From: Alexei Starovoitov <ast@xxxxxxxxxx>
v3->v4:
. complete refactor of find candidates logic.
Now it has small permanent cache.
I haven't completed testing of all corner cases,
but the patches are clean enough for review.
. Fix a bug in gen_loader related to attach_kind.
. Fix BTF log size limit.
. More tests.
v2->v3:
. addressed Andrii's feedback in every patch.
New field in union bpf_attr changed from "core_relo" to "core_relos".
. added one more test and checkpatch.pl-ed the set.
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 (16):
libbpf: Replace btf__type_by_id() with 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: Adjust BTF log size limit.
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.
libbpf: Clean gen_loader's attach kind.
selftests/bpf: Add lskel version of kfunc test.
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.
selftests/bpf: Revert CO-RE removal in test_ksyms_weak.
selftests/bpf: Add CO-RE relocations to verifier scale test.
include/linux/bpf.h | 8 +
include/linux/btf.h | 89 +++++-
include/uapi/linux/bpf.h | 78 ++++-
kernel/bpf/Makefile | 4 +
kernel/bpf/bpf_struct_ops.c | 6 +-
kernel/bpf/btf.c | 300 +++++++++++++++++-
kernel/bpf/syscall.c | 2 +-
kernel/bpf/verifier.c | 76 +++++
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 | 72 ++++-
tools/lib/bpf/libbpf.c | 116 +++++--
tools/lib/bpf/libbpf_internal.h | 2 +-
tools/lib/bpf/relo_core.c | 179 +++++++----
tools/lib/bpf/relo_core.h | 73 +----
tools/testing/selftests/bpf/Makefile | 5 +-
.../selftests/bpf/prog_tests/core_kern.c | 14 +
.../selftests/bpf/prog_tests/kfunc_call.c | 24 ++
.../selftests/bpf/prog_tests/map_ptr.c | 16 +-
tools/testing/selftests/bpf/progs/core_kern.c | 87 +++++
.../selftests/bpf/progs/map_ptr_kern.c | 16 +-
.../selftests/bpf/progs/test_ksyms_weak.c | 2 +-
.../selftests/bpf/progs/test_verif_scale2.c | 4 +-
25 files changed, 1050 insertions(+), 213 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
