summaryrefslogtreecommitdiff
path: root/bfd/elf32-s390.c
diff options
context:
space:
mode:
authorAndreas Krebbel <Andreas.Krebbel@de.ibm.com>2012-07-13 15:47:21 +0000
committerAndreas Krebbel <Andreas.Krebbel@de.ibm.com>2012-07-13 15:47:21 +0000
commitfa7d23d17b37e43b92bbe1754daab12de8748129 (patch)
tree28330d6c369b24a2d0a923de13f48626341d1e20 /bfd/elf32-s390.c
parent42e7428f49b3b94658767b4ce634bd307968749e (diff)
downloadbinutils-redhat-fa7d23d17b37e43b92bbe1754daab12de8748129.tar.gz
2012-07-13 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
* elf64-s390.c: Include elf-s390-common.c. (R_390_IRELATIVE): New reloc. (elf_s390_reloc_type_lookup): Support R_390_IRELATIVE. (RELA_ENTRY_SIZE): New macro. (elf_s390_link_hash_entry): New fields ifunc_resolver_address and *ifunc_resolver_section. (struct plt_entry): New struct. (struct elf_s390_obj_tdata): New field local_plt. (elf_s390_local_plt): New macro. (struct elf_s390_link_hash_table): New field irelifunc. (ELF64): New macro. (link_hash_newfunc): Initialize new fields. (elf_s390_check_relocs): Handle IFUNC symbols. (elf_s390_adjust_dynamic_symbol): Don't do anything for IFUNC symbols. (allocate_dynrelocs): Call s390_elf_allocate_ifunc_dyn_relocs for IFUNC symbols. (elf_s390_size_dynamic_sections): Handle IFUNC symbols. (elf_s390_relocate_section): Likewise. (elf_s390_finish_dynamic_symbol): Likewise. (elf_s390_finish_dynamic_sections): Handle local IFUNC symbols. (elf_s390_finish_ifunc_symbol): New function. (elf_s390_gc_sweep_hook): Handle local plt entries. (elf_backend_add_symbol_hook): Define. * elf32-s390.c: See elf64-s390.c changes. * elf-s390-common.c: New file. * bfd-in2.h (BFD_RELOC_390_IRELATIVE): New enum field. * libbfd.h (BFD_RELOC_390_IRELATIVE): New entry for BFD_RELOC_390_IRELATIVE. * reloc.c (BFD_RELOC_390_IRELATIVE): Document new relocation. 2012-07-13 Andreas Krebbel <Andreas.Krebbel@de.ibm.com> * elf/s390.h (START_RELOC_NUMBERS): Define R_390_IRELATIVE reloc. 2012-07-13 Andreas Krebbel <Andreas.Krebbel@de.ibm.com> * emulparams/elf_s390.sh (IREL_IN_PLT): Define. * emulparams/elf64_s390.sh (IREL_IN_PLT): Define.
Diffstat (limited to 'bfd/elf32-s390.c')
-rw-r--r--bfd/elf32-s390.c827
1 files changed, 664 insertions, 163 deletions
diff --git a/bfd/elf32-s390.c b/bfd/elf32-s390.c
index cbf768df42..8d654d5486 100644
--- a/bfd/elf32-s390.c
+++ b/bfd/elf32-s390.c
@@ -159,6 +159,8 @@ static reloc_howto_type elf_howto_table[] =
s390_elf_ldisp_reloc, "R_390_GOTPLT20", FALSE, 0,0x0fffff00, FALSE),
HOWTO(R_390_TLS_GOTIE20, 0, 2, 20, FALSE, 8, complain_overflow_dont,
s390_elf_ldisp_reloc, "R_390_TLS_GOTIE20", FALSE, 0,0x0fffff00, FALSE),
+ HOWTO(R_390_IRELATIVE, 0, 2, 32, TRUE, 0, complain_overflow_bitfield,
+ bfd_elf_generic_reloc, "R_390_IRELATIVE", FALSE, 0, 0xffffffff, FALSE),
};
/* GNU extension to record C++ vtable hierarchy. */
@@ -271,6 +273,8 @@ elf_s390_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
return &elf_howto_table[(int) R_390_GOTPLT20];
case BFD_RELOC_390_TLS_GOTIE20:
return &elf_howto_table[(int) R_390_TLS_GOTIE20];
+ case BFD_RELOC_390_IRELATIVE:
+ return &elf_howto_table[(int) R_390_IRELATIVE];
case BFD_RELOC_VTABLE_INHERIT:
return &elf32_s390_vtinherit_howto;
case BFD_RELOC_VTABLE_ENTRY:
@@ -425,6 +429,8 @@ elf_s390_is_local_label_name (bfd *abfd, const char *name)
#define GOT_ENTRY_SIZE 4
+#define RELA_ENTRY_SIZE sizeof (Elf32_External_Rela)
+
/* The first three entries in a procedure linkage table are reserved,
and the initial contents are unimportant (we zero them out).
Subsequent entries look like this. See the SVR4 ABI 386
@@ -639,17 +645,43 @@ struct elf_s390_link_hash_entry
#define GOT_TLS_IE 3
#define GOT_TLS_IE_NLT 4
unsigned char tls_type;
+
+ /* For pointer equality reasons we might need to change the symbol
+ type from STT_GNU_IFUNC to STT_FUNC together with its value and
+ section entry. So after alloc_dynrelocs only these values should
+ be used. In order to check whether a symbol is IFUNC use
+ s390_is_ifunc_symbol_p. */
+ bfd_vma ifunc_resolver_address;
+ asection *ifunc_resolver_section;
};
#define elf_s390_hash_entry(ent) \
((struct elf_s390_link_hash_entry *)(ent))
+/* This structure represents an entry in the local PLT list needed for
+ local IFUNC symbols. */
+struct plt_entry
+{
+ /* The section of the local symbol.
+ Set in relocate_section and used in finish_dynamic_sections. */
+ asection *sec;
+
+ union
+ {
+ bfd_signed_vma refcount;
+ bfd_vma offset;
+ } plt;
+};
+
/* NOTE: Keep this structure in sync with
the one declared in elf64-s390.c. */
struct elf_s390_obj_tdata
{
struct elf_obj_tdata root;
+ /* A local PLT is needed for ifunc symbols. */
+ struct plt_entry *local_plt;
+
/* TLS type for each local got entry. */
char *local_got_tls_type;
};
@@ -657,6 +689,9 @@ struct elf_s390_obj_tdata
#define elf_s390_tdata(abfd) \
((struct elf_s390_obj_tdata *) (abfd)->tdata.any)
+#define elf_s390_local_plt(abfd) \
+ (elf_s390_tdata (abfd)->local_plt)
+
#define elf_s390_local_got_tls_type(abfd) \
(elf_s390_tdata (abfd)->local_got_tls_type)
@@ -688,6 +723,7 @@ struct elf_s390_link_hash_table
/* Short-cuts to get to dynamic linker sections. */
asection *sdynbss;
asection *srelbss;
+ asection *irelifunc;
union
{
@@ -705,6 +741,9 @@ struct elf_s390_link_hash_table
(elf_hash_table_id ((struct elf_link_hash_table *) ((p)->hash)) \
== S390_ELF_DATA ? ((struct elf_s390_link_hash_table *) ((p)->hash)) : NULL)
+#undef ELF64
+#include "elf-s390-common.c"
+
/* Create an entry in an s390 ELF linker hash table. */
static struct bfd_hash_entry *
@@ -732,6 +771,8 @@ link_hash_newfunc (struct bfd_hash_entry *entry,
eh->dyn_relocs = NULL;
eh->gotplt_refcount = 0;
eh->tls_type = GOT_UNKNOWN;
+ eh->ifunc_resolver_address = 0;
+ eh->ifunc_resolver_section = NULL;
}
return entry;
@@ -930,6 +971,7 @@ elf_s390_check_relocs (bfd *abfd,
asection *sreloc;
bfd_signed_vma *local_got_refcounts;
int tls_type, old_tls_type;
+ Elf_Internal_Sym *isym;
if (info->relocatable)
return TRUE;
@@ -960,7 +1002,31 @@ elf_s390_check_relocs (bfd *abfd,
}
if (r_symndx < symtab_hdr->sh_info)
- h = NULL;
+ {
+ /* A local symbol. */
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache,
+ abfd, r_symndx);
+ if (isym == NULL)
+ return FALSE;
+
+ if (ELF_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
+ {
+ struct plt_entry *plt;
+
+ if (!s390_elf_create_ifunc_sections (htab->elf.dynobj, info))
+ return FALSE;
+
+ if (local_got_refcounts == NULL)
+ {
+ if (!elf_s390_allocate_local_syminfo (abfd, symtab_hdr))
+ return FALSE;
+ local_got_refcounts = elf_local_got_refcounts (abfd);
+ }
+ plt = elf_s390_local_plt (abfd);
+ plt[r_symndx].plt.refcount++;
+ }
+ h = NULL;
+ }
else
{
h = sym_hashes[r_symndx - symtab_hdr->sh_info];
@@ -996,17 +1062,9 @@ elf_s390_check_relocs (bfd *abfd,
if (h == NULL
&& local_got_refcounts == NULL)
{
- bfd_size_type size;
-
- size = symtab_hdr->sh_info;
- size *= (sizeof (bfd_signed_vma) + sizeof(char));
- local_got_refcounts = ((bfd_signed_vma *)
- bfd_zalloc (abfd, size));
- if (local_got_refcounts == NULL)
+ if (!elf_s390_allocate_local_syminfo (abfd, symtab_hdr))
return FALSE;
- elf_local_got_refcounts (abfd) = local_got_refcounts;
- elf_s390_local_got_tls_type (abfd)
- = (char *) (local_got_refcounts + symtab_hdr->sh_info);
+ local_got_refcounts = elf_local_got_refcounts (abfd);
}
/* Fall through. */
case R_390_GOTOFF16:
@@ -1022,13 +1080,34 @@ elf_s390_check_relocs (bfd *abfd,
}
}
+ if (h != NULL)
+ {
+ if (htab->elf.dynobj == NULL)
+ htab->elf.dynobj = abfd;
+ if (!s390_elf_create_ifunc_sections (htab->elf.dynobj, info))
+ return FALSE;
+
+ /* Make sure an IFUNC symbol defined in a non-shared object
+ always gets a PLT slot. */
+ if (s390_is_ifunc_symbol_p (h) && h->def_regular)
+ {
+ /* The symbol is called by the dynamic loader in order
+ to resolve the relocation. So it is in fact also
+ referenced. */
+ h->ref_regular = 1;
+ h->needs_plt = 1;
+ }
+ }
switch (r_type)
{
case R_390_GOTOFF16:
case R_390_GOTOFF32:
case R_390_GOTPC:
case R_390_GOTPCDBL:
- /* Got is created, nothing to be done. */
+ /* These relocs do not need a GOT slot. They just load the
+ GOT pointer itself or address something else relative to
+ the GOT. Since the GOT pointer has been set up above we
+ are done. */
break;
case R_390_PLT16DBL:
@@ -1169,7 +1248,7 @@ elf_s390_check_relocs (bfd *abfd,
case R_390_PC16DBL:
case R_390_PC32DBL:
case R_390_PC32:
- if (h != NULL && !info->shared)
+ if (h != NULL)
{
/* If this reloc is in a read-only section, we might
need a copy reloc. We can't check reliably at this
@@ -1179,9 +1258,12 @@ elf_s390_check_relocs (bfd *abfd,
adjust_dynamic_symbol. */
h->non_got_ref = 1;
- /* We may need a .plt entry if the function this reloc
- refers to is in a shared lib. */
- h->plt.refcount += 1;
+ if (!info->shared)
+ {
+ /* We may need a .plt entry if the function this reloc
+ refers to is in a shared lib. */
+ h->plt.refcount += 1;
+ }
}
/* If we are creating a shared library, and this is a reloc
@@ -1253,7 +1335,6 @@ elf_s390_check_relocs (bfd *abfd,
easily. Oh well. */
asection *s;
void *vpp;
- Elf_Internal_Sym *isym;
isym = bfd_sym_from_r_symndx (&htab->sym_cache,
abfd, r_symndx);
@@ -1346,6 +1427,7 @@ elf_s390_gc_sweep_hook (bfd *abfd,
asection *sec,
const Elf_Internal_Rela *relocs)
{
+ struct elf_s390_link_hash_table *htab;
Elf_Internal_Shdr *symtab_hdr;
struct elf_link_hash_entry **sym_hashes;
bfd_signed_vma *local_got_refcounts;
@@ -1354,6 +1436,10 @@ elf_s390_gc_sweep_hook (bfd *abfd,
if (info->relocatable)
return TRUE;
+ htab = elf_s390_hash_table (info);
+ if (htab == NULL)
+ return FALSE;
+
elf_section_data (sec)->local_dynrel = NULL;
symtab_hdr = &elf_symtab_hdr (abfd);
@@ -1388,6 +1474,23 @@ elf_s390_gc_sweep_hook (bfd *abfd,
break;
}
}
+ else
+ {
+ Elf_Internal_Sym *isym;
+
+ /* A local symbol. */
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache,
+ abfd, r_symndx);
+ if (isym == NULL)
+ return FALSE;
+
+ if (ELF_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
+ {
+ struct plt_entry *plt = elf_s390_local_plt (abfd);
+ if (plt[r_symndx].plt.refcount > 0)
+ plt[r_symndx].plt.refcount--;
+ }
+ }
r_type = ELF32_R_TYPE (rel->r_info);
r_type = elf_s390_tls_transition (info, r_type, h != NULL);
@@ -1513,6 +1616,10 @@ elf_s390_adjust_dynamic_symbol (struct bfd_link_info *info,
struct elf_s390_link_hash_table *htab;
asection *s;
+ /* STT_GNU_IFUNC symbol must go through PLT. */
+ if (s390_is_ifunc_symbol_p (h))
+ return TRUE;
+
/* If this is a function, put it in the procedure linkage table. We
will fill in the contents of the procedure linkage table later
(although we could actually do it here). */
@@ -1636,7 +1743,7 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
{
struct bfd_link_info *info;
struct elf_s390_link_hash_table *htab;
- struct elf_s390_link_hash_entry *eh;
+ struct elf_s390_link_hash_entry *eh = (struct elf_s390_link_hash_entry *)h;
struct elf_dyn_relocs *p;
if (h->root.type == bfd_link_hash_indirect)
@@ -1645,8 +1752,13 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
info = (struct bfd_link_info *) inf;
htab = elf_s390_hash_table (info);
- if (htab->elf.dynamic_sections_created
- && h->plt.refcount > 0)
+ /* Since STT_GNU_IFUNC symbol must go through PLT, we handle it
+ here if it is defined and referenced in a non-shared object. */
+ if (s390_is_ifunc_symbol_p (h) && h->def_regular)
+ return s390_elf_allocate_ifunc_dyn_relocs (info, h,
+ &eh->dyn_relocs);
+ else if (htab->elf.dynamic_sections_created
+ && h->plt.refcount > 0)
{
/* Make sure this symbol is output as a dynamic symbol.
Undefined weak syms won't yet be marked as dynamic. */
@@ -1763,7 +1875,6 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
else
h->got.offset = (bfd_vma) -1;
- eh = (struct elf_s390_link_hash_entry *) h;
if (eh->dyn_relocs == NULL)
return TRUE;
@@ -1918,6 +2029,8 @@ elf_s390_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
bfd_size_type locsymcount;
Elf_Internal_Shdr *symtab_hdr;
asection *srela;
+ struct plt_entry *local_plt;
+ unsigned int i;
if (! is_s390_elf (ibfd))
continue;
@@ -1970,6 +2083,19 @@ elf_s390_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
else
*local_got = (bfd_vma) -1;
}
+ local_plt = elf_s390_local_plt (ibfd);
+ for (i = 0; i < symtab_hdr->sh_info; i++)
+ {
+ if (local_plt[i].plt.refcount > 0)
+ {
+ local_plt[i].plt.offset = htab->elf.iplt->size;
+ htab->elf.iplt->size += PLT_ENTRY_SIZE;
+ htab->elf.igotplt->size += GOT_ENTRY_SIZE;
+ htab->elf.irelplt->size += RELA_ENTRY_SIZE;
+ }
+ else
+ local_plt[i].plt.offset = (bfd_vma) -1;
+ }
}
if (htab->tls_ldm_got.refcount > 0)
@@ -1998,7 +2124,10 @@ elf_s390_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
if (s == htab->elf.splt
|| s == htab->elf.sgot
|| s == htab->elf.sgotplt
- || s == htab->sdynbss)
+ || s == htab->sdynbss
+ || s == htab->elf.iplt
+ || s == htab->elf.igotplt
+ || s == htab->irelifunc)
{
/* Strip this section if we don't need it; see the
comment below. */
@@ -2184,6 +2313,7 @@ elf_s390_relocate_section (bfd *output_bfd,
bfd_boolean unresolved_reloc;
bfd_reloc_status_type r;
int tls_type;
+ asection *base_got = htab->elf.sgot;
r_type = ELF32_R_TYPE (rel->r_info);
if (r_type == (int) R_390_GNU_VTINHERIT
@@ -2206,7 +2336,52 @@ elf_s390_relocate_section (bfd *output_bfd,
{
sym = local_syms + r_symndx;
sec = local_sections[r_symndx];
- relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);
+ if (ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC)
+ {
+ struct plt_entry *local_plt = elf_s390_local_plt (input_bfd);
+ if (local_plt == NULL)
+ return FALSE;
+
+ /* Address of the PLT slot. */
+ relocation = (htab->elf.iplt->output_section->vma
+ + htab->elf.iplt->output_offset
+ + local_plt[r_symndx].plt.offset);
+
+ switch (r_type)
+ {
+ case R_390_GOTPLT12:
+ case R_390_GOTPLT16:
+ case R_390_GOTPLT20:
+ case R_390_GOTPLT32:
+ case R_390_GOTPLTENT:
+ case R_390_GOT12:
+ case R_390_GOT16:
+ case R_390_GOT20:
+ case R_390_GOT32:
+ case R_390_GOTENT:
+ {
+ /* Write the PLT slot address into the GOT slot. */
+ bfd_put_32 (output_bfd, relocation,
+ htab->elf.sgot->contents +
+ local_got_offsets[r_symndx]);
+ relocation = (local_got_offsets[r_symndx] +
+ htab->elf.sgot->output_offset);
+
+ if (r_type == R_390_GOTENT || r_type == R_390_GOTPLTENT)
+ relocation += htab->elf.sgot->output_section->vma;
+ break;
+ }
+ default:
+ break;
+ }
+ /* The output section is needed later in
+ finish_dynamic_section when creating the dynamic
+ relocation. */
+ local_plt[r_symndx].sec = sec;
+ goto do_relocation;
+ }
+ else
+ relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);
}
else
{
@@ -2245,19 +2420,29 @@ elf_s390_relocate_section (bfd *output_bfd,
{
bfd_vma plt_index;
- /* Calc. index no.
- Current offset - size first entry / entry size. */
- plt_index = (h->plt.offset - PLT_FIRST_ENTRY_SIZE) /
- PLT_ENTRY_SIZE;
-
- /* Offset in GOT is PLT index plus GOT headers(3) times 4,
- addr & GOT addr. */
- relocation = (plt_index + 3) * GOT_ENTRY_SIZE;
+ if (s390_is_ifunc_symbol_p (h))
+ {
+ plt_index = h->plt.offset / PLT_ENTRY_SIZE;
+ relocation = (plt_index * GOT_ENTRY_SIZE +
+ htab->elf.igotplt->output_offset);
+ if (r_type == R_390_GOTPLTENT)
+ relocation += htab->elf.igotplt->output_section->vma;
+ }
+ else
+ {
+ /* Calc. index no.
+ Current offset - size first entry / entry size. */
+ plt_index = (h->plt.offset - PLT_FIRST_ENTRY_SIZE) /
+ PLT_ENTRY_SIZE;
+
+ /* Offset in GOT is PLT index plus GOT headers(3)
+ times 4, addr & GOT addr. */
+ relocation = (plt_index + 3) * GOT_ENTRY_SIZE;
+ if (r_type == R_390_GOTPLTENT)
+ relocation += htab->elf.sgot->output_section->vma;
+ }
unresolved_reloc = FALSE;
- if (r_type == R_390_GOTPLTENT)
- relocation += htab->elf.sgot->output_section->vma;
- break;
}
/* Fall through. */
@@ -2268,7 +2453,7 @@ elf_s390_relocate_section (bfd *output_bfd,
case R_390_GOTENT:
/* Relocation is to the entry for this symbol in the global
offset table. */
- if (htab->elf.sgot == NULL)
+ if (base_got == NULL)
abort ();
if (h != NULL)
@@ -2277,11 +2462,30 @@ elf_s390_relocate_section (bfd *output_bfd,
off = h->got.offset;
dyn = htab->elf.dynamic_sections_created;
- if (! WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, info->shared, h)
- || (info->shared
- && SYMBOL_REFERENCES_LOCAL (info, h))
- || (ELF_ST_VISIBILITY (h->other)
- && h->root.type == bfd_link_hash_undefweak))
+
+ if (s390_is_ifunc_symbol_p (h))
+ {
+ BFD_ASSERT (h->plt.offset != (bfd_vma) -1);
+ if (off == (bfd_vma)-1)
+ {
+ /* No explicit GOT usage so redirect to the
+ got.iplt slot. */
+ base_got = htab->elf.igotplt;
+ off = h->plt.offset / PLT_ENTRY_SIZE * GOT_ENTRY_SIZE;
+ }
+ else
+ {
+ /* Explicit GOT slots must contain the address
+ of the PLT slot. This will be handled in
+ finish_dynamic_symbol. */
+ }
+ }
+ else if (! WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, info->shared, h)
+ || (info->shared
+ && SYMBOL_REFERENCES_LOCAL (info, h))
+ || (ELF_ST_VISIBILITY (h->other)
+ && h->root.type == bfd_link_hash_undefweak))
+
{
/* This is actually a static link, or it is a
-Bsymbolic link and the symbol is defined
@@ -2300,7 +2504,7 @@ elf_s390_relocate_section (bfd *output_bfd,
else
{
bfd_put_32 (output_bfd, relocation,
- htab->elf.sgot->contents + off);
+ base_got->contents + off);
h->got.offset |= 1;
}
}
@@ -2351,7 +2555,7 @@ elf_s390_relocate_section (bfd *output_bfd,
if (off >= (bfd_vma) -2)
abort ();
- relocation = htab->elf.sgot->output_offset + off;
+ relocation = base_got->output_offset + off;
/* For @GOTENT the relocation is against the offset between
the instruction and the symbols entry in the GOT and not
@@ -2359,7 +2563,7 @@ elf_s390_relocate_section (bfd *output_bfd,
add the vma of the GOT to get the correct value. */
if ( r_type == R_390_GOTENT
|| r_type == R_390_GOTPLTENT)
- relocation += htab->elf.sgot->output_section->vma;
+ relocation += base_got->output_section->vma;
break;
@@ -2395,7 +2599,7 @@ elf_s390_relocate_section (bfd *output_bfd,
break;
if (h->plt.offset == (bfd_vma) -1
- || htab->elf.splt == NULL)
+ || (htab->elf.splt == NULL && htab->elf.iplt == NULL))
{
/* We didn't make a PLT entry for this symbol. This
happens when statically linking PIC code, or when
@@ -2403,9 +2607,14 @@ elf_s390_relocate_section (bfd *output_bfd,
break;
}
- relocation = (htab->elf.splt->output_section->vma
- + htab->elf.splt->output_offset
- + h->plt.offset);
+ if (s390_is_ifunc_symbol_p (h))
+ relocation = (htab->elf.iplt->output_section->vma
+ + htab->elf.iplt->output_offset
+ + h->plt.offset);
+ else
+ relocation = (htab->elf.splt->output_section->vma
+ + htab->elf.splt->output_offset
+ + h->plt.offset);
unresolved_reloc = FALSE;
break;
@@ -2424,10 +2633,16 @@ elf_s390_relocate_section (bfd *output_bfd,
break;
}
- relocation = (htab->elf.splt->output_section->vma
- + htab->elf.splt->output_offset
- + h->plt.offset
- - htab->elf.sgot->output_section->vma);
+ if (s390_is_ifunc_symbol_p (h))
+ relocation = (htab->elf.iplt->output_section->vma
+ + htab->elf.iplt->output_offset
+ + h->plt.offset
+ - htab->elf.sgot->output_section->vma);
+ else
+ relocation = (htab->elf.splt->output_section->vma
+ + htab->elf.splt->output_offset
+ + h->plt.offset
+ - htab->elf.sgot->output_section->vma);
unresolved_reloc = FALSE;
break;
@@ -2438,6 +2653,67 @@ elf_s390_relocate_section (bfd *output_bfd,
case R_390_PC16DBL:
case R_390_PC32DBL:
case R_390_PC32:
+ if (h != NULL
+ && s390_is_ifunc_symbol_p (h)
+ && h->def_regular)
+ {
+ if (!info->shared || !h->non_got_ref)
+ {
+ /* For a non-shared object STT_GNU_IFUNC symbol must
+ go through PLT. */
+ relocation = (htab->elf.iplt->output_section->vma
+ + htab->elf.iplt->output_offset
+ + h ->plt.offset);
+ goto do_relocation;
+ }
+ else
+ {
+ /* For shared objects a runtime relocation is needed. */
+
+ Elf_Internal_Rela outrel;
+ asection *sreloc;
+
+ /* Need a dynamic relocation to get the real function
+ address. */
+ outrel.r_offset = _bfd_elf_section_offset (output_bfd,
+ info,
+ input_section,
+ rel->r_offset);
+ if (outrel.r_offset == (bfd_vma) -1
+ || outrel.r_offset == (bfd_vma) -2)
+ abort ();
+
+ outrel.r_offset += (input_section->output_section->vma
+ + input_section->output_offset);
+
+ if (h->dynindx == -1
+ || h->forced_local
+ || info->executable)
+ {
+ /* This symbol is resolved locally. */
+ outrel.r_info = ELF32_R_INFO (0, R_390_IRELATIVE);
+ outrel.r_addend = (h->root.u.def.value
+ + h->root.u.def.section->output_section->vma
+ + h->root.u.def.section->output_offset);
+ }
+ else
+ {
+ outrel.r_info = ELF32_R_INFO (h->dynindx, r_type);
+ outrel.r_addend = 0;
+ }
+
+ sreloc = htab->elf.irelifunc;
+ elf_append_rela (output_bfd, sreloc, &outrel);
+
+ /* If this reloc is against an external symbol, we
+ do not want to fiddle with the addend. Otherwise,
+ we need to include the symbol value so that it
+ becomes an addend for the dynamic reloc. For an
+ internal symbol, we have updated addend. */
+ continue;
+ }
+ }
+
if ((input_section->flags & SEC_ALLOC) == 0)
break;
@@ -2963,6 +3239,8 @@ elf_s390_relocate_section (bfd *output_bfd,
howto->name,
h->root.root.string);
+ do_relocation:
+
if (r_type == R_390_20
|| r_type == R_390_GOT20
|| r_type == R_390_GOTPLT20
@@ -3019,6 +3297,152 @@ elf_s390_relocate_section (bfd *output_bfd,
return TRUE;
}
+/* Generate the PLT slots together with the dynamic relocations needed
+ for IFUNC symbols. */
+
+static void
+elf_s390_finish_ifunc_symbol (bfd *output_bfd,
+ struct bfd_link_info *info,
+ struct elf_link_hash_entry *h,
+ struct elf_s390_link_hash_table *htab,
+ bfd_vma iplt_offset,
+ bfd_vma resolver_address)
+{
+ bfd_vma iplt_index;
+ bfd_vma got_offset;
+ bfd_vma igotiplt_offset;
+ Elf_Internal_Rela rela;
+ bfd_byte *loc;
+ asection *plt, *gotplt, *relplt;
+ bfd_vma relative_offset;
+
+ if (htab->elf.iplt == NULL
+ || htab->elf.igotplt == NULL
+ || htab->elf.irelplt == NULL)
+ abort ();
+
+ gotplt = htab->elf.igotplt;
+ relplt = htab->elf.irelplt;
+
+ /* Index of the PLT slot within iplt section. */
+ iplt_index = iplt_offset / PLT_ENTRY_SIZE;
+ plt = htab->elf.iplt;
+ /* Offset into the igot.plt section. */
+ igotiplt_offset = iplt_index * GOT_ENTRY_SIZE;
+ /* Offset into the got section. */
+ got_offset = igotiplt_offset + gotplt->output_offset;
+
+ /* S390 uses halfwords for relative branch calc! */
+ relative_offset = - (plt->output_offset +
+ (PLT_ENTRY_SIZE * iplt_index) + 18) / 2;
+/* If offset is > 32768, branch to a previous branch
+ 390 can only handle +-64 K jumps. */
+ if ( -32768 > (int) relative_offset )
+ relative_offset
+ = -(unsigned) (((65536 / PLT_ENTRY_SIZE - 1) * PLT_ENTRY_SIZE) / 2);
+
+ /* Fill in the entry in the procedure linkage table. */
+ if (!info->shared)
+ {
+ memcpy (plt->contents + iplt_offset, elf_s390_plt_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Adjust jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ plt->contents + iplt_offset + 20);
+
+ /* Push the GOT offset field. */
+ bfd_put_32 (output_bfd,
+ (gotplt->output_section->vma
+ + got_offset),
+ plt->contents + iplt_offset + 24);
+ }
+ else if (got_offset < 4096)
+ {
+ /* The GOT offset is small enough to be used directly as
+ displacement. */
+ memcpy (plt->contents + iplt_offset,
+ elf_s390_plt_pic12_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Put in the GOT offset as displacement value. The 0xc000
+ value comes from the first word of the plt entry. Look
+ at the elf_s390_plt_pic16_entry content. */
+ bfd_put_16 (output_bfd, (bfd_vma)0xc000 | got_offset,
+ plt->contents + iplt_offset + 2);
+
+ /* Adjust the jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ plt->contents + iplt_offset + 20);
+ }
+ else if (got_offset < 32768)
+ {
+ /* The GOT offset is too big for a displacement but small
+ enough to be a signed 16 bit immediate value as it can be
+ used in an lhi instruction. */
+ memcpy (plt->contents + iplt_offset,
+ elf_s390_plt_pic16_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Put in the GOT offset for the lhi instruction. */
+ bfd_put_16 (output_bfd, (bfd_vma)got_offset,
+ plt->contents + iplt_offset + 2);
+
+ /* Adjust the jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ plt->contents + iplt_offset + 20);
+ }
+ else
+ {
+ memcpy (plt->contents + iplt_offset,
+ elf_s390_plt_pic_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Adjust the jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ plt->contents + iplt_offset + 20);
+
+ /* Push the GOT offset field. */
+ bfd_put_32 (output_bfd, got_offset,
+ plt->contents + iplt_offset + 24);
+ }
+ /* Insert offset into reloc. table here. */
+ bfd_put_32 (output_bfd, relplt->output_offset +
+ iplt_index * RELA_ENTRY_SIZE,
+ plt->contents + iplt_offset + 28);
+
+ /* Fill in the entry in the global offset table.
+ Points to instruction after GOT offset. */
+ bfd_put_32 (output_bfd,
+ (plt->output_section->vma
+ + plt->output_offset
+ + iplt_offset
+ + 12),
+ gotplt->contents + igotiplt_offset);
+
+ /* Fill in the entry in the .rela.plt section. */
+ rela.r_offset = gotplt->output_section->vma + got_offset;
+
+ if (!h
+ || h->dynindx == -1
+ || ((info->executable
+ || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT)
+ && h->def_regular))
+ {
+ /* The symbol can be locally resolved. */
+ rela.r_info = ELF32_R_INFO (0, R_390_IRELATIVE);
+ rela.r_addend = resolver_address;
+ }
+ else
+ {
+ rela.r_info = ELF32_R_INFO (h->dynindx, R_390_JMP_SLOT);
+ rela.r_addend = 0;
+ }
+
+ loc = relplt->contents + iplt_index * RELA_ENTRY_SIZE;
+ bfd_elf32_swap_reloca_out (output_bfd, &rela, loc);
+}
+
/* Finish up dynamic symbol handling. We set the contents of various
dynamic sections here. */
@@ -3029,6 +3453,7 @@ elf_s390_finish_dynamic_symbol (bfd *output_bfd,
Elf_Internal_Sym *sym)
{
struct elf_s390_link_hash_table *htab;
+ struct elf_s390_link_hash_entry *eh = (struct elf_s390_link_hash_entry*)h;
htab = elf_s390_hash_table (info);
@@ -3042,125 +3467,139 @@ elf_s390_finish_dynamic_symbol (bfd *output_bfd,
/* This symbol has an entry in the procedure linkage table. Set
it up. */
- if (h->dynindx == -1
- || htab->elf.splt == NULL
- || htab->elf.sgotplt == NULL
- || htab->elf.srelplt == NULL)
- abort ();
-
- /* Calc. index no.
- Current offset - size first entry / entry size. */
- plt_index = (h->plt.offset - PLT_FIRST_ENTRY_SIZE) / PLT_ENTRY_SIZE;
-
- /* Offset in GOT is PLT index plus GOT headers(3) times 4,
- addr & GOT addr. */
- got_offset = (plt_index + 3) * GOT_ENTRY_SIZE;
-
- /* S390 uses halfwords for relative branch calc! */
- relative_offset = - ((PLT_FIRST_ENTRY_SIZE +
- (PLT_ENTRY_SIZE * plt_index) + 18) / 2);
- /* If offset is > 32768, branch to a previous branch
- 390 can only handle +-64 K jumps. */
- if ( -32768 > (int) relative_offset )
- relative_offset
- = -(unsigned) (((65536 / PLT_ENTRY_SIZE - 1) * PLT_ENTRY_SIZE) / 2);
-
- /* Fill in the entry in the procedure linkage table. */
- if (!info->shared)
+ if (s390_is_ifunc_symbol_p (h))
{
- memcpy (htab->elf.splt->contents + h->plt.offset, elf_s390_plt_entry,
- PLT_ENTRY_SIZE);
-
- /* Adjust jump to the first plt entry. */
- bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
- htab->elf.splt->contents + h->plt.offset + 20);
-
- /* Push the GOT offset field. */
- bfd_put_32 (output_bfd,
- (htab->elf.sgotplt->output_section->vma
- + htab->elf.sgotplt->output_offset
- + got_offset),
- htab->elf.splt->contents + h->plt.offset + 24);
- }
- else if (got_offset < 4096)
- {
- /* The GOT offset is small enough to be used directly as
- displacement. */
- memcpy (htab->elf.splt->contents + h->plt.offset,
- elf_s390_plt_pic12_entry,
- PLT_ENTRY_SIZE);
-
- /* Put in the GOT offset as displacement value. The 0xc000
- value comes from the first word of the plt entry. Look
- at the elf_s390_plt_pic16_entry content. */
- bfd_put_16 (output_bfd, (bfd_vma)0xc000 | got_offset,
- htab->elf.splt->contents + h->plt.offset + 2);
-
- /* Adjust the jump to the first plt entry. */
- bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
- htab->elf.splt->contents + h->plt.offset + 20);
- }
- else if (got_offset < 32768)
- {
- /* The GOT offset is too big for a displacement but small
- enough to be a signed 16 bit immediate value as it can be
- used in an lhi instruction. */
- memcpy (htab->elf.splt->contents + h->plt.offset,
- elf_s390_plt_pic16_entry,
- PLT_ENTRY_SIZE);
-
- /* Put in the GOT offset for the lhi instruction. */
- bfd_put_16 (output_bfd, (bfd_vma)got_offset,
- htab->elf.splt->contents + h->plt.offset + 2);
-
- /* Adjust the jump to the first plt entry. */
- bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
- htab->elf.splt->contents + h->plt.offset + 20);
+ /* If we can resolve the IFUNC symbol locally we generate an
+ IRELATIVE reloc. */
+ elf_s390_finish_ifunc_symbol (output_bfd, info, h, htab, h->plt.offset,
+ eh->ifunc_resolver_address +
+ eh->ifunc_resolver_section->output_offset +
+ eh->ifunc_resolver_section->output_section->vma);
+ /* Fallthrough. Handling of explicit GOT slots of IFUNC
+ symbols is below. */
}
else
{
- memcpy (htab->elf.splt->contents + h->plt.offset,
- elf_s390_plt_pic_entry,
- PLT_ENTRY_SIZE);
+ if (h->dynindx == -1
+ || htab->elf.splt == NULL
+ || htab->elf.sgotplt == NULL
+ || htab->elf.srelplt == NULL)
+ abort ();
- /* Adjust the jump to the first plt entry. */
- bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
- htab->elf.splt->contents + h->plt.offset + 20);
+ /* Calc. index no.
+ Current offset - size first entry / entry size. */
+ plt_index = (h->plt.offset - PLT_FIRST_ENTRY_SIZE) / PLT_ENTRY_SIZE;
- /* Push the GOT offset field. */
- bfd_put_32 (output_bfd, got_offset,
- htab->elf.splt->contents + h->plt.offset + 24);
- }
- /* Insert offset into reloc. table here. */
- bfd_put_32 (output_bfd, plt_index * sizeof (Elf32_External_Rela),
- htab->elf.splt->contents + h->plt.offset + 28);
+ /* Offset in GOT is PLT index plus GOT headers(3) times 4,
+ addr & GOT addr. */
+ got_offset = (plt_index + 3) * GOT_ENTRY_SIZE;
- /* Fill in the entry in the global offset table.
- Points to instruction after GOT offset. */
- bfd_put_32 (output_bfd,
- (htab->elf.splt->output_section->vma
- + htab->elf.splt->output_offset
- + h->plt.offset
- + 12),
- htab->elf.sgotplt->contents + got_offset);
-
- /* Fill in the entry in the .rela.plt section. */
- rela.r_offset = (htab->elf.sgotplt->output_section->vma
- + htab->elf.sgotplt->output_offset
- + got_offset);
- rela.r_info = ELF32_R_INFO (h->dynindx, R_390_JMP_SLOT);
- rela.r_addend = 0;
- loc = htab->elf.srelplt->contents + plt_index * sizeof (Elf32_External_Rela);
- bfd_elf32_swap_reloca_out (output_bfd, &rela, loc);
+ /* S390 uses halfwords for relative branch calc! */
+ relative_offset = - ((PLT_FIRST_ENTRY_SIZE +
+ (PLT_ENTRY_SIZE * plt_index) + 18) / 2);
+ /* If offset is > 32768, branch to a previous branch
+ 390 can only handle +-64 K jumps. */
+ if ( -32768 > (int) relative_offset )
+ relative_offset
+ = -(unsigned) (((65536 / PLT_ENTRY_SIZE - 1) * PLT_ENTRY_SIZE) / 2);
- if (!h->def_regular)
- {
- /* Mark the symbol as undefined, rather than as defined in
- the .plt section. Leave the value alone. This is a clue
- for the dynamic linker, to make function pointer
- comparisons work between an application and shared
- library. */
- sym->st_shndx = SHN_UNDEF;
+ /* Fill in the entry in the procedure linkage table. */
+ if (!info->shared)
+ {
+ memcpy (htab->elf.splt->contents + h->plt.offset, elf_s390_plt_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Adjust jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ htab->elf.splt->contents + h->plt.offset + 20);
+
+ /* Push the GOT offset field. */
+ bfd_put_32 (output_bfd,
+ (htab->elf.sgotplt->output_section->vma
+ + htab->elf.sgotplt->output_offset
+ + got_offset),
+ htab->elf.splt->contents + h->plt.offset + 24);
+ }
+ else if (got_offset < 4096)
+ {
+ /* The GOT offset is small enough to be used directly as
+ displacement. */
+ memcpy (htab->elf.splt->contents + h->plt.offset,
+ elf_s390_plt_pic12_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Put in the GOT offset as displacement value. The 0xc000
+ value comes from the first word of the plt entry. Look
+ at the elf_s390_plt_pic16_entry content. */
+ bfd_put_16 (output_bfd, (bfd_vma)0xc000 | got_offset,
+ htab->elf.splt->contents + h->plt.offset + 2);
+
+ /* Adjust the jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ htab->elf.splt->contents + h->plt.offset + 20);
+ }
+ else if (got_offset < 32768)
+ {
+ /* The GOT offset is too big for a displacement but small
+ enough to be a signed 16 bit immediate value as it can be
+ used in an lhi instruction. */
+ memcpy (htab->elf.splt->contents + h->plt.offset,
+ elf_s390_plt_pic16_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Put in the GOT offset for the lhi instruction. */
+ bfd_put_16 (output_bfd, (bfd_vma)got_offset,
+ htab->elf.splt->contents + h->plt.offset + 2);
+
+ /* Adjust the jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ htab->elf.splt->contents + h->plt.offset + 20);
+ }
+ else
+ {
+ memcpy (htab->elf.splt->contents + h->plt.offset,
+ elf_s390_plt_pic_entry,
+ PLT_ENTRY_SIZE);
+
+ /* Adjust the jump to the first plt entry. */
+ bfd_put_32 (output_bfd, (bfd_vma) 0+(relative_offset << 16),
+ htab->elf.splt->contents + h->plt.offset + 20);
+
+ /* Push the GOT offset field. */
+ bfd_put_32 (output_bfd, got_offset,
+ htab->elf.splt->contents + h->plt.offset + 24);
+ }
+ /* Insert offset into reloc. table here. */
+ bfd_put_32 (output_bfd, plt_index * sizeof (Elf32_External_Rela),
+ htab->elf.splt->contents + h->plt.offset + 28);
+
+ /* Fill in the entry in the global offset table.
+ Points to instruction after GOT offset. */
+ bfd_put_32 (output_bfd,
+ (htab->elf.splt->output_section->vma
+ + htab->elf.splt->output_offset
+ + h->plt.offset
+ + 12),
+ htab->elf.sgotplt->contents + got_offset);
+
+ /* Fill in the entry in the .rela.plt section. */
+ rela.r_offset = (htab->elf.sgotplt->output_section->vma
+ + htab->elf.sgotplt->output_offset
+ + got_offset);
+ rela.r_info = ELF32_R_INFO (h->dynindx, R_390_JMP_SLOT);
+ rela.r_addend = 0;
+ loc = htab->elf.srelplt->contents + plt_index * sizeof (Elf32_External_Rela);
+ bfd_elf32_swap_reloca_out (output_bfd, &rela, loc);
+
+ if (!h->def_regular)
+ {
+ /* Mark the symbol as undefined, rather than as defined in
+ the .plt section. Leave the value alone. This is a clue
+ for the dynamic linker, to make function pointer
+ comparisons work between an application and shared
+ library. */
+ sym->st_shndx = SHN_UNDEF;
+ }
}
}
@@ -3187,9 +3626,37 @@ elf_s390_finish_dynamic_symbol (bfd *output_bfd,
of a version file, we just want to emit a RELATIVE reloc.
The entry in the global offset table will already have been
initialized in the relocate_section function. */
- if (info->shared
+ if (h->def_regular && s390_is_ifunc_symbol_p (h))
+ {
+ if (info->shared)
+ {
+ /* An explicit GOT slot usage needs GLOB_DAT. If the
+ symbol references local the implicit got.iplt slot
+ will be used and the IRELATIVE reloc has been created
+ above. */
+ goto do_glob_dat;
+ }
+ else
+ {
+ /* For non-shared objects explicit GOT slots must be
+ filled with the PLT slot address for pointer
+ equality reasons. */
+ bfd_put_32 (output_bfd, (htab->elf.iplt->output_section->vma
+ + htab->elf.iplt->output_offset
+ + h->plt.offset),
+ htab->elf.sgot->contents + h->got.offset);
+ return TRUE;
+ }
+ }
+ else if (info->shared
&& SYMBOL_REFERENCES_LOCAL (info, h))
{
+ /* If this is a static link, or it is a -Bsymbolic link and
+ the symbol is defined locally or was forced to be local
+ because of a version file, we just want to emit a
+ RELATIVE reloc. The entry in the global offset table
+ will already have been initialized in the
+ relocate_section function. */
if (!h->def_regular)
return FALSE;
BFD_ASSERT((h->got.offset & 1) != 0);
@@ -3201,6 +3668,7 @@ elf_s390_finish_dynamic_symbol (bfd *output_bfd,
else
{
BFD_ASSERT((h->got.offset & 1) == 0);
+ do_glob_dat:
bfd_put_32 (output_bfd, (bfd_vma) 0, htab->elf.sgot->contents + h->got.offset);
rela.r_info = ELF32_R_INFO (h->dynindx, R_390_GLOB_DAT);
rela.r_addend = 0;
@@ -3271,6 +3739,8 @@ elf_s390_finish_dynamic_sections (bfd *output_bfd,
struct elf_s390_link_hash_table *htab;
bfd *dynobj;
asection *sdyn;
+ bfd *ibfd;
+ unsigned int i;
htab = elf_s390_hash_table (info);
dynobj = htab->elf.dynobj;
@@ -3356,6 +3826,36 @@ elf_s390_finish_dynamic_sections (bfd *output_bfd,
elf_section_data (htab->elf.sgotplt->output_section)
->this_hdr.sh_entsize = 4;
}
+ /* Finish dynamic symbol for local IFUNC symbols. */
+ for (ibfd = info->input_bfds; ibfd != NULL; ibfd = ibfd->link_next)
+ {
+ struct plt_entry *local_plt;
+ Elf_Internal_Sym *isym;
+ Elf_Internal_Shdr *symtab_hdr;
+
+ symtab_hdr = &elf_symtab_hdr (ibfd);
+
+ local_plt = elf_s390_local_plt (ibfd);
+ if (local_plt != NULL)
+ for (i = 0; i < symtab_hdr->sh_info; i++)
+ {
+ if (local_plt[i].plt.offset != (bfd_vma) -1)
+ {
+ asection *sec = local_plt[i].sec;
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache, ibfd, i);
+ if (isym == NULL)
+ return FALSE;
+
+ if (ELF_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
+ elf_s390_finish_ifunc_symbol (output_bfd, info, NULL, htab,
+ local_plt[i].plt.offset,
+ isym->st_value
+ + sec->output_section->vma
+ + sec->output_offset);
+
+ }
+ }
+ }
return TRUE;
}
@@ -3446,6 +3946,7 @@ elf32_s390_merge_private_bfd_data (bfd *ibfd, bfd *obfd)
#define elf_backend_reloc_type_class elf_s390_reloc_type_class
#define elf_backend_grok_prstatus elf_s390_grok_prstatus
#define elf_backend_plt_sym_val elf_s390_plt_sym_val
+#define elf_backend_add_symbol_hook elf_s390_add_symbol_hook
#define bfd_elf32_mkobject elf_s390_mkobject
#define elf_backend_object_p elf_s390_object_p