xref: /freebsd-10-stable/contrib/gcc/config/i386/linux-unwind.h

/* DWARF2 EH unwinding support for AMD x86-64 and x86.
   Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.

This file is part of GCC.

GCC 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, or (at your option)
any later version.

In addition to the permissions in the GNU General Public License, the
Free Software Foundation gives you unlimited permission to link the
compiled version of this file with other programs, and to distribute
those programs without any restriction coming from the use of this
file.  (The General Public License restrictions do apply in other
respects; for example, they cover modification of the file, and
distribution when not linked into another program.)

GCC 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 GCC; see the file COPYING.  If not, write to
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

/* Do code reading to identify a signal frame, and set the frame
   state data appropriately.  See unwind-dw2.c for the structs.
   Don't use this at all if inhibit_libc is used.  */

#ifndef inhibit_libc

#ifdef __x86_64__

#include <signal.h>
#include <sys/ucontext.h>

#define MD_FALLBACK_FRAME_STATE_FOR x86_64_fallback_frame_state

static _Unwind_Reason_Code
x86_64_fallback_frame_state (struct _Unwind_Context *context,
			     _Unwind_FrameState *fs)
{
  unsigned char *pc = context->ra;
  struct sigcontext *sc;
  long new_cfa;

  /* movq __NR_rt_sigreturn, %rax ; syscall  */
  if (*(unsigned char *)(pc+0) == 0x48
      && *(unsigned long *)(pc+1) == 0x050f0000000fc0c7)
    {
      struct ucontext *uc_ = context->cfa;
      /* The void * cast is necessary to avoid an aliasing warning.
         The aliasing warning is correct, but should not be a problem
         because it does not alias anything.  */
      sc = (struct sigcontext *) (void *) &uc_->uc_mcontext;
    }
  else
    return _URC_END_OF_STACK;

  new_cfa = sc->rsp;
  fs->cfa_how = CFA_REG_OFFSET;
  /* Register 7 is rsp  */
  fs->cfa_reg = 7;
  fs->cfa_offset = new_cfa - (long) context->cfa;

  /* The SVR4 register numbering macros aren't usable in libgcc.  */
  fs->regs.reg[0].how = REG_SAVED_OFFSET;
  fs->regs.reg[0].loc.offset = (long)&sc->rax - new_cfa;
  fs->regs.reg[1].how = REG_SAVED_OFFSET;
  fs->regs.reg[1].loc.offset = (long)&sc->rdx - new_cfa;
  fs->regs.reg[2].how = REG_SAVED_OFFSET;
  fs->regs.reg[2].loc.offset = (long)&sc->rcx - new_cfa;
  fs->regs.reg[3].how = REG_SAVED_OFFSET;
  fs->regs.reg[3].loc.offset = (long)&sc->rbx - new_cfa;
  fs->regs.reg[4].how = REG_SAVED_OFFSET;
  fs->regs.reg[4].loc.offset = (long)&sc->rsi - new_cfa;
  fs->regs.reg[5].how = REG_SAVED_OFFSET;
  fs->regs.reg[5].loc.offset = (long)&sc->rdi - new_cfa;
  fs->regs.reg[6].how = REG_SAVED_OFFSET;
  fs->regs.reg[6].loc.offset = (long)&sc->rbp - new_cfa;
  fs->regs.reg[8].how = REG_SAVED_OFFSET;
  fs->regs.reg[8].loc.offset = (long)&sc->r8 - new_cfa;
  fs->regs.reg[9].how = REG_SAVED_OFFSET;
  fs->regs.reg[9].loc.offset = (long)&sc->r9 - new_cfa;
  fs->regs.reg[10].how = REG_SAVED_OFFSET;
  fs->regs.reg[10].loc.offset = (long)&sc->r10 - new_cfa;
  fs->regs.reg[11].how = REG_SAVED_OFFSET;
  fs->regs.reg[11].loc.offset = (long)&sc->r11 - new_cfa;
  fs->regs.reg[12].how = REG_SAVED_OFFSET;
  fs->regs.reg[12].loc.offset = (long)&sc->r12 - new_cfa;
  fs->regs.reg[13].how = REG_SAVED_OFFSET;
  fs->regs.reg[13].loc.offset = (long)&sc->r13 - new_cfa;
  fs->regs.reg[14].how = REG_SAVED_OFFSET;
  fs->regs.reg[14].loc.offset = (long)&sc->r14 - new_cfa;
  fs->regs.reg[15].how = REG_SAVED_OFFSET;
  fs->regs.reg[15].loc.offset = (long)&sc->r15 - new_cfa;
  fs->regs.reg[16].how = REG_SAVED_OFFSET;
  fs->regs.reg[16].loc.offset = (long)&sc->rip - new_cfa;
  fs->retaddr_column = 16;
  fs->signal_frame = 1;
  return _URC_NO_REASON;
}

#else /* ifdef __x86_64__  */

/* There's no sys/ucontext.h for glibc 2.0, so no
   signal-turned-exceptions for them.  There's also no configure-run for
   the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H.  Using the
   target libc version macro should be enough.  */
#if !(__GLIBC__ == 2 && __GLIBC_MINOR__ == 0)

#include <signal.h>
#include <sys/ucontext.h>

#define MD_FALLBACK_FRAME_STATE_FOR x86_fallback_frame_state

static _Unwind_Reason_Code
x86_fallback_frame_state (struct _Unwind_Context *context,
			  _Unwind_FrameState *fs)
{
  unsigned char *pc = context->ra;
  struct sigcontext *sc;
  long new_cfa;

  /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */
  if (*(unsigned short *)(pc+0) == 0xb858
      && *(unsigned int *)(pc+2) == 119
      && *(unsigned short *)(pc+6) == 0x80cd)
    sc = context->cfa + 4;
  /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */
  else if (*(unsigned char *)(pc+0) == 0xb8
	   && *(unsigned int *)(pc+1) == 173
	   && *(unsigned short *)(pc+5) == 0x80cd)
    {
      struct rt_sigframe {
	int sig;
	struct siginfo *pinfo;
	void *puc;
	struct siginfo info;
	struct ucontext uc;
      } *rt_ = context->cfa;
      /* The void * cast is necessary to avoid an aliasing warning.
         The aliasing warning is correct, but should not be a problem
         because it does not alias anything.  */
      sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
    }
  else
    return _URC_END_OF_STACK;

  new_cfa = sc->REG_NAME(esp);
  fs->cfa_how = CFA_REG_OFFSET;
  fs->cfa_reg = 4;
  fs->cfa_offset = new_cfa - (long) context->cfa;

  /* The SVR4 register numbering macros aren't usable in libgcc.  */
  fs->regs.reg[0].how = REG_SAVED_OFFSET;
  fs->regs.reg[0].loc.offset = (long)&sc->REG_NAME(eax) - new_cfa;
  fs->regs.reg[3].how = REG_SAVED_OFFSET;
  fs->regs.reg[3].loc.offset = (long)&sc->REG_NAME(ebx) - new_cfa;
  fs->regs.reg[1].how = REG_SAVED_OFFSET;
  fs->regs.reg[1].loc.offset = (long)&sc->REG_NAME(ecx) - new_cfa;
  fs->regs.reg[2].how = REG_SAVED_OFFSET;
  fs->regs.reg[2].loc.offset = (long)&sc->REG_NAME(edx) - new_cfa;
  fs->regs.reg[6].how = REG_SAVED_OFFSET;
  fs->regs.reg[6].loc.offset = (long)&sc->REG_NAME(esi) - new_cfa;
  fs->regs.reg[7].how = REG_SAVED_OFFSET;
  fs->regs.reg[7].loc.offset = (long)&sc->REG_NAME(edi) - new_cfa;
  fs->regs.reg[5].how = REG_SAVED_OFFSET;
  fs->regs.reg[5].loc.offset = (long)&sc->REG_NAME(ebp) - new_cfa;
  fs->regs.reg[8].how = REG_SAVED_OFFSET;
  fs->regs.reg[8].loc.offset = (long)&sc->REG_NAME(eip) - new_cfa;
  fs->retaddr_column = 8;
  fs->signal_frame = 1;
  return _URC_NO_REASON;
}
#endif /* not glibc 2.0 */
#endif /* ifdef __x86_64__  */
#endif /* ifdef inhibit_libc  */