[PATCH v4 bpf-next 11/11] bpftool: Show perf link info
From: Yafang Shao <hidden>
Date: 2023-06-20 16:30:42
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [tooling] (bpftool), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Quentin Monnet, Linus Torvalds
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
4: perf_event prog 23
uprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
bpf_cookie 0
pids uprobe(27503)
5: perf_event prog 24
uretprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
bpf_cookie 0
pids uprobe(27503)
6: perf_event prog 31
kprobe ffffffffa90a9660 kernel_clone
bpf_cookie 0
pids kprobe(27777)
7: perf_event prog 30
kretprobe ffffffffa90a9660 kernel_clone
bpf_cookie 0
pids kprobe(27777)
8: perf_event prog 37
tracepoint sched_switch
bpf_cookie 0
pids tracepoint(28036)
9: perf_event prog 43
event software:cpu-clock
bpf_cookie 0
pids perf_event(28261)
10: perf_event prog 43
event hw-cache:LLC-load-misses
bpf_cookie 0
pids perf_event(28261)
11: perf_event prog 43
event hardware:cpu-cycles
bpf_cookie 0
pids perf_event(28261)
$ tools/bpf/bpftool/bpftool link show -j
[{"id":4,"type":"perf_event","prog_id":23,"retprobe":false,"file":"/home/dev/waken/bpf/uprobe/a.out","offset":4920,"bpf_cookie":0,"pids":[{"pid":27503,"comm":"uprobe"}]},{"id":5,"type":"perf_event","prog_id":24,"retprobe":true,"file":"/home/dev/waken/bpf/uprobe/a.out","offset":4920,"bpf_cookie":0,"pids":[{"pid":27503,"comm":"uprobe"}]},{"id":6,"type":"perf_event","prog_id":31,"retprobe":false,"addr":18446744072250627680,"func":"kernel_clone","offset":0,"bpf_cookie":0,"pids":[{"pid":27777,"comm":"kprobe"}]},{"id":7,"type":"perf_event","prog_id":30,"retprobe":true,"addr":18446744072250627680,"func":"kernel_clone","offset":0,"bpf_cookie":0,"pids":[{"pid":27777,"comm":"kprobe"}]},{"id":8,"type":"perf_event","prog_id":37,"tracepoint":"sched_switch","bpf_cookie":0,"pids":[{"pid":28036,"comm":"tracepoint"}]},{"id":9,"type":"perf_event","prog_id":43,"event_type":"software","event_config":"cpu-clock","bpf_cookie":0,"pids":[{"pid":28261,"comm":"perf_event"}]},{"id":10,"type":"perf_event","prog_id":43,"event_type":"hw-cache","event_config":"LLC-load-misses","bpf_cookie":0,"pids":[{"pid":28261,"comm":"perf_event"}]},{"id":11,"type":"perf_event","prog_id":43,"event_type":"hardware","event_config":"cpu-cycles","bpf_cookie":0,"pids":[{"pid":28261,"comm":"perf_event"}]}]
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
4: perf_event prog 23
uprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
5: perf_event prog 24
uretprobe /home/dev/waken/bpf/uprobe/a.out+0x1338
6: perf_event prog 31
kprobe kernel_clone
7: perf_event prog 30
kretprobe kernel_clone
8: perf_event prog 37
tracepoint sched_switch
9: perf_event prog 43
event software:cpu-clock
10: perf_event prog 43
event hw-cache:LLC-load-misses
11: perf_event prog 43
event hardware:cpu-cycles
Signed-off-by: Yafang Shao <redacted>
---
tools/bpf/bpftool/link.c | 237 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 236 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 9274d59..0173d4e 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c@@ -17,6 +17,8 @@ #include "main.h" #include "xlated_dumper.h" +#define PERF_HW_CACHE_LEN 128 + static struct hashmap *link_table; static struct dump_data dd = {};
@@ -274,6 +276,110 @@ static int cmp_u64(const void *A, const void *B) jsonw_end_array(json_wtr); } +static void +show_perf_event_kprobe_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_bool_field(wtr, "retprobe", info->perf_event.kprobe.flags & 0x1); + jsonw_uint_field(wtr, "addr", info->perf_event.kprobe.addr); + jsonw_string_field(wtr, "func", + u64_to_ptr(info->perf_event.kprobe.func_name)); + jsonw_uint_field(wtr, "offset", info->perf_event.kprobe.offset); +} + +static void +show_perf_event_uprobe_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_bool_field(wtr, "retprobe", info->perf_event.uprobe.flags & 0x1); + jsonw_string_field(wtr, "file", + u64_to_ptr(info->perf_event.uprobe.file_name)); + jsonw_uint_field(wtr, "offset", info->perf_event.uprobe.offset); +} + +static void +show_perf_event_tracepoint_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_string_field(wtr, "tracepoint", + u64_to_ptr(info->perf_event.tracepoint.tp_name)); +} + +static char *perf_config_hw_cache_str(__u64 config) +{ + const char *hw_cache, *result, *op; + char *str = malloc(PERF_HW_CACHE_LEN); + + if (!str) { + p_err("mem alloc failed"); + return NULL; + } + + hw_cache = perf_event_name(evsel__hw_cache, 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 = perf_event_name(evsel__hw_cache_op, (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 = perf_event_name(evsel__hw_cache_result, 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 = perf_event_name(event_symbols_hw, config); + break; + case PERF_TYPE_SOFTWARE: + perf_config = perf_event_name(event_symbols_sw, config); + break; + case PERF_TYPE_HW_CACHE: + perf_config = perf_config_hw_cache_str(config); + break; + default: + perf_config = NULL; + break; + } + return perf_config; +} + +static void +show_perf_event_event_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + __u64 config = info->perf_event.event.config; + __u32 type = info->perf_event.event.type; + const char *perf_type, *perf_config; + + perf_type = perf_event_name(perf_type_name, type); + if (perf_type) + jsonw_string_field(wtr, "event_type", perf_type); + else + jsonw_uint_field(wtr, "event_type", type); + + perf_config = 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 == 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;
@@ -329,6 +435,24 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) case BPF_LINK_TYPE_KPROBE_MULTI: show_kprobe_multi_json(info, json_wtr); break; + case BPF_LINK_TYPE_PERF_EVENT: + switch (info->perf_event.type) { + case BPF_PERF_EVENT_EVENT: + show_perf_event_event_json(info, json_wtr); + break; + case BPF_PERF_EVENT_TRACEPOINT: + show_perf_event_tracepoint_json(info, json_wtr); + break; + case BPF_PERF_EVENT_KPROBE: + show_perf_event_kprobe_json(info, json_wtr); + break; + case BPF_PERF_EVENT_UPROBE: + show_perf_event_uprobe_json(info, json_wtr); + break; + default: + break; + } + break; default: break; }
@@ -500,6 +624,75 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info) } } +static void show_perf_event_kprobe_plain(struct bpf_link_info *info) +{ + const char *buf; + + buf = (const char *)u64_to_ptr(info->perf_event.kprobe.func_name); + if (buf[0] == '\0' && !info->perf_event.kprobe.addr) + return; + + if (info->perf_event.kprobe.flags & 0x1) + printf("\n\tkretprobe "); + else + printf("\n\tkprobe "); + if (info->perf_event.kprobe.addr) + printf("%llx ", info->perf_event.kprobe.addr); + printf("%s", buf); + if (info->perf_event.kprobe.offset) + printf("+%#x", info->perf_event.kprobe.offset); + printf(" "); +} + +static void show_perf_event_uprobe_plain(struct bpf_link_info *info) +{ + const char *buf; + + buf = (const char *)u64_to_ptr(info->perf_event.uprobe.file_name); + if (buf[0] == '\0') + return; + + if (info->perf_event.uprobe.flags & 0x1) + printf("\n\turetprobe "); + else + printf("\n\tuprobe "); + printf("%s+%#x ", buf, info->perf_event.uprobe.offset); +} + +static void show_perf_event_tracepoint_plain(struct bpf_link_info *info) +{ + const char *buf; + + buf = (const char *)u64_to_ptr(info->perf_event.tracepoint.tp_name); + if (buf[0] == '\0') + return; + + printf("\n\ttracepoint %s ", buf); +} + +static void show_perf_event_event_plain(struct bpf_link_info *info) +{ + __u64 config = info->perf_event.event.config; + __u32 type = info->perf_event.event.type; + const char *perf_type, *perf_config; + + printf("\n\tevent "); + perf_type = perf_event_name(perf_type_name, type); + if (perf_type) + printf("%s:", perf_type); + else + printf("%u :", type); + + perf_config = perf_config_str(type, config); + if (perf_config) + printf("%s ", perf_config); + else + printf("%llu ", config); + + if (type == 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;
@@ -548,6 +741,24 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info) case BPF_LINK_TYPE_KPROBE_MULTI: show_kprobe_multi_plain(info); break; + case BPF_LINK_TYPE_PERF_EVENT: + switch (info->perf_event.type) { + case BPF_PERF_EVENT_EVENT: + show_perf_event_event_plain(info); + break; + case BPF_PERF_EVENT_TRACEPOINT: + show_perf_event_tracepoint_plain(info); + break; + case BPF_PERF_EVENT_KPROBE: + show_perf_event_kprobe_plain(info); + break; + case BPF_PERF_EVENT_UPROBE: + show_perf_event_uprobe_plain(info); + break; + default: + break; + } + break; default: break; }
@@ -570,11 +781,12 @@ static int do_show_link(int fd) struct bpf_link_info info; __u32 len = sizeof(info); __u64 *addrs = NULL; - char buf[256]; + char buf[PATH_MAX]; int count; int err; memset(&info, 0, sizeof(info)); + buf[0] = '\0'; again: err = bpf_link_get_info_by_fd(fd, &info, &len); if (err) {
@@ -609,7 +821,30 @@ static int do_show_link(int fd) goto again; } } + if (info.type == BPF_LINK_TYPE_PERF_EVENT) { + if (info.perf_event.type == BPF_PERF_EVENT_EVENT) + goto out; + if (info.perf_event.type == BPF_PERF_EVENT_TRACEPOINT && + !info.perf_event.tracepoint.tp_name) { + info.perf_event.tracepoint.tp_name = (unsigned long)&buf; + info.perf_event.tracepoint.name_len = sizeof(buf); + goto again; + } + if (info.perf_event.type == BPF_PERF_EVENT_KPROBE && + !info.perf_event.kprobe.func_name) { + info.perf_event.kprobe.func_name = (unsigned long)&buf; + info.perf_event.kprobe.name_len = sizeof(buf); + goto again; + } + if (info.perf_event.type == BPF_PERF_EVENT_UPROBE && + !info.perf_event.uprobe.file_name) { + info.perf_event.uprobe.file_name = (unsigned long)&buf; + info.perf_event.uprobe.name_len = sizeof(buf); + goto again; + } + } +out: if (json_output) show_link_close_json(fd, &info); else
--
1.8.3.1