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_sidecar"), that is a predictable playground for all the BPF selftests, that rely on module BTFs. Andrii Nakryiko (6): 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_sidecar kernel module for testing selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF kernel/trace/bpf_trace.c | 6 +- tools/lib/bpf/btf.c | 61 +-- tools/lib/bpf/libbpf.c | 352 ++++++++++++++---- tools/lib/bpf/libbpf_internal.h | 1 + tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 12 +- .../selftests/bpf/bpf_sidecar/.gitignore | 6 + .../selftests/bpf/bpf_sidecar/Makefile | 20 + .../bpf/bpf_sidecar/bpf_sidecar-events.h | 36 ++ .../selftests/bpf/bpf_sidecar/bpf_sidecar.c | 51 +++ .../selftests/bpf/bpf_sidecar/bpf_sidecar.h | 14 + .../selftests/bpf/prog_tests/core_reloc.c | 72 +++- .../selftests/bpf/progs/core_reloc_types.h | 17 + .../bpf/progs/test_core_reloc_module.c | 66 ++++ tools/testing/selftests/bpf/test_progs.c | 52 +++ 15 files changed, 647 insertions(+), 120 deletions(-) create mode 100644 tools/testing/selftests/bpf/bpf_sidecar/.gitignore create mode 100644 tools/testing/selftests/bpf/bpf_sidecar/Makefile create mode 100644 tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar-events.h create mode 100644 tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.c create mode 100644 tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.h create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_module.c -- 2.24.1
