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https://github.com/Zenithsiz/ftmemsim-valgrind.git
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245 lines
6.8 KiB
ArmAsm
245 lines
6.8 KiB
ArmAsm
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##--------------------------------------------------------------------##
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##--- Support for doing system calls. x86-linux/syscall.S ---##
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##--------------------------------------------------------------------##
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/*
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This file is part of Valgrind, a dynamic binary instrumentation
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framework.
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Copyright (C) 2000-2005 Julian Seward
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jseward@acm.org
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307, USA.
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The GNU General Public License is contained in the file COPYING.
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*/
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#include "core_asm.h"
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#include "vki_unistd.h"
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#include "libvex_guest_offsets.h"
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.globl VG_(do_syscall)
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/*
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Perform a Linux syscall with int 0x80
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Syscall args are passed on the stack
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Int VG_(do_syscall)(Int syscall_no, UWord a1, UWord a2, UWord a3,
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UWord a4, UWord a5, UWord a6)
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This has no effect on the virtual machine; the assumption is
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that the syscall mechanism makes no useful changes to any
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register except %eax, which is returned. (Some kernels will
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change other registers randomly, but they're just compiler
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spill values.)
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*/
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VG_(do_syscall):
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push %esi
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push %edi
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push %ebx
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push %ebp
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movl 16+ 4(%esp),%eax
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movl 16+ 8(%esp),%ebx
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movl 16+12(%esp),%ecx
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movl 16+16(%esp),%edx
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movl 16+20(%esp),%esi
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movl 16+24(%esp),%edi
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movl 16+28(%esp),%ebp
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int $0x80
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popl %ebp
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popl %ebx
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popl %edi
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popl %esi
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ret
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/*
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Perform a clone system call. clone is strange because it has
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fork()-like return-twice semantics, so it needs special
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handling here.
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int VG_(clone)(int (*fn)(void *), void *child_stack, int flags, void *arg,
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0 4 8 12
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pid_t *child_tid, pid_t *parent_tid, vki_modify_ldt_t *)
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16 20 24
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*/
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.globl VG_(clone)
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VG_(clone):
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#define FSZ (4+4+4) /* frame size = retaddr+ebx+edi */
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push %ebx
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push %edi
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/* set up child stack with function and arg */
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movl 4+FSZ(%esp), %ecx /* child stack */
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movl 12+FSZ(%esp), %ebx /* fn arg */
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movl 0+FSZ(%esp), %eax /* fn */
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lea -8(%ecx), %ecx /* make space on stack */
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movl %ebx, 4(%ecx) /* fn arg */
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movl %eax, 0(%ecx) /* fn */
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/* get other args to clone */
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movl 8+FSZ(%esp), %ebx /* flags */
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movl 20+FSZ(%esp), %edx /* parent tid * */
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movl 16+FSZ(%esp), %edi /* child tid * */
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movl 24+FSZ(%esp), %esi /* modify_ldt_t * */
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movl $__NR_clone, %eax
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int $0x80
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testl %eax, %eax
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jnz 1f
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/* CHILD - call thread function */
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popl %eax
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call *%eax
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/* exit with result */
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movl %eax, %ebx
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movl $__NR_exit, %eax
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int $0x80
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/* Hm, exit returned */
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ud2
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1: /* PARENT or ERROR */
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pop %edi
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pop %ebx
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ret
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#undef FSZ
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.globl VG_(sigreturn)
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VG_(sigreturn):
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movl $__NR_rt_sigreturn, %eax
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int $0x80
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/*
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Perform a syscall for the client. This will run a syscall
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with the client's specific per-thread signal mask.
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The structure of this function is such that, if the syscall is
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interrupted by a signal, we can determine exactly what
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execution state we were in with respect to the execution of
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the syscall by examining the value of %eip in the signal
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handler. This means that we can always do the appropriate
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thing to precisely emulate the kernel's signal/syscall
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interactions.
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The syscall number is taken from the argument, even though it
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should also be in regs->m_eax. The syscall result is written
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back to regs->m_eax on completion.
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Returns 0 if the syscall was successfully called (even if the
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syscall itself failed), or a -ve error code if one of the
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sigprocmasks failed (there's no way to determine which one
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failed).
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VGA_(interrupted_syscall)() does the thread state fixup in the
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case where we were interrupted by a signal.
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Prototype:
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Int VGA_(_client_syscall)(Int syscallno, // 0
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void* guest_state, // 4
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const vki_sigset_t *sysmask, // 8
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const vki_sigset_t *postmask, // 12
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Int nsigwords) // 16
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*/
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/* from vki_arch.h */
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#define VKI_SIG_SETMASK 2
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.globl VGA_(_client_syscall)
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VGA_(_client_syscall):
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/* save callee-saved regs */
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push %esi
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push %edi
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push %ebx
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push %ebp
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#define FSZ ((4+1)*4) /* 4 args + ret addr */
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1: /* Even though we can't take a signal until the sigprocmask completes,
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start the range early.
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If eip is in the range [1,2), the syscall hasn't been started yet */
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/* Set the signal mask which should be current during the syscall. */
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movl $__NR_rt_sigprocmask, %eax
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movl $VKI_SIG_SETMASK, %ebx
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movl 8+FSZ(%esp), %ecx
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movl 12+FSZ(%esp), %edx
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movl 16+FSZ(%esp), %esi
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int $0x80
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testl %eax, %eax
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js 5f /* sigprocmask failed */
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movl 4+FSZ(%esp), %eax /* eax == ThreadState * */
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movl OFFSET_x86_EBX(%eax), %ebx
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movl OFFSET_x86_ECX(%eax), %ecx
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movl OFFSET_x86_EDX(%eax), %edx
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movl OFFSET_x86_ESI(%eax), %esi
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movl OFFSET_x86_EDI(%eax), %edi
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movl OFFSET_x86_EBP(%eax), %ebp
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movl 0+FSZ(%esp), %eax /* use syscallno argument rather than thread EAX */
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/* If eip==2, then the syscall was either just about to start,
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or was interrupted and the kernel was restarting it. */
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2: int $0x80
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3: /* In the range [3, 4), the syscall result is in %eax, but hasn't been
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committed to EAX. */
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movl 4+FSZ(%esp), %ebx
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movl %eax, OFFSET_x86_EAX(%ebx) /* save back to EAX */
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4: /* Re-block signals. If eip is in [4,5), then the syscall is complete and
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we needn't worry about it. */
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movl $__NR_rt_sigprocmask, %eax
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movl $VKI_SIG_SETMASK, %ebx
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movl 12+FSZ(%esp), %ecx
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xorl %edx, %edx
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movl 16+FSZ(%esp), %esi
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int $0x80
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5: /* now safe from signals */
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popl %ebp
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popl %ebx
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popl %edi
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popl %esi
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#undef FSZ
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ret
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.section .rodata
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/* export the ranges so that VGA_(interrupted_syscall) can do the
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right thing */
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.globl VGA_(blksys_setup)
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.globl VGA_(blksys_restart)
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.globl VGA_(blksys_complete)
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.globl VGA_(blksys_committed)
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.globl VGA_(blksys_finished)
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VGA_(blksys_setup): .long 1b
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VGA_(blksys_restart): .long 2b
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VGA_(blksys_complete): .long 3b
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VGA_(blksys_committed): .long 4b
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VGA_(blksys_finished): .long 5b
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.previous
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/* Let the linker know we don't need an executable stack */
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.section .note.GNU-stack,"",@progbits
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##--------------------------------------------------------------------##
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##--- end ---##
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##--------------------------------------------------------------------##
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