1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 #ifndef __BPF_CORE_READ_H__ 3 #define __BPF_CORE_READ_H__ 4 5 /* 6 * enum bpf_field_info_kind is passed as a second argument into 7 * __builtin_preserve_field_info() built-in to get a specific aspect of 8 * a field, captured as a first argument. __builtin_preserve_field_info(field, 9 * info_kind) returns __u32 integer and produces BTF field relocation, which 10 * is understood and processed by libbpf during BPF object loading. See 11 * selftests/bpf for examples. 12 */ 13 enum bpf_field_info_kind { 14 BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ 15 BPF_FIELD_BYTE_SIZE = 1, 16 BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ 17 BPF_FIELD_SIGNED = 3, 18 BPF_FIELD_LSHIFT_U64 = 4, 19 BPF_FIELD_RSHIFT_U64 = 5, 20 }; 21 22 /* second argument to __builtin_btf_type_id() built-in */ 23 enum bpf_type_id_kind { 24 BPF_TYPE_ID_LOCAL = 0, /* BTF type ID in local program */ 25 BPF_TYPE_ID_TARGET = 1, /* BTF type ID in target kernel */ 26 }; 27 28 /* second argument to __builtin_preserve_type_info() built-in */ 29 enum bpf_type_info_kind { 30 BPF_TYPE_EXISTS = 0, /* type existence in target kernel */ 31 BPF_TYPE_SIZE = 1, /* type size in target kernel */ 32 BPF_TYPE_MATCHES = 2, /* type match in target kernel */ 33 }; 34 35 /* second argument to __builtin_preserve_enum_value() built-in */ 36 enum bpf_enum_value_kind { 37 BPF_ENUMVAL_EXISTS = 0, /* enum value existence in kernel */ 38 BPF_ENUMVAL_VALUE = 1, /* enum value value relocation */ 39 }; 40 41 #define __CORE_RELO(src, field, info) \ 42 __builtin_preserve_field_info((src)->field, BPF_FIELD_##info) 43 44 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ 45 #define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ 46 bpf_probe_read_kernel( \ 47 (void *)dst, \ 48 __CORE_RELO(src, fld, BYTE_SIZE), \ 49 (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) 50 #else 51 /* semantics of LSHIFT_64 assumes loading values into low-ordered bytes, so 52 * for big-endian we need to adjust destination pointer accordingly, based on 53 * field byte size 54 */ 55 #define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ 56 bpf_probe_read_kernel( \ 57 (void *)dst + (8 - __CORE_RELO(src, fld, BYTE_SIZE)), \ 58 __CORE_RELO(src, fld, BYTE_SIZE), \ 59 (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) 60 #endif 61 62 /* 63 * Extract bitfield, identified by s->field, and return its value as u64. 64 * All this is done in relocatable manner, so bitfield changes such as 65 * signedness, bit size, offset changes, this will be handled automatically. 66 * This version of macro is using bpf_probe_read_kernel() to read underlying 67 * integer storage. Macro functions as an expression and its return type is 68 * bpf_probe_read_kernel()'s return value: 0, on success, <0 on error. 69 */ 70 #define BPF_CORE_READ_BITFIELD_PROBED(s, field) ({ \ 71 unsigned long long val = 0; \ 72 \ 73 __CORE_BITFIELD_PROBE_READ(&val, s, field); \ 74 val <<= __CORE_RELO(s, field, LSHIFT_U64); \ 75 if (__CORE_RELO(s, field, SIGNED)) \ 76 val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64); \ 77 else \ 78 val = val >> __CORE_RELO(s, field, RSHIFT_U64); \ 79 val; \ 80 }) 81 82 /* 83 * Extract bitfield, identified by s->field, and return its value as u64. 84 * This version of macro is using direct memory reads and should be used from 85 * BPF program types that support such functionality (e.g., typed raw 86 * tracepoints). 87 */ 88 #define BPF_CORE_READ_BITFIELD(s, field) ({ \ 89 const void *p = (const void *)s + __CORE_RELO(s, field, BYTE_OFFSET); \ 90 unsigned long long val; \ 91 \ 92 /* This is a so-called barrier_var() operation that makes specified \ 93 * variable "a black box" for optimizing compiler. \ 94 * It forces compiler to perform BYTE_OFFSET relocation on p and use \ 95 * its calculated value in the switch below, instead of applying \ 96 * the same relocation 4 times for each individual memory load. \ 97 */ \ 98 asm volatile("" : "=r"(p) : "0"(p)); \ 99 \ 100 switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ 101 case 1: val = *(const unsigned char *)p; break; \ 102 case 2: val = *(const unsigned short *)p; break; \ 103 case 4: val = *(const unsigned int *)p; break; \ 104 case 8: val = *(const unsigned long long *)p; break; \ 105 default: val = 0; break; \ 106 } \ 107 val <<= __CORE_RELO(s, field, LSHIFT_U64); \ 108 if (__CORE_RELO(s, field, SIGNED)) \ 109 val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64); \ 110 else \ 111 val = val >> __CORE_RELO(s, field, RSHIFT_U64); \ 112 val; \ 113 }) 114 115 #define ___bpf_field_ref1(field) (field) 116 #define ___bpf_field_ref2(type, field) (((typeof(type) *)0)->field) 117 #define ___bpf_field_ref(args...) \ 118 ___bpf_apply(___bpf_field_ref, ___bpf_narg(args))(args) 119 120 /* 121 * Convenience macro to check that field actually exists in target kernel's. 122 * Returns: 123 * 1, if matching field is present in target kernel; 124 * 0, if no matching field found. 125 * 126 * Supports two forms: 127 * - field reference through variable access: 128 * bpf_core_field_exists(p->my_field); 129 * - field reference through type and field names: 130 * bpf_core_field_exists(struct my_type, my_field). 131 */ 132 #define bpf_core_field_exists(field...) \ 133 __builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_EXISTS) 134 135 /* 136 * Convenience macro to get the byte size of a field. Works for integers, 137 * struct/unions, pointers, arrays, and enums. 138 * 139 * Supports two forms: 140 * - field reference through variable access: 141 * bpf_core_field_size(p->my_field); 142 * - field reference through type and field names: 143 * bpf_core_field_size(struct my_type, my_field). 144 */ 145 #define bpf_core_field_size(field...) \ 146 __builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_BYTE_SIZE) 147 148 /* 149 * Convenience macro to get field's byte offset. 150 * 151 * Supports two forms: 152 * - field reference through variable access: 153 * bpf_core_field_offset(p->my_field); 154 * - field reference through type and field names: 155 * bpf_core_field_offset(struct my_type, my_field). 156 */ 157 #define bpf_core_field_offset(field...) \ 158 __builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_BYTE_OFFSET) 159 160 /* 161 * Convenience macro to get BTF type ID of a specified type, using a local BTF 162 * information. Return 32-bit unsigned integer with type ID from program's own 163 * BTF. Always succeeds. 164 */ 165 #define bpf_core_type_id_local(type) \ 166 __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_LOCAL) 167 168 /* 169 * Convenience macro to get BTF type ID of a target kernel's type that matches 170 * specified local type. 171 * Returns: 172 * - valid 32-bit unsigned type ID in kernel BTF; 173 * - 0, if no matching type was found in a target kernel BTF. 174 */ 175 #define bpf_core_type_id_kernel(type) \ 176 __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_TARGET) 177 178 /* 179 * Convenience macro to check that provided named type 180 * (struct/union/enum/typedef) exists in a target kernel. 181 * Returns: 182 * 1, if such type is present in target kernel's BTF; 183 * 0, if no matching type is found. 184 */ 185 #define bpf_core_type_exists(type) \ 186 __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_EXISTS) 187 188 /* 189 * Convenience macro to check that provided named type 190 * (struct/union/enum/typedef) "matches" that in a target kernel. 191 * Returns: 192 * 1, if the type matches in the target kernel's BTF; 193 * 0, if the type does not match any in the target kernel 194 */ 195 #define bpf_core_type_matches(type) \ 196 __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_MATCHES) 197 198 /* 199 * Convenience macro to get the byte size of a provided named type 200 * (struct/union/enum/typedef) in a target kernel. 201 * Returns: 202 * >= 0 size (in bytes), if type is present in target kernel's BTF; 203 * 0, if no matching type is found. 204 */ 205 #define bpf_core_type_size(type) \ 206 __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_SIZE) 207 208 /* 209 * Convenience macro to check that provided enumerator value is defined in 210 * a target kernel. 211 * Returns: 212 * 1, if specified enum type and its enumerator value are present in target 213 * kernel's BTF; 214 * 0, if no matching enum and/or enum value within that enum is found. 215 */ 216 #define bpf_core_enum_value_exists(enum_type, enum_value) \ 217 __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS) 218 219 /* 220 * Convenience macro to get the integer value of an enumerator value in 221 * a target kernel. 222 * Returns: 223 * 64-bit value, if specified enum type and its enumerator value are 224 * present in target kernel's BTF; 225 * 0, if no matching enum and/or enum value within that enum is found. 226 */ 227 #define bpf_core_enum_value(enum_type, enum_value) \ 228 __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_VALUE) 229 230 /* 231 * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures 232 * offset relocation for source address using __builtin_preserve_access_index() 233 * built-in, provided by Clang. 234 * 235 * __builtin_preserve_access_index() takes as an argument an expression of 236 * taking an address of a field within struct/union. It makes compiler emit 237 * a relocation, which records BTF type ID describing root struct/union and an 238 * accessor string which describes exact embedded field that was used to take 239 * an address. See detailed description of this relocation format and 240 * semantics in comments to struct bpf_field_reloc in libbpf_internal.h. 241 * 242 * This relocation allows libbpf to adjust BPF instruction to use correct 243 * actual field offset, based on target kernel BTF type that matches original 244 * (local) BTF, used to record relocation. 245 */ 246 #define bpf_core_read(dst, sz, src) \ 247 bpf_probe_read_kernel(dst, sz, (const void *)__builtin_preserve_access_index(src)) 248 249 /* NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. */ 250 #define bpf_core_read_user(dst, sz, src) \ 251 bpf_probe_read_user(dst, sz, (const void *)__builtin_preserve_access_index(src)) 252 /* 253 * bpf_core_read_str() is a thin wrapper around bpf_probe_read_str() 254 * additionally emitting BPF CO-RE field relocation for specified source 255 * argument. 256 */ 257 #define bpf_core_read_str(dst, sz, src) \ 258 bpf_probe_read_kernel_str(dst, sz, (const void *)__builtin_preserve_access_index(src)) 259 260 /* NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. */ 261 #define bpf_core_read_user_str(dst, sz, src) \ 262 bpf_probe_read_user_str(dst, sz, (const void *)__builtin_preserve_access_index(src)) 263 264 #define ___concat(a, b) a ## b 265 #define ___apply(fn, n) ___concat(fn, n) 266 #define ___nth(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, __11, N, ...) N 267 268 /* 269 * return number of provided arguments; used for switch-based variadic macro 270 * definitions (see ___last, ___arrow, etc below) 271 */ 272 #define ___narg(...) ___nth(_, ##__VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) 273 /* 274 * return 0 if no arguments are passed, N - otherwise; used for 275 * recursively-defined macros to specify termination (0) case, and generic 276 * (N) case (e.g., ___read_ptrs, ___core_read) 277 */ 278 #define ___empty(...) ___nth(_, ##__VA_ARGS__, N, N, N, N, N, N, N, N, N, N, 0) 279 280 #define ___last1(x) x 281 #define ___last2(a, x) x 282 #define ___last3(a, b, x) x 283 #define ___last4(a, b, c, x) x 284 #define ___last5(a, b, c, d, x) x 285 #define ___last6(a, b, c, d, e, x) x 286 #define ___last7(a, b, c, d, e, f, x) x 287 #define ___last8(a, b, c, d, e, f, g, x) x 288 #define ___last9(a, b, c, d, e, f, g, h, x) x 289 #define ___last10(a, b, c, d, e, f, g, h, i, x) x 290 #define ___last(...) ___apply(___last, ___narg(__VA_ARGS__))(__VA_ARGS__) 291 292 #define ___nolast2(a, _) a 293 #define ___nolast3(a, b, _) a, b 294 #define ___nolast4(a, b, c, _) a, b, c 295 #define ___nolast5(a, b, c, d, _) a, b, c, d 296 #define ___nolast6(a, b, c, d, e, _) a, b, c, d, e 297 #define ___nolast7(a, b, c, d, e, f, _) a, b, c, d, e, f 298 #define ___nolast8(a, b, c, d, e, f, g, _) a, b, c, d, e, f, g 299 #define ___nolast9(a, b, c, d, e, f, g, h, _) a, b, c, d, e, f, g, h 300 #define ___nolast10(a, b, c, d, e, f, g, h, i, _) a, b, c, d, e, f, g, h, i 301 #define ___nolast(...) ___apply(___nolast, ___narg(__VA_ARGS__))(__VA_ARGS__) 302 303 #define ___arrow1(a) a 304 #define ___arrow2(a, b) a->b 305 #define ___arrow3(a, b, c) a->b->c 306 #define ___arrow4(a, b, c, d) a->b->c->d 307 #define ___arrow5(a, b, c, d, e) a->b->c->d->e 308 #define ___arrow6(a, b, c, d, e, f) a->b->c->d->e->f 309 #define ___arrow7(a, b, c, d, e, f, g) a->b->c->d->e->f->g 310 #define ___arrow8(a, b, c, d, e, f, g, h) a->b->c->d->e->f->g->h 311 #define ___arrow9(a, b, c, d, e, f, g, h, i) a->b->c->d->e->f->g->h->i 312 #define ___arrow10(a, b, c, d, e, f, g, h, i, j) a->b->c->d->e->f->g->h->i->j 313 #define ___arrow(...) ___apply(___arrow, ___narg(__VA_ARGS__))(__VA_ARGS__) 314 315 #define ___type(...) typeof(___arrow(__VA_ARGS__)) 316 317 #define ___read(read_fn, dst, src_type, src, accessor) \ 318 read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor) 319 320 /* "recursively" read a sequence of inner pointers using local __t var */ 321 #define ___rd_first(fn, src, a) ___read(fn, &__t, ___type(src), src, a); 322 #define ___rd_last(fn, ...) \ 323 ___read(fn, &__t, ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__)); 324 #define ___rd_p1(fn, ...) const void *__t; ___rd_first(fn, __VA_ARGS__) 325 #define ___rd_p2(fn, ...) ___rd_p1(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 326 #define ___rd_p3(fn, ...) ___rd_p2(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 327 #define ___rd_p4(fn, ...) ___rd_p3(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 328 #define ___rd_p5(fn, ...) ___rd_p4(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 329 #define ___rd_p6(fn, ...) ___rd_p5(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 330 #define ___rd_p7(fn, ...) ___rd_p6(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 331 #define ___rd_p8(fn, ...) ___rd_p7(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 332 #define ___rd_p9(fn, ...) ___rd_p8(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__) 333 #define ___read_ptrs(fn, src, ...) \ 334 ___apply(___rd_p, ___narg(__VA_ARGS__))(fn, src, __VA_ARGS__) 335 336 #define ___core_read0(fn, fn_ptr, dst, src, a) \ 337 ___read(fn, dst, ___type(src), src, a); 338 #define ___core_readN(fn, fn_ptr, dst, src, ...) \ 339 ___read_ptrs(fn_ptr, src, ___nolast(__VA_ARGS__)) \ 340 ___read(fn, dst, ___type(src, ___nolast(__VA_ARGS__)), __t, \ 341 ___last(__VA_ARGS__)); 342 #define ___core_read(fn, fn_ptr, dst, src, a, ...) \ 343 ___apply(___core_read, ___empty(__VA_ARGS__))(fn, fn_ptr, dst, \ 344 src, a, ##__VA_ARGS__) 345 346 /* 347 * BPF_CORE_READ_INTO() is a more performance-conscious variant of 348 * BPF_CORE_READ(), in which final field is read into user-provided storage. 349 * See BPF_CORE_READ() below for more details on general usage. 350 */ 351 #define BPF_CORE_READ_INTO(dst, src, a, ...) ({ \ 352 ___core_read(bpf_core_read, bpf_core_read, \ 353 dst, (src), a, ##__VA_ARGS__) \ 354 }) 355 356 /* 357 * Variant of BPF_CORE_READ_INTO() for reading from user-space memory. 358 * 359 * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. 360 */ 361 #define BPF_CORE_READ_USER_INTO(dst, src, a, ...) ({ \ 362 ___core_read(bpf_core_read_user, bpf_core_read_user, \ 363 dst, (src), a, ##__VA_ARGS__) \ 364 }) 365 366 /* Non-CO-RE variant of BPF_CORE_READ_INTO() */ 367 #define BPF_PROBE_READ_INTO(dst, src, a, ...) ({ \ 368 ___core_read(bpf_probe_read_kernel, bpf_probe_read_kernel, \ 369 dst, (src), a, ##__VA_ARGS__) \ 370 }) 371 372 /* Non-CO-RE variant of BPF_CORE_READ_USER_INTO(). 373 * 374 * As no CO-RE relocations are emitted, source types can be arbitrary and are 375 * not restricted to kernel types only. 376 */ 377 #define BPF_PROBE_READ_USER_INTO(dst, src, a, ...) ({ \ 378 ___core_read(bpf_probe_read_user, bpf_probe_read_user, \ 379 dst, (src), a, ##__VA_ARGS__) \ 380 }) 381 382 /* 383 * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as 384 * BPF_CORE_READ() for intermediate pointers, but then executes (and returns 385 * corresponding error code) bpf_core_read_str() for final string read. 386 */ 387 #define BPF_CORE_READ_STR_INTO(dst, src, a, ...) ({ \ 388 ___core_read(bpf_core_read_str, bpf_core_read, \ 389 dst, (src), a, ##__VA_ARGS__) \ 390 }) 391 392 /* 393 * Variant of BPF_CORE_READ_STR_INTO() for reading from user-space memory. 394 * 395 * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. 396 */ 397 #define BPF_CORE_READ_USER_STR_INTO(dst, src, a, ...) ({ \ 398 ___core_read(bpf_core_read_user_str, bpf_core_read_user, \ 399 dst, (src), a, ##__VA_ARGS__) \ 400 }) 401 402 /* Non-CO-RE variant of BPF_CORE_READ_STR_INTO() */ 403 #define BPF_PROBE_READ_STR_INTO(dst, src, a, ...) ({ \ 404 ___core_read(bpf_probe_read_kernel_str, bpf_probe_read_kernel, \ 405 dst, (src), a, ##__VA_ARGS__) \ 406 }) 407 408 /* 409 * Non-CO-RE variant of BPF_CORE_READ_USER_STR_INTO(). 410 * 411 * As no CO-RE relocations are emitted, source types can be arbitrary and are 412 * not restricted to kernel types only. 413 */ 414 #define BPF_PROBE_READ_USER_STR_INTO(dst, src, a, ...) ({ \ 415 ___core_read(bpf_probe_read_user_str, bpf_probe_read_user, \ 416 dst, (src), a, ##__VA_ARGS__) \ 417 }) 418 419 /* 420 * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially 421 * when there are few pointer chasing steps. 422 * E.g., what in non-BPF world (or in BPF w/ BCC) would be something like: 423 * int x = s->a.b.c->d.e->f->g; 424 * can be succinctly achieved using BPF_CORE_READ as: 425 * int x = BPF_CORE_READ(s, a.b.c, d.e, f, g); 426 * 427 * BPF_CORE_READ will decompose above statement into 4 bpf_core_read (BPF 428 * CO-RE relocatable bpf_probe_read_kernel() wrapper) calls, logically 429 * equivalent to: 430 * 1. const void *__t = s->a.b.c; 431 * 2. __t = __t->d.e; 432 * 3. __t = __t->f; 433 * 4. return __t->g; 434 * 435 * Equivalence is logical, because there is a heavy type casting/preservation 436 * involved, as well as all the reads are happening through 437 * bpf_probe_read_kernel() calls using __builtin_preserve_access_index() to 438 * emit CO-RE relocations. 439 * 440 * N.B. Only up to 9 "field accessors" are supported, which should be more 441 * than enough for any practical purpose. 442 */ 443 #define BPF_CORE_READ(src, a, ...) ({ \ 444 ___type((src), a, ##__VA_ARGS__) __r; \ 445 BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \ 446 __r; \ 447 }) 448 449 /* 450 * Variant of BPF_CORE_READ() for reading from user-space memory. 451 * 452 * NOTE: all the source types involved are still *kernel types* and need to 453 * exist in kernel (or kernel module) BTF, otherwise CO-RE relocation will 454 * fail. Custom user types are not relocatable with CO-RE. 455 * The typical situation in which BPF_CORE_READ_USER() might be used is to 456 * read kernel UAPI types from the user-space memory passed in as a syscall 457 * input argument. 458 */ 459 #define BPF_CORE_READ_USER(src, a, ...) ({ \ 460 ___type((src), a, ##__VA_ARGS__) __r; \ 461 BPF_CORE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__); \ 462 __r; \ 463 }) 464 465 /* Non-CO-RE variant of BPF_CORE_READ() */ 466 #define BPF_PROBE_READ(src, a, ...) ({ \ 467 ___type((src), a, ##__VA_ARGS__) __r; \ 468 BPF_PROBE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \ 469 __r; \ 470 }) 471 472 /* 473 * Non-CO-RE variant of BPF_CORE_READ_USER(). 474 * 475 * As no CO-RE relocations are emitted, source types can be arbitrary and are 476 * not restricted to kernel types only. 477 */ 478 #define BPF_PROBE_READ_USER(src, a, ...) ({ \ 479 ___type((src), a, ##__VA_ARGS__) __r; \ 480 BPF_PROBE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__); \ 481 __r; \ 482 }) 483 484 #endif 485 486