linux-kernel - [PATCH 2/2] x86/ibt: Avoid duplicate ENDBR in __put_user

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Date:   Wed, 02 Aug 2023 12:55:47 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        jpoimboe@...nel.org, andrew.cooper3@...rix.com,
        David.Kaplan@....com
Subject: [PATCH 2/2] x86/ibt: Avoid duplicate ENDBR in __put_user_nocheck*()

Commit cb855971d717 ("x86/putuser: Provide room for padding") changed
__put_user_nocheck_*() into proper functions but failed to note that
SYM_FUNC_START() already provides ENDBR, rendering the explicit ENDBR
superfluous.

Fixes: cb855971d717 ("x86/putuser: Provide room for padding")
Reported-by: David Kaplan <David.Kaplan@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/lib/putuser.S |    4 ----
 1 file changed, 4 deletions(-)

--- a/arch/x86/lib/putuser.S
+++ b/arch/x86/lib/putuser.S
@@ -56,7 +56,6 @@ SYM_FUNC_END(__put_user_1)
 EXPORT_SYMBOL(__put_user_1)
 
 SYM_FUNC_START(__put_user_nocheck_1)
-	ENDBR
 	ASM_STAC
 2:	movb %al,(%_ASM_CX)
 	xor %ecx,%ecx
@@ -76,7 +75,6 @@ SYM_FUNC_END(__put_user_2)
 EXPORT_SYMBOL(__put_user_2)
 
 SYM_FUNC_START(__put_user_nocheck_2)
-	ENDBR
 	ASM_STAC
 4:	movw %ax,(%_ASM_CX)
 	xor %ecx,%ecx
@@ -96,7 +94,6 @@ SYM_FUNC_END(__put_user_4)
 EXPORT_SYMBOL(__put_user_4)
 
 SYM_FUNC_START(__put_user_nocheck_4)
-	ENDBR
 	ASM_STAC
 6:	movl %eax,(%_ASM_CX)
 	xor %ecx,%ecx
@@ -119,7 +116,6 @@ SYM_FUNC_END(__put_user_8)
 EXPORT_SYMBOL(__put_user_8)
 
 SYM_FUNC_START(__put_user_nocheck_8)
-	ENDBR
 	ASM_STAC
 9:	mov %_ASM_AX,(%_ASM_CX)
 #ifdef CONFIG_X86_32