/* DWARF2 EH unwinding support for SH Linux.
   Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

In addition to the permissions in the GNU General Public License, the
Free Software Foundation gives you unlimited permission to link the
compiled version of this file with other programs, and to distribute
those programs without any restriction coming from the use of this
file.  (The General Public License restrictions do apply in other
respects; for example, they cover modification of the file, and
distribution when not linked into another program.)

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; see the file COPYING.  If not, write to
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

/* Do code reading to identify a signal frame, and set the frame
   state data appropriately.  See unwind-dw2.c for the structs.  */

#include <signal.h>
#include <sys/ucontext.h>
#include "insn-constants.h"

# if defined (__SH5__)
#define SH_DWARF_FRAME_GP0	0
#define SH_DWARF_FRAME_FP0	77
#define SH_DWARF_FRAME_BT0	68
#define SH_DWARF_FRAME_PR_MEDIA	18
#define SH_DWARF_FRAME_SR	65
#define SH_DWARF_FRAME_FPSCR	76
#else
#define SH_DWARF_FRAME_GP0	0
#define SH_DWARF_FRAME_FP0	25
#define SH_DWARF_FRAME_XD0	87
#define SH_DWARF_FRAME_PR	17
#define SH_DWARF_FRAME_GBR	19
#define SH_DWARF_FRAME_MACH	20
#define SH_DWARF_FRAME_MACL	21
#define SH_DWARF_FRAME_PC	16
#define SH_DWARF_FRAME_SR	22
#define SH_DWARF_FRAME_FPUL	23
#define SH_DWARF_FRAME_FPSCR	24
#endif /* defined (__SH5__) */

#if defined (__SH5__)

#define MD_FALLBACK_FRAME_STATE_FOR shmedia_fallback_frame_state

static _Unwind_Reason_Code
shmedia_fallback_frame_state (struct _Unwind_Context *context,
			      _Unwind_FrameState *fs)
{
  unsigned char *pc = context->ra;
  struct sigcontext *sc;
  long new_cfa;
  int i, r;

  /* movi 0x10,r9; shori 0x77,r9; trapa	r9; nop (sigreturn)  */
  /* movi 0x10,r9; shori 0xad,r9; trapa	r9; nop (rt_sigreturn)  */
  if ((*(unsigned long *) (pc-1)  == 0xcc004090)
      && (*(unsigned long *) (pc+3)  == 0xc801dc90)
      && (*(unsigned long *) (pc+7)  == 0x6c91fff0)
      && (*(unsigned long *) (pc+11)  == 0x6ff0fff0))
    sc = context->cfa;
  else if ((*(unsigned long *) (pc-1)  == 0xcc004090)
	   && (*(unsigned long *) (pc+3)  == 0xc802b490)
	   && (*(unsigned long *) (pc+7)  == 0x6c91fff0)
	   && (*(unsigned long *) (pc+11)  == 0x6ff0fff0))
    {
      struct rt_sigframe {
	struct siginfo *pinfo;
	void *puc;
	struct siginfo info;
	struct ucontext uc;
      } *rt_ = context->cfa;
      /* The void * cast is necessary to avoid an aliasing warning.
         The aliasing warning is correct, but should not be a problem
         because it does not alias anything.  */
      sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
    }
  else
    return _URC_END_OF_STACK;

  new_cfa = sc->sc_regs[15];
  fs->cfa_how = CFA_REG_OFFSET;
  fs->cfa_reg = 15;
  fs->cfa_offset = new_cfa - (long) context->cfa;

  for (i = 0; i < 63; i++)
    {
      if (i == 15)
	continue;

      fs->regs.reg[i].how = REG_SAVED_OFFSET;
      fs->regs.reg[i].loc.offset
	= (long)&(sc->sc_regs[i]) - new_cfa;
    }

  fs->regs.reg[SH_DWARF_FRAME_SR].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_SR].loc.offset
    = (long)&(sc->sc_sr) - new_cfa;

  r = SH_DWARF_FRAME_BT0;
  for (i = 0; i < 8; i++)
    {
      fs->regs.reg[r+i].how = REG_SAVED_OFFSET;
      fs->regs.reg[r+i].loc.offset
	= (long)&(sc->sc_tregs[i]) - new_cfa;
    }

  r = SH_DWARF_FRAME_FP0;
  for (i = 0; i < 32; i++)
    {
      fs->regs.reg[r+i].how = REG_SAVED_OFFSET;
      fs->regs.reg[r+i].loc.offset
	= (long)&(sc->sc_fpregs[i]) - new_cfa;
    }

  fs->regs.reg[SH_DWARF_FRAME_FPSCR].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_FPSCR].loc.offset
    = (long)&(sc->sc_fpscr) - new_cfa;

  /* We use the slot for the zero register to save return address.  */
  fs->regs.reg[63].how = REG_SAVED_OFFSET;
  fs->regs.reg[63].loc.offset
    = (long)&(sc->sc_pc) - new_cfa;
  fs->retaddr_column = 63;
  fs->signal_frame = 1;
  return _URC_NO_REASON;
}

#else /* defined (__SH5__) */

#define MD_FALLBACK_FRAME_STATE_FOR sh_fallback_frame_state

static _Unwind_Reason_Code
sh_fallback_frame_state (struct _Unwind_Context *context,
			 _Unwind_FrameState *fs)
{
  unsigned char *pc = context->ra;
  struct sigcontext *sc;
  long new_cfa;
  int i;
#if defined (__SH3E__) || defined (__SH4__)
  int r;
#endif

  /* mov.w 1f,r3; trapa #0x10; 1: .short 0x77  (sigreturn)  */
  /* mov.w 1f,r3; trapa #0x10; 1: .short 0xad  (rt_sigreturn)  */
  /* Newer kernel uses pad instructions to avoid an SH-4 core bug.  */
  /* mov.w 1f,r3; trapa #0x10; or r0,r0; or r0,r0; or r0,r0; or r0,r0;
     or r0,r0; 1: .short 0x77  (sigreturn)  */
  /* mov.w 1f,r3; trapa #0x10; or r0,r0; or r0,r0; or r0,r0; or r0,r0;
     or r0,r0; 1: .short 0xad  (rt_sigreturn)  */
  if (((*(unsigned short *) (pc+0)  == 0x9300)
       && (*(unsigned short *) (pc+2)  == 0xc310)
       && (*(unsigned short *) (pc+4)  == 0x0077))
      || (((*(unsigned short *) (pc+0)  == 0x9305)
	   && (*(unsigned short *) (pc+2)  == 0xc310)
	   && (*(unsigned short *) (pc+14)  == 0x0077))))
    sc = context->cfa;
  else if (((*(unsigned short *) (pc+0) == 0x9300)
	    && (*(unsigned short *) (pc+2)  == 0xc310)
	    && (*(unsigned short *) (pc+4)  == 0x00ad))
	   || (((*(unsigned short *) (pc+0) == 0x9305)
		&& (*(unsigned short *) (pc+2)  == 0xc310)
		&& (*(unsigned short *) (pc+14)  == 0x00ad))))
    {
      struct rt_sigframe {
	struct siginfo info;
	struct ucontext uc;
      } *rt_ = context->cfa;
      /* The void * cast is necessary to avoid an aliasing warning.
         The aliasing warning is correct, but should not be a problem
         because it does not alias anything.  */
      sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
    }
  else
    return _URC_END_OF_STACK;

  new_cfa = sc->sc_regs[15];
  fs->cfa_how = CFA_REG_OFFSET;
  fs->cfa_reg = 15;
  fs->cfa_offset = new_cfa - (long) context->cfa;

  for (i = 0; i < 15; i++)
    {
      fs->regs.reg[i].how = REG_SAVED_OFFSET;
      fs->regs.reg[i].loc.offset
	= (long)&(sc->sc_regs[i]) - new_cfa;
    }

  fs->regs.reg[SH_DWARF_FRAME_PR].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_PR].loc.offset
    = (long)&(sc->sc_pr) - new_cfa;
  fs->regs.reg[SH_DWARF_FRAME_SR].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_SR].loc.offset
    = (long)&(sc->sc_sr) - new_cfa;
  fs->regs.reg[SH_DWARF_FRAME_GBR].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_GBR].loc.offset
    = (long)&(sc->sc_gbr) - new_cfa;
  fs->regs.reg[SH_DWARF_FRAME_MACH].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_MACH].loc.offset
    = (long)&(sc->sc_mach) - new_cfa;
  fs->regs.reg[SH_DWARF_FRAME_MACL].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_MACL].loc.offset
    = (long)&(sc->sc_macl) - new_cfa;

#if defined (__SH3E__) || defined (__SH4__)
  r = SH_DWARF_FRAME_FP0;
  for (i = 0; i < 16; i++)
    {
      fs->regs.reg[r+i].how = REG_SAVED_OFFSET;
      fs->regs.reg[r+i].loc.offset
	= (long)&(sc->sc_fpregs[i]) - new_cfa;
    }

  r = SH_DWARF_FRAME_XD0;
  for (i = 0; i < 8; i++)
    {
      fs->regs.reg[i].how = REG_SAVED_OFFSET;
      fs->regs.reg[i].loc.offset
	= (long)&(sc->sc_xfpregs[2*i]) - new_cfa;
    }

  fs->regs.reg[SH_DWARF_FRAME_FPUL].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_FPUL].loc.offset
    = (long)&(sc->sc_fpul) - new_cfa;
  fs->regs.reg[SH_DWARF_FRAME_FPSCR].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_FPSCR].loc.offset
    = (long)&(sc->sc_fpscr) - new_cfa;
#endif

  fs->regs.reg[SH_DWARF_FRAME_PC].how = REG_SAVED_OFFSET;
  fs->regs.reg[SH_DWARF_FRAME_PC].loc.offset
    = (long)&(sc->sc_pc) - new_cfa;
  fs->retaddr_column = SH_DWARF_FRAME_PC;
  fs->signal_frame = 1;
  return _URC_NO_REASON;
}
#endif /* defined (__SH5__) */