mp/xp or higher.


# 102666 31-Aug-2002 peter

Take a shot at fixing up a whole stack of style and other embarresing
unforced errors that Bruce identified. I have not yet addressed all of
his concerns.


# 102603 30-Aug-2002 ache

Unbreak kernel build by printing Maxmem using %ld instead of old (now changed)
%u


# 102600 30-Aug-2002 peter

Change hw.physmem and hw.usermem to unsigned long like they used to be
in the original hardwired sysctl implementation.

The buf size calculator still overflows an integer on machines with large
KVA (eg: ia64) where the number of pages does not fit into an int. Use
'long' there.

Change Maxmem and physmem and related variables to 'long', mostly for
completeness. Machines are not likely to overflow 'int' pages in the
near term, but then again, 640K ought to be enough for anybody. This
comes for free on 32 bit machines, so why not?


# 102561 29-Aug-2002 jake

Renamed poorly named setregs to exec_setregs. Moved its prototype to
imgact.h with the other exec support functions.


# 100275 18-Jul-2002 peter

Use pmap_kenter() rather than vtopte() and bashing the page tables
directly.


# 100220 17-Jul-2002 dillon

Qualify comment on machdep.cpu_idle_hlt. Turning this on on a SMP
machine will result in approximately a 4.2% loss of performance (buildworld)
and approximately a 5% reduction in power consumption (when idle). Add XXX
note on how to really make hlt work (send an IPI to wakeup HLTed cpus on
a thread-schedule event? Generate an interrupt somehow?).


# 99567 08-Jul-2002 peter

s/procrunnable/kserunnable/ in a comment


# 99537 07-Jul-2002 mux

One #include <sys/lock.h> is enough.

Submitted by: Olivier Houchard <cognet@ci0.org>


# 99072 29-Jun-2002 julian

Part 1 of KSE-III

The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)

Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)

NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..


# 98778 24-Jun-2002 peter

Compile in the cpu halt code even on SMP, instead just default the
sysctl (machdep.cpu_idle_hlt) to off in the SMP case. This allows you to
turn it on if you wish and do not particularly care about the small window
where a cpu will remain halted even when a job is placed on the run queue
(until the next clock tick).


# 96517 13-May-2002 bde

Fixed a syntax error (a label not followed by a statement).


# 94936 17-Apr-2002 mux

Rework the kernel environment subsystem. We now convert the static
environment needed at boot time to a dynamic subsystem when VM is
up. The dynamic kernel environment is protected by an sx lock.

This adds some new functions to manipulate the kernel environment :
freeenv(), setenv(), unsetenv() and testenv(). freeenv() has to be
called after every getenv() when you have finished using the string.
testenv() only tests if an environment variable is present, and
doesn't require a freeenv() call. setenv() and unsetenv() are self
explanatory.

The kenv(2) syscall exports these new functionalities to userland,
mainly for kenv(1).

Reviewed by: peter


# 94383 10-Apr-2002 alc

o In osigreturn(), restore all of the registers in one place.
o Recent changes to osigreturn() and sigreturn() have made them MPSAFE. Add
a comment to this effect.

Submitted by: bde (bullet #1)
Reviewed by: jhb (bullet #2)


# 94275 09-Apr-2002 phk

GC various bits and pieces of USERCONFIG from all over the place.


# 94197 08-Apr-2002 bde

Removed ispc98 sysctl completely. Applications should understand that
ispc98 isn't set if its sysctl doesn't exist. At least make(1) already
understands this.

Approved by: nyan


# 94151 07-Apr-2002 phk

GC the "dumplo" variable, which is no longer used.

A lot of sys/*/*/machdep.c seems not to be.


# 93944 06-Apr-2002 nyan

Remove pc98 code.


# 93818 04-Apr-2002 jhb

Change callers of mtx_init() to pass in an appropriate lock type name. In
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.

Tested on: i386, alpha, sparc64


# 93793 04-Apr-2002 bde

Moved signal handling and rescheduling from userret() to ast() so that
they aren't in the usual path of execution for syscalls and traps.
The main complication for this is that we have to set flags to control
ast() everywhere that changes the signal mask.

Avoid locking in userret() in most of the remaining cases.

Submitted by: luoqi (first part only, long ago, reorganized by me)
Reminded by: dillon


# 93702 02-Apr-2002 jhb

- Move the MI mutexes sched_lock and Giant from being declared in the
various machdep.c's to being declared in kern_mutex.c.
- Add a new function mutex_init() used to perform early initialization
needed for mutexes such as setting up thread0's contested lock list
and initializing MI mutexes. Change the various MD startup routines
to call this function instead of duplicating all the code themselves.

Tested on: alpha, i386


# 93593 01-Apr-2002 jhb

Change the suser() API to take advantage of td_ucred as well as do a
general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.

Discussed on: smp@


# 93461 31-Mar-2002 alc

Implement i386's (o)sigreturn() like the alpha's: Use copyin() to read
the osigcontext or ucontext_t rather than useracc() followed by direct user-
space memory accesses. This reduces (o)sigreturn()'s execution time by 5-
50%.

Submitted by: bde


# 93273 27-Mar-2002 jeff

Add a new mtx_init option "MTX_DUPOK" which allows duplicate acquires of locks
with this flag. Remove the dup_list and dup_ok code from subr_witness. Now
we just check for the flag instead of doing string compares.

Also, switch the process lock, process group lock, and uma per cpu locks over
to this interface. The original mechanism did not work well for uma because
per cpu lock names are unique to each zone.

Approved by: jhb


# 93264 27-Mar-2002 dillon

Compromise for critical*()/cpu_critical*() recommit. Cleanup the interrupt
disablement assumptions in kern_fork.c by adding another API call,
cpu_critical_fork_exit(). Cleanup the td_savecrit field by moving it
from MI to MD. Temporarily move cpu_critical*() from <arch>/include/cpufunc.h
to <arch>/<arch>/critical.c (stage-2 will clean this up).

Implement interrupt deferral for i386 that allows interrupts to remain
enabled inside critical sections. This also fixes an IPI interlock bug,
and requires uses of icu_lock to be enclosed in a true interrupt disablement.

This is the stage-1 commit. Stage-2 will occur after stage-1 has stabilized,
and will move cpu_critical*() into its own header file(s) + other things.
This commit may break non-i386 architectures in trivial ways. This should
be temporary.

Reviewed by: core
Approved by: core


# 92770 20-Mar-2002 alfred

Remove __P.


# 92548 18-Mar-2002 alc

Eliminate grow_stack() from (o)sendsig(). If the stack needs to grow,
copyout() will page fault and perform grow_stack() from trap_pfault().
These calls to grow_stack() accomplish nothing.

Reviewed by: bde


# 92470 17-Mar-2002 alc

o Stop calling useracc() in (o)sendsig() now that we use copyout()
to copy the sigframe to the user's stack. Useracc() takes a non-trivial
amount of time. Eliminating it speeds up signal delivery by 15% or more.
o Update some comments.

Submitted by: bde


# 92018 10-Mar-2002 luigi

Export a (machine dependent) kernel variable bootdev as
machdep.guessed_bootdev, and add code to sysctl to parse its value
and give a (not necessarily correct) name to the device we booted
from (the main motivation for this code is to use the info in the
PicoBSD boot scripts, and the impact on the kernel is minimal).

NOTE: the information available in bootdev is not always reliable,
so you should not trust it too much. The parsing code is the same
as in boot2.c, and cannot cover all cases -- as it is, it seems to
work fine with floppies and IDE disks recognised by the BIOS. It
_should_ work as well with SCSI disks recognised by the BIOS.
Booting from a CDROM in floppy emulation will return /dev/fd0 (because
this is what the BIOS tells us).
Booting off the network (e.g. with etherboot) leaves bootdev unset so
the value will be printed as "invalid (0xffffffff)".

Finally, this feature might go away at some point, hopefully when we
have a more reliable way to get the same information.

MFC-after: 5 days


# 91893 08-Mar-2002 phk

#include <machine/smp.h> in the SMP case.
don't include <sys/smp.h> at all.

Fallout from: probably something jake did.
Hint by: jhb


# 91328 26-Feb-2002 dillon

revert last commit temporarily due to whining on the lists.


# 91315 26-Feb-2002 dillon

STAGE-1 of 3 commit - allow (but do not require) interrupts to remain
enabled in critical sections and streamline critical_enter() and
critical_exit().

This commit allows an architecture to leave interrupts enabled inside
critical sections if it so wishes. Architectures that do not wish to do
this are not effected by this change.

This commit implements the feature for the I386 architecture and provides
a sysctl, debug.critical_mode, which defaults to 1 (use the feature). For
now you can turn the sysctl on and off at any time in order to test the
architectural changes or track down bugs.

This commit is just the first stage. Some areas of the code, specifically
the MACHINE_CRITICAL_ENTER #ifdef'd code, is strictly temporary and will
be cleaned up in the STAGE-2 commit when the critical_*() functions are
moved entirely into MD files.

The following changes have been made:

* critical_enter() and critical_exit() for I386 now simply increment
and decrement curthread->td_critnest. They no longer disable
hard interrupts. When critical_exit() decrements the counter to
0 it effectively calls a routine to deal with whatever interrupts
were deferred during the time the code was operating in a critical
section.

Other architectures are unaffected.

* fork_exit() has been conditionalized to remove MD assumptions for
the new code. Old code will still use the old MD assumptions
in regards to hard interrupt disablement. In STAGE-2 this will
be turned into a subroutine call into MD code rather then hardcoded
in MI code.

The new code places the burden of entering the critical section
in the trampoline code where it belongs.

* I386: interrupts are now enabled while we are in a critical section.
The interrupt vector code has been adjusted to deal with the fact.
If it detects that we are in a critical section it currently defers
the interrupt by adding the appropriate bit to an interrupt mask.

* In order to accomplish the deferral, icu_lock is required. This
is i386-specific. Thus icu_lock can only be obtained by mainline
i386 code while interrupts are hard disabled. This change has been
made.

* Because interrupts may or may not be hard disabled during a
context switch, cpu_switch() can no longer simply assume that
PSL_I will be in a consistent state. Therefore, it now saves and
restores eflags.

* FAST INTERRUPT PROVISION. Fast interrupts are currently deferred.
The intention is to eventually allow them to operate either while
we are in a critical section or, if we are able to restrict the
use of sched_lock, while we are not holding the sched_lock.

* ICU and APIC vector assembly for I386 cleaned up. The ICU code
has been cleaned up to match the APIC code in regards to format
and macro availability. Additionally, the code has been adjusted
to deal with deferred interrupts.

* Deferred interrupts use a per-cpu boolean int_pending, and
masks ipending, spending, and fpending. Being per-cpu variables
it is not currently necessary to lock; bus cycles modifying them.

Note that the same mechanism will enable preemption to be
incorporated as a true software interrupt without having to
further hack up the critical nesting code.

* Note: the old critical_enter() code in kern/kern_switch.c is
currently #ifdef to be compatible with both the old and new
methodology. In STAGE-2 it will be moved entirely to MD code.

Performance issues:

One of the purposes of this commit is to enhance critical section
performance, specifically to greatly reduce bus overhead to allow
the critical section code to be used to protect per-cpu caches.
These caches, such as Jeff's slab allocator work, can potentially
operate very quickly making the effective savings of the new
critical section code's performance very significant.

The second purpose of this commit is to allow architectures to
enable certain interrupts while in a critical section. Specifically,
the intention is to eventually allow certain FAST interrupts to
operate rather then defer.

The third purpose of this commit is to begin to clean up the
critical_enter()/critical_exit()/cpu_critical_enter()/
cpu_critical_exit() API which currently has serious cross pollution
in MI code (in fork_exit() and ast() for example).

The fourth purpose of this commit is to provide a framework that
allows kernel-preempting software interrupts to be implemented
cleanly. This is currently used for two forward interrupts in I386.
Other architectures will have the choice of using this infrastructure
or building the functionality directly into critical_enter()/
critical_exit().

Finally, this commit is designed to greatly improve the flexibility
of various architectures to manage critical section handling,
software interrupts, preemption, and other highly integrated
architecture-specific details.


# 91262 26-Feb-2002 peter

Fix a warning. useracc() should take a const pointer argument.


# 90776 17-Feb-2002 deischen

Use struct __ucontext in prototypes and associated functions instead of
ucontext_t. Forward declare struct __ucontext in <sys/signal.h> and
remove reliance on <sys/ucontext.h> being included.

While I'm here, also hide osigcontext types from userland; suggested
by bde.

Namespace pollution noticed by: Kevin Day <toasty@shell.dragondata.com>


# 90718 16-Feb-2002 bde

Don't leave garbage in parts of fpregs in the fxsr case. All callers
(procfs and ptrace) supply kernel stack garbage, so kernel context was
leaked to userland.

Reviewed by: des


# 90633 13-Feb-2002 bde

Don't confuse a struct with its first member. This fixes:
./@/i386/i386/machdep.c: In function `init386':
./@/i386/i386/machdep.c:1700: warning: assignment from incompatible pointer type


# 90372 07-Feb-2002 peter

Attempt to patch up some style bugs introduced in the previous commit


# 90361 07-Feb-2002 julian

Pre-KSE/M3 commit.
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.

Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,


# 90132 03-Feb-2002 bde

Use osigreturn(2) instead of sigreturn(2) plus broken magic for returning
from old signal handlers. This is simpler and faster, and fixes (new)
sigreturn(2) when %eip in the new signal context happens to match the
magic value (0x1d516). 0x1d516 is below the default ELF text section,
so this probably never broken anything in practice.

locore.s:
In addition, don't build the signal trampoline for old signal handlers
when it is not used.

alpha:
Not fixed, but seems to be even less broken in practice due to more
advanced magic. A false match occurs for register #32 in mc_regs[].
Since there is no hardware register #32, a false match is only possible
for direct calls to sigreturn(2) that happen to have the magic number
in the spare mc_regs[32] field.


# 90128 03-Feb-2002 bde

Improve the change in the previous commit: use a stub for osigreturn()
when it is not really used instead of unconditionalizing all of it.


# 90065 01-Feb-2002 bde

Compile osigreturn() unconditionally since it will always be needed on
some arches and the syscall table is machine-independent. It was
(bogusly) conditional on COMPAT_43, so this usually makes no difference.

ia64: in addition:
- replace the bogus cloned comment before osigreturn() by a correct one.
osigreturn() is just a stub fo ia64's.
- fix the formatting of cloned comment before sigreturn().
- fix the return code. use nosys() instead of returning ENOSYS to get
the same semantics as if the syscall is not in the syscall table.
Generating SIGSYS is actually correct here.
- fix style bugs.

powerpc: copy the cleaned up ia64 stub. This mainly fixes a bogus comment.

sparc64: copy the cleaned up the ia64 stub, since there was no stub before.


# 89988 30-Jan-2002 bde

Cleaned up the 0ldSiG magic check before removing it. Just use fuword()
to fetch the magic word instead of useracc() plus a direct access.
This is more efficient as well as simpler and less incorrect:
- it was inefficent because useracc() takes much longer than just
accessing the data using a correct access method, at least on i386's.
- it was incorrect because direct access is incorrect unless the address
has been mapped. This and nearby direct accesses are mostly handled
better for other arches because they have to be (direct accesses don't
work).
- using magic in sigreturn is still fundamentally broken because false
matches are possible. On i386's, a false match occurs when %eip in a
new signal context happens to equal the magic value. This is not
handled better for other arches.


# 89195 10-Jan-2002 bde

Clear the single-step flag for signal handlers. This fixes bogus trace
traps on the first instruction of signal handlers.

In trap.c:syscall(), fake a trace trap if the single-step flag was set
on entry to the kernel, not if it will be set on exit from the kernel.
This fixes bogus trace traps after the last instruction of signal handlers.

gdb-4.18 (the version in FreeBSD) still has problems with the program in
the PR. These seem to be due to bugs in gdb and not in FreeBSD, and are
fixed in gdb-5.1 (the distribution version).

PR: 33262
Tested by: k Macy <kip_macy@yahoo.com>
MFC after: 1 day


# 89175 10-Jan-2002 deischen

Use a spare slot in the machine context for a flags word to indicate
whether the machine context is valid and whether the FPU state is
valid (saved).

Mark the machine context valid before copying it out when sending a
signal.

Approved by: -arch


# 88322 20-Dec-2001 jhb

Introduce a standard name for the lock protecting an interrupt controller
and it's associated state variables: icu_lock with the name "icu". This
renames the imen_mtx for x86 SMP, but also uses the lock to protect
access to the 8259 PIC on x86 UP. This also adds an appropriate lock to
the various Alpha chipsets which fixes problems with Alpha SMP machines
dropping interrupts with an SMP kernel.


# 87702 11-Dec-2001 jhb

Overhaul the per-CPU support a bit:

- The MI portions of struct globaldata have been consolidated into a MI
struct pcpu. The MD per-CPU data are specified via a macro defined in
machine/pcpu.h. A macro was chosen over a struct mdpcpu so that the
interface would be cleaner (PCPU_GET(my_md_field) vs.
PCPU_GET(md.md_my_md_field)).
- All references to globaldata are changed to pcpu instead. In a UP kernel,
this data was stored as global variables which is where the original name
came from. In an SMP world this data is per-CPU and ideally private to each
CPU outside of the context of debuggers. This also included combining
machine/globaldata.h and machine/globals.h into machine/pcpu.h.
- The pointer to the thread using the FPU on i386 was renamed from
npxthread to fpcurthread to be identical with other architectures.
- Make the show pcpu ddb command MI with a MD callout to display MD
fields.
- The globaldata_register() function was renamed to pcpu_init() and now
init's MI fields of a struct pcpu in addition to registering it with
the internal array and list.
- A pcpu_destroy() function was added to remove a struct pcpu from the
internal array and list.

Tested on: alpha, i386
Reviewed by: peter, jake


# 87546 09-Dec-2001 dillon

Allow maxusers to be specified as 0 in the kernel config, which will
cause the system to auto-size to between 32 and 512 depending on the
amount of memory.

MFC after: 1 week


# 86485 17-Nov-2001 peter

Start bringing i386/pmap.c into line with cleanups that were done to
alpha pmap. In particular -
- pd_entry_t and pt_entry_t are now u_int32_t instead of a pointer.
This is to enable cleaner PAE and x86-64 support down the track sor
that we can change the pd_entry_t/pt_entry_t types to 64 bit entities.
- Terminate "unsigned *ptep, pte" with extreme prejudice and use the
correct pt_entry_t/pd_entry_t types.
- Various other cosmetic changes to match cleanups elsewhere.
- This eliminates a boatload of casts.
- use VM_MAXUSER_ADDRESS in place of UPT_MIN_ADDRESS in a couple of places
where we're testing user address space limits. Assuming the page tables
start directly after the end of user space is not a safe assumption.
There is still more to go.


# 85695 29-Oct-2001 bde

Don't set CR0_NE in cpu_setregs() for the SMP case, since setting it
is npx.c's job and setting it here breaks the edit-time option of not
setting it in npx.c. (It is not set in the right places for the SMP
case, but always setting it here is harmless because there isn't even
an edit-time option to not set it.)


# 85449 25-Oct-2001 jhb

Split the per-process Local Descriptor Table out of the PCB and into
struct mdproc.

Submitted by: Andrew R. Reiter <arr@watson.org>
Silence on: -current


# 83366 12-Sep-2001 julian

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha


# 83163 06-Sep-2001 jhb

Call sendsig() with the proc lock held and return with it held.


# 82939 04-Sep-2001 peter

Zap #if 0'ed map init code that got moved to the MI area.
Convert the powerpc tree to use the common code.


# 82393 27-Aug-2001 peter

Enable hardwiring of things like tunables from embedded enironments
that do not start from loader(8).


# 82309 25-Aug-2001 peter

Optionize UPAGES for the i386. As part of this I split some of the low
level implementation stuff out of machine/globaldata.h to avoid exposing
UPAGES to lots more places. The end result is that we can double
the kernel stack size with 'options UPAGES=4' etc.

This is mainly being done for the benefit of a MFC to RELENG_4 at some
point. -current doesn't really need this so much since each interrupt
runs on its own kstack.


# 82165 23-Aug-2001 peter

Fix a comment error that was fixed in the pc98 version. hw.maxmem is
really hw.physmem.


# 82157 23-Aug-2001 peter

Dont add UPAGES to the %cs segment limit. There is nothing there except
page tables.


# 82127 22-Aug-2001 dillon

Move most of the kernel submap initialization code, including the
timeout callwheel and buffer cache, out of the platform specific areas
and into the machine independant area. i386 and alpha adjusted here.
Other cpus can be fixed piecemeal.

Reviewed by: freebsd-smp, jake


# 82031 21-Aug-2001 dillon

Fix bug in physmem_est calculation - the kernel_map size was not being
converted into pages.

Fix bug in maxbcache calculation, nbuf must be tested against maxbcache
rather then physmem_est.

Obtained from: bde


# 82025 21-Aug-2001 peter

Make COMPAT_43 optional again. XXX we need COMPAT_FBSD3 etc for this
stuff.


# 81933 20-Aug-2001 dillon

Limit the amount of KVM reserved for the buffer cache and for swap-meta
information. The default limits only effect machines with > 1GB of ram
and can be overriden with two new kernel conf variables VM_SWZONE_SIZE_MAX
and VM_BCACHE_SIZE_MAX, or with loader variables kern.maxswzone and
kern.maxbcache. This has the effect of leaving more KVM available for
sizing NMBCLUSTERS and 'maxusers' and should avoid tripups where a sysad
adds memory to a machine and then sees the kernel panic on boot due to
running out of KVM.

Also change the default swap-meta auto-sizing calculation to allocate half
of what it was previously allocating. The prior defaults were way too high.
Note that we cannot afford to run out of swap-meta structures so we still
stay somewhat conservative here.


# 81704 15-Aug-2001 jhb

Whitespace fixes to make this mostly fit in 80 columns.


# 81584 13-Aug-2001 bde

Use interrupt gates instead of trap gates for breakpoint and trace
traps, so that ddb can keep control (almost) no matter how it is
entered. This breaks time-critical interrupts while the system is
stopped in ddb, but I haven't noticed any significant problems except
that applications become confused about the time. Lost time will be
adjusted for later. Anyway, the half-baked disabling of interrupts in
Debugger() gives the same problems for the usual way of entering ddb.


# 81544 12-Aug-2001 iwasaki

Fix some trivial bugs.
- fix segment limit mis-calculation for GCODE_SEL, GDATA_SEL, GPRIV_SEL,
LUCODE_SEL and LUDATA_SEL.
- move `loader(8) metadata' related printf() after cninit().
- use atop macro (address to pages) for segment limit calculation
instead of i386_btop macro (bytes to pages).
- fix style bugs for the declarations of ints.

Reviewed by: bde, msmith (and arch & audit ML)


# 81265 08-Aug-2001 peter

Zap 'ptrace(PT_READ_U, ...)' and 'ptrace(PT_WRITE_U, ...)' since they
are a really nasty interface that should have been killed long ago
when 'ptrace(PT_[SG]ETREGS' etc came along. The entity that they
operate on (struct user) will not be around much longer since it
is part-per-process and part-per-thread in a post-KSE world.

gdb does not actually use this except for the obscure 'info udot'
command which does a hexdump of as much of the child's 'struct user'
as it can get. It carries its own #defines so it doesn't break
compiles.


# 80421 26-Jul-2001 peter

Call the early tunable setup functions as soon as kern_envp is available.
Some things depend on hz being set not long after this.


# 79893 19-Jul-2001 bsd

swtch.s: During context save, use the correct bit mask for clearing
the non-reserved bits of dr7.

During context restore, load dr7 in such a way as to not
disturb reserved bits.

machdep.c: Don't explicitly disallow the setting of the reserved bits
in dr7 since we now keep from setting them when we load dr7
from the PCB.

This allows one to write back the dr7 value obtained from
the system without triggering an EINVAL (one of the
reserved bits always seems to be set after taking a trace
trap).

MFC after: 7 days


# 79609 12-Jul-2001 peter

Activate SSE/SIMD. This is the extra context switching support that
we are required to do if we let user processes use the extra 128 bit
registers etc.

This is the base part of the diff I got from:
http://www.issei.org/issei/FreeBSD/sse.html
I believe this is by: Mr. SUZUKI Issei <issei@issei.org>
SMP support apparently by: Takekazu KATO <kato@chino.it.okayama-u.ac.jp>
Test code by: NAKAMURA Kazushi <kaz@kobe1995.net>, see
http://kobe1995.net/~kaz/FreeBSD/SSE.en.html

I have fixed a couple of style(9) deviations. I have some followup
commits to fix a couple of non-style things.


# 79573 11-Jul-2001 bsd

Add 'hwatch' and 'dhwatch' ddb commands analogous to 'watch' and
'dwatch'. The new commands install hardware watchpoints if supported
by the architecture and if there are enough registers to cover the
desired memory area.

No objection by: audit@, hackers@

MFC after: 2 weeks


# 79224 04-Jul-2001 dillon

With Alfred's permission, remove vm_mtx in favor of a fine-grained approach
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.


# 79153 03-Jul-2001 tmm

Make the code to read the kernel message buffer via sysctl machine-
independent and rename the corresponding sysctls from machdep.msgbuf and
machdep.msgbuf_clear (i386 only) to kern.msgbuf and kern.msgbuf_clear.


# 78981 29-Jun-2001 imp

Remove cruft from old bus.


# 78962 29-Jun-2001 jhb

Add a new MI pointer to the process' trapframe p_frame instead of using
various differently named pointers buried under p_md.

Reviewed by: jake (in principle)


# 78631 22-Jun-2001 peter

Make the hw.physmem and hw.usermem variables unsigned so that they dont
come up as negative on machines with >2GB ram.


# 78427 18-Jun-2001 jhb

Initialize mutexes needed early on all in the same place so that the
startup routine more closely matches that of alpha and ia64. At some
point the common mutexes shared across all platforms probably should move
into sys/kern_mutex.c.


# 78135 12-Jun-2001 peter

Hints overhaul:
- Replace some very poorly thought out API hacks that should have been
fixed a long while ago.
- Provide some much more flexible search functions (resource_find_*())
- Use strings for storage instead of an outgrowth of the rather
inconvenient temporary ioconf table from config(). We already had a
fallback to using strings before malloc/vm was running anyway.


# 77582 01-Jun-2001 tmm

Clean up the code exporting interrupt statistics via sysctl a bit:
- move the sysctl code to kern_intr.c
- do not use INTRCNT_COUNT, but rather eintrcnt - intrcnt to determine
the length of the intrcnt array
- move the declarations of intrnames, eintrnames, intrcnt and eintrcnt
from machine-dependent include files to sys/interrupt.h
- remove the hw.nintr sysctl, it is not needed.
- fix various style bugs

Requested by: bde
Reviewed by: bde (some time ago)


# 76827 19-May-2001 alfred

Introduce a global lock for the vm subsystem (vm_mtx).

vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems can now call the base page allocators safely.

Almost all atomic ops were removed as they are covered under the
vm mutex.

Alpha and ia64 now need to catch up to i386's trap handlers.

FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).

Reviewed (partially) by: jake, jhb


# 76770 17-May-2001 jhb

- Move the setting of bootverbose to a MI SI_SUB_TUNABLES SYSINIT.
- Attach a writable sysctl to bootverbose (debug.bootverbose) so it can be
toggled after boot.
- Move the printf of the version string to a SI_SUB_COPYRIGHT SYSINIT just
afer the display of the copyright message instead of doing it by hand in
three MD places.


# 76650 15-May-2001 jhb

Remove unneeded includes of sys/ipl.h and machine/ipl.h.


# 76525 12-May-2001 deischen

Revert part of last commit. Instead of using %fs for KSD/TSD, we'll
follow Linux' convention and use %gs. This adds back the setting of
%fs to a sane value in sendsig(). The value of %gs remains preserved
to whatever it was in user context.


# 76440 10-May-2001 jhb

- Split out the support for per-CPU data from the SMP code. UP kernels
have per-CPU data and gdb on the i386 at least needs access to it.
- Clean up includes in kern_idle.c and subr_smp.c.

Reviewed by: jake


# 76298 06-May-2001 deischen

When setting up the frame to invoke a signal handler, preserve the
%fs and %gs registers instead of setting them to known sane values.
%fs is going to be used for thread/KSE specific data by the new
threads library; we'll want it to be valid inside of signal handlers.

According to bde, Linux preserves the state of %fs and %gs when setting
up signal handlers, so there is precedent for doing this.

The same changes should be made in the Linux emulator, but when made,
they seem to break (at least one version of) the IBM JDK for Linux
(reported by drew).

Approved by: bde


# 76078 27-Apr-2001 jhb

Overhaul of the SMP code. Several portions of the SMP kernel support have
been made machine independent and various other adjustments have been made
to support Alpha SMP.

- It splits the per-process portions of hardclock() and statclock() off
into hardclock_process() and statclock_process() respectively. hardclock()
and statclock() call the *_process() functions for the current process so
that UP systems will run as before. For SMP systems, it is simply necessary
to ensure that all other processors execute the *_process() functions when the
main clock functions are triggered on one CPU by an interrupt. For the alpha
4100, clock interrupts are delievered in a staggered broadcast fashion, so
we simply call hardclock/statclock on the boot CPU and call the *_process()
functions on the secondaries. For x86, we call statclock and hardclock as
usual and then call forward_hardclock/statclock in the MD code to send an IPI
to cause the AP's to execute forwared_hardclock/statclock which then call the
*_process() functions.
- forward_signal() and forward_roundrobin() have been reworked to be MI and to
involve less hackery. Now the cpu doing the forward sets any flags, etc. and
sends a very simple IPI_AST to the other cpu(s). AST IPIs now just basically
return so that they can execute ast() and don't bother with setting the
astpending or needresched flags themselves. This also removes the loop in
forward_signal() as sched_lock closes the race condition that the loop worked
around.
- need_resched(), resched_wanted() and clear_resched() have been changed to take
a process to act on rather than assuming curproc so that they can be used to
implement forward_roundrobin() as described above.
- Various other SMP variables have been moved to a MI subr_smp.c and a new
header sys/smp.h declares MI SMP variables and API's. The IPI API's from
machine/ipl.h have moved to machine/smp.h which is included by sys/smp.h.
- The globaldata_register() and globaldata_find() functions as well as the
SLIST of globaldata structures has become MI and moved into subr_smp.c.
Also, the globaldata list is only available if SMP support is compiled in.

Reviewed by: jake, peter
Looked over by: eivind


# 74912 28-Mar-2001 jhb

Rework the witness code to work with sx locks as well as mutexes.
- Introduce lock classes and lock objects. Each lock class specifies a
name and set of flags (or properties) shared by all locks of a given
type. Currently there are three lock classes: spin mutexes, sleep
mutexes, and sx locks. A lock object specifies properties of an
additional lock along with a lock name and all of the extra stuff needed
to make witness work with a given lock. This abstract lock stuff is
defined in sys/lock.h. The lockmgr constants, types, and prototypes have
been moved to sys/lockmgr.h. For temporary backwards compatability,
sys/lock.h includes sys/lockmgr.h.
- Replace proc->p_spinlocks with a per-CPU list, PCPU(spinlocks), of spin
locks held. By making this per-cpu, we do not have to jump through
magic hoops to deal with sched_lock changing ownership during context
switches.
- Replace proc->p_heldmtx, formerly a list of held sleep mutexes, with
proc->p_sleeplocks, which is a list of held sleep locks including sleep
mutexes and sx locks.
- Add helper macros for logging lock events via the KTR_LOCK KTR logging
level so that the log messages are consistent.
- Add some new flags that can be passed to mtx_init():
- MTX_NOWITNESS - specifies that this lock should be ignored by witness.
This is used for the mutex that blocks a sx lock for example.
- MTX_QUIET - this is not new, but you can pass this to mtx_init() now
and no events will be logged for this lock, so that one doesn't have
to change all the individual mtx_lock/unlock() operations.
- All lock objects maintain an initialized flag. Use this flag to export
a mtx_initialized() macro that can be safely called from drivers. Also,
we on longer walk the all_mtx list if MUTEX_DEBUG is defined as witness
performs the corresponding checks using the initialized flag.
- The lock order reversal messages have been improved to output slightly
more accurate file and line numbers.


# 74670 23-Mar-2001 tmm

Export intrnames and intrcnt as sysctls (hw.nintr, hw.intrnames and
hw.intrcnt).

Approved by: rwatson


# 73929 07-Mar-2001 jhb

Grab the process lock while calling psignal and before calling psignal.


# 73001 25-Feb-2001 jake

- Rename the lcall system call handler from Xsyscall to Xlcall_syscall
to be more like Xint0x80_syscall and less like c function syscall().
- Reduce code duplication between the int0x80 and lcall handlers by
shuffling the elfags into the right place, saving the sizeof the
instruction in tf_err and jumping into the common int0x80 code.

Reviewed by: peter


# 72930 23-Feb-2001 peter

Activate USER_LDT by default. The new thread libraries are going to
depend on this. The linux ABI emulator tries to use it for some linux
binaries too. VM86 had a bigger cost than this and it was made default
a while ago.

Reviewed by: jhb, imp


# 72746 20-Feb-2001 jhb

- Don't call clear_resched() in userret(), instead, clear the resched flag
in mi_switch() just before calling cpu_switch() so that the first switch
after a resched request will satisfy the request.
- While I'm at it, move a few things into mi_switch() and out of
cpu_switch(), specifically set the p_oncpu and p_lastcpu members of
proc in mi_switch(), and handle the sched_lock state change across a
context switch in mi_switch().
- Since cpu_switch() no longer handles the sched_lock state change, we
have to setup an initial state for sched_lock in fork_exit() before we
release it.


# 72226 09-Feb-2001 jhb

Move the initailization of the proc lock for proc0 very early into the MD
startup code.


# 72200 09-Feb-2001 bmilekic

Change and clean the mutex lock interface.

mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

similarily, for releasing a lock, we now have:

mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.

The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.

Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:

MTX_QUIET and MTX_NOSWITCH

The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:

mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.

Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.

Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.

Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.

Finally, caught up to the interface changes in all sys code.

Contributors: jake, jhb, jasone (in no particular order)


# 71983 04-Feb-2001 dillon

This commit represents work mainly submitted by Tor and slightly modified
by myself. It solves a serious vm_map corruption problem that can occur
with the buffer cache when block sizes > 64K are used. This code has been
heavily tested in -stable but only tested somewhat on -current. An MFC
will occur in a few days. My additions include the vm_map_simplify_entry()
and minor buffer cache boundry case fix.

Make the buffer cache use a system map for buffer cache KVM rather then a
normal map.

Ensure that VM objects are not allocated for system maps. There were cases
where a buffer map could wind up with a backing VM object -- normally
harmless, but this could also result in the buffer cache blocking in places
where it assumes no blocking will occur, possibly resulting in corrupted
maps.

Fix a minor boundry case in the buffer cache size limit is reached that
could result in non-optimal code.

Add vm_map_simplify_entry() calls to prevent 'creeping proliferation'
of vm_map_entry's in the buffer cache's vm_map. Previously only a simple
linear optimization was made. (The buffer vm_map typically has only a
handful of vm_map_entry's. This stabilizes it at that level permanently).

PR: 20609
Submitted by: (Tor Egge) tegge


# 71785 29-Jan-2001 peter

Send "#if NISA > 0" to the bit-bucket and replace it with an option.
These were compile-time "is the isa code present?" tests and not
'how many isa busses' tests.


# 71647 25-Jan-2001 jhb

Whitespace fix: convert code indented 6 spaces to use tabs instead.


# 71576 24-Jan-2001 jasone

Convert all simplelocks to mutexes and remove the simplelock implementations.


# 71524 24-Jan-2001 jhb

- Proc locking.
- Setup proc0.p_heldmtx, proc0.contested, and curproc earlier so that we
can use mutexes.
- Initialize sched_lock and Giant earlier and enter Giant during init386.
- Use suser(9) instead of checking cr_uid directly.


# 71320 21-Jan-2001 jasone

Remove MUTEX_DECLARE() and MTX_COLD. Instead, postpone full mutex
initialization until after malloc() is safe to call, then iterate through
all mutexes and complete their initialization.

This change is necessary in order to avoid some circular bootstrapping
dependencies.


# 71261 19-Jan-2001 peter

Zap unused #include "apm.h"


# 71257 19-Jan-2001 peter

Use #ifdef DEV_NPX from opt_npx.h instead of #if NNPX > 0 from npx.h


# 71228 19-Jan-2001 bmilekic

Implement MTX_RECURSE flag for mtx_init().
All calls to mtx_init() for mutexes that recurse must now include
the MTX_RECURSE bit in the flag argument variable. This change is in
preparation for an upcoming (further) mutex API cleanup.
The witness code will call panic() if a lock is found to recurse but
the MTX_RECURSE bit was not set during the lock's initialization.

The old MTX_RECURSE "state" bit (in mtx_lock) has been renamed to
MTX_RECURSED, which is more appropriate given its meaning.

The following locks have been made "recursive," thus far:
eventhandler, Giant, callout, sched_lock, possibly some others declared
in the architecture-specific code, all of the network card driver locks
in pci/, as well as some other locks in dev/ stuff that I've found to
be recursive.

Reviewed by: jhb


# 71098 16-Jan-2001 peter

Stop doing runtime checking on i386 cpus for cpu class. The cpu is
slow enough as it is, without having to constantly check that it really
is an i386 still. It was possible to compile out the conditionals for
faster cpus by leaving out 'I386_CPU', but it was not possible to
unconditionally compile for the i386. You got the runtime checking whether
you wanted it or not. This makes I386_CPU mutually exclusive with the
other cpu types, and tidies things up a little in the process.

Reviewed by: alfred, markm, phk, benno, jlemon, jhb, jake, grog, msmith,
jasone, dcs, des (and a bunch more people who encouraged it)


# 70950 12-Jan-2001 bmilekic

Remove useless include of sys/mbuf.h (no longer useful since the
mbuf subsystem init was moved to a better place).


# 70861 10-Jan-2001 jake

Use PCPU_GET, PCPU_PTR and PCPU_SET to access all per-cpu variables
other then curproc.


# 70714 06-Jan-2001 jake

Use %fs to access per-cpu variables in uni-processor kernels the same
as multi-processor kernels. The old way made it difficult for kernel
modules to be portable between uni-processor and multi-processor
kernels. It is no longer necessary to jump through hoops.

- always load %fs with the private segment on entry to the kernel
- change the type of the self referntial pointer from struct privatespace
to struct globaldata
- make the globaldata symbol have value 0 in all cases, so the symbols
in globals.s are always offsets, not aliases for fields in globaldata
- define the globaldata space used for uniprocessor kernels in C, rather
than assembler
- change the assmebly language accessors to use %fs, add a macro
PCPU_ADDR(member, reg), which loads the register reg with the address
of the per-cpu variable member


# 69972 13-Dec-2000 tanimura

- If swap metadata does not fit into the KVM, reduce the number of
struct swblock entries by dividing the number of the entries by 2
until the swap metadata fits.

- Reject swapon(2) upon failure of swap_zone allocation.

This is just a temporary fix. Better solutions include:
(suggested by: dillon)

o reserving swap in SWAP_META_PAGES chunks, and
o swapping the swblock structures themselves.

Reviewed by: alfred, dillon


# 69586 05-Dec-2000 jake

Remove the last of the MD netisr code. It is now all MI. Remove
spending, which was unused now that all software interrupts have
their own thread. Make the legacy schednetisr use an atomic op
for setting bits in the netisr mask.

Reviewed by: jhb


# 69379 30-Nov-2000 marcel

Don't use p->p_sigstk.ss_flags to keep state of whether the
process is on the alternate stack or not. For compatibility
with sigstack(2) state is being updated if such is needed.

We now determine whether the process is on the alternate
stack by looking at its stack pointer. This allows a process
to siglongjmp from a signal handler on the alternate stack
to the place of the sigsetjmp on the normal stack. When
maintaining state, this would have invalidated the state
information and causing a subsequent signal to be delivered
on the normal stack instead of the alternate stack.

PR: 22286


# 69147 25-Nov-2000 jlemon

Revert the last commit to the callout interface, and add a flag to
callout_init() indicating whether the callout is safe or not. Update
the callers of callout_init() to reflect the new interface.

Okayed by: Jake


# 68889 19-Nov-2000 jake

- Protect the callout wheel with a separate spin mutex, callout_lock.
- Use the mutex in hardclock to ensure no races between it and
softclock.
- Make softclock be INTR_MPSAFE and provide a flag,
CALLOUT_MPSAFE, which specifies that a callout handler does not
need giant. There is still no way to set this flag when
regstering a callout.

Reviewed by: -smp@, jlemon


# 67708 27-Oct-2000 phk

Convert all users of fldoff() to offsetof(). fldoff() is bad
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.

Define __offsetof() in <machine/ansi.h>

Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>

Remove myriad of local offsetof() definitions.

Remove includes of <stddef.h> in kernel code.

NB: Kernelcode should *never* include from /usr/include !

Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.

Deprecate <struct.h> with a warning. The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.

Paritials reviews by: various.
Significant brucifications by: bde


# 67694 27-Oct-2000 bde

Declare or #define per-cpu globals in <machine/globals.h> in all cases.
The i386 UP case was messily different.


# 67357 20-Oct-2000 jhb

- machine/mutex.h -> sys/mutex.h
- Use MUTEX_DECLARE() and MTX_COLD for Giant and sched_lock.


# 67308 19-Oct-2000 jhb

Axe the idle_event eventhandler, and add a MD cpu_idle function used
for things such as halting CPU's, idling CPU's, etc.

Discussed with: msmith


# 67265 17-Oct-2000 jhb

- Catch up to moving headers, machine/ipl.h -> sys/ipl.h
- Fix some whitespace bogons.

Submitted by: bde (2)


# 66716 06-Oct-2000 jhb

- Change fast interrupts on x86 to push a full interrupt frame and to
return through doreti to handle ast's. This is necessary for the
clock interrupts to work properly.
- Change the clock interrupts on the x86 to be fast instead of threaded.
This is needed because both hardclock() and statclock() need to run in
the context of the current process, not in a separate thread context.
- Kill the prevproc hack as it is no longer needed.
- We really need Giant when we call psignal(), but we don't want to block
during the clock interrupt. Instead, use two p_flag's in the proc struct
to mark the current process as having a pending SIGVTALRM or a SIGPROF
and let them be delivered during ast() when hardclock() has finished
running.
- Remove CLKF_BASEPRI, which was #ifdef'd out on the x86 anyways. It was
broken on the x86 if it was turned on since cpl is gone. It's only use
was to bogusly run softclock() directly during hardclock() rather than
scheduling an SWI.
- Remove the COM_LOCK simplelock and replace it with a clock_lock spin
mutex. Since the spin mutex already handles disabling/restoring
interrupts appropriately, this also lets us axe all the *_intr() fu.
- Back out the hacks in the APIC_IO x86 cpu_initclocks() code to use
temporary fast interrupts for the APIC trial.
- Add two new process flags P_ALRMPEND and P_PROFPEND to mark the pending
signals in hardclock() that are to be delivered in ast().

Submitted by: jakeb (making statclock safe in a fast interrupt)
Submitted by: cp (concept of delaying signals until ast())


# 66559 02-Oct-2000 peter

Fix a cosmetic sign problem on machines with 4G of ram.
0x00312000 - 0xe5fe7fff, 3855441920 bytes (4294859990 pages)
.. becomes
0x00314000 - 0xe5fe7fff, 3855433728 bytes (941268 pages)


# 66489 30-Sep-2000 msmith

More updates to the ACPI code:

- Move all register I/O into acpi_io.c
- Move event handling into acpi_event.c
- Reorganise headers into acpivar/acpireg/acpiio
- Move find-RSDT and find-ACPI-owned-memory into acpi_machdep
- Allocate all resources (except those detailed only by AML)
as real resources. Add infrastructure that will make adding
resource support to AML code easy.
- Remove all ACPI #ifdefs in non-ACPI code
- Removed unnecessary includes
- Minor style and commenting fixes

Reviewed by: iwasaki


# 66475 30-Sep-2000 bmilekic

Big mbuf subsystem diff #1: incorporate mutexes and fix things up somewhat
to accomodate the changes.

Here's a list of things that have changed (I may have left out a few); for a
relatively complete list, see http://people.freebsd.org/~bmilekic/mtx_journal

* Remove old (once useful) mcluster code for MCLBYTES > PAGE_SIZE which
nobody uses anymore. It was great while it lasted, but now we're moving
onto bigger and better things (Approved by: wollman).

* Practically re-wrote the allocation macros in sys/sys/mbuf.h to accomodate
new allocations which grab the necessary lock.

* Make sure that necessary mbstat variables are manipulated with
corresponding atomic() routines.

* Changed the "wait" routines, cleaned it up, made one routine that does
the job.

* Generalized MWAKEUP() macro. Got rid of m_retry and m_retryhdr, as they
are now included in the generalized "wait" routines.

* Sleep routines now use msleep().

* Free lists have locks.

* etc... probably other stuff I'm missing...

Things to look out for and work on later:

* find a better way to (dynamically) adjust EXT_COUNTERS

* move necessity to recurse on a lock from drain routines by providing
lock-free lower-level version of MFREE() (and possibly m_free()?).

* checkout include of mutex.h in sys/sys/mbuf.h - probably violating
general philosophy here.

The code has been reviewed quite a bit, but problems may arise... please,
don't panic! Send me Emails: bmilekic@freebsd.org

Reviewed by: jlemon, cp, alfred, others?


# 66277 22-Sep-2000 ps

Remove the NCPU, NAPIC, NBUS, NINTR config options. Make NAPIC,
NBUS, NINTR dynamic and set NCPU to a maximum of 16 under SMP.

Reviewed by: peter


# 66206 22-Sep-2000 msmith

Implement halt-on-idle in the !SMP case, which should significantly
reduce power consumption on most systems.


# 65856 14-Sep-2000 jhb

Remove the mtx_t, witness_t, and witness_blessed_t types. Instead, just
use struct mtx, struct witness, and struct witness_blessed.

Requested by: bde


# 65811 13-Sep-2000 bde

Fixed hang on booting with -d. mtx_enter() was called on an uninitialized
lock. The quick fix in trap.c was not quite the version tested and had no
effect; back it out.


# 65587 07-Sep-2000 jake

Don't use currentldt as an L-value.
This should fix options USER_LDT.

Reported-by: John Hay <jhay@zibbi.mikom.csir.co.za>
Nickolay Dudorov <nnd@mail.nsk.ru>


# 65557 07-Sep-2000 jasone

Major update to the way synchronization is done in the kernel. Highlights
include:

* Mutual exclusion is used instead of spl*(). See mutex(9). (Note: The
alpha port is still in transition and currently uses both.)

* Per-CPU idle processes.

* Interrupts are run in their own separate kernel threads and can be
preempted (i386 only).

Partially contributed by: BSDi (BSD/OS)
Submissions by (at least): cp, dfr, dillon, grog, jake, jhb, sheldonh


# 65389 03-Sep-2000 peter

Complain if we cannot find loader(8) metadata.


# 65292 31-Aug-2000 takawata

Merge rest piece of ACPI driver.To activate acpi driver ,add

device acpi

line. Merge finished. But still experimental phase.Need more hack!

Obtained from:ACPI for FreeBSD project


# 64837 19-Aug-2000 dwmalone

Replace the mbuf external reference counting code with something
that should be better.

The old code counted references to mbuf clusters by using the offset
of the cluster from the start of memory allocated for mbufs and
clusters as an index into an array of chars, which did the reference
counting. If the external storage was not a cluster then reference
counting had to be done by the code using that external storage.

NetBSD's system of linked lists of mbufs was cosidered, but Alfred
felt it would have locking issues when the kernel was made more
SMP friendly.

The system implimented uses a pool of unions to track external
storage. The union contains an int for counting the references and
a pointer for forming a free list. The reference counts are
incremented and decremented atomically and so should be SMP friendly.
This system can track reference counts for any sort of external
storage.

Access to the reference counting stuff is now through macros defined
in mbuf.h, so it should be easier to make changes to the system in
the future.

The possibility of storing the reference count in one of the
referencing mbufs was considered, but was rejected 'cos it would
often leave extra mbufs allocated. Storing the reference count in
the cluster was also considered, but because the external storage
may not be a cluster this isn't an option.

The size of the pool of reference counters is available in the
stats provided by "netstat -m".

PR: 19866
Submitted by: Bosko Milekic <bmilekic@dsuper.net>
Reviewed by: alfred (glanced at by others on -net)


# 64781 17-Aug-2000 bsd

Don't let an illegal value for dr7 get set, which can lead to an
unexpected TRCTRAP.

Reported by: John W. De Boskey <jwd@FreeBSD.org>


# 64592 13-Aug-2000 jhb

Include machine/cputypes.h so we get the cpu_class variable. This is needed
if I386_CPU is defined in the kernel config file.


# 64529 11-Aug-2000 peter

Clean up some low level bootstrap code:

- stop using the evil 'struct trapframe' argument for mi_startup()
(formerly main()). There are much better ways of doing it.
- do not use prepare_usermode() - setregs() in execve() will do it
all for us as long as the p_md.md_regs pointer is set. (which is
now done in machdep.c rather than init_main.c. The Alpha port did it
this way all along and is much cleaner).
- collect all the magic %cr0 etc register settings into one place and
have the AP's call that instead of using magic numbers (!!) that keep
changing over and over again.
- Make it safe to call kthread_create() earlier, including during the
device probe sequence. It doesn't need the callback mechanism that
NetBSD's version uses.
- kthreads created this way are root-less as they exist before the root
filesystem is mounted. init(1) is set up so that it aquires the root
pointers prior to running. If other kthreads want filesystem acccess
we can make this code more generic.
- set all threads start times once we have decided what time it is.
- init uses a trampoline rather than the evil prepare_usermode() hack.
- kern_descrip.c has a couple of tweaks to deal with forking when there
is no rootdir or cwd etc.
- adjust the early SYSINIT() sequence so that a few prereqisites are in
place. eg: make sure the run queue is initialized before doing forks.

With this, the USB code can easily create a kthread to do the device
tree discovery. (I have tested it, it works nicely).

There are still some open issues before this is truely useful.
- tsleep() does not like working before the clock is running. It
sort-of tries to spin wait, but it can do more useful things now.
- stopping a kthread in kld code at unload time is "interesting" but
we have a solution for that.

The Alpha code needs no changes for this. It already uses pretty much the
same strategies, but a little cleaner.


# 62870 10-Jul-2000 kris

Don't call printf with no format string.

Reviewed by: msmith


# 62573 04-Jul-2000 phk

Previous commit changing SYSCTL_HANDLER_ARGS violated KNF.

Pointed out by: bde


# 62454 03-Jul-2000 phk

Style police catches up with rev 1.26 of src/sys/sys/sysctl.h:

Sanitize SYSCTL_HANDLER_ARGS so that simplistic tools can grog our
sources:

-sysctl_vm_zone SYSCTL_HANDLER_ARGS
+sysctl_vm_zone (SYSCTL_HANDLER_ARGS)


# 62057 25-Jun-2000 markm

Strip out the machine-independant parts of the memory device.
/dev/(u)random, /dev/null, /dev/zero are all moving to machine-independant
drivers.
Reviewed by: dfr


# 61474 10-Jun-2000 peter

Unused include: #include "ether.h"


# 61220 03-Jun-2000 bde

Fixed some style bugs in the signal handling funcations. This doesn't
change the object file.


# 60041 05-May-2000 phk

Separate the struct bio related stuff out of <sys/buf.h> into
<sys/bio.h>.

<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.

Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.

Still a few bogus uses of struct buf to track down.

Repocopy by: peter


# 59839 01-May-2000 peter

Move the MSG* and SEM* options to opt_sysvipc.h
Remove evil allocation macros from machdep.c (why was that there???) and
use malloc() instead.
Move paramters out of param.h and into the code itself.
Move a bunch of internal definitions from public sys/*.h headers (without
#ifdef _KERNEL even) into the code itself.

I had hoped to make some of this more dynamic, but the cost of doing
wakeups on all sleeping processes on old arrays was too frightening.
The other possibility is to initialize on the first use, and allow
dynamic sysctl changes to parameters right until that point. That would
allow /etc/rc.sysctl to change SEM* and MSG* defaults as we presently
do with SHM*, but without the nightmare of changing a running system.


# 59604 24-Apr-2000 obrien

* Use sys/sys/random.h rather than a i386 specific one.
* There was nothing that should be machine dependant about
i386/isa/random_machdep.c, so it is now sys/kern/kern_random.c.


# 59249 15-Apr-2000 phk

Complete the bio/buf divorce for all code below devfs::strategy

Exceptions:
Vinum untouched. This means that it cannot be compiled.
Greg Lehey is on the case.

CCD not converted yet, casts to struct buf (still safe)

atapi-cd casts to struct buf to examine B_PHYS


# 58934 02-Apr-2000 phk

Move B_ERROR flag to b_ioflags and call it BIO_ERROR.

(Much of this done by script)

Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.

Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.

Add bio_queue field for struct bio aware disksort.

Address a lot of stylistic issues brought up by bde.


# 58820 30-Mar-2000 peter

Make sysv-style shared memory tuneable params fully runtime adjustable
via sysctl. It's done pretty simply but it should be quite adequate.
Also move SHMMAXPGS from $machine/include/vmparam.h as the comments that
went with it were wrong... we don't allocate KVM space for the pages so
that comment is bogus.. The only practical limit is how much physical
ram you want to lock up as this stuff isn't paged out or swap backed.


# 58706 27-Mar-2000 dillon

Commit the buffer cache cleanup patch to 4.x and 5.x. This patch fixes a
fragmentation problem due to geteblk() reserving too much space for the
buffer and imposes a larger granularity (16K) on KVA reservations for
the buffer cache to avoid fragmentation issues. The buffer cache size
calculations have been redone to simplify them (fewer defines, better
comments, less chance of running out of KVA).

The geteblk() fix solves a performance problem that DG was able reproduce.

This patch does not completely fix the KVA fragmentation problems, but
it goes a long way

Mostly Reviewed by: bde and others
Approved by: jkh


# 58345 20-Mar-2000 phk

Remove B_READ, B_WRITE and B_FREEBUF and replace them with a new
field in struct buf: b_iocmd. The b_iocmd is enforced to have
exactly one bit set.

B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.

Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.

Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue. It is likely to write on your disk
where it should have been reading.

This change is a step in the direction towards a stackable BIO capability.

A lot of this patch were machine generated (Thanks to style(9) compliance!)

Vinum users: Greg has not had time to test this yet, be careful.


# 57571 28-Feb-2000 bsd

Reset the hardware debug registers when exec'ing a new image.

Reviewed by: bde,jlemon
Approved by: jkh


# 57362 20-Feb-2000 bsd

Don't forget to reset the hardware debug registers when a process that
was using them exits.

Don't allow a user process to cause the kernel to take a TRCTRAP on a
user space address.

Reviewed by: jlemon, sef
Approved by: jkh


# 57178 13-Feb-2000 peter

Clean up some loose ends in the network code, including the X.25 and ISO
#ifdefs. Clean out unused netisr's and leftover netisr linker set gunk.
Tested on x86 and alpha, including world.

Approved by: jkh


# 54188 06-Dec-1999 luoqi

User ldt sharing.


# 54121 04-Dec-1999 marcel

oszsigcode -> szosigcode

Pointed out by: bde


# 54120 04-Dec-1999 marcel

Fix type of sf_addr.

Pointed out by: bde


# 53648 24-Nov-1999 archie

Change the prototype of the strto* routines to make the second
parameter a char ** instead of a const char **. This make these
kernel routines consistent with the corresponding libc userland
routines.

Which is actually 'correct' is debatable, but consistency and
following the spec was deemed more important in this case.

Reviewed by (in concept): phk, bde


# 53624 23-Nov-1999 green

Fix a confusion between osigcontext and ucontext_t in the previous commit.
Since an osigcontext is smaller, if you check for a valid (much larger sized)
ucontext_t and it fails, we bogusly would reject the osigcontext as per
rev 1.378. Instead, check for osigcontext range validity first, and
ucontext_t later. This unbreaks Netscape.

Pointed to the right commit by: peter


# 53504 21-Nov-1999 pho

Moved useracc() to top of sigreturn as to avoid panic
caused by invalid arguments to rutine.

Reviewed by: marcel, phk


# 53503 21-Nov-1999 phk

s/p_cred->pc_ucred/p_ucred/g


# 53106 12-Nov-1999 marcel

Change the type of sf_addr in struct {o}sigframe from char* to
register_t.

Fix some style bugs and bitrotted comments.

Submitted by: bde


# 52720 31-Oct-1999 alc

The useracc() calls in osigreturn() and sigreturn() should specify
VM_PROT_READ rather than VM_PROT_WRITE. (This mistake predates
the B_READ/B_WRITE -> VM_PROT_READ/VM_PROT_WRITE change.)

Submitted by: bde


# 52644 30-Oct-1999 phk

Change useracc() and kernacc() to use VM_PROT_{READ|WRITE|EXECUTE} for the
"rw" argument, rather than hijacking B_{READ|WRITE}.

Fix two bugs (physio & cam) resulting by the confusion caused by this.

Submitted by: Tor.Egge@fast.no
Reviewed by: alc, ken (partly)


# 52635 29-Oct-1999 phk

useracc() the prequel:

Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>. This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.

This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.


# 52452 24-Oct-1999 dillon

Adjust the buffer cache to better handle small-memory machines. A
slightly older version of this code was tested by BDE and I.

Also fixes a lockup situation when kva gets too fragmented.

Remove the maxvmiobufspace variable and sysctl, they are no longer
used. Also cleanup (remove) #if 0 sections from prior commits.

This code is more of a hack, but presumably the whole buffer cache
implementation is going to be rewritten in the next year so it's no
big deal.


# 52199 13-Oct-1999 marcel

Fix a security bug. eflags was copied verbatim from userland.

Submitted by: bde


# 52150 12-Oct-1999 marcel

Now that userland, including modules don't use the osig* syscalls
and the kernel itself doesn't use any SYS_osig* constants, change
the syscalls to be of type COMPAT.


# 52140 11-Oct-1999 luoqi

Add a per-signal flag to mark handlers registered with osigaction, so we
can provide the correct context to each signal handler.

Fix broken sigsuspend(): don't use p_oldsigmask as a flag, use SAS_OLDMASK
as we did before the linuxthreads support merge (submitted by bde).

Move ps_sigstk from to p_sigacts to the main proc structure since signal
stack should not be shared among threads.

Move SAS_OLDMASK and SAS_ALTSTACK flags from sigacts::ps_flags to proc::p_flag.
Move PS_NOCLDSTOP and PS_NOCLDWAIT flags from proc::p_flag to procsig::ps_flag.

Reviewed by: marcel, jdp, bde


# 51984 07-Oct-1999 marcel

Simplification of the signal trampoline and other cleanups.

o Remove unused defines from genassym.c that were needed
by the trampoline.
o Add load_gs_param function to support.s that catches
a fault when %gs is loaded with an invalid descriptor.
The function returns EFAULT in that case.
o Remove struct trapframe from mcontext_t and replace it
with the list of registers.
o Modify sendsig and sigreturn accordingly.

This commit contains a patch by bde.

Reviewed by: luoqi, jdp


# 51942 04-Oct-1999 marcel

Re-introduction of sigcontext.

struct sigcontext and ucontext_t/mcontext_t are defined in such
a way that both (ie struct sigcontext and ucontext_t) can be
passed on to sigreturn. The signal handler is still given a
ucontext_t for maximum flexibility.

For backward compatibility sigreturn restores the state for the
alternate signal stack from sigcontext.sc_onstack and not from
ucontext_t.uc_stack. A good way to determine which value the
application has set and thus which value to use, is still open
for discussion.

NOTE: This change should only affect those binaries that use
sigcontext and/or ucontext_t. In the source tree itself
this is only doscmd. Recompilation is required for those
applications.

This commit also fixes a lot of style bugs without hopefully
adding new ones.

NOTE: struct sigaltstack.ss_size now has type size_t again. For
some reason I changed that into unsigned int.

Parts submitted by: bde
sigaltstack bug found by: bde


# 51908 03-Oct-1999 marcel

Reinstate the 4th argument to old signal handlers. Don't set it
when the handler uses siginfo_t.


# 51834 01-Oct-1999 marcel

Implement the use of si_addr in siginfo_t.

Suggested by: jdp


# 51833 01-Oct-1999 marcel

Don't check %cs *after* it has being set in sigreturn. If the check
fails, applications could end up running in kernel mode (oops).

Submitted by: bde


# 51792 29-Sep-1999 marcel

sigset_t change (part 3 of 5)
-----------------------------

By introducing a new sigframe so that the signal handler operates
on the new siginfo_t and on ucontext_t instead of sigcontext, we
now need two version of sendsig and sigreturn.

A flag in struct proc determines whether the process expects an
old sigframe or a new sigframe. The signal trampoline handles
which sigreturn to call. It does this by testing for a magic
cookie in the frame.

The alpha uses osigreturn to implement longjmp. This means that
osigreturn is not only used for compatibility with existing
binaries. To handle the new sigset_t, setjmp saves it in
sc_reserved (see NOTE).

the struct sigframe has been moved from frame.h to sigframe.h
to handle the complex header dependencies that was caused by
the new sigframe.

NOTE: For the i386, the size of jmp_buf has been increased to hold
the new sigset_t. On the alpha this has been prevented by
using sc_reserved in sigcontext.


# 51065 07-Sep-1999 luoqi

Save %gs in sigcontext when delivering a signal and restore them upon
return (in signal trampoline code). I plan to do the same on -stable,
so that we have a consistent interface to userland applications.

Reviewed by: bde


# 50477 28-Aug-1999 peter

$Id$ -> $FreeBSD$


# 49952 17-Aug-1999 msmith

Mindbogglingly, many BIOS vendors expect to be able to load %ds with
0x40 and then access data stored in real-mode segment 0x40, even when
called in protected mode. Microsoft unfortunately coddle these individuals,
and so must we if we want to run their code.

This change works around GPFs in some APM and PnP BIOS implementations.

Obtained from: Linux


# 49558 09-Aug-1999 phk

Merge the cons.c and cons.h to the best of my ability. alpha may or
may not compile, I can't test it.


# 49197 29-Jul-1999 msmith

Major update to the kernel's BIOS-calling ability.

- Add support for calling 32-bit code in other segments
- Add support for calling 16-bit protected mode code

Update APM to use this facility.

Submitted by: jlemon


# 48918 19-Jul-1999 peter

Fix a page size vs. KB mixup. The extra buffers allocated at a reduced
rate is meant to kick in at 64MB, not 256MB.

Reviewed by: Matthew Dillon <dillon@backplane.com>


# 48691 09-Jul-1999 jlemon

Implement support for hardware debug registers on the i386.

Submitted by: Brian Dean <brdean@unx.sas.com>


# 48677 08-Jul-1999 mckusick

These changes appear to give us benefits with both small (32MB) and
large (1G) memory machine configurations. I was able to run 'dbench 32'
on a 32MB system without bring the machine to a grinding halt.

* buffer cache hash table now dynamically allocated. This will
have no effect on memory consumption for smaller systems and
will help scale the buffer cache for larger systems.

* minor enhancement to pmap_clearbit(). I noticed that
all the calls to it used constant arguments. Making
it an inline allows the constants to propogate to
deeper inlines and should produce better code.

* removal of inherent vfs_ioopt support through the emplacement
of appropriate #ifdef's, with John's permission. If we do not
find a use for it by the end of the year we will remove it entirely.

* removal of getnewbufloops* counters & sysctl's - no longer
necessary for debugging, getnewbuf() is now optimal.

* buffer hash table functions removed from sys/buf.h and localized
to vfs_bio.c

* VFS_BIO_NEED_DIRTYFLUSH flag and support code added
( bwillwrite() ), allowing processes to block when too many dirty
buffers are present in the system.

* removal of a softdep test in bdwrite() that is no longer necessary
now that bdwrite() no longer attempts to flush dirty buffers.

* slight optimization added to bqrelse() - there is no reason
to test for available buffer space on B_DELWRI buffers.

* addition of reverse-scanning code to vfs_bio_awrite().
vfs_bio_awrite() will attempt to locate clusterable areas
in both the forward and reverse direction relative to the
offset of the buffer passed to it. This will probably not
make much of a difference now, but I believe we will start
to rely on it heavily in the future if we decide to shift
some of the burden of the clustering closer to the actual
I/O initiation.

* Removal of the newbufcnt and lastnewbuf counters that Kirk
added. They do not fix any race conditions that haven't already
been fixed by the gbincore() test done after the only call
to getnewbuf(). getnewbuf() is a static, so there is no chance
of it being misused by other modules. ( Unless Kirk can think
of a specific thing that this code fixes. I went through it
very carefully and didn't see anything ).

* removal of VOP_ISLOCKED() check in flushbufqueues(). I do not
think this check is necessary, the buffer should flush properly
whether the vnode is locked or not. ( yes? ).

* removal of extra arguments passed to getnewbuf() that are not
necessary.

* missed cluster_wbuild() that had to be a cluster_wbuild_wb() in
vfs_cluster.c

* vn_write() now calls bwillwrite() *PRIOR* to locking the vnode,
which should greatly aid flushing operations in heavy load
situations - both the pageout and update daemons will be able
to operate more efficiently.

* removal of b_usecount. We may add it back in later but for now
it is useless. Prior implementations of the buffer cache never
had enough buffers for it to be useful, and current implementations
which make more buffers available might not benefit relative to
the amount of sophistication required to implement a b_usecount.
Straight LRU should work just as well, especially when most things
are VMIO backed. I expect that (even though John will not like
this assumption) directories will become VMIO backed some point soon.

Submitted by: Matthew Dillon <dillon@backplane.com>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>


# 48621 06-Jul-1999 cracauer

Implement SA_SIGINFO for i386. Thanks to Bruce Evans for much more
than a review, this was a nice puzzle.

This is supposed to be binary and source compatible with older
applications that access the old FreeBSD-style three arguments to a
signal handler.

Except those applications that access hidden signal handler arguments
bejond the documented third one. If you have applications that do,
please let me know so that we take the opportunity to provide the
functionality they need in a documented manner.

Also except application that use 'struct sigframe' directly. You need
to recompile gdb and doscmd. `make world` is recommended.

Example program that demonstrates how SA_SIGINFO and old-style FreeBSD
handlers (with their three args) may be used in the same process is at
http://www3.cons.org/tmp/fbsd-siginfo.c

Programs that use the old FreeBSD-style three arguments are easy to
change to SA_SIGINFO (although they don't need to, since the old style
will still work):

Old args to signal handler:
void handler_sn(int sig, int code, struct sigcontext *scp)

New args:
void handler_si(int sig, siginfo_t *si, void *third)
where:
old:code == new:second->si_code
old:scp == &(new:si->si_scp) /* Passed by value! */

The latter is also pointed to by new:third, but accessing via
si->si_scp is preferred because it is type-save.

FreeBSD implementation notes:
- This is just the framework to make the interface POSIX compatible.
For now, no additional functionality is provided. This is supposed
to happen now, starting with floating point values.
- We don't use 'sigcontext_t.si_value' for now (POSIX meant it for
realtime-related values).
- Documentation will be updated when new functionality is added and
the exact arguments passed are determined. The comments in
sys/signal.h are meant to be useful.

Reviewed by: BDE


# 48579 05-Jul-1999 msmith

Move the initialisation/tuning of nmbclusters from param.c/machdep.c
into uipc_mbuf.c. This reduces three sets of identical tunable code to
one set, and puts the initialisation with the mbuf code proper.

Make NMBUFs tunable as well.

Move the nmbclusters sysctl here as well.

Move the initialisation of maxsockets from param.c to uipc_socket2.c,
next to its corresponding sysctl.

Use the new tunable macros for the kern.vm.kmem.size tunable (this should have
been in a separate commit, whoops).


# 48546 04-Jul-1999 jlemon

Some cleanup and rearrangement. hw.physmem is now an absolute quantity;
we will never use more memory than this value (if specified), but will always
check memory for validity up to this amount.

Get rid of the speculative_mprobe option; the memory amount can now be
specified by hw.physmem.


# 48544 04-Jul-1999 mckusick

The buffer queue mechanism has been reformulated. Instead of having
QUEUE_AGE, QUEUE_LRU, and QUEUE_EMPTY we instead have QUEUE_CLEAN,
QUEUE_DIRTY, QUEUE_EMPTY, and QUEUE_EMPTYKVA. With this patch clean
and dirty buffers have been separated. Empty buffers with KVM
assignments have been separated from truely empty buffers. getnewbuf()
has been rewritten and now operates in a 100% optimal fashion. That is,
it is able to find precisely the right kind of buffer it needs to
allocate a new buffer, defragment KVM, or to free-up an existing buffer
when the buffer cache is full (which is a steady-state situation for
the buffer cache).

Buffer flushing has been reorganized. Previously buffers were flushed
in the context of whatever process hit the conditions forcing buffer
flushing to occur. This resulted in processes blocking on conditions
unrelated to what they were doing. This also resulted in inappropriate
VFS stacking chains due to multiple processes getting stuck trying to
flush dirty buffers or due to a single process getting into a situation
where it might attempt to flush buffers recursively - a situation that
was only partially fixed in prior commits. We have added a new daemon
called the buf_daemon which is responsible for flushing dirty buffers
when the number of dirty buffers exceeds the vfs.hidirtybuffers limit.
This daemon attempts to dynamically adjust the rate at which dirty buffers
are flushed such that getnewbuf() calls (almost) never block.

The number of nbufs and amount of buffer space is now scaled past the
8MB limit that was previously imposed for systems with over 64MB of
memory, and the vfs.{lo,hi}dirtybuffers limits have been relaxed
somewhat. The number of physical buffers has been increased with the
intention that we will manage physical I/O differently in the future.

reassignbuf previously attempted to keep the dirtyblkhd list sorted which
could result in non-deterministic operation under certain conditions,
such as when a large number of dirty buffers are being managed. This
algorithm has been changed. reassignbuf now keeps buffers locally sorted
if it can do so cheaply, and otherwise gives up and adds buffers to
the head of the dirtyblkhd list. The new algorithm is deterministic but
not perfect. The new algorithm greatly reduces problems that previously
occured when write_behind was turned off in the system.

The P_FLSINPROG proc->p_flag bit has been replaced by the more descriptive
P_BUFEXHAUST bit. This bit allows processes working with filesystem
buffers to use available emergency reserves. Normal processes do not set
this bit and are not allowed to dig into emergency reserves. The purpose
of this bit is to avoid low-memory deadlocks.

A small race condition was fixed in getpbuf() in vm/vm_pager.c.

Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>


# 48476 02-Jul-1999 msmith

Lightly overhaul the memory sizing code again.

- The kernel environment variable 'hw.physmem' can be used to set the
amount of physical memory space, based at 0, that FreeBSD will use.
Any memory detected over this limit is ignored. Documentation for
this is available under 'help set tunables' in the loader.

- In the case where system memory size can't be accurately determined,
hw.physmem is used as a best-guess memory size, but speculative
probing will be used to determine actual memory size if any of the
guesses or hints are 16M or more.

- If RB_VERBOSE, we list the memory regions as we test them.

- The compile-time option MAXMEM supplies a default value for
'hw.physmem'.


# 48445 02-Jul-1999 peter

Zap totally the npx0 memory size override. It only worked if statically
specified in the kernel config file - but setting options MAXMEM works
exactly the same. Userconfig overrides of this have not worked for
ages.

Also, change the getenv for the loader override to hw.physmem based on a
prior suggestion from Mike Smith. I think he still wants to change this
some, but this shouldn't get in his way. This is a forced setting of
the memory size, not a "cap". We probably should have a plain 'maxmem'
variable as well which does do a cap, without loosing the bios memory
configuration data.


# 48405 01-Jul-1999 peter

Look up the kernel environment for MAXMEM as a final override for the
memory size. If somebody wants to change the name, fine - I used this
since it's consistant with the config variable it replaces.
This is intended to replace the npx0 msize hack (which no longer works).


# 48404 01-Jul-1999 peter

Move kern_envp and preload initialization a little earlier so that we
can do a getenv_int() inside the memory sizing routines to override the
memory limit.


# 48327 28-Jun-1999 luoqi

Save common_tssd before it's loaded and the busy bit set.

Submitted by: bde


# 48203 24-Jun-1999 jlemon

Fix warning message; that was 4GB, not 2GB. I apparently can't do
arithmetic today.


# 48202 24-Jun-1999 jlemon

Explicitly ignore any memory > 2GB, we don't support it yet.


# 48005 18-Jun-1999 bde

Changed the global `idt' from an array to a pointer so that npx.c
automatically hacks on the active copy of the IDT if f00f_hack()
has changed it. This also allows simplifications in setidt().
This fixes breakage of FP exception handling by rev.1.55 of
sys/kernel.h. FP exceptions were sent to npx.c's probe handlers
because npx.c "restored" the old handlers to the wrong copy of the
IDT. The SYSINIT for f00f_hack() was purposely run quite late to
avoid problems like this, but it is bogusly associated with the
SYSINIT for proc0 so it was moved with the latter.

Problem reported and fix tested by: Martin Cracauer <cracauer@cons.org>


# 47892 13-Jun-1999 alc

Use pmap_kenter instead of pmap_enter to map the message buffer.


# 47862 10-Jun-1999 jlemon

Change variable used for calculating ending address of physical memory
from 'int' to 'vm_offset_t'.

Spotted by: Richard Cownie <tich@ma.ikos.com>


# 47688 01-Jun-1999 jlemon

Unbreak memory sizing for SMP.


# 47679 01-Jun-1999 jlemon

Null commit; note that there is a new memory sizing routine that uses
the BIOS calls to determine the memory configuration. This should fix
problems with >64M for good.

Reviewed by: Mike Smith


# 47678 01-Jun-1999 jlemon

Unifdef VM86.

Reviewed by: silence on on -current


# 47642 31-May-1999 dfr

Remove fd driver from its old home and change files which include rtc.h
to account for its new location.


# 47081 12-May-1999 luoqi

Unbreak VESA on SMP.


# 46539 06-May-1999 luoqi

Initialize dblfault_tss.tss_fs to the per-cpu private data segment selector.


# 46537 06-May-1999 luoqi

Do not set curproc until proc0 is fully initialized (in proc0_init()).


# 46129 28-Apr-1999 luoqi

Enable vmspace sharing on SMP. Major changes are,
- %fs register is added to trapframe and saved/restored upon kernel entry/exit.
- Per-cpu pages are no longer mapped at the same virtual address.
- Each cpu now has a separate gdt selector table. A new segment selector
is added to point to per-cpu pages, per-cpu global variables are now
accessed through this new selector (%fs). The selectors in gdt table are
rearranged for cache line optimization.
- fask_vfork is now on as default for both UP and SMP.
- Some aio code cleanup.

Reviewed by: Alan Cox <alc@cs.rice.edu>
John Dyson <dyson@iquest.net>
Julian Elischer <julian@whistel.com>
Bruce Evans <bde@zeta.org.au>
David Greenman <dg@root.com>


# 46089 26-Apr-1999 peter

Register the netisr's via SYSINIT rather than linker sets.


# 45821 19-Apr-1999 peter

unifdef -DVM_STACK - it's been on for a while for x86 and was checked
and appeared to be working for the Alpha some time ago.


# 45720 16-Apr-1999 peter

Bring the 'new-bus' to the i386. This extensively changes the way the
i386 platform boots, it is no longer ISA-centric, and is fully dynamic.
Most old drivers compile and run without modification via 'compatability
shims' to enable a smoother transition. eisa, isapnp and pccard* are
not yet using the new resource manager. Once fully converted, all drivers
will be loadable, including PCI and ISA.

(Some other changes appear to have snuck in, including a port of Soren's
ATA driver to the Alpha. Soren, back this out if you need to.)

This is a checkpoint of work-in-progress, but is quite functional.

The bulk of the work was done over the last few years by Doug Rabson and
Garrett Wollman.

Approved by: core


# 45270 03-Apr-1999 jdp

Restore support for executing BSD/OS binaries on the i386 by passing
the address of the ps_strings structure to the process via %ebx.
For other kinds of binaries, %ebx is still zeroed as before.

Submitted by: Thomas Stephens <tas@stephens.org>
Reviewed by: jdp


# 44510 06-Mar-1999 wollman

Expose a slightly-lower-level interface to timeouts which allows callers
to manage their own memory. Tested on my machine (make buildworld).
I've made analogous changes on the alpha, but don't have a machine
to test.

Not-objected-to by: dg, gibbs


# 43970 13-Feb-1999 bde

Don't pass PSL_NT to vm86 signal handlers. Some vm86/real mode
programs, including msdos, set PSL_NT in probes for old cpu types,
although PSL_NT doesn't do anything useful in vm86 or real mode.
PSL_NT is even less useful in the signal handlers. It just causes
T_TSSFLT faults on return from syscalls made by the handlers.
These faults are fixed up lazily so that Xsyscall() doesn't have
to be slowed down to prevent them. The fault handler recently
started complaining about these faults occurring "with interrupts
disabled". It should not have, but the complaints pointed to this
bug.

PR: 9211


# 43887 11-Feb-1999 msmith

Zero p->retval[1] when starting a process. This value ends up in %edx
when the process starts, and having it nonzero causes statically-linked
Linux binaries to fail.

PR: i386/10015
Submitted by: Marcel Moolenaar <marcel@scc.nl>


# 43564 03-Feb-1999 dg

Fixed the type of target_page to vm_offset_t (unsigned). This fixes a
panic during boot on machines with >=2GB of RAM. Also changed some
incorrect printf conversion specifiers from %d to %u (signed to unsigned).
This fixes bugs when printing the amount of memory on machines with >=2GB
of RAM.


# 43340 28-Jan-1999 newton

Sun Bug ID 1251858 (on http://sunsolve1.sun.com) discusses the way that
Sun implemented iBCS2 compatibility on Solaris >= 2.6: The emulator
runs in user-mode, patching the LDT so that client programs making
syscalls through the old iBCS2 call gate get handled by the emulator
process. Unemulated syscalls therefore need their own call-gate that
bypasses the emulator. Sun chose LDT entry 4 to implement this, which
is what we've been using as LUDATA_SEL, so we need to change LUDATA_SEL
if we want to run Solaris executables.

Discussed with: Mike Smith


# 42705 15-Jan-1999 msmith

Fetch an overide for NMBCLUSTERS from the kernel environment. Never allow
the value to be reduced below that defined when the kernel was built.


# 42437 09-Jan-1999 bde

Fixed switching between consoles (sc0, vt0 or sioN) in userconfig.

Broken in: rev.1.315


# 42360 06-Jan-1999 julian

Add (but don't activate) code for a special VM option to make
downward growing stacks more general.
Add (but don't activate) code to use the new stack facility
when running threads, (specifically the linux threads support).
This allows people to use both linux compiled linuxthreads, and also the
native FreeBSD linux-threads port.

The code is conditional on VM_STACK. Not using this will
produce the old heavily tested system.

Submitted by: Richard Seaman <dick@tar.com>


# 41871 16-Dec-1998 bde

Removed the cast to a pointer in the definition of PS_STRINGS and
adjusted related casts to match (only in the kernel in this commit).
The pointer was only wanted in one place in kern_exec.c. Applications
should use the kern.ps_strings sysctl instead of PS_STRINGS, so they
shouldn't notice this change.


# 41629 10-Dec-1998 steve

Cleanup up the wording for the F00F bug workaround message.

PR: 8041
Submitted by: Dan Nelson <dnelson@emsphone.com>


# 41454 02-Dec-1998 kato

- For some old Cyrix CPUs, %cr2 is clobbered by interrupts. This
problem is worked around by using an interrupt gate for the page
fault handler. This code was originally made for NetBSD/pc98 by
Naofumi Honda <honda@kururu.math.sci.hokudai.ac.jp> and has already
been in PC98 tree. Because of this bug, trap_fatal cannot show
correct page fault address if %cr2 is obtained in this function.
Therefore, trap_fatal uses the value from trap() function.
- The trap handler always enables interruption when buggy application
or kernel code has disabled interrupts and then trapped. This code
was prepared by Bruce Evans <bde@FreeBSD.org>.

Submitted by: Bruce Evans <bde@FreeBSD.org>
Naofumi Honda <honda@kururu.math.sci.hokudai.ac.jp>


# 41362 26-Nov-1998 eivind

Staticize.


# 40866 03-Nov-1998 msmith

Remove the USERCONFIG_BOOT option. Userconfig script data is searched
for in a loaded module of type "userconfig_script". The RB_CONFIG
flag will always result in the user being left inside userconfig at
the end of the script's execution, regardless of 'quit' commands in
the script. If the RB_CONFIG flag is not specified, the user will
never be left inside userconfig, even if the script does not have an
explicit exit command.

Add the INTRO_USERCONFIG option. This option forces the userconfig 'intro'
screen (after a script has optionally been executed). There is no longer
a need to queue an 'intro' command.


# 40751 30-Oct-1998 msmith

Add the ability to specify where on the at_shutdown queue a handler is
installed.

Remove cpu_power_down, and replace it with an entry at the end of the
SHUTDOWN_FINAL queue in the only place it's used (APM).

Submitted by: Some ideas from Bruce Walter <walter@fortean.com>


# 40152 09-Oct-1998 peter

Relocate the preload module info from machdep specifically rather than
trying to do it in locore. We also walk through the module table
and relocate any MODINFO_ADDR pointers so that they become KVM relative
rather than physical addresses. This means that hacks for adding
0xf0000000 in places like MFS go away.


# 40089 09-Oct-1998 msmith

Initialise kernel environment and module metadata pointers.


# 39760 29-Sep-1998 abial

Add sysctl 'machdep.msgbuf_clear'. Setting it to anything causes the
kernel message buffer to be cleared. It comes handy in situations when
the only logging facility you have is the msgbuf.

Reviewed by: jkh


# 39648 25-Sep-1998 peter

Goodbye BOUNCE_BUFFERS, for a hack it has served us well.

The last consumer of this code (the old SCSI system) has left us and
the CAM code does it's own bouncing. The isa dma system has been
doing it's own bouncing for a while too.

Reviewed by: core


# 39197 14-Sep-1998 jdp

Add new functions fill_fpregs() and set_fpregs(), like fill_regs()
and set_regs() but for the floating point register state. The code
is stolen from procfs_machdep.c, and moved out of there into
machdep.c.

These functions are needed for generating ELF core dumps.


# 39176 14-Sep-1998 abial

This implements retrieving the contents of message buffer via sysctl(3)
as "machdep.msgbuf". It's needed in case of using stripped kernels, where
normal dmesg (which has to use kvm) doesn't work.

The buffer is unwound, meaning that the data will be linear, possibly
with some leading NULLs.

Reviewed by: Jordan K. Hubbard <jkh@freebsd.org>


# 38717 01-Sep-1998 kato

- Fix style bug.
- hw.ispc98 -> machdep.ispc98.

Submitted by: Garrett Wollman (hw -> machdep)


# 38700 31-Aug-1998 luoqi

Use 16bit register in inline asm code to set segment registers.


# 38673 31-Aug-1998 kato

- hw.machine_arch returns cpu architecture type.
- moved definition of MACHINE_ARCH from cpu.h to parm.h as alpha.
- Added definitions of _MACHINE and _MACHINE_ARCH.
- Added hw.ispc98. The hw.ispc98 is 1 in PC98 kernel and is 0 in
IBM-PC kernel.

Discussed with: John Birrell <jb@FreeBSD.ORG>


# 38422 18-Aug-1998 msmith

Presently there is only one `currentldt' variable for all cpus
in a SMP system. Unexpected things could happen if each cpu
has a different ldt setting and one cpu tries to use value
of currentldt set by another cpu.

The fix is to move currentldt to the per-cpu area. It includes
patches I filed in PR i386/6219 which are also user ldt related.

PR: i386/7591, i386/6219
Submitted by: Luoqi Chen <luoqi@watermarkgroup.com>


# 37555 11-Jul-1998 bde

Fixed printf format errors.


# 37315 30-Jun-1998 phk

Add 3 sysctl variables for future use by ps)1_


# 37099 21-Jun-1998 bde

Removed unused includes.
Ifdefed conditionally used includes.


# 37034 17-Jun-1998 bde

Don't declare isa device structs or isa interrupt handlers in <sys/conf>,
and don't depend on them being declared there. This will cause lots of
warnings for a few minutes until config is updated. Interrupt handlers
should never have been configured by config, and the machine generated
declarations get in the way of changing the arg type from int to void *.


# 36735 07-Jun-1998 dfr

This commit fixes various 64bit portability problems required for
FreeBSD/alpha. The most significant item is to change the command
argument to ioctl functions from int to u_long. This change brings us
inline with various other BSD versions. Driver writers may like to
use (__FreeBSD_version == 300003) to detect this change.

The prototype FreeBSD/alpha machdep will follow in a couple of days
time.


# 36605 03-Jun-1998 bde

Ifdefed the netisr support.

PR: 6760
Reviewed by: joerg


# 36441 28-May-1998 phk

Some cleanups related to timecounters and weird ifdefs in <sys/time.h>.

Clean up (or if antipodic: down) some of the msgbuf stuff.

Use an inline function rather than a macro for timecounter delta.

Maintain process "on-cpu" time as 64 bits of microseconds to avoid
needless second rollover overhead.

Avoid calling microuptime the second time in mi_switch() if we do
not pass through _idle in cpu_switch()

This should reduce our context-switch overhead a bit, in particular
on pre-P5 and SMP systems.

WARNING: Programs which muck about with struct proc in userland
will have to be fixed.

Reviewed, but found imperfect by: bde


# 36179 19-May-1998 phk

Make the size of the msgbuf (dmesg) a "normal" option.


# 36168 19-May-1998 tegge

Disallow reading the current kernel stack. Only the user structure and
the current registers should be accessible.
Reviewed by: David Greenman <dg@root.com>


# 35076 06-Apr-1998 peter

clean up #ifdefs, define the variables that have to be per-cpu on SMP
in globals.s only and use externs always.


# 34840 23-Mar-1998 jlemon

Add the ability to make real-mode BIOS calls from the kernel. Currently,
everything is contained inside #ifdef VM86, so this option must be
present in the config file to use this functionality.

Thanks to Tor Egge, these changes should work on SMP machines. However,
it may not be throughly SMP-safe.

Currently, the only BIOS calls made are memory-sizing routines at bootup,
these replace reading the RTC values.


# 34197 07-Mar-1998 tegge

The APs now reload the interrupt descriptor table pointer after
f00f_hack has run.

Use the global r_idt descriptor in f00f_hack when in SMP mode,
so the APs find the relocated interrupt descriptor table.

Submitted by: Partially from David A Adkins <adkin003@tc.umn.edu>


# 34057 05-Mar-1998 tegge

Use t_idt instead of idt inside setidt() if f00f_hack() has relocated the IDT.
Submitted by: Bruce Evans <bde@zeta.org.au>


# 33983 02-Mar-1998 peter

Update the ELF image activator to use some of the exec resources rather
than rolling it's own. This means that it now uses the "safe"
exec_map_first_page() to get the ld.so headers rather than risking a panic
on a page fault failure (eg: NFS server goes down).
Since all the ELF tools go to a lot of trouble to make sure everything
lives in the first page for executables, this is a win. I have not seen
any ELF executable on any system where all the headers didn't fit in the
first page with lots of room to spare.
I have been running variations of this code for some time on my pure ELF
systems.


# 33179 09-Feb-1998 eivind

Remove warnings from f00f_hack.


# 33134 06-Feb-1998 eivind

Back out DIAGNOSTIC changes.


# 33108 04-Feb-1998 eivind

Turn DIAGNOSTIC into a new-style option.


# 33051 03-Feb-1998 bde

Ifdefed some SMP and VM86 code. Note that although VM86 is not a global
option, the ifdef on it in a header works because only the name of the
VM86 extension is hidden.


# 32884 30-Jan-1998 dyson

Make the bounce buffer code a little more robust when space isn't
available. If there isn't bounce space available, the bounce code
is disabled. This will allow most large systems to run properly
when the bounce space is mistakenly allocated above 16MB.


# 32765 25-Jan-1998 kato

Even though BIOS writer's guide recommends cpuid instruction of Cyrix
6x86MX CPU is enabled (BIOS should not disable it), some BIOS disables
it via CCR4. In this case, cpu variable becomes CPU_486 and
identblue() is called. Because Cyrix 6x86MX has MSR and doesn't have
MSR1002, wrmsr instruction generates general protection fault.

Tested by: Simon Coggins <chaos@ultra.net.au>


# 32724 24-Jan-1998 dyson

Add better support for larger I/O clusters, including larger physical
I/O. The support is not mature yet, and some of the underlying implementation
needs help. However, support does exist for IDE devices now.


# 32702 22-Jan-1998 dyson

VM level code cleanups.

1) Start using TSM.
Struct procs continue to point to upages structure, after being freed.
Struct vmspace continues to point to pte object and kva space for kstack.
u_map is now superfluous.
2) vm_map's don't need to be reference counted. They always exist either
in the kernel or in a vmspace. The vmspaces are managed by reference
counts.
3) Remove the "wired" vm_map nonsense.
4) No need to keep a cache of kernel stack kva's.
5) Get rid of strange looking ++var, and change to var++.
6) Change more data structures to use our "zone" allocator. Added
struct proc, struct vmspace and struct vnode. This saves a significant
amount of kva space and physical memory. Additionally, this enables
TSM for the zone managed memory.
7) Keep ioopt disabled for now.
8) Remove the now bogus "single use" map concept.
9) Use generation counts or id's for data structures residing in TSM, where
it allows us to avoid unneeded restart overhead during traversals, where
blocking might occur.
10) Account better for memory deficits, so the pageout daemon will be able
to make enough memory available (experimental.)
11) Fix some vnode locking problems. (From Tor, I think.)
12) Add a check in ufs_lookup, to avoid lots of unneeded calls to bcmp.
(experimental.)
13) Significantly shrink, cleanup, and make slightly faster the vm_fault.c
code. Use generation counts, get rid of unneded collpase operations,
and clean up the cluster code.
14) Make vm_zone more suitable for TSM.

This commit is partially as a result of discussions and contributions from
other people, including DG, Tor Egge, PHK, and probably others that I
have forgotten to attribute (so let me know, if I forgot.)

This is not the infamous, final cleanup of the vnode stuff, but a necessary
step. Vnode mgmt should be correct, but things might still change, and
there is still some missing stuff (like ioopt, and physical backing of
non-merged cache files, debugging of layering concepts.)


# 32464 12-Jan-1998 dyson

Adjust upwards the size of exec map in order to take into account the
additional PAGE_SIZE needed for exec operatino.


# 32010 27-Dec-1997 peter

#include "opt_user_ldt.h" so that the #ifdef USER_LDT checks can work, as
commented about at length in the PR audit trail.

PR: 2412


# 31709 14-Dec-1997 dyson

After one of my analysis passes to evaluate methods for SMP TLB mgmt, I
noticed some major enhancements available for UP situations. The number
of UP TLB flushes is decreased much more than significantly with these
changes. Since a TLB flush appears to cost minimally approx 80 cycles,
this is a "nice" enhancement, equiv to eliminating between 40 and 160
instructions per TLB flush.

Changes include making sure that kernel threads all use the same PTD,
and eliminate unneeded PTD switches at context switch time.


# 31544 04-Dec-1997 jmg

document and make the NO_F00F_HACK a proper option...

also, sort some option includes while I'm here..

Forgotten by: sef


# 31535 04-Dec-1997 jkh

After consultation with David, change
#ifndef NO_F00F_HACK
to
#if defined(I586_CPU) && !defined(NO_F00F_HACK)


# 31515 03-Dec-1997 sef

Make has_f00f_bug extern, and get rid of some unused code in the f00f
code.

Submitted by: Mikael Karpberg & Cy Schubert


# 31507 03-Dec-1997 sef

Work around for the Intel Pentium F00F bug; this is Intel's recommended
workaround. Note that this currently eats up two pages extra in the system;
this could be alleviated by aligning idt correctly, and then only dealing with
that (as opposed to the current method of allocated two pages and copying the
IDT table to that, and then setting that to be the IDT table).


# 31397 24-Nov-1997 bde

Fixed multiple definitions of boothowto.


# 31337 21-Nov-1997 bde

Fixed setting of `safepri'. It should be SWI_AST_MASK most of the
time, but was left at 0. This caused the "can't happen" case in
splz_swi to happen for panics when tsleep() calls splx(safepri)
and there is a SWI_AST pending. This was harmless because the
the error handling happens to be right. Debugging this was tricky
because debugger traps force SWI_AST_MASK on in `cpl'.


# 31321 20-Nov-1997 bde

Moved some extern declarations to header files (unused ones to /dev/null).


# 31017 07-Nov-1997 phk

Rename some local variables to avoid shadowing other local variables.

Found by: -Wshadow


# 30994 06-Nov-1997 phk

Move the "retval" (3rd) parameter from all syscall functions and put
it in struct proc instead.

This fixes a boatload of compiler warning, and removes a lot of cruft
from the sources.

I have not removed the /*ARGSUSED*/, they will require some looking at.

libkvm, ps and other userland struct proc frobbing programs will need
recompiled.


# 30354 12-Oct-1997 phk

Last major round (Unless Bruce thinks of somthing :-) of malloc changes.

Distribute all but the most fundamental malloc types. This time I also
remembered the trick to making things static: Put "static" in front of
them.

A couple of finer points by: bde


# 30275 10-Oct-1997 peter

Compensate for pcb.h tweaks.

(Bruce pointed out the nesting)


# 30265 10-Oct-1997 peter

Convert the VM86 option from a global option to an option only depended
on by the files that use it. Changing the VM86 option now only causes
a recompile of a dozen files or so rather than the entire kernel.


# 29851 25-Sep-1997 dg

Fix a bug where the speculative memory probe wouldn't occur on systems that
report slightly more than 64MB of total memory. This can happen due to the
total being the sum of both base and extended memory.
Submitted by: Alan Cox <alc@cs.rice.edu>


# 29675 21-Sep-1997 gibbs

autoconf.c:
Add cpu_rootconf and cpu_dumpconf so that configuring these
two devices can be better controlled by the MI configuration
code.

machdep.c:
MD initialization code for the new callout interface.

trap.c:
Add support for printing out whether cam interrupts are masked
during a panic.


# 29663 21-Sep-1997 peter

Implement the parts needed for VM86 under SMP.


# 29110 04-Sep-1997 dg

Cosmetic change to last commit: speculative_mtest -> speculative_mprobe.


# 29109 04-Sep-1997 dg

Changed the memory sizing code so that if the following conditions
are met:

1) The BIOS indicates that there is exactly 64MB of RAM, and
2) The memory size isn't specified with the MAXMEM option or
the npx0 msize hack,

...then do a speculative memory probe beyond the 64MB's until the
first bad page is encountered. This is an admitted hack, but should
nonetheless deal with detecting the correct amount of memory in nearly
all of the modern systems with >64MB of RAM.
Also made a change that will cause the list of detected memory chunks
to be printed if bootverbose is set.


# 29041 02-Sep-1997 bde

Removed unused #includes.


# 28984 01-Sep-1997 bde

Move closer to supporting VM86 under SMP.

LINT now compiles but doesn't link. Other link-time breakage for LINT
is now visible (SMP is incompatible with SIMPLELOCK_DEBUG).
Submitted by: jlemon


# 28976 31-Aug-1997 bde

Fixed options SHOW_BUSYBUFS and PANIC_REBOOT_WAIT_TIME which were broken
by incomplete cutting and pasting from machdep.c to kern_shutdown.c.

PR: 3953


# 28808 26-Aug-1997 peter

Clean up the SMP AP bootstrap and eliminate the wretched idle procs.

- We now have enough per-cpu idle context, the real idle loop has been
revived (cpu's halt now with nothing to do).
- Some preliminary support for running some operations outside the
global lock (eg: zeroing "free but not yet zeroed pages") is present
but appears to cause problems. Off by default.
- the smp_active sysctl now behaves differently. It's merely a 'true/false'
option. Setting smp_active to zero causes the AP's to halt in the idle
loop and stop scheduling processes.
- bootstrap is a lot safer. Instead of sharing a statically compiled in
stack a number of times (which has caused lots of problems) and then
abandoning it, we use the idle context to boot the AP's directly. This
should help >2 cpu support since the bootlock stuff was in doubt.
- print physical apic id in traps.. helps identify private pages getting
out of sync. (You don't want to know how much hair I tore out with this!)

More cleanup to follow, this is more of a checkpoint than a
'finished' thing.


# 28496 21-Aug-1997 charnier

Revert my previous commit about using CS_SECURE macro.
Requested by: Bruce.


# 28359 18-Aug-1997 charnier

Use CS_SECURE macro.
Reviewed by: John Dyson


# 27993 09-Aug-1997 dyson

VM86 kernel support.
Work done by BSDI, Jonathan Lemon <jlemon@americantv.com>,
Mike Smith <msmith@gsoft.com.au>, Sean Eric Fagan <sef@kithrup.com>,
and probably alot of others.
Submitted by: Jnathan Lemon <jlemon@americantv.com>


# 27899 05-Aug-1997 dyson

Get rid of the ad-hoc memory allocator for vm_map_entries, in lieu of
a simple, clean zone type allocator. This new allocator will also be
used for machine dependent pmap PV entries.


# 27535 20-Jul-1997 bde

Removed unused #includes.


# 26994 27-Jun-1997 fsmp

Removed '#include <machine/smptests.h>' line, no longer needed.


# 26812 22-Jun-1997 peter

Preliminary support for per-cpu data pages.

This eliminates a lot of #ifdef SMP type code. Things like _curproc reside
in a data page that is unique on each cpu, eliminating the expensive macros
like: #define curproc (SMPcurproc[cpunumber()])

There are some unresolved bootstrap and address space sharing issues at
present, but Steve is waiting on this for other work. There is still some
strictly temporary code present that isn't exactly pretty.

This is part of a larger change that has run into some bumps, this part is
standalone so it should be safe. The temporary code goes away when the
full idle cpu support is finished.

Reviewed by: fsmp, dyson


# 26811 22-Jun-1997 peter

Kill some stale leftovers from the earlier attempts at SMP per-cpu pages


# 26659 15-Jun-1997 wollman

Fix another power down braino.


# 26657 15-Jun-1997 wollman

When APM is configured, turn off the power when halting for good.


# 26494 07-Jun-1997 bde

Preserve %fs and %gs across context switches. This has a relatively low
cost since it is only done in cpu_switch(), not for every exception.
The extra state is kept in the pcb, and handled much like the npx state,
with similar deficiencies (the state is not preserved across signal
handlers, and error handling loses state).


# 26373 02-Jun-1997 dfr

Move interrupt handling code from isa.c to a new file. This should make
isa.c (slightly) more portable and will make my life developing the really
portable version much easier.

Reviewed by: peter, fsmp


# 26171 26-May-1997 fsmp

Fix breakage from my last commit where mp_start() was missing from UP builds.


# 26155 26-May-1997 fsmp

Added a test called 'LATE_START'.

This is now the default, it delays most of the MP startup to the function
machdep.c:cpu_startup(). It should be possible to move the 2 functions
found there (mp_start() & mp_announce()) even further down the path once
we know exactly where that should be...

Help from: Peter Wemm <peter@spinner.dialix.com.au>


# 26102 24-May-1997 fsmp

Delay mp_start() till after the msgbuf is mapped. We really want to delay
it till even later but tss setup prevents that right now...


# 25985 21-May-1997 jdp

This commit affects ELF kernels only.

Remove "setdefs.h" and arrange to generate it automatically at
ELF kernel build time.

"gensetdefs.c" is a utility which scans a set of ELF object files
and outputs a line ``DEFINE_SET(name, length);'' for each linker
set that it finds. When generating an ELF kernel, this is run just
before the final link to generate "setdefs.h".

Remove the init_sets() function from "setdef0.c", and its call from
"machdep.c". Since "gensetdefs.c" calculates the length of each
set, it is no longer necessary in an ELF kernel to count the set
elements at kernel initialization time. Also remove "set_of_sets"
which was used for this purpose.

Link "setdef0" and "setdef1" into the kernel only if building for
ELF. Since init_sets() is no longer used, there is no need to link
them into an a.out kernel.


# 25711 11-May-1997 bde

Fixed initialization of ldt[]. Unused entries were garbage. A comment
was stale.

Fixed initialization of gdt[] for the BDE_DEBUGGER case. APM entries
clobbered debugger entries if the debugger was loaded (APM is incompatible
with BDE_DEBUGGER) and unused entries were garbage if the debugger wasn't
loaded.


# 25556 07-May-1997 peter

md_regs is struct trapframe * now, rather than int []
Remove TF_REGP() macro and use. The original reason (address space
problems due to having UPAGES in mapped into user space) is gone. It
looks cleaner without it.


# 25164 26-Apr-1997 peter

Man the liferafts! Here comes the long awaited SMP -> -current merge!

There are various options documented in i386/conf/LINT, there is more to
come over the next few days.

The kernel should run pretty much "as before" without the options to
activate SMP mode.

There are a handful of known "loose ends" that need to be fixed, but
have been put off since the SMP kernel is in a moderately good condition
at the moment.

This commit is the result of the tinkering and testing over the last 14
months by many people. A special thanks to Steve Passe for implementing
the APIC code!


# 25083 22-Apr-1997 jdp

Make the necessary changes so that an ELF kernel can be built. I
have successfully built, booted, and run a number of different ELF
kernel configurations, including GENERIC. LINT also builds and
links cleanly, though I have not tried to boot it.

The impact on developers is virtually nil, except for two things.
All linker sets that might possibly be present in the kernel must be
listed in "sys/i386/i386/setdefs.h". And all C symbols that are
also referenced from assembly language code must be listed in
"sys/i386/include/asnames.h". It so happens that failure to do
these things will have no impact on the a.out kernel. But it will
break the build of the ELF kernel.

The ELF bootloader works, but it is not ready to commit quite yet.


# 24852 13-Apr-1997 dyson

Decrease the amount of memory allocated for bouncing. This will
allow large systems to boot successfully with bounce buffers compiled
in. We are now limiting bounce space to 512K. The 8MB allocated for
a 512MB system is very bogus -- and that is now fixed.


# 24691 07-Apr-1997 peter

The biggie: Get rid of the UPAGES from the top of the per-process address
space. (!)

Have each process use the kernel stack and pcb in the kvm space. Since
the stacks are at a different address, we cannot copy the stack at fork()
and allow the child to return up through the function call tree to return
to user mode - create a new execution context and have the new process
begin executing from cpu_switch() and go to user mode directly.
In theory this should speed up fork a bit.

Context switch the tss_esp0 pointer in the common tss. This is a lot
simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer
to each process's tss since the esp0 pointer is a 32 bit pointer, and the
sd_base setting is split into three different bit sections at non-aligned
boundaries and requires a lot of twiddling to reset.

The 8K of memory at the top of the process space is now empty, and unmapped
(and unmappable, it's higher than VM_MAXUSER_ADDRESS).

Simplity the pmap code to manage process contexts, we no longer have to
double map the UPAGES, this simplifies and should measuably speed up fork().

The following parts came from John Dyson:

Set PG_G on the UPAGES that are now in kernel context, and invalidate
them when swapping them out.

Move the upages object (upobj) from the vmspace to the proc structure.

Now that the UPAGES (pcb and kernel stack) are out of user space, make
rfork(..RFMEM..) do what was intended by sharing the vmspace
entirely via reference counting rather than simply inheriting the mappings.


# 24690 07-Apr-1997 peter

No longer use an i386tss as the basis of our pcb - it wasn't particularly
convenient and makes life difficult for my next commit. We still need
an i386tss to point to for the tss slot in the gdt, so we use a common
tss shared between all processes.

Note that this is going to break debugging until this series of commits
is finished. core dumps will change again too. :-( we really need
a more modern core dump format that doesn't depend on the pcb/upages.

This change makes VM86 mode harder, but the following commits will remove
a lot of constraints for the VM86 system, including the possibility of
extending the pcb for an IO port map etc.

Obtained from: bde


# 24437 31-Mar-1997 dg

Changed the way that the exec image header is read to be filesystem-
centric rather than VM-centric to fix a problem with errors not being
detectable when the header is read.
Killed exech_map as a result of these changes.
There appears to be no performance difference with this change.


# 24342 28-Mar-1997 joerg

Something long overdue: compile inb() and outb() into the kernel as
functions if DDB is available. The remaining occurences are usually
only inlined and thus not available in DDB.

I'm sure Bruce will have 23 additions to these 30 lines of code, but
at least it's a starting point. ;-)


# 24283 25-Mar-1997 mpp

Change sigreturn() to return EFAULT if it is passed an
address outside of the process's address space.
Now it matches its man page :-). Closes PR# 2682.

Discussed with: bde
Submitted by: Jonathan Lemon <jlemon@americantv.com>


# 24203 24-Mar-1997 bde

Don't include <sys/ioctl.h> in the kernel. Stage 1: don't include
it when it is not used. In most cases, the reasons for including it
went away when the special ioctl headers became self-sufficient.


# 24112 22-Mar-1997 kato

Improved CPU identification and initialization routines. This
supports All Cyrix CPUs, IBM Blue Lightning CPU and NexGen (now AMD)
Nx586 CPU, and initialize special registers of Cyrix CPU and msr of
IBM Blue Lightning CPU.

If revision of Cyrix 6x86 CPU < 2.7, CPU cache is enabled in
write-through mode. This can be disabled by kernel configuration
options.

Reviewed by: Bruce Evans <bde@freebsd.org> and
Jordan K. Hubbard <jkh@freebsd.org>


# 23070 24-Feb-1997 alex

Typo police.


# 22975 22-Feb-1997 peter

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.


# 22521 10-Feb-1997 dyson

This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.

Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>


# 21975 24-Jan-1997 bde

Initialize CR0_MP in setregs() in case npx0 is disabled or not configured.
Disabling npx0 works right now.

Don't reference `npxdriver' if npx0 is not configured. Not configuring
npx0 doesn't quite work yet.

Don't clear potential non-npx pcb flags in setregs().


# 21737 15-Jan-1997 dg

Fix bug related to map entry allocations where a sleep might be attempted
when allocating memory for network buffers at interrupt time. This is due
to inadequate checking for the new mcl_map. Fixed by merging mb_map and
mcl_map into a single mb_map.

Reviewed by: wollman


# 21673 14-Jan-1997 jkh

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.


# 20998 29-Dec-1996 dyson

Superficial clean-up of useracc calls. (The useracc usage of
B_READ/B_WRITE is bogus anyway.) Might as well make the call prettier
anyway.


# 20641 18-Dec-1996 bde

Moved the printing of the BIOS geometries from cpu_startup() into
configure() where it always belonged. It was originally slightly
misplaced after configure(). Rev.138 left it completely misplaced
before the DEVFS, DRIVERS and CONFIGURE sysinits by not moving it
together with configure().

Restored the printing of bootinfo.bi_n_bios_used now that it can
be nonzero.


# 20578 17-Dec-1996 dg

Fix nbuf calculation /4 -> /8. 2.2 already has it this way.

Reviewed by: dyson


# 20471 14-Dec-1996 jkh

Make the USERCONFIG_BOOT semantics closer to what was original
intended.


# 20348 12-Dec-1996 dg

Fix allocation for exech_map to be 16*PAGE_SIZE rather than 32*PAGE_SIZE
so that it is scaled the same as exec_map (16 concurrent exec'ers).


# 20313 11-Dec-1996 dyson

One minor mod to set the limit of nbufs to 2048 from 1536. More important
fix to exech_map, it used 32*ARG_MAX, and it should use 32*PAGE_SIZE.


# 20146 05-Dec-1996 dyson

Clean-up of the new buffer kva allocation code. Also, there was an
error in the !BOUNCE_BUFFERS case.


# 20070 01-Dec-1996 bde

Removed all references to b_cylinder (aka b_cylin). It was evil and
hasn't been used for a year or two since disksort() started sorting
on b_pblkno.


# 20068 01-Dec-1996 dyson

Fix a problem with the new buffer_map management code. Additionally,
decrease the size of buffer_map to approx 2/3 of what it used to be
(buffer_map can be smaller now.) The original commit of these changes
increased the size of buffer_map to the point where the system would
not boot on large systems -- now large systems with large caches will
have even less problems than before.


# 20017 29-Nov-1996 bde

Don't print bootinfo.bi_n_bios_used in cpu_startup() since it is always
zero because no drivers have had a chance to change it.


# 20016 29-Nov-1996 bde

Don't clobber the SIGCONT bit in the signal mask in sigreturn(). Use
the `sigcantmask' macro to get the correct set of unmaskable signals.

Found by: NIST-PCTS.


# 19828 17-Nov-1996 dyson

Improve the caching of small files like directories, while not
substantially increasing buffer space. Specifically, we double
the number of buffers, but allocate only half the amount of memory
per buffer. Note that VDIR files aren't cached unless instantiated
in a buffer. This will significantly improve caching.


# 19653 11-Nov-1996 bde

Replaced I586_OPTIMIZED_BCOPY and I586_OPTIMIZED_BZERO with boot-time
negative-logic flags (flags 0x01 and 0x02 for npx0, defaulting to unset = on).
This changes the default from off to on. The options have been in current
for several months with no problems reported.

Added a boot-time negative-logic flag for the old I5886_FAST_BCOPY option
which went away too soon (flag 0x04 for npx0, defaulting to unset = on).

Added a boot-time way to set the memory size (iosiz in config, iosize in
userconfig for npx0).

LINT:
Removed old options. Documented npx0's flags and iosiz.

options.i386:
Removed old options.

identcpu.c:
Don't set the function pointers here. Setting them has to be delayed
until after userconfig has had a chance to disable them and until after
a good npx0 has been detected.

machdep.c:
Use npx0's iosize instead of MAXMEM if it is nonzero.

support.s:
Added vectors and glue code for copyin() and copyout().
Fixed ifdefs for i586_bzero().
Added ifdefs for i586_bcopy().

npx.c:
Set the function pointers here.
Clear hw_float when an npx exists but is too broken to use.
Restored style from a year or three ago in npxattach().


# 19503 07-Nov-1996 joerg

Fix the message buffer mapping. This actually allows to increase
the message buffer size in <sys/msgbuf.h>.

Reviewed by: davidg,joerg
Submitted by: bde


# 19274 31-Oct-1996 julian

Further improved version of hadling a HALT when there is no console.


# 19064 20-Oct-1996 phk

Removing old isdn stuff.


# 18702 05-Oct-1996 jkh

Multiple changes stacked as one commit since they all depend on one another.

First, change sysinstall and the Makefile rules to not build the kernel
nlist directly into sysinstall now. Instead, spit it out as an ascii
file in /stand and parse it from sysinstall later. This solves the chicken-n-
egg problem of building sysinstall into the fsimage before BOOTMFS is built
and can have its symbols extracted. Now we generate the symbol file in
release.8.

Second, add Poul-Henning's USERCONFIG_BOOT changes. These have two
effects:

1. Userconfig is always entered, rather than only after a -c
(don't scream yet, it's not as bad as it sounds).

2. Userconfig reads a message string which can optionally be
written just past the boot blocks. This string "preloads"
the userconfig input buffer and is parsed as user input.
If the first command is not "USERCONFIG", userconfig will
treat this as an implied "quit" (which is why you don't need
to scream - you never even know you went through userconfig
and back out again if you don't specifically ask for it),
otherwise it will read and execute the following commands
until a "quit" is seen or the end is reached, in which case
the normal userconfig command prompt will then be presented.

How to create your own startup sequences, using any boot.flp image
from the next snap forward (not yet, but soon):

% dd of=/dev/rfd0 seek=1 bs=512 count=1 conv=sync <<WAKKA_WAKKA_DOO
USERCONFIG
irq ed0 10
iomem ed0 0xcc000
disable ed1
quit
WAKKA_WAKKA_DOO


Third, add an intro screen to UserConfig so that users aren't just thrown
into this strange screen if userconfig is auto-launched. The default
boot.flp startup sequence is now, in fact, this:

USERCONFIG
intro
visual

(Since visual never returns, we don't need a following "quit").

Submitted-By: phk & jkh


# 18548 28-Sep-1996 dyson

Essentially rename pmap_update to be invltlb. It is a very machine
dependent operation, and not really a correct name. invltlb and invlpg
are more descriptive, and in the case of invlpg, a real opcode.

Additionally, fix the tlb management code for 386 machines.


# 18514 27-Sep-1996 peter

part 2 of the bsdi compat tweak attempt. I believe that BSDI use both
lcall 7,0 (ie: ldt slot 0) and lcall 0x87,0 (ldt slot 16, it's shifted
three bits to the left). I was fiddling with this so long ago, I don't
recall the specifics.


# 18252 11-Sep-1996 phk

Make userconfig two (default: on) options:
USERCONFIG to enable
VISUAL_USERCONFIG to get the gui stuff too.
Requested by: pst


# 18232 10-Sep-1996 bde

Removed bogus LARGMEM code and option. The code paniced when
biosextmem > 65536, but biosextmem is a 16-bit quantity so it is
guaranteed to be < 65536. Related cruft for biosbasemem was
mostly cleaned up in rev.1.26.


# 18084 06-Sep-1996 phk

Remove devconf, it never grew up to be of any use.


# 18023 03-Sep-1996 nate

Cleaned up version of my 'extended BIOS' patch. This one is commented
better and much simpler to understand, and works just as well (better)
as a bonus.

Submitted by: bde


# 17983 01-Sep-1996 nate

If the basemem value supplied by the bootblocks, differs from the value
returned by the RTC, use the bootblock supplied value. Also, map the
'stolen by BIOS' memory in the same manner as the ISA-hole memory, since
it is really an extenstion of the BIOS. This is necessary for 32-bit
BIOS functions such as APM support on laptops, and the loss of memory
for non-necessary functions seems to be at most 4k.

Reviewed by: phk
Obtained from: email conversation with jtk@atria.com


# 17677 19-Aug-1996 julian

Collect all the functioons concerned with rebooting into one place
also add the at_shutdown callout list, and change the one user of
the present (broken) method (the vn driver) to use the new scheme.


# 17559 12-Aug-1996 wollman

Back out mistaken local change that sneaked in on the last commit.


# 17558 12-Aug-1996 wollman

Don't declare the user_ldt functions unless USER_LDT is defined.
Eliminates an obnoxious warning.


# 17521 11-Aug-1996 dg

Add support for i686 machine check trap.


# 17118 12-Jul-1996 bde

Export `dumpmag' to utilities but not to the kernel.

Restored a truncated comment.


# 17014 08-Jul-1996 wollman

Fix something that's been bugging me for a long time: move the CPU
type identification code out of machdep.c and into a new file of its
own. Hopefully other grot can be moved out of machdep.c as well
(by other people) into more descriptively-named files.


# 16471 18-Jun-1996 bde

Removed unused #includes of <i386/isa/icu.h> and <i386/isa/icu.h>. icu.h
is only used by the icu support modules and by a few drivers that know
too much about the icu (most only use it to convert `n' to `IRQn'). isa.h
is only used by ioconf.c and by a few drivers that know too much about
isa addresses (a few have to, because config is deficient).


# 16215 08-Jun-1996 bde

Stop using the alias `pcb_ptd' for `pcb_tcc.tss_cr3'. Use the (existing)
alias `pcb_cr3' instead. That is still one alias too many, but is convenient
for me since I've replaced the tss in the pcb by a few scalar variables in
the pcb.


# 15809 18-May-1996 dyson

This set of commits to the VM system does the following, and contain
contributions or ideas from Stephen McKay <syssgm@devetir.qld.gov.au>,
Alan Cox <alc@cs.rice.edu>, David Greenman <davidg@freebsd.org> and me:

More usage of the TAILQ macros. Additional minor fix to queue.h.
Performance enhancements to the pageout daemon.
Addition of a wait in the case that the pageout daemon
has to run immediately.
Slightly modify the pageout algorithm.
Significant revamp of the pmap/fork code:
1) PTE's and UPAGES's are NO LONGER in the process's map.
2) PTE's and UPAGES's reside in their own objects.
3) TOTAL elimination of recursive page table pagefaults.
4) The page directory now resides in the PTE object.
5) Implemented pmap_copy, thereby speeding up fork time.
6) Changed the pv entries so that the head is a pointer
and not an entire entry.
7) Significant cleanup of pmap_protect, and pmap_remove.
8) Removed significant amounts of machine dependent
fork code from vm_glue. Pushed much of that code into
the machine dependent pmap module.
9) Support more completely the reuse of already zeroed
pages (Page table pages and page directories) as being
already zeroed.
Performance and code cleanups in vm_map:
1) Improved and simplified allocation of map entries.
2) Improved vm_map_copy code.
3) Corrected some minor problems in the simplify code.
Implemented splvm (combo of splbio and splimp.) The VM code now
seldom uses splhigh.
Improved the speed of and simplified kmem_malloc.
Minor mod to vm_fault to avoid using pre-zeroed pages in the case
of objects with backing objects along with the already
existant condition of having a vnode. (If there is a backing
object, there will likely be a COW... With a COW, it isn't
necessary to start with a pre-zeroed page.)
Minor reorg of source to perhaps improve locality of ref.


# 15722 10-May-1996 wollman

Allocate mbufs from a separate submap so that NMBCLUSTERS works as
expected.


# 15583 03-May-1996 phk

Another sweep over the pmap/vm macros, this time with more focus on
the usage. I'm not satisfied with the naming, but now at least there is
less bogus stuff around.


# 15565 02-May-1996 phk

Move atdevbase out of locore.s and into machdep.c
Macroize locore.s' page table setup even more, now it's almost readable.
Rename PG_U to PG_A (so that I can...)
Rename PG_u to PG_U. "PG_u" was just too ugly...
Remove some unused vars in pmap.c
Remove PG_KR and PG_KW
Remove SSIZE
Remove SINCR
Remove BTOPKERNBASE

This concludes my spring cleaning, modulus any bug fixes for messes I
have made on the way.

(Funny to be back here in pmap.c, that's where my first significant
contribution to 386BSD was... :-)


# 15543 02-May-1996 phk

removed:
CLBYTES PD_SHIFT PGSHIFT NBPG PGOFSET CLSIZELOG2 CLSIZE pdei()
ptei() kvtopte() ptetov() ispt() ptetoav() &c &c
new:
NPDEPG

Major macro cleanup.


# 15508 01-May-1996 bde

Added calibration the i8254 and the i586 clocks agains the RTC at boot
time. The results are currently ignored unless certain temporary options
are used.

Added sysctls to support reading and writing the clock frequency variables
(not the frequencies themselves). Writing is supposed to atomically
adjust all related variables.

machdep.c:
Fixed spelling of a function name in a comment so that I can log this
message which should have been with the previous commit.

Initialize `cpu_class' earlier so that it can be used in startrtclock()
instead of in calibrate_cyclecounter() (which no longer exists).

Removed range checking of `cpu'. It is always initialized to CPU_XXX
so it is less likely to be out of bounds than most variables.

clock.h:
Removed I586_CYCLECTR(). Use rdtsc() instead.

clock.c:
TIMER_FREQ is now a variable timer_freq that defaults to the old value of
TIMER_FREQ. #define'ing TIMER_FREQ should still work and may be the best
way of setting the frequency.

Calibration involves counting cycles while watching the RTC for one second.
This gives values correct to within (a few ppm) + (the innaccuracy of the
RTC) on my systems.


# 15507 01-May-1996 bde

i386/machdep.c
include/clock.h
isa/clock.c


# 15392 26-Apr-1996 phk

A significant debogofication of locore.s. I havn't found any actualy
bugs, but it is a lot easier to navigate this twisted code now.


# 15379 25-Apr-1996 phk

Fix cpu_fork for real.

Suggested by: bde


# 15304 19-Apr-1996 phk

savectx returns through cpu_switch in case of the child, so it must
return void just like cpu_switch. Fix prototype and usage from machdep.c


# 15065 06-Apr-1996 dg

Switch 586/686 back to generic_bzero and #if 0'd the "optimized" code. It
turns out that it actually reduces performance in real-world cases.

Noticed by: bde


# 15045 05-Apr-1996 ache

Add wall_cmos_clock sysctl variable, needed to manage adjkerntz even for
UTC cmos clocks (needed for Local Timezone FSes)


# 14825 26-Mar-1996 wollman

Add support for Pentium and Pentium Pro performance counters.
(This code is as yet untested; to come after man page is written.)
This also adds inlines to cpufunc.h for the RDTSC, RDMSR, WRMSR, and RDPMC
instructions. The user-mode interface is via a subdevice of mem.c;
there is also a kernel-size interface which might be used to aid
profiling.


# 14503 11-Mar-1996 hsu

Change type of code argument to sendsig from unsigned to u_long to make it
consistent w/ signalvar.h and kern_sig.c.
Reviewed by: davidg & bde


# 14348 03-Mar-1996 jkh

USER_LDT changes for the Willows TwinXPDK toolkit. Only tested with WINE
since that's the only other USER_LDT using code that I know of.
Submitted by: Gary Jennejohn <Gary.Jennejohn@munich.netsurf.de>
Obtained from: {Origin of diffs may be someone else - I only rec'd them from
Gary}


# 14331 02-Mar-1996 peter

Mega-commit for Linux emulator update.. This has been stress tested under
netscape-2.0 for Linux running all the Java stuff. The scrollbars are now
working, at least on my machine. (whew! :-)

I'm uncomfortable with the size of this commit, but it's too
inter-dependant to easily seperate out.

The main changes:

COMPAT_LINUX is *GONE*. Most of the code has been moved out of the i386
machine dependent section into the linux emulator itself. The int 0x80
syscall code was almost identical to the lcall 7,0 code and a minor tweak
allows them to both be used with the same C code. All kernels can now
just modload the lkm and it'll DTRT without having to rebuild the kernel
first. Like IBCS2, you can statically compile it in with "options LINUX".

A pile of new syscalls implemented, including getdents(), llseek(),
readv(), writev(), msync(), personality(). The Linux-ELF libraries want
to use some of these.

linux_select() now obeys Linux semantics, ie: returns the time remaining
of the timeout value rather than leaving it the original value.

Quite a few bugs removed, including incorrect arguments being used in
syscalls.. eg: mixups between passing the sigset as an int, vs passing
it as a pointer and doing a copyin(), missing return values, unhandled
cases, SIOC* ioctls, etc.

The build for the code has changed. i386/conf/files now knows how
to build linux_genassym and generate linux_assym.h on the fly.

Supporting changes elsewhere in the kernel:

The user-mode signal trampoline has moved from the U area to immediately
below the top of the stack (below PS_STRINGS). This allows the different
binary emulations to have their own signal trampoline code (which gets rid
of the hardwired syscall 103 (sigreturn on BSD, syslog on Linux)) and so
that the emulator can provide the exact "struct sigcontext *" argument to
the program's signal handlers.

The sigstack's "ss_flags" now uses SS_DISABLE and SS_ONSTACK flags, which
have the same values as the re-used SA_DISABLE and SA_ONSTACK which are
intended for sigaction only. This enables the support of a SA_RESETHAND
flag to sigaction to implement the gross SYSV and Linux SA_ONESHOT signal
semantics where the signal handler is reset when it's triggered.

makesyscalls.sh no longer appends the struct sysentvec on the end of the
generated init_sysent.c code. It's a lot saner to have it in a seperate
file rather than trying to update the structure inside the awk script. :-)

At exec time, the dozen bytes or so of signal trampoline code are copied
to the top of the user's stack, rather than obtaining the trampoline code
the old way by getting a clone of the parent's user area. This allows
Linux and native binaries to freely exec each other without getting
trampolines mixed up.


# 14328 02-Mar-1996 peter

Add more options into the conf/options and i386/conf/options.i386 files
and the #include hooks so that 'make depend' is more useful. This
covers most of the options I regularly use (but not all) and some other
easy ones.


# 14081 13-Feb-1996 phk

Correct & Update the printing of CPU features. We have printed rubbish
since version 1.117 when Garrett made the switch to %b. Updated to
reflect Intel AP-485 (241618-004).


# 13646 27-Jan-1996 bde

Allocate DMA bounce buffers only when requested by drivers. Only the
fd and wt drivers need bounce buffers, so this normally saves 32K-1K
of kernel memory.

Keep track of which DMA channels are busy. isa_dmadone() must now be
called when DMA has finished or been aborted.

Panic for unallocated and too-small (required) bounce buffers.

fd.c:
There will be new warnings about isa_dmadone() not being called after
DMA has been aborted.

sound/dmabuf.c:
isa_dmadone() needs more parameters than are available, so temporarily
use a new interface isa_dmadone_nobounce() to avoid having to worry
about panics for fake parameters. Untested.


# 13580 23-Jan-1996 dg

Simplified savectx() a little and fixed a bug that caused it to return
garbage in the child process rather than "1" like it is supposed to.

Reviewed by: bde


# 13543 21-Jan-1996 joerg

Initialize the cpu_class variable. This prevents i386 machines from
panicing with a privileged instruction fault early at boot time.
Submitted by: rock@wurzelausix.CS.Uni-SB.DE (D. Rock)


# 13490 19-Jan-1996 dyson

Eliminated many redundant vm_map_lookup operations for vm_mmap.
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
overhead for merged cache.
Efficiency improvement for vfs_cluster. It used to do alot of redundant
calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files. Additionally,
fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources. The pageout code
will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
buffers.


# 13265 05-Jan-1996 wollman

Convert BOUNCE_BUFFERS and BOUNCEPAGES to new option scheme.


# 13228 04-Jan-1996 wollman

Convert DDB to new-style option.


# 13226 04-Jan-1996 wollman

Convert SYSV IPC to new-style options. (I hope I got everything...)
The LKMs will need an extra file, to come later.


# 13125 30-Dec-1995 dg

In memory test, cast pointer as "volatile int *", not "int *" to make sure
that gcc doesn't cache the value used in the test. Pointed out by Erich
Boleyn <erich@uruk.org>.


# 13085 28-Dec-1995 dg

Made bzero a function vector and added a 586/686 optimized version of
bzero.
Deprecated blkclr (removed it).
Removed some old cruft from cpufunc.h.

The optimized bzero was submitted by Torbjorn Granlund <tege@matematik.su.se>
The kernel adaption and other changes by me.


# 13004 25-Dec-1995 dg

Fix typo in CPUCLASS.


# 13000 24-Dec-1995 dg

Add Pentium Pro CPU detection and special handling. For now, all the
optimizations we have for 586s also apply to 686s...this will be fine-
tuned in the future as appropriate.


# 12977 22-Dec-1995 bde

Increased the double fault stack size from 512 to PAGE_SIZE. This is
wasteful, but better than clobbering the variables below the stack.
About 300 bytes of variables were clobbered when I examined double
faults using ddb. Perhaps a page that is known not to be accessed by
the double fault handler could be used. Such pages are not easy to
find, since the double fault handler calls panic() which calls sync()
and possibly dumpsys().


# 12929 19-Dec-1995 dg

Implemented a (sorely needed for years) double fault handler to catch stack
overflows.
It sure would be nice if there was an unmapped page between the PCB and
the stack (and that the size of the stack was configurable!). With the
way things are now, the PCB will get clobbered before the double fault
handler gets control, making somewhat of a mess of things. Despite this,
it is still fairly easy to poke around in the overflowed stack to figure
out the cause.


# 12889 16-Dec-1995 peter

Catch a couple more null devsw dereferences...


# 12827 14-Dec-1995 peter

GENERIC/LINT: Remove redundant quoting on some option lines.
LINT: add a couple of new/missing/undocumented options
files.i386: add linux code so that you can compile a kernel with static
linux emulation ("options LINUX")
i386/*: use #if defined(COMPAT_LINUX) || defined(LINUX) to enable static
support of linux emulation (just like "IBCS2" makes ibcs2 static)

The main thing this is going to make obvious, is that the LINUX code
(when compiled from LINT) has a lot of warnings, some of which dont look
too pleasant..


# 12813 13-Dec-1995 julian

devsw tables are now arrays of POINTERS to struct [cb]devsw
seems to work hre just fine though I can't check every file
that changed due to limmited h/w, however I've checked enught to be petty
happy withe hte code..

WARNING... struct lkm[mumble] has changed
so it might be an idea to recompile any lkm related programs


# 12722 10-Dec-1995 phk

Staticize and cleanup.
remove a TON of #includes from machdep.


# 12701 09-Dec-1995 phk

Move sysctl machdep.consdev to cons.c


# 12662 07-Dec-1995 dg

Untangled the vm.h include file spaghetti.


# 12623 04-Dec-1995 phk

A major sweep over the sysctl stuff.

Move a lot of variables home to their own code (In good time before xmas :-)

Introduce the string descrition of format.

Add a couple more functions to poke into these marvels, while I try to
decide what the correct interface should look like.

Next is adding vars on the fly, and sysctl looking at them too.

Removed a tine bit of defunct and #ifdefed notused code in swapgeneric.


# 12533 29-Nov-1995 wollman

Fix Pentium CPU rate diagnosis:
- Don't print out meaningless iCOMP numbers, those are for droids.
- Use a shorter wait to determine clock rate to avoid deficiencies
in DELAY().
- Use a fixed-point representation with 8 bits of fraction to store
the rate and rationalize the variable name. It would be
possible to use even more fraction if it turns out to be
worthwhile (I rather doubt it).

The question of source code arrangement remains unaddressed.


# 12429 20-Nov-1995 phk

Mega commit for sysctl.
Convert the remaining sysctl stuff to the new way of doing things.
the devconf stuff is the reason for the large number of files.
Cleaned up some compiler warnings while I were there.


# 12290 14-Nov-1995 phk

Fix a couple of printfs.


# 12243 12-Nov-1995 phk

The entire sysctl callback to read/write version. I havn't tested this as
much as I'd like to, but the malloc stunt I tried for an interim for
sure does worse.
Now we can read and write from any kind of address-space, not only
user and kernel, using callbacks.
This may be over-generalization for now, but it's actually simpler.


# 12186 10-Nov-1995 phk

convert more sysctl variables.


# 12078 04-Nov-1995 markm

Remove the #ifdev DEVRANDOM's, as promised.

/dev/random is now a part of the kernel! you will need to make
the device in /dev: sh MAKEDEV random
and take a look at some test code in src/tools/test/random.


# 12008 02-Nov-1995 peter

When the sync-on-shutdown fails to clear all buffers, this bit of code
can print them out.
I have seen that MFS can leave BUSY buffers, preventing a clean reboot...


# 11963 31-Oct-1995 peter

Add a simplistic netisr register routine - I need this now for ppp-2.2.


# 11875 28-Oct-1995 markm

Theodore Ts'po's random number gernerator for Linux, ported by me.
This code will only be included in your kernel if you have
'options DEVRANDOM', but that will fall away in a couple of days.
Obtained from: Theodore Ts'o, Linux


# 11390 10-Oct-1995 bde

Include <sys/sysproto.h> so that machdep.c compiles cleanly again
(the prototype for sync() moved).

KNFize and otherwise clean up printing of BIOS geometries.

Add prototypes.

Continue cleaning up new init stuff.


# 10782 15-Sep-1995 dg

1) Killed 'BSDVM_COMPAT'.
2) Killed i386pagesperpage as it is not used by anything.
3) Fixed benign miscalculations in pmap_bootstrap().
4) Moved allocation of ISA DMA memory to machdep.c.
5) Removed bogus vm_map_find()'s in pmap_init() - the entire range was
already allocated kmem_init().
6) Added some comments.

virual_avail is still miscalculated NKPT*NBPG too large, but in order to
fix this properly requires moving the variable initialization into locore.s.
Some other day.


# 10666 10-Sep-1995 bde

Make pcvt and syscons live in the same kernel. If both are enabled, then
the first one in the config has priority. They can be switched using
userconfig().

i386/i386/conf.c:
Initialize the shared syscons/pcvt cdevsw entry to `nx'.

Add cdevsw registration functions.

Use devsw functions of the correct type if they exist.

i386/i386/cons.c:
Add renamed syscons entry points to constab.

i386/i386/cons.h:
Declare the renamed syscons entry points.

i386/i386/machdep.c:
Repeat console initialization after userconfig() in case the current
console has become wrong. This depends on cn functions not wiring down
anything important.

sys/conf.h:
Declare new functions.

i386/isa/isa.[ch]:
Add a function to decide which display driver has priority. Should be
done better.

i386/isa/syscons.c:
Rename pccn* -> sccn*.

Initialize CRTC start address in case the previous driver has moved it.

i386/isa/syscons.c, i386/isa/pcvt/*
Initialize the bogusly shared variable Crtat dynamically in case the
stored value was changed by the previous driver.

Initialize cdevsw table from a template.

Don't grab the console if another display driver has priority.

i386/isa/syscons.h, i386/isa/pcvt/pcvt_hdr.h:
Don't externally declare now-static cdevsw functions.

i386/isa/pcvt/pcvt_hdr.h:
Set the sensitive hardware flag so that pcvt doesn't always have lower
priority than syscons. This also fixes the "stupid" detection of the
display after filling the display with text.

i386/isa/pcvt/pcvt_out.c:
Don't be confused the off-screen cursor offset 0xffff set by syscons.

kern/subr_xxx.c:
Add enough nxio/nodev/null devsw functions of the correct type for syscons
and pcvt.


# 10653 09-Sep-1995 dg

Fixed init functions argument type - caddr_t -> void *. Fixed a couple of
compiler warnings.


# 10616 08-Sep-1995 dg

1) Really print 'real' memory - use Maxmem, not physmem.
2) Output K bytes instead of pages as this means something to more people.
3) Moved printf of avail memory to after vm_bounce_init() call so that
bounce buffers are included in the figure.
4) Killed initcpu(); it's an unused vestige from the VAX.


# 10594 06-Sep-1995 wpaul

Put back the "real memory =" printf() that vanished when the code to
handle holes in memory was added.


# 10537 03-Sep-1995 julian

devfs changes..
changes to allow devices that don't probe (e.g. /dev/mem)
to create devfs entries
this required giving 'configure' its own SYSINIT entry
so we could duck in just before it with a DEVFS init
and some device inits..
my devfs now looks like:
./misc
./misc/speaker
./misc/mem
./misc/kmem
./misc/null
./misc/zero
./misc/io
./misc/console
./misc/pcaudio
./misc/pcaudioctl
./disks
./disks/rfloppy
./disks/rfloppy/fd0.1440
./disks/rfloppy/fd1.1200
./disks/floppy
./disks/floppy/fd0.1440
./disks/floppy/fd1.1200
also some sligt cleanups.. DEVFS needs a lot of work
but I'm getting back to it..


# 10358 28-Aug-1995 julian

Reviewed by: julian with quick glances by bruce and others
Submitted by: terry (terry lambert)
This is a composite of 3 patch sets submitted by terry.
they are:
New low-level init code that supports loadbal modules better
some cleanups in the namei code to help terry in 16-bit character support
some changes to the mount-root code to make it a little more
modular..

NOTE: mounting root off cdrom or NFS MIGHT be broken as I haven't been able
to test those cases..

certainly mounting root of disk still works just fine..
mfs should work but is untested. (tomorrows task)

The low level init stuff includes a total rewrite of init_main.c
to make it possible for new modules to have an init phase by simply
adding an entry to a TEXT_SET (or is it DATA_SET) list. thus a new module can
be added to the kernel without editing any other files other than the
'files' file.


# 10126 20-Aug-1995 dg

Fixed a few bugs and annoyances with boot():

1) deal with cold flag better
2) check for key input more often
3) get rid of unused variables
4) minor formatting improvements


# 9759 29-Jul-1995 bde

Eliminate sloppy common-style declarations. There should be none left for
the LINT configuation.


# 9744 28-Jul-1995 dg

Fixed bug I introduced with the memory-size code rewrite that broke
floppy DMA buffers...use avail_start not "first". Removed duplicate
(and wrong) declaration of phys_avail[].

Submitted by: Bruce Evans, but fixed differently by me.


# 9578 19-Jul-1995 dg

Rewrote memory sizing code to generally deal with holes in extended memory.
This code change should allow certain Compaq machines with a 128K hole
at 16MB to work.


# 9546 16-Jul-1995 phk

Make the bootinfo structure visible from sysctl.
This can be used in libdisk to guess a better bios-geometry.


# 9507 13-Jul-1995 dg

NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct
proc or any VM system structure will have to be rebuilt!!!

Much needed overhaul of the VM system. Included in this first round of
changes:

1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
haspage, and sync operations are supported. The haspage interface now
provides information about clusterability. All pager routines now take
struct vm_object's instead of "pagers".

2) Improved data structures. In the previous paradigm, there is constant
confusion caused by pagers being both a data structure ("allocate a
pager") and a collection of routines. The idea of a pager structure has
escentially been eliminated. Objects now have types, and this type is
used to index the appropriate pager. In most cases, items in the pager
structure were duplicated in the object data structure and thus were
unnecessary. In the few cases that remained, a un_pager structure union
was created in the object to contain these items.

3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
be removed. For instance, vm_object_enter(), vm_object_lookup(),
vm_object_remove(), and the associated object hash list were some of the
things that were removed.

4) simple_lock's removed. Discussion with several people reveals that the
SMP locking primitives used in the VM system aren't likely the mechanism
that we'll be adopting. Even if it were, the locking that was in the code
was very inadequate and would have to be mostly re-done anyway. The
locking in a uni-processor kernel was a no-op but went a long way toward
making the code difficult to read and debug.

5) Places that attempted to kludge-up the fact that we don't have kernel
thread support have been fixed to reflect the reality that we are really
dealing with processes, not threads. The VM system didn't have complete
thread support, so the comments and mis-named routines were just wrong.
We now use tsleep and wakeup directly in the lock routines, for instance.

6) Where appropriate, the pagers have been improved, especially in the
pager_alloc routines. Most of the pager_allocs have been rewritten and
are now faster and easier to maintain.

7) The pagedaemon pageout clustering algorithm has been rewritten and
now tries harder to output an even number of pages before and after
the requested page. This is sort of the reverse of the ideal pagein
algorithm and should provide better overall performance.

8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
have been removed. Some other unnecessary casts have also been removed.

9) Some almost useless debugging code removed.

10) Terminology of shadow objects vs. backing objects straightened out.
The fact that the vm_object data structure escentially had this
backwards really confused things. The use of "shadow" and "backing
object" throughout the code is now internally consistent and correct
in the Mach terminology.

11) Several minor bug fixes, including one in the vm daemon that caused
0 RSS objects to not get purged as intended.

12) A "default pager" has now been created which cleans up the transition
of objects to the "swap" type. The previous checks throughout the code
for swp->pg_data != NULL were really ugly. This change also provides
the rudiments for future backing of "anonymous" memory by something
other than the swap pager (via the vnode pager, for example), and it
allows the decision about which of these pagers to use to be made
dynamically (although will need some additional decision code to do
this, of course).

13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
object" code has been removed. MAP_COPY was undocumented and non-
standard. It was furthermore broken in several ways which caused its
behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
continue to work correctly, but via the slightly different semantics
of MAP_PRIVATE.

14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
threads design can be worked around in other ways. Both #12 and #13
were done to simplify the code and improve readability and maintain-
ability. (As were most all of these changes)

TODO:

1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
this will reduce the vnode pager to a mere fraction of its current size.

2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
information provided by the new haspage pager interface. This will
substantially reduce the overhead by eliminating a large number of
VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
improved to provide both a "behind" and "ahead" indication of
contiguousness.

3) Implement the extended features of pager_haspage in swap_pager_haspage().
It currently just says 0 pages ahead/behind.

4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
via a much more general mechanism that could also be used for disk
striping of regular filesystems.

5) Do something to improve the architecture of vm_object_collapse(). The
fact that it makes calls into the swap pager and knows too much about
how the swap pager operates really bothers me. It also doesn't allow
for collapsing of non-swap pager objects ("unnamed" objects backed by
other pagers).


# 9345 28-Jun-1995 dg

Killed redundant vnode_pager_umount() call. This is already done at
FS unmount time.


# 9326 26-Jun-1995 bde

Partially fix `sysctl machdep.console_device'. The fix will be complete
when syscons stops mapping the console to minor MAXCONS. There is
usually no corresponding device in /dev, and the correct device has
minor 0.

cons.c:
Initialize cn_tty properly, so that CPU_CONSDEV can work.
Comment about too many variants of the console tty pointer.

machdep.c:
Return device NODEV and not error EFAULT when there is no console device.


# 8876 30-May-1995 rgrimes

Remove trailing whitespace.


# 8748 25-May-1995 dg

Made "NMBCLUSTERS" calculation dynamic and fixed bogus use of "NMBCLUSTERS"
in machdep.c (it should use the global nmbclusters). Moved the calculation
of nmbclusters into conf/param.c (same place where nmbclusters has always
been assigned), and made the calculation include an extra amount based
on "maxusers". NMBCLUSTERS can still be overrided in the kernel config
file as always, but this change will make that generally unnecessary. This
fixes the "bug" reports from people who have misconfigured kernels seeing
the network hang when the mbuf cluster pool runs out.

Reviewed by: John Dyson


# 8481 12-May-1995 wollman

The death of `options NODUMP'. Now the dump area can be dynamically
configured (and unconfigured) on the fly. A sysctl(3) MIB variable is
provided to inspect and modify the dump device setting.


# 8456 11-May-1995 rgrimes

Fix -Wformat warnings from LINT kernel.


# 8427 11-May-1995 wollman

Delete two debugging printfs that mistakenly crept in.


# 8426 11-May-1995 wollman

Make networking domains drop-ins, through the magic of GNU ld. (Some day,
there may even be LKMs.) Also, change the internal name of `unixdomain'
to `localdomain' since AF_LOCAL is now the preferred name of this family.
Declare netisr correctly and in the right place.


# 7994 22-Apr-1995 wpaul

Tiny printf formatting change: if we have no cpu_vendor or cpu_id info,
don't generate a newline. (Yeah, I'm picking nits, but that empty line
I get on my 386 just looks dumb, okay? :)


# 7930 18-Apr-1995 rgrimes

Reapply my fix for this:
Output the CPU features line during the probe on a seperate line, for
folks with lots of features the output use to wrap and look ugle.


# 7908 17-Apr-1995 phk

Print the BIOS geometries in a human-readable format.


# 7814 14-Apr-1995 wpaul

Hopefully I won't get flamed for this: insert a few more #if defined(I486_CPU)
and #if defined (I586_CPU) thingies into identifycpu() so that we only
compile in what's actually needed for a given CPU. So far as I can tell,
none of my 386 machines generate a cpu_vendor code, so I made the extra vendor
and feature line conditional on I486_CPU and I586_CPU. (Otherwise we
print out a blank line which looks silly.)


# 7792 13-Apr-1995 wpaul

This a subtle reminder to people that not everybody compiles their
kernels with 'options I586_CPU.'

The declaration for pentium_mhz is hidden inside an #ifdef I586_CPU,
but machdep.c refers to it whether I586_CPU is defined or not. This
temporary hack puts the offending code inside an #ifdef I586_CPU as
well so that a kernel without it will successfully compile.

I must emphasize the word 'temporary:' somebody needs to seriously
beat on the identifycpu() function with an #ifdef stick so that
I386_CPU, I486_CPU and I586_CPU will do the right things.


# 7780 12-Apr-1995 wollman

Add a class field to devconf and mst drivers.
For those where it was easy, drivers were also fixed to call
dev_attach() during probe rather than attach (in keeping with the
new design articulated in a mail message five months ago). For
a few that were really easy, correct state tracking was added as well.
The `fd' driver was fixed to correctly fill in the description.
The CPU identify code was fixed to attach a `cpu' device. The code
was also massively reordered to fill in cpu_model with somethingremotely
resembling what identifycpu() prints out. A few bytes saved by using
%b to format the features list rather than lots of ifs.


# 7644 06-Apr-1995 rgrimes

Output the CPU features line during the probe on a seperate line, for
folks with lots of features the output use to wrap and look ugle.

Reviewed by: phk


# 7103 17-Mar-1995 dg

Call dev_shutdownall() just after unmounting filesystems.


# 7090 16-Mar-1995 bde

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'. Fix all the bugs found. There were no serious
ones.


# 6949 07-Mar-1995 dg

Increased number of buffers to 1/12 of (page_count - 1024). This makes the
cache minimum closer to 10% in the usual case.


# 6846 03-Mar-1995 dg

Use copyout to install the sigframe rather than directly writing to the
user's stack.


# 6439 15-Feb-1995 dg

Use proc0's proc struct rather than curproc's when calling sync.


# 6380 14-Feb-1995 sos

First attempt to run linux binaries. This is only the changes needed to
the generic kernel. The actual emulator is a separate LKM. (not finished
yet, sorry).
Submitted by: sos@freebsd.org & sef@kithrup.com


# 6327 12-Feb-1995 dg

Carefully choose the low limit for number of buffers to acheive the best
performance on small memory machines.


# 6308 11-Feb-1995 phk

Intels App Note AP-485 applied.
We will now tell a good deal more about the CPU if Intel made it.

What is a i486DX2 Write-Back Enhanced CPU ?


# 6301 10-Feb-1995 dg

Changed extended memory test so that it's non-destructive and not a
complete test (it never was "complete", which is why it was bogus). Now
only a single longword is checked in each page.


# 6299 10-Feb-1995 dg

Removed obsolete and unused vmtime() function.


# 5999 29-Jan-1995 ats

Correct a name of one structure member in the sigaltstack structure.
Now it matches the man page and also the only other commercial implementation
i have found so far ( Solaris 2.x).
Changed the name from ss_base to ss_sp.


# 5908 25-Jan-1995 bde

Load the kernel symbol table in the boot loader and not at compile time.
(Boot with the -D flag if you want symbols.)

Make it easier to extend `struct bootinfo' without losing either forwards
or backwards compatibility.

ddb_aout.c:
Get the symbol table from wherever the loader put it.
Nuke db_symtab[SYMTAB_SPACE].

boot.c:
Enable loading of symbols. Align them on a page boundary. Add printfs
about the symbol table sizes.
Pass the memory sizes to the kernel.
Fix initialization of `unit' (it got moved out of the loop).
Fix adding the bss size (it got moved inside an ifdef).
Initialize serial port when RB_SERIAL is toggled on.
Fix comments.
Clean up formatting of recently added code.

io.c:
Clean up formatting of recently added code.

netboot/main.c, machdep.c, wd.c:
Change names of bootinfo fields.

LINT:
Nuke SYMTAB_SPACE.
Fix comment about DODUMP.

Makefile.i386:
Nuke use of dbsym.
Exclude gcc symbols from kernel unless compiling with -g.
Remove unused macro.
Fix comments and formatting.

genassym.c:
Generate defines for some new bootinfo fields. Change names of old ones.

locore.s:
Copy only the valid part of the `struct bootinfo' passed by the loader.
Reserve space for symbol table, if any.

machdep.c:
Check the memory sizes passed by the loader, if any. Don't use them yet.

bootinfo.h:
Add a size field so that we can resolve some mismatches between the loader
bootinfo and the kernel boot info. The version number is not so good for
this because of historical botches and because it's harder to maintain.
Add memory size and symbol table fields. Change the names of everything.

Hacks to save a few bytes:

asm.S, boot.c, boot2.S:
Replace `ouraddr' by `(BOOTSEG << 4)'.

boot.c:
Don't statically initialize `loadflags' to 0. Disable the "REDUNDANT"
code that skips the BIOS variables. Eliminate `total'. Combine some
more printfs.

boot.h, disk.c, io.c, table.c:
Move all statically initialzed data to table.c.

io.c:
Don't put the A20 gate bits in a variable.


# 5837 24-Jan-1995 dg

Changed buffer allocation policy (machdep.c)
Moved various pmap 'bit' test/set functions back into real functions; gcc
generates better code at the expense of more of it. (pmap.c)
Fixed a deadlock problem with pv entry allocations (pmap.c)
Added a new, optional function 'pmap_prefault' that does clustered page
table preloading (pmap.c)
Changed the way that page tables are held onto (trap.c).

Submitted by: John Dyson


# 5675 17-Jan-1995 bde

The %eflags checking introduced in the previous commit was too zealous.
sigreturn() sometimes failed for ordinary returns from signal handlers.
Failures of ordinary returns "can't happen" and are badly handled.
"Temporary" fix: allow users to corrupt PSL_RF. This is fairly
harmless. A correct fix would involve saving the old %eflags (and
perhaps the old segment registers) where the user can't get at them.


# 5603 14-Jan-1995 bde

Fix security holes in sigreturn(), ptrace() and procfs. sigreturn()
attempted to check for insecure and fatal eflags and segment
selectors, but missed many cases and got the IOPL check back to
front. The other syscalls didn't check at all.

sys_process.c, machdep.c:
Only allow PT_WRITE_U to write to the registers (ordinary and FP).

psl.h, locore.s, machdep.c:
Eliminate PSL_MBZ, PSL_MBO and PSL_USERCLR. We are not supposed
to assume anything about the reserved bits. Use PSL_USERCHANGE
and PSL_KERNEL instead. Rename PSL_USERSET to PSL_USER.

exception.s:
Define a private label for use by doreti when returning to user
mode fails.

machdep.c:
In syscalls, allow changing only the eflags that can be changed on
486's in user mode (no longer attempt to allow benign IOPL changes;
allow changing the nasty PSL_NT; don't allow changing the i586
bits).

Don't attempt to check all the cases involving invalid selectors
and %eip's. Just check for privilege violations and let the invalid
things cause a trap.

procfs_machdep.c:
Call the ptrace register functions to do all the work for reading
and writing ordinary registers and for single stepping.

trap.c:
Ignore traps caused by PSL_NT being set. Previously, users could
cause a fatal trap in user mode by setting PSL_NT and executing an
iret, and a fatal trap in kernel mode by setting PSL_NT and making
a syscall. PSL_NT was cleared too late and not in enough modes to
fix the problem.

Make all traps in user mode (except T_NMI) nonfatal.

Recover from traps caused by attempting to load invalid user
registers in doreti by restarting the traps so that they appear to
occur in user mode.
---

Fix bogons that I noticed while fixing the above:

psl.h:
Fix some comments.

Uniformize idempotency ifdef.

exception.s, machdep.c:
Remove rsvd[0-14]. rsvd0 hasn't been reserved since the 486 came
out. Replace rsvd0 by `align'. rsvd[0-11] used wrong (magic
non-unique) trap numbers. Replace rsvd[1-14] by rsvd.

locore.s:
Enable alignment check flag on 486's and 586's.

machdep.c:
Use a better type for kstack[].

Use TFREGP() to find the registers.

Reformat ptrace functions from SEF to something closer to KNF.

procfs_machdep.c:
The wrong pointer to the registers got fixed as a side effect.

Implement reading and writing of FP registers.

/proc/*/*regs now work (only) for processes that are in memory.

Clean up comments.

trap.c, trap.h:
Remove unused trap types.


# 5455 09-Jan-1995 dg

These changes embody the support of the fully coherent merged VM buffer cache,
much higher filesystem I/O performance, and much better paging performance. It
represents the culmination of over 6 months of R&D.

The majority of the merged VM/cache work is by John Dyson.

The following highlights the most significant changes. Additionally, there are
(mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to
support the new VM/buffer scheme.

vfs_bio.c:
Significant rewrite of most of vfs_bio to support the merged VM buffer cache
scheme. The scheme is almost fully compatible with the old filesystem
interface. Significant improvement in the number of opportunities for write
clustering.

vfs_cluster.c, vfs_subr.c
Upgrade and performance enhancements in vfs layer code to support merged
VM/buffer cache. Fixup of vfs_cluster to eliminate the bogus pagemove stuff.

vm_object.c:
Yet more improvements in the collapse code. Elimination of some windows that
can cause list corruption.

vm_pageout.c:
Fixed it, it really works better now. Somehow in 2.0, some "enhancements"
broke the code. This code has been reworked from the ground-up.

vm_fault.c, vm_page.c, pmap.c, vm_object.c
Support for small-block filesystems with merged VM/buffer cache scheme.

pmap.c vm_map.c
Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of
kernel PTs.

vm_glue.c
Much simpler and more effective swapping code. No more gratuitous swapping.

proc.h
Fixed the problem that the p_lock flag was not being cleared on a fork.

swap_pager.c, vnode_pager.c
Removal of old vfs_bio cruft to support the past pseudo-coherency. Now the
code doesn't need it anymore.

machdep.c
Changes to better support the parameter values for the merged VM/buffer cache
scheme.

machdep.c, kern_exec.c, vm_glue.c
Implemented a seperate submap for temporary exec string space and another one
to contain process upages. This eliminates all map fragmentation problems
that previously existed.

ffs_inode.c, ufs_inode.c, ufs_readwrite.c
Changes for merged VM/buffer cache. Add "bypass" support for sneaking in on
busy buffers.

Submitted by: John Dyson and David Greenman


# 5413 05-Jan-1995 se

Submitted by: Wolfgang Stanglmeier <wolf@dentaro.GUN.de>
Reviewed by: <wollman>
First hooks and defines for the ISDN driver,
that soon will see the light ...


# 5037 11-Dec-1994 dg

Removed inappropriate comment.


# 5036 11-Dec-1994 dg

Add additional comment.


# 5035 11-Dec-1994 dg

Fix bogus comment.


# 4829 27-Nov-1994 phk

I made a syntax error yesterday.
Submitted by: John Capo


# 4819 26-Nov-1994 phk

Set the bootverbose if so desired.
if (bootverbose)
Print the geometries the bios passes to us (through the bootblocks).


# 4517 16-Nov-1994 dg

Allow MAXMEM to be larger than the detected physical memory. This change
was supposed to have already been made, but got botched somewhere.
Don't clobber the last page of memory (where the message buffer is). Some
BIOS don't gratuitously wipe it out on reboot.


# 4501 15-Nov-1994 bde

Make gdt_segs[] public again for APM.

Make ldt[] public again and restore currentldt and _default_ldt for
USER_LDT.


# 4476 14-Nov-1994 bde

Oops, the previous commit got the diff for the log message instead of
the following.

Move declarations to and from <machine/segments.h>. Make segment stuff
static if possible.

Remove unused (although initialized) global variables _default_ldt,
currentldt, _gsel_tss (rename the latter to the auto variable
gtel_tss).

Use "correct" and consistent types for interrupt handlers.

Remove a mailing address from the code.

Fix type mismatches found by adding prototypes.


# 4475 14-Nov-1994 bde

(Bogus several hundred line diff for a log message deleted. See rev 1.91
for the intended log message. -DG)


# 4463 14-Nov-1994 bde

Undo a previous change. <sys/disklabel.h> was broken, not these files.


# 4221 07-Nov-1994 phk

Added a kernel variable, "dodump" defaulting to zero, which disables dumps.
Somebody should make a mib variable for it.
Just now it is pointless to dump the kernel, since we have nothing which
can read the dump.
Furthermore is should never be the default to dump.
options DODUMP
will enable dumps.


# 4201 06-Nov-1994 dg

Do a better job at preparing registers for the new process in setregs()
by setting them all to a known state.


# 4193 06-Nov-1994 bde

Nuke the losing version of microtime. The assembler version now works
for all reasonable HZ's. HZ > 1000 doesn't work because of sloppy
conversions in hzto() (division by (tick / 1000) == 0). This was
fixed in 1.1.5.

Eliminate some extern declarations by including the appropriate header
files that now contain appropriate declarations.


# 4116 03-Nov-1994 jkh

Unconditionalize USERCONFIG. Uh, thanks, David.


# 4038 01-Nov-1994 ache

Implement CPU_ADJKERNTZ in different way: call resettodr()
on writting this variable. adjkerntz pgm changes will follow.


# 3962 28-Oct-1994 jkh

From: fredriks@mcs.com (Lars Fredriksen)
...
It turns out that these files do not include <sys/dkbad.h> before
<sys/disklabel.h>.
Submitted by: fredriks


# 3940 27-Oct-1994 jkh

Julian Elischer's disklabel fixes.


# 3907 26-Oct-1994 jkh

Invoke userconfig() if kernel compiled with options USERCONFIG and
-c flag used.


# 3846 25-Oct-1994 dg

Allow MAXMEM kernel option to indicate more memory than is detected; it
previously could only be used to limit the amount of memory.


# 3844 25-Oct-1994 dg

Restricted maximum bufpages to 1500; this is required for machines >64MB
of memory to work without running out of kernel VM (and increasing it to
even more than it is now (96MB) is out of the question. Changed bufpages
calculation to allocation a little less bufer cache (16% of mem-2MB instead
of 20%); this is simply a better figure for most systems.


# 3728 20-Oct-1994 phk

Peter Dufaults comconsole changes.

Submitted by: Peter Dufault


# 3703 19-Oct-1994 wollman

Implement disk_externalize().


# 3682 18-Oct-1994 ache

Remove CPU_COLORDISP, GIO_COLOR now exists


# 3661 17-Oct-1994 ache

Ifdef color_display by NSC, pointed by Rod


# 3627 15-Oct-1994 ache

ADd CPU_COLORDISP sysctl to handle console display type


# 3502 10-Oct-1994 phk

minaddr #ifdef lost in previous commit. Sorry.


# 3489 10-Oct-1994 phk

locore.s: Made the APM stuff depend on NAPM > 0 rather than a separate
"APM" macro.
machdep.c: Made the APM-descriptors unconditional.
Bruce: if these still conflict with your debugger, please put in a reservation
for your debugger. These three desc. can be anywhere, as long as they are
contiguous, so just move them as needed.


# 3451 09-Oct-1994 dg

Got rid of map.h. It's a leftover from the rmap code, and we use rlists.
Changed swapmap into swaplist.


# 3367 04-Oct-1994 ache

Add code to handle CPU_DISRTCSET


# 3306 02-Oct-1994 phk

Unused variables, except one with a omnious comment.


# 3284 02-Oct-1994 rgrimes

1. Remove all references to cyloffset, it has been unused for some time.

2. New detection code so we know what boot code called us.

3. Remove old DISKLESS support code and halt if we are called by that boot
code as it will NOT work with the new nfs_diskless structure.

This is really in preperation for new boot code and new diskless support.

Reviewed by: davidg


# 3258 01-Oct-1994 dg

Laptop Advanced Power Management support by HOSOKAWA Tatsumi.

Submitted by: HOSOKAWA Tatsumi


# 3047 24-Sep-1994 dg

Nuked splnet before sync. Not only is this unnecessary, but it appears
to cause problems by making it impossible to sync NFS related buffers
when rebooting.


# 2822 16-Sep-1994 phk

Made the kernel compile even without "ether".


# 2818 16-Sep-1994 ache

CPU_ADJKERNTZ added to cpu_sysctl


# 2789 15-Sep-1994 dg

Brought over from 1.1.5:

Fix from Bruce Evans. There were missing sets of parantheses:

1. The checks for the standard data selectors were botched, so %ss == 0
and probably %cs == 0 were allowed. A fix is enclosed. The checks
for the standard selectors could be omitted without losing anything
since the standard selectors pass the valid_ldt_sel() tests.


# 2772 14-Sep-1994 wollman

Beginnings of support for loadable protocol domains. In particular,
don't hard-code netisr values in icu.s, but rather, use an array of
function pointers and set them all up in machdep.c for statically-linked
protocol families. (This will eventually be done differently.)


# 2495 04-Sep-1994 pst

Detect if we're running on a Cyrix 486DLC and enable automatic cache
negation whenever we access memory between 640k and 1M.

Original code from NetBSD 1.0-BETA. The exact origins are unclear but
Theo de Raadt, Charles, and Michael V. may have contributed to it.

Submitted by: pst


# 2455 02-Sep-1994 dg

Removed all vestiges of tlbflush(). Replaced them with calls to pmap_update().
Made pmap_update an inline assembly function.


# 2426 31-Aug-1994 dg

Fixed bug that surfaced with last commit for NOBOUNCE -> BOUNCE_BUFFERS by
adding appropriate #ifdefs and changing some variables to externs (as they
should have always been).


# 2422 31-Aug-1994 dg

Rather than exclude bounce buffers support with NOBOUNCE, include it
with BOUNCE_BUFFERS. This is more intuitive, and is better for future
multiplatform support. Added BOUNCE_BUFFERS option to the GENERIC and
LINT kernel config files.


# 2320 27-Aug-1994 dg

1) Changed ddb into a option rather than a pseudo-device (use options DDB
in your kernel config now).
2) Added ps ddb function from 1.1.5. Cleaned it up a bit and moved into its
own file.
3) Added \r handing in db_printf.
4) Added missing memory usage stats to statclock().
5) Added dummy function to pseudo_set so it will be emitted if there
are no other pseudo declarations.


# 2254 24-Aug-1994 sos

Changes preparing for iBCS2 support

Reviewed by:
Submitted by:


# 2152 20-Aug-1994 dg

Implemented filesystem clean bit via:

machdep.c:
Changed printf's a little and call vfs_unmountall() if the sync was
successful.

cd9660_vfsops.c, ffs_vfsops.c, nfs_vfsops.c, lfs_vfsops.c:
Allow dismount of root FS. It is now disallowed at a higher level.

vfs_conf.c:
Removed unused rootfs global.

vfs_subr.c:
Added new routines vfs_unmountall and vfs_unmountroot. Filesystems
are now dismounted if the machine is properly rebooted.

ffs_vfsops.c:
Toggle clean bit at the appropriate places. Print warning if an
unclean FS is mounted.

ffs_vfsops.c, lfs_vfsops.c:
Fix bug in selecting proper flags for VOP_CLOSE().

vfs_syscalls.c:
Disallow dismounting root FS via umount syscall.


# 2124 19-Aug-1994 dg

Terry Lambert's loadable kernel module support w/improvements from the
NetBSD group.


# 2112 18-Aug-1994 wollman

Fix up some sloppy coding practices:

- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.

NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.


# 2059 13-Aug-1994 dg

Made the kernel compile cleanly with gcc 2.6.0. Thanks go to Bruce
Evans for suggesting a method to detect various versions of gcc.


# 2056 13-Aug-1994 wollman

Change all #includes to follow the current Berkeley style. Some of these
``changes'' are actually not changes at all, but CVS sometimes has trouble
telling the difference.

This also includes support for second-directory compiles. This is not
quite complete yet, as `config' doesn't yet do the right thing. You can
still make it work trivially, however, by doing the following:

rm /sys/compile
mkdir /usr/obj/sys/compile
ln -s M-. /sys/compile
cd /sys/i386/conf
config MYKERNEL
cd ../../compile/MYKERNEL
ln -s /sys @
rm machine
ln -s @/i386/include machine
make depend
make


# 2014 10-Aug-1994 wollman

Tell Pentium users their CPU speed. (More changes to make use of this
to come later.)


# 1999 10-Aug-1994 wollman

Some programs (like GNU configure programs) depend on the output of
`uname -s' to be something reasonable (traditionally, `i386') rather
than `PC-Class'. Make it so.


# 1998 10-Aug-1994 wollman

Add back in CPU detection copde from 1.1.5. As an added bonus, the
hw.model MIB variable is now declared correctly.


# 1887 06-Aug-1994 dg

Incorporated post 1.1.5 work from John Dyson. This includes performance
improvements via the new routines pmap_qenter/pmap_qremove and pmap_kenter/
pmap_kremove. These routine allow fast mapping of pages for those
architectures that have "normal" MMUs. Also included is a fix to the
pageout daemon to properly check a queue end condition.

Submitted by: John Dyson


# 1829 04-Aug-1994 dg

Nuked #if 0'd _insque and _remque routines - they are now inlined in
cpufunc.h.


# 1825 03-Aug-1994 dg

Merged in post-1.1.5 work done by myself and John Dyson. This includes:

me:
1) TLB flush optimization that effectively eliminates half of all of the
TLB flushes. This works by only flushing the TLB when a page is "present"
in memory (i.e. the valid bit is set in the page table entry). See section
5.3.5 of the Intel 386 Programmer's Reference Manual.
2) The handling of "CMAP" has been improved to catch attempts at multiple
simultaneous use.

John:
1) Added pmap_qenter/pmap_qremove functions for fast mapping of pages into
the kernel. This is for future optimizations and support for the upcoming
merged VM/buffer cache.

Reviewed by: John Dyson


# 1678 04-Jun-1994 dg

Removed extra (bogus) declaration of Xrsvd14 that was confusing me.


# 1549 25-May-1994 rgrimes

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman


# 1321 02-Apr-1994 dg

New interrupt code from Bruce Evans. In additional to Bruce's attached
list of changes, I've made the following additional changes:

1) i386/include/ipl.h renamed to spl.h as the name conflicts with the
file of the same name in i386/isa/ipl.h.
2) changed all use of *mask (i.e. netmask, biomask, ttymask, etc) to
*_imask (net_imask, etc).
3) changed vestige of splnet use in if_is to splimp.
4) got rid of "impmask" completely (Bruce had gotten rid of netmask),
and are now using net_imask instead.
5) dozens of minor cruft to glue in Bruce's changes.

These require changes I made to config(8) as well, and thus it must
be rebuilt.

-DG

from Bruce Evans:

sio:
o No diff is supplied. Remove the define of setsofttty(). I hope
that is enough.

*.s:
o i386/isa/debug.h no longer exists. The event counters became too
much trouble to maintain. All function call entry and exception
entry counters can be recovered by using profiling kernel (the new
profiling supports all entry points; however, it is too slow to
leave enabled all the time; it also). Only BDBTRAP() from debug.h
is now used. That is moved to exception.s. It might be worth
preserving SHOW_BITS() and calling it from _mcount() (if enabled).
o T_ASTFLT is now only set just before calling trap().
o All exception handlers set SWI_AST_MASK in cpl as soon as possible
after entry and arrange for _doreti to restore it atomically with
exiting. It is not possible to set it atomically with entering
the kernel, so it must be checked against the user mode bits in
the trap frame before committing to using it. There is no place
to store the old value of cpl for syscalls or traps, so there are
some complications restoring it.

Profiling stuff (mostly in *.s):
o Changes to kern/subr_mcount.c, gcc and gprof are not supplied yet.
o All interesting labels `foo' are renamed `_foo' and all
uninteresting labels `_bar' are renamed `bar'. A small change
to gprof allows ignoring labels not starting with underscores.
o MCOUNT_LABEL() is to provide names for counters for times spent
in exception handlers.
o FAKE_MCOUNT() is a version of MCOUNT() suitable for exception
handlers. Its arg is the pc where the exception occurred. The
new mcount() pretends that this was a call from that pc to a
suitable MCOUNT_LABEL().
o MEXITCOUNT is to turn off any timer started by MCOUNT().

/usr/src/sys/i386/i386/exception.s:
o The non-BDB BPTTRAP() macros were doing a sti even when interrupts
were disabled when the trap occurred. The sti (fixed) sti is
actually a no-op unless you have my changes to machdep.c that make
the debugger trap gates interrupt gates, but fixing that would
make the ifdefs messier. ddb seems to be unharmed by both
interrupts always disabled and always enabled (I had the branch in
the fix back to front for some time :-().
o There is no known pushal bug.
o tf_err can be left as garbage for syscalls.

/usr/src/sys/i386/i386/locore.s:
o Fix and update BDE_DEBUGGER support.
o ENTRY(btext) before initialization was dangerous.
o Warm boot shot was longer than intended.

/usr/src/sys/i386/i386/machdep.c:
o DON'T APPLY ALL OF THIS DIFF. It's what I'm using, but may require
other changes.
Use the following:
o Remove aston() and setsoftclock().
Maybe use the following:
o No netisr.h.
o Spelling fix.
o Delay to read the Rebooting message.
o Fix for vm system unmapping a reduced area of memory
after bounds_check_with_label() reduces the size of
a physical i/o for a partition boundary. A similar
fix is required in kern_physio.c.
o Correct use of __CONCAT. It never worked here for non-
ANSI cpp's. Is it time to drop support for non-ANSI?
o gdt_segs init. 0xffffffffUL is bogus because ssd_limit
is not 32 bits. The replacement may have the same
value :-), but is more natural.
o physmem was one page too low. Confusing variable names.
Don't use the following:
o Better numbers of buffers. Each 8K page requires up to
16 buffer headers. On my system, this results in 5576
buffers containing [up to] 2854912 bytes of memory.
The usual allocation of about 384 buffers only holds
192K of disk if you use it on an fs with a block size
of 512.
o gdt changes for bdb.
o *TGT -> *IDT changes for bdb.
o #ifdefed changes for bdb.

/usr/src/sys/i386/i386/microtime.s:
o Use the correct asm macros. I think asm.h was copied from Mach
just for microtime and isn't used now. It certainly doesn't
belong in <sys>. Various macros are also duplicated in
sys/i386/boot.h and libc/i386/*.h.
o Don't switch to and from the IRR; it is guaranteed to be selected
(default after ICU init and explicitly selected in isa.c too, and
never changed until the old microtime clobbered it).

/usr/src/sys/i386/i386/support.s:
o Non-essential changes (none related to spls or profiling).
o Removed slow loads of %gs again. The LDT support may require
not relying on %gs, but loading it is not the way to fix it!
Some places (copyin ...) forgot to load it. Loading it clobbers
the user %gs. trap() still loads it after certain types of
faults so that fuword() etc can rely on it without loading it
explicitly. Exception handlers don't restore it. If we want
to preserve the user %gs, then the fastest method is to not
touch it except for context switches. Comparing with
VM_MAXUSER_ADDRESS and branching takes only 2 or 4 cycles on
a 486, while loading %gs takes 9 cycles and using it takes
another.
o Fixed a signed branch to unsigned.

/usr/src/sys/i386/i386/swtch.s:
o Move spl0() outside of idle loop.
o Remove cli/sti from idle loop. sw1 does a cli, and in the
unlikely event of an interrupt occurring and whichqs becoming
zero, sw1 will just jump back to _idle.
o There's no spl0() function in asm any more, so use splz().
o swtch() doesn't need to be superaligned, at least with the
new mcounting.
o Fixed a signed branch to unsigned.
o Removed astoff().

/usr/src/sys/i386/i386/trap.c:
o The decentralized extern decls were inconsistent, of course.
o Fixed typo MATH_EMULTATE in comments. */
o Removed unused variables.
o Old netmask is now impmask; print it instead. Perhaps we
should print some of the new masks.
o BTW, trap() should not print anything for normal debugger
traps.

/usr/src/sys/i386/include/asmacros.h:
o DON'T APPLY ALL OF THIS DIFF. Just use some of the null macros
as necessary.

/usr/src/sys/i386/include/cpu.h:
o CLKF_BASEPRI() changes since cpl == SWI_AST_MASK is now normal
while the kernel is running.
o Don't use var++ to set boolean variables. It fails after a mere
4G times :-) and is slower than storing a constant on [3-4]86s.

/usr/src/sys/i386/include/cpufunc.h:
o DON'T APPLY ALL OF THIS DIFF. You need mainly the include of
<machine/ipl.h>. Unfortunately, <machine/ipl.h> is needed by
almost everything for the inlines.

/usr/src/sys/i386/include/ipl.h:
o New file. Defines spl inlines and SWI macros and declares most
variables related to hard and soft interrupt masks.

/usr/src/sys/i386/isa/icu.h:
o Moved definitions to <machine/ipl.h>

/usr/src/sys/i386/isa/icu.s:
o Software interrupts (SWIs) and delayed hardware interrupts (HWIs)
are now handled uniformally, and dispatching them from splx() is
more like dispatching them from _doreti. The dispatcher is
essentially *(handler[ffs(ipending & ~cpl)]().
o More care (not quite enough) is taken to avoid unbounded nesting
of interrupts.
o The interface to softclock() is changed so that a trap frame is
not required.
o Fast interrupt handlers are now handled more uniformally.
Configuration is still too early (new handlers would require
bits in <machine/ipl.h> and functions to vector.s).
o splnnn() and splx() are no longer here; they are inline functions
(could be macros for other compilers). splz() is the nontrivial
part of the old splx().

/usr/src/sys/i386/isa/ipl.h
o New file. Supposed to have only bus-dependent stuff. Perhaps
the h/w masks should be declared here.

/usr/src/sys/i386/isa/isa.c:
o DON'T APPLY ALL OF THIS DIFF. You need only things involving
*mask and *MASK and comments about them. netmask is now a pure
software mask. It works like the softclock mask.

/usr/src/sys/i386/isa/vector.s:
o Reorganize AUTO_EOI* macros.
o Option FAST_INTR_HANDLER_USERS_ES for people who don't trust
fastintr handlers.
o fastintr handlers need to metamorphose into ordinary interrupt
handlers if their SWI bit has become set. Previously, sio had
unintended latency for handling output completions and input
of SLIP framing characters because this was not done.

/usr/src/sys/net/netisr.h:
o The machine-dependent stuff is now imported from <machine/ipl.h>.

/usr/src/sys/sys/systm.h
o DON'T APPLY ALL OF THIS DIFF. You need mainly the different
splx() prototype. The spl*() prototypes are duplicated as
inlines in <machine/ipl.h> but they need to be duplicated here
in case there are no inlines. I sent systm.h and cpufunc.h
to Garrett. We agree that spl0 should be replaced by splnone
and not the other way around like I've done.

/usr/src/sys/kern/kern_clock.c
o splsoftclock() now lowers cpl so the direct call to softclock()
works as intended.
o softclock() interface changed to avoid passing the whole frame
(some machines may need another change for profile_tick()).
o profiling renamed _profiling to avoid ANSI namespace pollution.
(I had to improve the mcount() interface and may as well fix it.)
The GUPROF variant doesn't actually reference profiling here,
but the 'U' in GUPROF should mean to select the microtimer
mcount() and not change the interface.


# 1313 30-Mar-1994 dg

Eliminated the "physstrat" wart and merged it into kern_physio.c. This
patch also fixes a bug which causes a kernel VM leak.


# 1298 23-Mar-1994 dg

Bounce buffers. From John Dyson with help from me.


# 1281 19-Mar-1994 wollman

Added cpu_model and machine variables.


# 1247 07-Mar-1994 dg

1) enhanced in_cksum from Bruce Evans.
2) minor comment change in machdep.c
3) enhanced bzero from John Dyson (twice as fast on a 486DX/33)


# 1208 24-Feb-1994 hsu

validate sigcontext before restoring it


# 1129 08-Feb-1994 dg

From: Dave Matthews <dave@prlng.co.uk>

Description:
The integer overflow instruction (into) and the interrupt instruction with
value 4 (int #4) both give rise to SIGBUS signals rather than SIGFPE. The
problem is that overflow is a trap not a fault (unlike the BOUND instruction).


# 1127 08-Feb-1994 dg

Fixed bugs in stack grow code, and moved it back into a seperate function
like it was originally. Also added back call to "grow" in sendsig now
that this routine actually works.


# 1116 07-Feb-1994 dg

Fixed calculation of physmem when the special MAXMEM kernel config overide
is used. This bug caused the buffer cache to be WAY too big when memory
was being restricted - resulting in hangs and other out of memory problems.


# 1066 01-Feb-1994 dg

Bug fix from previous WINE commit. From Jeffrey Hsu.


# 1055 31-Jan-1994 dg

Added four pattern memory test routine that is done at startup.


# 1051 31-Jan-1994 dg

WINE/user LDT support from John Brezak, ported to FreeBSD by Jeffrey Hsu
<hsu@soda.berkeley.edu>.


# 1045 31-Jan-1994 dg

VM system performance improvements from John Dyson and myself. The
following is a summary:

1) increased object cache back up to a more reasonable value.
2) removed old & bogus cruft from machdep.c (clearseg, copyseg,
physcopyseg, etc).
3) inlined many functions in pmap.c
4) changed "load_cr3(rcr3())" into tlbflush() and made tlbflush inline
assembly.
5) changed the way that modified pages are tracked - now vm_page struct
is kept updated directly - no more scanning page tables.
6) removed lots of unnecessary spl's
7) removed old unused functions from pmap.c
8) removed all use of page_size, page_shift, page_mask variables - replaced
with PAGE_ constants.
9) moved trunc/round_page, atop, ptoa, out of vm_param.h and into i386/
include/param.h, and optimized them.
10) numerous changes to sys/vm/ swap_pager, vnode_pager, pageout, fault
code to improve performance. LRU algorithm modified to be more
effective, read ahead/behind values tuned for better performance,
etc, etc...


# 990 21-Jan-1994 dg

System V IPC code from Danny Boulet, chewed on a bit by the NetBSD group
and then some more by Jeffrey Hsu (who provided this port for FreeBSD).


# 989 20-Jan-1994 dg

Pointed out by Wolfgang Solfrank:
Correct parameters of sync


# 988 20-Jan-1994 dg

Removed some more old unused code/comments. Added hack to "fix" the
problem with some chipsets (UMC) remapping the 'hole' memory even when
you've got 16MB. People were led to believe that since there was only
16MB of memory in the machine, that they were okay wrt the ISA DMA
limit. This hack simply causes the extra memory to be ignored if it
appears around the 16MB limit.


# 987 20-Jan-1994 dg

Improved algorithm that calculates the pages in the base memory - If the
BIOS says that the amount is *between* 0-640K, believe it. Cleaned up
the comments a bit, removed some old cruff, etc.


# 974 14-Jan-1994 dg

"New" VM system from John Dyson & myself. For a run-down of the
major changes, see the log of any effected file in the sys/vm
directory (swap_pager.c for instance).


# 924 03-Jan-1994 dg

Convert syscall to trapframe. Based on work done by John Brezak.


# 911 22-Dec-1993 dg

Raised minimum buffer cache from 128k to 256k.


# 879 19-Dec-1993 wollman

Make everything compile with -Wtraditional. Make it easier to distribute
a binary link-kit. Make all non-optional options (pagers, procfs) standard,
and update LINT to reflect new symtab requirements.

NB: -Wtraditional will henceforth be forgotten. This editing pass was
primarily intended to detect any constructions where the old code might
have been relying on traditional C semantics or syntax. These were all
fixed, and the result of fixing some of them means that -Wall is now a
realistic possibility within a few weeks.


# 849 12-Dec-1993 dg

1) Added proc file system from Paul Kranenburg with changes from
John Dyson to make it reliably work under FreeBSD.
2) Added and enabled PROCFS in the GENERICxx and LINT kernels.
3) New execve() from me. Still work to be done here, but this version
works well and is needed before other changes can be made. For
a description of the design behind this, see freebsd-arch or
ask me.
4) Rewrote stack fault code; made user stack VM grow as needed rather
than all up front; improves performance a little and reduces
process memory requirements.
5) Incorporated fix from Gene Stark to fault/wire a user page table
page to fix a problem in copyout. This is a temporary fix and
is not appropriate for pageable page tables. For a description
of the problem, see Gene's post to the freebsd-hackers mailing
list.
6) Tighten up vm_page struct to reduce memory requirements for it. ifdef
pager page lock code as it's not being used currently.
7) Introduced new element to vmspace struct - vm_minsaddr; initial
(minimum) stack address. Compliment to vm_maxsaddr.
8) Added a panic if the allocation for process u-pages fails.
9) Improve performance and accuracy of kernel profiling by putting in
a little inline assembly instead of spl().
10) Made serial console with sio driver work. Still has problems with
serial input, but is almost useable.
11) Added -Bstatic to SYSTEM_LD in Makefile.i386 so that kernels will
build properly with the new ld.


# 827 03-Dec-1993 alm

From: Jeffrey Hsu <hsu@soda.berkeley.edu>

The following patch adds the addr argument to signal handlers.

The kernel with the patch is no more and no less in compliance or in
violation of POSIX and ANSI C than the kernel before the patch.

The added functionality this addr argument provides is quite useful. It
enables an entire class of algorithms which use mprotect to trace memory
references. Beside garbage collectors, I have heard of this technique being
applied to debuggers and profilers. The only benchmarking I've performed is
using akcl to compile maxima: without the kernel patch, it takes 7 hours to
compile maxima, while with stratified garbage collection, it only takes 50
minutes.

Basically, I can't think of a reason not to add the addr argument and there
is a compelling need for it.

If you find the patch acceptable, please let me know so I can send my
FreeBSD akcl config files to wfs for inclusion in the core akcl release.
The old 386BSD config files there won't work on either NetBSD or FreeBSD.


# 798 25-Nov-1993 wollman

Make the LINT kernel compile with -W -Wreturn-type -Wcomment -Werror, and
add same (sans -Werror) to Makefile for future compilations.


# 778 17-Nov-1993 wollman

Fixed comments that start within a comment, so code compiles cleanly with
-Wcomment.


# 774 16-Nov-1993 dg

new process tracing code from Sean Eric Fagen (sef@kithrup.com).
...also, fixed up the syscall args to make GCC happy.


# 757 13-Nov-1993 dg

First steps in rewriting locore.s, and making info useful
when the machine panics.

i386/i386/locore.s:
1) got rid of most .set directives that were being used like
#define's, and replaced them with appropriate #define's in
the appropriate header files (accessed via genassym).
2) added comments to header inclusions and global definitions,
and global variables
3) replaced some hardcoded constants with cpp defines (such as
PDESIZE and others)
4) aligned all comments to the same column to make them easier to
read
5) moved macro definitions for ENTRY, ALIGN, NOP, etc. to
/sys/i386/include/asmacros.h
6) added #ifdef BDE_DEBUGGER around all of Bruce's debugger code
7) added new global '_KERNend' to store last location+1 of kernel
8) cleaned up zeroing of bss so that only bss is zeroed
9) fix zeroing of page tables so that it really does zero them all
- not just if they follow the bss.
10) rewrote page table initialization code so that 1) works correctly
and 2) write protects the kernel text by default
11) properly initialize the kernel page directory, upages, p0stack PT,
and page tables. The previous scheme was more than a bit
screwy.
12) change allocation of virtual area of IO hole so that it is
fixed at KERNBASE + 0xa0000. The previous scheme put it
right after the kernel page tables and then later expected
it to be at KERNBASE +0xa0000
13) change multiple bogus settings of user read/write of various
areas of kernel VM - including the IO hole; we should never
be accessing the IO hole in user mode through the kernel
page tables
14) split kernel support routines such as bcopy, bzero, copyin,
copyout, etc. into a seperate file 'support.s'
15) split swtch and related routines into a seperate 'swtch.s'
16) split routines related to traps, syscalls, and interrupts
into a seperate file 'exception.s'
17) remove some unused global variables from locore that got
inserted by Garrett when he pulled them out of some .h
files.

i386/isa/icu.s:
1) clean up global variable declarations
2) move in declaration of astpending and netisr

i386/i386/pmap.c:
1) fix calculation of virtual_avail. It previously was calculated
to be right in the middle of the kernel page tables - not
a good place to start allocating kernel VM.
2) properly allocate kernel page dir/tables etc out of kernel map
- previously only took out 2 pages.

i386/i386/machdep.c:
1) modify boot() to print a warning that the system will reboot in
PANIC_REBOOT_WAIT_TIME amount of seconds, and let the user
abort with a key on the console. The machine will wait for
ever if a key is typed before the reboot. The default is
15 seconds, but can be set to 0 to mean don't wait at all,
-1 to mean wait forever, or any positive value to wait for
that many seconds.
2) print "Rebooting..." just before doing it.

kern/subr_prf.c:
1) remove PANICWAIT as it is deprecated by the change to machdep.c

i386/i386/trap.c:
1) add table of trap type strings and use it to print a real trap/
panic message rather than just a number. Lot's of work to
be done here, but this is the first step. Symbolic traceback
is in the TODO.

i386/i386/Makefile.i386:
1) add support in to build support.s, exception.s and swtch.s

...and various changes to various header files to make all of the
above happen.


# 724 07-Nov-1993 wollman

Get rid of WFJ's use of sleep() for more user-friendly tsleep().


# 683 29-Oct-1993 dg

Whoops, the algorithm I last used was messed up - I left off parans, and
should have used PGSHIFT instead of PAGE_SHIFT.


# 682 29-Oct-1993 dg

Change filesystem buffer cache size calculation to be less for 4MB
machines (now 20% of all memory after the first 3MB). This is necessary
in order for 4MB machine to be able to rebuild the entire source tree
and not run out of physical memory because of fixed memory requirements
of processes and kernel VM.


# 608 15-Oct-1993 rgrimes

genassym.c:
Remove NKMEMCLUSTERS, it is no longer define or used.

locores.s:
Fix comment on PTDpde and APTDpde to be pde instead of pte
Add new equation for calculating location of Sysmap
Remove Bill's old #ifdef garbage for counting up memory,
that stuff will never be made to work and was just cluttering
up the file.

Add code that places the PTD, page table pages, and kernel
stack below the 640k ISA hole if there is room for it, otherwise
put this stuff all at 1MB. This fixes the 28K bogusity in
the boot blocks, that can now go away!

Fix the caclulation of where first is to be dependent on
NKPDE so that we can skip over the above mentioned areas.
The 28K thing is now 44K in size due to the increase in
kernel virtual memory space, but since we no longer have
to worry about that this is no big deal.

Use if NNPX > 0 instead of ifdef NPX for floating point code.

machdep.c
Change the calculation of for the buffer cache to be
20% of all memory above 2MB and add back the upper limit
of 2/5's of the VM_KMEM_SIZE so that we do not eat ALL
of the kernel memory space on large memory machines, note
that this will not even come into effect unless you have
more than 32MB. The current buffer cache limit is 6.7MB
due to this caclulation.

It seems that we where erroniously allocating bufpages pages
for buffer_map. buffer_map is UNUSED in this implementation
of the buffer cache, but since the map is referenced in
several if statements a quick fix was to simply allocate
1 vm page (but no real memory) to it.

pmap.h
Remove rcsid, don't want them in the kernel files!

Removed some cruft inside an #ifdef DEBUGx that caused
compiler errors if you where compiling this for debug.

Use the #defines for PD_SHIFT and PG_SHIFT in place of
constants.

trap.c:
Remove patch kit header and rcsid, fix $Id$.
Now include "npx.h" and use NNPX for controlling the
floating point code.

Remove a now completly invalid check for a maximum virtual
address, the virtual address now ends at 0xFFFFFFFF so
there is no more MAX!! (Thanks David, I completly missed
that one!)

vm_machdep.c
Remove patch kit header and rcsid, fix $Id$.
Now include "npx.h" and use NNPX for controlling the
floating point code.

Replace several 0xFE00000 constants with KERNBASE


# 604 14-Oct-1993 rgrimes

>From David Greenman

Bruce Evans had limited the kernel virtual address space to not include the
last 4MB since it was not being used. Other changes are being made that will
reloate the Alternate Page Directory Table (APDT) into this area so the limit
is being fixed to be the last virtual address. (Infact with this patch you
can now do that relocation)


# 569 10-Oct-1993 rgrimes

Added a compile time #error so that if the user does not specify on of
the proper I_X86CPU in the config file the following error will occur
while building the kernel: (had to line wrap the error for this message)

../../i386/i386/machdep.c:343: #error This kernel is not configured for one \
of the supported CPUs


# 556 08-Oct-1993 rgrimes

All:
removed patch kit headers and sccsids, add $Id$. This is a general
clean up and reallignment with NetBSD-current where possible.

genassym.c:
removed extranious include of reg.h
removed old FP_* defines that have been ifdefed out since the patch kit
removed PCB_SIGC that is not referenced anywhere
add trapframe and sigframe defines
add KERNBASE define for use in locore.s

locore.s:
include npx.h and use NNPX for turning on and off FPU
include machine/cputypes.h for the types of cpu (used in cpu_identify)
change SYSPDREND to be one higher, this is really the base of the
next area, and will be changing again next time I revise the file
Reverse the NOP defines, you now get slow NOP's by default, this
may be what is casuing us trouble with some systems. If you want
the NOPS to be null you now need to have options DUMMY_NOPS.
Now get esym from the boot blocks which don't pass it yet, and
it is not used, but this will be changing.
Move the bit_colors stuff to be in with the rest of Bruces SHOW_A_LOT
things for debugging.
Added NetBSD's CPU type probe code, we now know what type of CPU
we are running on.
Adjust kernel pde calcuation to correct for change in SYSPDREND, no
longer need the +1.

machdep.c
include npx.h and use NNPX for turning on and off FPU
include isa.h, map.h(new file), exec.h in preperation for
changes that are still in process.
Add some of the code for MACHINE_NONCONTIG that will alow us
to better map around the BIOS memory area.
Now print the version, cpu id, real memory and availiable memory
during boot.
Correct the calculation of bufpages, the code was mixing pages
and bytes, it now does the right things. Removed Bill's hack
for limiting the erronous calculation.
add the identifycpu print out code from NetBSD.
remove the definition of the sigframe struct, it belongs in
frame.h
put in printf's about syncing disks on a halt/reboot.
Change the halted message to be a little easier reading.
Clean up of the dump messages, makes the source and the output
much more readable.
Change 0,0 in several places to have spaces after the commas.


# 549 08-Oct-1993 rgrimes

Removed patch kit headers, and rcsid, add $Id$, relocate Terry Lamberts
copyright to match the location that it is in NetBSD.

Remove the __main() {} dummy function, it belongs in kern/init_main.c


# 504 24-Sep-1993 rgrimes

>From: rich@id.slip.bcm.tmc.edu.cdrom.com (Rich Murphey)
Date: Sun, 12 Sep 1993 18:19:05 -0500
This will allow you to compile and run a freebsd kernel with shared
memory support. I haven't tested the shm*() calls yet.

You run out of page table descriptors if you specify 4Mb of sharable
memory (SHMMAXPGS=1024). I don't know what the limit is, but
SHMMAXPGS=64 works. Rich


# 259 09-Aug-1993 rgrimes

From guido@gvr.win.tue.nl Sat Aug 7 06:58:04 1993

I posted some patches on the 386bsd_patchkit list to prohibit io access.
Because of a noninitialised filed in the tss, this was possible.
It is included below as the patch to machdep.c
However, when you do this *necessary* fix (security), it will be
impossible form within user space to do io.

therefor, I included another fix: when you open /dev/io, you
get the access. Of course you can rewrite it to use another minor
and thus giving access to the iospace when /dev/mem is opened, e.g.

NOTE: The /dev/io entry has not been added to /dev/MAKEDEV yet.
The patch is in NetBSD.


# 200 27-Jul-1993 dg

* Applied fixes from Bruce Evans to fix COW bugs, >1MB kernel loading,
profiling, and various protection checks that cause security holes
and system crashes.
* Changed min/max/bcmp/ffs/strlen to be static inline functions
- included from cpufunc.h in via systm.h. This change
improves performance in many parts of the kernel - up to 5% in the
networking layer alone. Note that this requires systm.h to be included
in any file that uses these functions otherwise it won't be able to
find them during the load.
* Fixed incorrect call to splx() in if_is.c
* Fixed bogus variable assignment to splx() in if_ed.c


# 134 16-Jul-1993 dg

New locore from Christoph Rubitschko.


# 132 16-Jul-1993 dg

Updated kernel files to move occurances of "struct args" syscall
argument definitions outside of the function parameter list. This is
to reduce the copious warning messages that (non-Jolitz) gcc produces.
Also fixed some bogus variable declarations and casts to make the
compiler happy.


# 8 18-Jun-1993 paul

Upgrade to GCC 2.X


# 5 12-Jun-1993 rgrimes

This commit was generated by cvs2svn to compensate for changes in r4,
which included commits to RCS files with non-trunk default branches.


# 4 12-Jun-1993 rgrimes

Initial import, 0.1 + pk 0.2.4-B1