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Subject[tip:x86/asm] x86-64: Slightly shorten copy_page()
Commit-ID:  426932909093e4e7729777a0e2beed4b54911361
Gitweb: http://git.kernel.org/tip/426932909093e4e7729777a0e2beed4b54911361
Author: Jan Beulich <JBeulich@suse.com>
AuthorDate: Thu, 5 Jan 2012 16:12:25 +0000
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 6 Jan 2012 12:25:37 +0100

x86-64: Slightly shorten copy_page()

%r13 got saved and restored without ever getting touched, so
there's no need to do so.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F05D9F9020000780006AA0D@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/lib/copy_page_64.S | 12 ++++--------
1 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/x86/lib/copy_page_64.S b/arch/x86/lib/copy_page_64.S
index 01c805b..6b34d04 100644
--- a/arch/x86/lib/copy_page_64.S
+++ b/arch/x86/lib/copy_page_64.S
@@ -20,14 +20,12 @@ ENDPROC(copy_page_c)

ENTRY(copy_page)
CFI_STARTPROC
- subq $3*8,%rsp
- CFI_ADJUST_CFA_OFFSET 3*8
+ subq $2*8,%rsp
+ CFI_ADJUST_CFA_OFFSET 2*8
movq %rbx,(%rsp)
CFI_REL_OFFSET rbx, 0
movq %r12,1*8(%rsp)
CFI_REL_OFFSET r12, 1*8
- movq %r13,2*8(%rsp)
- CFI_REL_OFFSET r13, 2*8

movl $(4096/64)-5,%ecx
.p2align 4
@@ -91,10 +89,8 @@ ENTRY(copy_page)
CFI_RESTORE rbx
movq 1*8(%rsp),%r12
CFI_RESTORE r12
- movq 2*8(%rsp),%r13
- CFI_RESTORE r13
- addq $3*8,%rsp
- CFI_ADJUST_CFA_OFFSET -3*8
+ addq $2*8,%rsp
+ CFI_ADJUST_CFA_OFFSET -2*8
ret
.Lcopy_page_end:
CFI_ENDPROC

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