gcc/config/i386/linux-unwind.h

   1 /* DWARF2 EH unwinding support for AMD x86-64 and x86.
   2    Copyright (C) 2004, 2005, 2006, 2009 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 /* Do code reading to identify a signal frame, and set the frame
  26    state data appropriately.  See unwind-dw2.c for the structs.
  27    Don't use this at all if inhibit_libc is used.  */
  28
  29 #ifndef inhibit_libc
  30
  31 #ifdef __x86_64__
  32
  33 #include <signal.h>
  34 #include <sys/ucontext.h>
  35
  36 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_fallback_frame_state
  37
  38 static _Unwind_Reason_Code
  39 x86_64_fallback_frame_state (struct _Unwind_Context *context,
  40                              _Unwind_FrameState *fs)
  41 {
  42   unsigned char *pc = context->ra;
  43   struct sigcontext *sc;
  44   long new_cfa;
  45
  46   /* movq __NR_rt_sigreturn, %rax ; syscall  */
  47   if (*(unsigned char *)(pc+0) == 0x48
  48       && *(unsigned long *)(pc+1) == 0x050f0000000fc0c7)
  49     {
  50       struct ucontext *uc_ = context->cfa;
  51       /* The void * cast is necessary to avoid an aliasing warning.
  52          The aliasing warning is correct, but should not be a problem
  53          because it does not alias anything.  */
  54       sc = (struct sigcontext *) (void *) &uc_->uc_mcontext;
  55     }
  56   else
  57     return _URC_END_OF_STACK;
  58
  59   new_cfa = sc->rsp;
  60   fs->regs.cfa_how = CFA_REG_OFFSET;
  61   /* Register 7 is rsp  */
  62   fs->regs.cfa_reg = 7;
  63   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
  64
  65   /* The SVR4 register numbering macros aren't usable in libgcc.  */
  66   fs->regs.reg[0].how = REG_SAVED_OFFSET;
  67   fs->regs.reg[0].loc.offset = (long)&sc->rax - new_cfa;
  68   fs->regs.reg[1].how = REG_SAVED_OFFSET;
  69   fs->regs.reg[1].loc.offset = (long)&sc->rdx - new_cfa;
  70   fs->regs.reg[2].how = REG_SAVED_OFFSET;
  71   fs->regs.reg[2].loc.offset = (long)&sc->rcx - new_cfa;
  72   fs->regs.reg[3].how = REG_SAVED_OFFSET;
  73   fs->regs.reg[3].loc.offset = (long)&sc->rbx - new_cfa;
  74   fs->regs.reg[4].how = REG_SAVED_OFFSET;
  75   fs->regs.reg[4].loc.offset = (long)&sc->rsi - new_cfa;
  76   fs->regs.reg[5].how = REG_SAVED_OFFSET;
  77   fs->regs.reg[5].loc.offset = (long)&sc->rdi - new_cfa;
  78   fs->regs.reg[6].how = REG_SAVED_OFFSET;
  79   fs->regs.reg[6].loc.offset = (long)&sc->rbp - new_cfa;
  80   fs->regs.reg[8].how = REG_SAVED_OFFSET;
  81   fs->regs.reg[8].loc.offset = (long)&sc->r8 - new_cfa;
  82   fs->regs.reg[9].how = REG_SAVED_OFFSET;
  83   fs->regs.reg[9].loc.offset = (long)&sc->r9 - new_cfa;
  84   fs->regs.reg[10].how = REG_SAVED_OFFSET;
  85   fs->regs.reg[10].loc.offset = (long)&sc->r10 - new_cfa;
  86   fs->regs.reg[11].how = REG_SAVED_OFFSET;
  87   fs->regs.reg[11].loc.offset = (long)&sc->r11 - new_cfa;
  88   fs->regs.reg[12].how = REG_SAVED_OFFSET;
  89   fs->regs.reg[12].loc.offset = (long)&sc->r12 - new_cfa;
  90   fs->regs.reg[13].how = REG_SAVED_OFFSET;
  91   fs->regs.reg[13].loc.offset = (long)&sc->r13 - new_cfa;
  92   fs->regs.reg[14].how = REG_SAVED_OFFSET;
  93   fs->regs.reg[14].loc.offset = (long)&sc->r14 - new_cfa;
  94   fs->regs.reg[15].how = REG_SAVED_OFFSET;
  95   fs->regs.reg[15].loc.offset = (long)&sc->r15 - new_cfa;
  96   fs->regs.reg[16].how = REG_SAVED_OFFSET;
  97   fs->regs.reg[16].loc.offset = (long)&sc->rip - new_cfa;
  98   fs->retaddr_column = 16;
  99   fs->signal_frame = 1;
 100   return _URC_NO_REASON;
 101 }
 102
 103 #else /* ifdef __x86_64__  */
 104
 105 /* There's no sys/ucontext.h for glibc 2.0, so no
 106    signal-turned-exceptions for them.  There's also no configure-run for
 107    the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H.  Using the
 108    target libc version macro should be enough.  */
 109 #if defined __GLIBC__ && !(__GLIBC__ == 2 && __GLIBC_MINOR__ == 0)
 110
 111 #include <signal.h>
 112 #include <sys/ucontext.h>
 113
 114 #define MD_FALLBACK_FRAME_STATE_FOR x86_fallback_frame_state
 115
 116 static _Unwind_Reason_Code
 117 x86_fallback_frame_state (struct _Unwind_Context *context,
 118                           _Unwind_FrameState *fs)
 119 {
 120   unsigned char *pc = context->ra;
 121   struct sigcontext *sc;
 122   long new_cfa;
 123
 124   /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */
 125   if (*(unsigned short *)(pc+0) == 0xb858
 126       && *(unsigned int *)(pc+2) == 119
 127       && *(unsigned short *)(pc+6) == 0x80cd)
 128     sc = context->cfa + 4;
 129   /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */
 130   else if (*(unsigned char *)(pc+0) == 0xb8
 131            && *(unsigned int *)(pc+1) == 173
 132            && *(unsigned short *)(pc+5) == 0x80cd)
 133     {
 134       struct rt_sigframe {
 135         int sig;
 136         struct siginfo *pinfo;
 137         void *puc;
 138         struct siginfo info;
 139         struct ucontext uc;
 140       } *rt_ = context->cfa;
 141       /* The void * cast is necessary to avoid an aliasing warning.
 142          The aliasing warning is correct, but should not be a problem
 143          because it does not alias anything.  */
 144       sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
 145     }
 146   else
 147     return _URC_END_OF_STACK;
 148
 149   new_cfa = sc->REG_NAME(esp);
 150   fs->regs.cfa_how = CFA_REG_OFFSET;
 151   fs->regs.cfa_reg = 4;
 152   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
 153
 154   /* The SVR4 register numbering macros aren't usable in libgcc.  */
 155   fs->regs.reg[0].how = REG_SAVED_OFFSET;
 156   fs->regs.reg[0].loc.offset = (long)&sc->REG_NAME(eax) - new_cfa;
 157   fs->regs.reg[3].how = REG_SAVED_OFFSET;
 158   fs->regs.reg[3].loc.offset = (long)&sc->REG_NAME(ebx) - new_cfa;
 159   fs->regs.reg[1].how = REG_SAVED_OFFSET;
 160   fs->regs.reg[1].loc.offset = (long)&sc->REG_NAME(ecx) - new_cfa;
 161   fs->regs.reg[2].how = REG_SAVED_OFFSET;
 162   fs->regs.reg[2].loc.offset = (long)&sc->REG_NAME(edx) - new_cfa;
 163   fs->regs.reg[6].how = REG_SAVED_OFFSET;
 164   fs->regs.reg[6].loc.offset = (long)&sc->REG_NAME(esi) - new_cfa;
 165   fs->regs.reg[7].how = REG_SAVED_OFFSET;
 166   fs->regs.reg[7].loc.offset = (long)&sc->REG_NAME(edi) - new_cfa;
 167   fs->regs.reg[5].how = REG_SAVED_OFFSET;
 168   fs->regs.reg[5].loc.offset = (long)&sc->REG_NAME(ebp) - new_cfa;
 169   fs->regs.reg[8].how = REG_SAVED_OFFSET;
 170   fs->regs.reg[8].loc.offset = (long)&sc->REG_NAME(eip) - new_cfa;
 171   fs->retaddr_column = 8;
 172   fs->signal_frame = 1;
 173   return _URC_NO_REASON;
 174 }
 175
 176 #define MD_FROB_UPDATE_CONTEXT x86_frob_update_context
 177
 178 /* Fix up for kernels that have vDSO, but don't have S flag in it.  */
 179
 180 static void
 181 x86_frob_update_context (struct _Unwind_Context *context,
 182                          _Unwind_FrameState *fs ATTRIBUTE_UNUSED)
 183 {
 184   unsigned char *pc = context->ra;
 185
 186   /* movl $__NR_rt_sigreturn,%eax ; {int $0x80 | syscall}  */
 187   if (*(unsigned char *)(pc+0) == 0xb8
 188       && *(unsigned int *)(pc+1) == 173
 189       && (*(unsigned short *)(pc+5) == 0x80cd
 190           || *(unsigned short *)(pc+5) == 0x050f))
 191     _Unwind_SetSignalFrame (context, 1);
 192 }
 193
 194 #endif /* not glibc 2.0 */
 195 #endif /* ifdef __x86_64__  */
 196 #endif /* ifdef inhibit_libc  */