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@xxxxxx/
v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@xxxxxx/
v3: https://lore.kernel.org/bpf/20220407192552.2343076-1-kuifeng@xxxxxx/
v4: https://lore.kernel.org/bpf/20220411173429.4139609-1-kuifeng@xxxxxx/
v5: https://lore.kernel.org/bpf/20220412165555.4146407-1-kuifeng@xxxxxx/
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
