[PATCH V3 2/2] bpf: control all the perf events stored in PERF_EVENT_ARRAY maps
STALE4001d
From: Kaixu Xia <hidden>
Date: 2015-10-16 07:42:45
Also in:
lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [security & lsm] (security audit and enforcement using bpf), bpf [tracing], the rest, tracing · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
This patch implements the function that controlling all the perf events stored in PERF_EVENT_ARRAY maps by setting the parameter 'index' to maps max_entries. Signed-off-by: Kaixu Xia <redacted> --- kernel/trace/bpf_trace.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 3175600..4b385863 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c@@ -229,13 +229,30 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, u64 flag, u64 r4, u64 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; + int i; - if (unlikely(index >= array->map.max_entries)) + if (unlikely(index > array->map.max_entries)) return -E2BIG; if (flag & BIT_FLAG_CHECK) return -EINVAL; + if (index == array->map.max_entries) { + bool dump_control = flag & BIT_DUMP_CTL; + + for (i = 0; i < array->map.max_entries; i++) { + event = (struct perf_event *)array->ptrs[i]; + if (!event) + continue; + + if (dump_control) + atomic_dec_if_positive(&event->dump_enable); + else + atomic_inc_unless_negative(&event->dump_enable); + } + return 0; + } + event = (struct perf_event *)array->ptrs[index]; if (!event) return -ENOENT;
@@ -244,7 +261,6 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, u64 flag, u64 r4, u64 atomic_dec_if_positive(&event->dump_enable); else atomic_inc_unless_negative(&event->dump_enable); - return 0; }
--
1.8.3.4