x86: make /proc/stat account for all interrupts

LAPIC interrupts, which don't go through the generic interrupt handling
code, aren't accounted for in /proc/stat. Hence this patch adds a
mechanism architectures can use to accordingly adjust the statistics.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 74a323d..903e617 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -472,6 +472,13 @@
 };
 #endif
 
+#ifndef arch_irq_stat_cpu
+#define arch_irq_stat_cpu(cpu) 0
+#endif
+#ifndef arch_irq_stat
+#define arch_irq_stat() 0
+#endif
+
 static int show_stat(struct seq_file *p, void *v)
 {
 	int i;
@@ -509,7 +516,9 @@
 			sum += temp;
 			per_irq_sum[j] += temp;
 		}
+		sum += arch_irq_stat_cpu(i);
 	}
+	sum += arch_irq_stat();
 
 	seq_printf(p, "cpu  %llu %llu %llu %llu %llu %llu %llu %llu %llu\n",
 		(unsigned long long)cputime64_to_clock_t(user),