On 7/23/15 2:42 AM, Kaixu Xia wrote:
According to the perf_event_map_fd and index, the function
bpf_perf_event_read() can convert the corresponding map
value to the pointer to struct perf_event and return the
Hardware PMU counter value.
Signed-off-by: Kaixu Xia <xiaka...@huawei.com>
...
+static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5)
+{
+ struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ struct perf_event *event;
+
+ if (index >= array->map.max_entries)
+ return -E2BIG;
+
+ event = array->events[index];
+ if (!event)
+ return -EBADF;
probably ENOENT makes more sense here.
+
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ return -ENOENT;
and -EINVAL here?
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