This is a note to let you know that I've just added the patch titled
x86/srso: Improve i-cache locality for alias mitigation
to the 6.6-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-srso-improve-i-cache-locality-for-alias-mitigation.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0a784a06a7d1f06a74962616bf7222463a145b2b Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Date: Mon, 4 Sep 2023 22:04:55 -0700
Subject: x86/srso: Improve i-cache locality for alias mitigation
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Commit aa730cff0c26244e88066b5b461a9f5fbac13823 upstream.
Move srso_alias_return_thunk() to the same section as
srso_alias_safe_ret() so they can share a cache line.
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Acked-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/eadaf5530b46a7ae8b936522da45ae555d2b3393.1693889988.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/lib/retpoline.S | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -177,15 +177,14 @@ SYM_START(srso_alias_safe_ret, SYM_L_GLO
int3
SYM_FUNC_END(srso_alias_safe_ret)
- .section .text..__x86.return_thunk
-
-SYM_CODE_START(srso_alias_return_thunk)
+SYM_CODE_START_NOALIGN(srso_alias_return_thunk)
UNWIND_HINT_FUNC
ANNOTATE_NOENDBR
call srso_alias_safe_ret
ud2
SYM_CODE_END(srso_alias_return_thunk)
+ .section .text..__x86.return_thunk
/*
* Some generic notes on the untraining sequences:
*
Patches currently in stable-queue which might be from jpoimboe@xxxxxxxxxx are
queue-6.6/x86-srso-improve-i-cache-locality-for-alias-mitigation.patch
queue-6.6/x86-srso-disentangle-rethunk-dependent-options.patch
queue-6.6/x86-nospec-refactor-untrain_ret.patch
