libgcc/config/sh/linux-unwind.h

   1 /* DWARF2 EH unwinding support for SH Linux.
   2    Copyright (C) 2004-2023 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
  26 /* Do code reading to identify a signal frame, and set the frame
  27    state data appropriately.  See unwind-dw2.c for the structs.
  28    Don't use this at all if inhibit_libc is used.  */
  29
  30 #ifndef inhibit_libc
  31
  32 #include <signal.h>
  33 #include <sys/ucontext.h>
  34 #include "insn-constants.h"
  35
  36 #define SH_DWARF_FRAME_GP0      0
  37 #define SH_DWARF_FRAME_FP0      25
  38 #define SH_DWARF_FRAME_XD0      87
  39 #define SH_DWARF_FRAME_PR       17
  40 #define SH_DWARF_FRAME_GBR      18
  41 #define SH_DWARF_FRAME_MACH     20
  42 #define SH_DWARF_FRAME_MACL     21
  43 #define SH_DWARF_FRAME_PC       16
  44 #define SH_DWARF_FRAME_SR       22
  45 #define SH_DWARF_FRAME_FPUL     23
  46 #define SH_DWARF_FRAME_FPSCR    24
  47
  48 #define MD_FALLBACK_FRAME_STATE_FOR sh_fallback_frame_state
  49
  50 static _Unwind_Reason_Code
  51 sh_fallback_frame_state (struct _Unwind_Context *context,
  52                          _Unwind_FrameState *fs)
  53 {
  54   unsigned char *pc = context->ra;
  55   struct sigcontext *sc;
  56   long new_cfa;
  57   int i;
  58 #if defined (__SH3E__) || defined (__SH4__)
  59   int r;
  60 #endif
  61
  62   /* mov.w 1f,r3; trapa #0x10; 1: .short 0x77  (sigreturn)  */
  63   /* mov.w 1f,r3; trapa #0x10; 1: .short 0xad  (rt_sigreturn)  */
  64   /* Newer kernel uses pad instructions to avoid an SH-4 core bug.  */
  65   /* mov.w 1f,r3; trapa #0x10; or r0,r0; or r0,r0; or r0,r0; or r0,r0;
  66      or r0,r0; 1: .short 0x77  (sigreturn)  */
  67   /* mov.w 1f,r3; trapa #0x10; or r0,r0; or r0,r0; or r0,r0; or r0,r0;
  68      or r0,r0; 1: .short 0xad  (rt_sigreturn)  */
  69   if (((*(unsigned short *) (pc+0)  == 0x9300)
  70        && (*(unsigned short *) (pc+2)  == 0xc310)
  71        && (*(unsigned short *) (pc+4)  == 0x0077))
  72       || (((*(unsigned short *) (pc+0)  == 0x9305)
  73            && (*(unsigned short *) (pc+2)  == 0xc310)
  74            && (*(unsigned short *) (pc+14)  == 0x0077))))
  75     sc = context->cfa;
  76   else if (((*(unsigned short *) (pc+0) == 0x9300)
  77             && (*(unsigned short *) (pc+2)  == 0xc310)
  78             && (*(unsigned short *) (pc+4)  == 0x00ad))
  79            || (((*(unsigned short *) (pc+0) == 0x9305)
  80                 && (*(unsigned short *) (pc+2)  == 0xc310)
  81                 && (*(unsigned short *) (pc+14)  == 0x00ad))))
  82     {
  83       struct rt_sigframe {
  84         siginfo_t info;
  85         ucontext_t uc;
  86       } *rt_ = context->cfa;
  87       /* The void * cast is necessary to avoid an aliasing warning.
  88          The aliasing warning is correct, but should not be a problem
  89          because it does not alias anything.  */
  90       sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
  91     }
  92   else
  93     return _URC_END_OF_STACK;
  94
  95   new_cfa = sc->sc_regs[15];
  96   fs->regs.cfa_how = CFA_REG_OFFSET;
  97   fs->regs.cfa_reg = 15;
  98   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
  99
 100   for (i = 0; i < 15; i++)
 101     {
 102       fs->regs.how[i] = REG_SAVED_OFFSET;
 103       fs->regs.reg[i].loc.offset
 104         = (long)&(sc->sc_regs[i]) - new_cfa;
 105     }
 106
 107   fs->regs.how[SH_DWARF_FRAME_PR] = REG_SAVED_OFFSET;
 108   fs->regs.reg[SH_DWARF_FRAME_PR].loc.offset
 109     = (long)&(sc->sc_pr) - new_cfa;
 110   fs->regs.how[SH_DWARF_FRAME_SR] = REG_SAVED_OFFSET;
 111   fs->regs.reg[SH_DWARF_FRAME_SR].loc.offset
 112     = (long)&(sc->sc_sr) - new_cfa;
 113   fs->regs.how[SH_DWARF_FRAME_GBR] = REG_SAVED_OFFSET;
 114   fs->regs.reg[SH_DWARF_FRAME_GBR].loc.offset
 115     = (long)&(sc->sc_gbr) - new_cfa;
 116   fs->regs.how[SH_DWARF_FRAME_MACH] = REG_SAVED_OFFSET;
 117   fs->regs.reg[SH_DWARF_FRAME_MACH].loc.offset
 118     = (long)&(sc->sc_mach) - new_cfa;
 119   fs->regs.how[SH_DWARF_FRAME_MACL] = REG_SAVED_OFFSET;
 120   fs->regs.reg[SH_DWARF_FRAME_MACL].loc.offset
 121     = (long)&(sc->sc_macl) - new_cfa;
 122
 123 #if defined (__SH3E__) || defined (__SH4__)
 124   r = SH_DWARF_FRAME_FP0;
 125   for (i = 0; i < 16; i++)
 126     {
 127       fs->regs.how[r+i] = REG_SAVED_OFFSET;
 128       fs->regs.reg[r+i].loc.offset
 129         = (long)&(sc->sc_fpregs[i]) - new_cfa;
 130     }
 131
 132   r = SH_DWARF_FRAME_XD0;
 133   for (i = 0; i < 8; i++)
 134     {
 135       fs->regs.how[r+i] = REG_SAVED_OFFSET;
 136       fs->regs.reg[r+i].loc.offset
 137         = (long)&(sc->sc_xfpregs[2*i]) - new_cfa;
 138     }
 139
 140   fs->regs.how[SH_DWARF_FRAME_FPUL] = REG_SAVED_OFFSET;
 141   fs->regs.reg[SH_DWARF_FRAME_FPUL].loc.offset
 142     = (long)&(sc->sc_fpul) - new_cfa;
 143   fs->regs.how[SH_DWARF_FRAME_FPSCR] = REG_SAVED_OFFSET;
 144   fs->regs.reg[SH_DWARF_FRAME_FPSCR].loc.offset
 145     = (long)&(sc->sc_fpscr) - new_cfa;
 146 #endif
 147
 148   fs->regs.how[SH_DWARF_FRAME_PC] = REG_SAVED_OFFSET;
 149   fs->regs.reg[SH_DWARF_FRAME_PC].loc.offset
 150     = (long)&(sc->sc_pc) - new_cfa;
 151   fs->retaddr_column = SH_DWARF_FRAME_PC;
 152   fs->signal_frame = 1;
 153   return _URC_NO_REASON;
 154 }
 155
 156 #endif /* inhibit_libc */