libgcc/config/m68k/linux-unwind.h

   1 /* DWARF2 EH unwinding support for Linux/m68k.
   2    Copyright (C) 2006-2013 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 #include <signal.h>
  32
  33 /* <sys/ucontext.h> is unfortunately broken right now.  */
  34 struct uw_ucontext {
  35         unsigned long     uc_flags;
  36         struct ucontext  *uc_link;
  37         stack_t           uc_stack;
  38         mcontext_t        uc_mcontext;
  39         unsigned long     uc_filler[80];
  40         __sigset_t        uc_sigmask;
  41 };
  42
  43 #define MD_FALLBACK_FRAME_STATE_FOR m68k_fallback_frame_state
  44
  45 #ifdef __mcoldfire__
  46 #define M68K_FP_SIZE  8
  47 #else
  48 #define M68K_FP_SIZE  12
  49 #endif
  50
  51 static _Unwind_Reason_Code
  52 m68k_fallback_frame_state (struct _Unwind_Context *context,
  53                            _Unwind_FrameState *fs)
  54 {
  55   unsigned short *pc = context->ra;
  56   long cfa;
  57
  58   /* moveq #__NR_sigreturn,%d0; trap #0  */
  59   if (pc[0] == 0x7077 && pc[1] == 0x4e40)
  60     {
  61       struct sigcontext *sc;
  62
  63       /* Context is passed as the 3rd argument.  */
  64       sc = *(struct sigcontext **) (context->cfa + 8);
  65
  66       cfa = sc->sc_usp;
  67       fs->regs.cfa_how = CFA_REG_OFFSET;
  68       fs->regs.cfa_reg = 15;
  69       fs->regs.cfa_offset = cfa - (long) context->cfa;
  70
  71       fs->regs.reg[0].how = REG_SAVED_OFFSET;
  72       fs->regs.reg[0].loc.offset = (long) &sc->sc_d0 - cfa;
  73       fs->regs.reg[1].how = REG_SAVED_OFFSET;
  74       fs->regs.reg[1].loc.offset = (long) &sc->sc_d1 - cfa;
  75       fs->regs.reg[8].how = REG_SAVED_OFFSET;
  76       fs->regs.reg[8].loc.offset = (long) &sc->sc_a0 - cfa;
  77       fs->regs.reg[9].how = REG_SAVED_OFFSET;
  78       fs->regs.reg[9].loc.offset = (long) &sc->sc_a1 - cfa;
  79
  80 #ifdef __uClinux__
  81       fs->regs.reg[13].how = REG_SAVED_OFFSET;
  82       fs->regs.reg[13].loc.offset = (long) &sc->sc_a5 - cfa;
  83 #endif
  84
  85       fs->regs.reg[24].how = REG_SAVED_OFFSET;
  86       fs->regs.reg[24].loc.offset = (long) &sc->sc_pc - cfa;
  87
  88 #ifndef __uClinux__
  89       if (*(int *) sc->sc_fpstate)
  90         {
  91           int *fpregs = (int *) sc->sc_fpregs;
  92
  93           fs->regs.reg[16].how = REG_SAVED_OFFSET;
  94           fs->regs.reg[16].loc.offset = (long) &fpregs[0] - cfa;
  95           fs->regs.reg[17].how = REG_SAVED_OFFSET;
  96           fs->regs.reg[17].loc.offset = (long) &fpregs[M68K_FP_SIZE/4] - cfa;
  97         }
  98 #elif defined __mcffpu__
  99 # error Implement this when uClinux kernel is ported to an FPU architecture
 100 #endif
 101     }
 102 #ifdef __mcoldfire__
 103   /* move.l #__NR_rt_sigreturn,%d0; trap #0 */
 104   else if (pc[0] == 0x203c && pc[1] == 0x0000 &&
 105            pc[2] == 0x00ad && pc[3] == 0x4e40)
 106 #else
 107   /* moveq #~__NR_rt_sigreturn,%d0; not.b %d0; trap #0 */
 108   else if (pc[0] == 0x7052 && pc[1] == 0x4600 && pc[2] == 0x4e40)
 109 #endif
 110     {
 111       struct uw_ucontext *uc;
 112       greg_t *gregs;
 113       int i;
 114
 115       /* Context is passed as the 3rd argument.  */
 116       uc = *(struct uw_ucontext **) (context->cfa + 8);
 117
 118       gregs = uc->uc_mcontext.gregs;
 119       cfa = gregs[15];
 120       fs->regs.cfa_how = CFA_REG_OFFSET;
 121       fs->regs.cfa_reg = 15;
 122       fs->regs.cfa_offset = cfa - (long) context->cfa;
 123
 124       /* register %d0-%d7/%a0-%a6  */
 125       for (i = 0; i <= 14; i++)
 126         {
 127           fs->regs.reg[i].how = REG_SAVED_OFFSET;
 128           fs->regs.reg[i].loc.offset = (long) &gregs[i] - cfa;
 129         }
 130
 131       /* return address  */
 132       fs->regs.reg[24].how = REG_SAVED_OFFSET;
 133       fs->regs.reg[24].loc.offset = (long) &gregs[16] - cfa;
 134
 135 #define uc_fpstate      uc_filler[0]
 136
 137       if (uc->uc_fpstate)
 138         {
 139           long fpregs = (long) uc->uc_mcontext.fpregs.f_fpregs;
 140
 141           /* register %fp0-%fp7  */
 142           for (i = 16; i <= 23; i++)
 143             {
 144               fs->regs.reg[i].how = REG_SAVED_OFFSET;
 145               fs->regs.reg[i].loc.offset = fpregs - cfa;
 146               fpregs += M68K_FP_SIZE;
 147             }
 148         }
 149     }
 150   else
 151     return _URC_END_OF_STACK;
 152
 153   fs->retaddr_column = 24;
 154   fs->signal_frame = 1;
 155
 156   return _URC_NO_REASON;
 157 }
 158 #endif /* ifdef inhibit_libc  */