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Message-ID: <20230816185839.GA3843691@dev-arch.thelio-3990X>
Date: Wed, 16 Aug 2023 11:58:39 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>,
Borislav Petkov <bp@...en8.de>
Cc: linux-tip-commits@...r.kernel.org, linux-kernel@...r.kernel.org,
x86@...nel.org
Subject: Re: [tip: x86/urgent] x86/cpu: Clean up SRSO return thunk mess
On Wed, Aug 16, 2023 at 07:55:16AM -0000, tip-bot2 for Peter Zijlstra wrote:
> The following commit has been merged into the x86/urgent branch of tip:
>
> Commit-ID: 9010e01a8efffa0d14972b79fbe87bd329d79bfd
> Gitweb: https://git.kernel.org/tip/9010e01a8efffa0d14972b79fbe87bd329d79bfd
> Author: Peter Zijlstra <peterz@...radead.org>
> AuthorDate: Mon, 14 Aug 2023 13:44:31 +02:00
> Committer: Borislav Petkov (AMD) <bp@...en8.de>
> CommitterDate: Wed, 16 Aug 2023 09:39:16 +02:00
>
> x86/cpu: Clean up SRSO return thunk mess
<snip>
> diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
> index a478eb5..fb81895 100644
> --- a/arch/x86/lib/retpoline.S
> +++ b/arch/x86/lib/retpoline.S
> @@ -151,22 +151,27 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
> .section .text..__x86.rethunk_untrain
>
> SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
> + UNWIND_HINT_FUNC
> ANNOTATE_NOENDBR
> ASM_NOP2
> lfence
> - jmp __x86_return_thunk
> + jmp srso_alias_return_thunk
> SYM_FUNC_END(srso_untrain_ret_alias)
> __EXPORT_THUNK(srso_untrain_ret_alias)
>
> .section .text..__x86.rethunk_safe
> +#else
> +/* dummy definition for alternatives */
> +SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
> + ANNOTATE_UNRET_SAFE
> + ret
> + int3
> +SYM_FUNC_END(srso_alias_untrain_ret)
Just a heads up, this series will have a small bisectability issue
because of this hunk, it needs
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index fb818957955b..7df8582fb64e 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -166,7 +166,7 @@ SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
ANNOTATE_UNRET_SAFE
ret
int3
-SYM_FUNC_END(srso_alias_untrain_ret)
+SYM_FUNC_END(srso_untrain_ret_alias)
#endif
SYM_START(srso_safe_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
but it obviously gets fixed by commit a3fd3ac0a605 ("x86/cpu: Rename
srso_(.*)_alias to srso_alias_\1") so it is probably fine. I only
noticed it because I cherry-picked the first five changes to my patched
-next tree.
Cheers,
Nathan
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