xref: /openbmc/linux/tools/lib/bpf/btf.h (revision 5e012745)
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 <stdarg.h>
8 #include <linux/types.h>
9 
10 #ifdef __cplusplus
11 extern "C" {
12 #endif
13 
14 #ifndef LIBBPF_API
15 #define LIBBPF_API __attribute__((visibility("default")))
16 #endif
17 
18 #define BTF_ELF_SEC ".BTF"
19 #define BTF_EXT_ELF_SEC ".BTF.ext"
20 #define MAPS_ELF_SEC ".maps"
21 
22 struct btf;
23 struct btf_ext;
24 struct btf_type;
25 
26 struct bpf_object;
27 
28 /*
29  * The .BTF.ext ELF section layout defined as
30  *   struct btf_ext_header
31  *   func_info subsection
32  *
33  * The func_info subsection layout:
34  *   record size for struct bpf_func_info in the func_info subsection
35  *   struct btf_sec_func_info for section #1
36  *   a list of bpf_func_info records for section #1
37  *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
38  *     but may not be identical
39  *   struct btf_sec_func_info for section #2
40  *   a list of bpf_func_info records for section #2
41  *   ......
42  *
43  * Note that the bpf_func_info record size in .BTF.ext may not
44  * be the same as the one defined in include/uapi/linux/bpf.h.
45  * The loader should ensure that record_size meets minimum
46  * requirement and pass the record as is to the kernel. The
47  * kernel will handle the func_info properly based on its contents.
48  */
49 struct btf_ext_header {
50 	__u16	magic;
51 	__u8	version;
52 	__u8	flags;
53 	__u32	hdr_len;
54 
55 	/* All offsets are in bytes relative to the end of this header */
56 	__u32	func_info_off;
57 	__u32	func_info_len;
58 	__u32	line_info_off;
59 	__u32	line_info_len;
60 };
61 
62 LIBBPF_API void btf__free(struct btf *btf);
63 LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
64 LIBBPF_API struct btf *btf__parse_elf(const char *path,
65 				      struct btf_ext **btf_ext);
66 LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
67 LIBBPF_API int btf__load(struct btf *btf);
68 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
69 				   const char *type_name);
70 LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
71 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
72 						  __u32 id);
73 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
74 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
75 LIBBPF_API int btf__fd(const struct btf *btf);
76 LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
77 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
78 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
79 LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
80 				    __u32 expected_key_size,
81 				    __u32 expected_value_size,
82 				    __u32 *key_type_id, __u32 *value_type_id);
83 
84 LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
85 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
86 LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext,
87 					     __u32 *size);
88 LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
89 					const struct btf_ext *btf_ext,
90 					const char *sec_name, __u32 insns_cnt,
91 					void **func_info, __u32 *cnt);
92 LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf,
93 					const struct btf_ext *btf_ext,
94 					const char *sec_name, __u32 insns_cnt,
95 					void **line_info, __u32 *cnt);
96 LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
97 LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
98 
99 struct btf_dedup_opts {
100 	unsigned int dedup_table_size;
101 	bool dont_resolve_fwds;
102 };
103 
104 LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
105 			  const struct btf_dedup_opts *opts);
106 
107 struct btf_dump;
108 
109 struct btf_dump_opts {
110 	void *ctx;
111 };
112 
113 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
114 
115 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
116 					  const struct btf_ext *btf_ext,
117 					  const struct btf_dump_opts *opts,
118 					  btf_dump_printf_fn_t printf_fn);
119 LIBBPF_API void btf_dump__free(struct btf_dump *d);
120 
121 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
122 
123 #ifdef __cplusplus
124 } /* extern "C" */
125 #endif
126 
127 #endif /* __LIBBPF_BTF_H */
128