arm64: smp: Fix missing IPI statistics

commit 83cfac9 ("genirq: Allow interrupts to be excluded from
/proc/interrupts") is to avoid IPIs appear twice in /proc/interrupts.
But the commit 331a1b3 ("arm64: smp: Add arch support for backtrace
using pseudo-NMI") and commit 2f5cd0c("arm64: kgdb: Implement
kgdb_roundup_cpus() to enable pseudo-NMI roundup") set CPU_BACKTRACE and
KGDB_ROUNDUP IPIs "IRQ_HIDDEN" flag but not show them in
arch_show_interrupts(), which cause the interrupt kstat_irqs accounting
is missing in display.

Before this patch, CPU_BACKTRACE and KGDB_ROUNDUP IPIs are missing:
	/ # cat /proc/interrupts
	           CPU0       CPU1       CPU2       CPU3
	 11:        466        600        309        332     GICv3  27 Level     arch_timer
	 13:         24          0          0          0     GICv3  33 Level     uart-pl011
	 15:         64          0          0          0     GICv3  78 Edge      virtio0
	 16:          0          0          0          0     GICv3  79 Edge      virtio1
	 17:          0          0          0          0     GICv3  34 Level     rtc-pl031
	 18:          3          3          3          3     GICv3  23 Level     arm-pmu
	 19:          0          0          0          0 9030000.pl061   3 Edge      GPIO Key Poweroff
	IPI0:         7         14          9         26       Rescheduling interrupts
	IPI1:       354         93        233        255       Function call interrupts
	IPI2:         0          0          0          0       CPU stop interrupts
	IPI3:         0          0          0          0       CPU stop (for crash dump) interrupts
	IPI4:         0          0          0          0       Timer broadcast interrupts
	IPI5:         1          0          0          0       IRQ work interrupts
	Err:          0

After this pacth, CPU_BACKTRACE and KGDB_ROUNDUP IPIs are displayed:
	/ # cat /proc/interrupts
	           CPU0       CPU1       CPU2       CPU3
	 11:        393        281        532        449     GICv3  27 Level     arch_timer
	 13:         15          0          0          0     GICv3  33 Level     uart-pl011
	 15:         64          0          0          0     GICv3  78 Edge      virtio0
	 16:          0          0          0          0     GICv3  79 Edge      virtio1
	 17:          0          0          0          0     GICv3  34 Level     rtc-pl031
	 18:          2          2          2          2     GICv3  23 Level     arm-pmu
	 19:          0          0          0          0 9030000.pl061   3 Edge      GPIO Key Poweroff
	IPI0:        11         19          4         23       Rescheduling interrupts
	IPI1:       279        347        222         72       Function call interrupts
	IPI2:         0          0          0          0       CPU stop interrupts
	IPI3:         0          0          0          0       CPU stop (for crash dump) interrupts
	IPI4:         0          0          0          0       Timer broadcast interrupts
	IPI5:         1          0          0          1       IRQ work interrupts
	IPI6:         0          0          0          0       CPU backtrace interrupts
	IPI7:         0          0          0          0       KGDB roundup interrupts
	Err:          0

Fixes: 331a1b3 ("arm64: smp: Add arch support for backtrace using pseudo-NMI")
Signed-off-by: Jinjie Ruan <[email protected]>
Suggested-by: Doug Anderson <[email protected]>
Acked-by: Will Deacon <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: Jinjie Ruan

arch/arm64/kernel/smp.c

@@ -762,13 +762,15 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-static const char *ipi_types[NR_IPI] __tracepoint_string = {
+static const char *ipi_types[MAX_IPI] __tracepoint_string = {
 	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
 	[IPI_CALL_FUNC]		= "Function call interrupts",
 	[IPI_CPU_STOP]		= "CPU stop interrupts",
 	[IPI_CPU_CRASH_STOP]	= "CPU stop (for crash dump) interrupts",
 	[IPI_TIMER]		= "Timer broadcast interrupts",
 	[IPI_IRQ_WORK]		= "IRQ work interrupts",
+	[IPI_CPU_BACKTRACE]	= "CPU backtrace interrupts",
+	[IPI_KGDB_ROUNDUP]	= "KGDB roundup interrupts",
 };
 
 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
@@ -779,7 +781,7 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 {
 	unsigned int cpu, i;
 
-	for (i = 0; i < NR_IPI; i++) {
+	for (i = 0; i < MAX_IPI; i++) {
 		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
 			   prec >= 4 ? " " : "");
 		for_each_online_cpu(cpu)