From: Quentin Monnet <quentin@isovalent.com>
To: Yafang Shao <laoar.shao@gmail.com>,
ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yhs@fb.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, rostedt@goodmis.org,
mhiramat@kernel.org
Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v5 bpf-next 11/11] bpftool: Show perf link info
Date: Fri, 23 Jun 2023 17:49:11 +0100 [thread overview]
Message-ID: <47769c5d-e6da-1f60-aac5-42c7322485fd@isovalent.com> (raw)
In-Reply-To: <20230623141546.3751-12-laoar.shao@gmail.com>
2023-06-23 14:15 UTC+0000 ~ Yafang Shao <laoar.shao@gmail.com>
> 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 <laoar.shao@gmail.com>
> ---
> 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 e5aeee3..31bee95 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;
This "if (...) goto out;" seems unnecessary? If info.perf_event.type is
BPF_PERF_EVENT_EVENT we won't match any of the conditions below and
should reach the "out:" label anyway (and that label seems also
unnecessary)?
> + 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
next prev parent reply other threads:[~2023-06-23 16:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-23 14:15 [PATCH v5 bpf-next 00/11] bpf: Support ->fill_link_info for kprobe_multi and perf_event links Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 01/11] bpf: Support ->fill_link_info for kprobe_multi Yafang Shao
2023-06-23 21:45 ` Andrii Nakryiko
2023-06-25 14:34 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 02/11] bpftool: Dump the kernel symbol's module name Yafang Shao
2023-06-23 16:48 ` Quentin Monnet
2023-06-23 14:15 ` [PATCH v5 bpf-next 03/11] bpftool: Show kprobe_multi link info Yafang Shao
2023-06-23 16:48 ` Quentin Monnet
2023-06-25 14:29 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 04/11] bpf: Protect probed address based on kptr_restrict setting Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 05/11] bpf: Clear the probe_addr for uprobe Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 06/11] bpf: Expose symbol's respective address Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 07/11] bpf: Add a common helper bpf_copy_to_user() Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 08/11] bpf: Add bpf_perf_link_fill_common() Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 09/11] bpf: Support ->fill_link_info for perf_event Yafang Shao
2023-06-23 21:55 ` Andrii Nakryiko
2023-06-25 14:35 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 10/11] bpftool: Add perf event names Yafang Shao
2023-06-23 16:49 ` Quentin Monnet
2023-06-25 14:30 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 11/11] bpftool: Show perf link info Yafang Shao
2023-06-23 16:49 ` Quentin Monnet [this message]
2023-06-25 14:31 ` Yafang Shao
2023-06-23 17:13 ` Alexei Starovoitov
2023-06-25 14:32 ` Yafang Shao
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