This is a note to let you know that I've just added the patch titled
x86/cpu: Fix __x86_return_thunk symbol type
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-cpu-fix-__x86_return_thunk-symbol-type.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 77f67119004296a9b2503b377d610e08b08afc2a Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Mon, 14 Aug 2023 13:44:27 +0200
Subject: x86/cpu: Fix __x86_return_thunk symbol type
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 77f67119004296a9b2503b377d610e08b08afc2a upstream.
Commit
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>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230814121148.571027074@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-6.4/x86-cpu-fix-up-srso_safe_ret-and-__x86_return_thunk.patch
queue-6.4/x86-static_call-fix-__static_call_fixup.patch
queue-6.4/x86-cpu-cleanup-the-untrain-mess.patch
queue-6.4/iopoll-call-cpu_relax-in-busy-loops.patch
queue-6.4/objtool-x86-fixup-frame-pointer-vs-rethunk.patch
queue-6.4/x86-retpoline-kprobes-skip-optprobe-check-for-indirect-jumps-with-retpolines-and-ibt.patch
queue-6.4/x86-retpoline-kprobes-fix-position-of-thunk-sections-with-config_lto_clang.patch
queue-6.4/x86-cpu-kvm-provide-untrain_ret_vm.patch
queue-6.4/x86-cpu-rename-srso_-.-_alias-to-srso_alias_-1.patch
queue-6.4/x86-alternative-make-custom-return-thunk-unconditional.patch
queue-6.4/x86-cpu-rename-original-retbleed-methods.patch
queue-6.4/objtool-x86-fix-srso-mess.patch
queue-6.4/x86-cpu-clean-up-srso-return-thunk-mess.patch
queue-6.4/x86-cpu-fix-__x86_return_thunk-symbol-type.patch
