[PATCH] x86-64: slightly shorten copy_page()

From: Jan Beulich
Date: Thu Jan 05 2012 - 11:11:31 EST


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

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

---
arch/x86/lib/copy_page_64.S | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

--- 3.2/arch/x86/lib/copy_page_64.S
+++ 3.2-x86_64-copy_page/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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