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| author | Andreas Krebbel <krebbel@linux.vnet.ibm.com> | 2018-09-17 11:01:24 +0200 |
|---|---|---|
| committer | Andreas Krebbel <krebbel@linux.ibm.com> | 2018-09-17 11:01:24 +0200 |
| commit | e6213e09ed0ef6ee40d00981c38baac6964aa95b (patch) | |
| tree | ca32212da5f51751ecf178dd17e5b271ed87224d /bfd/elf64-s390.c | |
| parent | cb5248409d7a5a10748c2aa70824ecddf2f913d5 (diff) | |
| download | gdb-e6213e09ed0ef6ee40d00981c38baac6964aa95b.zip gdb-e6213e09ed0ef6ee40d00981c38baac6964aa95b.tar.gz gdb-e6213e09ed0ef6ee40d00981c38baac6964aa95b.tar.bz2 | |
S/390: Prevent GOT access rewrite for certain symbols
When dereferencing a GOT slot with lgrl or lg we rewrite this using
larl to get rid of the extra memory access. However, we cannot do
this for:
- symbols marked for absolute addressing
- symbols at odd addresses (larl can handle only even addresses)
Fixed with the attached patch.
bfd/ChangeLog:
2018-09-17 Andreas Krebbel <krebbel@linux.ibm.com>
* elf64-s390.c (elf_s390_relocate_section): Prevent rewriting of
GOT accesses with larl for ABS or misaligned symbols.
ld/ChangeLog:
2018-09-17 Andreas Krebbel <krebbel@linux.ibm.com>
* testsuite/ld-s390/gotreloc-1.s: Add tests for ABS and misaligned
symbol. Move variables into data section. Make bar 8 bytes wide.
* testsuite/ld-s390/gotreloc-1.ver: Make misaligned_sym resolve locally.
* testsuite/ld-s390/gotreloc_31-1.dd: Adjust patterns.
* testsuite/ld-s390/gotreloc_64-norelro-1.dd: Likewise.
* testsuite/ld-s390/gotreloc_64-relro-1.dd: Likewise.
Diffstat (limited to 'bfd/elf64-s390.c')
| -rw-r--r-- | bfd/elf64-s390.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c index 91b76bc..c2a2955 100644 --- a/bfd/elf64-s390.c +++ b/bfd/elf64-s390.c @@ -2341,6 +2341,9 @@ elf_s390_relocate_section (bfd *output_bfd, && SYMBOL_REFERENCES_LOCAL (info, h)) || resolved_to_zero) { + Elf_Internal_Sym *isym; + asection *sym_sec; + /* This is actually a static link, or it is a -Bsymbolic link and the symbol is defined locally, or the symbol was forced to be local @@ -2362,6 +2365,10 @@ elf_s390_relocate_section (bfd *output_bfd, h->got.offset |= 1; } + /* When turning a GOT slot dereference into a direct + reference using larl we have to make sure that + the symbol is 1. properly aligned and 2. it is no + ABS symbol or will become one. */ if ((h->def_regular && bfd_link_pic (info) && SYMBOL_REFERENCES_LOCAL (info, h)) @@ -2376,8 +2383,17 @@ elf_s390_relocate_section (bfd *output_bfd, contents + rel->r_offset - 2) & 0xff00f000) == 0xe300c000 && bfd_get_8 (input_bfd, - contents + rel->r_offset + 3) == 0x04))) - + contents + rel->r_offset + 3) == 0x04)) + && (isym = bfd_sym_from_r_symndx (&htab->sym_cache, + input_bfd, r_symndx)) + && isym->st_shndx != SHN_ABS + && h != htab->elf.hdynamic + && h != htab->elf.hgot + && h != htab->elf.hplt + && !(isym->st_value & 1) + && (sym_sec = bfd_section_from_elf_index (input_bfd, + isym->st_shndx)) + && sym_sec->alignment_power) { unsigned short new_insn = (0xc000 | (bfd_get_8 (input_bfd, |