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/* DWARF2 EH unwinding support for SPARC Solaris.

   Copyright (C) 2009 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>

#if defined(__arch64__)

#define MD_FALLBACK_FRAME_STATE_FOR sparc64_fallback_frame_state

static _Unwind_Reason_Code

sparc64_fallback_frame_state (struct _Unwind_Context *context,

                              _Unwind_FrameState *fs)

{

  void *pc = context->ra;

  void *this_cfa = context->cfa;

  void *new_cfa, *ra_location, *shifted_ra_location;

  int regs_off;

  int fpu_save_off;

  unsigned char fpu_save;

  int i;

  /* This is the observed pattern for the sigacthandler in Solaris 8.  */

  unsigned int sigacthandler_sol8_pattern []

    = {0x9401400f, 0xca5aafa0, 0x913e2000, 0x892a3003,

       0xe0590005, 0x9fc40000, 0x9410001a, 0x80a6e008};

  /* This is the observed pattern for the sigacthandler in Solaris 9.  */

  unsigned int sigacthandler_sol9_pattern []

    = {0xa33e2000, 0x00000000, 0x892c7003, 0x90100011,

       0xe0590005, 0x9fc40000, 0x9410001a, 0x80a46008};

  /* This is the observed pattern for the __sighndlr.  */

  unsigned int sighndlr_pattern []

    = {0x9de3bf50, 0x90100018, 0x92100019, 0x9fc6c000,

       0x9410001a, 0x81c7e008, 0x81e80000};

  /* 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;

    }

  /* Look for the sigacthandler pattern.  The pattern changes slightly

     in different versions of the operating system, so we skip the

     comparison against pc-(4*6) for Solaris 9.  */

  if ((    *(unsigned int *)(pc-(4*7)) == sigacthandler_sol8_pattern[0]

        && *(unsigned int *)(pc-(4*6)) == sigacthandler_sol8_pattern[1]

        && *(unsigned int *)(pc-(4*5)) == sigacthandler_sol8_pattern[2]

        && *(unsigned int *)(pc-(4*4)) == sigacthandler_sol8_pattern[3]

        && *(unsigned int *)(pc-(4*3)) == sigacthandler_sol8_pattern[4]

        && *(unsigned int *)(pc-(4*2)) == sigacthandler_sol8_pattern[5]

        && *(unsigned int *)(pc-(4*1)) == sigacthandler_sol8_pattern[6]

        && *(unsigned int *)(pc-(4*0)) == sigacthandler_sol8_pattern[7] ) ||

      (    *(unsigned int *)(pc-(4*7)) == sigacthandler_sol9_pattern[0]

        /* skip pc-(4*6) */

        && *(unsigned int *)(pc-(4*5)) == sigacthandler_sol9_pattern[2]

        && *(unsigned int *)(pc-(4*4)) == sigacthandler_sol9_pattern[3]

        && *(unsigned int *)(pc-(4*3)) == sigacthandler_sol9_pattern[4]

        && *(unsigned int *)(pc-(4*2)) == sigacthandler_sol9_pattern[5]

        && *(unsigned int *)(pc-(4*1)) == sigacthandler_sol9_pattern[6]

        && *(unsigned int *)(pc-(4*0)) == sigacthandler_sol9_pattern[7] ) )

    /* We need to move up two frames (the kernel frame and the handler

       frame).  Minimum stack frame size is 176 bytes (128 + 48): 128

       bytes for spilling register window (16 extended words for in

       and local registers), and 6 extended words to store at least

       6 arguments to callees, The kernel frame and the sigacthandler

       both have this minimal stack.  The ucontext_t structure is after

       this offset.  */

    regs_off = 176 + 176;

  /* Look for the __sighndlr pattern.  */

  else if (    *(unsigned int *)(pc-(4*5)) == sighndlr_pattern[0]

            && *(unsigned int *)(pc-(4*4)) == sighndlr_pattern[1]

            && *(unsigned int *)(pc-(4*3)) == sighndlr_pattern[2]

            && *(unsigned int *)(pc-(4*2)) == sighndlr_pattern[3]

            && *(unsigned int *)(pc-(4*1)) == sighndlr_pattern[4]

            && *(unsigned int *)(pc-(4*0)) == sighndlr_pattern[5]

            && *(unsigned int *)(pc+(4*1)) == sighndlr_pattern[6] )

    {

      /* We have observed different calling frames among different

         versions of the operating system, so that we need to

         discriminate using the upper frame.  We look for the return

         address of the caller frame (there is an offset of 15 double

         words between the frame address and the place where this return

         address is stored) in order to do some more pattern matching.  */

      unsigned int cuh_pattern

        = *(unsigned int *)(*(unsigned long *)(this_cfa + 15*8) - 4);

      if (cuh_pattern == 0x9410001a || cuh_pattern == 0x94100013)

        /* This matches the call_user_handler pattern for Solaris 9 and

           for Solaris 8 running inside Solaris Containers respectively.

           We need to move up four frames (the kernel frame, the signal

           frame, the call_user_handler frame, the __sighndlr frame).

           Three of them have the minimum stack frame size (kernel,

           signal, and __sighndlr frames) of 176 bytes, and there is

           another with a stack frame of 304 bytes (the call_user_handler

           frame).  The ucontext_t structure is after this offset.  */

        regs_off = 176 + 176 + 176 + 304;

      else

        /* We need to move up three frames (the kernel frame, the

           sigacthandler frame, and the __sighndlr frame).  The kernel

           frame has a stack frame size of 176, the __sighndlr frames of

           304 bytes, and there is a stack frame of 176 bytes for the

           sigacthandler frame.  The ucontext_t structure is after this

           offset.  */

        regs_off = 176 + 304 + 176;

    }

  /* Exit if the pattern at the return address does not match the

     previous three patterns.  */

  else

    return _URC_END_OF_STACK;

  /* FPU information can be extracted from the ucontext_t structure

     that is the third argument for the signal handler, that is saved

     in the stack.  There are 64 bytes between the beginning of the

     ucontext_t argument of the signal handler and the uc_mcontext

     field.  There are 176 bytes between the beginning of uc_mcontext

     and the beginning of the fpregs field.  */

  fpu_save_off = regs_off + (8*10) + 176;

  /* The fpregs field contains 32 extended words at the beginning that

     contain the fpu state.  Then there are 2 extended words and two

     bytes.  */

  fpu_save = *(unsigned char *)(this_cfa + fpu_save_off + (8*32) + (2*8) + 2);

  /* We need to get the frame pointer for the kernel frame that

     executes when the signal is raised.  This frame is just the

     following to the application code that generated the signal, so

     that the later's stack pointer is the former's frame pointer.

     The stack pointer for the interrupted application code can be

     calculated from the ucontext_t structure (third argument for the

     signal handler) that is saved in the stack.  There are 10 words

     between the beginning of the  ucontext_t argument  of the signal

     handler and the uc_mcontext.gregs field that contains the

     registers saved by the signal handler.  */

  new_cfa = *(void **)(this_cfa + regs_off + (8*10) + (REG_SP*8));

  /* The frame address is %sp + STACK_BIAS in 64-bit mode. */

  new_cfa += 2047;

  fs->regs.cfa_how = CFA_REG_OFFSET;

  fs->regs.cfa_reg = __builtin_dwarf_sp_column ();

  fs->regs.cfa_offset = new_cfa - 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

        = this_cfa + regs_off + (8*10) + ((REG_Y+i)*8) - 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*8;

    }

  /* Check whether we need to restore fpu registers.  */

  if (fpu_save)

    {

      for (i = 0; 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

            = this_cfa + fpu_save_off + (i*4) - new_cfa;

        }

    }

  /* 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 = this_cfa + regs_off + (8*10) + (REG_PC*8);

  shifted_ra_location = this_cfa + regs_off + (8*10) + (REG_Y*8);

  *(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 = shifted_ra_location - new_cfa;

  fs->signal_frame = 1;

  return _URC_NO_REASON;

}

#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)

    context->cfa -= 2047;

}

#else

#define MD_FALLBACK_FRAME_STATE_FOR sparc_fallback_frame_state

static _Unwind_Reason_Code

sparc_fallback_frame_state (struct _Unwind_Context *context,

                            _Unwind_FrameState *fs)

{

  void *pc = context->ra;

  void *this_cfa = context->cfa;

  void *new_cfa, *ra_location, *shifted_ra_location;

  int regs_off;

  int fpu_save_off;

  unsigned char fpu_save;

  int i;

  /* This is the observed pattern for the sigacthandler.  */

  unsigned int sigacthandler_pattern []

    = {0x9602400f, 0x92100019, 0x00000000, 0x912e2002,

       0xe002000a, 0x90100018, 0x9fc40000, 0x9410001a,

       0x80a62008};

  /* This is the observed pattern for the __libthread_segvhdlr.  */

  unsigned int segvhdlr_pattern []

    = {0x94102000, 0xe007bfe4, 0x9010001c, 0x92100019,

       0x9fc40000, 0x9410001a, 0x81c7e008, 0x81e80000,

       0x80a26000};

  /* This is the observed pattern for the __sighndlr.  */

  unsigned int sighndlr_pattern []

    = {0x9de3bfa0, 0x90100018, 0x92100019, 0x9fc6c000,

       0x9410001a, 0x81c7e008, 0x81e80000};

  /* 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;

    }

  /* Look for the sigacthandler pattern.  The pattern changes slightly

     in different versions of the operating system, so we skip the

     comparison against pc-(4*6).  */

  if (    *(unsigned int *)(pc-(4*8)) == sigacthandler_pattern[0]

       && *(unsigned int *)(pc-(4*7)) == sigacthandler_pattern[1]

       /* skip pc-(4*6) */

       && *(unsigned int *)(pc-(4*5)) == sigacthandler_pattern[3]

       && *(unsigned int *)(pc-(4*4)) == sigacthandler_pattern[4]

       && *(unsigned int *)(pc-(4*3)) == sigacthandler_pattern[5]

       && *(unsigned int *)(pc-(4*2)) == sigacthandler_pattern[6]

       && *(unsigned int *)(pc-(4*1)) == sigacthandler_pattern[7]

       && *(unsigned int *)(pc-(4*0)) == sigacthandler_pattern[8] )

    /* We need to move up two frames (the kernel frame and the handler

       frame).  Minimum stack frame size is 96 bytes (64 + 4 + 24): 64

       bytes for spilling register window (16 words for in and local

       registers), 4 bytes for a pointer to space for callees

       returning structs, and 24 bytes to store at least six argument

       to callees.  The ucontext_t structure is after this offset.  */

    regs_off = 96 + 96;

  /* Look for the __libthread_segvhdlr pattern.  */

  else if (    *(unsigned int *)(pc-(4*6)) == segvhdlr_pattern[0]

            && *(unsigned int *)(pc-(4*5)) == segvhdlr_pattern[1]

            && *(unsigned int *)(pc-(4*4)) == segvhdlr_pattern[2]

            && *(unsigned int *)(pc-(4*3)) == segvhdlr_pattern[3]

            && *(unsigned int *)(pc-(4*2)) == segvhdlr_pattern[4]

            && *(unsigned int *)(pc-(4*1)) == segvhdlr_pattern[5]

            && *(unsigned int *)(pc-(4*0)) == segvhdlr_pattern[6]

            && *(unsigned int *)(pc+(4*1)) == segvhdlr_pattern[7]

            && *(unsigned int *)(pc+(4*2)) == segvhdlr_pattern[8] )

    /* We need to move up four frames (the kernel frame, the

       sigacthandler frame, the __sighndlr frame, and the

       __libthread_segvhdlr).  Two of them have the minimum

       stack frame size (kernel and __sighndlr frames) of 96 bytes,

       other has a stack frame of 216 bytes (the sigacthandler frame),

       and there is another with a stack frame of 128 bytes (the

       __libthread_segvhdlr).  The ucontext_t structure is after this

       offset.  */

    regs_off = 96 + 96 + 128 + 216;

  /* Look for the __sighndlr pattern.  */

  else if (    *(unsigned int *)(pc-(4*5)) == sighndlr_pattern[0]

            && *(unsigned int *)(pc-(4*4)) == sighndlr_pattern[1]

            && *(unsigned int *)(pc-(4*3)) == sighndlr_pattern[2]

            && *(unsigned int *)(pc-(4*2)) == sighndlr_pattern[3]

            && *(unsigned int *)(pc-(4*1)) == sighndlr_pattern[4]

            && *(unsigned int *)(pc-(4*0)) == sighndlr_pattern[5]

            && *(unsigned int *)(pc+(4*1)) == sighndlr_pattern[6] )

    {

      /* We have observed different calling frames among different

         versions of the operating system, so that we need to

         discriminate using the upper frame.  We look for the return

         address of the caller frame (there is an offset of 15 words

         between the frame address and the place where this return

         address is stored) in order to do some more pattern matching.  */

      unsigned int cuh_pattern

        = *(unsigned int *)(*(unsigned int *)(this_cfa + 15*4) - 4);

      if (cuh_pattern == 0xd407a04c)

        /* This matches the call_user_handler pattern for Solaris 10.

           We need to move up three frames (the kernel frame, the

           call_user_handler frame, the __sighndlr frame).  Two of them

           have the minimum stack frame size (kernel and __sighndlr

           frames) of 96 bytes, and there is another with a stack frame

           of 160 bytes (the call_user_handler frame).  The ucontext_t

          structure is after this offset.  */

        regs_off = 96 + 96 + 160;

      else if (cuh_pattern == 0x9410001a || cuh_pattern == 0x9410001b)

        /* This matches the call_user_handler pattern for Solaris 9 and

           for Solaris 8 running inside Solaris Containers respectively.

           We need to move up four frames (the kernel frame, the signal

           frame, the call_user_handler frame, the __sighndlr frame).

           Three of them have the minimum stack frame size (kernel,

           signal, and __sighndlr frames) of 96 bytes, and there is

           another with a stack frame of 160 bytes (the call_user_handler

           frame).  The ucontext_t structure is after this offset.  */

        regs_off = 96 + 96 + 96 + 160;

      else

        /* We need to move up three frames (the kernel frame, the

           sigacthandler frame, and the __sighndlr frame).  Two of them

           have the minimum stack frame size (kernel and __sighndlr

           frames) of 96 bytes, and there is another with a stack frame

           of 216 bytes (the sigacthandler frame).  The ucontext_t

           structure is after this offset.  */

        regs_off = 96 + 96 + 216;

    }

  /* Exit if the pattern at the return address does not match the

     previous three patterns.  */

  else

    return _URC_END_OF_STACK;

  /* FPU information can be extracted from the ucontext_t structure

     that is the third argument for the signal handler, that is saved

     in the stack.  There are 10 words between the beginning of the

     ucontext_t argument of the signal handler and the uc_mcontext

     field.  There are 80 bytes between the beginning of uc_mcontext

     and the beginning of the fpregs field.  */

  fpu_save_off = regs_off + (4*10) + (4*20);

  /* The fpregs field contains 32 words at the beginning that contain

     the fpu state.  Then there are 2 words and two bytes.  */

  fpu_save = *(unsigned char *)(this_cfa + fpu_save_off + (4*32) + (2*4) + 2);

  /* We need to get the frame pointer for the kernel frame that

     executes when the signal is raised.  This frame is just the

     following to the application code that generated the signal, so

     that the later's stack pointer is the former's frame pointer.

     The stack pointer for the interrupted application code can be

     calculated from the ucontext_t structure (third argument for the

     signal handler) that is saved in the stack.  There are 10 words

     between the beginning of the  ucontext_t argument  of the signal

     handler and the uc_mcontext.gregs field that contains the

     registers saved by the signal handler.  */

  new_cfa = *(void **)(this_cfa + regs_off + (4*10) + (REG_SP*4));

  fs->regs.cfa_how = CFA_REG_OFFSET;

  fs->regs.cfa_reg = __builtin_dwarf_sp_column ();

  fs->regs.cfa_offset = new_cfa - 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

        = this_cfa + regs_off + (4*10) + ((REG_Y+i)*4) - new_cfa;

    }

  /* Just above the stack pointer there are 16 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*4;

    }

  /* Check whether we need to restore fpu registers.  */

  if (fpu_save)

    {

      for (i = 0; i < 32; i++)

        {

          fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;

          fs->regs.reg[i + 32].loc.offset

            = this_cfa + fpu_save_off + (i*4) - new_cfa;

        }

    }

  /* 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 = this_cfa + regs_off + (4*10) + (REG_PC*4);

  shifted_ra_location = this_cfa + regs_off + (4*10) + (REG_Y*4);

  *(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 = shifted_ra_location - new_cfa;

  fs->signal_frame = 1;

  return _URC_NO_REASON;

};

#endif