Quentin reported build warnings when building bpftool :

    link.c: In function ‘perf_config_hw_cache_str’:
    link.c:86:18: warning: comparison of unsigned expression in ‘>= 0’ is always true [-Wtype-limits]
       86 |         if ((id) >= 0 && (id) < ARRAY_SIZE(array))      \
          |                  ^~
    link.c:320:20: note: in expansion of macro ‘perf_event_name’
      320 |         hw_cache = perf_event_name(evsel__hw_cache, config & 0xff);
          |                    ^~~~~~~~~~~~~~~
    [... more of the same for the other calls to perf_event_name ...]

He also pointed out the reason and the solution:

  We're always passing unsigned, so it should be safe to drop the check on
  (id) >= 0.

Fixes: 62b57e3ddd64 ("bpftool: Add perf event names")
Reported-by: Quentin Monnet <quentin@isovalent.com>
Suggested-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Closes: https://lore.kernel.org/bpf/a35d9a2d-54a0-49ec-9ed1-8fcf1369d3cc@isovalent.com
Link: https://lore.kernel.org/bpf/20230830030325.3786-1-laoar.shao@gmail.com

Add support to dump XDP link information to bpftool. This reuses the
recently added show_link_ifindex_{plain,json}(). The XDP link info only
exposes the ifindex.

Below shows an example link dump output, and a cgroup link is included
for comparison, too:

  # bpftool link
  [...]
  10: cgroup  prog 2466
        cgroup_id 1  attach_type cgroup_inet6_post_bind
  [...]
  16: xdp  prog 2477
        ifindex enp5s0(3)
  [...]

Equivalent json output:

  # bpftool link --json
  [...]
  {
    "id": 10,
    "type": "cgroup",
    "prog_id": 2466,
    "cgroup_id": 1,
    "attach_type": "cgroup_inet6_post_bind"
  },
  [...]
  {
    "id": 16,
    "type": "xdp",
    "prog_id": 2477,
    "devname": "enp5s0",
    "ifindex": 3
  }
  [...]

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/r/20230816095651.10014-2-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Add support to dump tcx link information to bpftool. This adds a
common helper show_link_ifindex_{plain,json}() which can be reused
also for other link types. The plain text and json device output is
the same format as in bpftool net dump.

Below shows an example link dump output along with a cgroup link
for comparison:

  # bpftool link
  [...]
  10: cgroup  prog 1977
        cgroup_id 1  attach_type cgroup_inet6_post_bind
  [...]
  13: tcx  prog 2053
        ifindex enp5s0(3)  attach_type tcx_ingress
  14: tcx  prog 2080
        ifindex enp5s0(3)  attach_type tcx_egress
  [...]

Equivalent json output:

  # bpftool link --json
  [...]
  {
    "id": 10,
    "type": "cgroup",
    "prog_id": 1977,
    "cgroup_id": 1,
    "attach_type": "cgroup_inet6_post_bind"
  },
  [...]
  {
    "id": 13,
    "type": "tcx",
    "prog_id": 2053,
    "devname": "enp5s0",
    "ifindex": 3,
    "attach_type": "tcx_ingress"
  },
  {
    "id": 14,
    "type": "tcx",
    "prog_id": 2080,
    "devname": "enp5s0",
    "ifindex": 3,
    "attach_type": "tcx_egress"
  }
  [...]

Suggested-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230816095651.10014-1-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Currently, bpftool perf subcommand has typo with the help message.

    $ tools/bpf/bpftool/bpftool perf help
    Usage: bpftool perf { show | list }
           bpftool perf help }

Since this bpftool perf subcommand help message has the extra bracket,
this commit fix the typo by removing the extra bracket.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/r/20230811121603.17429-1-danieltimlee@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Add support to dump fd-based attach types via bpftool. This includes both
the tc BPF link and attach ops programs. Dumped information contain the
attach location, function entry name, program ID and link ID when applicable.

Example with tc BPF link:

  # ./bpftool net
  xdp:

  tc:
  bond0(4) tcx/ingress cil_from_netdev prog_id 784 link_id 10
  bond0(4) tcx/egress cil_to_netdev prog_id 804 link_id 11

  flow_dissector:

  netfilter:

Example with tc BPF attach ops:

  # ./bpftool net
  xdp:

  tc:
  bond0(4) tcx/ingress cil_from_netdev prog_id 654
  bond0(4) tcx/egress cil_to_netdev prog_id 672

  flow_dissector:

  netfilter:

Currently, permanent flags are not yet supported, so 'unknown' ones are dumped
via NET_DUMP_UINT_ONLY() and once we do have permanent ones, we dump them as
human readable string.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/r/20230719140858.13224-7-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

After using "__fallthrough;" in a switch/case block in bpftool's
btf_dumper.c [0], and then turning it into a comment [1] to prevent a
merge conflict in linux-next when the keyword was changed into just
"fallthrough;" [2], we can now drop the comment and use the new keyword,
no underscores.

Also update the other occurrence of "/* fallthrough */" in bpftool.

[0] commit 9fd496848b1c ("bpftool: Support inline annotations when dumping the CFG of a program")
[1] commit 4b7ef71ac977 ("bpftool: Replace "__fallthrough" by a comment to address merge conflict")
[2] commit f7a858bffcdd ("tools: Rename __fallthrough to fallthrough")

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230712152322.81758-1-quentin@isovalent.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
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>

Add new functions and macros to get perf event names. These names except
the perf_type_name are all copied from
tool/perf/util/{parse-events,evsel}.c, so that in the future we will
have a good chance to use the same code.

Suggested-by: Jiri Olsa <olsajiri@gmail.com>
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/20230709025630.3735-10-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Show the already expose kprobe_multi link info in bpftool. The result as
follows,

$ tools/bpf/bpftool/bpftool link show
91: kprobe_multi  prog 244
        kprobe.multi  func_cnt 7
        addr             func [module]
        ffffffff98c44f20 schedule_timeout_interruptible
        ffffffff98c44f60 schedule_timeout_killable
        ffffffff98c44fa0 schedule_timeout_uninterruptible
        ffffffff98c44fe0 schedule_timeout_idle
        ffffffffc075b8d0 xfs_trans_get_efd [xfs]
        ffffffffc0768a10 xfs_trans_get_buf_map [xfs]
        ffffffffc076c320 xfs_trans_get_dqtrx [xfs]
        pids kprobe_multi(188367)
92: kprobe_multi  prog 244
        kretprobe.multi  func_cnt 7
        addr             func [module]
        ffffffff98c44f20 schedule_timeout_interruptible
        ffffffff98c44f60 schedule_timeout_killable
        ffffffff98c44fa0 schedule_timeout_uninterruptible
        ffffffff98c44fe0 schedule_timeout_idle
        ffffffffc075b8d0 xfs_trans_get_efd [xfs]
        ffffffffc0768a10 xfs_trans_get_buf_map [xfs]
        ffffffffc076c320 xfs_trans_get_dqtrx [xfs]
        pids kprobe_multi(188367)

$ tools/bpf/bpftool/bpftool link show -j
[{"id":91,"type":"kprobe_multi","prog_id":244,"retprobe":false,"func_cnt":7,"funcs":[{"addr":18446744071977586464,"func":"schedule_timeout_interruptible","module":null},{"addr":18446744071977586528,"func":"schedule_timeout_killable","module":null},{"addr":18446744071977586592,"func":"schedule_timeout_uninterruptible","module":null},{"addr":18446744071977586656,"func":"schedule_timeout_idle","module":null},{"addr":18446744072643524816,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072643578384,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072643592992,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":188367,"comm":"kprobe_multi"}]},{"id":92,"type":"kprobe_multi","prog_id":244,"retprobe":true,"func_cnt":7,"funcs":[{"addr":18446744071977586464,"func":"schedule_timeout_interruptible","module":null},{"addr":18446744071977586528,"func":"schedule_timeout_killable","module":null},{"addr":18446744071977586592,"func":"schedule_timeout_uninterruptible","module":null},{"addr":18446744071977586656,"func":"schedule_timeout_idle","module":null},{"addr":18446744072643524816,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072643578384,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072643592992,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":188367,"comm":"kprobe_multi"}]}]

When kptr_restrict is 2, the result is,

$ tools/bpf/bpftool/bpftool link show
91: kprobe_multi  prog 244
        kprobe.multi  func_cnt 7
92: kprobe_multi  prog 244
        kretprobe.multi  func_cnt 7

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/20230709025630.3735-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

If the kernel symbol is in a module, we will dump the module name as
well. The square brackets around the module name are trimmed.

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/20230709025630.3735-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>