| ##--------------------------------------------------------------------## |
| ##--- Support routines for the JITter output. x86/helpers.S ---## |
| ##--------------------------------------------------------------------## |
| |
| /* |
| This file is part of Valgrind, an extensible x86 protected-mode |
| emulator for monitoring program execution on x86-Unixes. |
| |
| Copyright (C) 2000-2004 Julian Seward |
| jseward@acm.org |
| |
| 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, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307, USA. |
| |
| The GNU General Public License is contained in the file COPYING. |
| */ |
| |
| #include "core_asm.h" |
| |
| /* ------------------ SIMULATED CPU HELPERS ------------------ */ |
| /* A stubs for a return which we want to catch: a signal return. |
| returns and pthread returns. In the latter case, the thread's |
| return value is in %EAX, so we pass this as the first argument |
| to the request. In both cases we use the user request mechanism. |
| You need to to read the definition of VALGRIND_MAGIC_SEQUENCE |
| in valgrind.h to make sense of this. |
| |
| This isn't used in-place. It is copied into the client address space |
| at an arbitary address. Therefore, this code must be completely |
| position-independent. |
| */ |
| .global VG_(trampoline_code_start) |
| .global VG_(trampoline_code_length) |
| .global VG_(tramp_sigreturn_offset) |
| .global VG_(tramp_syscall_offset) |
| |
| VG_(trampoline_code_start): |
| sigreturn_start: |
| subl $20, %esp # allocate arg block |
| movl %esp, %edx # %edx == &_zzq_args[0] |
| movl $VG_USERREQ__SIGNAL_RETURNS, 0(%edx) # request |
| movl $0, 4(%edx) # arg1 |
| movl $0, 8(%edx) # arg2 |
| movl $0, 12(%edx) # arg3 |
| movl $0, 16(%edx) # arg4 |
| movl %edx, %eax |
| # and now the magic sequence itself: |
| roll $29, %eax |
| roll $3, %eax |
| rorl $27, %eax |
| rorl $5, %eax |
| roll $13, %eax |
| roll $19, %eax |
| # should never get here |
| ud2 |
| |
| # We can point our sysinfo stuff here |
| .align 16 |
| syscall_start: |
| int $0x80 |
| ret |
| tramp_code_end: |
| |
| .data |
| VG_(trampoline_code_length): |
| .long tramp_code_end - VG_(trampoline_code_start) |
| VG_(tramp_sigreturn_offset): |
| .long sigreturn_start - VG_(trampoline_code_start) |
| VG_(tramp_syscall_offset): |
| .long syscall_start - VG_(trampoline_code_start) |
| .text |
| |
| |
| /* Let the linker know we don't need an executable stack */ |
| .section .note.GNU-stack,"",@progbits |
| |
| ##--------------------------------------------------------------------## |
| ##--- end ---## |
| ##--------------------------------------------------------------------## |