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From: "tip-bot for H. Peter Anvin" <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org,
	torvalds@linux-foundation.org, fenghua.yu@intel.com,
	tglx@linutronix.de, hpa@linux.intel.com
Subject: [tip:x86/asm] x86-64, copy_user: Use leal to produce 32-bit results
Date: Wed, 20 Nov 2013 12:54:35 -0800	[thread overview]
Message-ID: <tip-372474e12a858807f03f73cb30e830a76fd1ae07@git.kernel.org> (raw)
In-Reply-To: <1384634221-6006-1-git-send-email-fenghua.yu@intel.com>

Commit-ID:  372474e12a858807f03f73cb30e830a76fd1ae07
Gitweb:     http://git.kernel.org/tip/372474e12a858807f03f73cb30e830a76fd1ae07
Author:     H. Peter Anvin <hpa@linux.intel.com>
AuthorDate: Wed, 20 Nov 2013 12:50:51 -0800
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Wed, 20 Nov 2013 12:50:51 -0800

x86-64, copy_user: Use leal to produce 32-bit results

When we are using lea to produce a 32-bit result, we can use the leal
form, rather than using leaq and worry about truncation elsewhere.

Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1384634221-6006-1-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/lib/copy_user_64.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index ffe4eb9..f00a87c 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -186,7 +186,7 @@ ENTRY(copy_user_generic_unrolled)
 30:	shll $6,%ecx
 	addl %ecx,%edx
 	jmp 60f
-40:	lea (%rdx,%rcx,8),%rdx
+40:	lea (%rdx,%rcx,8),%edx
 	jmp 60f
 50:	movl %ecx,%edx
 60:	jmp copy_user_handle_tail /* ecx is zerorest also */
@@ -252,7 +252,7 @@ ENTRY(copy_user_generic_string)
 	ret
 
 	.section .fixup,"ax"
-11:	lea (%rdx,%rcx,8),%rcx
+11:	lea (%rdx,%rcx,8),%ecx
 12:	movl %ecx,%edx		/* ecx is zerorest also */
 	jmp copy_user_handle_tail
 	.previous

  parent reply	other threads:[~2013-11-20 20:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-16 20:37 [PATCH] x86/copy_user.S: Remove zero byte check before copy user buffer Fenghua Yu
2013-11-17  6:18 ` [tip:x86/asm] x86-64, copy_user: " tip-bot for Fenghua Yu
     [not found]   ` <CA+55aFyFz_6oy8-1jb5Jzk+4VC5MLA5d0KbqhZxki0=+DmggBg@mail.gmail.com>
2013-11-17  6:51     ` H. Peter Anvin
2013-11-19  4:37     ` H. Peter Anvin
2013-11-19 19:38       ` Linus Torvalds
2013-11-20 19:12         ` H. Peter Anvin
2013-11-20 19:28     ` H. Peter Anvin
2013-11-20 20:13       ` Linus Torvalds
2013-11-20 20:36         ` H. Peter Anvin
2013-11-20 21:44           ` Linus Torvalds
2013-11-20 20:54 ` tip-bot for H. Peter Anvin [this message]
2013-11-20 22:00 ` [tip:x86/asm] x86-64, copy_user: Use leal to produce 32-bit results tip-bot for H. Peter Anvin

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