libgcc/config/arc/linux-unwind.h

   1 /* DWARF2 EH unwinding support for ARC Linux.
   2    Copyright (C) 2017-2018 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 it
   7    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, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  14    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
  21    and a copy of the GCC Runtime Library Exception along with this
  22    program; see the files COPYING3 and COPYING.RUNTIME respectively.
  23    If not, see <http://www.gnu.org/licenses/>.  */
  24
  25 /* This order is defined by a structure in the kernel, in file
  26    arch/arc/kernel/signal.c.  */
  27
  28 #define REGISTER_IN_STACK(REG_NAME, ID) \
  29   REG_NAME,
  30 enum registers_stack_order {
  31   REGISTER_STACK_ORDER_START = -1,
  32   #include "config/arc/linux-unwind-reg.def"
  33   REGISTER_STACK_ORDER_SIZE,
  34 };
  35
  36 struct register_position {
  37   int reg_id;
  38   int offset_in_stack;
  39 };
  40 #undef REGISTER_IN_STACK
  41
  42 #define REGISTER_SIZE_IN_WORDS 4
  43 #define REGISTER_IN_STACK(REG_NAME, ID) (int) ID,
  44 int
  45 register_id_for_index[REGISTER_STACK_ORDER_SIZE] = {
  46   #include "config/arc/linux-unwind-reg.def"
  47 };
  48 #undef REGISTER_IN_STACK
  49
  50 #ifndef inhibit_libc
  51 /* Do code reading to identify a signal frame, and set the frame
  52    state data appropriately.  See unwind-dw2.c for the structs.  */
  53
  54 #include <signal.h>
  55 #include <asm/unistd.h>
  56
  57 /*
  58 00010edc <__default_rt_sa_restorer>:
  59    10edc:       208a 12c2               mov     r8,139
  60    10ee0:       781e                    trap_s  0
  61    10ee2:       7ee0                    j_s     [blink]
  62 */
  63
  64 #if __BIG_ENDIAN__
  65 #define MOV_R8_139        0x8a20c212
  66 #define TRAP_S_J_S_BLINK  0x1e78e07e
  67 #define SWI               0x6f223f00
  68 #elif __LITTLE_ENDIAN__
  69 #define MOV_R8_139        0x12c2208a
  70 #define TRAP_S_J_S_BLINK  0x7ee0781e
  71 #define SWI               0x003f226f
  72 #endif
  73
  74 #define MD_FALLBACK_FRAME_STATE_FOR arc_fallback_frame_state
  75
  76 static __attribute__((noinline)) _Unwind_Reason_Code
  77 arc_fallback_frame_state (struct _Unwind_Context *context,
  78                            _Unwind_FrameState *fs)
  79 {
  80   struct rt_sigframe {
  81     siginfo_t info;
  82     ucontext_t uc;
  83     unsigned int sigret_magic;
  84   };
  85
  86   struct rt_sigframe *rt_;
  87   u_int32_t *pc = (u_int32_t *) context->ra;
  88   struct sigcontext *sc;
  89   _Unwind_Ptr new_cfa;
  90   int i;
  91
  92 #ifdef __ARC700__
  93   if (pc[1] != SWI)
  94     return _URC_END_OF_STACK;
  95 #else
  96   if (pc[1] != TRAP_S_J_S_BLINK)
  97     return _URC_END_OF_STACK;
  98 #endif
  99
 100   if (pc[0] == MOV_R8_139)
 101     {
 102       rt_ = context->cfa;
 103       sc = &rt_->uc.uc_mcontext;
 104     }
 105   else
 106     return _URC_END_OF_STACK;
 107
 108   new_cfa = (_Unwind_Ptr) sc;
 109   fs->regs.cfa_how = CFA_REG_OFFSET;
 110   fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
 111   fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
 112
 113   unsigned long *regs = &sc->regs.scratch.bta;
 114   for (i = 0; i < REGISTER_STACK_ORDER_SIZE; i++)
 115     {
 116       if (register_id_for_index[i] == -1)
 117         continue;
 118       fs->regs.reg[register_id_for_index[i]].how = REG_SAVED_OFFSET;
 119       fs->regs.reg[register_id_for_index[i]].loc.offset
 120         = ((_Unwind_Ptr) &(regs[i])) - new_cfa;
 121     }
 122
 123   fs->regs.reg[31].how = REG_SAVED_VAL_OFFSET;
 124   fs->regs.reg[31].loc.offset = ((_Unwind_Ptr) (regs[ret])) - new_cfa;
 125
 126   fs->retaddr_column = 31;
 127
 128   return _URC_NO_REASON;
 129 }
 130 #endif
 131
 132 #define MD_FROB_UPDATE_CONTEXT arc_frob_update_context
 133 /* Save fp register for unwinding to work.  */
 134
 135 static void
 136 arc_frob_update_context (struct _Unwind_Context *context,
 137                          _Unwind_FrameState *fs)
 138 {
 139   _Unwind_Word fp_val;
 140   asm ("mov %0,fp" : "=r" (fp_val));
 141
 142   switch (fs->regs.reg[27].how)
 143     {
 144     case REG_UNSAVED:
 145     case REG_UNDEFINED:
 146       if (context->reg[27] == NULL)
 147         _Unwind_SetGRValue (context, 27, fp_val);
 148       break;
 149
 150     default:
 151       break;
 152     }
 153 }