linux-kernel - [PATCH] x86/alternatives: Remove double patching in ALTERNATIVE

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Date:   Sat,  8 Oct 2022 16:14:29 -0400
From:   Brian Gerst <brgerst@...il.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Brian Gerst <brgerst@...il.com>
Subject: [PATCH] x86/alternatives: Remove double patching in ALTERNATIVE_TERNARY

Use ALT_NOT(feature) instead of X86_FEATURE_ALWAYS to avoid patching the
code twice when the feature is present.

Signed-off-by: Brian Gerst <brgerst@...il.com>
---
 arch/x86/include/asm/alternative.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 9542c582d546..f4efce972277 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -181,7 +181,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
-	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
+	ALTERNATIVE_2(oldinstr, newinstr_no, ALT_NOT(feature),		\
 		      newinstr_yes, feature)
 
 #define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \
@@ -386,7 +386,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
 #define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
-	ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
+	ALTERNATIVE_2 oldinstr, newinstr_no, ALT_NOT(feature),		\
 	newinstr_yes, feature
 
 #endif /* __ASSEMBLY__ */
-- 
2.37.3