1 /* VxWorks support for ELF
2 Copyright 2005, 2007 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
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
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
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.
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
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston,
19 MA 02111-1307, USA. */
21 /* This file provides routines used by all VxWorks targets. */
27 #include "elf-vxworks.h"
28 #include "elf/vxworks.h"
30 /* Return true if symbol NAME, as defined by ABFD, is one of the special
31 __GOTT_BASE__ or __GOTT_INDEX__ symbols. */
34 elf_vxworks_gott_symbol_p (bfd
*abfd
, const char *name
)
38 leading
= bfd_get_symbol_leading_char (abfd
);
45 return (strcmp (name
, "__GOTT_BASE__") == 0
46 || strcmp (name
, "__GOTT_INDEX__") == 0);
49 /* Tweak magic VxWorks symbols as they are loaded. */
51 elf_vxworks_add_symbol_hook (bfd
*abfd
,
52 struct bfd_link_info
*info
,
53 Elf_Internal_Sym
*sym
,
56 asection
**secp ATTRIBUTE_UNUSED
,
57 bfd_vma
*valp ATTRIBUTE_UNUSED
)
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
)
68 && elf_vxworks_gott_symbol_p (abfd
, *namep
))
70 sym
->st_info
= ELF_ST_INFO (STB_WEAK
, ELF_ST_TYPE (sym
->st_info
));
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
82 elf_vxworks_create_dynamic_sections (bfd
*dynobj
, struct bfd_link_info
*info
,
83 asection
**srelplt2_out
)
85 struct elf_link_hash_table
*htab
;
86 const struct elf_backend_data
*bed
;
89 htab
= elf_hash_table (info
);
90 bed
= get_elf_backend_data (dynobj
);
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
);
101 || !bfd_set_section_alignment (dynobj
, s
, bed
->s
->log_file_align
))
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__]. */
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
))
122 htab
->hplt
->indx
= -2;
123 htab
->hplt
->type
= STT_FUNC
;
129 /* Tweak magic VxWorks symbols as they are written to the output file. */
131 elf_vxworks_link_output_symbol_hook (struct bfd_link_info
*info
134 Elf_Internal_Sym
*sym
,
135 asection
*input_sec ATTRIBUTE_UNUSED
,
136 struct elf_link_hash_entry
*h
)
138 /* Reverse the effects of the hack in elf_vxworks_add_symbol_hook. */
140 && h
->root
.type
== bfd_link_hash_undefweak
141 && elf_vxworks_gott_symbol_p (h
->root
.u
.undef
.abfd
, name
))
142 sym
->st_info
= ELF_ST_INFO (STB_GLOBAL
, ELF_ST_TYPE (sym
->st_info
));
148 /* Copy relocations into the output file. Fixes up relocations againt PLT
149 entries, then calls the generic routine. */
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
)
158 const struct elf_backend_data
*bed
;
159 Elf_Internal_Rela
*irela
;
160 Elf_Internal_Rela
*irelaend
;
163 bed
= get_elf_backend_data (output_bfd
);
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
)
170 if ((output_bfd
->flags
& (DYNAMIC
|EXEC_P
))
172 && (*rel_hash
)->def_dynamic
173 && !(*rel_hash
)->def_regular
174 && ((*rel_hash
)->root
.type
== bfd_link_hash_defined
175 || (*rel_hash
)->root
.type
== bfd_link_hash_defweak
)
176 && (*rel_hash
)->root
.u
.def
.section
->output_section
!= NULL
)
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
++)
189 asection
*sec
= (*rel_hash
)->root
.u
.def
.section
;
190 int this_idx
= sec
->output_section
->target_index
;
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
;
197 /* Stop the generic routine adjusting this entry. */
200 irela
+= bed
->s
->int_rels_per_ext_rel
;
203 return _bfd_elf_link_output_relocs (output_bfd
, input_section
,
204 input_rel_hdr
, internal_relocs
,
209 /* Set the sh_link and sh_info fields on the static plt relocation secton. */
212 elf_vxworks_final_write_processing (bfd
*abfd
,
213 bfd_boolean linker ATTRIBUTE_UNUSED
)
216 struct bfd_elf_section_data
*d
;
218 sec
= bfd_get_section_by_name (abfd
, ".rel.plt.unloaded");
220 sec
= bfd_get_section_by_name (abfd
, ".rela.plt.unloaded");
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");
227 d
->this_hdr
.sh_info
= elf_section_data (sec
)->this_idx
;
230 /* Add the dynamic entries required by VxWorks. These point to the
234 elf_vxworks_add_dynamic_entries (bfd
*output_bfd
, struct bfd_link_info
*info
)
236 if (bfd_get_section_by_name (output_bfd
, ".tls_data"))
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))
243 if (bfd_get_section_by_name (output_bfd
, ".tls_vars"))
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))
252 /* If *DYN is one of the VxWorks-specific dynamic entries, then fill
253 in the value now and return TRUE. Otherwise return FALSE. */
256 elf_vxworks_finish_dynamic_entry (bfd
*output_bfd
, Elf_Internal_Dyn
*dyn
)
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
;
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
;
275 case DT_VX_WRS_TLS_DATA_ALIGN
:
276 sec
= bfd_get_section_by_name (output_bfd
, ".tls_data");
278 = (bfd_size_type
)1 << bfd_get_section_alignment (abfd
, sec
);
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
;
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
;