s390/irq: count cpu restart events

Count CPU Restart events and make them visible via /proc/interrupts.
Every CPU hotplug (online) event will increase the per cpu counter.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/irq.h

@@ -42,6 +42,7 @@ enum interruption_class {
 	IRQIO_PCI,
 	IRQIO_MSI,
 	NMI_NMI,
+	CPU_RST,
 	NR_ARCH_IRQS
 };
 

arch/s390/kernel/irq.c

@@ -82,6 +82,7 @@ static const struct irq_class irqclass_sub_desc[NR_ARCH_IRQS] = {
 	[IRQIO_PCI]  = {.name = "PCI", .desc = "[I/O] PCI Interrupt" },
 	[IRQIO_MSI]  = {.name = "MSI", .desc = "[I/O] MSI Interrupt" },
 	[NMI_NMI]    = {.name = "NMI", .desc = "[NMI] Machine Check"},
+	[CPU_RST]    = {.name = "RST", .desc = "[CPU] CPU Restart"},
 };
 
 /*

arch/s390/kernel/smp.c

@@ -709,6 +709,7 @@ static void __cpuinit smp_start_secondary(void *cpuvoid)
 	pfault_init();
 	notify_cpu_starting(smp_processor_id());
 	set_cpu_online(smp_processor_id(), true);
+	inc_irq_stat(CPU_RST);
 	local_irq_enable();
 	/* cpu_idle will call schedule for us */
 	cpu_idle();