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| author | H.J. Lu <hjl.tools@gmail.com> | 2021-05-26 12:13:13 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2021-05-26 12:13:24 -0700 |
| commit | 50c95a739c91ae70cf8481936611aa1f5397a384 (patch) | |
| tree | f539432154713f55c321e9dbd16251eb4f51eec7 /bfd/elfxx-x86.h | |
| parent | 11bb5c41eb98d8e7d4d75dfcf620f6f627523e77 (diff) | |
| download | gdb-50c95a739c91ae70cf8481936611aa1f5397a384.zip gdb-50c95a739c91ae70cf8481936611aa1f5397a384.tar.gz gdb-50c95a739c91ae70cf8481936611aa1f5397a384.tar.bz2 | |
x86: Propery check PC16 reloc overflow in 16-bit mode instructions
commit a7664973b24a242cd9ea17deb5eaf503065fc0bd
Author: Jan Beulich <jbeulich@suse.com>
Date: Mon Apr 26 10:41:35 2021 +0200
x86: correct overflow checking for 16-bit PC-relative relocs
caused linker failure when building 16-bit program in a 32-bit ELF
container. Update GNU_PROPERTY_X86_FEATURE_2_USED with
#define GNU_PROPERTY_X86_FEATURE_2_CODE16 (1U << 12)
to indicate that 16-bit mode instructions are used in the input object:
https://groups.google.com/g/x86-64-abi/c/UvvXWeHIGMA
to indicate that 16-bit mode instructions are used in the object to
allow linker to properly perform relocation overflow check for 16-bit
PC-relative relocations in 16-bit mode instructions.
1. Update x86 assembler to always generate the GNU property note with
GNU_PROPERTY_X86_FEATURE_2_CODE16 for .code16 in ELF object.
2. Update i386 and x86-64 linkers to use 16-bit PC16 relocations if
input object is marked with GNU_PROPERTY_X86_FEATURE_2_CODE16.
bfd/
PR ld/27905
* elf32-i386.c: Include "libiberty.h".
(elf_howto_table): Add 16-bit R_386_PC16 entry.
(elf_i386_rtype_to_howto): Add a BFD argument. Use 16-bit
R_386_PC16 if input has 16-bit mode instructions.
(elf_i386_info_to_howto_rel): Update elf_i386_rtype_to_howto
call.
(elf_i386_tls_transition): Likewise.
(elf_i386_relocate_section): Likewise.
* elf64-x86-64.c (x86_64_elf_howto_table): Add 16-bit
R_X86_64_PC16 entry.
(elf_x86_64_rtype_to_howto): Use 16-bit R_X86_64_PC16 if input
has 16-bit mode instructions.
* elfxx-x86.c (_bfd_x86_elf_parse_gnu_properties): Set
elf_x86_has_code16 if relocatable input is marked with
GNU_PROPERTY_X86_FEATURE_2_CODE16.
* elfxx-x86.h (elf_x86_obj_tdata): Add has_code16.
(elf_x86_has_code16): New.
binutils/
PR ld/27905
* readelf.c (decode_x86_feature_2): Support
GNU_PROPERTY_X86_FEATURE_2_CODE16.
gas/
PR ld/27905
* config/tc-i386.c (set_code_flag): Update x86_feature_2_used
with GNU_PROPERTY_X86_FEATURE_2_CODE16 for .code16 in ELF
object.
(set_16bit_gcc_code_flag): Likewise.
(x86_cleanup): Always generate the GNU property note if
x86_feature_2_used isn't 0.
* testsuite/gas/i386/code16-2.d: New file.
* testsuite/gas/i386/code16-2.s: Likewise.
* testsuite/gas/i386/x86-64-code16-2.d: Likewise.
* testsuite/gas/i386/i386.exp: Run code16-2 and x86-64-code16-2.
include/
PR ld/27905
* elf/common.h (GNU_PROPERTY_X86_FEATURE_2_CODE16): New.
ld/
PR ld/27905
* testsuite/ld-i386/code16.d: New file.
* testsuite/ld-i386/code16.t: Likewise.
* testsuite/ld-x86-64/code16.d: Likewise.
* testsuite/ld-x86-64/code16.t: Likewise.
* testsuite/ld-i386/i386.exp: Run code16.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
Diffstat (limited to 'bfd/elfxx-x86.h')
| -rw-r--r-- | bfd/elfxx-x86.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h index db11327..e834430 100644 --- a/bfd/elfxx-x86.h +++ b/bfd/elfxx-x86.h @@ -549,6 +549,9 @@ struct elf_x86_obj_tdata /* GOTPLT entries for TLS descriptors. */ bfd_vma *local_tlsdesc_gotent; + + /* Set if the objec file has 16-bit code. */ + unsigned int has_code16 : 1; }; enum elf_x86_plt_type @@ -584,6 +587,9 @@ struct elf_x86_plt #define elf_x86_local_tlsdesc_gotent(abfd) \ (elf_x86_tdata (abfd)->local_tlsdesc_gotent) +#define elf_x86_has_code16(abfd) \ + (elf_x86_tdata (abfd)->has_code16) + #define elf_x86_compute_jump_table_size(htab) \ ((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size) |