xref: /linux/tools/lib/bpf/btf.h (revision 037fc3368be46dc1a2a90f6e50c8cbce49d75fd6)
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 /*
25  * The .BTF.ext ELF section layout defined as
26  *   struct btf_ext_header
27  *   func_info subsection
28  *
29  * The func_info subsection layout:
30  *   record size for struct bpf_func_info in the func_info subsection
31  *   struct btf_sec_func_info for section #1
32  *   a list of bpf_func_info records for section #1
33  *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
34  *     but may not be identical
35  *   struct btf_sec_func_info for section #2
36  *   a list of bpf_func_info records for section #2
37  *   ......
38  *
39  * Note that the bpf_func_info record size in .BTF.ext may not
40  * be the same as the one defined in include/uapi/linux/bpf.h.
41  * The loader should ensure that record_size meets minimum
42  * requirement and pass the record as is to the kernel. The
43  * kernel will handle the func_info properly based on its contents.
44  */
45 struct btf_ext_header {
46 	__u16	magic;
47 	__u8	version;
48 	__u8	flags;
49 	__u32	hdr_len;
50 
51 	/* All offsets are in bytes relative to the end of this header */
52 	__u32	func_info_off;
53 	__u32	func_info_len;
54 	__u32	line_info_off;
55 	__u32	line_info_len;
56 };
57 
58 LIBBPF_API void btf__free(struct btf *btf);
59 LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
60 LIBBPF_API int btf__load(struct btf *btf);
61 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
62 				   const char *type_name);
63 LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
64 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
65 						  __u32 id);
66 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
67 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
68 LIBBPF_API int btf__fd(const struct btf *btf);
69 LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
70 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
71 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
72 LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
73 				    __u32 expected_key_size,
74 				    __u32 expected_value_size,
75 				    __u32 *key_type_id, __u32 *value_type_id);
76 
77 LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
78 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
79 LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext,
80 					     __u32 *size);
81 LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
82 					const struct btf_ext *btf_ext,
83 					const char *sec_name, __u32 insns_cnt,
84 					void **func_info, __u32 *cnt);
85 LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf,
86 					const struct btf_ext *btf_ext,
87 					const char *sec_name, __u32 insns_cnt,
88 					void **line_info, __u32 *cnt);
89 LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
90 LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
91 
92 struct btf_dedup_opts {
93 	unsigned int dedup_table_size;
94 	bool dont_resolve_fwds;
95 };
96 
97 LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
98 			  const struct btf_dedup_opts *opts);
99 
100 #ifdef __cplusplus
101 } /* extern "C" */
102 #endif
103 
104 #endif /* __LIBBPF_BTF_H */
105