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 v4:
- Remove condition checking in __bpf_prog_{enter,exit)
The major differences from v3:
- rebase v3 to latest tip.
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/
v3: https://lore.kernel.org/bpf/20220407192552.2343076-1-kuifeng@xxxxxx/
v4: https://lore.kernel.org/bpf/20220411173429.4139609-1-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 | 57 +++++++----
kernel/bpf/trampoline.c | 93 +++++++++++-------
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
