Пример #1
0
int
xfer_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len, int write,
	     struct mem_attrib *attrib, struct target_ops *target)
{
  int res;
  const char *section_name = NULL;

  if (len <= 0)
    internal_error (__FILE__, __LINE__, _("failed internal consistency check"));

  if (overlay_debugging)
    {
      struct obj_section *section = find_pc_overlay (memaddr);

      if (section != NULL)
	{
	  if (pc_in_unmapped_range (memaddr, section))
	    memaddr = overlay_mapped_address (memaddr, section);
	  section_name = section->the_bfd_section->name;
	}
    }

  return section_table_xfer_memory (memaddr, myaddr, len, write,
				    target->to_sections,
				    target->to_sections_end,
				    section_name);
}
Пример #2
0
int
find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
			  CORE_ADDR *endaddr)
{
  asection *section;

  section = find_pc_overlay (pc);
  return find_pc_sect_partial_function (pc, section, name, address, endaddr);
}
Пример #3
0
int
find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
			  CORE_ADDR *endaddr)
{
  struct bfd_section *bfd_section;

  /* To ensure that the symbol returned belongs to the correct setion
     (and that the last [random] symbol from the previous section
     isn't returned) try to find the section containing PC.  First try
     the overlay code (which by default returns NULL); and second try
     the normal section code (which almost always succeeds).  */
  bfd_section = find_pc_overlay (pc);
  if (bfd_section == NULL)
    {
      struct obj_section *obj_section = find_pc_section (pc);
      if (obj_section == NULL)
	bfd_section = NULL;
      else
	bfd_section = obj_section->the_bfd_section;
    }
  return find_pc_sect_partial_function (pc, bfd_section, name, address,
					endaddr);
}
Пример #4
0
int
find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name,
				    CORE_ADDR *address, CORE_ADDR *endaddr,
				    int *is_gnu_ifunc_p)
{
  struct obj_section *section;
  struct symbol *f;
  struct minimal_symbol *msymbol;
  struct symtab *symtab = NULL;
  struct objfile *objfile;
  int i;
  CORE_ADDR mapped_pc;

  /* To ensure that the symbol returned belongs to the correct setion
     (and that the last [random] symbol from the previous section
     isn't returned) try to find the section containing PC.  First try
     the overlay code (which by default returns NULL); and second try
     the normal section code (which almost always succeeds).  */
  section = find_pc_overlay (pc);
  if (section == NULL)
    section = find_pc_section (pc);

  mapped_pc = overlay_mapped_address (pc, section);

  if (mapped_pc >= cache_pc_function_low
      && mapped_pc < cache_pc_function_high
      && section == cache_pc_function_section)
    goto return_cached_value;

  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
  ALL_OBJFILES (objfile)
  {
    if (objfile->sf)
      symtab = objfile->sf->qf->find_pc_sect_symtab (objfile, msymbol,
						     mapped_pc, section, 0);
    if (symtab)
      break;
  }

  if (symtab)
    {
      /* Checking whether the msymbol has a larger value is for the
	 "pathological" case mentioned in print_frame_info.  */
      f = find_pc_sect_function (mapped_pc, section);
      if (f != NULL
	  && (msymbol == NULL
	      || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
		  >= SYMBOL_VALUE_ADDRESS (msymbol))))
	{
	  cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
	  cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
	  cache_pc_function_name = SYMBOL_LINKAGE_NAME (f);
	  cache_pc_function_section = section;
	  cache_pc_function_is_gnu_ifunc = TYPE_GNU_IFUNC (SYMBOL_TYPE (f));
	  goto return_cached_value;
	}
    }

  /* Not in the normal symbol tables, see if the pc is in a known
     section.  If it's not, then give up.  This ensures that anything
     beyond the end of the text seg doesn't appear to be part of the
     last function in the text segment.  */

  if (!section)
    msymbol = NULL;

  /* Must be in the minimal symbol table.  */
  if (msymbol == NULL)
    {
      /* No available symbol.  */
      if (name != NULL)
	*name = 0;
      if (address != NULL)
	*address = 0;
      if (endaddr != NULL)
	*endaddr = 0;
      if (is_gnu_ifunc_p != NULL)
	*is_gnu_ifunc_p = 0;
      return 0;
    }

  cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
  cache_pc_function_name = SYMBOL_LINKAGE_NAME (msymbol);
  cache_pc_function_section = section;
  cache_pc_function_is_gnu_ifunc = MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc;

  /* If the minimal symbol has a size, use it for the cache.
     Otherwise use the lesser of the next minimal symbol in the same
     section, or the end of the section, as the end of the
     function.  */

  if (MSYMBOL_SIZE (msymbol) != 0)
    cache_pc_function_high = cache_pc_function_low + MSYMBOL_SIZE (msymbol);
  else
    {
      /* Step over other symbols at this same address, and symbols in
	 other sections, to find the next symbol in this section with
	 a different address.  */

      for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
	{
	  if (SYMBOL_VALUE_ADDRESS (msymbol + i)
	      != SYMBOL_VALUE_ADDRESS (msymbol)
	      && SYMBOL_OBJ_SECTION (msymbol + i)
	      == SYMBOL_OBJ_SECTION (msymbol))
	    break;
	}

      if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
	  && SYMBOL_VALUE_ADDRESS (msymbol + i)
	  < obj_section_endaddr (section))
	cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
      else
	/* We got the start address from the last msymbol in the objfile.
	   So the end address is the end of the section.  */
	cache_pc_function_high = obj_section_endaddr (section);
    }

 return_cached_value:

  if (address)
    {
      if (pc_in_unmapped_range (pc, section))
	*address = overlay_unmapped_address (cache_pc_function_low, section);
      else
	*address = cache_pc_function_low;
    }

  if (name)
    *name = cache_pc_function_name;

  if (endaddr)
    {
      if (pc_in_unmapped_range (pc, section))
	{
	  /* Because the high address is actually beyond the end of
	     the function (and therefore possibly beyond the end of
	     the overlay), we must actually convert (high - 1) and
	     then add one to that.  */

	  *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
						   section);
	}
      else
	*endaddr = cache_pc_function_high;
    }

  if (is_gnu_ifunc_p)
    *is_gnu_ifunc_p = cache_pc_function_is_gnu_ifunc;

  return 1;
}
Пример #5
0
static int
arm_linux_copy_svc (struct gdbarch *gdbarch, struct regcache *regs,
		    struct displaced_step_closure *dsc)
{
  CORE_ADDR return_to = 0;

  struct frame_info *frame;
  unsigned int svc_number = displaced_read_reg (regs, dsc, 7);
  int is_sigreturn = 0;
  int is_thumb;

  frame = get_current_frame ();

  is_sigreturn = arm_linux_sigreturn_return_addr(frame, svc_number,
						 &return_to, &is_thumb);
  if (is_sigreturn)
    {
	  struct symtab_and_line sal;

	  if (debug_displaced)
	    fprintf_unfiltered (gdb_stdlog, "displaced: found "
	      "sigreturn/rt_sigreturn SVC call.  PC in frame = %lx\n",
	      (unsigned long) get_frame_pc (frame));

	  if (debug_displaced)
	    fprintf_unfiltered (gdb_stdlog, "displaced: unwind pc = %lx.  "
	      "Setting momentary breakpoint.\n", (unsigned long) return_to);

	  gdb_assert (inferior_thread ()->control.step_resume_breakpoint
		      == NULL);

	  sal = find_pc_line (return_to, 0);
	  sal.pc = return_to;
	  sal.section = find_pc_overlay (return_to);
	  sal.explicit_pc = 1;

	  frame = get_prev_frame (frame);

	  if (frame)
	    {
	      inferior_thread ()->control.step_resume_breakpoint
        	= set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame),
					    bp_step_resume);

	      /* set_momentary_breakpoint invalidates FRAME.  */
	      frame = NULL;

	      /* We need to make sure we actually insert the momentary
	         breakpoint set above.  */
	      insert_breakpoints ();
	    }
	  else if (debug_displaced)
	    fprintf_unfiltered (gdb_stderr, "displaced: couldn't find previous "
				"frame to set momentary breakpoint for "
				"sigreturn/rt_sigreturn\n");
	}
      else if (debug_displaced)
	fprintf_unfiltered (gdb_stdlog, "displaced: sigreturn/rt_sigreturn "
			    "SVC call not in signal trampoline frame\n");
    

  /* Preparation: If we detect sigreturn, set momentary breakpoint at resume
		  location, else nothing.
     Insn: unmodified svc.
     Cleanup: if pc lands in scratch space, pc <- insn_addr + 4
              else leave pc alone.  */


  dsc->cleanup = &arm_linux_cleanup_svc;
  /* Pretend we wrote to the PC, so cleanup doesn't set PC to the next
     instruction.  */
  dsc->wrote_to_pc = 1;

  return 0;
}
Пример #6
0
static int
find_pc_partial_function_impl (CORE_ADDR pc, char **name, CORE_ADDR *address,
			       CORE_ADDR *endaddr, int inlining_flag)
{
  struct bfd_section *section;
  struct partial_symtab *pst;
  struct symbol *f;
  struct minimal_symbol *msymbol;
  struct partial_symbol *psb;
  struct obj_section *osect;
  int i;
  CORE_ADDR mapped_pc;

  /* To ensure that the symbol returned belongs to the correct setion
     (and that the last [random] symbol from the previous section
     isn't returned) try to find the section containing PC.  First try
     the overlay code (which by default returns NULL); and second try
     the normal section code (which almost always succeeds).  */
  section = find_pc_overlay (pc);
  if (section == NULL)
    {
      struct obj_section *obj_section = find_pc_section (pc);
      if (obj_section == NULL)
	section = NULL;
      else
	section = obj_section->the_bfd_section;
    }

  mapped_pc = overlay_mapped_address (pc, section);

  if (mapped_pc >= cache_pc_function_low
      && mapped_pc < cache_pc_function_high
      && section == cache_pc_function_section
      && inlining_flag == cache_pc_function_inlining)
    goto return_cached_value;

  cache_pc_function_inlining = inlining_flag;

  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
  pst = find_pc_sect_psymtab (mapped_pc, section);
  if (pst)
    {
      /* Need to read the symbols to get a good value for the end address.  */
      if (endaddr != NULL && !pst->readin)
	{
	  /* Need to get the terminal in case symbol-reading produces
	     output.  */
	  target_terminal_ours_for_output ();
	  PSYMTAB_TO_SYMTAB (pst);
	}

      if (pst->readin)
	{
	  /* Checking whether the msymbol has a larger value is for the
	     "pathological" case mentioned in print_frame_info.  */

	  if (inlining_flag)
	    f = find_pc_sect_function (mapped_pc, section);
	  else
	    f = find_pc_sect_function_no_inlined (mapped_pc, section);

	  /* APPLE LOCAL begin address ranges  */
	  if (f != NULL
	      && (msymbol == NULL
		  || (BLOCK_LOWEST_PC (SYMBOL_BLOCK_VALUE (f))
		      >= SYMBOL_VALUE_ADDRESS (msymbol))))
	    {
	      cache_pc_function_low = BLOCK_LOWEST_PC (SYMBOL_BLOCK_VALUE (f));
	      if (BLOCK_RANGES (SYMBOL_BLOCK_VALUE (f)))
		cache_pc_function_high =
		  BLOCK_HIGHEST_PC (SYMBOL_BLOCK_VALUE (f));
	      else
		cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
	  /* APPLE LOCAL end address ranges  */
	      cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
	      cache_pc_function_section = section;
	      goto return_cached_value;
	    }
	}
      else
	{
	  /* Now that static symbols go in the minimal symbol table, perhaps
	     we could just ignore the partial symbols.  But at least for now
	     we use the partial or minimal symbol, whichever is larger.  */
	  psb = find_pc_sect_psymbol (pst, mapped_pc, section);

	  if (psb
	      && (msymbol == NULL ||
		  (SYMBOL_VALUE_ADDRESS (psb)
		   >= SYMBOL_VALUE_ADDRESS (msymbol))))
	    {
	      /* This case isn't being cached currently. */
	      if (address)
		*address = SYMBOL_VALUE_ADDRESS (psb);
	      if (name)
		*name = DEPRECATED_SYMBOL_NAME (psb);
	      /* endaddr non-NULL can't happen here.  */
	      return 1;
	    }
	}
    }

  /* Not in the normal symbol tables, see if the pc is in a known section.
     If it's not, then give up.  This ensures that anything beyond the end
     of the text seg doesn't appear to be part of the last function in the
     text segment.  */

  osect = find_pc_sect_section (mapped_pc, section);

  if (!osect)
    msymbol = NULL;

  /* Must be in the minimal symbol table.  */
  if (msymbol == NULL)
    {
      /* No available symbol.  */
      if (name != NULL)
	*name = 0;
      if (address != NULL)
	*address = 0;
      if (endaddr != NULL)
	*endaddr = 0;
      return 0;
    }

  cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
  cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
  cache_pc_function_section = section;

  /* Use the lesser of the next minimal symbol in the same section, or
     the end of the section, as the end of the function.  */

  /* Step over other symbols at this same address, and symbols in
     other sections, to find the next symbol in this section with
     a different address.  */

  for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
    {
      if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
	  && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
	break;
    }

  if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
      && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
    cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
  else
    /* We got the start address from the last msymbol in the objfile.
       So the end address is the end of the section.  */
    cache_pc_function_high = osect->endaddr;

 return_cached_value:

  if (address)
    {
      if (pc_in_unmapped_range (pc, section))
	*address = overlay_unmapped_address (cache_pc_function_low, section);
      else
	*address = cache_pc_function_low;
    }

  if (name)
    *name = cache_pc_function_name;

  if (endaddr)
    {
      if (pc_in_unmapped_range (pc, section))
	{
	  /* Because the high address is actually beyond the end of
	     the function (and therefore possibly beyond the end of
	     the overlay), we must actually convert (high - 1) and
	     then add one to that. */

	  *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
						   section);
	}
      else
	*endaddr = cache_pc_function_high;
    }

  return 1;
}
Пример #7
0
int
find_pc_partial_function (CORE_ADDR pc, const char **name, CORE_ADDR *address,
			  CORE_ADDR *endaddr, const struct block **block)
{
  struct obj_section *section;
  struct symbol *f;
  struct bound_minimal_symbol msymbol;
  struct compunit_symtab *compunit_symtab = NULL;
  CORE_ADDR mapped_pc;

  /* To ensure that the symbol returned belongs to the correct setion
     (and that the last [random] symbol from the previous section
     isn't returned) try to find the section containing PC.  First try
     the overlay code (which by default returns NULL); and second try
     the normal section code (which almost always succeeds).  */
  section = find_pc_overlay (pc);
  if (section == NULL)
    section = find_pc_section (pc);

  mapped_pc = overlay_mapped_address (pc, section);

  if (mapped_pc >= cache_pc_function_low
      && mapped_pc < cache_pc_function_high
      && section == cache_pc_function_section)
    goto return_cached_value;

  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
  for (objfile *objfile : current_program_space->objfiles ())
    {
      if (objfile->sf)
	{
	  compunit_symtab
	    = objfile->sf->qf->find_pc_sect_compunit_symtab (objfile, msymbol,
							     mapped_pc,
							     section,
							     0);
	}
      if (compunit_symtab != NULL)
	break;
    }

  if (compunit_symtab != NULL)
    {
      /* Checking whether the msymbol has a larger value is for the
	 "pathological" case mentioned in stack.c:find_frame_funname.

	 We use BLOCK_ENTRY_PC instead of BLOCK_START_PC for this
	 comparison because the minimal symbol should refer to the
	 function's entry pc which is not necessarily the lowest
	 address of the function.  This will happen when the function
	 has more than one range and the entry pc is not within the
	 lowest range of addresses.  */
      f = find_pc_sect_function (mapped_pc, section);
      if (f != NULL
	  && (msymbol.minsym == NULL
	      || (BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (f))
		  >= BMSYMBOL_VALUE_ADDRESS (msymbol))))
	{
	  const struct block *b = SYMBOL_BLOCK_VALUE (f);

	  cache_pc_function_name = SYMBOL_LINKAGE_NAME (f);
	  cache_pc_function_section = section;
	  cache_pc_function_block = b;

	  /* For blocks occupying contiguous addresses (i.e. no gaps),
	     the low and high cache addresses are simply the start
	     and end of the block.

	     For blocks with non-contiguous ranges, we have to search
	     for the range containing mapped_pc and then use the start
	     and end of that range.

	     This causes the returned *ADDRESS and *ENDADDR values to
	     be limited to the range in which mapped_pc is found.  See
	     comment preceding declaration of find_pc_partial_function
	     in symtab.h for more information.  */

	  if (BLOCK_CONTIGUOUS_P (b))
	    {
	      cache_pc_function_low = BLOCK_START (b);
	      cache_pc_function_high = BLOCK_END (b);
	    }
	  else
	    {
	      int i;
	      for (i = 0; i < BLOCK_NRANGES (b); i++)
	        {
		  if (BLOCK_RANGE_START (b, i) <= mapped_pc
		      && mapped_pc < BLOCK_RANGE_END (b, i))
		    {
		      cache_pc_function_low = BLOCK_RANGE_START (b, i);
		      cache_pc_function_high = BLOCK_RANGE_END (b, i);
		      break;
		    }
		}
	      /* Above loop should exit via the break.  */
	      gdb_assert (i < BLOCK_NRANGES (b));
	    }


	  goto return_cached_value;
	}
    }

  /* Not in the normal symbol tables, see if the pc is in a known
     section.  If it's not, then give up.  This ensures that anything
     beyond the end of the text seg doesn't appear to be part of the
     last function in the text segment.  */

  if (!section)
    msymbol.minsym = NULL;

  /* Must be in the minimal symbol table.  */
  if (msymbol.minsym == NULL)
    {
      /* No available symbol.  */
      if (name != NULL)
	*name = 0;
      if (address != NULL)
	*address = 0;
      if (endaddr != NULL)
	*endaddr = 0;
      return 0;
    }

  cache_pc_function_low = BMSYMBOL_VALUE_ADDRESS (msymbol);
  cache_pc_function_name = MSYMBOL_LINKAGE_NAME (msymbol.minsym);
  cache_pc_function_section = section;
  cache_pc_function_high = minimal_symbol_upper_bound (msymbol);
  cache_pc_function_block = nullptr;

 return_cached_value:

  if (address)
    {
      if (pc_in_unmapped_range (pc, section))
	*address = overlay_unmapped_address (cache_pc_function_low, section);
      else
	*address = cache_pc_function_low;
    }

  if (name)
    *name = cache_pc_function_name;

  if (endaddr)
    {
      if (pc_in_unmapped_range (pc, section))
	{
	  /* Because the high address is actually beyond the end of
	     the function (and therefore possibly beyond the end of
	     the overlay), we must actually convert (high - 1) and
	     then add one to that.  */

	  *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
						   section);
	}
      else
	*endaddr = cache_pc_function_high;
    }

  if (block != nullptr)
    *block = cache_pc_function_block;

  return 1;
}
Пример #8
0
int
xfer_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len, int write,
	     struct mem_attrib *attrib, struct target_ops *target)
{
  int res;
  struct section_table *p;
  CORE_ADDR nextsectaddr, memend;
  asection *section = NULL;

  if (len <= 0)
    internal_error (__FILE__, __LINE__, _("failed internal consistency check"));

  if (overlay_debugging)
    {
      section = find_pc_overlay (memaddr);
      if (pc_in_unmapped_range (memaddr, section))
	memaddr = overlay_mapped_address (memaddr, section);
    }

  memend = memaddr + len;
  nextsectaddr = memend;

  for (p = target->to_sections; p < target->to_sections_end; p++)
    {
      if (overlay_debugging && section && p->the_bfd_section &&
	  strcmp (section->name, p->the_bfd_section->name) != 0)
	continue;		/* not the section we need */
      if (memaddr >= p->addr)
        {
	  if (memend <= p->endaddr)
	    {
	      /* Entire transfer is within this section.  */
	      if (write)
		res = bfd_set_section_contents (p->bfd, p->the_bfd_section,
						myaddr, memaddr - p->addr,
						len);
	      else
		res = bfd_get_section_contents (p->bfd, p->the_bfd_section,
						myaddr, memaddr - p->addr,
						len);
	      return (res != 0) ? len : 0;
	    }
	  else if (memaddr >= p->endaddr)
	    {
	      /* This section ends before the transfer starts.  */
	      continue;
	    }
	  else
	    {
	      /* This section overlaps the transfer.  Just do half.  */
	      len = p->endaddr - memaddr;
	      if (write)
		res = bfd_set_section_contents (p->bfd, p->the_bfd_section,
						myaddr, memaddr - p->addr,
						len);
	      else
		res = bfd_get_section_contents (p->bfd, p->the_bfd_section,
						myaddr, memaddr - p->addr,
						len);
	      return (res != 0) ? len : 0;
	    }
        }
      else
	nextsectaddr = min (nextsectaddr, p->addr);
    }

  if (nextsectaddr >= memend)
    return 0;			/* We can't help */
  else
    return -(nextsectaddr - memaddr);	/* Next boundary where we can help */
}
Пример #9
0
static int
arm_linux_copy_svc (struct gdbarch *gdbarch, uint32_t insn, CORE_ADDR to,
		    struct regcache *regs, struct displaced_step_closure *dsc)
{
  CORE_ADDR from = dsc->insn_addr;
  struct frame_info *frame;
  unsigned int svc_number = displaced_read_reg (regs, from, 7);

  if (debug_displaced)
    fprintf_unfiltered (gdb_stdlog, "displaced: copying Linux svc insn %.8lx\n",
			(unsigned long) insn);

  frame = get_current_frame ();

  /* Is this a sigreturn or rt_sigreturn syscall?  Note: these are only useful
     for EABI.  */
  if (svc_number == 119 || svc_number == 173)
    {
      if (get_frame_type (frame) == SIGTRAMP_FRAME)
	{
	  CORE_ADDR return_to;
	  struct symtab_and_line sal;

	  if (debug_displaced)
	    fprintf_unfiltered (gdb_stdlog, "displaced: found "
	      "sigreturn/rt_sigreturn SVC call. PC in frame = %lx\n",
	      (unsigned long) get_frame_pc (frame));

	  return_to = frame_unwind_caller_pc (frame);
	  if (debug_displaced)
	    fprintf_unfiltered (gdb_stdlog, "displaced: unwind pc = %lx. "
	      "Setting momentary breakpoint.\n", (unsigned long) return_to);

	  gdb_assert (inferior_thread ()->step_resume_breakpoint == NULL);

	  sal = find_pc_line (return_to, 0);
	  sal.pc = return_to;
	  sal.section = find_pc_overlay (return_to);
	  sal.explicit_pc = 1;

	  frame = get_prev_frame (frame);

	  if (frame)
	    {
	      inferior_thread ()->step_resume_breakpoint
        	= set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame),
					    bp_step_resume);

	      /* We need to make sure we actually insert the momentary
	         breakpoint set above.  */
	      insert_breakpoints ();
	    }
	  else if (debug_displaced)
	    fprintf_unfiltered (gdb_stderr, "displaced: couldn't find previous "
				"frame to set momentary breakpoint for "
				"sigreturn/rt_sigreturn\n");
	}
      else if (debug_displaced)
	fprintf_unfiltered (gdb_stdlog, "displaced: sigreturn/rt_sigreturn "
			    "SVC call not in signal trampoline frame\n");
    }

  /* Preparation: If we detect sigreturn, set momentary breakpoint at resume
		  location, else nothing.
     Insn: unmodified svc.
     Cleanup: if pc lands in scratch space, pc <- insn_addr + 4
              else leave pc alone.  */

  dsc->modinsn[0] = insn;

  dsc->cleanup = &arm_linux_cleanup_svc;
  /* Pretend we wrote to the PC, so cleanup doesn't set PC to the next
     instruction.  */
  dsc->wrote_to_pc = 1;

  return 0;
}