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* elf64-ppc.c (struct ppc_stub_hash_entry): Delete "addend". (ppc64_elf_size_stubs): Don't set "addend". (ppc64_elf_relocate_section): Don't allow calls via toc-adjusting stubs without a following nop even in an executable, except for self-calls and both libc_start_main and .libc_start_main. gold/ * powerpc.cc (Target_powerpc::Relocate::relocate): Update self-call comment.
This commit is contained in:
Alan Modra
parent
c66bb0eea0
commit
ba8ca3e739
@ -1,3 +1,12 @@
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2013-07-03 Alan Modra <amodra@gmail.com>
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* elf64-ppc.c (struct ppc_stub_hash_entry): Delete "addend".
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(ppc64_elf_size_stubs): Don't set "addend".
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(ppc64_elf_relocate_section): Don't allow calls via
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toc-adjusting stubs without a following nop even in an
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executable, except for self-calls and both libc_start_main
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and .libc_start_main.
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2013-07-03 Alan Modra <amodra@gmail.com>
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* elf64-ppc.c (ppc64_elf_func_desc_adjust): Hide ".TOC.".
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115
bfd/elf64-ppc.c
115
bfd/elf64-ppc.c
@ -3618,9 +3618,6 @@ struct ppc_stub_hash_entry {
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struct ppc_link_hash_entry *h;
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struct plt_entry *plt_ent;
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/* And the reloc addend that this was derived from. */
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bfd_vma addend;
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/* Where this stub is being called from, or, in the case of combined
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stub sections, the first input section in the group. */
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asection *id_sec;
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@ -11752,7 +11749,6 @@ ppc64_elf_size_stubs (struct bfd_link_info *info, bfd_signed_vma group_size,
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}
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stub_entry->h = hash;
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stub_entry->plt_ent = plt_ent;
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stub_entry->addend = irela->r_addend;
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if (stub_entry->h != NULL)
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htab->stub_globals += 1;
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@ -13015,60 +13011,89 @@ ppc64_elf_relocate_section (bfd *output_bfd,
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{
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bfd_boolean can_plt_call = FALSE;
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/* All of these stubs will modify r2, so there must be a
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branch and link followed by a nop. The nop is
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replaced by an insn to restore r2. */
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if (rel->r_offset + 8 <= input_section->size)
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{
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unsigned long nop;
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nop = bfd_get_32 (input_bfd, contents + rel->r_offset + 4);
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if (nop == NOP
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|| nop == CROR_151515 || nop == CROR_313131)
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unsigned long br;
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br = bfd_get_32 (input_bfd,
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contents + rel->r_offset);
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if ((br & 1) != 0)
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{
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if (h != NULL
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&& (h == htab->tls_get_addr_fd
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|| h == htab->tls_get_addr)
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&& !htab->no_tls_get_addr_opt)
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unsigned long nop;
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nop = bfd_get_32 (input_bfd,
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contents + rel->r_offset + 4);
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if (nop == NOP
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|| nop == CROR_151515 || nop == CROR_313131)
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{
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/* Special stub used, leave nop alone. */
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if (h != NULL
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&& (h == htab->tls_get_addr_fd
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|| h == htab->tls_get_addr)
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&& !htab->no_tls_get_addr_opt)
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{
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/* Special stub used, leave nop alone. */
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}
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else
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bfd_put_32 (input_bfd, LD_R2_40R1,
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contents + rel->r_offset + 4);
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can_plt_call = TRUE;
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}
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else
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bfd_put_32 (input_bfd, LD_R2_40R1,
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contents + rel->r_offset + 4);
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}
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}
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if (!can_plt_call && h != NULL)
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{
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const char *name = h->elf.root.root.string;
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if (*name == '.')
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++name;
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if (strncmp (name, "__libc_start_main", 17) == 0
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&& (name[17] == 0 || name[17] == '@'))
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{
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/* Allow crt1 branch to go via a toc adjusting
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stub. Other calls that never return could do
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the same, if we could detect such. */
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can_plt_call = TRUE;
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}
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}
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if (!can_plt_call)
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{
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if (stub_entry->stub_type == ppc_stub_plt_call
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|| stub_entry->stub_type == ppc_stub_plt_call_r2save)
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{
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/* If this is a plain branch rather than a branch
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and link, don't require a nop. However, don't
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allow tail calls in a shared library as they
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will result in r2 being corrupted. */
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unsigned long br;
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br = bfd_get_32 (input_bfd, contents + rel->r_offset);
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if (info->executable && (br & 1) == 0)
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can_plt_call = TRUE;
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else
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stub_entry = NULL;
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}
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else if (h != NULL
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&& strcmp (h->elf.root.root.string,
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".__libc_start_main") == 0)
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{
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/* Allow crt1 branch to go via a toc adjusting stub. */
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can_plt_call = TRUE;
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}
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else
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{
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info->callbacks->einfo
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(_("%P: %H: call to `%T' lacks nop, can't restore toc; "
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"recompile with -fPIC"),
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input_bfd, input_section, rel->r_offset, sym_name);
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/* g++ as of 20130507 emits self-calls without a
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following nop. This is arguably wrong since we
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have conflicting information. On the one hand a
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global symbol and on the other a local call
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sequence, but don't error for this special case.
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It isn't possible to cheaply verify we have
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exactly such a call. Allow all calls to the same
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section. */
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asection *code_sec = sec;
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bfd_set_error (bfd_error_bad_value);
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ret = FALSE;
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if (get_opd_info (sec) != NULL)
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{
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bfd_vma off = (relocation + addend
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- sec->output_section->vma
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- sec->output_offset);
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opd_entry_value (sec, off, &code_sec, NULL, FALSE);
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}
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if (code_sec == input_section)
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can_plt_call = TRUE;
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}
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if (!can_plt_call)
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{
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info->callbacks->einfo
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(_("%P: %H: call to `%T' lacks nop, can't restore toc; "
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"recompile with -fPIC"),
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input_bfd, input_section, rel->r_offset, sym_name);
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bfd_set_error (bfd_error_bad_value);
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ret = FALSE;
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}
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if (can_plt_call
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@ -1,3 +1,8 @@
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2013-07-03 Alan Modra <amodra@gmail.com>
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* powerpc.cc (Target_powerpc::Relocate::relocate): Update self-call
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comment.
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2013-07-01 Cary Coutant <ccoutant@google.com>
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* dwarf_reader.cc (Dwarf_ranges_table::read_ranges_table): Save
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@ -6346,10 +6346,13 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
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}
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if (!can_plt_call)
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{
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// This is not an error in one special case: A self
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// call. It isn't possible to cheaply verify we have
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// such a call so just check for a call to the same
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// section.
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// g++ as of 20130507 emits self-calls without a
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// following nop. This is arguably wrong since we have
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// conflicting information. On the one hand a global
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// symbol and on the other a local call sequence, but
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// don't error for this special case.
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// It isn't possible to cheaply verify we have exactly
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// such a call. Allow all calls to the same section.
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bool ok = false;
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Address code = value;
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if (gsym->source() == Symbol::FROM_OBJECT
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