arm: ipi raise/start/end tracing

Add tracepoints for IPI raise events, and start and end of the
ipi handler.

Used to inspect the source of CPU wake-ups which are not already
traced - all other reasons for a CPU to wake-up are already
covered.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>

arch/arm/kernel/smp.c

@@ -46,6 +46,9 @@
 #include <asm/virt.h>
 #include <asm/mach/arch.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/arm-ipi.h>
+
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
@@ -604,6 +607,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 	if (ipinr < NR_IPI)
 		__inc_irq_stat(cpu, ipi_irqs[ipinr]);
 
+	trace_arm_ipi_entry(ipinr);
 	switch (ipinr) {
 	case IPI_WAKEUP:
 		break;
@@ -643,6 +647,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 		       cpu, ipinr);
 		break;
 	}
+	trace_arm_ipi_exit(ipinr);
 	set_irq_regs(old_regs);
 }
 

drivers/irqchip/irq-gic.c

@@ -41,6 +41,7 @@
 #include <linux/slab.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqchip/arm-gic.h>
+#include <trace/events/arm-ipi.h>
 
 #include <asm/irq.h>
 #include <asm/exception.h>
@@ -649,8 +650,10 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
 	unsigned long map = 0;
 
 	/* Convert our logical CPU mask into a physical one. */
-	for_each_cpu(cpu, mask)
+	for_each_cpu(cpu, mask) {
+		trace_arm_ipi_send(irq, cpu);
 		map |= gic_cpu_map[cpu];
+	}
 
 	/*
 	 * Ensure that stores to Normal memory are visible to the

include/trace/events/arm-ipi.h

@@ -0,0 +1,100 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM arm-ipi
+
+#if !defined(_TRACE_ARM_IPI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ARM_IPI_H
+
+#include <linux/tracepoint.h>
+
+#define show_arm_ipi_name(val)				\
+	__print_symbolic(val,				\
+			 { 0, "IPI_WAKEUP" },		\
+			 { 1, "IPI_TIMER" },		\
+			 { 2, "IPI_RESCHEDULE" },		\
+			 { 3, "IPI_CALL_FUNC" },		\
+			 { 4, "IPI_CALL_FUNC_SINGLE" },		\
+			 { 5, "IPI_CPU_STOP" },	\
+			 { 6, "IPI_COMPLETION" },		\
+			 { 7, "IPI_CPU_BACKTRACE" })
+
+DECLARE_EVENT_CLASS(arm_ipi,
+
+	TP_PROTO(unsigned int ipi_nr),
+
+	TP_ARGS(ipi_nr),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	ipi	)
+	),
+
+	TP_fast_assign(
+		__entry->ipi = ipi_nr;
+	),
+
+	TP_printk("ipi=%u [action=%s]", __entry->ipi,
+		show_arm_ipi_name(__entry->ipi))
+);
+
+/**
+ * arm_ipi_entry - called in the arm-generic ipi handler immediately before
+ *                 entering ipi-type handler
+ * @ipi_nr:  ipi number
+ *
+ * When used in combination with the arm_ipi_exit tracepoint
+ * we can determine the ipi handler runtine.
+ */
+DEFINE_EVENT(arm_ipi, arm_ipi_entry,
+
+	TP_PROTO(unsigned int ipi_nr),
+
+	TP_ARGS(ipi_nr)
+);
+
+/**
+ * arm_ipi_exit - called in the arm-generic ipi handler immediately
+ *                after the ipi-type handler returns
+ * @ipi_nr:  ipi number
+ *
+ * When used in combination with the arm_ipi_entry tracepoint
+ * we can determine the ipi handler runtine.
+ */
+DEFINE_EVENT(arm_ipi, arm_ipi_exit,
+
+	TP_PROTO(unsigned int ipi_nr),
+
+	TP_ARGS(ipi_nr)
+);
+
+/**
+ * arm_ipi_send - called as the ipi target mask is built, immediately
+ *                before the register is written
+ * @ipi_nr:  ipi number
+ * @dest:    cpu to send to
+ *
+ * When used in combination with the arm_ipi_entry tracepoint
+ * we can determine the ipi raise to run latency.
+ */
+TRACE_EVENT(arm_ipi_send,
+
+	TP_PROTO(unsigned int ipi_nr, int dest),
+
+	TP_ARGS(ipi_nr, dest),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	ipi	)
+		__field(	int			,	dest )
+	),
+
+	TP_fast_assign(
+		__entry->ipi = ipi_nr;
+		__entry->dest = dest;
+	),
+
+	TP_printk("dest=%d ipi=%u [action=%s]", __entry->dest,
+			__entry->ipi, show_arm_ipi_name(__entry->ipi))
+);
+
+#endif /*  _TRACE_ARM_IPI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>