Commit 69ff3047 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

bpf: Add elem_id pointer as argument to __btf_resolve_size 



If the resolved type is array, make btf_resolve_size return also
ID of the elem type. It will be needed in following changes.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-5-jolsa@kernel.org
parent 6298399b

kernel/bpf/btf.c

+7 −3
Original line number Diff line number Diff line
@@ -1079,6 +1079,7 @@ static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env) 
 * *type_size: (x * y * sizeof(u32)).  Hence, *type_size always

 *             corresponds to the return type.

 * *elem_type: u32

 * *elem_id: id of u32

 * *total_nelems: (x * y).  Hence, individual elem size is

 *                (*type_size / *total_nelems)

 *
@@ -1086,15 +1087,16 @@ static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env) 
 * return type: type "struct X"

 * *type_size: sizeof(struct X)

 * *elem_type: same as return type ("struct X")

 * *elem_id: 0

 * *total_nelems: 1

 */

static const struct btf_type *

__btf_resolve_size(const struct btf *btf, const struct btf_type *type,

		   u32 *type_size, const struct btf_type **elem_type,

		   u32 *total_nelems)

		   u32 *elem_id, u32 *total_nelems)

{

	const struct btf_type *array_type = NULL;

	const struct btf_array *array;

	const struct btf_array *array = NULL;

	u32 i, size, nelems = 1;



	for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
@@ -1146,6 +1148,8 @@ __btf_resolve_size(const struct btf *btf, const struct btf_type *type, 
		*total_nelems = nelems;

	if (elem_type)

		*elem_type = type;

	if (elem_id)

		*elem_id = array ? array->type : 0;



	return array_type ? : type;

}
@@ -3984,7 +3988,7 @@ int btf_struct_access(struct bpf_verifier_log *log, 
		mname = __btf_name_by_offset(btf_vmlinux, member->name_off);



		mtype = __btf_resolve_size(btf_vmlinux, mtype, &msize,

					   &elem_type, &total_nelems);

					   &elem_type, NULL, &total_nelems);

		if (IS_ERR(mtype)) {

			bpf_log(log, "field %s doesn't have size\n", mname);

			return -EFAULT;