The Inter Processor Interrupt is used on ARM to tell another processor to do
a specific action. This is mainly used to emulate a timer interrupt on an idle
cpu, force a cpu to reschedule or run a function on another processor context.
Add a tracepoint when raising an IPI and in the entry/exit handler functions.
When a cpu raises an IPI, the targeted cpus is an interesting information, the
cpumask conversion in hexa is added in the trace using the cpumask_scnprintf
function.
Tested-on Vexpress TC2 (5 processors).
Tested-on u8500 (2 processors).
Signed-off-by: Daniel Lezcano <daniel.lezc...@linaro.org>
---
arch/arm/include/asm/smp.h | 9 ++++
arch/arm/kernel/smp.c | 34 +++++++------
arch/arm64/include/asm/smp.h | 7 +++
arch/arm64/kernel/smp.c | 21 ++++++--
include/trace/events/ipi.h | 112 ++++++++++++++++++++++++++++++++++++++++++
5 files changed, 164 insertions(+), 19 deletions(-)
create mode 100644 include/trace/events/ipi.h
diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h
index a8cae71c..788706c 100644
--- a/arch/arm/include/asm/smp.h
+++ b/arch/arm/include/asm/smp.h
@@ -18,6 +18,15 @@
# error "<asm/smp.h> included in non-SMP build"
#endif
+enum ipi_msg_type {
+ IPI_WAKEUP,
+ IPI_TIMER,
+ IPI_RESCHEDULE,
+ IPI_CALL_FUNC,
+ IPI_CALL_FUNC_SINGLE,
+ IPI_CPU_STOP,
+};
+
#define raw_smp_processor_id() (current_thread_info()->cpu)
struct seq_file;
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 72024ea..9ca8ce8 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -46,6 +46,9 @@
#include <asm/mach/arch.h>
#include <asm/mpu.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/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
@@ -59,15 +62,6 @@ struct secondary_data secondary_data;
*/
volatile int pen_release = -1;
-enum ipi_msg_type {
- IPI_WAKEUP,
- IPI_TIMER,
- IPI_RESCHEDULE,
- IPI_CALL_FUNC,
- IPI_CALL_FUNC_SINGLE,
- IPI_CPU_STOP,
-};
-
static DECLARE_COMPLETION(cpu_running);
static struct smp_operations smp_ops;
@@ -433,19 +427,25 @@ void __init set_smp_cross_call(void (*fn)(const struct
cpumask *, unsigned int))
smp_cross_call = fn;
}
+static void ipi_raise(const struct cpumask *mask, int ipinr)
+{
+ trace_ipi_raise(mask, ipinr);
+ smp_cross_call(mask, ipinr);
+}
+
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
- smp_cross_call(mask, IPI_CALL_FUNC);
+ ipi_raise(mask, IPI_CALL_FUNC);
}
void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
{
- smp_cross_call(mask, IPI_WAKEUP);
+ ipi_raise(mask, IPI_WAKEUP);
}
void arch_send_call_function_single_ipi(int cpu)
{
- smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+ ipi_raise(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
}
static const char *ipi_types[NR_IPI] = {
@@ -487,7 +487,7 @@ u64 smp_irq_stat_cpu(unsigned int cpu)
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
void tick_broadcast(const struct cpumask *mask)
{
- smp_cross_call(mask, IPI_TIMER);
+ ipi_raise(mask, IPI_TIMER);
}
#endif
@@ -528,6 +528,8 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
unsigned int cpu = smp_processor_id();
struct pt_regs *old_regs = set_irq_regs(regs);
+ trace_ipi_handler_entry(ipinr);
+
if (ipinr < NR_IPI)
__inc_irq_stat(cpu, ipi_irqs[ipinr]);
@@ -571,11 +573,13 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
break;
}
set_irq_regs(old_regs);
+
+ trace_ipi_handler_exit(ipinr);
}
void smp_send_reschedule(int cpu)
{
- smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
+ ipi_raise(cpumask_of(cpu), IPI_RESCHEDULE);
}
void smp_send_stop(void)
@@ -586,7 +590,7 @@ void smp_send_stop(void)
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
if (!cpumask_empty(&mask))
- smp_cross_call(&mask, IPI_CPU_STOP);
+ ipi_raise(&mask, IPI_CPU_STOP);
/* Wait up to one second for other CPUs to stop */
timeout = USEC_PER_SEC;
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index 4b8023c..7ebaa3a 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -24,6 +24,13 @@
# error "<asm/smp.h> included in non-SMP build"
#endif
+enum ipi_msg_type {
+ IPI_RESCHEDULE,
+ IPI_CALL_FUNC,
+ IPI_CALL_FUNC_SINGLE,
+ IPI_CPU_STOP,
+};
+
#define raw_smp_processor_id() (current_thread_info()->cpu)
struct seq_file;
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 78db90d..c987b9f 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -48,6 +48,9 @@
#include <asm/tlbflush.h>
#include <asm/ptrace.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/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
@@ -426,14 +429,20 @@ void __init set_smp_cross_call(void (*fn)(const struct
cpumask *, unsigned int))
smp_cross_call = fn;
}
+static void ipi_raise(const struct cpumask *mask, int ipinr)
+{
+ trace_ipi_raise(mask, ipinr);
+ smp_cross_call(mask, ipinr);
+}
+
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
- smp_cross_call(mask, IPI_CALL_FUNC);
+ ipi_raise(mask, IPI_CALL_FUNC);
}
void arch_send_call_function_single_ipi(int cpu)
{
- smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+ ipi_raise(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
}
static const char *ipi_types[NR_IPI] = {
@@ -501,6 +510,8 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
unsigned int cpu = smp_processor_id();
struct pt_regs *old_regs = set_irq_regs(regs);
+ trace_ipi_handler_entry(ipinr);
+
if (ipinr >= IPI_RESCHEDULE && ipinr < IPI_RESCHEDULE + NR_IPI)
__inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_RESCHEDULE]);
@@ -532,11 +543,13 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
break;
}
set_irq_regs(old_regs);
+
+ trace_ipi_handler_exit(ipinr);
}
void smp_send_reschedule(int cpu)
{
- smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
+ ipi_raise(cpumask_of(cpu), IPI_RESCHEDULE);
}
void smp_send_stop(void)
@@ -549,7 +562,7 @@ void smp_send_stop(void)
cpumask_copy(&mask, cpu_online_mask);
cpu_clear(smp_processor_id(), mask);
- smp_cross_call(&mask, IPI_CPU_STOP);
+ ipi_raise(&mask, IPI_CPU_STOP);
}
/* Wait up to one second for other CPUs to stop */
diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
new file mode 100644
index 0000000..fa22d4f
--- /dev/null
+++ b/include/trace/events/ipi.h
@@ -0,0 +1,112 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ipi
+
+#if !defined(_TRACE_IPI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_IPI_H
+
+#include <linux/tracepoint.h>
+
+#define ipi_name(ipinr) { IPI_##ipinr, #ipinr }
+#define show_ipi_name(val) \
+ __print_symbolic(val, \
+ ipi_name(WAKEUP), \
+ ipi_name(TIMER), \
+ ipi_name(RESCHEDULE), \
+ ipi_name(CALL_FUNC), \
+ ipi_name(CALL_FUNC_SINGLE), \
+ ipi_name(CPU_STOP))
+
+#define show_cpumask(srcp) \
+ ({ \
+ char *buf = __get_dynamic_array(buf); \
+ cpumask_scnprintf(buf, NR_CPUS, srcp); \
+ buf; \
+ })
+
+DECLARE_EVENT_CLASS(ipi,
+
+ TP_PROTO(int ipinr),
+
+ TP_ARGS(ipinr),
+
+ TP_STRUCT__entry(
+ __field(int, ipinr)
+ ),
+
+ TP_fast_assign(
+ __entry->ipinr = ipinr;
+ ),
+
+ TP_printk("ipi=%d, name=%s", __entry->ipinr,
+ show_ipi_name(__entry->ipinr))
+);
+
+/**
+ * ipi_handle_entry - called right before the IPI handler
+ * @ipinr: the IPI number
+ *
+ * The @ipinr value must be valid and the action name associated with
+ * the IPI value is given in the trace.
+ */
+DEFINE_EVENT_CONDITION(ipi, ipi_handler_entry,
+
+ TP_PROTO(int ipinr),
+
+ TP_ARGS(ipinr),
+
+ TP_CONDITION(ipinr < NR_IPI && ipinr >= 0)
+);
+
+/**
+ * ipi_handle_exit - called right after the IPI handler
+ * @ipinr: the IPI number
+ *
+ * The @ipinr value must be valid and the action name associated with
+ * the IPI value is given in the trace.
+ */
+DEFINE_EVENT_CONDITION(ipi, ipi_handler_exit,
+
+ TP_PROTO(int ipinr),
+
+ TP_ARGS(ipinr),
+
+ TP_CONDITION(ipinr < NR_IPI && ipinr >= 0)
+);
+
+/**
+ * ipi_raise - called when a smp cross call is made
+ * @ipinr: the IPI number
+ * @cpumask: the recipients for the IPI
+ *
+ * The @ipinr value must be valid and the action name associated with
+ * the IPI value is given in the trace as well as the cpumask of the
+ * targeted cpus.
+ */
+TRACE_EVENT_CONDITION(ipi_raise,
+
+ TP_PROTO(const struct cpumask *cpumask, int ipinr),
+
+ TP_ARGS(cpumask, ipinr),
+
+ TP_CONDITION(ipinr < NR_IPI && ipinr >= 0),
+
+ TP_STRUCT__entry(
+ __field(int, ipinr)
+ __field(const struct cpumask *, cpumask)
+ __dynamic_array(char, buf, NR_CPUS)
+ ),
+
+ TP_fast_assign(
+ __entry->ipinr = ipinr;
+ __entry->cpumask = cpumask;
+ ),
+
+ TP_printk("ipi=%d, cpumask=0x%s, name=%s", __entry->ipinr,
+ show_cpumask(__entry->cpumask),
+ show_ipi_name(__entry->ipinr))
+);
+
+#endif /* _TRACE_IPI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
1.7.9.5
--
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