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Commit 97562633 authored by Yonghong Song's avatar Yonghong Song Committed by David S. Miller
Browse files

bpf: perf event change needed for subsequent bpf helpers 



This patch does not impact existing functionalities.
It contains the changes in perf event area needed for
subsequent bpf_perf_event_read_value and
bpf_perf_prog_read_value helpers.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bdc47641

include/linux/perf_event.h

+5 −2
Original line number Diff line number Diff line
@@ -806,6 +806,7 @@ struct perf_output_handle { 
struct bpf_perf_event_data_kern {

	struct pt_regs *regs;

	struct perf_sample_data *data;

	struct perf_event *event;

};



#ifdef CONFIG_CGROUP_PERF
@@ -884,7 +885,8 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, 
				void *context);

extern void perf_pmu_migrate_context(struct pmu *pmu,

				int src_cpu, int dst_cpu);

int perf_event_read_local(struct perf_event *event, u64 *value);

int perf_event_read_local(struct perf_event *event, u64 *value,

			  u64 *enabled, u64 *running);

extern u64 perf_event_read_value(struct perf_event *event,

				 u64 *enabled, u64 *running);
@@ -1286,7 +1288,8 @@ static inline const struct perf_event_attr *perf_event_attrs(struct perf_event * 
{

	return ERR_PTR(-EINVAL);

}

static inline int perf_event_read_local(struct perf_event *event, u64 *value)

static inline int perf_event_read_local(struct perf_event *event, u64 *value,

					u64 *enabled, u64 *running)

{

	return -EINVAL;

}

kernel/bpf/arraymap.c

+1 −1
Original line number Diff line number Diff line
@@ -492,7 +492,7 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map, 


	ee = ERR_PTR(-EOPNOTSUPP);

	event = perf_file->private_data;

	if (perf_event_read_local(event, &value) == -EOPNOTSUPP)

	if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)

		goto err_out;



	ee = bpf_event_entry_gen(perf_file, map_file);

kernel/events/core.c

+13 −2
Original line number Diff line number Diff line
@@ -3684,10 +3684,12 @@ static inline u64 perf_event_count(struct perf_event *event) 
 *     will not be local and we cannot read them atomically

 *   - must not have a pmu::count method

 */

int perf_event_read_local(struct perf_event *event, u64 *value)

int perf_event_read_local(struct perf_event *event, u64 *value,

			  u64 *enabled, u64 *running)

{

	unsigned long flags;

	int ret = 0;

	u64 now;



	/*

	 * Disabling interrupts avoids all counter scheduling (context
@@ -3718,13 +3720,21 @@ int perf_event_read_local(struct perf_event *event, u64 *value) 
		goto out;

	}



	now = event->shadow_ctx_time + perf_clock();

	if (enabled)

		*enabled = now - event->tstamp_enabled;

	/*

	 * If the event is currently on this CPU, its either a per-task event,

	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise

	 * oncpu == -1).

	 */

	if (event->oncpu == smp_processor_id())

	if (event->oncpu == smp_processor_id()) {

		event->pmu->read(event);

		if (running)

			*running = now - event->tstamp_running;

	} else if (running) {

		*running = event->total_time_running;

	}



	*value = local64_read(&event->count);

out:
@@ -8072,6 +8082,7 @@ static void bpf_overflow_handler(struct perf_event *event, 
	struct bpf_perf_event_data_kern ctx = {

		.data = data,

		.regs = regs,

		.event = event,

	};

	int ret = 0;

kernel/trace/bpf_trace.c

+1 −1
Original line number Diff line number Diff line
@@ -275,7 +275,7 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 
	if (!ee)

		return -ENOENT;



	err = perf_event_read_local(ee->event, &value);

	err = perf_event_read_local(ee->event, &value, NULL, NULL);

	/*

	 * this api is ugly since we miss [-22..-2] range of valid

	 * counter values, but that's uapi