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| author | H.J. Lu <hjl.tools@gmail.com> | 2025-05-22 11:29:49 +0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2025-05-23 04:39:12 +0800 |
| commit | f9488b0d92b591bdf3ff8cce485cb0e1b3727cc0 (patch) | |
| tree | 1fd460bde882119705764c6dd10a3f37b23119d1 | |
| parent | 6558f9f5f0ccc107a083ae7fbf106ebcb5efa817 (diff) | |
| download | gdb-binutils-2_42-branch.zip gdb-binutils-2_42-branch.tar.gz gdb-binutils-2_42-branch.tar.bz2 | |
x86: Check MODRM for call and jmp in binutils older than 2.45binutils-2_42-branch
When i386 glibc was assembled with commit:
commit 11c2852449825a5f486f63bc40aabed56b7c04c1 (HEAD)
Author: Jan Beulich <jbeulich@suse.com>
Date: Fri Feb 21 10:24:50 2025 +0100
x86: widen @got{,pcrel} support to PUSH and APX IMUL
With us doing the transformation to an immediate operand for MOV and
various ALU insns, there's little reason to then not support the same
conversion for the other two insns which have respective immediate
operand forms. Unfortunately for IMUL (due to the 0F opcode prefix)
there's no suitable relocation, so the pre-APX forms cannot be marked
for relaxation in the assembler.
"pushl main@GOT(%ebx)" in sysdeps/i386/start.S was assembled to
1c: ff b3 00 00 00 00 push 0x0(%ebx) 1e: R_386_GOT32X main
Linkers in binutils versions older than 2.45 treated it as jmp and relaxed
it to
22c: e9 cf ff ff ff jmp 200 <main>
231: 90 nop
Update elf_i386_convert_load_reloc in binutils versions older than 2.45
to check MODRM for call and jmp to work with i386 glibc assembled with
binutils 2.45 or newer. Do the same in elf_x86_64_convert_load_reloc.
PR ld/32991
* elf32-i386.c (elf_i386_convert_load_reloc): Check MODRM for
call and jmp.
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Likewise.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 452f5511154ca02095a271cf085e17f536587207)
| -rw-r--r-- | bfd/elf32-i386.c | 9 | ||||
| -rw-r--r-- | bfd/elf64-x86-64.c | 9 |
2 files changed, 18 insertions, 0 deletions
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c index e2f88a1..f11500f 100644 --- a/bfd/elf32-i386.c +++ b/bfd/elf32-i386.c @@ -1335,6 +1335,15 @@ elf_i386_convert_load_reloc (bfd *abfd, Elf_Internal_Shdr *symtab_hdr, if (opcode == 0xff) { + switch (modrm & 0x38) + { + case 0x10: /* CALL */ + case 0x20: /* JMP */ + break; + default: + return true; + } + /* We have "call/jmp *foo@GOT[(%reg)]". */ if ((h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak) diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index 2ed120a..abf97b2 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -1851,6 +1851,15 @@ elf_x86_64_convert_load_reloc (bfd *abfd, /* Convert R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX to R_X86_64_PC32. */ modrm = bfd_get_8 (abfd, contents + roff - 1); + switch (modrm & 0x38) + { + case 0x10: /* CALL */ + case 0x20: /* JMP */ + break; + default: + return true; + } + if (modrm == 0x25) { /* Convert to "jmp foo nop". */ |