[PATCH dwarves v6 0/6] Attach a cookie to a tracing program.

[Kui-Feng Lee <kuifeng@fb.com>]

Allow users to attach a 64-bits cookie to a bpf_link of fentry, fexit,
or fmod_ret.

This patchset includes several major changes.

 - Define struct bpf_tramp_links to replace bpf_tramp_prog.
    struct bpf_tramp_links collects bpf_links of a trampoline

 - Generate a trampoline to call bpf_progs of given bpf_links.

 - Trampolines always set/reset bpf_run_ctx before/after
    calling/leaving a tracing program.

 - Attach a cookie to a bpf_link of fentry/fexit/fmod_ret.  The value
    will be available when running the associated bpf_prog.

The major differences from v5:

 - Fix a bug of refcount of bpf_prog in struct_ops.

 - Don't save/restore rdx anymore, because it is a nonvolatile
   register of the ABI.

 - Move BPF_LINK_CREATE parts to a separated patch (4/6).

 - Fallback to bpf_program__attach_trace() if the value of cookie is
   zero.

v1: https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@fb.com/
v3: https://lore.kernel.org/bpf/20220407192552.2343076-1-kuifeng@fb.com/
v4: https://lore.kernel.org/bpf/20220411173429.4139609-1-kuifeng@fb.com/
v5: https://lore.kernel.org/bpf/20220412165555.4146407-1-kuifeng@fb.com/

Kui-Feng Lee (6):
  bpf, x86: Generate trampolines from bpf_tramp_links
  bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack
  bpf, x86: Attach a cookie to fentry/fexit/fmod_ret.
  bpf: Create fentry/fexit/fmod_ret links through BPF_LINK_CREATE
  libbpf: Assign cookies to links in libbpf.
  selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret.

 arch/x86/net/bpf_jit_comp.c                   | 82 ++++++++++++----
 include/linux/bpf.h                           | 54 +++++++----
 include/linux/bpf_types.h                     |  1 +
 include/uapi/linux/bpf.h                      |  8 ++
 kernel/bpf/bpf_struct_ops.c                   | 69 +++++++++-----
 kernel/bpf/syscall.c                          | 49 ++++++----
 kernel/bpf/trampoline.c                       | 93 ++++++++++++-------
 kernel/trace/bpf_trace.c                      | 17 ++++
 net/bpf/bpf_dummy_struct_ops.c                | 37 +++++++-
 tools/bpf/bpftool/link.c                      |  1 +
 tools/include/uapi/linux/bpf.h                |  8 ++
 tools/lib/bpf/bpf.c                           |  7 ++
 tools/lib/bpf/bpf.h                           |  3 +
 tools/lib/bpf/libbpf.c                        | 38 ++++++++
 tools/lib/bpf/libbpf.h                        | 12 +++
 tools/lib/bpf/libbpf.map                      |  1 +
 .../selftests/bpf/prog_tests/bpf_cookie.c     | 53 +++++++++++
 .../selftests/bpf/progs/test_bpf_cookie.c     | 40 ++++++--
 18 files changed, 449 insertions(+), 124 deletions(-)

-- 
2.30.2