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/*--------------------------------------------------------------------*/
/*--- Support for doing system calls. syscall-x86-freebsd.S ---*/
/*--------------------------------------------------------------------*/
/*
This file is part of Valgrind, a dynamic binary instrumentation
framework.
Copyright (C) 2000-2007 Julian Seward
jseward@acm.org
Copyright (C) 2018-2021 Paul Floyd
pjfloyd@wanadoo.fr
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
The GNU General Public License is contained in the file COPYING.
*/
#include "pub_core_basics_asm.h"
#if defined(VGP_x86_freebsd)
#include "pub_core_vkiscnums_asm.h"
#include "libvex_guest_offsets.h"
/*----------------------------------------------------------------*/
/*
Perform a syscall for the client. This will run a syscall
with the client's specific per-thread signal mask.
The structure of this function is such that, if the syscall is
interrupted by a signal, we can determine exactly what
execution state we were in with respect to the execution of
the syscall by examining the value of %eip in the signal
handler. This means that we can always do the appropriate
thing to precisely emulate the kernel's signal/syscall
interactions.
The syscall number is taken from the argument, even though it
should also be in regs->m_eax. The syscall result is written
back to regs->m_eax on completion.
Returns 0 if the syscall was successfully called (even if the
syscall itself failed), or a -ve error code if one of the
sigprocmasks failed (there's no way to determine which one
failed).
VG_(fixup_guest_state_after_syscall_interrupted) does the
thread state fixup in the case where we were interrupted by a
signal.
Prototype:
Int ML_(do_syscall_for_client_WRK)(
Int syscallno, // ebp+8
void* guest_state, // ebp+12
const vki_sigset_t *sysmask, // ebp+16
const vki_sigset_t *postmask, // ebp+20
Int sigsetSzB) // ebp+24
Note that sigsetSzB is totally ignored (and irrelevant).
*/
/* from vki-darwin.h, checked at startup by m_vki.c */
#define VKI_SIG_SETMASK 3
.globl ML_(do_syscall_for_client_WRK)
ML_(do_syscall_for_client_WRK):
/* establish stack frame */
push %ebp
mov %esp, %ebp
subl $8, %esp /* 16-byte align stack */
1: /* Even though we can't take a signal until the
sigprocmask completes, start the range early.
If eip is in the range [1,2), the syscall hasn't been started yet */
/* Set the signal mask which should be current during the syscall. */
pushl 20(%ebp)
pushl 16(%ebp)
pushl $VKI_SIG_SETMASK
pushl $0xcafebabe /* totally fake return address */
movl $__NR_sigprocmask, %eax
int $0x80
jc 7f /* sigprocmask failed */
addl $16,%esp
/* Copy syscall parameters to the stack - assume no more than 8
* plus the return address */
/* do_syscall8 */
/* stack is currently aligned assuming 8 parameters */
movl 12(%ebp), %edx
movl OFFSET_x86_ESP(%edx), %edx /* edx = simulated ESP */
movl 28+4(%edx), %eax
pushl %eax
movl 24+4(%edx), %eax
pushl %eax
movl 20+4(%edx), %eax
pushl %eax
movl 16+4(%edx), %eax
pushl %eax
movl 12+4(%edx), %eax
pushl %eax
movl 8+4(%edx), %eax
pushl %eax
movl 4+4(%edx), %eax
pushl %eax
movl 0+4(%edx), %eax
pushl %eax
/* return address */
movl 0(%edx), %eax
pushl %eax
/* Put syscall number in eax */
movl 8(%ebp), %eax
/* If eip==2, then the syscall was either just about to start,
or was interrupted and the kernel was restarting it. */
2: int $0x80 /* UNIX (GrP fixme should be sysenter?) */
3: /* In the range [3, 4), the syscall result is in %eax and %edx and C,
but hasn't been committed to the thread state. */
setc 0(%esp) /* stash returned carry flag */
movl 12(%ebp), %ecx
movl %eax, OFFSET_x86_EAX(%ecx) /* save EAX to vex */
movl %edx, OFFSET_x86_EDX(%ecx) /* save EDX to vex */
/* save carry flag to vex */
subl $12, %esp
movl %ecx, 4(%esp)
movl $0, 0(%esp)
movb 12(%esp), %al
movb %al, 0(%esp)
call LibVEX_GuestX86_put_eflag_c
addl $12, %esp
4: /* Re-block signals. If eip is in [4,5), then the syscall is
complete and we needn't worry about it. */
/* Set up for __pthread_sigmask(SIG_SETMASK, postmask, NULL) */
pushl $0
pushl 20(%ebp)
pushl $VKI_SIG_SETMASK
pushl $0xcafef00d /* totally fake return address */
movl $__NR_sigprocmask, %eax
int $0x80 /* should be sysenter? */
jc 7f /* sigprocmask failed */
addl $16,%esp
5: /* now safe from signals */
movl $0, %eax /* SUCCESS */
movl %ebp, %esp
popl %ebp
ret
7: /* failure: return 0x8000 | error code */
/* Note that we enter here with %esp being 16 too low
(4 extra words on the stack). But because we're nuking
the stack frame now, that doesn't matter. */
andl $0x7FFF, %eax
orl $0x8000, %eax
movl %ebp, %esp
popl %ebp
ret
.section .rodata
/* export the ranges so that
VG_(fixup_guest_state_after_syscall_interrupted) can do the
right thing */
.globl ML_(blksys_setup)
.globl ML_(blksys_restart)
.globl ML_(blksys_complete)
.globl ML_(blksys_committed)
.globl ML_(blksys_finished)
ML_(blksys_setup): .long 1b
ML_(blksys_restart): .long 2b
ML_(blksys_complete): .long 3b
ML_(blksys_committed): .long 4b
ML_(blksys_finished): .long 5b
.previous
#endif // defined(VGP_x86_freebsd)
/* Let the linker know we don't need an executable stack */
MARK_STACK_NO_EXEC
/*--------------------------------------------------------------------*/
/*--- end ---*/
/*--------------------------------------------------------------------*/
|
