Hi,
Here is the 6th version of series to introduce more typecast features
to probe events. The previous version is here:
In this version, I fixed some issues found by Sashiko reviews (again),
drop the first bugfix which is merged to probes/core, add new fetcharg
dump patch[1/8] and make typecast always nested[3/8]. This version also
allows all probe events to use $current.
Steve introduced BTF typecast feature for eprobe[1].
This series extends it and add more options:
1. Expanding BTF typecast to kprobe and fprobe.
(currently only function entry/exit)
2. Introduce container_of like typecast. This adds a "assigned
member" option to the typecast.
(STRUCT,MEMBER)VAR->ANOTHER_MEMBER
This casts VAR to STRUCT type but the VAR is as the address
of STRUCT.MEMBER. In C, it is:
container_of(VAR, STRUCT, MEMBER)->ANOTHER_MEMBER
3. Support nested typecast, e.g.
(STRUCT)((STRUCT2)VAR->MEMBER2)->MEMBER
the nest level must be smaller than 3.
4. Add $current variable to point "current" task_struct.
This is useful with typecast, e.g.
(task_struct)$current->pid
5. per-cpu dereference support.
Intrdouce this_cpu_read(VAR) and this_cpu_ptr(VAR) to
access per-cpu data on the current CPU (accessing other CPU
data is not stable, because it can be changed.)
You can access the member of per-cpu data structure using
typecast like:
(STRUCT)this_cpu_ptr(VAR)->MEMBER
And added fetcharg dump feature (for debug) and updated test scripts
to test part of them.
Thanks,
---
base-id: cfae4cb90fc8113d52fea1f0a62cd6a36d9df149
Masami Hiramatsu (Google) (8):
tracing/probes: Support dumping fetcharg program for debugging dynamic
events
tracing/probes: Support typecast for various probe events
tracing/probes: Support nested typecast
tracing/probes: Type casting always involves nested calls
tracing/probes: Support field specifier option for typecast
tracing/probes: Add $current variable support
tracing/probes: Add this_cpu_read() and this_cpu_ptr() dereference method
to fetcharg
tracing/probes: Add a new testcase for BTF typecasts
Documentation/trace/eprobetrace.rst | 9
Documentation/trace/fprobetrace.rst | 10
Documentation/trace/kprobetrace.rst | 11
kernel/trace/Kconfig | 11
kernel/trace/trace.c | 8
kernel/trace/trace_eprobe.c | 2
kernel/trace/trace_fprobe.c | 2
kernel/trace/trace_kprobe.c | 2
kernel/trace/trace_probe.c | 571 ++++++++++++++++----
kernel/trace/trace_probe.h | 95 ++-
kernel/trace/trace_probe_tmpl.h | 25 +
kernel/trace/trace_uprobe.c | 3
samples/trace_events/trace-events-sample.c | 40 +
samples/trace_events/trace-events-sample.h | 34 +
.../ftrace/test.d/dynevent/btf_probe_event.tc | 51 ++
.../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 11
.../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 11
.../ftrace/test.d/kprobe/uprobe_syntax_errors.tc | 5
18 files changed, 747 insertions(+), 154 deletions(-)
create mode 100644
tools/testing/selftests/ftrace/test.d/dynevent/btf_probe_event.tc
--
Masami Hiramatsu (Google) <[email protected]>
