gcc/config/mips/linux-unwind.h

   1 /* DWARF2 EH unwinding support for MIPS Linux.
   2    Copyright (C) 2004 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 2, 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 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #ifndef inhibit_libc
  22 /* Do code reading to identify a signal frame, and set the frame
  23    state data appropriately.  See unwind-dw2.c for the structs.  */
  24
  25 #include <signal.h>
  26
  27 /* The third parameter to the signal handler points to something with
  28  * this structure defined in asm/ucontext.h, but the name clashes with
  29  * struct ucontext from sys/ucontext.h so this private copy is used.  */
  30 typedef struct _sig_ucontext {
  31     unsigned long         uc_flags;
  32     struct _sig_ucontext  *uc_link;
  33     stack_t               uc_stack;
  34     struct sigcontext uc_mcontext;
  35     sigset_t      uc_sigmask;
  36 } _sig_ucontext_t;
  37
  38 #define MD_FALLBACK_FRAME_STATE_FOR mips_fallback_frame_state
  39
  40 static _Unwind_Reason_Code
  41 mips_fallback_frame_state (struct _Unwind_Context *context,
  42                            _Unwind_FrameState *fs)
  43 {
  44   u_int32_t *pc = (u_int32_t *) context->ra;
  45   struct sigcontext *sc;
  46   _Unwind_Ptr new_cfa;
  47   int i;
  48
  49   /* 24021061 li v0, 0x1061 (rt_sigreturn)*/
  50   /* 0000000c syscall    */
  51   /*    or */
  52   /* 24021017 li v0, 0x1017 (sigreturn) */
  53   /* 0000000c syscall  */
  54   if (*(pc + 1) != 0x0000000c)
  55     return _URC_END_OF_STACK;
  56   if (*(pc + 0) == 0x24021017)
  57     {
  58       struct sigframe {
  59         u_int32_t  trampoline[2];
  60         struct sigcontext sigctx;
  61       } *rt_ = context->ra;
  62       sc = &rt_->sigctx;
  63     }
  64   else if (*(pc + 0) == 0x24021061)
  65     {
  66       struct rt_sigframe {
  67         u_int32_t  trampoline[2];
  68         struct siginfo info;
  69         _sig_ucontext_t uc;
  70       } *rt_ = context->ra;
  71       sc = &rt_->uc.uc_mcontext;
  72     }
  73   else
  74     return _URC_END_OF_STACK;
  75
  76   new_cfa = (_Unwind_Ptr)sc;
  77   fs->cfa_how = CFA_REG_OFFSET;
  78   fs->cfa_reg = STACK_POINTER_REGNUM;
  79   fs->cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
  80
  81   for (i = 0; i < 32; i++) {
  82     fs->regs.reg[i].how = REG_SAVED_OFFSET;
  83     fs->regs.reg[i].loc.offset
  84       = (_Unwind_Ptr)&(sc->sc_regs[i]) - new_cfa;
  85   }
  86   fs->regs.reg[SIGNAL_UNWIND_RETURN_COLUMN].how = REG_SAVED_OFFSET;
  87   fs->regs.reg[SIGNAL_UNWIND_RETURN_COLUMN].loc.offset
  88     = (_Unwind_Ptr)&(sc->sc_pc) - new_cfa;
  89   fs->retaddr_column = SIGNAL_UNWIND_RETURN_COLUMN;
  90
  91   return _URC_NO_REASON;
  92 }
  93 #endif