2023-06-28 11:53 UTC+0000 ~ Yafang Shao <laoar.shao@xxxxxxxxx>
> Enhance bpftool to display comprehensive information about exposed
> perf_event links, covering uprobe, kprobe, tracepoint, and generic perf
> event. The resulting output will include the following details:
>
> $ tools/bpf/bpftool/bpftool link show
> 3: perf_event prog 14
> event software:cpu-clock
> bpf_cookie 0
> pids perf_event(19483)
> 4: perf_event prog 14
> event hw-cache:LLC-load-misses
> bpf_cookie 0
> pids perf_event(19483)
> 5: perf_event prog 14
> event hardware:cpu-cycles
> bpf_cookie 0
> pids perf_event(19483)
> 6: perf_event prog 19
> tracepoint sched_switch
> bpf_cookie 0
> pids tracepoint(20947)
> 7: perf_event prog 26
> uprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
> bpf_cookie 0
> pids uprobe(21973)
> 8: perf_event prog 27
> uretprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
> bpf_cookie 0
> pids uprobe(21973)
> 10: perf_event prog 43
> kprobe ffffffffb70a9660 kernel_clone
> bpf_cookie 0
> pids kprobe(35275)
> 11: perf_event prog 41
> kretprobe ffffffffb70a9660 kernel_clone
> bpf_cookie 0
> pids kprobe(35275)
>
> $ tools/bpf/bpftool/bpftool link show -j
> [{"id":3,"type":"perf_event","prog_id":14,"event_type":"software","event_config":"cpu-clock","bpf_cookie":0,"pids":[{"pid":19483,"comm":"perf_event"}]},{"id":4,"type":"perf_event","prog_id":14,"event_type":"hw-cache","event_config":"LLC-load-misses","bpf_cookie":0,"pids":[{"pid":19483,"comm":"perf_event"}]},{"id":5,"type":"perf_event","prog_id":14,"event_type":"hardware","event_config":"cpu-cycles","bpf_cookie":0,"pids":[{"pid":19483,"comm":"perf_event"}]},{"id":6,"type":"perf_event","prog_id":19,"tracepoint":"sched_switch","bpf_cookie":0,"pids":[{"pid":20947,"comm":"tracepoint"}]},{"id":7,"type":"perf_event","prog_id":26,"retprobe":false,"file":"/home/dev/waken/bpf/uprobe/a.out","offset":4920,"bpf_cookie":0,"pids":[{"pid":21973,"comm":"uprobe"}]},{"id":8,"type":"perf_event","prog_id":27,"retprobe":true,"file":"/home/dev/waken/bpf/uprobe/a.out","offset":4920,"bpf_cookie":0,"pids":[{"pid":21973,"comm":"uprobe"}]},{"id":10,"type":"perf_event","prog_id":43,"retprobe":false,"addr":18446744072485508704,"func":"kernel_clone","offset":0,"bpf_cookie":0,"pids":[{"pid":35275,"comm":"kprobe"}]},{"id":11,"type":"perf_event","prog_id":41,"retprobe":true,"addr":18446744072485508704,"func":"kernel_clone","offset":0,"bpf_cookie":0,"pids":[{"pid":35275,"comm":"kprobe"}]}]
>
> For generic perf events, the displayed information in bpftool is limited to
> the type and configuration, while other attributes such as sample_period,
> sample_freq, etc., are not included.
>
> The kernel function address won't be exposed if it is not permitted by
> kptr_restrict. The result as follows when kptr_restrict is 2.
>
> $ tools/bpf/bpftool/bpftool link show
> 3: perf_event prog 14
> event software:cpu-clock
> 4: perf_event prog 14
> event hw-cache:LLC-load-misses
> 5: perf_event prog 14
> event hardware:cpu-cycles
> 6: perf_event prog 19
> tracepoint sched_switch
> 7: perf_event prog 26
> uprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
> 8: perf_event prog 27
> uretprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
> 10: perf_event prog 43
> kprobe kernel_clone
> 11: perf_event prog 41
> kretprobe kernel_clone
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
Thank you!
