Implement libbpf support for performing CO-RE relocations against types in kernel module BTFs, in addition to existing vmlinux BTF support. This is a first step towards fully supporting kernel module BTFs. Subsequent patch sets will expand kernel and libbpf sides to allow using other BTF-powered capabilities (fentry/fexit, struct_ops, ksym externs, etc). For CO-RE relocations support, though, no extra kernel changes are necessary. This patch set also sets up a convenient and fully-controlled custom kernel module (called "bpf_testmod"), that is a predictable playground for all the BPF selftests, that rely on module BTFs. v2->v3: - fix subtle uninitialized variable use in BTF ID iteration code; v1->v2: - module_put() inside preempt_disable() region (Alexei); - bpf_sidecar -> bpf_testmod rename (Alexei); - test_progs more relaxed handling of bpf_testmod; - test_progs marks skipped sub-tests properly as SKIP now. Andrii Nakryiko (7): bpf: fix bpf_put_raw_tracepoint()'s use of __module_address() libbpf: add internal helper to load BTF data by FD libbpf: refactor CO-RE relocs to not assume a single BTF object libbpf: add kernel module BTF support for CO-RE relocations selftests/bpf: add bpf_testmod kernel module for testing selftests/bpf: add support for marking sub-tests as skipped selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF kernel/trace/bpf_trace.c | 8 +- tools/lib/bpf/btf.c | 61 ++-- tools/lib/bpf/libbpf.c | 345 ++++++++++++++---- tools/lib/bpf/libbpf_internal.h | 1 + tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 12 +- .../selftests/bpf/bpf_testmod/.gitignore | 6 + .../selftests/bpf/bpf_testmod/Makefile | 20 + .../bpf/bpf_testmod/bpf_testmod-events.h | 36 ++ .../selftests/bpf/bpf_testmod/bpf_testmod.c | 51 +++ .../selftests/bpf/bpf_testmod/bpf_testmod.h | 14 + .../selftests/bpf/prog_tests/core_reloc.c | 79 +++- .../selftests/bpf/progs/core_reloc_types.h | 17 + .../bpf/progs/test_core_reloc_module.c | 66 ++++ tools/testing/selftests/bpf/test_progs.c | 65 +++- tools/testing/selftests/bpf/test_progs.h | 1 + 16 files changed, 661 insertions(+), 122 deletions(-) create mode 100644 tools/testing/selftests/bpf/bpf_testmod/.gitignore create mode 100644 tools/testing/selftests/bpf/bpf_testmod/Makefile create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_module.c -- 2.24.1
