x86, UV: Set DELIVERY_MODE=4 for vector=NMI_VECTOR in uv_hub_send_ipi()

When sending a NMI_VECTOR IPI using the UV_HUB_IPI_INT register,
we need to ensure the delivery mode field of that register has
NMI delivery selected.

This makes those IPIs true NMIs, instead of flat IPIs. It
matters to reboot sequences and KGDB, both of which use NMI
IPIs.
Signed-off-by: NRobin Holt <holt@sgi.com>
Acked-by: NJack Steiner <steiner@sgi.com>
Cc: Martin Hicks <mort@sgi.com>
Cc: <stable@kernel.org>
LKML-Reference: <20091020193620.877322000@alcatraz.americas.sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/include/asm/uv/uv_hub.h

@@ -19,6 +19,8 @@
 #include <asm/types.h>
 #include <asm/percpu.h>
 #include <asm/uv/uv_mmrs.h>
+#include <asm/irq_vectors.h>
+#include <asm/io_apic.h>
 
 
 /*
@@ -435,9 +437,14 @@ static inline void uv_set_cpu_scir_bits(int cpu, unsigned char value)
 static inline void uv_hub_send_ipi(int pnode, int apicid, int vector)
 {
 	unsigned long val;
+	unsigned long dmode = dest_Fixed;
+
+	if (vector == NMI_VECTOR)
+		dmode = dest_NMI;
 
 	val = (1UL << UVH_IPI_INT_SEND_SHFT) |
 			((apicid) << UVH_IPI_INT_APIC_ID_SHFT) |
+			(dmode << UVH_IPI_INT_DELIVERY_MODE_SHFT) |
 			(vector << UVH_IPI_INT_VECTOR_SHFT);
 	uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
 }