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The resulting output will include the following details: $ tools/bpf/bpftool/bpftool link show 3: perf_event prog 14 event_type software event_config cpu-clock bpf_cookie 0 pids perf_event(1379330) 4: perf_event prog 14 event_type hw-cache event_config LLC-load-misses bpf_cookie 0 pids perf_event(1379330) 5: perf_event prog 14 event_type hardware event_config cpu-cycles bpf_cookie 0 pids perf_event(1379330) 6: perf_event prog 20 retprobe 0 file_name /home/yafang/bpf/uprobe/a.out offset 0x1338 bpf_cookie 0 pids uprobe(1379706) 7: perf_event prog 21 retprobe 1 file_name /home/yafang/bpf/uprobe/a.out offset 0x1338 bpf_cookie 0 pids uprobe(1379706) 8: perf_event prog 27 tp_name sched_switch bpf_cookie 0 pids tracepoint(1381734) 10: perf_event prog 43 retprobe 0 func_name kernel_clone addr ffffffffad0a9660 bpf_cookie 0 pids kprobe(1384186) 11: perf_event prog 41 retprobe 1 func_name kernel_clone addr ffffffffad0a9660 bpf_cookie 0 pids kprobe(1384186) $ tools/bpf/bpftool/bpftool link show -j [{"id":3,"type":"perf_event","prog_id":14,"event_type":"software","event_co= nfig":"cpu-clock","bpf_cookie":0,"pids":[{"pid":1379330,"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":1379330,"comm":"pe= rf_event"}]},{"id":5,"type":"perf_event","prog_id":14,"event_type":"hardwar= e","event_config":"cpu-cycles","bpf_cookie":0,"pids":[{"pid":1379330,"comm"= :"perf_event"}]},{"id":6,"type":"perf_event","prog_id":20,"retprobe":0,"fil= e_name":"/home/yafang/bpf/uprobe/a.out","offset":4920,"bpf_cookie":0,"pids"= :[{"pid":1379706,"comm":"uprobe"}]},{"id":7,"type":"perf_event","prog_id":2= 1,"retprobe":1,"file_name":"/home/yafang/bpf/uprobe/a.out","offset":4920,"b= pf_cookie":0,"pids":[{"pid":1379706,"comm":"uprobe"}]},{"id":8,"type":"perf= _event","prog_id":27,"tp_name":"sched_switch","bpf_cookie":0,"pids":[{"pid"= :1381734,"comm":"tracepoint"}]},{"id":10,"type":"perf_event","prog_id":43,"= retprobe":0,"func_name":"kernel_clone","offset":0,"addr":184467440723177365= 44,"bpf_cookie":0,"pids":[{"pid":1384186,"comm":"kprobe"}]},{"id":11,"type"= :"perf_event","prog_id":41,"retprobe":1,"func_name":"kernel_clone","offset"= :0,"addr":18446744072317736544,"bpf_cookie":0,"pids":[{"pid":1384186,"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_type software event_config cpu-clock 4: perf_event prog 14 event_type hw-cache event_config LLC-load-misses 5: perf_event prog 14 event_type hardware event_config cpu-cycles 6: perf_event prog 20 retprobe 0 file_name /home/yafang/bpf/uprobe/a.out offset 0x1338 7: perf_event prog 21 retprobe 1 file_name /home/yafang/bpf/uprobe/a.out offset 0x1338 8: perf_event prog 27 tp_name sched_switch 10: perf_event prog 43 retprobe 0 func_name kernel_clone 11: perf_event prog 41 retprobe 1 func_name kernel_clone Signed-off-by: Yafang Shao --- tools/bpf/bpftool/link.c | 213 +++++++++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 213 insertions(+) diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index 0015582..c16f71d 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -15,6 +15,7 @@ #include "json_writer.h" #include "main.h" #include "xlated_dumper.h" +#include "perf.h" =20 static struct hashmap *link_table; static struct dump_data dd =3D {}; @@ -207,6 +208,109 @@ static int cmp_u64(const void *A, const void *B) jsonw_end_array(json_wtr); } =20 +static void +show_perf_event_kprobe_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_uint_field(wtr, "retprobe", info->kprobe.flags & 0x1); + jsonw_string_field(wtr, "func_name", + u64_to_ptr(info->kprobe.func_name)); + jsonw_uint_field(wtr, "offset", info->kprobe.offset); + jsonw_uint_field(wtr, "addr", info->kprobe.addr); +} + +static void +show_perf_event_uprobe_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_uint_field(wtr, "retprobe", info->uprobe.flags & 0x1); + jsonw_string_field(wtr, "file_name", + u64_to_ptr(info->uprobe.file_name)); + jsonw_uint_field(wtr, "offset", info->uprobe.offset); +} + +static void +show_perf_event_tp_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_string_field(wtr, "tp_name", + u64_to_ptr(info->tracepoint.tp_name)); +} + +static const char *perf_config_hw_cache_str(__u64 config) +{ +#define PERF_HW_CACHE_LEN 128 + const char *hw_cache, *result, *op; + char *str =3D malloc(PERF_HW_CACHE_LEN); + + if (!str) { + p_err("mem alloc failed"); + return NULL; + } + hw_cache =3D perf_hw_cache_str(config & 0xff); + if (hw_cache) + snprintf(str, PERF_HW_CACHE_LEN, "%s-", hw_cache); + else + snprintf(str, PERF_HW_CACHE_LEN, "%lld-", config & 0xff); + op =3D perf_hw_cache_op_str((config >> 8) & 0xff); + if (op) + snprintf(str + strlen(str), PERF_HW_CACHE_LEN - strlen(str), + "%s-", op); + else + snprintf(str + strlen(str), PERF_HW_CACHE_LEN - strlen(str), + "%lld-", (config >> 8) & 0xff); + result =3D perf_hw_cache_op_result_str(config >> 16); + if (result) + snprintf(str + strlen(str), PERF_HW_CACHE_LEN - strlen(str), + "%s", result); + else + snprintf(str + strlen(str), PERF_HW_CACHE_LEN - strlen(str), + "%lld", config >> 16); + + return str; +} + +static const char *perf_config_str(__u32 type, __u64 config) +{ + const char *perf_config; + + switch (type) { + case PERF_TYPE_HARDWARE: + perf_config =3D perf_hw_str(config); + break; + case PERF_TYPE_SOFTWARE: + perf_config =3D perf_sw_str(config); + break; + case PERF_TYPE_HW_CACHE: + perf_config =3D perf_config_hw_cache_str(config); + break; + default: + perf_config =3D NULL; + break; + } + return perf_config; +} + +static void +show_perf_event_event_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + __u64 config =3D info->perf_event.config; + __u32 type =3D info->perf_event.type; + const char *perf_type, *perf_config; + + perf_type =3D perf_type_str(type); + if (perf_type) + jsonw_string_field(wtr, "event_type", perf_type); + else + jsonw_uint_field(wtr, "event_type", type); + + perf_config =3D perf_config_str(type, config); + if (perf_config) + jsonw_string_field(wtr, "event_config", perf_config); + else + jsonw_uint_field(wtr, "event_config", config); + + if (type =3D=3D PERF_TYPE_HW_CACHE && perf_config) + free((void *)perf_config); +} + static int show_link_close_json(int fd, struct bpf_link_info *info) { struct bpf_prog_info prog_info; @@ -262,6 +366,16 @@ static int show_link_close_json(int fd, struct bpf_lin= k_info *info) case BPF_LINK_TYPE_KPROBE_MULTI: show_kprobe_multi_json(info, json_wtr); break; + case BPF_LINK_TYPE_PERF_EVENT: + if (info->perf_link_type =3D=3D BPF_PERF_LINK_PERF_EVENT) + show_perf_event_event_json(info, json_wtr); + else if (info->perf_link_type =3D=3D BPF_PERF_LINK_TRACEPOINT) + show_perf_event_tp_json(info, json_wtr); + else if (info->perf_link_type =3D=3D BPF_PERF_LINK_KPROBE) + show_perf_event_kprobe_json(info, json_wtr); + else if (info->perf_link_type =3D=3D BPF_PERF_LINK_UPROBE) + show_perf_event_uprobe_json(info, json_wtr); + break; default: break; } @@ -433,6 +547,71 @@ static void show_kprobe_multi_plain(struct bpf_link_in= fo *info) } } =20 +static void show_perf_event_kprobe_plain(struct bpf_link_info *info) +{ + const char *buf; + __u32 retprobe; + + buf =3D (const char *)u64_to_ptr(info->kprobe.func_name); + if (buf[0] =3D=3D '\0' && !info->kprobe.addr) + return; + + retprobe =3D info->kprobe.flags & 0x1; + printf("\n\tretprobe %u func_name %s ", retprobe, buf); + if (info->kprobe.offset) + printf("offset %#x ", info->kprobe.offset); + if (info->kprobe.addr) + printf("addr %llx ", info->kprobe.addr); +} + +static void show_perf_event_uprobe_plain(struct bpf_link_info *info) +{ + const char *buf; + __u32 retprobe; + + buf =3D (const char *)u64_to_ptr(info->uprobe.file_name); + if (buf[0] =3D=3D '\0') + return; + + retprobe =3D info->uprobe.flags & 0x1; + printf("\n\tretprobe %u file_name %s ", retprobe, buf); + if (info->uprobe.offset) + printf("offset %#x ", info->kprobe.offset); +} + +static void show_perf_event_tp_plain(struct bpf_link_info *info) +{ + const char *buf; + + buf =3D (const char *)u64_to_ptr(info->tracepoint.tp_name); + if (buf[0] =3D=3D '\0') + return; + + printf("\n\ttp_name %s ", buf); +} + +static void show_perf_event_event_plain(struct bpf_link_info *info) +{ + __u64 config =3D info->perf_event.config; + __u32 type =3D info->perf_event.type; + const char *perf_type, *perf_config; + + perf_type =3D perf_type_str(type); + if (perf_type) + printf("\n\tevent_type %s ", perf_type); + else + printf("\n\tevent_type %u ", type); + + perf_config =3D perf_config_str(type, config); + if (perf_config) + printf("event_config %s ", perf_config); + else + printf("event_config %llu ", config); + + if (type =3D=3D PERF_TYPE_HW_CACHE && perf_config) + free((void *)perf_config); +} + static int show_link_close_plain(int fd, struct bpf_link_info *info) { struct bpf_prog_info prog_info; @@ -481,6 +660,16 @@ static int show_link_close_plain(int fd, struct bpf_li= nk_info *info) case BPF_LINK_TYPE_KPROBE_MULTI: show_kprobe_multi_plain(info); break; + case BPF_LINK_TYPE_PERF_EVENT: + if (info->perf_link_type =3D=3D BPF_PERF_LINK_PERF_EVENT) + show_perf_event_event_plain(info); + else if (info->perf_link_type =3D=3D BPF_PERF_LINK_TRACEPOINT) + show_perf_event_tp_plain(info); + else if (info->perf_link_type =3D=3D BPF_PERF_LINK_KPROBE) + show_perf_event_kprobe_plain(info); + else if (info->perf_link_type =3D=3D BPF_PERF_LINK_UPROBE) + show_perf_event_uprobe_plain(info); + break; default: break; } @@ -508,6 +697,7 @@ static int do_show_link(int fd) int err; =20 memset(&info, 0, sizeof(info)); + buf[0] =3D '\0'; again: err =3D bpf_link_get_info_by_fd(fd, &info, &len); if (err) { @@ -542,7 +732,30 @@ static int do_show_link(int fd) goto again; } } + if (info.type =3D=3D BPF_LINK_TYPE_PERF_EVENT) { + if (info.perf_link_type =3D=3D BPF_PERF_LINK_PERF_EVENT) + goto out; + if (info.perf_link_type =3D=3D BPF_PERF_LINK_TRACEPOINT && + !info.tracepoint.tp_name) { + info.tracepoint.tp_name =3D (unsigned long)&buf; + info.tracepoint.name_len =3D sizeof(buf); + goto again; + } + if (info.perf_link_type =3D=3D BPF_PERF_LINK_KPROBE && + !info.kprobe.func_name) { + info.kprobe.func_name =3D (unsigned long)&buf; + info.kprobe.name_len =3D sizeof(buf); + goto again; + } + if (info.perf_link_type =3D=3D BPF_PERF_LINK_UPROBE && + !info.uprobe.file_name) { + info.uprobe.file_name =3D (unsigned long)&buf; + info.uprobe.name_len =3D sizeof(buf); + goto again; + } + } =20 +out: if (json_output) show_link_close_json(fd, &info); else --=20 1.8.3.1