[PATCH 4/4] (RFC) X86: add IPI tracepoints

[Nicolas Pitre]

On X86 there are already tracepoints for IRQ vectors through which IPIs
are handled.  However this is highly X86 specific, and the IPI signaling
is not currently traced.

This is an attempt at adding generic IPI tracepoints to X86.

Signed-off-by: Nicolas Pitre <nico at linaro.org>
---
 arch/x86/kernel/smp.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index be8e1bde07..e154d176cf 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -31,6 +31,12 @@
 #include <asm/apic.h>
 #include <asm/nmi.h>
 #include <asm/trace/irq_vectors.h>
+
+#define CREATE_TRACE_POINTS
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#include <trace/events/ipi.h>
+
 /*
  *	Some notes on x86 processor bugs affecting SMP operation:
  *
@@ -124,11 +130,13 @@ static void native_smp_send_reschedule(int cpu)
 		WARN_ON(1);
 		return;
 	}
+	trace_ipi_raise(cpumask_of(cpu), tracepoint_string("RESCHEDULE"));
 	apic->send_IPI_mask(cpumask_of(cpu), RESCHEDULE_VECTOR);
 }
 
 void native_send_call_func_single_ipi(int cpu)
 {
+	trace_ipi_raise(cpumask_of(cpu), tracepoint_string("CALL_FUNCTION_SINGLE"));
 	apic->send_IPI_mask(cpumask_of(cpu), CALL_FUNCTION_SINGLE_VECTOR);
 }
 
@@ -136,6 +144,8 @@ void native_send_call_func_ipi(const struct cpumask *mask)
 {
 	cpumask_var_t allbutself;
 
+	trace_ipi_raise(mask, tracepoint_string("CALL_FUNCTION"));
+
 	if (!alloc_cpumask_var(&allbutself, GFP_ATOMIC)) {
 		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
 		return;
@@ -252,8 +262,10 @@ finish:
  */
 static inline void __smp_reschedule_interrupt(void)
 {
+	trace_ipi_entry(tracepoint_string("RESCHEDULE"));
 	inc_irq_stat(irq_resched_count);
 	scheduler_ipi();
+	trace_ipi_exit(tracepoint_string("RESCHEDULE"));
 }
 
 __visible void smp_reschedule_interrupt(struct pt_regs *regs)
@@ -291,8 +303,10 @@ __visible void smp_trace_reschedule_interrupt(struct pt_regs *regs)
 
 static inline void __smp_call_function_interrupt(void)
 {
+	trace_ipi_entry(tracepoint_string("CALL_FUNCTION"));
 	generic_smp_call_function_interrupt();
 	inc_irq_stat(irq_call_count);
+	trace_ipi_exit(tracepoint_string("CALL_FUNCTION"));
 }
 
 __visible void smp_call_function_interrupt(struct pt_regs *regs)
@@ -313,8 +327,10 @@ __visible void smp_trace_call_function_interrupt(struct pt_regs *regs)
 
 static inline void __smp_call_function_single_interrupt(void)
 {
+	trace_ipi_entry(tracepoint_string("CALL_FUNCTION_SINGLE"));
 	generic_smp_call_function_single_interrupt();
 	inc_irq_stat(irq_call_count);
+	trace_ipi_exit(tracepoint_string("CALL_FUNCTION_SINGLE"));
 }
 
 __visible void smp_call_function_single_interrupt(struct pt_regs *regs)
-- 
1.8.4.108.g55ea5f6