ftrace: Event probe updates

This series adds some features/tests to event probe, which includes
- Add event probe syntax error logs on <tracefs>/error_log file.
- Add 'if' filter to the event probe.
- Add a syntax error test case for event probe.

'if' filter is a new feature, which allows us to define new event based on the condition. There are some events which include both start and end events by one event type. e.g. CPU idle (power/cpu_idle) event is called at the CPU idle start with "state=C-state ID" and at the end with "state=(u32)-1". In that case, it is useful if we can define 2 new event probes on it for the start and the end besed on the state value. Or, we can classify events based on running CPU, etc.

Thanks,

---

Masami Hiramatsu (Google) (3):
tracing/eprobe: Show syntax error logs in error_log file tracing/eprobe: Add eprobe filter support selftests/ftrace: Add eprobe syntax error testcase

 kernel/trace/trace_eprobe.c                        |  115 ++++++++++++++++++--
 kernel/trace/trace_probe.h                         |    6 +
 .../test.d/dynevent/eprobes_syntax_errors.tc       |   27 +++++
 3 files changed, 137 insertions(+), 11 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/eprobes_syntax_errors.tc

--
Masami Hiramatsu (Google) <[email protected]>