[PATCH v11 perf, bpf-next 0/9] reveal invisible bpf programs

[Song Liu]

This set catches symbol for all bpf programs loaded/unloaded
before/during/after perf-record run PERF_RECORD_KSYMBOL and
PERF_RECORD_BPF_EVENT.

PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT includes key information
of a bpf program load and unload. They are sent through perf ringbuffer,
and stored in perf.data. PERF_RECORD_KSYMBOL includes basic information
for simple profiling. It is ON by default. PERF_RECORD_BPF_EVENT is
used to gather more information of the bpf program. It is necessary for
perf-annotate of bpf programs.

Before this patch, perf-report will not be able to recover symbols of
bpf programs once the programs are unloaded.

This is to follow up Alexei's early effort [2] to show bpf programs via
mmap events.

Thanks,
Song

Changes v10 -> v11:
1. Removed perf_ksymbol_get_name_f;
2. Added BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)) to perf_event_bpf_event.

Changes v9 -> v10:
1. Added pr_debug() to show issue while synthesize BPF events;
2. Fixed code style to match existing code.

Changes v8 -> PATCH v9:
1. Per suggestion by Arnaldo, recorded checks in perf_missing_features.

Changes v7 -> PATCH v8:

1. Fixed perf dump_stack to use stdout instead of stderr;
2. Added module name [bpf] to /proc/kallsyms (9/9);
3. Do not show warning "Couldn't synthesize bpf events." when the kernel
   does not support proper sys_bpf call;
4. Added Arnaldo's patch that synthesizes BPF events in perf-top.

Changes v6 -> PATCH v7:
1. Split "[3/7] introduce PERF_RECORD_BPF_EVENT" into two commits:
     [3/8] introduce PERF_RECORD_BPF_EVENT
     [5/8] emit PERF_RECORD_KSYMBOL for BPF program load/unload

Changes v5 -> PATCH v6:
1. Reduce len in PERF_RECORD_KSYMBOL from u64 to u32. Use the 32 free bits
   for ksym_type (u16) and flags (u16).

Changes v4 -> PATCH v5:
1. Fixed build error reported by kbuild test bot.

Changes v3 -> PATCH v4:
1. Split information about bpf program  into PERF_RECORD_KSYMBOL (with
   name, addr, len); and PERF_RECORD_BPF_EVENT PERF_RECORD_BPF_EVENT
   (with id, tag);
2. Split the implementation in kernel and user space.

Changes v2 -> PATCH v3:
1. Rebase on bpf-next tree, and on top of BPF sub program tag patches [1]
   for latest information in bpf_prog_info.
2. Complete handling and synthesizing PERF_RECORD_BPF_EVENT in perf.

Changes v1 -> PATCH v2:
1. Only 3 of the 5 patches in v1, to focus on ABI first;
2. Generate PERF_RECORD_BPF_EVENT per bpf sub program instead of per prog;
3. Modify PERF_RECORD_BPF_EVENT with more details (addr, len, name),
   so that it can be used for basic profiling without calling sys_bpf.

Changes RFC -> PATCH v1:
1. In perf-record, poll vip events in a separate thread;
2. Add tag to bpf prog name;
3. Small refactorings.

[1] https://patchwork.ozlabs.org/project/netdev/list/?series=81037
[2] https://www.spinics.net/lists/netdev/msg524232.html

Arnaldo Carvalho de Melo (1):
  perf top: Synthesize BPF events for pre-existing loaded BPF programs

Song Liu (8):
  perf, bpf: Introduce PERF_RECORD_KSYMBOL
  sync tools/include/uapi/linux/perf_event.h
  perf, bpf: introduce PERF_RECORD_BPF_EVENT
  sync tools/include/uapi/linux/perf_event.h
  perf util: handle PERF_RECORD_KSYMBOL
  perf util: handle PERF_RECORD_BPF_EVENT
  perf tools: synthesize PERF_RECORD_* for loaded BPF programs
  bpf: add module name [bpf] to ksymbols for bpf programs

 include/linux/filter.h                |   7 +
 include/linux/perf_event.h            |  14 ++
 include/uapi/linux/perf_event.h       |  53 +++++-
 kernel/bpf/core.c                     |   2 +-
 kernel/bpf/syscall.c                  |   2 +
 kernel/events/core.c                  | 213 ++++++++++++++++++++-
 kernel/kallsyms.c                     |   2 +-
 tools/include/uapi/linux/perf_event.h |  53 +++++-
 tools/perf/builtin-record.c           |   7 +
 tools/perf/builtin-top.c              |   7 +
 tools/perf/perf.h                     |   1 +
 tools/perf/util/Build                 |   2 +
 tools/perf/util/bpf-event.c           | 256 ++++++++++++++++++++++++++
 tools/perf/util/bpf-event.h           |  16 ++
 tools/perf/util/event.c               |  41 +++++
 tools/perf/util/event.h               |  36 ++++
 tools/perf/util/evsel.c               |  19 +-
 tools/perf/util/evsel.h               |   2 +
 tools/perf/util/machine.c             |  58 ++++++
 tools/perf/util/machine.h             |   3 +
 tools/perf/util/session.c             |   8 +
 tools/perf/util/tool.h                |   5 +-
 22 files changed, 800 insertions(+), 7 deletions(-)
 create mode 100644 tools/perf/util/bpf-event.c
 create mode 100644 tools/perf/util/bpf-event.h

--
2.17.1