Commit Graph

24 Commits

Author SHA1 Message Date
Konstantin Belousov
d6e029adbe In r197963, a race with thread being selected for signal delivery
while in kernel mode, and later changing signal mask to block the
signal, was fixed for sigprocmask(2) and ptread_exit(3). The same race
exists for sigreturn(2), setcontext(2) and swapcontext(2) syscalls.

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

Reviewed by:	davidxu
Tested by:	pho
MFC after:	1 month
2009-10-27 10:47:58 +00:00
Konstantin Belousov
a2622e5dc2 Restore the segment registers and segment base MSRs for amd64 syscall
return path only when neither thread was context switched while
executing syscall code nor syscall explicitely modified LDT or MSRs.

Save segment registers in trap handlers before interrupts are enabled,
to not allow context switches to happen before registers are saved.
Use separated byte in pcb for indication of fast/full return, since
pcb_flags are not synchronized with context switches.

The change puts back syscall microbenchmark numbers that were slowed
down after commit of the support for LDT on amd64.

Reviewed by:	jeff
Tested (and tested, and tested ...) by:	pho
Approved by:	re (kensmith)
2009-07-09 09:34:11 +00:00
Konstantin Belousov
2c66cccab7 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
2009-04-01 13:09:26 +00:00
John Baldwin
2ee8325f42 A better fix for handling different FPU initial control words for different
ABIs:
- Store the FPU initial control word in the pcb for each thread.
- When first using the FPU, load the initial control word after restoring
  the clean state if it is not the standard control word.
- Provide a correct control word for Linux/i386 binaries under
  FreeBSD/amd64.
- Adjust the control word returned for fpugetregs()/npxgetregs() when a
  thread hasn't used the FPU yet to reflect the real initial control
  word for the current ABI.
- The Linux/i386 ABI for FreeBSD/i386 now properly sets the right control
  word instead of trashing whatever the current state of the FPU is.

Reviewed by:	bde
2009-03-05 19:42:11 +00:00
David E. O'Brien
e6493bbebf 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
2009-01-31 11:37:21 +00:00
Konstantin Belousov
f98c3ea74e - When executing FreeBSD/amd64 binaries from FreeBSD/i386 or Linux/i386
processes, clear PCB_32BIT and PCB_GS32BIT bits [1].

- Reread the fs and gs bases from the msr unconditionally, not believing
  the values in pcb_fsbase and pcb_gsbase, since usermode may reload
  segment registers, invalidating the cache. [2].

Both problems resulted in the wrong fs base, causing wrong tls pointer
be dereferenced in the usermode.

Reported and tested by:	Vyacheslav Bocharov <adeepv at gmail com> [1]
Reported by:	Bernd Walter <ticsoat cicely7 cicely de>,
	Artem Belevich <fbsdlist at src cx>[2]
Reviewed by:	peter
MFC after:	3 days
2008-09-02 17:52:11 +00:00
Konstantin Belousov
8f4a1f3a83 Bring back the save/restore of the %ds, %es, %fs and %gs registers for
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
2008-07-30 11:30:55 +00:00
Peter Wemm
3d60169ef4 Protect the setting of the fsbase/gsbase MSR registers and the
pcb_[fg]sbase values with a critical section, like the rest of the kernel.
2008-03-23 22:44:56 +00:00
Konstantin Belousov
22eca0bf45 Since version 4.3, gcc changed its behaviour concerning the i386/amd64
ABI and the direction flag, that is it now assumes that the direction
flag is cleared at the entry of a function and it doesn't clear once
more if needed. This new behaviour conforms to the i386/amd64 ABI.

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

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

Submitted by:	Aurelien Jarno <aurelien aurel32 net>
PR:	121422
Reviewed by:	jhb
MFC after:	2 weeks
2008-03-13 10:54:38 +00:00
David Xu
c6511aea86 Move some declaration of 32-bit signal structures into file
freebsd32-signal.h, implement sigtimedwait and sigwaitinfo system calls.
2006-10-05 01:56:11 +00:00
Peter Wemm
79880f7327 Catch up to the system siginfo changes. Use a union for the ia32 layout
of siginfo just like the system one.  There are now two fields to copy
instead of one.
2005-12-06 23:06:29 +00:00
Ruslan Ermilov
160ebe8754 Catch up with the recent <sys/signal.h> change and make this compile. 2005-11-04 20:32:26 +00:00
David Xu
9104847f21 1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most
changes in MD code are trivial, before this change, trapsignal and
   sendsig use discrete parameters, now they uses member fields of
   ksiginfo_t structure. For sendsig, this change allows us to pass
   POSIX realtime signal value to user code.

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

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

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

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

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

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64
2005-10-14 12:43:47 +00:00
Peter Wemm
add121a476 Implement 32 bit getcontext/setcontext/swapcontext on amd64. I've added
stubs for ia64 to keep it compiling.  These are used by 32 bit apps such
as gdb.
2005-09-27 18:04:20 +00:00
Warner Losh
9a80fddc71 Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999 and email from Peter Wemm.

Approved by: core, peter
2004-04-05 23:55:14 +00:00
Peter Wemm
4fa84e0fb3 Catch up with some proc/procsig locking improvements that were made to the
i386 version and were not merged over.
2004-02-21 23:34:42 +00:00
David Xu
a30ec4b99c Make sigaltstack as per-threaded, because per-process sigaltstack state
is useless for threaded programs, multiple threads can not share same
stack.
The alternative signal stack is private for thread, no lock is needed,
the orignal P_ALTSTACK is now moved into td_pflags and renamed to
TDP_ALTSTACK.
For single thread or Linux clone() based threaded program, there is no
semantic changed, because those programs only have one kernel thread
in every process.

Reviewed by: deischen, dfr
2004-01-03 02:02:26 +00:00
Peter Wemm
3554ecf032 Catch up with the procsig locking changes elsewhere. We were doing
things like copyin/out with psp->ps_mtx held.  That was not good.

Approved by:  re (scottl)
2003-12-03 07:00:30 +00:00
Peter Wemm
4cd2d525e3 Move a MD 32 bit binary support routine into the MD areas. exec_setregs
is highly MD in an emulation environment since it operates on the host
environment.  Although the setregs functions are really for exec support
rather than signals, they deal with the same sorts of context and include
files.  So I put it there rather than create yet another file.
2003-11-08 07:43:44 +00:00
Peter Wemm
bf2f09ee97 The great s/npx/fpu/gi 2003-11-08 03:33:38 +00:00
Peter Wemm
46159d1fd6 Switch to using the emulator in the common compat area.
Still work-in-progress.
2003-08-23 00:04:53 +00:00
David E. O'Brien
56ae44c5df Use __FBSDID().
Brought to you by:	a boring talk at Ottawa Linux Symposium
2003-07-25 21:19:19 +00:00
Peter Wemm
9f0c4ab393 Deal with the user VM space expanding. 32 bit applications do not like
having their stack at the 512GB mark.  Give 4GB of user VM space for 32
bit apps.  Note that this is significantly more than on i386 which gives
only about 2.9GB of user VM to a process (1GB for kernel, plus page
table pages which eat user VM space).

Approved by: re (blanket)
2003-05-23 05:07:33 +00:00
Peter Wemm
d85631c4ac Add BASIC i386 binary support for the amd64 kernel. This is largely
stolen from the ia64/ia32 code (indeed there was a repocopy), but I've
redone the MD parts and added and fixed a few essential syscalls.  It
is sufficient to run i386 binaries like /bin/ls, /usr/bin/id (dynamic)
and p4.  The ia64 code has not implemented signal delivery, so I had
to do that.

Before you say it, yes, this does need to go in a common place.  But
we're in a freeze at the moment and I didn't want to risk breaking ia64.
I will sort this out after the freeze so that the common code is in a
common place.

On the AMD64 side, this required adding segment selector context switch
support and some other support infrastructure.  The %fs/%gs etc code
is hairy because loading %gs will clobber the kernel's current MSR_GSBASE
setting.  The segment selectors are not used by the kernel, so they're only
changed at context switch time or when changing modes.  This still needs
to be optimized.

Approved by:	re (amd64/* blanket)
2003-05-14 04:10:49 +00:00