[RFC,bpf-next,1/8] bpf: Add struct_ops context information to struct bpf_prog_aux

Commit Message

Juntong Deng Feb. 5, 2025, 7:30 p.m. UTC

This patch adds struct_ops context information to struct bpf_prog_aux.

This context information will be used in the kfunc filter.

Currently the added context information includes struct_ops member
offset and a pointer to struct bpf_struct_ops.

Signed-off-by: Juntong Deng <[e-mail]>
---
 include/linux/bpf.h   | 2 ++
 kernel/bpf/verifier.c | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f3f50e29d639..e06348a59dcf 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1503,6 +1503,7 @@  struct bpf_prog_aux {
 	u32 real_func_cnt; /* includes hidden progs, only used for JIT and freeing progs */
 	u32 func_idx; /* 0 for non-func prog, the index in func array for func prog */
 	u32 attach_btf_id; /* in-kernel BTF type id to attach to */
+	u32 attach_st_ops_member_off;
 	u32 ctx_arg_info_size;
 	u32 max_rdonly_access;
 	u32 max_rdwr_access;
@@ -1547,6 +1548,7 @@  struct bpf_prog_aux {
 #endif
 	struct bpf_ksym ksym;
 	const struct bpf_prog_ops *ops;
+	const struct bpf_struct_ops *st_ops;
 	struct bpf_map **used_maps;
 	struct mutex used_maps_mutex; /* mutex for used_maps and used_map_cnt */
 	struct btf_mod_pair *used_btfs;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9971c03adfd5..2dee3fd190a4 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -22384,7 +22384,7 @@  static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
 	const struct bpf_struct_ops *st_ops;
 	const struct btf_member *member;
 	struct bpf_prog *prog = env->prog;
-	u32 btf_id, member_idx;
+	u32 btf_id, member_idx, member_off;
 	struct btf *btf;
 	const char *mname;
 	int err;
@@ -22435,7 +22435,8 @@  static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
 		return -EINVAL;
 	}
 
-	err = bpf_struct_ops_supported(st_ops, __btf_member_bit_offset(t, member) / 8);
+	member_off = __btf_member_bit_offset(t, member) / 8;
+	err = bpf_struct_ops_supported(st_ops, member_off);
 	if (err) {
 		verbose(env, "attach to unsupported member %s of struct %s\n",
 			mname, st_ops->name);
@@ -22463,6 +22464,9 @@  static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
 	prog->aux->ctx_arg_info_size =
 		st_ops_desc->arg_info[member_idx].cnt;
 
+	prog->aux->st_ops = st_ops;
+	prog->aux->attach_st_ops_member_off = member_off;
+
 	prog->aux->attach_func_proto = func_proto;
 	prog->aux->attach_func_name = mname;
 	env->ops = st_ops->verifier_ops;