libgcc/config/csky/linux-unwind.h

   1 /* DWARF2 EH unwinding support for C-SKY Linux.
   2    Copyright (C) 2018 Free Software Foundation, Inc.
   3    Contributed by C-SKY Microsystems and Mentor Graphics.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    GCC is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    Under Section 7 of GPL version 3, you are granted additional
  18    permissions described in the GCC Runtime Library Exception, version
  19    3.1, as published by the Free Software Foundation.
  20
  21    You should have received a copy of the GNU General Public License and
  22    a copy of the GCC Runtime Library Exception along with this program;
  23    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24    <http://www.gnu.org/licenses/>.  */
  25
  26 #ifndef inhibit_libc
  27
  28 /* Do code reading to identify a signal frame, and set the frame
  29    state data appropriately.  See unwind-dw2.c for the structs.  */
  30
  31 #include <signal.h>
  32 #include <asm/unistd.h>
  33
  34 /* The third parameter to the signal handler points to something with
  35    this structure defined in asm/ucontext.h, but the name clashes with
  36    struct ucontext from sys/ucontext.h so this private copy is used.  */
  37 typedef struct _sig_ucontext {
  38   unsigned long         uc_flags;
  39   struct _sig_ucontext  *uc_link;
  40   stack_t               uc_stack;
  41   struct sigcontext     uc_mcontext;
  42   sigset_t              uc_sigmask;
  43 } _sig_ucontext_t;
  44
  45 #define MD_FALLBACK_FRAME_STATE_FOR csky_fallback_frame_state
  46
  47 static _Unwind_Reason_Code
  48 csky_fallback_frame_state (struct _Unwind_Context *context,
  49                            _Unwind_FrameState *fs)
  50 {
  51   u_int16_t *pc = (u_int16_t *) context->ra;
  52   struct sigcontext *sc;
  53   _Unwind_Ptr new_cfa;
  54   int i;
  55
  56   /* movi r7, __NR_rt_sigreturn; trap 0  */
  57   if ((*(pc+0) == 0xea07) && (*(pc+1) == 119)
  58       && (*(pc+2) == 0xc000) &&  (*(pc+3) == 0x2020))
  59   {
  60     struct sigframe
  61     {
  62       int sig;
  63       int code;
  64       struct sigcontext *psc;
  65       unsigned long extramask[2]; /* _NSIG_WORDS */
  66       struct sigcontext sc;
  67     } *_rt = context->cfa;
  68     sc = _rt->psc; // &(_rt->sc);
  69   }
  70   /* movi r7, __NR_rt_sigreturn; trap 0  */
  71   else if ((*(pc+0) == 0xea07) && (*(pc+1) == 173)
  72            && (*(pc+2) == 0xc000) &&  (*(pc+3) == 0x2020))
  73   {
  74     struct rt_sigframe
  75     {
  76       int sig;
  77       struct siginfo *pinfo;
  78       void* puc;
  79       siginfo_t info;
  80       struct ucontext uc;
  81     } *_rt = context->cfa;
  82     sc = &(_rt->uc.uc_mcontext);
  83   }
  84   else
  85     return _URC_END_OF_STACK;
  86
  87   new_cfa = (_Unwind_Ptr) sc->sc_usp;
  88   fs->regs.cfa_how = CFA_REG_OFFSET;
  89   fs->regs.cfa_reg = STACK_POINTER_REGNUM;
  90   fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
  91
  92   fs->regs.reg[0].how = REG_SAVED_OFFSET;
  93   fs->regs.reg[0].loc.offset = (_Unwind_Ptr)&(sc->sc_a0) - new_cfa;
  94
  95   fs->regs.reg[1].how = REG_SAVED_OFFSET;
  96   fs->regs.reg[1].loc.offset = (_Unwind_Ptr)&(sc->sc_a1) - new_cfa;
  97
  98   fs->regs.reg[2].how = REG_SAVED_OFFSET;
  99   fs->regs.reg[2].loc.offset = (_Unwind_Ptr)&(sc->sc_a2) - new_cfa;
 100
 101   fs->regs.reg[3].how = REG_SAVED_OFFSET;
 102   fs->regs.reg[3].loc.offset = (_Unwind_Ptr)&(sc->sc_a3) - new_cfa;
 103
 104   for (i = 4; i < 14; i++)
 105     {
 106       fs->regs.reg[i].how = REG_SAVED_OFFSET;
 107       fs->regs.reg[i].loc.offset = ((_Unwind_Ptr)&(sc->sc_regs[i - 4])
 108                                     - new_cfa);
 109     }
 110
 111   for (i = 16; i < 32; i++)
 112     {
 113       fs->regs.reg[i].how = REG_SAVED_OFFSET;
 114       fs->regs.reg[i].loc.offset = ((_Unwind_Ptr)&(sc->sc_exregs[i - 16])
 115                                     - new_cfa);
 116     }
 117
 118   /* FIXME : hi lo ? */
 119   fs->regs.reg[15].how = REG_SAVED_OFFSET;
 120   fs->regs.reg[15].loc.offset = (_Unwind_Ptr)&(sc->sc_r15) - new_cfa;
 121
 122   fs->regs.reg[56].how = REG_SAVED_OFFSET;
 123   fs->regs.reg[56].loc.offset = (_Unwind_Ptr)&(sc->sc_pc) - new_cfa;
 124   fs->retaddr_column = 56;
 125   fs->signal_frame = 1;
 126
 127   return _URC_NO_REASON;
 128 }
 129
 130
 131 #endif