powerpc/time: account broadcast timer event interrupts separately

These are not local timer interrupts but IPIs. It's good to be able
to see how timer offloading is behaving, so split these out into
their own category.

Signed-off-by: Nicholas Piggin <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/include/asm/hardirq.h

···
 typedef struct {
 	unsigned int __softirq_pending;
 	unsigned int timer_irqs_event;
+	unsigned int broadcast_irqs_event;
 	unsigned int timer_irqs_others;
 	unsigned int pmu_irqs;
 	unsigned int mce_exceptions;

arch/powerpc/kernel/irq.c

···
 		seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs_event);
         seq_printf(p, "  Local timer interrupts for timer event device\n");
 
+	seq_printf(p, "%*s: ", prec, "BCT");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", per_cpu(irq_stat, j).broadcast_irqs_event);
+	seq_printf(p, "  Broadcast timer interrupts for timer event device\n");
+
 	seq_printf(p, "%*s: ", prec, "LOC");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs_others);
···
 {
 	u64 sum = per_cpu(irq_stat, cpu).timer_irqs_event;
 
+	sum += per_cpu(irq_stat, cpu).broadcast_irqs_event;
 	sum += per_cpu(irq_stat, cpu).pmu_irqs;
 	sum += per_cpu(irq_stat, cpu).mce_exceptions;
 	sum += per_cpu(irq_stat, cpu).spurious_irqs;

arch/powerpc/kernel/time.c

···
 void timer_broadcast_interrupt(void)
 {
 	u64 *next_tb = this_cpu_ptr(&decrementers_next_tb);
-	struct pt_regs *regs = get_irq_regs();
 
-	trace_timer_interrupt_entry(regs);
 	*next_tb = ~(u64)0;
 	tick_receive_broadcast();
-	__this_cpu_inc(irq_stat.timer_irqs_event);
-	trace_timer_interrupt_exit(regs);
+	__this_cpu_inc(irq_stat.broadcast_irqs_event);
 }
 #endif