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bpftool: Show perf link info

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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>
This commit is contained in:
Yafang Shao 2023-07-09 02:56:30 +00:00 committed by Alexei Starovoitov
parent 62b57e3ddd
commit 88d6160737
1 changed files with 246 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

247
tools/bpf/bpftool/link.c
View File

@ -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;
@ -279,6 +281,110 @@ show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
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.type == BPF_PERF_EVENT_KRETPROBE);
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.type == BPF_PERF_EVENT_URETPROBE);
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;
@ -334,6 +440,26 @@ 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:
case BPF_PERF_EVENT_KRETPROBE:
show_perf_event_kprobe_json(info, json_wtr);
break;
case BPF_PERF_EVENT_UPROBE:
case BPF_PERF_EVENT_URETPROBE:
show_perf_event_uprobe_json(info, json_wtr);
break;
default:
break;
}
break;
default:
break;
}
@ -505,6 +631,75 @@ 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 = u64_to_ptr(info->perf_event.kprobe.func_name);
if (buf[0] == '\0' && !info->perf_event.kprobe.addr)
return;
if (info->perf_event.type == BPF_PERF_EVENT_KRETPROBE)
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 = u64_to_ptr(info->perf_event.uprobe.file_name);
if (buf[0] == '\0')
return;
if (info->perf_event.type == BPF_PERF_EVENT_URETPROBE)
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 = 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;
@ -553,6 +748,26 @@ 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:
case BPF_PERF_EVENT_KRETPROBE:
show_perf_event_kprobe_plain(info);
break;
case BPF_PERF_EVENT_UPROBE:
case BPF_PERF_EVENT_URETPROBE:
show_perf_event_uprobe_plain(info);
break;
default:
break;
}
break;
default:
break;
}
@ -575,11 +790,12 @@ 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) {
@ -614,6 +830,35 @@ again:
goto again;
}
}
if (info.type == BPF_LINK_TYPE_PERF_EVENT) {
switch (info.perf_event.type) {
case BPF_PERF_EVENT_TRACEPOINT:
if (!info.perf_event.tracepoint.tp_name) {
info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
info.perf_event.tracepoint.name_len = sizeof(buf);
goto again;
}
break;
case BPF_PERF_EVENT_KPROBE:
case BPF_PERF_EVENT_KRETPROBE:
if (!info.perf_event.kprobe.func_name) {
info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
info.perf_event.kprobe.name_len = sizeof(buf);
goto again;
}
break;
case BPF_PERF_EVENT_UPROBE:
case BPF_PERF_EVENT_URETPROBE:
if (!info.perf_event.uprobe.file_name) {
info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
info.perf_event.uprobe.name_len = sizeof(buf);
goto again;
}
break;
default:
break;
}
}
if (json_output)
show_link_close_json(fd, &info);