libbpf: implement BPF CO-RE offset relocation algorithm

This patch implements the core logic for BPF CO-RE offsets relocations.
Every instruction that needs to be relocated has corresponding
bpf_offset_reloc as part of BTF.ext. Relocations are performed by trying
to match recorded "local" relocation spec against potentially many
compatible "target" types, creating corresponding spec. Details of the
algorithm are noted in corresponding comments in the code.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko 2019-08-07 14:39:51 -07:00 committed by Alexei Starovoitov
parent 4cedc0dad9
commit ddc7c30426
2 changed files with 864 additions and 18 deletions

View file

@ -92,6 +92,7 @@ LIBBPF_API void bpf_object__close(struct bpf_object *object);
struct bpf_object_load_attr {
struct bpf_object *obj;
int log_level;
const char *target_btf_path;
};
/* Load/unload object into/from kernel */