perf: Provide generic perf_sample_data initialization

This makes it easier to extend perf_sample_data and fixes a bug on arm
and sparc, which failed to set ->raw to NULL, which can cause crashes
when combined with PERF_SAMPLE_RAW.

It also optimizes PowerPC and tracepoint, because the struct
initialization is forced to zero out the whole structure.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Jean Pihet <jpihet@mvista.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Jamie Iles <jamie.iles@picochip.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: stable@kernel.org
LKML-Reference: <20100304140100.315416040@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/arm/kernel/perf_event.c

@@ -965,7 +965,7 @@ armv6pmu_handle_irq(int irq_num,
 	 */
 	armv6_pmcr_write(pmcr);
 
-	data.addr = 0;
+	perf_sample_data_init(&data, 0);
 
 	cpuc = &__get_cpu_var(cpu_hw_events);
 	for (idx = 0; idx <= armpmu->num_events; ++idx) {
@@ -1945,7 +1945,7 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
 	 */
 	regs = get_irq_regs();
 
-	data.addr = 0;
+	perf_sample_data_init(&data, 0);
 
 	cpuc = &__get_cpu_var(cpu_hw_events);
 	for (idx = 0; idx <= armpmu->num_events; ++idx) {

arch/powerpc/kernel/perf_event.c

@@ -1164,10 +1164,10 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 	 * Finally record data if requested.
 	 */
 	if (record) {
-		struct perf_sample_data data = {
-			.addr	= ~0ULL,
-			.period	= event->hw.last_period,
-		};
+		struct perf_sample_data data;
+
+		perf_sample_data_init(&data, ~0ULL);
+		data.period = event->hw.last_period;
 
 		if (event->attr.sample_type & PERF_SAMPLE_ADDR)
 			perf_get_data_addr(regs, &data.addr);

arch/sparc/kernel/perf_event.c

@@ -1189,7 +1189,7 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self,
 
 	regs = args->regs;
 
-	data.addr = 0;
+	perf_sample_data_init(&data, 0);
 
 	cpuc = &__get_cpu_var(cpu_hw_events);
 

arch/x86/kernel/cpu/perf_event.c

@@ -1097,8 +1097,7 @@ static int x86_pmu_handle_irq(struct pt_regs *regs)
 	int idx, handled = 0;
 	u64 val;
 
-	data.addr = 0;
-	data.raw = NULL;
+	perf_sample_data_init(&data, 0);
 
 	cpuc = &__get_cpu_var(cpu_hw_events);
 

arch/x86/kernel/cpu/perf_event_intel.c

@@ -590,10 +590,9 @@ static void intel_pmu_drain_bts_buffer(void)
 
 	ds->bts_index = ds->bts_buffer_base;
 
+	perf_sample_data_init(&data, 0);
 
 	data.period	= event->hw.last_period;
-	data.addr	= 0;
-	data.raw	= NULL;
 	regs.ip		= 0;
 
 	/*
@@ -742,8 +741,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 	int bit, loops;
 	u64 ack, status;
 
-	data.addr = 0;
-	data.raw = NULL;
+	perf_sample_data_init(&data, 0);
 
 	cpuc = &__get_cpu_var(cpu_hw_events);
 

include/linux/perf_event.h

@@ -801,6 +801,13 @@ struct perf_sample_data {
 	struct perf_raw_record		*raw;
 };
 
+static inline
+void perf_sample_data_init(struct perf_sample_data *data, u64 addr)
+{
+	data->addr = addr;
+	data->raw  = NULL;
+}
+
 extern void perf_output_sample(struct perf_output_handle *handle,
 			       struct perf_event_header *header,
 			       struct perf_sample_data *data,

kernel/perf_event.c

@@ -4108,8 +4108,7 @@ void __perf_sw_event(u32 event_id, u64 nr, int nmi,
 	if (rctx < 0)
 		return;
 
-	data.addr = addr;
-	data.raw  = NULL;
+	perf_sample_data_init(&data, addr);
 
 	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
 
@@ -4157,8 +4156,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
 	event->pmu->read(event);
 
-	data.addr = 0;
-	data.raw = NULL;
+	perf_sample_data_init(&data, 0);
 	data.period = event->hw.last_period;
 	regs = get_irq_regs();
 	/*
@@ -4322,17 +4320,15 @@ static const struct pmu perf_ops_task_clock = {
 void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
 			  int entry_size)
 {
+	struct pt_regs *regs = get_irq_regs();
+	struct perf_sample_data data;
 	struct perf_raw_record raw = {
 		.size = entry_size,
 		.data = record,
 	};
 
-	struct perf_sample_data data = {
-		.addr = addr,
-		.raw = &raw,
-	};
-
-	struct pt_regs *regs = get_irq_regs();
+	perf_sample_data_init(&data, addr);
+	data.raw = &raw;
 
 	if (!regs)
 		regs = task_pt_regs(current);
@@ -4448,8 +4444,7 @@ void perf_bp_event(struct perf_event *bp, void *data)
 	struct perf_sample_data sample;
 	struct pt_regs *regs = data;
 
-	sample.raw = NULL;
-	sample.addr = bp->attr.bp_addr;
+	perf_sample_data_init(&sample, bp->attr.bp_addr);
 
 	if (!perf_exclude_event(bp, regs))
 		perf_swevent_add(bp, 1, 1, &sample, regs);