/* DWARF2 EH unwinding support for SPARC Solaris.
   Copyright (C) 2009, 2010, 2011 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 3, or (at your option)
any later version.

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.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

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

#include <ucontext.h>
#include <sys/frame.h>
#include <sys/stack.h>

#if defined(__arch64__)

#define IS_SIGHANDLER sparc64_is_sighandler

static int
sparc64_is_sighandler (unsigned int *pc, unsigned int *savpc, int *nframes)
{
  if (/* Solaris 8 - single-threaded
	----------------------------
	<sigacthandler+24>:  add  %g5, %o7, %o2
	<sigacthandler+28>:  ldx  [ %o2 + 0xfa0 ], %g5
	<sigacthandler+32>:  sra  %i0, 0, %o0
	<sigacthandler+36>:  sllx  %o0, 3, %g4
	<sigacthandler+40>:  ldx  [ %g4 + %g5 ], %l0
	<sigacthandler+44>:  call  %l0
	<sigacthandler+48>:  mov  %i2, %o2
	<sigacthandler+52>:  cmp  %i3, 8	<--- PC  */
      (   pc[-7] == 0x9401400f
       && pc[-6] == 0xca5aafa0
       && pc[-5] == 0x913e2000
       && pc[-4] == 0x892a3003
       && pc[-3] == 0xe0590005
       && pc[-2] == 0x9fc40000
       && pc[-1] == 0x9410001a
       && pc[ 0] == 0x80a6e008)

      || /* Solaris 9 - single-threaded
	   ----------------------------
	   The pattern changes slightly in different versions of the
	   operating system, so we skip the comparison against pc[-6] for
	   Solaris 9.

	   <sigacthandler+24>:  sra  %i0, 0, %l1

	   Solaris 9 5/02:
	   <sigacthandler+28>:  ldx  [ %o2 + 0xf68 ], %g5
	   Solaris 9 9/05:
	   <sigacthandler+28>:  ldx  [ %o2 + 0xe50 ], %g5

	   <sigacthandler+32>:  sllx  %l1, 3, %g4
	   <sigacthandler+36>:  mov  %l1, %o0
	   <sigacthandler+40>:  ldx  [ %g4 + %g5 ], %l0
	   <sigacthandler+44>:  call  %l0
	   <sigacthandler+48>:  mov  %i2, %o2
	   <sigacthandler+52>:  cmp  %l1, 8	<--- PC  */
      (   pc[-7] == 0xa33e2000
       /* skip pc[-6] */
       && pc[-5] == 0x892c7003
       && pc[-4] == 0x90100011
       && pc[-3] == 0xe0590005
       && pc[-2] == 0x9fc40000
       && pc[-1] == 0x9410001a
       && pc[ 0] == 0x80a46008))
    {
      /* We need to move up one frame:

		<signal handler>	<-- context->cfa
		sigacthandler
		<kernel>
      */
      *nframes = 1;
      return 1;
    }

  if (/* Solaris 8+ - multi-threaded
	----------------------------
	<__sighndlr>:        save  %sp, -176, %sp
	<__sighndlr+4>:      mov  %i0, %o0
	<__sighndlr+8>:      mov  %i1, %o1
	<__sighndlr+12>:     call  %i3
	<__sighndlr+16>:     mov  %i2, %o2
	<__sighndlr+20>:     ret 		<--- PC
	<__sighndlr+24>:     restore  */
         pc[-5] == 0x9de3bf50
      && pc[-4] == 0x90100018
      && pc[-3] == 0x92100019
      && pc[-2] == 0x9fc6c000
      && pc[-1] == 0x9410001a
      && pc[ 0] == 0x81c7e008
      && pc[ 1] == 0x81e80000)
    {
      if (/* Solaris 8 /usr/lib/sparcv9/libthread.so.1
	    ------------------------------------------
	    Before patch 108827-08:
	    <sigacthandler+1760>:     st  %g4, [ %i1 + 0x1c ]

	    Since patch 108827-08:
	    <sigacthandler+1816>:     st  %l0, [ %i4 + 0x10 ]  */
	        savpc[-1] == 0xc826601c
	     || savpc[-1] == 0xe0272010)
	{
	  /* We need to move up three frames:

		<signal handler>	<-- context->cfa
		__sighndlr
		sigacthandler
		<kernel>
	  */
	  *nframes = 2;
	}
      else /* Solaris 8 /usr/lib/lwp/sparcv9/libthread.so.1, Solaris 9+
	     ----------------------------------------------------------  */
	{
	  /* We need to move up three frames:

		<signal handler>	<-- context->cfa
		__sighndlr
		call_user_handler
		sigacthandler
		<kernel>
	  */
	  *nframes = 3;
	}
      return 1;
    }

  return 0;
}

#define MD_FALLBACK_FRAME_STATE_FOR sparc64_fallback_frame_state

#define MD_FROB_UPDATE_CONTEXT sparc64_frob_update_context

static void
sparc64_frob_update_context (struct _Unwind_Context *context,
			     _Unwind_FrameState *fs)
{
  /* The column of %sp contains the old CFA, not the old value of %sp.
     The CFA offset already comprises the stack bias so, when %sp is the
     CFA register, we must avoid counting the stack bias twice.  Do not
     do that for signal frames as the offset is artificial for them.  */
  if (fs->regs.cfa_reg == __builtin_dwarf_sp_column ()
      && fs->regs.cfa_how == CFA_REG_OFFSET
      && fs->regs.cfa_offset != 0
      && !fs->signal_frame)
    {
      long i;

      context->cfa -= STACK_BIAS;

      for (i = 0; i < DWARF_FRAME_REGISTERS + 1; ++i)
	if (fs->regs.reg[i].how == REG_SAVED_OFFSET)
	  _Unwind_SetGRPtr (context, i,
			    _Unwind_GetGRPtr (context, i) - STACK_BIAS);
    }
}

#else

#define IS_SIGHANDLER sparc_is_sighandler

static int
sparc_is_sighandler (unsigned int *pc, unsigned int * savpc, int *nframes)
{
  if (/* Solaris 8, 9 - single-threaded
        -------------------------------
	The pattern changes slightly in different versions of the operating
	system, so we skip the comparison against pc[-6].

	<sigacthandler+16>:  add  %o1, %o7, %o3
	<sigacthandler+20>:  mov  %i1, %o1

	<sigacthandler+24>:  ld  [ %o3 + <offset> ], %o2

	<sigacthandler+28>:  sll  %i0, 2, %o0
	<sigacthandler+32>:  ld  [ %o0 + %o2 ], %l0
	<sigacthandler+36>:  mov  %i0, %o0
	<sigacthandler+40>:  call  %l0
	<sigacthandler+44>:  mov  %i2, %o2
	<sigacthandler+48>:  cmp  %i0, 8	<--- PC  */
         pc[-8] == 0x9602400f
      && pc[-7] == 0x92100019
      /* skip pc[-6] */
      && pc[-5] == 0x912e2002
      && pc[-4] == 0xe002000a
      && pc[-3] == 0x90100018
      && pc[-2] == 0x9fc40000
      && pc[-1] == 0x9410001a
      && pc[ 0] == 0x80a62008)
    {
      /* Need to move up one frame:

		<signal handler>	<-- context->cfa
		sigacthandler
		<kernel>
      */
      *nframes = 1;
      return 1;
    }

  if (/* Solaris 8 - multi-threaded
	---------------------------
	<__libthread_segvhdlr+212>:  clr  %o2
	<__libthread_segvhdlr+216>:  ld  [ %fp + -28 ], %l0
	<__libthread_segvhdlr+220>:  mov  %i4, %o0
	<__libthread_segvhdlr+224>:  mov  %i1, %o1
	<__libthread_segvhdlr+228>:  call  %l0
	<__libthread_segvhdlr+232>:  mov  %i2, %o2
	<__libthread_segvhdlr+236>:  ret		<--- PC
	<__libthread_segvhdlr+240>:  restore
	<__libthread_segvhdlr+244>:  cmp  %o1, 0  */
         pc[-6] == 0x94102000
      && pc[-5] == 0xe007bfe4
      && pc[-4] == 0x9010001c
      && pc[-3] == 0x92100019
      && pc[-2] == 0x9fc40000
      && pc[-1] == 0x9410001a
      && pc[ 0] == 0x81c7e008
      && pc[ 1] == 0x81e80000
      && pc[ 2] == 0x80a26000)
    {
      /* Need to move up one frame:

		<signal handler>	<-- context->cfa
		__libthread_segvhdlr
		<kernel>
      */
      *nframes = 1;
      return 1;
    }

  if(/* Solaris 8+ - multi-threaded
       ----------------------------
       <__sighndlr>:	save  %sp, -96, %sp
       <__sighndlr+4>:	mov  %i0, %o0
       <__sighndlr+8>:	mov  %i1, %o1
       <__sighndlr+12>:	call  %i3
       <__sighndlr+16>:	mov  %i2, %o2
       <__sighndlr+20>:	ret 		<--- PC
       <__sighndlr+24>:	restore  */
        pc[-5] == 0x9de3bfa0
     && pc[-4] == 0x90100018
     && pc[-3] == 0x92100019
     && pc[-2] == 0x9fc6c000
     && pc[-1] == 0x9410001a
     && pc[ 0] == 0x81c7e008
     && pc[ 1] == 0x81e80000)
    {
      if (/* Solaris 8 /usr/lib/libthread.so.1
	    ----------------------------------
	    <sigacthandler+1796>:     mov  %i0, %o0  */
	  savpc[-1] == 0x90100018)
	{
	  /* We need to move up two frames:

		<signal handler>	<-- context->cfa
		__sighndlr
		sigacthandler
		<kernel>
	  */
	  *nframes = 2;
	}
      else /* Solaris 8 /usr/lib/lwp/libthread.so.1, Solaris 9+
	     --------------------------------------------------  */
	{
	  /* We need to move up three frames:

		<signal handler>	<-- context->cfa
		__sighndlr
		call_user_handler
		sigacthandler
		<kernel>
	  */
	  *nframes = 3;
	}
      return 1;
    }

  return 0;
}

#define MD_FALLBACK_FRAME_STATE_FOR sparc_fallback_frame_state

#endif

static _Unwind_Reason_Code
MD_FALLBACK_FRAME_STATE_FOR (struct _Unwind_Context *context,
			     _Unwind_FrameState *fs)
{
  void *pc = context->ra;
  struct frame *fp = (struct frame *) context->cfa;
  int nframes;
  void *this_cfa = context->cfa;
  long new_cfa;
  void *ra_location, *shifted_ra_location;
  mcontext_t *mctx;
  int i;

  /* Deal with frame-less function from which a signal was raised.  */
  if (_Unwind_IsSignalFrame (context))
    {
      /* The CFA is by definition unmodified in this case.  */
      fs->regs.cfa_how = CFA_REG_OFFSET;
      fs->regs.cfa_reg = __builtin_dwarf_sp_column ();
      fs->regs.cfa_offset = 0;

      /* This is the canonical RA column.  */
      fs->retaddr_column = 15;

      return _URC_NO_REASON;
    }

  if (IS_SIGHANDLER (pc, (unsigned int *)fp->fr_savpc, &nframes))
    {
      struct handler_args {
	struct frame frwin;
	ucontext_t ucontext;
      } *handler_args;
      ucontext_t *ucp;

      /* context->cfa points into the frame after the saved frame pointer and
         saved pc (struct frame).

         The ucontext_t structure is in the kernel frame after a struct
         frame.  Since the frame sizes vary even within OS releases, we
         need to walk the stack to get there.  */

      for (i = 0; i < nframes; i++)
	fp = (struct frame *) ((char *)fp->fr_savfp + STACK_BIAS);

      handler_args = (struct handler_args *) fp;
      ucp = &handler_args->ucontext;
      mctx = &ucp->uc_mcontext;
    }

  /* Exit if the pattern at the return address does not match the
     previous three patterns.  */
  else
    return _URC_END_OF_STACK;

  new_cfa = mctx->gregs[REG_SP];
  /* The frame address is %sp + STACK_BIAS in 64-bit mode.  */
  new_cfa += STACK_BIAS;

  fs->regs.cfa_how = CFA_REG_OFFSET;
  fs->regs.cfa_reg = __builtin_dwarf_sp_column ();
  fs->regs.cfa_offset = new_cfa - (long) this_cfa;

  /* Restore global and out registers (in this order) from the
     ucontext_t structure, uc_mcontext.gregs field.  */
  for (i = 1; i < 16; i++)
    {
      /* We never restore %sp as everything is purely CFA-based.  */
      if ((unsigned int) i == __builtin_dwarf_sp_column ())
	continue;

      /* First the global registers and then the out registers.  */
      fs->regs.reg[i].how = REG_SAVED_OFFSET;
      fs->regs.reg[i].loc.offset = (long)&mctx->gregs[REG_Y + i] - new_cfa;
    }

  /* Just above the stack pointer there are 16 extended words in which
     the register window (in and local registers) was saved.  */
  for (i = 0; i < 16; i++)
    {
      fs->regs.reg[i + 16].how = REG_SAVED_OFFSET;
      fs->regs.reg[i + 16].loc.offset = i*sizeof(long);
    }

  /* Check whether we need to restore FPU registers.  */
  if (mctx->fpregs.fpu_qcnt)
    {
      for (i = 0; i < 32; i++)
	{
	  fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
	  fs->regs.reg[i + 32].loc.offset
	    = (long)&mctx->fpregs.fpu_fr.fpu_regs[i] - new_cfa;
	}

#ifdef __arch64__
      /* For 64-bit, fpu_fr.fpu_dregs contains 32 instead of 16 doubles.  */
      for (i = 32; i < 64; i++)
	{
	  if (i > 32 && (i & 1))
	    continue;

	  fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
	  fs->regs.reg[i + 32].loc.offset
	    = (long)&mctx->fpregs.fpu_fr.fpu_dregs[i/2] - new_cfa;
	}
#endif
    }

  /* State the rules to find the kernel's code "return address", which is
     the address of the active instruction when the signal was caught.
     On the SPARC, since RETURN_ADDR_OFFSET (essentially 8) is defined, we
     need to preventively subtract it from the purported return address.  */
  ra_location = &mctx->gregs[REG_PC];
  shifted_ra_location = &mctx->gregs[REG_Y];
  *(void **)shifted_ra_location = *(void **)ra_location - 8;
  fs->retaddr_column = 0;
  fs->regs.reg[0].how = REG_SAVED_OFFSET;
  fs->regs.reg[0].loc.offset = (long)shifted_ra_location - new_cfa;
  fs->signal_frame = 1;

  return _URC_NO_REASON;
}