x86, mce: add MCE poll count to /proc/interrupts

Keep a count of the machine check polls (or CMCI events) in
/proc/interrupts.

Andi needs this for debugging, but it's also useful in general
to see what's going in by the kernel.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/mce.h

@@ -125,6 +125,7 @@ static inline void mce_amd_feature_init(struct cpuinfo_x86 *c) { }
 int mce_available(struct cpuinfo_x86 *c);
 
 DECLARE_PER_CPU(unsigned, mce_exception_count);
+DECLARE_PER_CPU(unsigned, mce_poll_count);
 
 void mce_log_therm_throt_event(__u64 status);
 

arch/x86/kernel/cpu/mcheck/mce.c

@@ -264,6 +264,8 @@ static inline void mce_get_rip(struct mce *m, struct pt_regs *regs)
 	}
 }
 
+DEFINE_PER_CPU(unsigned, mce_poll_count);
+
 /*
  * Poll for corrected events or events that happened before reset.
  * Those are just logged through /dev/mcelog.
@@ -275,6 +277,8 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 	struct mce m;
 	int i;
 
+	__get_cpu_var(mce_poll_count)++;
+
 	mce_setup(&m);
 
 	m.mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);

arch/x86/kernel/irq.c

@@ -100,6 +100,10 @@ static int show_other_interrupts(struct seq_file *p, int prec)
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
 	seq_printf(p, "  Machine check exceptions\n");
+	seq_printf(p, "%*s: ", prec, "MCP");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
+	seq_printf(p, "  Machine check polls\n");
 #endif
 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
 #if defined(CONFIG_X86_IO_APIC)