ddb: Use bool for boolean variables in MD code

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D43695

Stop using expressions in _Alignof()

_Alignof(expression) is a non-standard extension. This is not allowed
in gnu11 and gnu17 which follow the C11 standard _Alignof(type).

Reviewed by: arichardson, imp, jhb
Fixes: 4a9cd9fc22d7 amd64 db_trace: Reject unaligned frame pointers
Fixes: 7ccaf76a27f1 riscv db_trace: Ensure trapframe pointer is suitably aligned.
Fixes: 638c68897fbd arm64 db_trace: Ensure trapframe pointer is suitably aligned.
Differential Revision: https://reviews.freebsd.org/D43409

sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

amd64 db_trace: Reject unaligned frame pointers

Switch to using db_addr_t to hold frame pointer values until they are
verified to be suitably aligned.

Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D41532

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

ddb: print the actual syscall name

Some architectures will pretty-print a system call trap in the
backtrace. Rather than printing the symbol, use the syscallname()
function to pull the string from the sv_syscallnames array corresponding
to the process. This simplifies the function somewhat.

Mostly, this will result in dropping the "sys" prefix, e.g. "sys_exit"
will now be printed simply as "exit".

Make two minor tweaks to the function signature: use a u_int for the
syscall number since this is a more correct type (see the 'code' member
of struct syscall_args), and make the thread pointer the first argument.
The latter is more natural and conventional.

Suggested by: jrtc27
Reviewed by: jrtc27, markj, jhb
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D37200

amd64/db_trace.c: remove stray prototype

Sponsored by: NVIDIA networking
MFC after: 1 week

ddb: de-duplicate decode_syscall()

Only i386 and amd64 print the decoded syscall name in the backtrace.
This de-duplication facilitates further changes and adoption by other
platforms.

Reviewed by: jrtc27, markj, jhb
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D36565

Create sys/reg.h for the common code previously in machine/reg.h

Move the common kernel function signatures from machine/reg.h to a new
sys/reg.h. This is in preperation for adding PT_GETREGSET to ptrace(2).

Reviewed by: imp, markj
Sponsored by: DARPA, AFRL (original work)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19830

Annotate amd64 stack unwinders with __nomemorysanitize

Sponsored by: The FreeBSD Foundation

ddb: replace watchpoint set/clear functions

Use the new kdb variants. Print more specific error messages.

Reviewed by: jhb, markj
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D29156

x86: implement kdb watchpoint functions

Add wrappers around the dbreg interface that can be consumed by MI
kernel debugger code. The dbreg functions themselves are updated to
return error codes, not just -1. dbreg_set_watchpoint() is extended to
accept access bits as an argument.

Reviewed by: jhb, kib, markj
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D29155

x86: consolidate hw watchpoint logic into new file

This is a prerequisite to using these functions outside of ddb, but also
provides some cleanup and minor refactoring. This code is almost
entirely duplicated between the two implementations, the only
significant difference being the lack of dbreg synchronization on i386.

Cleanups are:
- demote some internal functions to static
- use the constant NDBREGS instead of a '4' literal
- remove K&R definitions
- some added comments

Reviewed by: kib, jhb
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29153

amd64: clean up empty lines in .c and .h files

teach db_nextframe/x86 about [X]xen_intr_upcall interrupt handler

Discussed with: kib, royger
MFC after: 3 weeks
Sponsored by: Panzura

db_nextframe/amd64: remove TRAP_INTERRUPT frame type

Besides the confusing name, this type is effectively unused.
In all cases where it could be set, the INTERRUPT type is set by the
earlier code. The conditions for TRAP_INTERRUPT are a subset of the
conditions for INTERRUPT.

Reviewed by: kib, markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D22305

Move most of the contents of opt_compat.h to opt_global.h.

opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.

Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.

Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.

Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941

db_nextframe/amd64: catch up with r328083 to recognize fast_syscall_common

Since that change the system call stack traces look like this:
...
sys___sysctl() at sys___sysctl+0x5f/frame 0xfffffe0028e13ac0
amd64_syscall() at amd64_syscall+0x79b/frame 0xfffffe0028e13bf0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0028e13bf0
So, db_nextframe() stopped recognizing the system call frame.
This commit should fix that.

Reviewed by: kib
MFC after: 4 days

Ensure 'name' is not NULL before passing to strcmp().

This avoids a nested page fault when obtaining a stack trace in DDB if
the address from the first frame does not resolve to a known symbol.

MFC after: 1 week
Sponsored by: Chelsio Communications

Use a dedicated per-CPU stack for machine check exceptions.

Similar to NMIs, machine check exceptions can fire at any time and are
not masked by IF. This means that machine checks can fire when the
kstack is too deep to hold a trap frame, or at critical sections in
trap handlers when a user %gs is used with a kernel %cs. Use the same
strategy used for NMIs of using a dedicated per-CPU stack configured
in IST 3. Store the CPU's pcpu pointer at the stop of the stack so
that the machine check handler can reliably find the proper value for
%gs (also borrowed from NMIs).

This should also fix a similar issue with PTI with a MC# occurring
while the CPU is executing on the trampoline stack.

While here, bypass trap() entirely and just call mca_intr(). This
avoids a bogus call to kdb_reenter() (there's no reason to try to
reenter kdb if a MC# is raised).

Reviewed by: kib
Tested by: avg (on AMD without PTI)
Differential Revision: https://reviews.freebsd.org/D13962

Don't access the reserved registers %dr4 and %dr5 on i386.

On the original i386, %dr[4-5] were unimplemented but not very clearly
reserved, so debuggers read them to print them. i386 was still doing
this.

On the original athlon64, %dr[4-5] are documented as reserved but are
aliased to %dr[6-7] unless CR4_DE is set, when accessing them traps.

On 2 of my systems, accessing %dr[4-5] trapped sometimes. On my Haswell
system, the apparent randomness was because the boot CPU starts with
CR4_DE set while all other CPUs start with CR4_DE clear. FreeBSD
doesn't support the data breakpoints enabled by CR4_DE and it never
changes this flag, so the flag remains different across CPUs and
the behaviour seemed inconsistent except while booting when the CPU
doesn't change.

The invalid accesses broke:
- read access for printing the registers in ddb "show watches" on CPUs
with CR4_DE set
- read accesses in fill_dbregs() on CPUs with CR4_DE set. This didn't
implement panic(3) since the user case always skipped %dr[4-5].
- write accesses in set_dbregs(). This also didn't affect userland.
When it didn't trap, the aliasing made it fragile.

Don't print the dummy (zero) values of %dr[4-5] in "show watches" for
i386 or amd64. Fix style bugs near this printing.

amd64 also has space in the dbregs struct for the reserved %dr[8-15]
and already didn't print the dummy values for these, and never accessed
any of the 10 reserved debug registers.

Remove cpufuncs for making the invalid accesses. Even amd64 had these.

Revert crap accidentally committed

Revert r312923 a better approach will be taken later

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

Differential Revision: https://reviews.freebsd.org/D2784
Reviewed by: kib, markj
MFC after: 2 weeks

Let the unwinder handle faults during function prologues or epilogues.

The i386 and amd64 DDB stack unwinders contain code to detect and handle
the case where the first frame is not completely set up or torn down. This
code was accidentally unused however, since db_backtrace() was never called
with a non-NULL trap frame. This change fixes that.

Also remove get_rsp() from the amd64 code. It appears to have come from
i386, which needs to take into account whether the exception triggered a
CPL switch, since SS:ESP is only pushed onto the stack if so. On amd64,
SS:RSP is pushed regardless, so get_rsp() was doing the wrong thing for
kernel-mode exceptions. As a result, we can also remove custom print
functions for these registers.

Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D2881

Improve stack unwinding on i386 and amd64 after an IP fault.

If we can't find a symbol corresponding to the faulting instruction, assume
that the previously-executed function is a call and attempt to find the
calling function using the return address on the stack. Otherwise we end
up associating the last stack frame with the current call, which is
incorrect and causes the unwinder to skip printing of the calling function,
resulting in a confusing backtrace.

Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D2859

Remove some dead code from DDB's amd64 stack unwinder.

The amd64 port copied some code from i386 to fetch function arguments and
display them in backtraces. However, it was commented out and can't easily
be implemented since the function arguments are passed in
registers rather than on the stack in amd64. Remove it in preparation for
some bug fixes in this area.

Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D2857

Fix the hardware watchpoints on SMP amd64. Load the updated %dr
registers also on other CPUs, besides the CPU which happens to execute
the ddb. The debugging registers are stored in the pcpu area,
together with the command which is executed by the IPI stop handler
upon resume.

Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Print the frame addresses for the backtraces on i386 and amd64. It
allows both to inspect the frame sizes and to manually peek into the
frames from ddb, if needed.

Reviewed by: dim
MFC after: 2 weeks

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

MFC r205014,205015:

Provide groundwork for 32-bit binary compatibility on non-x86 platforms,
for upcoming 64-bit PowerPC and MIPS support. This renames the COMPAT_IA32
option to COMPAT_FREEBSD32, removes some IA32-specific code from MI parts
of the kernel and enhances the freebsd32 compatibility code to support
big-endian platforms.

This MFC is required for MFCs of later changes to the freebsd32
compatibility from HEAD.

Requested by: kib

Provide groundwork for 32-bit binary compatibility on non-x86 platforms,
for upcoming 64-bit PowerPC and MIPS support. This renames the COMPAT_IA32
option to COMPAT_FREEBSD32, removes some IA32-specific code from MI parts
of the kernel and enhances the freebsd32 compatibility code to support
big-endian platforms.

Reviewed by: kib, jhb

Save and restore segment registers on amd64 when entering and leaving
the kernel on amd64. Fill and read segment registers for mcontext and
signals. Handle traps caused by restoration of the
invalidated selectors.

Implement user-mode creation and manipulation of the process-specific
LDT descriptors for amd64, see sysarch(2).

Implement support for TSS i/o port access permission bitmap for amd64.

Context-switch LDT and TSS. Do not save and restore segment registers on
the context switch, that is handled by kernel enter/leave trampolines
now. Remove segment restore code from the signal trampolines for
freebsd/amd64, freebsd/ia32 and linux/i386 for the same reason.

Implement amd64-specific compat shims for sysarch.

Linuxolator (temporary ?) switched to use gsbase for thread_area pointer.

TODO:
Currently, gdb is not adapted to show segment registers from struct reg.
Also, no machine-depended ptrace command is added to set segment
registers for debugged process.

In collaboration with: pho
Discussed with: peter
Reviewed by: jhb
Linuxolator tested by: dchagin

Initial suspend/resume support for amd64.

This code is heavily inspired by Takanori Watanabe's experimental SMP patch
for i386 and large portion was shamelessly cut and pasted from Peter Wemm's
AP boot code.

Improve db_backtrace() for compat ia32 on amd64. 32bit image enters
the kernel via Xint0x80_syscall().

Submitted by: dchagin
MFC after: 1 week

- Import the HEAD csup code which is the basis for the cvsmode work.

Break out stack(9) from ddb(4):

- Introduce per-architecture stack_machdep.c to hold stack_save(9).
- Introduce per-architecture machine/stack.h to capture any common
definitions required between db_trace.c and stack_machdep.c.
- Add new kernel option "options STACK"; we will build in stack(9) if it is
defined, or also if "options DDB" is defined to provide compatibility
with existing users of stack(9).

Add new stack_save_td(9) function, which allows the capture of a stacktrace
of another thread rather than the current thread, which the existing
stack_save(9) was limited to. It requires that the thread be neither
swapped out nor running, which is the responsibility of the consumer to
enforce.

Update stack(9) man page.

Build tested: amd64, arm, i386, ia64, powerpc, sparc64, sun4v
Runtime tested: amd64 (rwatson), arm (cognet), i386 (rwatson)

Add support for cross double fault frames in stack traces:
- Populate the register values for the trapframe put on the stack by the
double fault handler.
- Teach DDB's trace routine to treat a double fault like other trap frames.

MFC after: 3 days

Add support for 8 byte hardware watches in long mode. Kernel hardware
watches support 8 byte watches. For userland, we disallow 8 byte watches
for 32-bit tasks.

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

A few more style fixes.

Various whitespace and style fixes.

Don't show debug registers in "show registers". Special registers should
be displayed specially, and debug registers are among of the least
interesting special registers (far behind %cr3). The debug registers
are still accessible as variables and displayed in another bogus place
("show watches").

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

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

MFi386: add a TRAP_INTERRUPT case

Fix watch address truncation. The address was truncated when it was passed to
amd64_set_watch() as 'unsigned int' and 'unsigned int' is 32bit long on amd64.

Even with that fix hardware watchpoint don't work for me on amd64, ie. when
I set the watchpoint and write a byte there, nothing happens.

- Improve the INKERNEL macro such that it can no longer give false positives.
This fixes the stack(9) functionality.

Submitted by: Antoine Brodin <antoine.brodin@laposte.net>

MFi386:
- Move PUSH_FRAME and POP_FRAME to asmacros.h and use PUSH_FRAME in
atpic entry points.
- Move PCPU_* asm macros out of the middle of the asm profiling macros.
- Pass IRQ vector argument as an int rather than void * to reduce diffs
with i386.
- EOI the lapic in C for the lapic timer handler.
- GC unused Xcpuast function.
- Split IPI_STOP handling code of ipi_nmi_handler() out into a
cpustop_handler() function and call it from Xcpustop rather than
duplicating all the logic in assembly.
- Fixup the list of symbols with interrupt frames in ddb traces.
Xatpic_fastintr* have never existed on amd64, and the lapic timer
handler and various IPI handlers were missing.
- Use trapframe instead of intrframe for interrupt entry points (on amd64
the interrupt vector was already a separate argument, so the two frames
were already identical) and GC intrframe.

Submitted by: peter (3)

Move the prototypes of db_md_set_watchpoint(), db_md_clr_watchpoint()
and db_md_list_watchpoints() to ddb/ddb.h.

- Special-case NMI handling on the AMD64.

On entry or exit from the kernel the 'alltraps' and 'doreti' code
used taken by normal traps disables interrupts to protect the
critical sections where it is setting up %gs.

This protection is insufficient in the presence of NMIs since NMIs
can be taken even when the processor has disabled normal interrupts.
Thus the NMI handler needs to actually read MSR_GBASE on entry to
the kernel to determine whether a swap of %gs using 'swapgs' is
needed. However, reads of MSRs are expensive and integrating this
check into the 'alltraps'/'doreti' path would penalize normal
interrupts.

- Teach DDB about the 'nmi_calltrap' symbol.

Reviewed by: bde, peter (older versions of this change)

- Add support for saving stack traces and displaying them via printf(9)
and KTR.

Contributed by: Antoine Brodin <antoine.brodin@laposte.net>
Concept code from: Neal Fachan <neal@isilon.com>

- Improve the definition of INKERNEL() to include the DMAP area and the
proper start of the kernel area.

Discussed with: peter

MFi386: use %rip - 1 for the symbol search address (for noreturn funcs)

Begin all license/copyright comments with /*-

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

MFC after: 1 month
Inspired by: kris

- Add support for "paging" in stack trace output. That is, when you do
a stack trace from ddb, the output will pause with a '--More--' prompt
every 18 lines. If you hit Enter, it will print another line and prompt
again. If you hit space it will output another page and then prompt.
If you hit 'q' or 'x' it will abort the rest of the stack trace.
- Fix the sparc64 userland stack trace to honor the total count of lines
to print. This is useful if your trace happens to walk back onto
0xdeadc0de and gets stuck in an endless loop.

MFC after: 1 month
Tested on: i386, alpha, sparc64

Unify db_stack_trace_cmd(). All it did was look up the thread given
the thread ID and call db_trace_thread().
Since arm has all the logic in db_stack_trace_cmd(), rename the
new DB_COMMAND function to db_stack_trace to avoid conflicts on
arm.
While here, have db_stack_trace parse its own arguments so that
we can use a more natural radix for IDs. If the ID is not a thread
ID, or more precisely when no thread exists with the ID, try if
there's a process with that ID and return the first thread in it.
This makes it easier to print stack traces from the ps output.

requested by: rwatson@
tested on: amd64, i386, ia64

Mega update for the KDB framework: turn DDB into a KDB backend.
Most of the changes are a direct result of adding thread awareness.
Typically, DDB_REGS is gone. All registers are taken from the
trapframe and backtraces use the PCB based contexts. DDB_REGS was
defined to be a trapframe on all platforms anyway.
Thread awareness introduces the following new commands:
thread X switch to thread X (where X is the TID),
show threads list all threads.

The backtrace code has been made more flexible so that one can
create backtraces for any thread by giving the thread ID as an
argument to trace.

With this change, ia64 has support for breakpoints.

Un-stub the hardware debug register stuff.

Initial landing of SMP support for FreeBSD/amd64.

- This is heavily derived from John Baldwin's apic/pci cleanup on i386.
- I have completely rewritten or drastically cleaned up some other parts.
(in particular, bootstrap)
- This is still a WIP. It seems that there are some highly bogus bioses
on nVidia nForce3-150 boards. I can't stress how broken these boards
are. I have a workaround in mind, but right now the Asus SK8N is broken.
The Gigabyte K8NPro (nVidia based) is also mind-numbingly hosed.
- Most of my testing has been with SCHED_ULE. SCHED_4BSD works.
- the apic and acpi components are 'standard'.
- If you have an nVidia nForce3-150 board, you are stuck with 'device
atpic' in addition, because they somehow managed to forget to connect the
8254 timer to the apic, even though its in the same silicon! ARGH!
This directly violates the ACPI spec.

Use __FBSDID().

Brought to you by: a boring talk at Ottawa Linux Symposium

MFi386: rev 1.56: remove break after return

Initial port to amd64 after repocopy from i386. Note that the
disassembler has not been updated yet, and will do some very strange
things. It does tracebacks (without function arguments due to regparm
calling conventions) if -fno-omit-frame-pointer is used (to come later).
This achieves basic functionality.

Approved by: re (amd64/* blanket)

Add code to ddb to allow backtracing an arbitrary thread.
(show thread {address})

Remove the IDLE kse state and replace it with a change in
the way threads sahre KSEs. Every KSE now has a thread, which is
considered its "owner" however a KSE may also be lent to other
threads in the same group to allow completion of in-kernel work.
n this case the owner remains the same and the KSE will revert to the
owner when the other work has been completed.

All creations of upcalls etc. is now done from
kse_reassign() which in turn is called from mi_switch or
thread_exit(). This means that special code can be removed from
msleep() and cv_wait().

kse_release() does not leave a KSE with no thread any more but
converts the existing thread into teh KSE's owner, and sets it up
for doing an upcall. It is just inhibitted from being scheduled until
there is some reason to do an upcall.

Remove all trace of the kse_idle queue since it is no-longer needed.
"Idle" KSEs are now on the loanable queue.

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

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

fork_trampoline() marks a trap frame.

Submitted by: bde

Use proper type for a variable used as a DDB symbol.

Trim includes.

Submitted by: bde

Various style fixes, including moving db_print_backtrace() out of the
middle of the watchpoint code.

Submitted by: bde

Implement db_print_backtrace() if DDB is compiled into the kernel. This
MD function is just a wrapper around db_stack_trace_cmd() that prints out
a backtrace of curthread. Currently, this function is only implemented
on i386 and alpha (and the alpha version isn't quite tested yet, will do
that in a bit). Other changes:

- For i386, fix a bug in the raw frame address case. The eip we extract
from the passed in frame address does not match the frame we received.
Thus, instead of printing a bogus frame with the wrong eip, go ahead
and advance frame down to the same frame as the eip we are using.
- For alpha, attempt to add a way of doing a raw trace for alpha. Instead
of passing a frame address in 'addr', pass in a pointer to a structure
containing PC and KSP and use those to start the backtrace. The alpha
db_print_backtrace() uses asm to read in the current PC and KSP values
into such a request.

Tested on: i386
Requested by: many

Unwind the syscall_with_err_pushed tweak that jake did some time back.

OK'ed by: jake

Fixed some style bugs in the removal of __P(()). The main ones were
not removing tabs before "__P((", and not outdenting continuation lines
to preserve non-KNF lining up of code with parentheses. Switch to KNF
formatting and/or rewrap the whole prototype in some cases.

Remove __P.

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

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

Remove the Xresume* labels from the i386 interrupt handlers; the
code in ipl.s and icu_ipl.s that used them was removed when the
interrupt thread system was committed. Debuggers also knew about
Xresume* because these labels hide the real names of the interrupt
handlers (Xintr*), and debuggers need to special-case interrupt
handlers to get the interrupt frame.

Both gdb and ddb will now use the Xintr* and Xfastintr* symbols to
detect interrupt frames. Fast interrupt frames were never identified
correctly before, so this fixes the problem of the running stack
frame getting lost in a ddb or gdb trace generated from a fast
interrupt - e.g. when debugging a simple infinite loop in the kernel
using a serial console, the frame containing the loop would never
appear in a gdb or ddb trace.

Reviewed by: jhb, bde

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

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

No objection by: audit@, hackers@

MFC after: 2 weeks

Provide access to the IA32 hardware debug registers from the ddb
kernel debugger. Proper use of these registers allows setting
hardware watchpoints for use in kernel debugging.

MFC after: 2 weeks

- Add support for decoding syscall names. (Brought over from the new alpha
trace code that was brought over from NetBSD.)
- Check for "syscall_with_err_pushed" as the label prior to a syscall trap
frame rather than "Xlcall_syscall" and "Xint0x80_syscall". We don't
have a valid trapframe during the short range of code that those two
symbols now cover.
- Simplify db_next_frame() to avoid duplicating the code for the different
trap frame types.
- Don't try to trace a swapped-out process. (Brought over from NetBSD via
the new alpha trace code.)

- One can now specify the decimal pid of a process to trace as a parameter.
Since pid's are not in the kernel address space, this doesn't conflict
with the funcionality of specifying an arbitrary frame pointer to the
trace command.
- If the first function of a backtrace maps to fork_trampoline, then this
is a newly fork'd process that has not been executed yet, so just print
out the first frame and then return for that case.
- Lower the default count from 65535 to 1024. ddb doesn't trace into
userland, and if the stack gets hosed and starts looping it's less
annoying.

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

Reviewed by: peter

When SMPng was first committed, we removed 'cpl' from the interrupt
frame. Teach ddb about this as there is one less word for it to skip
over when finding a trapframe on the interrupt frame stack.

Catch a few alternative names for the syscall entry frame, eg: post-ELF
and int $0x80 entry methods.

$Id$ -> $FreeBSD$

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>

Fix warnings in preparation for adding -Wall -Wcast-qual to the
kernel compile

Fix warnings in preparation for adding -Wall -Wcast-qual to the
kernel compile.

This commit includes significant work to proper handle const arguments
for the DDB symbol routines.

%n in a comment was a poor abbreviation for Immediate-byte-signed,
especially now that %n format has almost gone away.

Use not-so-new printf formats %r and/or %z instead of %n and/or %+x.

Fixed bogus type of valuep in struct db_variable. It was `int *' and
became `long *' for alpha, but should always have been `db_expr_t *'.
Fixed variable types to match.

This commit fixes various 64bit portability problems required for
FreeBSD/alpha. The most significant item is to change the command
argument to ioctl functions from int to u_long. This change brings us
inline with various other BSD versions. Driver writers may like to
use (__FreeBSD_version == 300003) to detect this change.

The prototype FreeBSD/alpha machdep will follow in a couple of days
time.

Fixed wrong limits for the kernel text in db_numargs(). The
interval [VM_MIN_KERNEL_ADDRESS, etext] was used instead of
[btext, etext). Added a comment about this being completely
wrong for LKMs. This only affects interpreting the instructions
after the return to attempt decide the number of args. The
attempt usually fails anyway.

Moved declaration of etext from <machine/md_var.h> to <machine/cpu.h>
and fixed everything that dependended on it being declared in the old
place. It is used in "machine-independent" code in subr_prof.c.

Moved declaration of btext from subr_prof.c to <machine/cpu.h>. It
is machine-dependent.

Revert my previous commit about using CS_SECURE macro.
Requested by: Bruce.

Use CS_SECURE macro.
Reviewed by: John Dyson

Removed unused #includes.

Remove the curproc printing on trap/interrupt/etc. It's outlived it's
usefulness, and there were problems with it anyway.

Found by: bde

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!

Add missing #include <machine/segments.h> for ISPL and SEL_UPL macros

Print function args in the current radix instead of always in hex.

Print the stack pointer together with the frame pointer in the trap,
syscall and interrupt messages. The frame pointer is not very useful
for locating syscall args since syscall functions don't have a frame
pointer.

Print all the numbers in the trap, syscall and interrupt messages in
the default radix. The syscall number was confusing because it was
printed in decimal.

Use %#n format more and 0x%x less. 0x%x of course doesn't work with
a variable radix. ddb is now fairly consistent about using %+#n to
print all numbers. It omits the '+' for signed numbers the '#' in a
few cases (e.g., for function args) to save space.

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

This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.

Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>

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.

Fixed traceback for the following cases:
- legitimate null frames from idle() (traceback was aborted after a null
pointer trap)
- second instruction of normal function prologue, and last instruction of
a function (caller wasn't reported).

Reviewed by: davidg

Fix a small logic bug that caused the arguments of the previous frame to
be used instead of the ones for the current frame if a breakpoint had been
set at the entry to a function.

Rewrote most of the ddb stack traceback code. These changes are smarter
about decoding trap/syscall/interrupt frames and generally works better
than the previous stuff.
Removed some special (incorrect) frobbing of the frame pointer that
was messing some things up with the new traceback code.

Staticized. Moved some ero-initialized values to the bss.

Added prototypes.

Remove trailing whitespace.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'. Fix all the bugs found. There were no serious
ones.

Slight change to include file order to accommodate upcoming changes.

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

Fixed various prototype problems with the pmap functions and the subsequent
problems that fixing them caused.

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" 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).

Convert syscall to trapframe. Based on work done by John Brezak.

Make everything compile with -Wtraditional. Make it easier to distribute
a binary link-kit. Make all non-optional options (pagers, procfs) standard,
and update LINT to reflect new symtab requirements.

NB: -Wtraditional will henceforth be forgotten. This editing pass was
primarily intended to detect any constructions where the old code might
have been relying on traditional C semantics or syntax. These were all
fixed, and the result of fixing some of them means that -Wall is now a
realistic possibility within a few weeks.

Removed all patch kit headers, sccsid and rcsid strings, put $Id$ in, some
minor cleanup. Added $Id$ to files that did not have any version info, etc

Initial import, 0.1 + pk 0.2.4-B1