[PATCH v2 01/11] x86/cpu: Fixup __x86_return_thunk

From: Peter Zijlstra
Date: Mon Aug 14 2023 - 08:21:31 EST


Patch fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow
mitigation") reimplemented __x86_return_thunk with a mix of
SYM_FUNC_START and SYM_CODE_END, this is not a sane combination.

Since nothing should ever actually 'CALL' this, make it consistently
CODE.

Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/lib/retpoline.S | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -264,7 +264,9 @@ SYM_CODE_END(srso_safe_ret)
SYM_FUNC_END(srso_untrain_ret)
__EXPORT_THUNK(srso_untrain_ret)

-SYM_FUNC_START(__x86_return_thunk)
+SYM_CODE_START(__x86_return_thunk)
+ UNWIND_HINT_FUNC
+ ANNOTATE_NOENDBR
ALTERNATIVE_2 "jmp __ret", "call srso_safe_ret", X86_FEATURE_SRSO, \
"call srso_safe_ret_alias", X86_FEATURE_SRSO_ALIAS
int3