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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.

Make the leal explicit, both to be more obvious and since that is what
gcc generates and thus is less likely to trigger obscure gas bugs.

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>
This commit is contained in:
H. Peter Anvin 2013-11-20 12:50:51 -08:00
parent f4cb1cc18f
commit 661c80192d
1 changed files with 2 additions and 2 deletions
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4
arch/x86/lib/copy_user_64.S
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@ -186,7 +186,7 @@ ENTRY(copy_user_generic_unrolled)
30: shll $6,%ecx 30: shll $6,%ecx
addl %ecx,%edx addl %ecx,%edx
jmp 60f jmp 60f
40: lea (%rdx,%rcx,8),%rdx 40: leal (%rdx,%rcx,8),%edx
jmp 60f jmp 60f
50: movl %ecx,%edx 50: movl %ecx,%edx
60: jmp copy_user_handle_tail /* ecx is zerorest also */ 60: jmp copy_user_handle_tail /* ecx is zerorest also */
@ -252,7 +252,7 @@ ENTRY(copy_user_generic_string)
ret ret
.section .fixup,"ax" .section .fixup,"ax"
11: lea (%rdx,%rcx,8),%rcx 11: leal (%rdx,%rcx,8),%ecx
12: movl %ecx,%edx /* ecx is zerorest also */ 12: movl %ecx,%edx /* ecx is zerorest also */
jmp copy_user_handle_tail jmp copy_user_handle_tail
.previous .previous