bpf: Allow to specify kernel module BTFs when attaching BPF programs

Add ability for user-space programs to specify non-vmlinux BTF when attaching
BTF-powered BPF programs: raw_tp, fentry/fexit/fmod_ret, LSM, etc. For this,
attach_prog_fd (now with the alias name attach_btf_obj_fd) should specify FD
of a module or vmlinux BTF object. For backwards compatibility reasons,
0 denotes vmlinux BTF. Only kernel BTF (vmlinux or module) can be specified.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-11-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
2020-12-03 12:46:30 -08:00
committed by Alexei Starovoitov
parent 22dc4a0f5e
commit 290248a5b7
5 changed files with 69 additions and 33 deletions

View File

@@ -557,7 +557,12 @@ union bpf_attr {
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
__u32 attach_btf_id; /* in-kernel BTF type id to attach to */
__u32 attach_prog_fd; /* 0 to attach to vmlinux */
union {
/* valid prog_fd to attach to bpf prog */
__u32 attach_prog_fd;
/* or valid module BTF object fd or 0 to attach to vmlinux */
__u32 attach_btf_obj_fd;
};
};
struct { /* anonymous struct used by BPF_OBJ_* commands */