1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 3 /* 4 * Internal libbpf helpers. 5 * 6 * Copyright (c) 2019 Facebook 7 */ 8 9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H 10 #define __LIBBPF_LIBBPF_INTERNAL_H 11 12 #include "libbpf.h" 13 14 #define BTF_INFO_ENC(kind, kind_flag, vlen) \ 15 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) 16 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) 17 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ 18 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) 19 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ 20 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ 21 BTF_INT_ENC(encoding, bits_offset, bits) 22 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) 23 #define BTF_PARAM_ENC(name, type) (name), (type) 24 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) 25 26 #ifndef min 27 # define min(x, y) ((x) < (y) ? (x) : (y)) 28 #endif 29 #ifndef max 30 # define max(x, y) ((x) < (y) ? (y) : (x)) 31 #endif 32 #ifndef offsetofend 33 # define offsetofend(TYPE, FIELD) \ 34 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 35 #endif 36 37 /* Symbol versioning is different between static and shared library. 38 * Properly versioned symbols are needed for shared library, but 39 * only the symbol of the new version is needed for static library. 40 */ 41 #ifdef SHARED 42 # define COMPAT_VERSION(internal_name, api_name, version) \ 43 asm(".symver " #internal_name "," #api_name "@" #version); 44 # define DEFAULT_VERSION(internal_name, api_name, version) \ 45 asm(".symver " #internal_name "," #api_name "@@" #version); 46 #else 47 # define COMPAT_VERSION(internal_name, api_name, version) 48 # define DEFAULT_VERSION(internal_name, api_name, version) \ 49 extern typeof(internal_name) api_name \ 50 __attribute__((alias(#internal_name))); 51 #endif 52 53 extern void libbpf_print(enum libbpf_print_level level, 54 const char *format, ...) 55 __attribute__((format(printf, 2, 3))); 56 57 #define __pr(level, fmt, ...) \ 58 do { \ 59 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 60 } while (0) 61 62 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 63 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 64 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 65 66 static inline bool libbpf_validate_opts(const char *opts, 67 size_t opts_sz, size_t user_sz, 68 const char *type_name) 69 { 70 if (user_sz < sizeof(size_t)) { 71 pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 72 return false; 73 } 74 if (user_sz > opts_sz) { 75 size_t i; 76 77 for (i = opts_sz; i < user_sz; i++) { 78 if (opts[i]) { 79 pr_warn("%s has non-zero extra bytes", 80 type_name); 81 return false; 82 } 83 } 84 } 85 return true; 86 } 87 88 #define OPTS_VALID(opts, type) \ 89 (!(opts) || libbpf_validate_opts((const char *)opts, \ 90 offsetofend(struct type, \ 91 type##__last_field), \ 92 (opts)->sz, #type)) 93 #define OPTS_HAS(opts, field) \ 94 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 95 #define OPTS_GET(opts, field, fallback_value) \ 96 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 97 98 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 99 const char *str_sec, size_t str_len); 100 101 struct btf_ext_info { 102 /* 103 * info points to the individual info section (e.g. func_info and 104 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 105 */ 106 void *info; 107 __u32 rec_size; 108 __u32 len; 109 }; 110 111 #define for_each_btf_ext_sec(seg, sec) \ 112 for (sec = (seg)->info; \ 113 (void *)sec < (seg)->info + (seg)->len; \ 114 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 115 (seg)->rec_size * sec->num_info) 116 117 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 118 for (i = 0, rec = (void *)&(sec)->data; \ 119 i < (sec)->num_info; \ 120 i++, rec = (void *)rec + (seg)->rec_size) 121 122 struct btf_ext { 123 union { 124 struct btf_ext_header *hdr; 125 void *data; 126 }; 127 struct btf_ext_info func_info; 128 struct btf_ext_info line_info; 129 struct btf_ext_info field_reloc_info; 130 __u32 data_size; 131 }; 132 133 struct btf_ext_info_sec { 134 __u32 sec_name_off; 135 __u32 num_info; 136 /* Followed by num_info * record_size number of bytes */ 137 __u8 data[0]; 138 }; 139 140 /* The minimum bpf_func_info checked by the loader */ 141 struct bpf_func_info_min { 142 __u32 insn_off; 143 __u32 type_id; 144 }; 145 146 /* The minimum bpf_line_info checked by the loader */ 147 struct bpf_line_info_min { 148 __u32 insn_off; 149 __u32 file_name_off; 150 __u32 line_off; 151 __u32 line_col; 152 }; 153 154 /* bpf_field_info_kind encodes which aspect of captured field has to be 155 * adjusted by relocations. Currently supported values are: 156 * - BPF_FIELD_BYTE_OFFSET: field offset (in bytes); 157 * - BPF_FIELD_EXISTS: field existence (1, if field exists; 0, otherwise); 158 */ 159 enum bpf_field_info_kind { 160 BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ 161 BPF_FIELD_BYTE_SIZE = 1, 162 BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ 163 BPF_FIELD_SIGNED = 3, 164 BPF_FIELD_LSHIFT_U64 = 4, 165 BPF_FIELD_RSHIFT_U64 = 5, 166 }; 167 168 /* The minimum bpf_field_reloc checked by the loader 169 * 170 * Field relocation captures the following data: 171 * - insn_off - instruction offset (in bytes) within a BPF program that needs 172 * its insn->imm field to be relocated with actual field info; 173 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable 174 * field; 175 * - access_str_off - offset into corresponding .BTF string section. String 176 * itself encodes an accessed field using a sequence of field and array 177 * indicies, separated by colon (:). It's conceptually very close to LLVM's 178 * getelementptr ([0]) instruction's arguments for identifying offset to 179 * a field. 180 * 181 * Example to provide a better feel. 182 * 183 * struct sample { 184 * int a; 185 * struct { 186 * int b[10]; 187 * }; 188 * }; 189 * 190 * struct sample *s = ...; 191 * int x = &s->a; // encoded as "0:0" (a is field #0) 192 * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, 193 * // b is field #0 inside anon struct, accessing elem #5) 194 * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) 195 * 196 * type_id for all relocs in this example will capture BTF type id of 197 * `struct sample`. 198 * 199 * Such relocation is emitted when using __builtin_preserve_access_index() 200 * Clang built-in, passing expression that captures field address, e.g.: 201 * 202 * bpf_probe_read(&dst, sizeof(dst), 203 * __builtin_preserve_access_index(&src->a.b.c)); 204 * 205 * In this case Clang will emit field relocation recording necessary data to 206 * be able to find offset of embedded `a.b.c` field within `src` struct. 207 * 208 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction 209 */ 210 struct bpf_field_reloc { 211 __u32 insn_off; 212 __u32 type_id; 213 __u32 access_str_off; 214 enum bpf_field_info_kind kind; 215 }; 216 217 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 218