linux-kernel - [tip: x86/core] x86/copy_user

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Date:   Mon, 13 Dec 2021 09:50:23 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Borislav Petkov <bp@...e.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/core] x86/copy_user_64: Remove .fixup usage

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     acba44d2436d463f60a54bf934d378dcf384a965
Gitweb:        https://git.kernel.org/tip/acba44d2436d463f60a54bf934d378dcf384a965
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Wed, 10 Nov 2021 11:01:05 +01:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Sat, 11 Dec 2021 09:09:45 +01:00

x86/copy_user_64: Remove .fixup usage

Place the anonymous .fixup code at the tail of the regular functions.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@...hat.com>
Reviewed-by: Borislav Petkov <bp@...e.de>
Link: https://lore.kernel.org/r/20211110101325.068505810@infradead.org
---
 arch/x86/lib/copy_user_64.S | 32 +++++++++++---------------------
 1 file changed, 11 insertions(+), 21 deletions(-)

diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 8fb562f..e6ac385 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -32,14 +32,10 @@
 	decl %ecx
 	jnz 100b
 102:
-	.section .fixup,"ax"
-103:	addl %ecx,%edx			/* ecx is zerorest also */
-	jmp .Lcopy_user_handle_tail
-	.previous
 
-	_ASM_EXTABLE_CPY(100b, 103b)
-	_ASM_EXTABLE_CPY(101b, 103b)
-	.endm
+	_ASM_EXTABLE_CPY(100b, .Lcopy_user_handle_align)
+	_ASM_EXTABLE_CPY(101b, .Lcopy_user_handle_align)
+.endm
 
 /*
  * copy_user_generic_unrolled - memory copy with exception handling.
@@ -107,7 +103,6 @@ SYM_FUNC_START(copy_user_generic_unrolled)
 	ASM_CLAC
 	RET
 
-	.section .fixup,"ax"
 30:	shll $6,%ecx
 	addl %ecx,%edx
 	jmp 60f
@@ -115,7 +110,6 @@ SYM_FUNC_START(copy_user_generic_unrolled)
 	jmp 60f
 50:	movl %ecx,%edx
 60:	jmp .Lcopy_user_handle_tail /* ecx is zerorest also */
-	.previous
 
 	_ASM_EXTABLE_CPY(1b, 30b)
 	_ASM_EXTABLE_CPY(2b, 30b)
@@ -166,20 +160,16 @@ SYM_FUNC_START(copy_user_generic_string)
 	movl %edx,%ecx
 	shrl $3,%ecx
 	andl $7,%edx
-1:	rep
-	movsq
+1:	rep movsq
 2:	movl %edx,%ecx
-3:	rep
-	movsb
+3:	rep movsb
 	xorl %eax,%eax
 	ASM_CLAC
 	RET
 
-	.section .fixup,"ax"
 11:	leal (%rdx,%rcx,8),%ecx
 12:	movl %ecx,%edx		/* ecx is zerorest also */
 	jmp .Lcopy_user_handle_tail
-	.previous
 
 	_ASM_EXTABLE_CPY(1b, 11b)
 	_ASM_EXTABLE_CPY(3b, 12b)
@@ -203,16 +193,13 @@ SYM_FUNC_START(copy_user_enhanced_fast_string)
 	cmpl $64,%edx
 	jb .L_copy_short_string	/* less then 64 bytes, avoid the costly 'rep' */
 	movl %edx,%ecx
-1:	rep
-	movsb
+1:	rep movsb
 	xorl %eax,%eax
 	ASM_CLAC
 	RET
 
-	.section .fixup,"ax"
 12:	movl %ecx,%edx		/* ecx is zerorest also */
 	jmp .Lcopy_user_handle_tail
-	.previous
 
 	_ASM_EXTABLE_CPY(1b, 12b)
 SYM_FUNC_END(copy_user_enhanced_fast_string)
@@ -240,6 +227,11 @@ SYM_CODE_START_LOCAL(.Lcopy_user_handle_tail)
 	RET
 
 	_ASM_EXTABLE_CPY(1b, 2b)
+
+.Lcopy_user_handle_align:
+	addl %ecx,%edx			/* ecx is zerorest also */
+	jmp .Lcopy_user_handle_tail
+
 SYM_CODE_END(.Lcopy_user_handle_tail)
 
 /*
@@ -350,7 +342,6 @@ SYM_FUNC_START(__copy_user_nocache)
 	sfence
 	RET
 
-	.section .fixup,"ax"
 .L_fixup_4x8b_copy:
 	shll $6,%ecx
 	addl %ecx,%edx
@@ -366,7 +357,6 @@ SYM_FUNC_START(__copy_user_nocache)
 .L_fixup_handle_tail:
 	sfence
 	jmp .Lcopy_user_handle_tail
-	.previous
 
 	_ASM_EXTABLE_CPY(1b, .L_fixup_4x8b_copy)
 	_ASM_EXTABLE_CPY(2b, .L_fixup_4x8b_copy)