From e6213e09ed0ef6ee40d00981c38baac6964aa95b Mon Sep 17 00:00:00 2001 From: Andreas Krebbel Date: Mon, 17 Sep 2018 11:01:24 +0200 Subject: 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 * 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 * 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. --- bfd/elf64-s390.c | 20 ++++++++++++++++++-- ld/testsuite/ld-s390/gotreloc-1.s | 12 ++++++++++-- ld/testsuite/ld-s390/gotreloc-1.ver | 2 +- ld/testsuite/ld-s390/gotreloc_31-1.dd | 14 +++++++------- ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd | 14 +++++++------- ld/testsuite/ld-s390/gotreloc_64-relro-1.dd | 14 +++++++------- 6 files changed, 50 insertions(+), 26 deletions(-) diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c index 91b76bcc8a9..c2a2955b36b 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, diff --git a/ld/testsuite/ld-s390/gotreloc-1.s b/ld/testsuite/ld-s390/gotreloc-1.s index b60d6c13817..0e1f6f7715d 100644 --- a/ld/testsuite/ld-s390/gotreloc-1.s +++ b/ld/testsuite/ld-s390/gotreloc-1.s @@ -1,4 +1,4 @@ - .text +.text .globl foo foo: lgrl %r1,bar@GOTENT @@ -6,6 +6,14 @@ foo: lrl %r1,bar@GOTENT l %r1,bar@GOT(%r12) ly %r1,bar@GOT(%r12) + lgrl %r1,_GLOBAL_OFFSET_TABLE_@GOTENT + lgrl %r1,misaligned_sym@GOTENT +.data .globl bar -bar: .long 0x123 +bar: .quad 0x123 + +.globl misaligned_sym + .byte 1 +misaligned_sym: + .quad 42 diff --git a/ld/testsuite/ld-s390/gotreloc-1.ver b/ld/testsuite/ld-s390/gotreloc-1.ver index 1cb06d6986e..0eb6096d948 100644 --- a/ld/testsuite/ld-s390/gotreloc-1.ver +++ b/ld/testsuite/ld-s390/gotreloc-1.ver @@ -1 +1 @@ -{ local: bar; }; +{ local: bar; misaligned_sym; }; diff --git a/ld/testsuite/ld-s390/gotreloc_31-1.dd b/ld/testsuite/ld-s390/gotreloc_31-1.dd index 5e3f824353c..b1cf37c54d6 100644 --- a/ld/testsuite/ld-s390/gotreloc_31-1.dd +++ b/ld/testsuite/ld-s390/gotreloc_31-1.dd @@ -4,10 +4,10 @@ tmpdir/gotreloc_31-1: file format elf32-s390 Disassembly of section .text: .* : -.*: c4 18 00 00 08 4e [ ]*lgrl %r1,118c <_GLOBAL_OFFSET_TABLE_\+0xc> -.*: e3 10 c0 0c 00 04 [ ]*lg %r1,12\(%r12\) -.*: c0 10 00 00 00 08 [ ]*larl %r1,10c -.*: 58 10 c0 0c [ ]*l %r1,12\(%r12\) -.*: c0 10 00 00 00 03 [ ]*larl %r1,10c -.* : -.*: 00 00 01 23 .long 0x00000123 +.*: c4 18 00 00 08 56 [ ]*lgrl %r1,11b4 <_GLOBAL_OFFSET_TABLE_\+0x14> +.*: e3 10 c0 14 00 04 [ ]*lg %r1,20\(%r12\) +.*: c0 10 00 00 08 52 [ ]*larl %r1,11b8 +.*: 58 10 c0 14 [ ]*l %r1,20\(%r12\) +.*: c0 10 00 00 08 4d [ ]*larl %r1,11b8 +.*: c4 18 00 00 08 46 [ ]*lgrl %r1,11b0 <_GLOBAL_OFFSET_TABLE_\+0x10> +.*: c4 18 00 00 08 41 [ ]*lgrl %r1,11ac <_GLOBAL_OFFSET_TABLE_\+0xc> diff --git a/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd b/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd index 8c8c619edf5..8debd975d07 100644 --- a/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd +++ b/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd @@ -3,10 +3,10 @@ tmpdir/gotreloc_64-1: file format elf64-s390 Disassembly of section .text: .* : -.*: c0 10 00 00 00 0e [ ]*larl %r1,.* -.*: c0 10 00 00 00 0b [ ]*larl %r1,.* -.*: c4 1d 00 00 08 86 [ ]*lrl %r1,.* <_GLOBAL_OFFSET_TABLE_\+0x18> -.*: 58 10 c0 18 [ ]*l %r1,24\(%r12\) -.*: e3 10 c0 18 00 58 [ ]*ly %r1,24\(%r12\) -.* : -.*: 00 00 01 23 .long 0x00000123 +.*: c0 10 00 00 08 9c [ ]*larl %r1,12e8 +.*: c0 10 00 00 08 99 [ ]*larl %r1,12e8 +.*: c4 1d 00 00 08 92 [ ]*lrl %r1,12e0 <_GLOBAL_OFFSET_TABLE_\+0x28> +.*: 58 10 c0 28 [ ]*l %r1,40\(%r12\) +.*: e3 10 c0 28 00 58 [ ]*ly %r1,40\(%r12\) +.*: c4 18 00 00 08 86 [ ]*lgrl %r1,12d8 <_GLOBAL_OFFSET_TABLE_\+0x20> +.*: c4 18 00 00 08 7f [ ]*lgrl %r1,12d0 <_GLOBAL_OFFSET_TABLE_\+0x18> diff --git a/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd b/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd index 36f5001a78f..64151d10a7c 100644 --- a/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd +++ b/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd @@ -3,10 +3,10 @@ tmpdir/gotreloc_64-1: file format elf64-s390 Disassembly of section .text: .* : -.*: c0 10 00 00 00 0e [ ]*larl %r1,.* -.*: c0 10 00 00 00 0b [ ]*larl %r1,.* -.*: c4 1d 00 00 0f 1a [ ]*lrl %r1,.* <_GLOBAL_OFFSET_TABLE_\+0x18> -.*: 58 10 c0 18 [ ]*l %r1,24\(%r12\) -.*: e3 10 c0 18 00 58 [ ]*ly %r1,24\(%r12\) -.* : -.*: 00 00 01 23 .long 0x00000123 +.*: c0 10 00 00 0f 0c [ ]*larl %r1,2000 +.*: c0 10 00 00 0f 09 [ ]*larl %r1,2000 +.*: c4 1d 00 00 0f 02 [ ]*lrl %r1,1ff8 <_GLOBAL_OFFSET_TABLE_\+0x28> +.*: 58 10 c0 28 [ ]*l %r1,40\(%r12\) +.*: e3 10 c0 28 00 58 [ ]*ly %r1,40\(%r12\) +.*: c4 18 00 00 0e f6 [ ]*lgrl %r1,1ff0 <_GLOBAL_OFFSET_TABLE_\+0x20> +.*: c4 18 00 00 0e ef [ ]*lgrl %r1,1fe8 <_GLOBAL_OFFSET_TABLE_\+0x18> -- cgit v1.2.1