MFC r337715, r337751, r337754, r337758, r337813, r338354, r338687,
r339124, r341821:
Add support for boot-time Intel microcode loading.

Merge clang 7.0.1 and several follow-up changes

MFC r318594:

Add libc++experimental.a for std::experimental support

This adds a separate library for supporting std::experimental features.
It is purposefully static, and must be explicitly linked into programs
using -lc++experimental.

PLEASE NOTE: there is NO WARRANTY as to any stability or continuing
existence of the features in the std::experimental parts of the C++
library!

Reviewed by: ed
Differential Revision: https://reviews.freebsd.org/D10840

MFC r318598:

Add PICFLAG to build libc++experimental.a, so it can be used in all
situations.

Noticed by: kib

r336969 | emaste | 2018-07-31 16:12:09 +0200 (Tue, 31 Jul 2018) | 13 lines

llvm: [ELF][ARM] Add Arm ABI names for float ABI ELF Header flags

The ELF for the Arm architecture document defines, for EF_ARM_EABI_VER5
and above, the flags EF_ARM_ABI_FLOAT_HARD and EF_ARM_ABI_FLOAT_SOFT.
These have been defined to be compatible with the existing
EF_ARM_VFP_FLOAT and EF_ARM_SOFT_FLOAT used by gcc for
EF_ARM_EABI_UNKNOWN.

This patch adds the flags in addition to the existing ones so that any
code depending on the old names will still work.

Obtained from: llvm r338370 by Peter Smith

r336970 | emaste | 2018-07-31 16:14:41 +0200 (Tue, 31 Jul 2018) | 9 lines

llvm: [ARM] Complete enumeration values for Tag_ABI_VFP_args

The LLD implementation of Tag_ABI_VFP_args needs to check the rarely
seen values of 3 (toolchain specific) and 4 compatible with both Base
and VFP. Add the missing enumeration values so that LLD can refer to
them without having to use the raw numbers.

Obtained from: llvm r338373 by Peter Smith

r336972 | emaste | 2018-07-31 17:25:03 +0200 (Tue, 31 Jul 2018) | 37 lines

lld: [ELF][ARM] Implement support for Tag_ABI_VFP_args

The Tag_ABI_VFP_args build attribute controls the procedure call
standard used for floating point parameters on ARM. The values are:

0 - Base AAPCS (FP Parameters passed in Core (Integer) registers
1 - VFP AAPCS (FP Parameters passed in FP registers)
2 - Toolchain specific (Neither Base or VFP)
3 - Compatible with all (No use of floating point parameters)

If the Tag_ABI_VFP_args build attribute is missing it has an implicit
value of 0.

We use the attribute in two ways:

* Detect a clash in calling convention between Base, VFP and Toolchain.

we follow ld.bfd's lead and do not error if there is a clash between an
implicit Base AAPCS caused by a missing attribute. Many projects
including the hard-float (VFP AAPCS) version of glibc contain assembler
files that do not use floating point but do not have Tag_ABI_VFP_args.

* Set the EF_ARM_ABI_FLOAT_SOFT or EF_ARM_ABI_FLOAT_HARD ELF header flag

for Base or VFP AAPCS respectively. This flag is used by some ELF
loaders.

References:
* Addenda to, and Errata in, the ABI for the ARM Architecture for
Tag_ABI_VFP_args
* Elf for the ARM Architecture for ELF header flags

Fixes LLVM PR36009

PR: 229050
Obtained from: llvm r338377 by Peter Smith

r337282 | alc | 2018-08-04 04:30:51 +0200 (Sat, 04 Aug 2018) | 7 lines

Set the default image base on arm64 and i386 to a superpage-aligned
address.

Reviewed by: emaste, markj
Discussed with: dim
Differential Revision: https://reviews.freebsd.org/D16385

r339304 | emaste | 2018-10-11 15:19:17 +0200 (Thu, 11 Oct 2018) | 13 lines

lld: set sh_link and sh_info for .rela.plt sections

ELF spec says that for SHT_REL and SHT_RELA sh_link should reference the
associated string table and sh_info should reference the "section to
which the relocation applies." ELF Tool Chain's elfcopy / strip use
this (in part) to control whether or not the relocation entry is copied
to the output.

LLVM PR 37538 https://bugs.llvm.org/show_bug.cgi?id=37538

Approved by: re (kib)
Obtained from: llvm r344226 (backported for 6.0)

MFC r341825:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
the upstream release_70 branch r348686 (effectively, 7.0.1 rc3). The
release will follow very soon, but no more functional changes are
expected.

Release notes for llvm, clang and lld 7.0.0 are available here:
<http://releases.llvm.org/7.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/7.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/7.0.0/tools/lld/docs/ReleaseNotes.html>

PR: 230240, 230355
Relnotes: yes

MFC r342123:

Update clang, llvm, lld, lldb, compiler-rt and libc++ version number to
7.0.1 release r349250. There were no functional changes since the 7.0.1
rc3 import.

PR: 230240, 230355
Relnotes: yes

r343429 | emaste | 2019-01-25 15:46:13 +0100 (Fri, 25 Jan 2019) | 16 lines

clang: default to DWARF 4 as of FreeBSD 13

FreeBSD previously defaulted to DWARF 2 because several tools (gdb,
ctfconvert, etc.) did not support later versions. These have either
been fixed or are deprecated.

Note that gdb 6 still exists but has been moved out of $PATH into
/usr/libexec and is intended only for use by crashinfo(8). The kernel
build sets the DWARF version explicitly via -gdwarf2, so this should
have no effect there.

PR: 234887 [exp-run]
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17930

MFC r343916:

Pull in r352607 from upstream llvm trunk (by Craig Topper):

[X86] Add FPSW as a Def on some FP instructions that were missing it.

Pull in r353141 from upstream llvm trunk (by Craig Topper):

[X86] Connect the default fpsr and dirflag clobbers in inline
assembly to the registers we have defined for them.

Summary:
We don't currently map these constraints to physical register numbers
so they don't make it to the MachineIR representation of inline
assembly.

This could have problems for proper dependency tracking in the
machine schedulers though I don't have a test case that shows that.

Reviewers: rnk

Reviewed By: rnk

Subscribers: eraman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57641

Pull in r353489 from upstream llvm trunk (by Craig Topper):

[X86] Add FPCW as a register and start using it as an implicit use on
floating point instructions.

Summary:
FPCW contains the rounding mode control which we manipulate to
implement fp to integer conversion by changing the roudning mode,
storing the value to the stack, and then changing the rounding mode
back. Because we didn't model FPCW and its dependency chain, other
instructions could be scheduled into the middle of the sequence.

This patch introduces the register and adds it as an implciit def of
FLDCW and implicit use of the FP binary arithmetic instructions and
store instructions. There are more instructions that need to be
updated, but this is a good start. I believe this fixes at least the
reduced test case from PR40529.

Reviewers: RKSimon, spatel, rnk, efriedma, andrew.w.kaylor

Subscribers: dim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57735

These should fix a problem in clang 7.0 where it would sometimes emit
long double floating point instructions in a slightly wrong order,
leading to failures in our libm tests. In particular, the cbrt_test
test case 'cbrtl_powl' and the trig_test test case 'reduction'.

Also bump __FreeBSD_cc_version, to be able to detect this in our test
suite.

Reported by: lwhsu
PR: 234040
Upstream PR: https://bugs.llvm.org/show_bug.cgi?id=40206

MFC r344056:

Pull in r339734 from upstream llvm trunk (by Eli Friedman):

[ARM] Make PerformSHLSimplify add nodes to the DAG worklist correctly.

Intentionally excluding nodes from the DAGCombine worklist is likely
to lead to weird optimizations and infinite loops, so it's generally
a bad idea.

To avoid the infinite loops, fix DAGCombine to use the
isDesirableToCommuteWithShift target hook before performing the
transforms in question, and implement the target hook in the ARM
backend disable the transforms in question.

Fixes https://bugs.llvm.org/show_bug.cgi?id=38530 . (I don't have a
reduced testcase for that bug. But we should have sufficient test
coverage for PerformSHLSimplify given that we're not playing weird
tricks with the worklist. I can try to bugpoint it if necessary,
though.)

Differential Revision: https://reviews.llvm.org/D50667

This should fix a possible hang when compiling sys/dev/nxge/if_nxge.c
(which exists now only in the stable/11 branch) for arm.

MFC r328913:
Move signal trampolines out of locore.s into separate source file.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Give large kernel stack to the initial thread . Otherwise, ZFS
overflows the stack during root mount in some configurations.

Tested by: Fabian Keil <freebsd-listen@fabiankeil.de> (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

Revert bit of the r285627, locore.s does not need include of
opt_kstack_pages.h. The asm gets the right KSTACK_PAGES from the
assym.s.

Reported by: bz
Sponsored by: The FreeBSD Foundation

Fix KSTACK_PAGES issue when the default value was changed in KERNCONF

If KSTACK_PAGES was changed to anything alse than the default,
the value from param.h was taken instead in some places and
the value from KENRCONF in some others. This resulted in
inconsistency which caused corruption in SMP envorinment.

Ensure all places where KSTACK_PAGES are used the opt_kstack_pages.h
is included.

The file opt_kstack_pages.h could not be included in param.h
because was breaking the toolchain compilation.

Reviewed by: kib
Obtained from: Semihalf
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3094

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.

Intel documented that the PAE format for page tables is available
starting with the Pentium Pro, but it is possible that the plain
Pentium CPUs have the required support (Appendix H). The goal is to
enable the option and non-exec mappings on i386 for the GENERIC
kernel. Anybody wanting a useful system on 486, have to reconfigure
the modern i386 kernel anyway.

Discussed with: alc, jhb
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

MFamd64: Add support for extended FPU states on i386. This includes
support for AVX on i386.
- Similar to amd64, move the FPU save area out of the PCB and instead
store saved FPU state in a variable-sized buffer after the PCB on the
stack.
- To support the variable PCB location, alter the locore code to only use
the bottom-most page of proc0stack for init386(). init386() returns
the correct stack pointer to locore which adjusts the stack for thread0
before calling mi_startup().
- Don't bother setting cr3 in thread0's pcb in locore before calling
init386(). It wasn't used (init386() overwrote it at the end) and
it doesn't work with the variable-sized FPU save area.
- Remove the new-bus attachment from npx. This was only ever useful for
external co-processors using IRQ13, but those have not been supported
for several years. npxinit() is now called much earlier during boot
(init386()) similar to amd64.
- Implement PT_{GET,SET}XSTATE and I386_GET_XFPUSTATE.
- npxsave() is now only called from context switch contexts so it can
use XSAVEOPT.

Differential Revision: https://reviews.freebsd.org/D1058
Reviewed by: kib
Tested on: FreeBSD/i386 VM under bhyve on Intel i5-2520

xen: use the same hypercall mechanism for XEN and XENHVM

Currently XEN (PV) and XENHVM (PVHVM) ports use different ways to
issue hypercalls, unify this by filling the hypercall_page under HVM
also.

Approved by: gibbs
Sponsored by: Citrix Systems R&D

amd64/include/xen/hypercall.h:
- Unify Xen hypercall code by always using the PV way.

i386/i386/locore.s:
- Define hypercall_page on i386 XENHVM.

x86/xen/hvm.c:
- Fill hypercall_page on XENHVM kernels using the HVM method (only
when running as an HVM guest).

Simplify the implementation of the identity mapping in start_all_aps().
Since mpboot.s enables processor support for PG_PS before enabling
paging, there is no reason that the identity must use 4 KB page mappings.

Discussed with: jhb

Initialize KPTmap in locore so that vm86.c can call vtophys() (or really
pmap_kextract()) before pmap_bootstrap() is called.

Document the set of pmap functions that may be called before
pmap_bootstrap() is called.

Tested by: bde@
Reviewed by: kib@
Discussed with: jhb@
MFC after: 6 weeks

Simplify pmap_init(). Additionally, correct a harmless misbehavior on i386.
Specifically, where locore had created large page mappings for the kernel,
the wrong vm page array entries were being initialized. The vm page array
entries for the pages containing the kernel were being initialized instead
of the vm page array entries for page table pages.

MFC after: 1 week

Eliminate unused variables (see r137912).

Change some movl's to mov's. Newer GAS no longer accept 'movl' instructions
for moving between a segment register and a 32-bit memory location.

Looked at by: jhb

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).

In order to satisfy ACPI's need for an identity mapping, modify the
temporary mapping created by locore so that the lowest two to four
megabytes can become a permanent identity mapping. This implementation
avoids any use of a large page mapping.

Tweak the comment about mapping a kernel using large pages.

Add the 2nd word of IA32 feature flags. This includes things such as SSE3.

Obtained from: sys/amd64/amd64/identcpu.

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

Reviewed by: arch@

Change the following environment variables to kernel options:

bootp -> BOOTP
bootp.nfsroot -> BOOTP_NFSROOT
bootp.nfsv3 -> BOOTP_NFSV3
bootp.compat -> BOOTP_COMPAT
bootp.wired_to -> BOOTP_WIRED_TO

- i.e. back out the previous commit. It's already possible to
pxeboot(8) with a GENERIC kernel.

Pointed out by: dwmalone

Change the following kernel options to environment variables:

BOOTP -> bootp
BOOTP_NFSROOT -> bootp.nfsroot
BOOTP_NFSV3 -> bootp.nfsv3
BOOTP_COMPAT -> bootp.compat
BOOTP_WIRED_TO -> bootp.wired_to

This lets you PXE boot with a GENERIC kernel by putting this sort of thing
in loader.conf:

bootp="YES"
bootp.nfsroot="YES"
bootp.nfsv3="YES"
bootp.wired_to="bge1"

or even setting the variables manually from the OK prompt.

Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson

New APIC support code:

- The apic interrupt entry points have been rewritten so that each entry
point can serve 32 different vectors. When the entry is executed, it
uses one of the 32-bit ISR registers to determine which vector in its
assigned range was triggered. Thus, the apic code can support 159
different interrupt vectors with only 5 entry points.
- We now always to disable the local APIC to work around an errata in
certain PPros and then re-enable it again if we decide to use the APICs
to route interrupts.
- We no longer map IO APICs or local APICs using special page table
entries. Instead, we just use pmap_mapdev(). We also no longer
export the virtual address of the local APIC as a global symbol to
the rest of the system, but only in local_apic.c. To aid this, the
APIC ID of each CPU is exported as a per-CPU variable.
- Interrupt sources are provided for each intpin on each IO APIC.
Currently, each source is given a unique interrupt vector meaning that
PCI interrupts are not shared on most machines with an I/O APIC.
That mapping for interrupt sources to interrupt vectors is up to the
APIC enumerator driver however.
- We no longer probe to see if we need to use mixed mode to route IRQ 0,
instead we always use mixed mode to route IRQ 0 for now. This can be
disabled via the 'NO_MIXED_MODE' kernel option.
- The npx(4) driver now always probes to see if a built-in FPU is present
since this test can now be performed with the new APIC code. However,
an SMP kernel will panic if there is more than one CPU and a built-in
FPU is not found.
- PCI interrupts are now properly routed when using APICs to route
interrupts, so remove the hack to psuedo-route interrupts when the
intpin register was read.
- The apic.h header was moved to apicreg.h and a new apicvar.h header
that declares the APIs used by the new APIC code was added.

Fix just about as many bugs in my last commit here as there were lines that
I changed. That is never a good sign.
1) only map 1 page at address zero, not 4096 pages
2) page 1 starts at address 4096 (PAGE_SIZE) not 4095 (PAGE_MASK). I
don't even want to think what the pte's looked like.
3) subtract the r/o page group start address from the end before
converting it to a count. Otherwise an extra page is mapped.

If you were affected by this, the symptoms of this was a hang at boot
after the spinner. Sorry folks. :-(

"You broke my laptop!" by: sam

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

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.

Emulate bugs in the old PSE code so that apm works again.

I do not yet understand why, but apm *depended* on the fact that the old
PSE code caused the first 1MB of ram to be mapped read/write because it
was in the same 4MB page as the kernel text+data+bss blob.

If anybody ever tried DISABLE_PSE before, apm would not work.

If your cpu did not have PSE, apm would not work there either (eg: 486).

This bug has been around for a Very Long Time.

The Pentium-4-fix commits did not emulate this unintended side effect of
the PSE post-early-boot fixup, and thus apm blew up. I've added a hack to
emulate the bug until either apm is fixed or we set fire to our bridges.

This is bad though because it gives kernel mode code the opportunity
to accidently write to the first few megs of the general page pool
which is remapped at KERNBASE. It needs to be fixed properly.

Add #include "opt_pmap.h" so locore picks up DISABLE_PSE etc options.

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

Restored clearing of the bss, except for putting it in a correct place
with up to date comments. This fixes booting kernels with boot2
(except for loss of the features provided by loader) and is suitable
for MFC. Contrary to the old comments, most loaders don't clear the bss.
biosboot lost clearing of the bss in a code crunch in 1997, and boot2
never did it.

kan didn't notice the problem with gcc-3.3 putting variables that are
initialized to 0 in the bss until after committing gcc-3.3 because he
was already using essentially this patch. Before gcc-3.3, only the
non-critical `bootdev' variable was clobbered by clearing the bss.

MFC after: 3 days

Don't hide the name of tmpstk, since there is no need to do so and the
HIDENAME() macro seems to be unimplementable in C. (HIDENAME() used
to use invalid token pasting using ## for the STDC case until gcc
started rejecting that; now it uses unportable token pasting using
juxtaposition in all cases.) This reduces use of HIDENAME() in the
kernel to only i386 and amd64 profiling code so that it doesn't bite
most kernels whenever gcc becomes stricter. Problems with HIDENAME()
in userland are smaller because userland mostly doesn't use strict
flags yet. There are some advantages to hiding the name of mcount,
but newer arches shouldn't do it; only amd64 does.

MFC after: 3 days

On second thoughts hide tmpstk better by staticizing it.

Fix the gcc-3.3 boot problem. Gcc now optimizes 'int foo = 0' by moving
it to the bss section and skips the initialization. This causes all
sorts of havoc because the bogus bss zero code clobbered previously set
variables. All our supported boot loaders already zero the bss, even
kgzip for the elf case. Since we dont generate a.out kernels, the old
a.out bootblocks and the a.out kgzip are not a factor anymore.

- Removed APTD and associated macros, it is no longer used.

BANG BANG BANG etc.

Sponsored by: DARPA, Network Associates Laboratories

- 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

Previous commit missed a 1 that should be NGPTD, and an NPDEPG that should
be NPDEPTD. Grumble.

Sponsored by: DARPA, Network Associates Laboratories

- Added macros NPGPTD, NBPTD, and NPDEPTD, for dealing with the size of the
page directory.
- Use these instead of the magic constants 1 or PAGE_SIZE where appropriate.
There are still numerous assumptions that the page directory is exactly
1 page.

Sponsored by: DARPA, Network Associates Laboratories

- Added macros PDESHIFT and PTESHIFT, use these instead of magic constants
in locore.
- Removed the macros PTESIZE and PDESIZE, use sizeof instead in C.

Sponsored by: DARPA, Network Associates Laboratories

Remove BDE_DEBUGGER.

Discussed with: bde

Rename cpuid_cpuinfo to cpu_procinfo. bde requested that I rename this
variable to something in the cpu_* namespace since that's what all the
other cpuid variables were named and cpu_procinfo is what I came up with.

Requested by: bde

Rework part of the previous processor name changes so that we read
cpu_exthigh and cpu_brand in printcpuinfo() instead of in identify_cpu().
We also only do it for known-good values of cpu_vendor which is a bit more
conservative.

Reviewed by: bde (mostly)

- Add a cpu_exthigh variable to hold the highest extended cpuid value
returned from cpuid 0x80000000.
- Add a cpu_brand char array to hold the processor name returned by
cpuid 0x80000002-0x80000004 on AMD, Intel, Transmeta, and possibly
other CPUs.
- Use cpuid to set cpu_exthigh and read the processor name if it is present
in identify_cpu().

Add a cpuid_cpuinfo variable to hold the results of %ebx from cpuid with
%eax of 1 and set it in identify_cpu().

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)

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

Initiate deorbit burn for the i386-only a.out related support. Moves are
under way to move the remnants of the a.out toolchain to ports. As the
comment in src/Makefile said, this stuff is deprecated and one should not
expect this to remain beyond 4.0-REL. It has already lasted WAY beyond
that.

Notable exceptions:
gcc - I have not touched the a.out generation stuff there.
ldd/ldconfig - still have some code to interface with a.out rtld.
old as/ld/etc - I have not removed these yet, pending their move to ports.
some includes - necessary for ldd/ldconfig for now.

Tested on: i386 (extensively), alpha

Revive backed out pmap related changes from Feb 2002. The highlights are:
- It actually works this time, honest!
- Fine grained TLB shootdowns for SMP on i386. IPI's are very expensive,
so try and optimize things where possible.
- Introduce ranged shootdowns that can be done as a single IPI.
- PG_G support for i386
- Specific-cpu targeted shootdowns. For example, there is no sense in
globally purging the TLB cache for where we are stealing a page from
the local unshared process on the local cpu. Use pm_active to track
this.
- Add some instrumentation for the tlb shootdown code.
- Rip out SMP code from <machine/cpufunc.h>
- Try and fix some very bogus PG_G and PG_PS interactions that were bad
enough to cause vm86 bios calls to break. vm86 depended on our existing
bugs and this was the cause of the VESA panics last time.
- Fix the silly one-line error that caused the 'panic: bad pte' last time.
- Fix a couple of other silly one-line errors that should have caused more
pain than they did.

Some more work is needed:
- pmap_{zero,copy}_page[_idle]. These can be done without IPI's if we
have a hook in cpu_switch.
- The IPI handlers need some cleanup. I have a bogus %ds load that can
be avoided.
- APTD handling is rather bogus and appears to be a large source of
global TLB IPI shootdowns for no really good reason.

I see speedups of between 1.5% and ~4% on buildworlds in a while 1 loop.
I expect to see a bigger difference when there is significant pageout
activity or the system otherwise has memory shortages.

I have backed out a few optimizations that I had been using over the last
few days in order to be a little more conservative. I'll revisit these
again over the next few days as the dust settles.

New option: DISABLE_PG_G - In case I missed something.

Consistently line-up /**/ comments so they don't cause line wrappage.

Back out all the pmap related stuff I've touched over the last few days.
There is some unresolved badness that has been eluding me, particularly
affecting uniprocessor kernels. Turning off PG_G helped (which is a bad
sign) but didn't solve it entirely. Userland programs still crashed.

Work-in-progress commit syncing up pmap cleanups that I have been working
on for a while:
- fine grained TLB shootdown for SMP on i386
- ranged TLB shootdowns.. eg: specify a range of pages to shoot down with
a single IPI, since the IPI is very expensive. Adjust some callers
that used to trigger this inside tight loops to do a ranged shootdown
at the end instead.
- PG_G support for SMP on i386 (options ENABLE_PG_G)
- defer PG_G activation till after we decide what we are going to do with
PSE and the 4MB pages at the start of the kernel. This should solve
some rumored strangeness about stale PG_G entries getting stuck
underneath the 4MB pages.
- add some instrumentation for the fine TLB shootdown
- convert some asm instruction wrappers from functions to inlines. gcc
seems to do a fair bit better with this.
- [temporarily!] pessimize the tlb shootdown IPI handlers. I will fix
this again shortly.

This has been working fairly well for me for a while, but I have tweaked
it again prior to commit since my last major testing round. The only
outstanding problem that I know of is PG_G related, which is why there
is an option for it (not on by default for SMP). I have seen a world
speedups by a few percent (as much as 4 or 5% in one case) but I have
*not* accurately measured this - I am a bit sceptical of these numbers.

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.

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

Mostly cosmetic. Move various variables from .s files to .c files so that
gdb generates debug info for them.

There is nothing more embarresing than having three goes at correcting
typos in the same paragraph. s/in in/in/

Submitted by: iedowse

I missed a typo in the last commit: s/whach/which/

Submitted by: bde

s/teh/the/

Add an explanatory note that would have saved me an hour or two
of confusion had it been there when I started reading the code..

Export the actual KERNBASE to the symbol table. We can use nlist() to get
this without having to second guess it in userland.

Move cpu_fxsr definition to C code (so debug info is generated) and where
it is easily #ifdef'ed so that we dont miss unintentional references to it.

Move CR4.PGE enabling code after paging is enabled via CR0.PG based on
the description (2.5. CONTROL REGISTERS) of Intel developer's manual at:
ftp://download.intel.com/design/PentiumII/manuals/24319202.pdf

Reviewed by: peter, bde, tlambert2@mindspring.com
Pointed-out by: "Shin'ya Kumabuchi" <kumabu@t3.rim.or.jp>
MFC after: 1 week

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.

Kill the 4MB kernel limit dead. [I hope :-)].
For UP, we were using $tmp_stk as a stack from the data section. If the
kernel text section grew beyond ~3MB, the data section would be pushed
beyond the temporary 4MB P==V mapping. This would cause the trampoline
up to high memory to fault. The hack workaround I did was to use all of
the page table pages that we already have while preparing the initial
P==V mapping, instead of just the first one.
For SMP, the AP bootstrap process suffered the same sort of problem and
got the same treatment.

MFC candidate - this breaks on 4.x just the same..

Thanks to: Richard Todd <rmtodd@ichotolot.servalan.com>

Make the kernel actually compile and link under a.out, using
gcc -aout -mno-underscores. The bioscall.s tweak is not an a.out
requirement really, but to work around the bugs in the antique version of
gas that used for a.out. Makefile hacks are all that is needed to
get an a.out kernel. There is no telling if it will work though.
This is little more than an academic curiosity anyway since all it is
good for is situations where the boot code is hard wired, eg: rom
bootstraps (such as the gnat box).

GENERIC:
...
size -aout kernel ; chmod 755 kernel
text data bss dec hex
3051520 368640 198688 3618848 373820

Remove the leading underscore from all symbols defined in x86 asm
and used in C or vice versa. The elf compiler uses the same names
for both. Remove asnames.h with great prejudice; it has served its
purpose.

Note that this does not affect the ability to generate an aout kernel
due to gcc's -mno-underscores option.

moral support from: peter, jhb

- Remove compatibility macros for accessing per-cpu variables.
__FreeBSD_version 500015 can be used to detect their disappearance.
- Move the symbols for SMP_prvspace and lapic from globals.s to
locore.s.
- Remove globals.s with extreme prejudice.

Assembler fixes.

Fix opcodes that were typed as ".byte 0xNN, 0xMM" when an older
assembler could not recognise the newer Pentium instructions.
Reviewed by: jhb

Be more careful about cleaning up the stack after function calls early
in the boot. The cleanup must be done in one of the few ways that
db_numargs() understands, so that early backtraces in ddb don't underrun
the stack. The underruns caused reboots a few years ago when there
was an unmapped page above the stack (trapping to abort the command
doesn't work early).

Cleaned up some nearby code.

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

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.

Always include the full symbol table (as specified by its start and
end values in bootinfo) in kernel space if it is loaded (i.e., if its
specified end address is nonzero), not just if it is loaded and DDB
is configured. This may be used to fix kldsym(2) for booting without
/dev/loader; currently, in this case, it just fixes unused pointers
and wastes space consistently. For booting in the normal way with
/boot/loader, the table is included and pointed to in a different way
and kldsym(2) works.

1. `movl' is for use with 32-bit operands. Do NOT use it with 16-bit
operands. `movw' could be used, but instead let the assembler decide
the right instruction to use.
2. AT&T asm syntax requires a leading '*' in front of the operand for
indirect calls and jumps.

PC-98 BIOS copies the DX register into its work area. The value of it
shows `CPUID' and it is useful to identify CPU. So, it is copied from
BIOS work area to the cpu_id variable (PC-98 only).

Submitted by: chi@bd.mbn.or.jp (Chiharu Shibata)

The address 0x472 is used for the SCSI HDD geometry information on
PC-98. Therefore, the PC-98 kernel should not modify it.

oszsigcode -> szosigcode

Pointed out by: bde

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

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

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.

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

$Id$ -> $FreeBSD$

Remove some droppings left over from the removal of the APM hooks.

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>

Unifdef VM86.

Reviewed by: silence on on -current

s/main/mi_startup/ for the kernel entry point so that egcs doesn't get
upset about it (and generate things like __main() calls that are reserved
for main()). Renaming was phk's suggestion, but I'd already thought about
it too. (phk liked my suggested name tada() but I decided against it :-)

Reviewed by: phk

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>

Use offset to _pc98_system_parameter instead of immediate value which
assumes KERNBASE=0x100000.

Moved pc98_system_parameter from .text to .data to make ELF kernel
work.

Use CNAME macro for pc98_system_parameter, which is referenced from C
source.

Submitted by: Masanori Kanaoka <kana@saijo.mke.mei.co.jp>

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.

mp_machdep.c: Set a vector to boot code (PC-98).
locore.s: Tell the bios to warmboot next time (PC-98).

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.

Fix up the kernel environment and module data pointers in the bootinfo if
they are present.
If we are told where the end of the loaded kernel image is, believe it.

Use correct virtual address when configuring the per CPU idle page directory
for a vm86 call under SMP.

Copy in the nfs_diskless structure if NFS_ROOT is defined. A previous
change to include nfs_root.h precluded NFS from being defined.
Submitted by: Parag Patel <parag@cgt.com>

Re-arrange the page layout used by vm86_bioscall so that we can
potentially re-use the stack page.

Cosmetic cleanup of the code to de-obfuscate it and make it easier
to follow. There should be no functional changes in this commit.

convert some nfs tunables to options, these are:
NFS_MINATTRTIMO VREG attrib cache timeout in sec
NFS_MAXATTRTIMO
NFS_MINDIRATTRTIMO VDIR attrib cache timeout in sec
NFS_MAXDIRATTRTIMO
NFS_GATHERDELAY Default write gather delay (msec)
NFS_UIDHASHSIZ Tune the size of nfssvc_sock with this
NFS_WDELAYHASHSIZ and with this
NFS_MUIDHASHSIZ Tune the size of nfsmount with this
NFS_NOSERVER (already documented in LINT)
NFS_DEBUG turn on NFS debugging

also, because NFS_ROOT is used by very different files, it has been
renamed to opt_nfsroot.h instead of the old opt_nfs.h....

Removed unused includes.

If vm86 services are available, use these to perform the APM BIOS
probe and intialisation. This will ultimately remove the grubby (but
functional) hack that copies a real-mode function into low memory
early in locore.s.

Rather than filling this file up with SMP .sets, use those from
globals.s instead.
Initialize curproc in the same place for both UP and SMP.

Time changes mark 2:

* Figure out UTC relative to boottime. Four new functions provide
time relative to boottime.

* move "runtime" into struct proc. This helps fix the calcru()
problem in SMP.

* kill mono_time.

* add timespec{add|sub|cmp} macros to time.h. (XXX: These may change!)

* nanosleep, select & poll takes long sleeps one day at a time

Reviewed by: bde
Tested by: ache and others

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.

Include "opt_nfs.h"

Pointed out by: Eric L. Hernes <erich@lodgenet.com>

Make the BOOTP family new-style options (in opt_bootp.h)

Use UPAGES when setting up private pages for SMP (which includes idle stack).

Use same address for USERCONFIG_BOOT on PC-98 as IBM-PC.

Submitted by: H. Nokubi <h-nokubi@nmit.tmg.nec.co.jp>
Forgotten by: kato

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.

Implement the parts needed for VM86 under SMP.

Add support for more than 1 page of idle process stack on SMP systems.

General cleanup of the lock pushdown code. They are grouped and enabled
from machine/smptests.h:

#define PUSHDOWN_LEVEL_1
#define PUSHDOWN_LEVEL_2
#define PUSHDOWN_LEVEL_3
#define PUSHDOWN_LEVEL_4_NOT

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.

The last of the encapsolation of cpl/spl/ipending things into a critical
region protected by the simplelock 'cpl_lock'.

Notes:

- this code is currently controlled on a section by section basis with
defines in machine/param.h. All sections are currently enabled.

- this code is not as clean as I would like, but that can wait till later.

- the "giant lock" still surrounds most instances of this "cpl region".
I still have to do the code that arbitrates setting cpl between the
top and bottom halves of the kernel.

- the possibility of deadlock exists, I am committing the code at this
point so as to exercise it and detect any such cases B4 the "giant lock"
is removed.

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>

Removed unused #includes.

Hopefully fix a few problems that could cause hangs in SMP mode.
1) Make sure that the region mapped by a 4MB page is
properly aligned.
2) Don't turn on the PG_G flag in locore for SMP. I plan
to do that later in startup anyway.
3) Make sure the 2nd processor has PSE enabled, so that 4MB
pages don't hose it.

We don't use PG_G yet on SMP -- there is work to be done to make that
work correctly. It isn't that important anyway...

Oops, added popfl after trynexgen label.

PR: 4091
Submitted by: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp>

Added other_cpus to CPU private page.

This variable is a bitmap showing all CPUs present EXCEPT the CPU
owning the variable. In other words, it is equal to the global bitmap
'all_cpus' minus its own bit.

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

remove no longer needed opt_smp.h includes

Ignore the supplied nfs_diskless structure from the bootstrap loader
if we want to use NFS v3 to mount root and swap.

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!

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.

Clean up some dead wood. Kill the page table page for mapping the
proc0/idlePTD/bootstrap stack into place in user space. We save 4K.
Remove p0upa, it is now unneeded.

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.

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>

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Removed PG_N from here, too. Some machines don't like it and it's unnecessary.

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.

Change this back to movl for -current since it seems to work there.
Bruce says that movl is broken in -stable, which would certainly explain
why this didn't work there.

movl instruction should have been lea (this is why userconfig didn't
work in 2.1).

Spotted-by-the-keen-eyes-of: Don Lewis <Don.Lewis@tsc.tdk.com>

Support the PG_G flag on Pentium-Pro processors. This pretty
much eliminates the unnecessary unmapping of the kernel during
context switches and during invtlb...

Put I*86_CPU defines in opt_cpu.h.

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

Renamed upa to p0upa to match p0upt.

Cleaned up some comments.

Cleanup the last of the assembly time "-KERNBASE" relocations.

Fix brino on my part. _etext doesn't include the padding to a page
boundary, which means that it doesn't mark the start of the data
section (which is then inaccessible to the programmer ??).
Hopefully fixes recent locore reboot problems.

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... :-)

removed:
CLBYTES PD_SHIFT PGSHIFT NBPG PGOFSET CLSIZELOG2 CLSIZE pdei()
ptei() kvtopte() ptetov() ispt() ptetoav() &c &c
new:
NPDEPG

Major macro cleanup.

Remove a spurious mapping that was introduced earlier.

Fix some bugs I introduced and some old ones as well.
Add BDE_DEBUGGER back.
Improve quality of comments.
Thanks Bruce!

Reviewed by: phk
Submitted by: bde

Fixed a bug introoduced in the previous change. ISA device memory was
mapped to semi-random place(s) depending on the content(s) of physical
address 0xA0000. This was fatal at least on my system with a some
memory-mapped devices. Console syscons somehow wasn't affected. It
bogusly hardcodes the address. Sigh.

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.

Removed vestiges of dummy frame at top of tmpstk.

Use alignment macros where appropriate.

Cleaned up #includes.

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.

Rewrote cpu_fork so that it doesn't use pmap_activate, and removed
pmap_activate since it's not used anymore. Changed cpu_fork so that
it uses one line of inline assembly rather than calling mvesp() to
get the current stack pointer. Removed mvesp() since it is no longer
being used.

Increase tmpstk size to 8K and make certain it is longword aligned.

Convert DDB to new-style option.

Fix one more label that I overlooked with the P6 support. Sigh.

Fix a lable goofup I made in the previous P6 support changes.

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.

Our existing Cyrix cache-disable code was short-cutting the steps for
setting the control register. Make the read and write operations two
completely separate steps.

While we're at it, pull in the whole set of Cyrix cache control options
from NetBSD-current, since a few motherboards do the right thing with
the Cyrix chip.

There is no option to disable the internal cache completely (yet).

Reviewed by: pst
Obtained from: NetBSD

1) Don't double map the kernel page tables. The double mapping was never
used and went a long way toward confusing the code.
2) Fix proc0's initial stack to not be 48 bytes smaller than it needs to
be.
3) Correct comment about 'first' arg to init386().

Remove relocation of Crtat. Drivers already relocate it (somewhat
bogusly). We used to undo the driver relocation here before doing
a somewhat less bogus relocation. The result was a null relocation
here.

Make path to kernel absolute if it is passed in relative. This fixes
a related bug in some of the new 'foo'boot bootstrap code that has been
added over the past months. This change makes it no longer necessary
for the bootstrap to fix up the path (i.e. it can be removed).

Remove gratuitous waste of 2K of memory for BIOS variables. We never load
the kernel at 0-640k; we haven't had the ability to do that since before
2.0R. Furthermore, I fail to see how putting an instruction at 0 and then
doing a .org 0x500 is going to prevent the stuff from getting clobbered
in the first place; a.out is just too stupid to know about sparse address
spaces.

Moved bb stuff to support.s per Bruces suggestion.

Add a dummy ___bb_init_func for BB profiling of the kernel.
To use this: recompile src/gnu/usr.bin/cc, compile your kernel. The
files you want to profile should be compiled with '-a -g'. "strip -x"
the kernel and run. You don't need to profile all files in the kernel.
My next commit is the program to extract the data from the running kernel.

This is the latest version of the APM stuff from HOSOKAWA, I have looked
briefly over it, and see some serious architectural issues in this stuff.

On the other hand, I doubt that we will have any solution to these issues
before 2.1, so we might as well leave this in.

Most of the stuff is bracketed by #ifdef's so it shouldn't matter too much
in the normal case.

Reviewed by: phk
Submitted by: HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>

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 ?

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.

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.

Grap the bootinfo structure the bootblock passes us.

Initialize %fs and %gs from %ds.
This seems to stabilize the APM-bios on my Gateway Handbook, and it makes
sense in general too.

Added hooks for an easy drop-in of the pcvt concole driver.
Don't panic:-), this is simple stuff just doing exactly the same as for syscons.
(files.i386 did already contain the necessary stuff.)

locore.s:
Build a dummy frame at the top of tmpstk to help debuggers trace the stack
when the system is idle.

swtch.s: idle():
Initialize the frame pointer so that debuggers don't try to trace a bogus
stack.

Load the frame pointer, load the stack pointer and switch out the old
stack in the unique order that never leaves one of the pointers pointers
invalid so that debuggers can trace idle(). Disabling interrupts
provides sufficient validity for normal operation, but debuggers use
(trace) traps.

Move definition and initialization of video_mode_pointer to syscons.c.

Use the correct macro for deciding whether syscons' variables should
be accessed.

Remove some unused declarations and document a bogus one.

Moved initialization of tmpstk so that it immediately follows the kernel
text. Fixed rounding bug that caused the last page of kernel text to be
read/write instead of read-only. This is important now that tmpstk can
crash into it. Removed +4 bias of tmpstk because it screws up ddb's
ability to traceback correctly.

Autoconf is the one to realize that we are booted disk-less and start the
ball rolling. locore is just moving some data from the boot-program.

Peter Dufaults comconsole changes.

Submitted by: Peter Dufault

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.

Correct #ifdef for nfs_disless support is #ifdef NFS, there will be no
option DISKLESS for the 2.0 nfs diskless support. A 2.0 diskless kernel
simple needs NFS linked in statically.

#ifdef DISKLESS the copying of the nfs_diskless structure. Not the best
solution, but the only one I have time for at the moment.

1. Eliminate unused esym global from locore, our boot code never supported
that and when it does it will be done differently.

2. The kernel now does a frame setup on entry so it ``looks'' like a
real function call. This will be needed by future boot code and
debuggers.

3. Clean up stack offsets to all be in decimal and use %ebp when copying
parameters in from the boot code.

4. Implement version 1 of the uniform boot code passing mechanism with
support for kernelname passing and nfs_diskless structure passing.

5. Document the 3 different ways the kernel is called depending on what code
is calling it.

Patch from HOSOKAWA Tatsumi to fix bug in the size of apm_current_gdt_pdesc

Submitted by: HOSOKAWA Tatsumi

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

Laptop Advanced Power Management support by HOSOKAWA Tatsumi.

Submitted by: HOSOKAWA Tatsumi

Make Cyrix CPU flush internal cache any time it goes into hold state.
(Meant to commit this a long time ago... oh well).

Added support for many more videomodes, including graphic modes up til
320x200 256col VGA. This is nessesary for the iBCS stuff to work right.
(And we get the benefit of more video modes). Uses the videocard BIOS
to optain mode tables.
Added a "green" saver, switches off the syncs for "green" monitors.

Reviewed by:
Submitted by:
Obtained from:

Eliminated a whole pile of ancient (we're taking 4.3BSD) VM system
related #define constants. Corrected incorrect VM_MAX_KERNEL_ADDRESS.

Reviewed by: John Dyson

Fix comments.

DOn't allow I/O register access in process 1 (oops).

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

Initialize eflags register - brought over from 1.1.5.

It's not necessary to make page tables write-through, so get rid of this
(this was an experimental change which probably shouldn't have been
committed). I/O pages are still marked non-cacheable, however.

Pad `_cpu_vendor' to finish on a 32-bit boundary so that most of the
locore globals aren't misaligned.

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

Add back in CPU detection copde from 1.1.5. As an added bonus, the
hw.model MIB variable is now declared correctly.

Added some missing cld's (OOPS!) and changed the position of some of
the others to make them easier to spot.

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman

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.

Removed all uses of "USE_486_WRITE_PROTECT" and made this automatic.
Reordered and removed some NOP's.

Make I/O memory explicitly non-cacheable. This is purely an asthetic
change.

NFS Diskless booting support added.

"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).

Add _bde_exists: label so that the global is really defined. Fix spelling
error (mount -> amount)

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.

Made all header files idempotent and moved incorrect common data from
headers into a related source file. (This is the only change to locore.s).
Also fixed pg() to be properly declared and use stdargs.

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

Removed hack that did the R_SHIFT of unsigned numbers, no longer need
to do this as I have changed to using PDTI's as the bases for the vm
system layout.

Eliminate constants SYSPDROFF and SYSPDREND, now use NKPTE to control the size
of the kernel virtual space.

Eliminate constant PDRPDROFF, now use PDTDTPI to control location of PTD,
PTDmap and PTDpde

Eliminate constant APDRPDROFF, now use APTDPTDI to control location of APTD,
APTDmap and APTDpde.

Still need to fix Sysmap location (it is still a constant).

.globl statements are now consistent with respect to <comma><space>, the
<space> being removed from all .globl statements.

Document the fillkpt macro as to what registers control what.

Fix some comments that went past column 80, and clean/line some others up.

Remove constand for _Crtat, now use KERNBASE+constant, this still needs work.

Replace constants for offsets of sigcode parameters with symbolic names
from assym.s

Mark the sigreturn() call with XXX since we use the hardcoded constant
for the system call number, this is bogus and should be a #define or
something some place!

The kernel before and after this change was verified with cmp, not one
byte changed. These are all cosmetic clean up changes that makes the
code more correct and easier to move the kernels virtual address space
and size.

SYSPDROFF and SYSPDREND are now calculated using KERNBASE, KERNSIZE and
PDRSHIFT.

The SYSTEM constant that was defined in this file has been replaced
with KERNBASE from param.h.

Changed almost all # style comments to /* */ C style comments. Several
comments cleaned up so that they make a little more since.

In the comments that describe C calling conventions to assembler routines
used a comma space sequence to seperate arguments and removed the space
between the function name and the argument list.

Removed useless comments like /* clr eax */.

Changed all comma space sequences on assemble instructions to just be comma.

Removed spaces after $ operators to make the file consistent, this may need
to change again (ie: $KERNBASE should probably be $(KERNBASE), but for now
it all seems to work just fine.) This may become a problem with the C
pre-processor.

Changed several double blank lines to single blank lines that where used
to seperate the I/O routines, these routines are blocked enough that we
don't need double blank lines between them.

Changed sequence of I/O routines to be all input functions, all output
functions instead of just the opposite.

Moved the SHOW_A_LOT debug stuff to near the end of the file.

Changed two occurances of the constant 0xfff to NBPG-1.

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.

Add symbolic name for system page directory end, and change constant to
a calculation for the system page directory tables.

* 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

New locore from Christoph Rubitschko.

This commit was generated by cvs2svn to compensate for changes in r4,
which included commits to RCS files with non-trunk default branches.

Initial import, 0.1 + pk 0.2.4-B1