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-rw-r--r--arch/x86/kernel/alternative.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 6b8c93989..69f85e274 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -536,6 +536,7 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
}
#ifdef CONFIG_RETHUNK
+
/*
* Rewrite the compiler generated return thunk tail-calls.
*
@@ -551,14 +552,18 @@ static int patch_return(void *addr, struct insn *insn, u8 *bytes)
{
int i = 0;
- if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
- return -1;
+ if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) {
+ if (x86_return_thunk == __x86_return_thunk)
+ return -1;
- bytes[i++] = RET_INSN_OPCODE;
+ i = JMP32_INSN_SIZE;
+ __text_gen_insn(bytes, JMP32_INSN_OPCODE, addr, x86_return_thunk, i);
+ } else {
+ bytes[i++] = RET_INSN_OPCODE;
+ }
for (; i < insn->length;)
bytes[i++] = INT3_INSN_OPCODE;
-
return i;
}