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;
}
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;
}
if (!bfd_link_pic (info))
*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;
}
bfd_boolean
_bfd_elf_create_ifunc_sections (bfd *abfd, struct bfd_link_info *info)
{
flagword flags, pltflags;
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->irelifunc != NULL || htab->iplt != NULL)
return TRUE;
flags = bed->dynamic_sec_flags;
pltflags = flags;
if (bed->plt_not_loaded)
/* We do not clear SEC_ALLOC here because we still want the OS to
allocate space for the section; it's just that there's nothing
to read in from the object file. */
pltflags &= ~ (SEC_CODE | SEC_LOAD | SEC_HAS_CONTENTS);
else
pltflags |= SEC_ALLOC | SEC_CODE | SEC_LOAD;
if (bed->plt_readonly)
pltflags |= SEC_READONLY;
if (bfd_link_pic (info))
{
/* We need to create .rel[a].ifunc for shared objects. */
const char *rel_sec = (bed->rela_plts_and_copies_p
? ".rela.ifunc" : ".rel.ifunc");
s = bfd_make_section_with_flags (abfd, rel_sec,
flags | SEC_READONLY);
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s,
bed->s->log_file_align))
return FALSE;
htab->irelifunc = s;
}
else
{
/* We need to create .iplt, .rel[a].iplt, .igot and .igot.plt
for static executables. */
s = bfd_make_section_with_flags (abfd, ".iplt", pltflags);
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s, bed->plt_alignment))
return FALSE;
htab->iplt = s;
s = bfd_make_section_with_flags (abfd,
(bed->rela_plts_and_copies_p
? ".rela.iplt" : ".rel.iplt"),
flags | SEC_READONLY);
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s,
bed->s->log_file_align))
return FALSE;
htab->irelplt = s;
/* We don't need the .igot section if we have the .igot.plt
section. */
if (bed->want_got_plt)
s = bfd_make_section_with_flags (abfd, ".igot.plt", flags);
else
s = bfd_make_section_with_flags (abfd, ".igot", flags);
if (s == NULL
|| !bfd_set_section_alignment (abfd, s,
bed->s->log_file_align))
return FALSE;
htab->igotplt = s;
}
return TRUE;
}
bfd_boolean
_bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
struct elf_link_hash_entry *h,
struct elf_dyn_relocs **head,
unsigned int plt_entry_size,
unsigned int plt_header_size,
unsigned int got_entry_size)
{
asection *plt, *gotplt, *relplt;
struct elf_dyn_relocs *p;
unsigned int sizeof_reloc;
const struct elf_backend_data *bed;
struct elf_link_hash_table *htab;
/* When a shared library references a STT_GNU_IFUNC symbol defined
in executable, the address of the resolved function may be used.
But in non-shared executable, the address of its .plt slot may
be used. Pointer equality may not work correctly. PIE should
be used if pointer equality is required here. */
if (!bfd_link_pic (info)
&& (h->dynindx != -1
|| info->export_dynamic)
&& h->pointer_equality_needed)
{
info->callbacks->einfo
(_("%F%P: dynamic STT_GNU_IFUNC symbol `%s' with pointer "
"equality in `%B' can not be used when making an "
"executable; recompile with -fPIE and relink with -pie\n"),
h->root.root.string,
h->root.u.def.section->owner);
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
htab = elf_hash_table (info);
/* When building shared library, we need to handle the case where it is
marked with regular reference, but not non-GOT reference since the
non-GOT reference bit may not be set here. */
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;
}
/* Support garbage collection against STT_GNU_IFUNC symbols. */
if (h->plt.refcount <= 0 && h->got.refcount <= 0)
{
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:
bed = get_elf_backend_data (info->output_bfd);
if (bed->rela_plts_and_copies_p)
sizeof_reloc = bed->s->sizeof_rela;
else
sizeof_reloc = bed->s->sizeof_rel;
/* When building a static executable, use .iplt, .igot.plt and
.rel[a].iplt sections for STT_GNU_IFUNC symbols. */
if (htab->splt != NULL)
{
plt = htab->splt;
gotplt = htab->sgotplt;
relplt = htab->srelplt;
/* If this is the first .plt entry, make room for the special
first entry. */
if (plt->size == 0)
plt->size += plt_header_size;
}
else
{
plt = htab->iplt;
gotplt = htab->igotplt;
relplt = htab->irelplt;
}
/* Don't update value of STT_GNU_IFUNC symbol to PLT. We need
the original value for R_*_IRELATIVE. */
h->plt.offset = plt->size;
/* Make room for this entry in the .plt/.iplt section. */
plt->size += plt_entry_size;
/* We also need to make an entry in the .got.plt/.got.iplt section,
which will be placed in the .got section by the linker script. */
gotplt->size += got_entry_size;
/* We also need to make an entry in the .rel[a].plt/.rel[a].iplt
section. */
relplt->size += sizeof_reloc;
relplt->reloc_count++;
/* 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 * sizeof_reloc;
}
/* For STT_GNU_IFUNC symbol, .got.plt has the real function address
and .got has the PLT entry adddress. We will load the GOT entry
with the PLT entry in finish_dynamic_symbol if it is used. For
branch, it uses .got.plt. For symbol value,
1. Use .got.plt in a shared object if it is forced local or not
dynamic.
2. Use .got.plt in a non-shared object if pointer equality isn't
needed.
3. Use .got.plt in PIE.
4. Use .got.plt if .got isn't used.
5. Otherwise use .got so that it can be shared among different
objects at run-time.
We only need to relocate .got entry in shared object. */
if (h->got.refcount <= 0
|| (bfd_link_pic (info)
&& (h->dynindx == -1
|| h->forced_local))
|| (!bfd_link_pic (info)
&& !h->pointer_equality_needed)
|| bfd_link_pie (info)
|| htab->sgot == NULL)
{
/* Use .got.plt. */
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 += sizeof_reloc;
}
return TRUE;
}
