x86/paravirt: Replace the paravirt nop with a bona fide empty function

[pandora-kernel.git] / arch / x86 / kernel / entry_64.S

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 8d15c69..f6daf3c 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1504,7 +1504,18 @@ END(error_exit)
        /* runs on exception stack */
 ENTRY(nmi)
        INTR_FRAME
+       /*
+        * Fix up the exception frame if we're on Xen.
+        * PARAVIRT_ADJUST_EXCEPTION_FRAME is guaranteed to push at most
+        * one value to the stack on native, so it may clobber the rdx
+        * scratch slot, but it won't clobber any of the important
+        * slots past it.
+        *
+        * Xen is a different story, because the Xen frame itself overlaps
+        * the "NMI executing" variable.
+        */
        PARAVIRT_ADJUST_EXCEPTION_FRAME
+
        pushq_cfi $-1
        subq $ORIG_RAX-R15, %rsp
        CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15