[PATCHv3,bpf-next,0/7] bpf, x86: Add bpf_get_func_ip helper

Message

Jiri Olsa July 7, 2021, 9:47 p.m. UTC

hi,
adding bpf_get_func_ip helper that returns IP address of the
caller function for trampoline and krobe programs.

There're 2 specific implementation of the bpf_get_func_ip
helper, one for trampoline progs and one for kprobe/kretprobe
progs.

The trampoline helper call is replaced/inlined by verifier
with simple move instruction. The kprobe/kretprobe is actual
helper call that returns prepared caller address.

Also available at:
  https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  bpf/get_func_ip

v3 changes:
  - resend with Masami in cc and v3 in each patch subject

v2 changes:
  - use kprobe_running to get kprobe instead of cpu var [Masami]
  - added support to add kprobe on function+offset
    and test for that [Alan]

thanks,
jirka


---
Alan Maguire (1):
      libbpf: allow specification of "kprobe/function+offset"

Jiri Olsa (6):
      bpf, x86: Store caller's ip in trampoline stack
      bpf: Enable BPF_TRAMP_F_IP_ARG for trampolines with call_get_func_ip
      bpf: Add bpf_get_func_ip helper for tracing programs
      bpf: Add bpf_get_func_ip helper for kprobe programs
      selftests/bpf: Add test for bpf_get_func_ip helper
      selftests/bpf: Add test for bpf_get_func_ip in kprobe+offset probe

 arch/x86/net/bpf_jit_comp.c                               | 19 +++++++++++++++++++
 include/linux/bpf.h                                       |  5 +++++
 include/linux/filter.h                                    |  3 ++-
 include/uapi/linux/bpf.h                                  |  7 +++++++
 kernel/bpf/trampoline.c                                   | 12 +++++++++---
 kernel/bpf/verifier.c                                     | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/trace/bpf_trace.c                                  | 32 ++++++++++++++++++++++++++++++++
 tools/include/uapi/linux/bpf.h                            |  7 +++++++
 tools/lib/bpf/libbpf.c                                    | 20 +++++++++++++++++---
 tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/get_func_ip_test.c      | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 11 files changed, 270 insertions(+), 7 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
 create mode 100644 tools/testing/selftests/bpf/progs/get_func_ip_test.c