lkml.org 
[lkml]   [2013]   [Nov]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/asm] x86-64, copy_user: Use leal to produce 32-bit results
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

\
 
 \ /
  Last update: 2013-11-20 22:21    [W:0.091 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site