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_warning(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 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 67 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 68 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 69 const char *str_sec, size_t str_len); 70 71 struct btf_ext_info { 72 /* 73 * info points to the individual info section (e.g. func_info and 74 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 75 */ 76 void *info; 77 __u32 rec_size; 78 __u32 len; 79 }; 80 81 #define for_each_btf_ext_sec(seg, sec) \ 82 for (sec = (seg)->info; \ 83 (void *)sec < (seg)->info + (seg)->len; \ 84 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 85 (seg)->rec_size * sec->num_info) 86 87 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 88 for (i = 0, rec = (void *)&(sec)->data; \ 89 i < (sec)->num_info; \ 90 i++, rec = (void *)rec + (seg)->rec_size) 91 92 struct btf_ext { 93 union { 94 struct btf_ext_header *hdr; 95 void *data; 96 }; 97 struct btf_ext_info func_info; 98 struct btf_ext_info line_info; 99 struct btf_ext_info offset_reloc_info; 100 __u32 data_size; 101 }; 102 103 struct btf_ext_info_sec { 104 __u32 sec_name_off; 105 __u32 num_info; 106 /* Followed by num_info * record_size number of bytes */ 107 __u8 data[0]; 108 }; 109 110 /* The minimum bpf_func_info checked by the loader */ 111 struct bpf_func_info_min { 112 __u32 insn_off; 113 __u32 type_id; 114 }; 115 116 /* The minimum bpf_line_info checked by the loader */ 117 struct bpf_line_info_min { 118 __u32 insn_off; 119 __u32 file_name_off; 120 __u32 line_off; 121 __u32 line_col; 122 }; 123 124 /* The minimum bpf_offset_reloc checked by the loader 125 * 126 * Offset relocation captures the following data: 127 * - insn_off - instruction offset (in bytes) within a BPF program that needs 128 * its insn->imm field to be relocated with actual offset; 129 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable 130 * offset; 131 * - access_str_off - offset into corresponding .BTF string section. String 132 * itself encodes an accessed field using a sequence of field and array 133 * indicies, separated by colon (:). It's conceptually very close to LLVM's 134 * getelementptr ([0]) instruction's arguments for identifying offset to 135 * a field. 136 * 137 * Example to provide a better feel. 138 * 139 * struct sample { 140 * int a; 141 * struct { 142 * int b[10]; 143 * }; 144 * }; 145 * 146 * struct sample *s = ...; 147 * int x = &s->a; // encoded as "0:0" (a is field #0) 148 * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, 149 * // b is field #0 inside anon struct, accessing elem #5) 150 * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) 151 * 152 * type_id for all relocs in this example will capture BTF type id of 153 * `struct sample`. 154 * 155 * Such relocation is emitted when using __builtin_preserve_access_index() 156 * Clang built-in, passing expression that captures field address, e.g.: 157 * 158 * bpf_probe_read(&dst, sizeof(dst), 159 * __builtin_preserve_access_index(&src->a.b.c)); 160 * 161 * In this case Clang will emit offset relocation recording necessary data to 162 * be able to find offset of embedded `a.b.c` field within `src` struct. 163 * 164 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction 165 */ 166 struct bpf_offset_reloc { 167 __u32 insn_off; 168 __u32 type_id; 169 __u32 access_str_off; 170 }; 171 172 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 173