[thirdparty/binutils-gdb.git] / bfd / elf-vxworks.c

/* VxWorks support for ELF
   Copyright 2005, 2007 Free Software Foundation, Inc.

   This file is part of BFD, the Binary File Descriptor library.

   This program 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 of the License, or
   (at your option) any later version.

   This program 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; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston,
   MA 02111-1307, USA.  */

/* This file provides routines used by all VxWorks targets.  */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf-vxworks.h"
#include "elf/vxworks.h"

/* Return true if symbol NAME, as defined by ABFD, is one of the special
   __GOTT_BASE__ or __GOTT_INDEX__ symbols.  */

static bfd_boolean
elf_vxworks_gott_symbol_p (bfd *abfd, const char *name)
{
  char leading;

  leading = bfd_get_symbol_leading_char (abfd);
  if (leading)
    {
      if (*name != leading)
	return FALSE;
      name++;
    }
  return (strcmp (name, "__GOTT_BASE__") == 0
	  || strcmp (name, "__GOTT_INDEX__") == 0);
}

/* Tweak magic VxWorks symbols as they are loaded.  */
bfd_boolean
elf_vxworks_add_symbol_hook (bfd *abfd,
			     struct bfd_link_info *info,
			     Elf_Internal_Sym *sym,
			     const char **namep,
			     flagword *flagsp,
			     asection **secp ATTRIBUTE_UNUSED,
			     bfd_vma *valp ATTRIBUTE_UNUSED)
{
  /* Ideally these "magic" symbols would be exported by libc.so.1
     which would be found via a DT_NEEDED tag, and then handled
     specially by the linker at runtime.  Except shared libraries
     don't even link to libc.so.1 by default...
     If the symbol is imported from, or will be put in a shared library,
     give the symbol weak binding to get the desired samantics.
     This transformation will be undone in
     elf_i386_vxworks_link_output_symbol_hook. */
  if ((info->shared || abfd->flags & DYNAMIC)
      && elf_vxworks_gott_symbol_p (abfd, *namep))
    {
      sym->st_info = ELF_ST_INFO (STB_WEAK, ELF_ST_TYPE (sym->st_info));
      *flagsp |= BSF_WEAK;
    }

  return TRUE;
}

/* Perform VxWorks-specific handling of the create_dynamic_sections hook.
   When creating an executable, set *SRELPLT2_OUT to the .rel(a).plt.unloaded
   section.  */

bfd_boolean
elf_vxworks_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info,
				     asection **srelplt2_out)
{
  struct elf_link_hash_table *htab;
  const struct elf_backend_data *bed;
  asection *s;

  htab = elf_hash_table (info);
  bed = get_elf_backend_data (dynobj);

  if (!info->shared)
    {
      s = bfd_make_section_with_flags (dynobj,
				       bed->default_use_rela_p
				       ? ".rela.plt.unloaded"
				       : ".rel.plt.unloaded",
				       SEC_HAS_CONTENTS | SEC_IN_MEMORY
				       | SEC_READONLY | SEC_LINKER_CREATED);
      if (s == NULL
	  || !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
	return FALSE;

      *srelplt2_out = s;
    }

  /* Mark the GOT and PLT symbols as having relocations; they might
     not, but we won't know for sure until we build the GOT in
     finish_dynamic_symbol.  Also make sure that the GOT symbol
     is entered into the dynamic symbol table; the loader uses it
     to initialize __GOTT_BASE__[__GOTT_INDEX__].  */
  if (htab->hgot)
    {
      htab->hgot->indx = -2;
      htab->hgot->other &= ~ELF_ST_VISIBILITY (-1);
      htab->hgot->forced_local = 0;
      if (!bfd_elf_link_record_dynamic_symbol (info, htab->hgot))
	return FALSE;
    }
  if (htab->hplt)
    {
      htab->hplt->indx = -2;
      htab->hplt->type = STT_FUNC;
    }

  return TRUE;
}

/* Tweak magic VxWorks symbols as they are written to the output file.  */
bfd_boolean
elf_vxworks_link_output_symbol_hook (struct bfd_link_info *info
				       ATTRIBUTE_UNUSED,
				     const char *name,
				     Elf_Internal_Sym *sym,
				     asection *input_sec ATTRIBUTE_UNUSED,
				     struct elf_link_hash_entry *h)
{
  /* Reverse the effects of the hack in elf_vxworks_add_symbol_hook.  */
  if (h
      && h->root.type == bfd_link_hash_undefweak
      && elf_vxworks_gott_symbol_p (h->root.u.undef.abfd, name))
    sym->st_info = ELF_ST_INFO (STB_GLOBAL, ELF_ST_TYPE (sym->st_info));

  return TRUE;
}


/* Copy relocations into the output file.  Fixes up relocations againt PLT
   entries, then calls the generic routine.  */

bfd_boolean
elf_vxworks_emit_relocs (bfd *output_bfd,
			 asection *input_section,
			 Elf_Internal_Shdr *input_rel_hdr,
			 Elf_Internal_Rela *internal_relocs,
			 struct elf_link_hash_entry **rel_hash)
{
  const struct elf_backend_data *bed;
  Elf_Internal_Rela *irela;
  Elf_Internal_Rela *irelaend;
  int j;

  bed = get_elf_backend_data (output_bfd);

  irela = internal_relocs;
  irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
		      * bed->s->int_rels_per_ext_rel);
  while (irela < irelaend)
    {
      if ((output_bfd->flags & (DYNAMIC|EXEC_P))
	  && *rel_hash
	  && (*rel_hash)->def_dynamic
	  && !(*rel_hash)->def_regular
	  && ((*rel_hash)->root.type == bfd_link_hash_defined
	      || (*rel_hash)->root.type == bfd_link_hash_defweak)
	  && (*rel_hash)->root.u.def.section->output_section != NULL)
	{
	  /* This is a relocation from an executable or shared library
	     against a symbol in a different shared library.  We are
	     creating a definition in the output file but it does not come
	     from any of our normal (.o) files. ie. a PLT stub.
	     Normally this would be a relocation against against SHN_UNDEF
	     with the VMA of the PLT stub.  This upsets the VxWorks loader.
	     Convert it to a section-relative relocation.
	     This gets some other symbols (for instance .dynbss),
	     but is conservatively correct.  */
	  for (j = 0; j < bed->s->int_rels_per_ext_rel; j++)
	    {
	      asection *sec = (*rel_hash)->root.u.def.section;
	      int this_idx = sec->output_section->target_index;

	      irela[j].r_info = ELF32_R_INFO (this_idx,
		  ELF32_R_TYPE (irela[j].r_info));
	      irela[j].r_addend += (*rel_hash)->root.u.def.value;
	      irela[j].r_addend += sec->output_offset;
	    }
	  /* Stop the generic routine adjusting this entry.  */
	  *rel_hash = NULL;
	}
      irela += bed->s->int_rels_per_ext_rel;
      rel_hash++;
    }
  return _bfd_elf_link_output_relocs (output_bfd, input_section,
				      input_rel_hdr, internal_relocs,
				      rel_hash);
}


/* Set the sh_link and sh_info fields on the static plt relocation secton.  */

void
elf_vxworks_final_write_processing (bfd *abfd,
				    bfd_boolean linker ATTRIBUTE_UNUSED)
{
  asection * sec;
  struct bfd_elf_section_data *d;

  sec = bfd_get_section_by_name (abfd, ".rel.plt.unloaded");
  if (!sec)
    sec = bfd_get_section_by_name (abfd, ".rela.plt.unloaded");
  if (!sec)
    return;
  d = elf_section_data (sec);
  d->this_hdr.sh_link = elf_tdata (abfd)->symtab_section;
  sec = bfd_get_section_by_name (abfd, ".plt");
  if (sec)
    d->this_hdr.sh_info = elf_section_data (sec)->this_idx;
}

/* Add the dynamic entries required by VxWorks.  These point to the
   tls sections.  */

bfd_boolean
elf_vxworks_add_dynamic_entries (bfd *output_bfd, struct bfd_link_info *info)
{
  if (bfd_get_section_by_name (output_bfd, ".tls_data"))
    {
      if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_START, 0)
	  || !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_SIZE, 0)
	  || !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_ALIGN, 0))
	return FALSE;
    }
  if (bfd_get_section_by_name (output_bfd, ".tls_vars"))
    {
      if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_START, 0)
	  || !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_SIZE, 0))
	return FALSE;
    }
  return TRUE;
}

/* If *DYN is one of the VxWorks-specific dynamic entries, then fill
   in the value now  and return TRUE.  Otherwise return FALSE.  */

bfd_boolean
elf_vxworks_finish_dynamic_entry (bfd *output_bfd, Elf_Internal_Dyn *dyn)
{
  asection *sec;
  
  switch (dyn->d_tag)
    {
    default:
      return FALSE;
      
    case DT_VX_WRS_TLS_DATA_START:
      sec = bfd_get_section_by_name (output_bfd, ".tls_data");
      dyn->d_un.d_ptr = sec->vma;
      break;
      
    case DT_VX_WRS_TLS_DATA_SIZE:
      sec = bfd_get_section_by_name (output_bfd, ".tls_data");
      dyn->d_un.d_val = sec->size;
      break;
      
    case DT_VX_WRS_TLS_DATA_ALIGN:
      sec = bfd_get_section_by_name (output_bfd, ".tls_data");
      dyn->d_un.d_val
	= (bfd_size_type)1 << bfd_get_section_alignment (abfd, sec);
      break;
      
    case DT_VX_WRS_TLS_VARS_START:
      sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
      dyn->d_un.d_ptr = sec->vma;
      break;
      
    case DT_VX_WRS_TLS_VARS_SIZE:
      sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
      dyn->d_un.d_val = sec->size;
      break;
    }
  return TRUE;
}
Commit	Line	Data
eac338cf	1	/* VxWorks support for ELF
3db64b00	2	Copyright 2005, 2007 Free Software Foundation, Inc.
eac338cf PB	3
	4	This file is part of BFD, the Binary File Descriptor library.
	5
	6	This program is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
cd123cb7	8	the Free Software Foundation; either version 3 of the License, or
eac338cf PB	9	(at your option) any later version.
	10
	11	This program is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with this program; if not, write to the Free Software
cd123cb7 NC	18	Foundation, Inc., 59 Temple Place - Suite 330, Boston,
cd123cb7 NC	19	MA 02111-1307, USA. */
eac338cf PB	20
	21	/* This file provides routines used by all VxWorks targets. */
	22
eac338cf	23	#include "sysdep.h"
3db64b00	24	#include "bfd.h"
eac338cf PB	25	#include "libbfd.h"
	26	#include "elf-bfd.h"
	27	#include "elf-vxworks.h"
4d2c0abd	28	#include "elf/vxworks.h"
eac338cf	29
55e6e397 RS	30	/* Return true if symbol NAME, as defined by ABFD, is one of the special
	31	__GOTT_BASE__ or __GOTT_INDEX__ symbols. */
	32
	33	static bfd_boolean
	34	elf_vxworks_gott_symbol_p (bfd abfd, const char name)
	35	{
	36	char leading;
	37
	38	leading = bfd_get_symbol_leading_char (abfd);
	39	if (leading)
	40	{
	41	if (*name != leading)
	42	return FALSE;
	43	name++;
	44	}
	45	return (strcmp (name, "__GOTT_BASE__") == 0
	46	\|\| strcmp (name, "__GOTT_INDEX__") == 0);
	47	}
	48
eac338cf PB	49	/* Tweak magic VxWorks symbols as they are loaded. */
eac338cf PB	50	bfd_boolean
55e6e397	51	elf_vxworks_add_symbol_hook (bfd *abfd,
eac338cf PB	52	struct bfd_link_info *info,
	53	Elf_Internal_Sym *sym,
	54	const char **namep,
	55	flagword *flagsp,
	56	asection **secp ATTRIBUTE_UNUSED,
	57	bfd_vma *valp ATTRIBUTE_UNUSED)
	58	{
	59	/* Ideally these "magic" symbols would be exported by libc.so.1
	60	which would be found via a DT_NEEDED tag, and then handled
	61	specially by the linker at runtime. Except shared libraries
	62	don't even link to libc.so.1 by default...
	63	If the symbol is imported from, or will be put in a shared library,
	64	give the symbol weak binding to get the desired samantics.
	65	This transformation will be undone in
	66	elf_i386_vxworks_link_output_symbol_hook. */
	67	if ((info->shared \|\| abfd->flags & DYNAMIC)
55e6e397	68	&& elf_vxworks_gott_symbol_p (abfd, *namep))
eac338cf PB	69	{
	70	sym->st_info = ELF_ST_INFO (STB_WEAK, ELF_ST_TYPE (sym->st_info));
	71	*flagsp \|= BSF_WEAK;
	72	}
	73
	74	return TRUE;
	75	}
	76
711de32c RS	77	/* Perform VxWorks-specific handling of the create_dynamic_sections hook.
	78	When creating an executable, set *SRELPLT2_OUT to the .rel(a).plt.unloaded
	79	section. */
	80
	81	bfd_boolean
	82	elf_vxworks_create_dynamic_sections (bfd dynobj, struct bfd_link_info info,
	83	asection **srelplt2_out)
	84	{
	85	struct elf_link_hash_table *htab;
	86	const struct elf_backend_data *bed;
	87	asection *s;
	88
	89	htab = elf_hash_table (info);
	90	bed = get_elf_backend_data (dynobj);
	91
	92	if (!info->shared)
	93	{
	94	s = bfd_make_section_with_flags (dynobj,
	95	bed->default_use_rela_p
	96	? ".rela.plt.unloaded"
	97	: ".rel.plt.unloaded",
	98	SEC_HAS_CONTENTS \| SEC_IN_MEMORY
	99	\| SEC_READONLY \| SEC_LINKER_CREATED);
	100	if (s == NULL
	101	\|\| !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
	102	return FALSE;
	103
	104	*srelplt2_out = s;
	105	}
	106
	107	/* Mark the GOT and PLT symbols as having relocations; they might
	108	not, but we won't know for sure until we build the GOT in
	109	finish_dynamic_symbol. Also make sure that the GOT symbol
	110	is entered into the dynamic symbol table; the loader uses it
	111	to initialize __GOTT_BASE__[__GOTT_INDEX__]. */
	112	if (htab->hgot)
	113	{
	114	htab->hgot->indx = -2;
	115	htab->hgot->other &= ~ELF_ST_VISIBILITY (-1);
	116	htab->hgot->forced_local = 0;
	117	if (!bfd_elf_link_record_dynamic_symbol (info, htab->hgot))
	118	return FALSE;
	119	}
	120	if (htab->hplt)
	121	{
	122	htab->hplt->indx = -2;
	123	htab->hplt->type = STT_FUNC;
	124	}
	125
	126	return TRUE;
	127	}
eac338cf PB	128
	129	/* Tweak magic VxWorks symbols as they are written to the output file. */
	130	bfd_boolean
9c72ff84 RS	131	elf_vxworks_link_output_symbol_hook (struct bfd_link_info *info
	132	ATTRIBUTE_UNUSED,
	133	const char *name,
	134	Elf_Internal_Sym *sym,
	135	asection *input_sec ATTRIBUTE_UNUSED,
55e6e397	136	struct elf_link_hash_entry *h)
eac338cf PB	137	{
eac338cf PB	138	/* Reverse the effects of the hack in elf_vxworks_add_symbol_hook. */
55e6e397 RS	139	if (h
	140	&& h->root.type == bfd_link_hash_undefweak
	141	&& elf_vxworks_gott_symbol_p (h->root.u.undef.abfd, name))
eac338cf PB	142	sym->st_info = ELF_ST_INFO (STB_GLOBAL, ELF_ST_TYPE (sym->st_info));
	143
	144	return TRUE;
	145	}
	146
	147
	148	/* Copy relocations into the output file. Fixes up relocations againt PLT
	149	entries, then calls the generic routine. */
	150
	151	bfd_boolean
	152	elf_vxworks_emit_relocs (bfd *output_bfd,
	153	asection *input_section,
	154	Elf_Internal_Shdr *input_rel_hdr,
	155	Elf_Internal_Rela *internal_relocs,
	156	struct elf_link_hash_entry **rel_hash)
	157	{
	158	const struct elf_backend_data *bed;
	159	Elf_Internal_Rela *irela;
	160	Elf_Internal_Rela *irelaend;
	161	int j;
	162
	163	bed = get_elf_backend_data (output_bfd);
	164
	165	irela = internal_relocs;
	166	irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
	167	* bed->s->int_rels_per_ext_rel);
	168	while (irela < irelaend)
	169	{
	170	if ((output_bfd->flags & (DYNAMIC\|EXEC_P))
	171	&& *rel_hash
	172	&& (*rel_hash)->def_dynamic
	173	&& !(*rel_hash)->def_regular
8776bb8a	174	&& ((*rel_hash)->root.type == bfd_link_hash_defined
c10564a9	175	\|\| (*rel_hash)->root.type == bfd_link_hash_defweak)
eac338cf PB	176	&& (*rel_hash)->root.u.def.section->output_section != NULL)
	177	{
	178	/* This is a relocation from an executable or shared library
	179	against a symbol in a different shared library. We are
	180	creating a definition in the output file but it does not come
	181	from any of our normal (.o) files. ie. a PLT stub.
	182	Normally this would be a relocation against against SHN_UNDEF
	183	with the VMA of the PLT stub. This upsets the VxWorks loader.
	184	Convert it to a section-relative relocation.
	185	This gets some other symbols (for instance .dynbss),
	186	but is conservatively correct. */
	187	for (j = 0; j < bed->s->int_rels_per_ext_rel; j++)
	188	{
	189	asection sec = (rel_hash)->root.u.def.section;
55e6e397	190	int this_idx = sec->output_section->target_index;
eac338cf PB	191
	192	irela[j].r_info = ELF32_R_INFO (this_idx,
	193	ELF32_R_TYPE (irela[j].r_info));
	194	irela[j].r_addend += (*rel_hash)->root.u.def.value;
	195	irela[j].r_addend += sec->output_offset;
	196	}
	197	/* Stop the generic routine adjusting this entry. */
	198	*rel_hash = NULL;
	199	}
	200	irela += bed->s->int_rels_per_ext_rel;
	201	rel_hash++;
	202	}
	203	return _bfd_elf_link_output_relocs (output_bfd, input_section,
	204	input_rel_hdr, internal_relocs,
	205	rel_hash);
	206	}
	207
	208
	209	/* Set the sh_link and sh_info fields on the static plt relocation secton. */
	210
	211	void
	212	elf_vxworks_final_write_processing (bfd *abfd,
	213	bfd_boolean linker ATTRIBUTE_UNUSED)
	214	{
	215	asection * sec;
	216	struct bfd_elf_section_data *d;
	217
	218	sec = bfd_get_section_by_name (abfd, ".rel.plt.unloaded");
9d8504b1 PB	219	if (!sec)
9d8504b1 PB	220	sec = bfd_get_section_by_name (abfd, ".rela.plt.unloaded");
eac338cf PB	221	if (!sec)
	222	return;
	223	d = elf_section_data (sec);
	224	d->this_hdr.sh_link = elf_tdata (abfd)->symtab_section;
	225	sec = bfd_get_section_by_name (abfd, ".plt");
	226	if (sec)
	227	d->this_hdr.sh_info = elf_section_data (sec)->this_idx;
	228	}
4d2c0abd NS	229
	230	/* Add the dynamic entries required by VxWorks. These point to the
	231	tls sections. */
	232
	233	bfd_boolean
	234	elf_vxworks_add_dynamic_entries (bfd output_bfd, struct bfd_link_info info)
	235	{
	236	if (bfd_get_section_by_name (output_bfd, ".tls_data"))
	237	{
	238	if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_START, 0)
	239	\|\| !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_SIZE, 0)
	240	\|\| !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_ALIGN, 0))
	241	return FALSE;
	242	}
	243	if (bfd_get_section_by_name (output_bfd, ".tls_vars"))
	244	{
	245	if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_START, 0)
	246	\|\| !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_SIZE, 0))
	247	return FALSE;
	248	}
	249	return TRUE;
	250	}
	251
	252	/* If *DYN is one of the VxWorks-specific dynamic entries, then fill
	253	in the value now and return TRUE. Otherwise return FALSE. */
	254
	255	bfd_boolean
	256	elf_vxworks_finish_dynamic_entry (bfd output_bfd, Elf_Internal_Dyn dyn)
	257	{
	258	asection *sec;
	259
	260	switch (dyn->d_tag)
	261	{
	262	default:
	263	return FALSE;
	264
	265	case DT_VX_WRS_TLS_DATA_START:
	266	sec = bfd_get_section_by_name (output_bfd, ".tls_data");
	267	dyn->d_un.d_ptr = sec->vma;
	268	break;
	269
	270	case DT_VX_WRS_TLS_DATA_SIZE:
	271	sec = bfd_get_section_by_name (output_bfd, ".tls_data");
	272	dyn->d_un.d_val = sec->size;
	273	break;
	274
	275	case DT_VX_WRS_TLS_DATA_ALIGN:
	276	sec = bfd_get_section_by_name (output_bfd, ".tls_data");
	277	dyn->d_un.d_val
	278	= (bfd_size_type)1 << bfd_get_section_alignment (abfd, sec);
	279	break;
	280
	281	case DT_VX_WRS_TLS_VARS_START:
	282	sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
	283	dyn->d_un.d_ptr = sec->vma;
	284	break;
	285
	286	case DT_VX_WRS_TLS_VARS_SIZE:
	287	sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
	288	dyn->d_un.d_val = sec->size;
	289	break;
	290	}
	291	return TRUE;
	292	}
293
294