ABIs:
- Store the FPU initial control word in the pcb for each thread.
- When first using the FPU, load the initial control word after restoring
the clean state if it is not the standard control word.
- Provide a correct control word for Linux/i386 binaries under
FreeBSD/amd64.
- Adjust the control word returned for fpugetregs()/npxgetregs() when a
thread hasn't used the FPU yet to reflect the real initial control
word for the current ABI.
- The Linux/i386 ABI for FreeBSD/i386 now properly sets the right control
word instead of trashing whatever the current state of the FPU is.
Reviewed by: bde
are used by glibc. This silents the message "2.4+ kernel w/o ELF notes?"
from some programs at start, among them are top and pkill.
Do the assignment of the vector entries in elf_linux_fixup()
as it is done in glibc.
Fix some minor style issues.
Submitted by: Marcin Cieslak <saper at SYSTEM PL>
Approved by: kib (mentor)
MFC after: 1 week
Change types used in the linux' struct msghdr and struct cmsghdr
definitions to the properly-sized architecture-specific types.
Move ancillary data handler from linux_sendit() to linux_sendmsg().
Submitted by: dchagin
Add a custom version of copyiniov() to deal with the 32-bit iovec
pointers from userland (to be used later).
Adjust prototypes for linux_readv() and linux_writev() to use new
l_iovec32 definition and to match actual linux code. In particular,
use ulong for fd (why ?).
Submitted by: dchagin
of the ABI of the currently executing image. Change some places to test
the flags instead of explicit comparing with address of known sysentvec
structures to determine ABI features.
Discussed with: dchagin, imp, jhb, peter
- Use `fildes[2]' instead of `*fildes' to make more clear that pipe(2)
fills an array with two descriptors.
- Remove EFAULT from the manual page. Because of the current calling
convention, pipe(2) raises a segmentation fault when an invalid
address is passed.
- Introduce kern_pipe() to make it easier for binary emulations to
implement pipe(2).
- Make Linux binary emulation use kern_pipe(), which means we don't have
to recover td_retval after calling the FreeBSD system call.
Approved by: rdivacky
Discussed on: arch
Looking at our source code history, it seems the uname(),
getdomainname() and setdomainname() system calls got deprecated
somewhere after FreeBSD 1.1, but they have never been phased out
properly. Because we don't have a COMPAT_FREEBSD1, just use
COMPAT_FREEBSD4.
Also fix the Linuxolator to build without the setdomainname() routine by
just making it call userland_sysctl on kern.domainname. Also replace the
setdomainname()'s implementation to use this approach, because we're
duplicating code with sysctl_domainname().
I wasn't able to keep these three routines working in our
COMPAT_FREEBSD32, because that would require yet another keyword for
syscalls.master (COMPAT4+NOPROTO). Because this routine is probably
unused already, this won't be a problem in practice. If it turns out to
be a problem, we'll just restore this functionality.
Reviewed by: rdivacky, kib
It is required for async cancellation to work.
Fix PROC_LOCK leak in linux_tgkill when signal delivery attempt is made
to not linux process.
Do not call em_find(p, ...) with p unlocked.
Move common code for linux_tkill() and linux_tgkill() into
linux_do_tkill().
Change linux siginfo_t definition to match actual linux one. Extend
uid fields to 4 bytes from 2. The extension does not change structure
layout and is binary compatible with previous definition, because i386
is little endian, and each uid field has 2 byte padding after it.
Reported by: Nicolas Joly <njoly pasteur fr>
Submitted by: dchangin
MFC after: 1 month
user-mode pointers. Change types used in the structures definitions to
properly-sized architecture-specific types.
Submitted by: dchagin
MFC after: 1 week
to the C99 style. At least, it is easier to read sysent definitions
that way, and search for the actual instances of sigcode etc.
Explicitely initialize sysentvec.sv_maxssiz that was missed in most
sysvecs.
No objection from: jhb
MFC after: 1 month
location in GDT where the segment descriptor from pcb_gs32sd is
copied, and the location is in GDT local to CPU.
Noted and reviewed by: peter
MFC after: 1 week
l_ucontext. To restore the registers content, trampoline needs to
dereference uc_mcontext instead of taking some undefined values from
l_ucontext.
Submitted by: Dmitry Chagin <dchagin@>
MFC after: 1 week
the 32bit images on amd64.
Change the semantic of the PCB_32BIT pcb flag to request the context
switch code to operate on the segment registers. Its previous meaning
of saving or restoring the %gs base offset is assigned to the new
PCB_GS32BIT flag.
FreeBSD 32bit image activator sets the PCB_32BIT flag, while Linux 32bit
emulation sets PCB_32BIT | PCB_GS32BIT.
Reviewed by: peter
MFC after: 2 weeks
what Linux does. This is because robust futexes are mostly
userspace thing which we cannot alter. Two syscalls maintain
pointer to userspace list and when process exits a routine
walks this list waking up processes sleeping on futexes
from that list.
Reviewed by: kib (mentor)
MFC after: 1 month
ABI and the direction flag, that is it now assumes that the direction
flag is cleared at the entry of a function and it doesn't clear once
more if needed. This new behaviour conforms to the i386/amd64 ABI.
Modify the signal handler frame setup code to clear the DF {e,r}flags
bit on the amd64/i386 for the signal handlers.
jhb@ noted that it might break old apps if they assumed DF == 1 would be
preserved in the signal handlers, but that such apps should be rare and
that older versions of gcc would not generate such apps.
Submitted by: Aurelien Jarno <aurelien aurel32 net>
PR: 121422
Reviewed by: jhb
MFC after: 2 weeks
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential. Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
Together with the sys/i386/i386/trap.c rev. 1.306 it fixes the PR.
Submitted by: rdivacky
Suggested by: jhb
Sponsored by: Google Summer of Code 2007
PR: kern/77710
Approved by: re (kensmith)
3 arguments, but we had forgotten the second argument. Also make the
Linux statfs64 struct depend on the architecture because it has an
extra 4 bytes padding on amd64 compared to i386.
The three argument fix is from David Taylor, the struct statfs64
stuff is my fault. With this patch I can install i386 Linux matlab
on an amd64 machine.
Submitted by: David Taylor <davidt_at_yadt.co.uk>
Approved by: re (kensmith)
with Linux 2.6 emulation. This shall be reimplemented once FreeBSD gets
native scheduler affinity syscalls.
Submitted by: rdivacky
Reviewed by: jkim
Sponsored by: Google Summer of Code 2007
Approved by: re (kensmith)
kernels exposed by the recent fixes to resource limits for 32-bit processes
on 64-bit kernels:
- Let ABIs expose their maximum stack size via a new pointer in sysentvec
and use that in preference to maxssiz during exec() rather than always
using maxssiz for all processses.
- Apply the ABI's limit fixup to the previous stack size when adjusting
RLIMIT_STACK to determine if the existing mapping for the stack needs to
be grown or shrunk (as well as how much it should be grown or shrunk).
Approved by: re (kensmith)
- Use thread_lock() rather than sched_lock for per-thread scheduling
sychronization.
- Use the per-process spinlock rather than the sched_lock for per-process
scheduling synchronization.
Tested by: kris, current@
Tested on: i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
Implement all futex atomic operations in assembler to not depend on the
fuword() that does not allow to distinguish between -1 and failure return.
Correctly return 0 from atomic operations on success.
In collaboration with: rdivacky
Tested by: Scot Hetzel <swhetzel gmail com>, Milos Vyletel <mvyletel mzm cz>
Sponsored by: Google SoC 2007
processes under 64-bit kernels). Previously, each 32-bit process overwrote
its resource limits at exec() time. The problem with this approach is that
the new limits affect all child processes of the 32-bit process, including
if the child process forks and execs a 64-bit process. To fix this, don't
ovewrite the resource limits during exec(). Instead, sv_fixlimits() is
now replaced with a different function sv_fixlimit() which asks the ABI to
sanitize a single resource limit. We then use this when querying and
setting resource limits. Thus, if a 32-bit process sets a limit, then
that new limit will be inherited by future children. However, if the
32-bit process doesn't change a limit, then a future 64-bit child will
see the "full" 64-bit limit rather than the 32-bit limit.
MFC is tentative since it will break the ABI of old linux.ko modules (no
other modules are affected).
MFC after: 1 week
passed zero as exit signal.
GCC 4.2 changes the kernel data segment layout not to have 0
in that memory location. This code ran by luck before and now
the luck has run out.
Dont "return" in linux_clone() after we forked the new process in a case
of problems. Move the copyout of p2->p_pid outside the emul_lock coverage.
Submitted by: Roman Divacky
Linux does not check file descriptor when MAP_ANONYMOUS is set.
This should fix recent LTP test regressions.
Reported by: Scot Hetzel (swhetzel at gmail dot com)
netchild
- PROT_READ, PROT_WRITE, or PROT_EXEC implies PROT_READ and PROT_EXEC.
Linux/ia64's i386 emulation layer does this and it complies with Linux
header files. This fixes mmap05 LTP test case on amd64.
- Do not adjust stack size when failure has occurred.
- Synchronize i386 mmap/mprotect with amd64.
setrunqueue() was mostly empty. The few asserts and thread state
setting were moved to the individual schedulers. sched_add() was
chosen to displace it for naming consistency reasons.
- Remove adjustrunqueue, it was 4 lines of code that was ifdef'd to be
different on all three schedulers where it was only called in one place
each.
- Remove the long ifdef'd out remrunqueue code.
- Remove the now redundant ts_state. Inspect the thread state directly.
- Don't set TSF_* flags from kern_switch.c, we were only doing this to
support a feature in one scheduler.
- Change sched_choose() to return a thread rather than a td_sched. Also,
rely on the schedulers to return the idlethread. This simplifies the
logic in choosethread(). Aside from the run queue links kern_switch.c
mostly does not care about the contents of td_sched.
Discussed with: julian
- Move the idle thread loop into the per scheduler area. ULE wants to
do something different from the other schedulers.
Suggested by: jhb
Tested on: x86/amd64 sched_{4BSD, ULE, CORE}.
Dont expose em->shared to the outside world before its properly
initialized. Might not affect anything but its at least a better
coding style.
Dont expose em via p->p_emuldata until its properly initialized.
This also enables us to get rid of some locking and simplify the
code because we are workin on a local copy.
In linux_fork and linux_vfork create the process in stopped state
to be sure that the new process runs with fully initialized emuldata
structure [1]. Also fix the vfork (both in linux_clone and linux_vfork)
race that could result in never woken up process [2].
Reported by: Scot Hetzel [1]
Suggested by: jhb [2]
Reviewed by: jhb (at least some important parts)
Submitted by: rdivacky
Tested by: Scot Hetzel (on amd64)
Change 2 comments (in the new code) to comply to style(9).
Suggested by: jhb
Bring the linux mmap code more into line with how linux (2.4.x) behaves.
Tested by: Scot Hetzel <swhetzel@gmail.com> on amd64 without PROT_EXEC
Additionally to the i386 version always use PROT_EXEC in the mapping like the
previous version of the amd64 code did. We need to examinate this further to
decide what the right thing to do is. For now this fixes several problems in
the LTP test runs and should behave regarding PROT_EXEC like before.
system calls on the amd64 architecture.
Some minor white space tweaks for consistency with other syscalls.master
files.
Obtained from: TrustedBSD Project
- Move linux_nanosleep() from src/sys/amd64/linux32/linux32_machdep.c to
src/sys/compat/linux/linux_time.c.
- Validate timespec ranges before use as Linux kernel does.
- Fix l_timespec structure.
- Clean up style(9) nits.
linux siginfo structure. l_sigval uses a l_uintptr_t for sival_ptr so
that sival_ptr is the right size for linux32 on amd64. Since no code
currently uses 'lsi_ptr' this is just a cosmetic nit rather than a bug
fix.
dynamic nature (if no native aio code is available, the linux part
returns ENOSYS because of missing requisites) should be solved differently
than it is.
All this will be done in P4.
Not included in this commit is a backout of the changes to the native aio
code (removing static in some places). Those changes (and some more) will
also be needed when the reworked linux aio stuff will reenter the tree.
Requested by: rwatson
Discussed with: rwatson
Implement the linux_io_* syscalls (AIO). They are only enabled if the native
AIO code is available (either compiled in to the kernel or as a module) at
the time the functions are used. If the AIO stuff is not available there
will be a ENOSYS.
From the submitter:
---snip---
DESIGN NOTES:
1. Linux permits a process to own multiple AIO queues (distinguished by
"context"), but FreeBSD creates only one single AIO queue per process.
My code maintains a request queue (STAILQ of queue(3)) per "context",
and throws all AIO requests of all contexts owned by a process into
the single FreeBSD per-process AIO queue.
When the process calls io_destroy(2), io_getevents(2), io_submit(2) and
io_cancel(2), my code can pick out requests owned by the specified context
from the single FreeBSD per-process AIO queue according to the per-context
request queues maintained by my code.
2. The request queue maintained by my code stores contrast information between
Linux IO control blocks (struct linux_iocb) and FreeBSD IO control blocks
(struct aiocb). FreeBSD IO control block actually exists in userland memory
space, required by FreeBSD native aio_XXXXXX(2).
3. It is quite troubling that the function io_getevents() of libaio-0.3.105
needs to use Linux-specific "struct aio_ring", which is a partial mirror
of context in user space. I would rather take the address of context in
kernel as the context ID, but the io_getevents() of libaio forces me to
take the address of the "ring" in user space as the context ID.
To my surprise, one comment line in the file "io_getevents.c" of
libaio-0.3.105 reads:
Ben will hate me for this
REFERENCE:
1. Linux kernel source code: http://www.kernel.org/pub/linux/kernel/v2.6/
(include/linux/aio_abi.h, fs/aio.c)
2. Linux manual pages: http://www.kernel.org/pub/linux/docs/manpages/
(io_setup(2), io_destroy(2), io_getevents(2), io_submit(2), io_cancel(2))
3. Linux Scalability Effort: http://lse.sourceforge.net/io/aio.html
The design notes: http://lse.sourceforge.net/io/aionotes.txt
4. The package libaio, both source and binary:
http://rpmfind.net/linux/rpm2html/search.php?query=libaio
Simple transparent interface to Linux AIO system calls.
5. Libaio-oracle: http://oss.oracle.com/projects/libaio-oracle/
POSIX AIO implementation based on Linux AIO system calls (depending on
libaio).
---snip---
Submitted by: Li, Xiao <intron@intron.ac>
but further on -current (still not successful, but a step into the right
direction).
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Tested by: Paul Mather <paul@gromit.dlib.vt.edu>
we can do the stuff we need to do with linux processes at fork and
don't panic the kernel at exit of the child.
Submitted by: rdivacky
Tested with: tst-vfork* (glibc regression tests)
Tested by: netchild
handling for amd64 in the common code. The MD parts for amd64 are still
outstanding, but at least this fixes some panics on amd64.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Tested by: bsam
- Send the systrace_args files for all the compat ABIs to /dev/null for
now. Right now makesyscalls.sh generates a file with a hardcoded
function name, so it wouldn't work for any of the ABIs anyway. Probably
the function name should be configurable via a 'systracename' variable
and the functions should be stored in a function pointer in the sysvec
structure.
- TLS - complete
- pid/tid mangling - complete
- thread area - complete
- futexes - complete with issues
- clone() extension - complete with some possible minor issues
- mq*/timer*/clock* stuff - complete but untested and the mq* stuff is
disabled when not build as part of the kernel with native FreeBSD mq*
support (module support for this will come later)
Tested with:
- linux-firefox - works, tested
- linux-opera - works, tested
- linux-realplay - doesnt work, issue with futexes
- linux-skype - doesnt work, issue with futexes
- linux-rt2-demo - works, tested
- linux-acroread - doesnt work, unknown reason (coredump) and sometimes
issue with futexes
- various unix utilities in linux-base-gentoo3 and linux-base-fc4:
everything tried worked
On amd64 not everything is supported like on i386, the catchup is planned for
later when the remaining bugs in the new functions are fixed.
To test this new stuff, you have to run
sysctl compat.linux.osrelease=2.6.16
to switch back use
sysctl compat.linux.osrelease=2.4.2
Don't switch while running a linux program, strange things may or may not
happen.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Some suggestions/help by: jhb, kib, manu@NetBSD.org, netchild
compat.linux.osrelease is changed to "2.6.16" or similar).
On amd64 not everything is supported like on i386, the catchup is planned for
later when the remaining bugs in the new functions are fixed.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
mark system calls as being MPSAFE:
- Stop conditionally acquiring Giant around system call invocations.
- Remove all of the 'M' prefixes from the master system call files.
- Remove support for the 'M' prefix from the script that generates the
syscall-related files from the master system call files.
- Don't explicitly set SYF_MPSAFE when registering nfssvc.
ibcs2_getdents(), ibcs2_read(), ogetdirentries(), svr4_sys_getdents(),
and svr4_sys_getdents64() similar to that in getdirentries().
- Mark ibcs2_getdents(), ibcs2_read(), linux_getdents(), linux_getdents64(),
linux_readdir(), ogetdirentries(), svr4_sys_getdents(), and
svr4_sys_getdents64() MPSAFE.
to a copied-in copy of the 'union semun' and a uioseg to indicate which
memory space the 'buf' pointer of the union points to. This is then used
in linux_semctl() and svr4_sys_semctl() to eliminate use of the stackgap.
- Mark linux_ipc() and svr4_sys_semsys() MPSAFE.
from going away. mount(2) is now MPSAFE.
- Expand the scope of Giant some in unmount(2) to protect the mp structure
(or rather, to handle concurrent unmount races) from going away.
umount(2) is now MPSAFE, as well as linux_umount() and linux_oldumount().
- nmount(2) and linux_mount() were already MPSAFE.
syscalls. This way there will be a log message printed to the console
(this time for real).
Note: UNIMPL should be used for syscalls we do not implement ever, e.g.
syscalls to load linux kernel modules.
Submitted by: rdivacky
Sponsored by: Goole SoC 2006
P4 IDs: 99600, 99602
Update of syscall.master:
o Adding of several new dummy syscalls (268-310)
o Synchronization of amd64 syscall.master with i386 one
o Auditing added to amd64 syscall.master
o Change auditing type for lstat syscall (bugfix). [1]
P4-Changes: 98672, 98674
Noticed by: rwatson [1]
Sponsored by: Google SoC 2006
Submitted by: rdivacky
the callers if the exec either succeeds or fails early.
- Move the code to call exit1() if the exec fails after the vmspace is
gone to the bottom of kern_execve() to cut down on some code duplication.
with flags bitfield and set BI_CAN_EXEC_DYN flag for all brands that usually
allow executing elf dynamic binaries (aka shared libraries). When it is
requested to execute ET_DYN elf image check if this flag is on after we
know the elf brand allowing execution if so.
PR: kern/87615
Submitted by: Marcin Koziej <creep@desk.pl>
which existed to cleanup the linux_osname mutex. Now that MTX_SYSINIT()
has grown a SYSUNINIT to destroy mutexes on unload, the extra destroy here
was redundant and resulted in panics in debug kernels.
MFC after: 1 week
Reported by: Goran Gajic ggajic at afrodita dot rcub dot bg dot ac dot yu
changes in MD code are trivial, before this change, trapsignal and
sendsig use discrete parameters, now they uses member fields of
ksiginfo_t structure. For sendsig, this change allows us to pass
POSIX realtime signal value to user code.
2. Remove cpu_thread_siginfo, it is no longer needed because we now always
generate ksiginfo_t data and feed it to libpthread.
3. Add p_sigqueue to proc structure to hold shared signals which were
blocked by all threads in the proc.
4. Add td_sigqueue to thread structure to hold all signals delivered to
thread.
5. i386 and amd64 now return POSIX standard si_code, other arches will
be fixed.
6. In this sigqueue implementation, pending signal set is kept as before,
an extra siginfo list holds additional siginfo_t data for signals.
kernel code uses psignal() still behavior as before, it won't be failed
even under memory pressure, only exception is when deleting a signal,
we should call sigqueue_delete to remove signal from sigqueue but
not SIGDELSET. Current there is no kernel code will deliver a signal
with additional data, so kernel should be as stable as before,
a ksiginfo can carry more information, for example, allow signal to
be delivered but throw away siginfo data if memory is not enough.
SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
not be caught or masked.
The sigqueue() syscall allows user code to queue a signal to target
process, if resource is unavailable, EAGAIN will be returned as
specification said.
Just before thread exits, signal queue memory will be freed by
sigqueue_flush.
Current, all signals are allowed to be queued, not only realtime signals.
Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64
exec_copyin_strings() to catch up to rev 1.266 of kern_exec.c. This fixes
panics on amd64 with compat binaries since exec_free_args() was freeing
more memory than these functions were allocating and the mismatch could
cause memory to be freed out from under other concurrent execs.
Approved by: re (scottl)
audit event identifier associated with each system call, which will
be stored by makesyscalls.sh in the sy_auevent field of struct sysent.
For now, default the audit identifier on all system calls to AUE_NULL,
but in the near future, other BSM event identifiers will be used. The
mapping of system calls to event identifiers is many:one due to
multiple system calls that map to the same end functionality across
compatibility wrappers, ABI wrappers, etc.
Submitted by: wsalamon
Obtained from: TrustedBSD Project
validation error in procfs/linprocfs that can be exploited by local
users to cause a kernel panic. All versions of FreeBSD with the patch
referenced in SA-04:17.procfs have this bug, but versions without that
patch have a more serious bug instead. This problem only affects
systems on which procfs or linprocfs is mounted.
Found by: Coverity Prevent analysis tool
Security: Local DOS
pointers in argv and envv in userland and use that together with
kern_execve() and exec_free_args() to implement linux_execve() for the
amd64/linux32 ABI without using the stackgap.
- Implement linux_nanosleep() using the recently added kern_nanosleep().
- Use linux_emul_convpath() instead of linux_emul_find() in
exec_linux_imgact_try().
Tested by: cokane
Silence on: amd64
copies arguments into the kernel space and one that operates
completely in the kernel space;
o use kernel-only version of execve(2) to kill another stackgap in
linuxlator/i386.
Obtained from: DragonFlyBSD (partially)
MFC after: 2 weeks
the raw values including for child process statistics and only compute the
system and user timevals on demand.
- Fix the various kern_wait() syscall wrappers to only pass in a rusage
pointer if they are going to use the result.
- Add a kern_getrusage() function for the ABI syscalls to use so that they
don't have to play stackgap games to call getrusage().
- Fix the svr4_sys_times() syscall to just call calcru() to calculate the
times it needs rather than calling getrusage() twice with associated
stackgap, etc.
- Add a new rusage_ext structure to store raw time stats such as tick counts
for user, system, and interrupt time as well as a bintime of the total
runtime. A new p_rux field in struct proc replaces the same inline fields
from struct proc (i.e. p_[isu]ticks, p_[isu]u, and p_runtime). A new p_crux
field in struct proc contains the "raw" child time usage statistics.
ruadd() has been changed to handle adding the associated rusage_ext
structures as well as the values in rusage. Effectively, the values in
rusage_ext replace the ru_utime and ru_stime values in struct rusage. These
two fields in struct rusage are no longer used in the kernel.
- calcru() has been split into a static worker function calcru1() that
calculates appropriate timevals for user and system time as well as updating
the rux_[isu]u fields of a passed in rusage_ext structure. calcru() uses a
copy of the process' p_rux structure to compute the timevals after updating
the runtime appropriately if any of the threads in that process are
currently executing. It also now only locks sched_lock internally while
doing the rux_runtime fixup. calcru() now only requires the caller to
hold the proc lock and calcru1() only requires the proc lock internally.
calcru() also no longer allows callers to ask for an interrupt timeval
since none of them actually did.
- calcru() now correctly handles threads executing on other CPUs.
- A new calccru() function computes the child system and user timevals by
calling calcru1() on p_crux. Note that this means that any code that wants
child times must now call this function rather than reading from p_cru
directly. This function also requires the proc lock.
- This finishes the locking for rusage and friends so some of the Giant locks
in exit1() and kern_wait() are now gone.
- The locking in ttyinfo() has been tweaked so that a shared lock of the
proctree lock is used to protect the process group rather than the process
group lock. By holding this lock until the end of the function we now
ensure that the process/thread that we pick to dump info about will no
longer vanish while we are trying to output its info to the console.
Submitted by: bde (mostly)
MFC after: 1 month
with the COMPAT_LINUX32 option. This is largely based on the i386 MD Linux
emulations bits, but also builds on the 32-bit FreeBSD and generic IA-32
binary emulation work.
Some of this is still a little rough around the edges, and will need to be
revisited before 32-bit and 64-bit Linux emulation support can coexist in
the same kernel.
