Commit e87c6bc3852b ("bpf: permit multiple bpf attachments
for a single perf event") added support to attach multiple
bpf programs to a single perf event. Given a perf event
(kprobe, uprobe, or kernel tracepoint), the perf ioctl interface
is used to query bpf programs attached to the same trace event.
There already exists a BPF_PROG_QUERY command for introspection
currently used by cgroup+bpf. We did have an implementation for
querying tracepoint+bpf through the same interface. However, it
looks cleaner to use ioctl() style of api here, since attaching
bpf prog to tracepoint/kuprobe is also done via ioctl.
Patch #1 had the core implementation and patch #2 added
a test case in tools bpf selftests suite.
Changelogs:
v3 -> v4:
- Fix a compilation error with newer gcc like 6.3.1 while
old gcc 4.8.5 is okay. I was using >ids to represent
the address to the ids array to make it explicit that the
address is passed, and this syntax is rightly rejected
by gcc 6.3.1.
v2 -> v3:
- Change uapi structure perf_event_query_bpf to be more
clearer based on Peter's suggestion, and adjust
other codes accordingly.
v1 -> v2:
- Rebase on top of net-next.
- Use existing bpf_prog_array_length function instead of
implementing the same functionality in function
bpf_prog_array_copy_info.
Yonghong Song (2):
bpf/tracing: allow user space to query prog array on the same tp
bpf/tracing: add a bpf test for new ioctl query interface
include/linux/bpf.h | 4 +
include/uapi/linux/perf_event.h | 22 +
kernel/bpf/core.c | 21
kernel/events/core.c | 3 +
kernel/trace/bpf_trace.c | 23 +
tools/include/uapi/linux/perf_event.h | 22 +
tools/testing/selftests/bpf/Makefile | 2 +-
tools/testing/selftests/bpf/test_progs.c | 134 ++
tools/testing/selftests/bpf/test_tracepoint.c | 26 +
9 files changed, 256 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/test_tracepoint.c
--
2.9.5
