[PATCH] x86_64: Standardize i386/x86_64 handling of NMI_VECTOR

x86_64 and i386 behave inconsistently when sending an IPI on vector 2
(NMI_VECTOR).  Make both behave the same, so IPI 2 is sent as NMI.

The crash code was abusing send_IPI_allbutself() by passing a code
instead of a vector, it only worked because crash knew about the
internal code of send_IPI_allbutself().  Change crash to use NMI_VECTOR
instead, and remove the comment about how crash was abusing the function.

This patch is a pre-requisite for fixing the problem where sending an
IPI as NMI would reboot some Dell Xeon systems.  I cannot fix that
problem while crash continus to abuse send_IPI_allbutself().

It also removes the inconsistency between i386 and x86_64 for
NMI_VECTOR.  That will simplify all the RAS code that needs to bring
all the cpus to a clean stop, even when one or more cpus are spinning
disabled.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-i386/hw_irq.h b/include/asm-i386/hw_irq.h
index 95d3fd0..a4c0a5a 100644
--- a/include/asm-i386/hw_irq.h
+++ b/include/asm-i386/hw_irq.h
@@ -19,6 +19,8 @@
 
 struct hw_interrupt_type;
 
+#define NMI_VECTOR		0x02
+
 /*
  * Various low-level irq details needed by irq.c, process.c,
  * time.c, io_apic.c and smp.c