x86/nmi/64: Minor asm simplification

Replace LEA; MOV with an equivalent SUB.  This saves one
instruction.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index d8ab2b2..0fb5252 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1420,8 +1420,7 @@ nested_nmi:
         * Modify the "iret" frame to point to repeat_nmi, forcing another
         * iteration of NMI handling.
         */
-       leaq    -1*8(%rsp), %rdx
-       movq    %rdx, %rsp
+       subq    $8, %rsp
        leaq    -10*8(%rsp), %rdx
        pushq   $__KERNEL_DS
        pushq   %rdx