x86/entry/64: Use POP instead of MOV to restore regs on NMI return

This gets rid of the last user of the old RESTORE_..._REGS infrastructure.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/652a260f17a160789bc6a41d997f98249b73e2ab.1509609304.git.luto@kernel.org
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 b5a0ea6..5b2f0bc 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1559,11 +1559,14 @@ end_repeat_nmi:
 nmi_swapgs:
        SWAPGS_UNSAFE_STACK
 nmi_restore:
-       RESTORE_EXTRA_REGS
-       RESTORE_C_REGS
+       POP_EXTRA_REGS
+       POP_C_REGS
 
-       /* Point RSP at the "iret" frame. */
-       REMOVE_PT_GPREGS_FROM_STACK 6*8
+       /*
+        * Skip orig_ax and the "outermost" frame to point RSP at the "iret"
+        * at the "iret" frame.
+        */
+       addq    $6*8, %rsp
 
        /*
         * Clear "NMI executing".  Set DF first so that we can easily