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 v2: - Move the allocations of run_ctx (struct bpf_tramp_run_ctx) out of invoke_bpf_prog(). - Move hlist_node out of bpf_link and introduce struct bpf_tramp_link to own hlist_node. - Store cookies at struct bpf_tracing_link. - Use SIB byte to reduce the number of instructions to set cookie values. (Use RSP directly) v1: https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@xxxxxx/ v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@xxxxxx/ Kui-Feng Lee (5): 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. lib/bpf: 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 | 98 +++++++++++++++---- include/linux/bpf.h | 56 ++++++++--- include/linux/bpf_types.h | 1 + include/uapi/linux/bpf.h | 9 ++ kernel/bpf/bpf_struct_ops.c | 69 ++++++++----- kernel/bpf/syscall.c | 54 ++++++---- kernel/bpf/trampoline.c | 96 +++++++++++------- kernel/trace/bpf_trace.c | 17 ++++ net/bpf/bpf_dummy_struct_ops.c | 35 ++++++- 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 | 33 +++++++ tools/lib/bpf/libbpf.h | 12 +++ tools/lib/bpf/libbpf.map | 1 + .../selftests/bpf/prog_tests/bpf_cookie.c | 52 ++++++++++ .../selftests/bpf/progs/test_bpf_cookie.c | 24 +++++ 18 files changed, 459 insertions(+), 117 deletions(-) -- 2.30.2
