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

/* VxWorks support for ELF
   Copyright (C) 2005-2019 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, see <http://www.gnu.org/licenses/>.  */

/* 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 ((bfd_link_pic (info) || 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 (!bfd_link_pic (info))
    {
      s = bfd_make_section_anyway_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 (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.  */
int
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 1;
}

/* Copy relocations into the output file.  Fixes up relocations against 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;
  int j;

  bed = get_elf_backend_data (output_bfd);

  if (output_bfd->flags & (DYNAMIC|EXEC_P))
    {
      Elf_Internal_Rela *irela;
      Elf_Internal_Rela *irelaend;
      struct elf_link_hash_entry **hash_ptr;

      for (irela = internal_relocs,
	     irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
				 * bed->s->int_rels_per_ext_rel),
	     hash_ptr = rel_hash;
	   irela < irelaend;
	   irela += bed->s->int_rels_per_ext_rel,
	     hash_ptr++)
	{
	  if (*hash_ptr
	      && (*hash_ptr)->def_dynamic
	      && !(*hash_ptr)->def_regular
	      && ((*hash_ptr)->root.type == bfd_link_hash_defined
		  || (*hash_ptr)->root.type == bfd_link_hash_defweak)
	      && (*hash_ptr)->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 = (*hash_ptr)->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 += (*hash_ptr)->root.u.def.value;
		  irela[j].r_addend += sec->output_offset;
		}
	      /* Stop the generic routine adjusting this entry.  */
	      *hash_ptr = NULL;
	    }
	}
    }
  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.  */

bfd_boolean
elf_vxworks_final_write_processing (bfd *abfd)
{
  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)
    {
      d = elf_section_data (sec);
      d->this_hdr.sh_link = elf_onesymtab (abfd);
      sec = bfd_get_section_by_name (abfd, ".plt");
      if (sec)
	d->this_hdr.sh_info = elf_section_data (sec)->this_idx;
    }
  return _bfd_elf_final_write_processing (abfd);
}

/* 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_section_alignment (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
82704155	2	Copyright (C) 2005-2019 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
08832196	17	along with this program. If not, see <http://www.gnu.org/licenses/>. */
eac338cf PB	18
	19	/* This file provides routines used by all VxWorks targets. */
	20
eac338cf	21	#include "sysdep.h"
3db64b00	22	#include "bfd.h"
eac338cf PB	23	#include "libbfd.h"
	24	#include "elf-bfd.h"
	25	#include "elf-vxworks.h"
4d2c0abd	26	#include "elf/vxworks.h"
eac338cf	27
55e6e397 RS	28	/* Return true if symbol NAME, as defined by ABFD, is one of the special
	29	__GOTT_BASE__ or __GOTT_INDEX__ symbols. */
	30
	31	static bfd_boolean
	32	elf_vxworks_gott_symbol_p (bfd abfd, const char name)
	33	{
	34	char leading;
	35
	36	leading = bfd_get_symbol_leading_char (abfd);
	37	if (leading)
	38	{
	39	if (*name != leading)
	40	return FALSE;
	41	name++;
	42	}
	43	return (strcmp (name, "__GOTT_BASE__") == 0
	44	\|\| strcmp (name, "__GOTT_INDEX__") == 0);
	45	}
	46
eac338cf PB	47	/* Tweak magic VxWorks symbols as they are loaded. */
eac338cf PB	48	bfd_boolean
55e6e397	49	elf_vxworks_add_symbol_hook (bfd *abfd,
eac338cf PB	50	struct bfd_link_info *info,
	51	Elf_Internal_Sym *sym,
	52	const char **namep,
	53	flagword *flagsp,
	54	asection **secp ATTRIBUTE_UNUSED,
	55	bfd_vma *valp ATTRIBUTE_UNUSED)
	56	{
	57	/* Ideally these "magic" symbols would be exported by libc.so.1
	58	which would be found via a DT_NEEDED tag, and then handled
	59	specially by the linker at runtime. Except shared libraries
	60	don't even link to libc.so.1 by default...
	61	If the symbol is imported from, or will be put in a shared library,
	62	give the symbol weak binding to get the desired samantics.
	63	This transformation will be undone in
	64	elf_i386_vxworks_link_output_symbol_hook. */
0e1862bb	65	if ((bfd_link_pic (info) \|\| abfd->flags & DYNAMIC)
55e6e397	66	&& elf_vxworks_gott_symbol_p (abfd, *namep))
eac338cf PB	67	{
	68	sym->st_info = ELF_ST_INFO (STB_WEAK, ELF_ST_TYPE (sym->st_info));
	69	*flagsp \|= BSF_WEAK;
	70	}
	71
	72	return TRUE;
	73	}
	74
711de32c RS	75	/* Perform VxWorks-specific handling of the create_dynamic_sections hook.
	76	When creating an executable, set *SRELPLT2_OUT to the .rel(a).plt.unloaded
	77	section. */
	78
	79	bfd_boolean
	80	elf_vxworks_create_dynamic_sections (bfd dynobj, struct bfd_link_info info,
	81	asection **srelplt2_out)
	82	{
	83	struct elf_link_hash_table *htab;
	84	const struct elf_backend_data *bed;
	85	asection *s;
	86
	87	htab = elf_hash_table (info);
	88	bed = get_elf_backend_data (dynobj);
	89
0e1862bb	90	if (!bfd_link_pic (info))
711de32c	91	{
3d4d4302 AM	92	s = bfd_make_section_anyway_with_flags (dynobj,
	93	bed->default_use_rela_p
	94	? ".rela.plt.unloaded"
	95	: ".rel.plt.unloaded",
	96	SEC_HAS_CONTENTS \| SEC_IN_MEMORY
	97	\| SEC_READONLY
	98	\| SEC_LINKER_CREATED);
711de32c	99	if (s == NULL
fd361982	100	\|\| !bfd_set_section_alignment (s, bed->s->log_file_align))
711de32c RS	101	return FALSE;
	102
	103	*srelplt2_out = s;
	104	}
	105
	106	/* Mark the GOT and PLT symbols as having relocations; they might
	107	not, but we won't know for sure until we build the GOT in
	108	finish_dynamic_symbol. Also make sure that the GOT symbol
	109	is entered into the dynamic symbol table; the loader uses it
	110	to initialize __GOTT_BASE__[__GOTT_INDEX__]. */
	111	if (htab->hgot)
	112	{
	113	htab->hgot->indx = -2;
	114	htab->hgot->other &= ~ELF_ST_VISIBILITY (-1);
	115	htab->hgot->forced_local = 0;
	116	if (!bfd_elf_link_record_dynamic_symbol (info, htab->hgot))
	117	return FALSE;
	118	}
	119	if (htab->hplt)
	120	{
	121	htab->hplt->indx = -2;
	122	htab->hplt->type = STT_FUNC;
	123	}
	124
	125	return TRUE;
	126	}
eac338cf PB	127
eac338cf PB	128	/* Tweak magic VxWorks symbols as they are written to the output file. */
6e0b88f1	129	int
9c72ff84 RS	130	elf_vxworks_link_output_symbol_hook (struct bfd_link_info *info
	131	ATTRIBUTE_UNUSED,
	132	const char *name,
	133	Elf_Internal_Sym *sym,
	134	asection *input_sec ATTRIBUTE_UNUSED,
55e6e397	135	struct elf_link_hash_entry *h)
eac338cf PB	136	{
eac338cf PB	137	/* Reverse the effects of the hack in elf_vxworks_add_symbol_hook. */
55e6e397 RS	138	if (h
	139	&& h->root.type == bfd_link_hash_undefweak
	140	&& elf_vxworks_gott_symbol_p (h->root.u.undef.abfd, name))
eac338cf PB	141	sym->st_info = ELF_ST_INFO (STB_GLOBAL, ELF_ST_TYPE (sym->st_info));
eac338cf PB	142
6e0b88f1	143	return 1;
eac338cf PB	144	}
eac338cf PB	145
6b60be10	146	/* Copy relocations into the output file. Fixes up relocations against PLT
eac338cf PB	147	entries, then calls the generic routine. */
	148
	149	bfd_boolean
	150	elf_vxworks_emit_relocs (bfd *output_bfd,
	151	asection *input_section,
	152	Elf_Internal_Shdr *input_rel_hdr,
	153	Elf_Internal_Rela *internal_relocs,
	154	struct elf_link_hash_entry **rel_hash)
	155	{
	156	const struct elf_backend_data *bed;
eac338cf PB	157	int j;
	158
	159	bed = get_elf_backend_data (output_bfd);
	160
6b60be10	161	if (output_bfd->flags & (DYNAMIC\|EXEC_P))
eac338cf	162	{
6b60be10 NS	163	Elf_Internal_Rela *irela;
	164	Elf_Internal_Rela *irelaend;
	165	struct elf_link_hash_entry **hash_ptr;
	166
	167	for (irela = internal_relocs,
	168	irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
	169	* bed->s->int_rels_per_ext_rel),
	170	hash_ptr = rel_hash;
	171	irela < irelaend;
	172	irela += bed->s->int_rels_per_ext_rel,
	173	hash_ptr++)
eac338cf	174	{
6b60be10 NS	175	if (*hash_ptr
	176	&& (*hash_ptr)->def_dynamic
	177	&& !(*hash_ptr)->def_regular
	178	&& ((*hash_ptr)->root.type == bfd_link_hash_defined
	179	\|\| (*hash_ptr)->root.type == bfd_link_hash_defweak)
	180	&& (*hash_ptr)->root.u.def.section->output_section != NULL)
eac338cf	181	{
6b60be10	182	/* This is a relocation from an executable or shared
07d6d2b8 AM	183	library against a symbol in a different shared
	184	library. We are creating a definition in the output
	185	file but it does not come from any of our normal (.o)
	186	files. ie. a PLT stub. Normally this would be a
	187	relocation against against SHN_UNDEF with the VMA of
	188	the PLT stub. This upsets the VxWorks loader.
	189	Convert it to a section-relative relocation. This
	190	gets some other symbols (for instance .dynbss), but
	191	is conservatively correct. */
6b60be10 NS	192	for (j = 0; j < bed->s->int_rels_per_ext_rel; j++)
	193	{
	194	asection sec = (hash_ptr)->root.u.def.section;
	195	int this_idx = sec->output_section->target_index;
68ffbac6	196
6b60be10 NS	197	irela[j].r_info
	198	= ELF32_R_INFO (this_idx, ELF32_R_TYPE (irela[j].r_info));
	199	irela[j].r_addend += (*hash_ptr)->root.u.def.value;
	200	irela[j].r_addend += sec->output_offset;
	201	}
	202	/* Stop the generic routine adjusting this entry. */
	203	*hash_ptr = NULL;
eac338cf	204	}
eac338cf	205	}
eac338cf PB	206	}
	207	return _bfd_elf_link_output_relocs (output_bfd, input_section,
	208	input_rel_hdr, internal_relocs,
	209	rel_hash);
	210	}
	211
	212
	213	/* Set the sh_link and sh_info fields on the static plt relocation secton. */
	214
cc364be6 AM	215	bfd_boolean
cc364be6 AM	216	elf_vxworks_final_write_processing (bfd *abfd)
eac338cf PB	217	{
	218	asection * sec;
	219	struct bfd_elf_section_data *d;
	220
	221	sec = bfd_get_section_by_name (abfd, ".rel.plt.unloaded");
9d8504b1 PB	222	if (!sec)
9d8504b1 PB	223	sec = bfd_get_section_by_name (abfd, ".rela.plt.unloaded");
eac338cf	224	if (sec)
c5e20471 AM	225	{
	226	d = elf_section_data (sec);
	227	d->this_hdr.sh_link = elf_onesymtab (abfd);
	228	sec = bfd_get_section_by_name (abfd, ".plt");
	229	if (sec)
	230	d->this_hdr.sh_info = elf_section_data (sec)->this_idx;
	231	}
cc364be6	232	return _bfd_elf_final_write_processing (abfd);
eac338cf	233	}
4d2c0abd NS	234
	235	/* Add the dynamic entries required by VxWorks. These point to the
	236	tls sections. */
	237
	238	bfd_boolean
	239	elf_vxworks_add_dynamic_entries (bfd output_bfd, struct bfd_link_info info)
	240	{
	241	if (bfd_get_section_by_name (output_bfd, ".tls_data"))
	242	{
	243	if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_START, 0)
	244	\|\| !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_SIZE, 0)
	245	\|\| !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_DATA_ALIGN, 0))
	246	return FALSE;
	247	}
	248	if (bfd_get_section_by_name (output_bfd, ".tls_vars"))
	249	{
	250	if (!_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_START, 0)
	251	\|\| !_bfd_elf_add_dynamic_entry (info, DT_VX_WRS_TLS_VARS_SIZE, 0))
	252	return FALSE;
	253	}
	254	return TRUE;
	255	}
	256
	257	/* If *DYN is one of the VxWorks-specific dynamic entries, then fill
	258	in the value now and return TRUE. Otherwise return FALSE. */
	259
	260	bfd_boolean
	261	elf_vxworks_finish_dynamic_entry (bfd output_bfd, Elf_Internal_Dyn dyn)
	262	{
	263	asection *sec;
68ffbac6	264
4d2c0abd NS	265	switch (dyn->d_tag)
	266	{
	267	default:
	268	return FALSE;
68ffbac6	269
4d2c0abd NS	270	case DT_VX_WRS_TLS_DATA_START:
	271	sec = bfd_get_section_by_name (output_bfd, ".tls_data");
	272	dyn->d_un.d_ptr = sec->vma;
	273	break;
68ffbac6	274
4d2c0abd NS	275	case DT_VX_WRS_TLS_DATA_SIZE:
	276	sec = bfd_get_section_by_name (output_bfd, ".tls_data");
	277	dyn->d_un.d_val = sec->size;
	278	break;
68ffbac6	279
4d2c0abd NS	280	case DT_VX_WRS_TLS_DATA_ALIGN:
4d2c0abd NS	281	sec = bfd_get_section_by_name (output_bfd, ".tls_data");
fd361982	282	dyn->d_un.d_val = (bfd_size_type) 1 << bfd_section_alignment (sec);
4d2c0abd	283	break;
68ffbac6	284
4d2c0abd NS	285	case DT_VX_WRS_TLS_VARS_START:
	286	sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
	287	dyn->d_un.d_ptr = sec->vma;
	288	break;
68ffbac6	289
4d2c0abd NS	290	case DT_VX_WRS_TLS_VARS_SIZE:
	291	sec = bfd_get_section_by_name (output_bfd, ".tls_vars");
	292	dyn->d_un.d_val = sec->size;
	293	break;
	294	}
	295	return TRUE;
	296	}
	297
	298