bpftool: Show perf link info
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@gmail.com> Reviewed-by:
Quentin Monnet <quentin@isovalent.com> Acked-by:
Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230709025630.3735-11-laoar.shao@gmail.com Signed-off-by:
Alexei Starovoitov <ast@kernel.org>
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