[PATCH 03/10] perf: Add new read_format bit to read build id faults

[Jiri Olsa]

It's now possible to retrieve build id faults stats by read
syscall on events with perf_event_attr::build_id set.

Adding PERF_FORMAT_BUILD_ID_FAULTS read_format bit to get
the value of build_id_faults through the read syscall.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 include/uapi/linux/perf_event.h | 17 ++++++++++-------
 kernel/events/core.c            | 21 ++++++++++++++++++---
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index f92880a15645..2424ba7f95fb 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -296,16 +296,18 @@ enum {
  *
  * struct read_format {
  *	{ u64		value;
- *	  { u64		time_enabled; } && PERF_FORMAT_TOTAL_TIME_ENABLED
- *	  { u64		time_running; } && PERF_FORMAT_TOTAL_TIME_RUNNING
- *	  { u64		id;           } && PERF_FORMAT_ID
+ *	  { u64		time_enabled;    } && PERF_FORMAT_TOTAL_TIME_ENABLED
+ *	  { u64		time_running;    } && PERF_FORMAT_TOTAL_TIME_RUNNING
+ *	  { u64		id;              } && PERF_FORMAT_ID
+ *	  { u64		build_id_faults; } && PERF_FORMAT_BUILD_ID_FAULTS
  *	} && !PERF_FORMAT_GROUP
  *
  *	{ u64		nr;
- *	  { u64		time_enabled; } && PERF_FORMAT_TOTAL_TIME_ENABLED
- *	  { u64		time_running; } && PERF_FORMAT_TOTAL_TIME_RUNNING
+ *	  { u64		time_enabled;    } && PERF_FORMAT_TOTAL_TIME_ENABLED
+ *	  { u64		time_running;    } && PERF_FORMAT_TOTAL_TIME_RUNNING
  *	  { u64		value;
- *	    { u64	id;           } && PERF_FORMAT_ID
+ *	    { u64	id;              } && PERF_FORMAT_ID
+ *	    { u64	build_id_faults; } && PERF_FORMAT_BUILD_ID_FAULTS
  *	  }		cntr[nr];
  *	} && PERF_FORMAT_GROUP
  * };
@@ -315,8 +317,9 @@ enum perf_event_read_format {
 	PERF_FORMAT_TOTAL_TIME_RUNNING		= 1U << 1,
 	PERF_FORMAT_ID				= 1U << 2,
 	PERF_FORMAT_GROUP			= 1U << 3,
+	PERF_FORMAT_BUILD_ID_FAULTS		= 1U << 4,
 
-	PERF_FORMAT_MAX = 1U << 4,		/* non-ABI */
+	PERF_FORMAT_MAX = 1U << 5,		/* non-ABI */
 };
 
 #define PERF_ATTR_SIZE_VER0	64	/* sizeof first published struct */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3f1630c06195..f3cd06012115 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1840,6 +1840,9 @@ static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
 	if (event->attr.read_format & PERF_FORMAT_ID)
 		entry += sizeof(u64);
 
+	if (event->attr.read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+		entry += sizeof(u64);
+
 	if (event->attr.read_format & PERF_FORMAT_GROUP) {
 		nr += nr_siblings;
 		size += sizeof(u64);
@@ -5247,11 +5250,15 @@ static int __perf_read_group_add(struct perf_event *leader,
 	values[n++] += perf_event_count(leader);
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(leader);
+	if (read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+		values[n++] = local64_read(&leader->build_id_faults);
 
 	for_each_sibling_event(sub, leader) {
 		values[n++] += perf_event_count(sub);
 		if (read_format & PERF_FORMAT_ID)
 			values[n++] = primary_event_id(sub);
+		if (read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+			values[n++] = local64_read(&sub->build_id_faults);
 	}
 
 	raw_spin_unlock_irqrestore(&ctx->lock, flags);
@@ -5308,7 +5315,7 @@ static int perf_read_one(struct perf_event *event,
 				 u64 read_format, char __user *buf)
 {
 	u64 enabled, running;
-	u64 values[4];
+	u64 values[5];
 	int n = 0;
 
 	values[n++] = __perf_event_read_value(event, &enabled, &running);
@@ -5318,6 +5325,8 @@ static int perf_read_one(struct perf_event *event,
 		values[n++] = running;
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(event);
+	if (read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+		values[n++] = local64_read(&event->build_id_faults);
 
 	if (copy_to_user(buf, values, n * sizeof(u64)))
 		return -EFAULT;
@@ -6820,7 +6829,7 @@ static void perf_output_read_one(struct perf_output_handle *handle,
 				 u64 enabled, u64 running)
 {
 	u64 read_format = event->attr.read_format;
-	u64 values[4];
+	u64 values[5];
 	int n = 0;
 
 	values[n++] = perf_event_count(event);
@@ -6834,6 +6843,8 @@ static void perf_output_read_one(struct perf_output_handle *handle,
 	}
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(event);
+	if (read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+		values[n++] = local64_read(&event->build_id_faults);
 
 	__output_copy(handle, values, n * sizeof(u64));
 }
@@ -6844,7 +6855,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 {
 	struct perf_event *leader = event->group_leader, *sub;
 	u64 read_format = event->attr.read_format;
-	u64 values[5];
+	u64 values[6];
 	int n = 0;
 
 	values[n++] = 1 + leader->nr_siblings;
@@ -6862,6 +6873,8 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 	values[n++] = perf_event_count(leader);
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(leader);
+	if (read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+		values[n++] = local64_read(&leader->build_id_faults);
 
 	__output_copy(handle, values, n * sizeof(u64));
 
@@ -6875,6 +6888,8 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 		values[n++] = perf_event_count(sub);
 		if (read_format & PERF_FORMAT_ID)
 			values[n++] = primary_event_id(sub);
+		if (read_format & PERF_FORMAT_BUILD_ID_FAULTS)
+			values[n++] = local64_read(&sub->build_id_faults);
 
 		__output_copy(handle, values, n * sizeof(u64));
 	}
-- 
2.31.1