[PATCH v4 0/6] enable creating [k,u]probe with perf_event_open

[Song Liu]

Changes PATCH v3 to PATCH v4:
  Remove uapi define MAX_PROBE_FUNC_NAME_LEN, use KSYM_NAME_LEN instead.
  Add flag PERF_PROBE_CONFIG_IS_RETPROBE for config field of [k,u]probe.
  Optimize ifdef's of CONFIG_KPROBE_EVENTS and CONFIG_UPROBE_EVENTS.
  Optimize checks in perf_event_is_tracing().
  Optimize perf_tp_register().

Changes PATCH v2 to PATCH v3:
  Remove fixed type PERF_TYPE_KPROBE and PERF_TYPE_UPROBE, use dynamic
  type instead.
  Update userspace (samples/bpf, bcc) to look up type from sysfs.
  Change License info in test_many_kprobe_user.c as Philippe Ombredanne
  suggested.

Changes PATCH v1 to PATCH v2:
  Split PERF_TYPE_PROBE into PERF_TYPE_KPROBE and PERF_TYPE_UPROBE.
  Split perf_probe into perf_kprobe and perf_uprobe.
  Remove struct probe_desc, use config1 and config2 instead.

Changes RFC v2 to PATCH v1:
  Check type PERF_TYPE_PROBE in perf_event_set_filter().
  Rebase on to tip perf/core.

Changes RFC v1 to RFC v2:
  Fix build issue reported by kbuild test bot by adding ifdef of
  CONFIG_KPROBE_EVENTS, and CONFIG_UPROBE_EVENTS.

RFC v1 cover letter:

This is to follow up the discussion over "new kprobe api" at Linux
Plumbers 2017:

https://www.linuxplumbersconf.org/2017/ocw/proposals/4808

With current kernel, user space tools can only create/destroy [k,u]probes
with a text-based API (kprobe_events and uprobe_events in tracefs). This
approach relies on user space to clean up the [k,u]probe after using them.
However, this is not easy for user space to clean up properly.

To solve this problem, we introduce a file descriptor based API.
Specifically, we extended perf_event_open to create [k,u]probe, and attach
this [k,u]probe to the file descriptor created by perf_event_open. These
[k,u]probe are associated with this file descriptor, so they are not
available in tracefs.

We reuse large portion of existing trace_kprobe and trace_uprobe code.
Currently, the file descriptor API does not support arguments as the
text-based API does. This should not be a problem, as user of the file
decriptor based API read data through other methods (bpf, etc.).

I also include a patch to to bcc, and a patch to man-page perf_even_open.
Please see the list below. A fork of bcc with this patch is also available
on github:

  https://github.com/liu-song-6/bcc/tree/perf_event_open

Thanks,
Song

man-pages patch:
  perf_event_open.2: add type kprobe and uprobe

bcc patch:
  bcc: Try use new API to create [k,u]probe with perf_event_open

kernel patches:

Song Liu (6):
  perf: prepare perf_event.h for new types perf_kprobe and perf_uprobe
  perf: copy new perf_event.h to tools/include/uapi
  perf: implement pmu perf_kprobe
  perf: implement pmu perf_uprobe
  bpf: add option for bpf_load.c to use perf_kprobe
  bpf: add new test test_many_kprobe

 include/linux/trace_events.h          |   8 ++
 include/uapi/linux/perf_event.h       |  14 +++
 kernel/events/core.c                  |  97 +++++++++++++++++-
 kernel/trace/trace_event_perf.c       | 104 +++++++++++++++++++
 kernel/trace/trace_kprobe.c           |  91 +++++++++++++++--
 kernel/trace/trace_probe.h            |  11 ++
 kernel/trace/trace_uprobe.c           |  86 ++++++++++++++--
 samples/bpf/Makefile                  |   3 +
 samples/bpf/bpf_load.c                |  63 ++++++++++--
 samples/bpf/bpf_load.h                |  14 +++
 samples/bpf/test_many_kprobe_user.c   | 186 ++++++++++++++++++++++++++++++++++
 tools/include/uapi/linux/perf_event.h |  14 +++
 12 files changed, 662 insertions(+), 29 deletions(-)
 create mode 100644 samples/bpf/test_many_kprobe_user.c

--
2.9.5