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Date:   Sat, 23 Sep 2023 12:20:10 -0000
From:   "tip-bot2 for Josh Poimboeuf" <tip-bot2@linutronix.de>
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Subject: [tip: x86/bugs] x86/srso: Improve i-cache locality for alias mitigation
Cc:     Josh Poimboeuf <jpoimboe@kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        "Borislav Petkov (AMD)" <bp@alien8.de>, x86@kernel.org,
        linux-kernel@vger.kernel.org
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The following commit has been merged into the x86/bugs branch of tip:

Commit-ID:     01c032b1b11620232f0405d477d33acb7870388c
Gitweb:        https://git.kernel.org/tip/01c032b1b11620232f0405d477d33acb7870388c
Author:        Josh Poimboeuf <jpoimboe@kernel.org>
AuthorDate:    Mon, 04 Sep 2023 22:04:55 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Sat, 23 Sep 2023 14:13:02 +02:00

x86/srso: Improve i-cache locality for alias mitigation

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@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/eadaf5530b46a7ae8b936522da45ae555d2b3393.1693889988.git.jpoimboe@kernel.org
---
 arch/x86/lib/retpoline.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index cd86aeb..9ab634f 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -177,15 +177,14 @@ SYM_START(srso_alias_safe_ret, SYM_L_GLOBAL, SYM_A_NONE)
 	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:
  *