libgcc/config/tilepro/linux-unwind.h

   1 /* DWARF2 EH unwinding support for TILEPro.
   2    Copyright (C) 2011-2018 Free Software Foundation, Inc.
   3    Contributed by Walter Lee (walt@tilera.com)
   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 #include <arch/abi.h>
  29 #include <signal.h>
  30 #include <sys/ucontext.h>
  31 #include <linux/unistd.h>
  32
  33 /* Macro to define a copy of the kernel's __rt_sigreturn function
  34    (in arch/tile/kernel/entry.S).  If that function is changed,
  35    this one needs to be changed to match it.  */
  36 #define _sigreturn_asm(REG, NR) asm(                    \
  37     ".pushsection .text.__rt_sigreturn,\"a\"\n"         \
  38     ".global __rt_sigreturn\n"                          \
  39     ".type __rt_sigreturn,@function\n"                  \
  40     "__rt_sigreturn:\n"                                 \
  41     "moveli " #REG ", " #NR "\n"                        \
  42     "swint1\n"                                          \
  43     ".size __rt_sigreturn, . - __rt_sigreturn\n"        \
  44     ".popsection")
  45 #define sigreturn_asm(REG, NR) _sigreturn_asm(REG, NR)
  46 sigreturn_asm (TREG_SYSCALL_NR_NAME, __NR_rt_sigreturn);
  47 #define SIGRETURN_LEN 16
  48 extern char __rt_sigreturn[];
  49
  50 #define MD_FALLBACK_FRAME_STATE_FOR tile_fallback_frame_state
  51
  52 static _Unwind_Reason_Code
  53 tile_fallback_frame_state (struct _Unwind_Context *context,
  54                               _Unwind_FrameState *fs)
  55 {
  56   unsigned char *pc = context->ra;
  57   struct sigcontext *sc;
  58   long new_cfa;
  59   int i;
  60
  61   struct rt_sigframe {
  62     unsigned char save_area[C_ABI_SAVE_AREA_SIZE];
  63     siginfo_t info;
  64     ucontext_t uc;
  65   } *rt_;
  66
  67   /* Return if this is not a signal handler.  */
  68   if (memcmp (pc, __rt_sigreturn, SIGRETURN_LEN) != 0)
  69     return _URC_END_OF_STACK;
  70
  71   /* It was a signal handler; update the reported PC to point to our
  72      copy, since that will be findable with dladdr() and therefore
  73      somewhat easier to help understand what actually happened. */
  74   context->ra = __rt_sigreturn;
  75
  76   rt_ = context->cfa;
  77   sc = &rt_->uc.uc_mcontext;
  78
  79   new_cfa = sc->sp;
  80   fs->regs.cfa_how = CFA_REG_OFFSET;
  81   fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
  82   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
  83
  84   for (i = 0; i < 56; ++i)
  85     {
  86       fs->regs.reg[i].how = REG_SAVED_OFFSET;
  87       fs->regs.reg[i].loc.offset
  88         = (long)&sc->gregs[i] - new_cfa;
  89     }
  90
  91   fs->regs.reg[56].how = REG_SAVED_OFFSET;
  92   fs->regs.reg[56].loc.offset = (long)&sc->pc - new_cfa;
  93   fs->retaddr_column = 56;
  94   fs->signal_frame = 1;
  95
  96   return _URC_NO_REASON;
  97 }
  98
  99 #endif /* ifdef inhibit_libc  */