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>

7 files changed, 25 insertions, 26 deletions

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index c54ceb3d1f97..3875d99cc40f 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/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) {
diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
index b6cf8f1f4d35..5120bd44f69a 100644
--- a/arch/powerpc/kernel/perf_event.c
+++ b/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);
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 9f2b2bac8b2b..6504208f375f 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/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);
 
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 97cddbf32936..42aafd11e170 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/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);
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 73102df8bfc1..44b60c852107 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/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);
 
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 90e0521b1690..6f8cd7da1a01 100644
--- a/include/linux/perf_event.h
+++ b/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,
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index e68745053013..4393b9e73740 100644
--- a/kernel/perf_event.c
+++ b/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);
 
@@ -4154,11 +4153,10 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
         struct perf_event *event;
         u64 period;
 
-        event   = container_of(hrtimer, struct perf_event, hw.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);