1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
|
/* IBM S/390-specific support for ELF 32 and 64 bit functions
Copyright (C) 2000-2015 Free Software Foundation, Inc.
Contributed by Andreas Krebbel.
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., 51 Franklin Street - Fifth Floor, Boston, MA
02110-1301, USA. */
/* Return TRUE if H is an IFUNC symbol. Simply checking for the
symbol type might not be enough since it might get changed to
STT_FUNC for pointer equality reasons. */
static inline bfd_boolean
s390_is_ifunc_symbol_p (struct elf_link_hash_entry *h)
{
struct elf_s390_link_hash_entry *eh = (struct elf_s390_link_hash_entry*)h;
return h->type == STT_GNU_IFUNC || eh->ifunc_resolver_address != 0;
}
/* Create sections needed by STT_GNU_IFUNC symbol. */
static bfd_boolean
s390_elf_create_ifunc_sections (bfd *abfd, struct bfd_link_info *info)
{
flagword flags;
asection *s;
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
struct elf_link_hash_table *htab = elf_hash_table (info);
if (htab->iplt != NULL)
return TRUE;
flags = bed->dynamic_sec_flags;
if (bfd_link_pic (info))
{
s = bfd_make_section_with_flags (abfd, ".rela.ifunc",
flags | SEC_READONLY);
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s,
bed->s->log_file_align))
return FALSE;
htab->irelifunc = s;
}
/* Create .iplt, .rel[a].iplt, and .igot.plt. */
s = bfd_make_section_with_flags (abfd, ".iplt",
flags | SEC_CODE | SEC_READONLY);
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s, bed->plt_alignment))
return FALSE;
htab->iplt = s;
s = bfd_make_section_with_flags (abfd, ".rela.iplt", flags | SEC_READONLY);
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s,
bed->s->log_file_align))
return FALSE;
htab->irelplt = s;
s = bfd_make_section_with_flags (abfd, ".igot.plt", flags);
if (s == NULL
|| !bfd_set_section_alignment (abfd, s,
bed->s->log_file_align))
return FALSE;
htab->igotplt = s;
return TRUE;
}
/* Allocate space in .plt, .got and associated reloc sections for
dynamic relocs against a STT_GNU_IFUNC symbol definition. */
static bfd_boolean
s390_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
struct elf_dyn_relocs *p;
struct elf_link_hash_table *htab;
struct elf_s390_link_hash_entry *eh = (struct elf_s390_link_hash_entry*)h;
struct elf_dyn_relocs **head = &eh->dyn_relocs;
htab = elf_hash_table (info);
eh->ifunc_resolver_address = h->root.u.def.value;
eh->ifunc_resolver_section = h->root.u.def.section;
/* Support garbage collection against STT_GNU_IFUNC symbols. */
if (h->plt.refcount <= 0 && h->got.refcount <= 0)
{
/* When building shared library, we need to handle the case
where it is marked with regular reference, but not non-GOT
reference. It may happen if we didn't see STT_GNU_IFUNC
symbol at the time when checking relocations. */
if (bfd_link_pic (info)
&& !h->non_got_ref
&& h->ref_regular)
for (p = *head; p != NULL; p = p->next)
if (p->count)
{
h->non_got_ref = 1;
goto keep;
}
h->got = htab->init_got_offset;
h->plt = htab->init_plt_offset;
*head = NULL;
return TRUE;
}
/* Return and discard space for dynamic relocations against it if
it is never referenced in a non-shared object. */
if (!h->ref_regular)
{
if (h->plt.refcount > 0
|| h->got.refcount > 0)
abort ();
h->got = htab->init_got_offset;
h->plt = htab->init_plt_offset;
*head = NULL;
return TRUE;
}
keep:
/* Without checking h->plt.refcount here we allocate a PLT slot.
When setting plt.refcount in check_relocs it might not have been
known that this will be an IFUNC symol. */
h->plt.offset = htab->iplt->size;
h->needs_plt = 1;
htab->iplt->size += PLT_ENTRY_SIZE;
htab->igotplt->size += GOT_ENTRY_SIZE;
htab->irelplt->size += RELA_ENTRY_SIZE;
htab->irelplt->reloc_count++;
/* In order to make pointer equality work with IFUNC symbols defined
in a non-PIE executable and referenced in a shared lib, we turn
the symbol into a STT_FUNC symbol and make the symbol value to
point to the IPLT slot. That way the referencing shared lib will
always get the PLT slot address when resolving the respective
R_390_GLOB_DAT/R_390_64 relocs on that symbol. */
if (bfd_link_pde (info)
&& h->def_regular
&& h->ref_dynamic)
{
h->root.u.def.section = htab->iplt;
h->root.u.def.value = h->plt.offset;
h->size = PLT_ENTRY_SIZE;
h->type = STT_FUNC;
}
/* We need dynamic relocation for STT_GNU_IFUNC symbol only when
there is a non-GOT reference in a shared object. */
if (!bfd_link_pic (info) || !h->non_got_ref)
*head = NULL;
/* Finally, allocate space. */
p = *head;
if (p != NULL)
{
bfd_size_type count = 0;
do
{
count += p->count;
p = p->next;
}
while (p != NULL);
htab->irelifunc->size += count * RELA_ENTRY_SIZE;
}
/* Decide whether the got.iplt slot can be used. This has to be
avoided if the values in the GOT slots could differ for pointer
equality reasons. */
if (h->got.refcount <= 0
|| (bfd_link_pic (info)
&& (h->dynindx == -1 || h->forced_local))
|| bfd_link_pie (info)
|| htab->sgot == NULL)
{
/* Use .got.iplt. */
h->got.offset = (bfd_vma) -1;
}
else
{
h->got.offset = htab->sgot->size;
htab->sgot->size += GOT_ENTRY_SIZE;
if (bfd_link_pic (info))
htab->srelgot->size += RELA_ENTRY_SIZE;
}
return TRUE;
}
static bfd_boolean
elf_s390_allocate_local_syminfo (bfd *abfd, Elf_Internal_Shdr *symtab_hdr)
{
bfd_size_type size;
size = symtab_hdr->sh_info;
size *= (sizeof (bfd_signed_vma) /* local got */
+ sizeof (struct plt_entry) /* local plt */
+ sizeof(char)); /* local tls type */
elf_local_got_refcounts (abfd) = ((bfd_signed_vma *)
bfd_zalloc (abfd, size));
if (elf_local_got_refcounts (abfd) == NULL)
return FALSE;
elf_s390_local_plt (abfd)
= (struct plt_entry*)(elf_local_got_refcounts (abfd)
+ symtab_hdr->sh_info);
elf_s390_local_got_tls_type (abfd)
= (char *) (elf_s390_local_plt (abfd) + symtab_hdr->sh_info);
return TRUE;
}
/* Pick ELFOSABI_GNU if IFUNC symbols are used. */
static bfd_boolean
elf_s390_add_symbol_hook (bfd *abfd,
struct bfd_link_info *info,
Elf_Internal_Sym *sym,
const char **namep ATTRIBUTE_UNUSED,
flagword *flagsp ATTRIBUTE_UNUSED,
asection **secp ATTRIBUTE_UNUSED,
bfd_vma *valp ATTRIBUTE_UNUSED)
{
if ((ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
|| ELF_ST_BIND (sym->st_info) == STB_GNU_UNIQUE)
&& (abfd->flags & DYNAMIC) == 0
&& bfd_get_flavour (info->output_bfd) == bfd_target_elf_flavour)
elf_tdata (info->output_bfd)->has_gnu_symbols = elf_gnu_symbol_any;
return TRUE;
}
/* Whether to sort relocs output by ld -r or ld --emit-relocs, by
r_offset. Don't do so for code sections. We want to keep ordering
of GDCALL / PLT32DBL for TLS optimizations as is. On the other
hand, elf-eh-frame.c processing requires .eh_frame relocs to be
sorted. */
static bfd_boolean
elf_s390_elf_sort_relocs_p (asection *sec)
{
return (sec->flags & SEC_CODE) == 0;
}
/* Merge object attributes from IBFD into OBFD. Raise an error if
there are conflicting attributes. */
static bfd_boolean
elf_s390_merge_obj_attributes (bfd *ibfd, bfd *obfd)
{
obj_attribute *in_attr, *in_attrs;
obj_attribute *out_attr, *out_attrs;
if (!elf_known_obj_attributes_proc (obfd)[0].i)
{
/* This is the first object. Copy the attributes. */
_bfd_elf_copy_obj_attributes (ibfd, obfd);
/* Use the Tag_null value to indicate the attributes have been
initialized. */
elf_known_obj_attributes_proc (obfd)[0].i = 1;
return TRUE;
}
in_attrs = elf_known_obj_attributes (ibfd)[OBJ_ATTR_GNU];
out_attrs = elf_known_obj_attributes (obfd)[OBJ_ATTR_GNU];
/* Check for conflicting Tag_GNU_S390_ABI_Vector attributes and
merge non-conflicting ones. */
in_attr = &in_attrs[Tag_GNU_S390_ABI_Vector];
out_attr = &out_attrs[Tag_GNU_S390_ABI_Vector];
if (in_attr->i > 2)
_bfd_error_handler
(_("Warning: %B uses unknown vector ABI %d"), ibfd,
in_attr->i);
else if (out_attr->i > 2)
_bfd_error_handler
(_("Warning: %B uses unknown vector ABI %d"), obfd,
out_attr->i);
else if (in_attr->i != out_attr->i)
{
out_attr->type = ATTR_TYPE_FLAG_INT_VAL;
if (in_attr->i && out_attr->i)
{
const char abi_str[3][9] = { "none", "software", "hardware" };
_bfd_error_handler
(_("Warning: %B uses vector %s ABI, %B uses %s ABI"),
ibfd, obfd, abi_str[in_attr->i], abi_str[out_attr->i]);
}
if (in_attr->i > out_attr->i)
out_attr->i = in_attr->i;
}
/* Merge Tag_compatibility attributes and any common GNU ones. */
_bfd_elf_merge_object_attributes (ibfd, obfd);
return TRUE;
}
|