Messages in this thread Patch in this message | | | Date | Sat, 12 Jun 2021 06:42:47 -0000 | From | "tip-bot2 for Peter Zijlstra" <> | Subject | [tip: objtool/urgent] objtool: Only rewrite unconditional retpoline thunk calls |
| |
The following commit has been merged into the objtool/urgent branch of tip:
Commit-ID: 2d49b721dc18c113d5221f4cf5a6104eb66cb7f2 Gitweb: https://git.kernel.org/tip/2d49b721dc18c113d5221f4cf5a6104eb66cb7f2 Author: Peter Zijlstra <peterz@infradead.org> AuthorDate: Thu, 10 Jun 2021 09:04:29 +02:00 Committer: Peter Zijlstra <peterz@infradead.org> CommitterDate: Fri, 11 Jun 2021 08:53:06 +02:00
objtool: Only rewrite unconditional retpoline thunk calls
It turns out that the compilers generate conditional branches to the retpoline thunks like:
5d5: 0f 85 00 00 00 00 jne 5db <cpuidle_reflect+0x22> 5d7: R_X86_64_PLT32 __x86_indirect_thunk_r11-0x4
while the rewrite can only handle JMP/CALL to the thunks. The result is the alternative wrecking the code. Make sure to skip writing the alternatives for conditional branches.
Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls") Reported-by: Lukasz Majczak <lma@semihalf.com> Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Nathan Chancellor <nathan@kernel.org> --- tools/objtool/arch/x86/decode.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 24295d3..523aa41 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -747,6 +747,10 @@ int arch_rewrite_retpolines(struct objtool_file *file) list_for_each_entry(insn, &file->retpoline_call_list, call_node) { + if (insn->type != INSN_JUMP_DYNAMIC && + insn->type != INSN_CALL_DYNAMIC) + continue; + if (!strcmp(insn->sec->name, ".text.__x86.indirect_thunk")) continue;
| |