x86-64: Slightly shorten copy_page()
Jan Beulich [Thu, 5 Jan 2012 16:12:25 +0000 (16:12 +0000)]
%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

index 01c805b..6b34d04 100644 (file)
@@ -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