@@ -1441,7 +1441,18 @@ 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
+
/*
* We allow breakpoints in NMIs. If a breakpoint occurs, then
* the iretq it performs will take us out of NMI context.
@@ -41,10 +41,18 @@
#include <asm/timer.h>
#include <asm/special_insns.h>
-/* nop stub */
-void _paravirt_nop(void)
-{
-}
+/*
+ * nop stub, which must not clobber anything *including the stack* to
+ * avoid confusing the entry prologues.
+ */
+extern void _paravirt_nop(void);
+asm (".pushsection .entry.text, \"ax\"\n"
+ ".global _paravirt_nop\n"
+ "_paravirt_nop:\n\t"
+ "ret\n\t"
+ ".size _paravirt_nop, . - _paravirt_nop\n\t"
+ ".type _paravirt_nop, @function\n\t"
+ ".popsection");
/* identity function, which can be inlined */
u32 _paravirt_ident_32(u32 x)