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| author | Alan Modra <amodra@gmail.com> | 2014-01-13 13:51:16 +1030 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2014-01-13 15:04:15 +1030 |
| commit | c7e17e05b647f6233c2062d038e5421686217816 (patch) | |
| tree | 5a76b6781f9f40342b24ddd40ffa5b1e781a7ff6 | |
| parent | 1a4416c4c7f02a73652429f4e8e8e966f55e3e8b (diff) | |
| download | gdb-c7e17e05b647f6233c2062d038e5421686217816.zip gdb-c7e17e05b647f6233c2062d038e5421686217816.tar.gz gdb-c7e17e05b647f6233c2062d038e5421686217816.tar.bz2 | |
Error on shared lib call to @local ifunc
On powerpc32, making ifuncs have non-default visibility in shared
libraries or pies can result in runtime failures. The problem is that
if gcc is told that a given function has non-default visibility, then
calls to that function are assumed to be local (which is true) and
thus need not go via a plt call stub (which is false for ifunc). If
the caller has no other reason to set up the got pointer (r30), code
won't be emitted to do so. However, a pic plt call stub makes use of
r30 to load the plt entry. So a call to an ifunc, which always needs
a plt entry, will fail.
This patch makes ld emit an error for the problem case, and allows
calls to non-default visibility ifuncs to work in normal executables.
I also fix some cases where ifuncs fail when using the old bss-plt.
* elf32-ppc.c (ppc_elf_check_relocs): For @local call to ifunc,
error when shared and force a plt call otherwise.
(ppc_elf_size_dynamic_sections): Don't emit DT_PPC_GOT unless
plt_type == PLT_NEW.
(ppc_elf_relocate_section): Add missing test to resolve ifuncs to
the appropriate call stub.
| -rw-r--r-- | bfd/elf32-ppc.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c index b601f05..61c45d8 100644 --- a/bfd/elf32-ppc.c +++ b/bfd/elf32-ppc.c @@ -4283,6 +4283,20 @@ ppc_elf_check_relocs (bfd *abfd, htab->plt_type = PLT_OLD; htab->old_bfd = abfd; } + if (h != NULL && h->type == STT_GNU_IFUNC) + { + if (info->shared) + { + info->callbacks->einfo (_("%P: %H: @local call to ifunc %s\n"), + abfd, sec, rel->r_offset, + h->root.root.string); + bfd_set_error (bfd_error_bad_value); + return FALSE; + } + h->needs_plt = 1; + if (!update_plt_info (abfd, &h->plt.plist, NULL, 0)) + return FALSE; + } break; /* This relocation describes the C++ object vtable hierarchy. @@ -6481,7 +6495,9 @@ ppc_elf_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED, return FALSE; } - if (htab->glink != NULL && htab->glink->size != 0) + if (htab->plt_type == PLT_NEW + && htab->glink != NULL + && htab->glink->size != 0) { if (!add_dynamic_entry (DT_PPC_GOT, 0)) return FALSE; @@ -7863,7 +7879,8 @@ ppc_elf_relocate_section (bfd *output_bfd, unresolved_reloc = FALSE; if (htab->plt_type == PLT_NEW || !htab->elf.dynamic_sections_created - || h == NULL) + || h == NULL + || h->dynindx == -1) relocation = (htab->glink->output_section->vma + htab->glink->output_offset + (ent->glink_offset & ~1)); |