xref: /openbmc/linux/tools/lib/bpf/btf.h (revision cb1aaebe)
1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /* Copyright (c) 2018 Facebook */
3 
4 #ifndef __LIBBPF_BTF_H
5 #define __LIBBPF_BTF_H
6 
7 #include <linux/types.h>
8 
9 #ifdef __cplusplus
10 extern "C" {
11 #endif
12 
13 #ifndef LIBBPF_API
14 #define LIBBPF_API __attribute__((visibility("default")))
15 #endif
16 
17 #define BTF_ELF_SEC ".BTF"
18 #define BTF_EXT_ELF_SEC ".BTF.ext"
19 
20 struct btf;
21 struct btf_ext;
22 struct btf_type;
23 
24 struct bpf_object;
25 
26 /*
27  * The .BTF.ext ELF section layout defined as
28  *   struct btf_ext_header
29  *   func_info subsection
30  *
31  * The func_info subsection layout:
32  *   record size for struct bpf_func_info in the func_info subsection
33  *   struct btf_sec_func_info for section #1
34  *   a list of bpf_func_info records for section #1
35  *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
36  *     but may not be identical
37  *   struct btf_sec_func_info for section #2
38  *   a list of bpf_func_info records for section #2
39  *   ......
40  *
41  * Note that the bpf_func_info record size in .BTF.ext may not
42  * be the same as the one defined in include/uapi/linux/bpf.h.
43  * The loader should ensure that record_size meets minimum
44  * requirement and pass the record as is to the kernel. The
45  * kernel will handle the func_info properly based on its contents.
46  */
47 struct btf_ext_header {
48 	__u16	magic;
49 	__u8	version;
50 	__u8	flags;
51 	__u32	hdr_len;
52 
53 	/* All offsets are in bytes relative to the end of this header */
54 	__u32	func_info_off;
55 	__u32	func_info_len;
56 	__u32	line_info_off;
57 	__u32	line_info_len;
58 };
59 
60 LIBBPF_API void btf__free(struct btf *btf);
61 LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
62 LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
63 LIBBPF_API int btf__load(struct btf *btf);
64 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
65 				   const char *type_name);
66 LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
67 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
68 						  __u32 id);
69 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
70 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
71 LIBBPF_API int btf__fd(const struct btf *btf);
72 LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
73 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
74 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
75 LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
76 				    __u32 expected_key_size,
77 				    __u32 expected_value_size,
78 				    __u32 *key_type_id, __u32 *value_type_id);
79 
80 LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
81 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
82 LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext,
83 					     __u32 *size);
84 LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
85 					const struct btf_ext *btf_ext,
86 					const char *sec_name, __u32 insns_cnt,
87 					void **func_info, __u32 *cnt);
88 LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf,
89 					const struct btf_ext *btf_ext,
90 					const char *sec_name, __u32 insns_cnt,
91 					void **line_info, __u32 *cnt);
92 LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
93 LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
94 
95 struct btf_dedup_opts {
96 	unsigned int dedup_table_size;
97 	bool dont_resolve_fwds;
98 };
99 
100 LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
101 			  const struct btf_dedup_opts *opts);
102 
103 #ifdef __cplusplus
104 } /* extern "C" */
105 #endif
106 
107 #endif /* __LIBBPF_BTF_H */
108