From: Alexei Starovoitov <ast@xxxxxxxxxx>
v1->v2:
. Refactor uapi to pass 'struct bpf_core_relo' from LLVM into libbpf and further
into the kernel instead of bpf_core_apply_relo() bpf helper. Because of this
change the CO-RE algorithm has an ability to log error and debug events through
the standard bpf verifer log mechanism which was not possible with helper
approach.
. #define RELO_CORE macro was removed and replaced with btf_member_bit_offset() patch.
This set introduces CO-RE support in the kernel.
There are several reasons to add such support:
1. It's a step toward signed BPF programs.
2. It allows golang like languages that struggle to adopt libbpf
to take advantage of CO-RE powers.
3. Currently the field accessed by 'ldx [R1 + 10]' insn is recognized
by the verifier purely based on +10 offset. If R1 points to a union
the verifier picks one of the fields at this offset.
With CO-RE the kernel can disambiguate the field access.
Alexei Starovoitov (12):
libbpf: s/btf__type_by_id/btf_type_by_id/.
bpf: Rename btf_member accessors.
bpf: Prepare relo_core.c for kernel duty.
bpf: Define enum bpf_core_relo_kind as uapi.
bpf: Pass a set of bpf_core_relo-s to prog_load command.
bpf: Add bpf_core_add_cands() and wire it into
bpf_core_apply_relo_insn().
libbpf: Use CO-RE in the kernel in light skeleton.
libbpf: Support init of inner maps in light skeleton.
selftests/bpf: Convert kfunc test with CO-RE to lskel.
selftests/bpf: Improve inner_map test coverage.
selftests/bpf: Convert map_ptr_kern test to use light skeleton.
selftests/bpf: Additional test for CO-RE in the kernel.
include/linux/bpf.h | 3 +
include/linux/btf.h | 90 ++++++++-
include/uapi/linux/bpf.h | 78 +++++++-
kernel/bpf/Makefile | 4 +
kernel/bpf/bpf_struct_ops.c | 6 +-
kernel/bpf/btf.c | 187 +++++++++++++++++-
kernel/bpf/syscall.c | 2 +-
kernel/bpf/verifier.c | 71 +++++++
net/ipv4/bpf_tcp_ca.c | 6 +-
tools/include/uapi/linux/bpf.h | 78 +++++++-
tools/lib/bpf/bpf_gen_internal.h | 4 +
tools/lib/bpf/btf.c | 2 +-
tools/lib/bpf/gen_loader.c | 68 ++++++-
tools/lib/bpf/libbpf.c | 112 ++++++++---
tools/lib/bpf/libbpf_internal.h | 2 +-
tools/lib/bpf/relo_core.c | 171 ++++++++++------
tools/lib/bpf/relo_core.h | 71 -------
tools/testing/selftests/bpf/Makefile | 3 +-
.../selftests/bpf/prog_tests/core_kern.c | 21 ++
.../selftests/bpf/prog_tests/kfunc_call.c | 10 +-
.../selftests/bpf/prog_tests/map_ptr.c | 16 +-
tools/testing/selftests/bpf/progs/core_kern.c | 60 ++++++
.../selftests/bpf/progs/map_ptr_kern.c | 16 +-
23 files changed, 877 insertions(+), 204 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/core_kern.c
create mode 100644 tools/testing/selftests/bpf/progs/core_kern.c
--
2.30.2
