diff options
| -rw-r--r-- | arch/x86/kernel/alternative.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index b78d55f0dfad..3bb0a5f61e8c 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -693,13 +693,12 @@ static int patch_return(void *addr, struct insn *insn, u8 *bytes) { int i = 0; + /* Patch the custom return thunks... */ if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) { - if (x86_return_thunk == __x86_return_thunk) - return -1; - i = JMP32_INSN_SIZE; __text_gen_insn(bytes, JMP32_INSN_OPCODE, addr, x86_return_thunk, i); } else { + /* ... or patch them out if not needed. */ bytes[i++] = RET_INSN_OPCODE; } @@ -712,6 +711,14 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) { s32 *s; + /* + * Do not patch out the default return thunks if those needed are the + * ones generated by the compiler. + */ + if (cpu_feature_enabled(X86_FEATURE_RETHUNK) && + (x86_return_thunk == __x86_return_thunk)) + return; + for (s = start; s < end; s++) { void *dest = NULL, *addr = (void *)s + *s; struct insn insn; |