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@xxxxxxxxxxxxx>
AuthorDate: Thu, 10 Jun 2021 09:04:29 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
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;
|