204 lines
7.2 KiB
C
204 lines
7.2 KiB
C
/* DWARF2 EH unwinding support for AMD x86-64 and x86.
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Copyright (C) 2004-2019 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* Unwind shadow stack for -fcf-protection -mshstk. */
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#if defined __SHSTK__ && defined __CET__ && (__CET__ & 2) != 0
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# include "config/i386/shadow-stack-unwind.h"
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#endif
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/* Do code reading to identify a signal frame, and set the frame
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state data appropriately. See unwind-dw2.c for the structs.
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Don't use this at all if inhibit_libc is used. */
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#ifndef inhibit_libc
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/* There's no sys/ucontext.h for glibc 2.0, so no
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signal-turned-exceptions for them. There's also no configure-run for
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the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H. Using the
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target libc version macro should be enough. */
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#if defined __GLIBC__ && !(__GLIBC__ == 2 && __GLIBC_MINOR__ == 0)
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#include <signal.h>
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#include <sys/ucontext.h>
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#ifdef __x86_64__
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#define MD_FALLBACK_FRAME_STATE_FOR x86_64_fallback_frame_state
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static _Unwind_Reason_Code
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x86_64_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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unsigned char *pc = context->ra;
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struct sigcontext *sc;
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long new_cfa;
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/* movq $__NR_rt_sigreturn, %rax ; syscall. */
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#ifdef __LP64__
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#define RT_SIGRETURN_SYSCALL 0x050f0000000fc0c7ULL
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#else
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#define RT_SIGRETURN_SYSCALL 0x050f40000201c0c7ULL
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#endif
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if (*(unsigned char *)(pc+0) == 0x48
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&& *(unsigned long long *)(pc+1) == RT_SIGRETURN_SYSCALL)
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{
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ucontext_t *uc_ = context->cfa;
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/* The void * cast is necessary to avoid an aliasing warning.
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The aliasing warning is correct, but should not be a problem
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because it does not alias anything. */
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sc = (struct sigcontext *) (void *) &uc_->uc_mcontext;
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}
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else
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return _URC_END_OF_STACK;
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new_cfa = sc->rsp;
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fs->regs.cfa_how = CFA_REG_OFFSET;
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/* Register 7 is rsp */
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fs->regs.cfa_reg = 7;
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fs->regs.cfa_offset = new_cfa - (long) context->cfa;
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/* The SVR4 register numbering macros aren't usable in libgcc. */
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fs->regs.reg[0].how = REG_SAVED_OFFSET;
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fs->regs.reg[0].loc.offset = (long)&sc->rax - new_cfa;
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fs->regs.reg[1].how = REG_SAVED_OFFSET;
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fs->regs.reg[1].loc.offset = (long)&sc->rdx - new_cfa;
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fs->regs.reg[2].how = REG_SAVED_OFFSET;
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fs->regs.reg[2].loc.offset = (long)&sc->rcx - new_cfa;
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fs->regs.reg[3].how = REG_SAVED_OFFSET;
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fs->regs.reg[3].loc.offset = (long)&sc->rbx - new_cfa;
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fs->regs.reg[4].how = REG_SAVED_OFFSET;
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fs->regs.reg[4].loc.offset = (long)&sc->rsi - new_cfa;
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fs->regs.reg[5].how = REG_SAVED_OFFSET;
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fs->regs.reg[5].loc.offset = (long)&sc->rdi - new_cfa;
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fs->regs.reg[6].how = REG_SAVED_OFFSET;
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fs->regs.reg[6].loc.offset = (long)&sc->rbp - new_cfa;
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fs->regs.reg[8].how = REG_SAVED_OFFSET;
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fs->regs.reg[8].loc.offset = (long)&sc->r8 - new_cfa;
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fs->regs.reg[9].how = REG_SAVED_OFFSET;
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fs->regs.reg[9].loc.offset = (long)&sc->r9 - new_cfa;
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fs->regs.reg[10].how = REG_SAVED_OFFSET;
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fs->regs.reg[10].loc.offset = (long)&sc->r10 - new_cfa;
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fs->regs.reg[11].how = REG_SAVED_OFFSET;
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fs->regs.reg[11].loc.offset = (long)&sc->r11 - new_cfa;
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fs->regs.reg[12].how = REG_SAVED_OFFSET;
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fs->regs.reg[12].loc.offset = (long)&sc->r12 - new_cfa;
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fs->regs.reg[13].how = REG_SAVED_OFFSET;
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fs->regs.reg[13].loc.offset = (long)&sc->r13 - new_cfa;
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fs->regs.reg[14].how = REG_SAVED_OFFSET;
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fs->regs.reg[14].loc.offset = (long)&sc->r14 - new_cfa;
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fs->regs.reg[15].how = REG_SAVED_OFFSET;
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fs->regs.reg[15].loc.offset = (long)&sc->r15 - new_cfa;
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fs->regs.reg[16].how = REG_SAVED_OFFSET;
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fs->regs.reg[16].loc.offset = (long)&sc->rip - new_cfa;
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fs->retaddr_column = 16;
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fs->signal_frame = 1;
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return _URC_NO_REASON;
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}
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#else /* ifdef __x86_64__ */
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#define MD_FALLBACK_FRAME_STATE_FOR x86_fallback_frame_state
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static _Unwind_Reason_Code
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x86_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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unsigned char *pc = context->ra;
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struct sigcontext *sc;
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long new_cfa;
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/* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80 */
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if (*(unsigned short *)(pc+0) == 0xb858
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&& *(unsigned int *)(pc+2) == 119
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&& *(unsigned short *)(pc+6) == 0x80cd)
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sc = context->cfa + 4;
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/* movl $__NR_rt_sigreturn,%eax ; int $0x80 */
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else if (*(unsigned char *)(pc+0) == 0xb8
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&& *(unsigned int *)(pc+1) == 173
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&& *(unsigned short *)(pc+5) == 0x80cd)
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{
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struct rt_sigframe {
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int sig;
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siginfo_t *pinfo;
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void *puc;
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siginfo_t info;
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ucontext_t uc;
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} *rt_ = context->cfa;
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/* The void * cast is necessary to avoid an aliasing warning.
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The aliasing warning is correct, but should not be a problem
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because it does not alias anything. */
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sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
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}
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else
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return _URC_END_OF_STACK;
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new_cfa = sc->esp;
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fs->regs.cfa_how = CFA_REG_OFFSET;
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fs->regs.cfa_reg = 4;
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fs->regs.cfa_offset = new_cfa - (long) context->cfa;
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/* The SVR4 register numbering macros aren't usable in libgcc. */
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fs->regs.reg[0].how = REG_SAVED_OFFSET;
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fs->regs.reg[0].loc.offset = (long)&sc->eax - new_cfa;
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fs->regs.reg[3].how = REG_SAVED_OFFSET;
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fs->regs.reg[3].loc.offset = (long)&sc->ebx - new_cfa;
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fs->regs.reg[1].how = REG_SAVED_OFFSET;
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fs->regs.reg[1].loc.offset = (long)&sc->ecx - new_cfa;
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fs->regs.reg[2].how = REG_SAVED_OFFSET;
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fs->regs.reg[2].loc.offset = (long)&sc->edx - new_cfa;
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fs->regs.reg[6].how = REG_SAVED_OFFSET;
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fs->regs.reg[6].loc.offset = (long)&sc->esi - new_cfa;
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fs->regs.reg[7].how = REG_SAVED_OFFSET;
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fs->regs.reg[7].loc.offset = (long)&sc->edi - new_cfa;
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fs->regs.reg[5].how = REG_SAVED_OFFSET;
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fs->regs.reg[5].loc.offset = (long)&sc->ebp - new_cfa;
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fs->regs.reg[8].how = REG_SAVED_OFFSET;
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fs->regs.reg[8].loc.offset = (long)&sc->eip - new_cfa;
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fs->retaddr_column = 8;
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fs->signal_frame = 1;
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return _URC_NO_REASON;
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}
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#define MD_FROB_UPDATE_CONTEXT x86_frob_update_context
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/* Fix up for kernels that have vDSO, but don't have S flag in it. */
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static void
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x86_frob_update_context (struct _Unwind_Context *context,
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_Unwind_FrameState *fs ATTRIBUTE_UNUSED)
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{
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unsigned char *pc = context->ra;
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/* movl $__NR_rt_sigreturn,%eax ; {int $0x80 | syscall} */
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if (*(unsigned char *)(pc+0) == 0xb8
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&& *(unsigned int *)(pc+1) == 173
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&& (*(unsigned short *)(pc+5) == 0x80cd
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|| *(unsigned short *)(pc+5) == 0x050f))
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_Unwind_SetSignalFrame (context, 1);
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}
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#endif /* ifdef __x86_64__ */
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#endif /* not glibc 2.0 */
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#endif /* ifdef inhibit_libc */
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