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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#include "bpf_helpers.h"6 7/*8 * enum bpf_field_info_kind is passed as a second argument into9 * __builtin_preserve_field_info() built-in to get a specific aspect of10 * a field, captured as a first argument. __builtin_preserve_field_info(field,11 * info_kind) returns __u32 integer and produces BTF field relocation, which12 * is understood and processed by libbpf during BPF object loading. See13 * selftests/bpf for examples.14 */15enum bpf_field_info_kind {16 BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */17 BPF_FIELD_BYTE_SIZE = 1,18 BPF_FIELD_EXISTS = 2, /* field existence in target kernel */19 BPF_FIELD_SIGNED = 3,20 BPF_FIELD_LSHIFT_U64 = 4,21 BPF_FIELD_RSHIFT_U64 = 5,22};23 24/* second argument to __builtin_btf_type_id() built-in */25enum bpf_type_id_kind {26 BPF_TYPE_ID_LOCAL = 0, /* BTF type ID in local program */27 BPF_TYPE_ID_TARGET = 1, /* BTF type ID in target kernel */28};29 30/* second argument to __builtin_preserve_type_info() built-in */31enum bpf_type_info_kind {32 BPF_TYPE_EXISTS = 0, /* type existence in target kernel */33 BPF_TYPE_SIZE = 1, /* type size in target kernel */34 BPF_TYPE_MATCHES = 2, /* type match in target kernel */35};36 37/* second argument to __builtin_preserve_enum_value() built-in */38enum bpf_enum_value_kind {39 BPF_ENUMVAL_EXISTS = 0, /* enum value existence in kernel */40 BPF_ENUMVAL_VALUE = 1, /* enum value value relocation */41};42 43#define __CORE_RELO(src, field, info) \44 __builtin_preserve_field_info((src)->field, BPF_FIELD_##info)45 46#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__47#define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \48 bpf_probe_read_kernel( \49 (void *)dst, \50 __CORE_RELO(src, fld, BYTE_SIZE), \51 (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET))52#else53/* semantics of LSHIFT_64 assumes loading values into low-ordered bytes, so54 * for big-endian we need to adjust destination pointer accordingly, based on55 * field byte size56 */57#define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \58 bpf_probe_read_kernel( \59 (void *)dst + (8 - __CORE_RELO(src, fld, BYTE_SIZE)), \60 __CORE_RELO(src, fld, BYTE_SIZE), \61 (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET))62#endif63 64/*65 * Extract bitfield, identified by s->field, and return its value as u64.66 * All this is done in relocatable manner, so bitfield changes such as67 * signedness, bit size, offset changes, this will be handled automatically.68 * This version of macro is using bpf_probe_read_kernel() to read underlying69 * integer storage. Macro functions as an expression and its return type is70 * bpf_probe_read_kernel()'s return value: 0, on success, <0 on error.71 */72#define BPF_CORE_READ_BITFIELD_PROBED(s, field) ({ \73 unsigned long long val = 0; \74 \75 __CORE_BITFIELD_PROBE_READ(&val, s, field); \76 val <<= __CORE_RELO(s, field, LSHIFT_U64); \77 if (__CORE_RELO(s, field, SIGNED)) \78 val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64); \79 else \80 val = val >> __CORE_RELO(s, field, RSHIFT_U64); \81 val; \82})83 84/*85 * Extract bitfield, identified by s->field, and return its value as u64.86 * This version of macro is using direct memory reads and should be used from87 * BPF program types that support such functionality (e.g., typed raw88 * tracepoints).89 */90#define BPF_CORE_READ_BITFIELD(s, field) ({ \91 const void *p = (const void *)s + __CORE_RELO(s, field, BYTE_OFFSET); \92 unsigned long long val; \93 \94 /* This is a so-called barrier_var() operation that makes specified \95 * variable "a black box" for optimizing compiler. \96 * It forces compiler to perform BYTE_OFFSET relocation on p and use \97 * its calculated value in the switch below, instead of applying \98 * the same relocation 4 times for each individual memory load. \99 */ \100 asm volatile("" : "=r"(p) : "0"(p)); \101 \102 switch (__CORE_RELO(s, field, BYTE_SIZE)) { \103 case 1: val = *(const unsigned char *)p; break; \104 case 2: val = *(const unsigned short *)p; break; \105 case 4: val = *(const unsigned int *)p; break; \106 case 8: val = *(const unsigned long long *)p; break; \107 default: val = 0; break; \108 } \109 val <<= __CORE_RELO(s, field, LSHIFT_U64); \110 if (__CORE_RELO(s, field, SIGNED)) \111 val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64); \112 else \113 val = val >> __CORE_RELO(s, field, RSHIFT_U64); \114 val; \115})116 117/*118 * Write to a bitfield, identified by s->field.119 * This is the inverse of BPF_CORE_WRITE_BITFIELD().120 */121#define BPF_CORE_WRITE_BITFIELD(s, field, new_val) ({ \122 void *p = (void *)s + __CORE_RELO(s, field, BYTE_OFFSET); \123 unsigned int byte_size = __CORE_RELO(s, field, BYTE_SIZE); \124 unsigned int lshift = __CORE_RELO(s, field, LSHIFT_U64); \125 unsigned int rshift = __CORE_RELO(s, field, RSHIFT_U64); \126 unsigned long long mask, val, nval = new_val; \127 unsigned int rpad = rshift - lshift; \128 \129 asm volatile("" : "+r"(p)); \130 \131 switch (byte_size) { \132 case 1: val = *(unsigned char *)p; break; \133 case 2: val = *(unsigned short *)p; break; \134 case 4: val = *(unsigned int *)p; break; \135 case 8: val = *(unsigned long long *)p; break; \136 } \137 \138 mask = (~0ULL << rshift) >> lshift; \139 val = (val & ~mask) | ((nval << rpad) & mask); \140 \141 switch (byte_size) { \142 case 1: *(unsigned char *)p = val; break; \143 case 2: *(unsigned short *)p = val; break; \144 case 4: *(unsigned int *)p = val; break; \145 case 8: *(unsigned long long *)p = val; break; \146 } \147})148 149/* Differentiator between compilers builtin implementations. This is a150 * requirement due to the compiler parsing differences where GCC optimizes151 * early in parsing those constructs of type pointers to the builtin specific152 * type, resulting in not being possible to collect the required type153 * information in the builtin expansion.154 */155#ifdef __clang__156#define ___bpf_typeof(type) ((typeof(type) *) 0)157#else158#define ___bpf_typeof1(type, NR) ({ \159 extern typeof(type) *___concat(bpf_type_tmp_, NR); \160 ___concat(bpf_type_tmp_, NR); \161})162#define ___bpf_typeof(type) ___bpf_typeof1(type, __COUNTER__)163#endif164 165#ifdef __clang__166#define ___bpf_field_ref1(field) (field)167#define ___bpf_field_ref2(type, field) (___bpf_typeof(type)->field)168#else169#define ___bpf_field_ref1(field) (&(field))170#define ___bpf_field_ref2(type, field) (&(___bpf_typeof(type)->field))171#endif172#define ___bpf_field_ref(args...) \173 ___bpf_apply(___bpf_field_ref, ___bpf_narg(args))(args)174 175/*176 * Convenience macro to check that field actually exists in target kernel's.177 * Returns:178 * 1, if matching field is present in target kernel;179 * 0, if no matching field found.180 *181 * Supports two forms:182 * - field reference through variable access:183 * bpf_core_field_exists(p->my_field);184 * - field reference through type and field names:185 * bpf_core_field_exists(struct my_type, my_field).186 */187#define bpf_core_field_exists(field...) \188 __builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_EXISTS)189 190/*191 * Convenience macro to get the byte size of a field. Works for integers,192 * struct/unions, pointers, arrays, and enums.193 *194 * Supports two forms:195 * - field reference through variable access:196 * bpf_core_field_size(p->my_field);197 * - field reference through type and field names:198 * bpf_core_field_size(struct my_type, my_field).199 */200#define bpf_core_field_size(field...) \201 __builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_BYTE_SIZE)202 203/*204 * Convenience macro to get field's byte offset.205 *206 * Supports two forms:207 * - field reference through variable access:208 * bpf_core_field_offset(p->my_field);209 * - field reference through type and field names:210 * bpf_core_field_offset(struct my_type, my_field).211 */212#define bpf_core_field_offset(field...) \213 __builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_BYTE_OFFSET)214 215/*216 * Convenience macro to get BTF type ID of a specified type, using a local BTF217 * information. Return 32-bit unsigned integer with type ID from program's own218 * BTF. Always succeeds.219 */220#define bpf_core_type_id_local(type) \221 __builtin_btf_type_id(*___bpf_typeof(type), BPF_TYPE_ID_LOCAL)222 223/*224 * Convenience macro to get BTF type ID of a target kernel's type that matches225 * specified local type.226 * Returns:227 * - valid 32-bit unsigned type ID in kernel BTF;228 * - 0, if no matching type was found in a target kernel BTF.229 */230#define bpf_core_type_id_kernel(type) \231 __builtin_btf_type_id(*___bpf_typeof(type), BPF_TYPE_ID_TARGET)232 233/*234 * Convenience macro to check that provided named type235 * (struct/union/enum/typedef) exists in a target kernel.236 * Returns:237 * 1, if such type is present in target kernel's BTF;238 * 0, if no matching type is found.239 */240#define bpf_core_type_exists(type) \241 __builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_EXISTS)242 243/*244 * Convenience macro to check that provided named type245 * (struct/union/enum/typedef) "matches" that in a target kernel.246 * Returns:247 * 1, if the type matches in the target kernel's BTF;248 * 0, if the type does not match any in the target kernel249 */250#define bpf_core_type_matches(type) \251 __builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_MATCHES)252 253/*254 * Convenience macro to get the byte size of a provided named type255 * (struct/union/enum/typedef) in a target kernel.256 * Returns:257 * >= 0 size (in bytes), if type is present in target kernel's BTF;258 * 0, if no matching type is found.259 */260#define bpf_core_type_size(type) \261 __builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_SIZE)262 263/*264 * Convenience macro to check that provided enumerator value is defined in265 * a target kernel.266 * Returns:267 * 1, if specified enum type and its enumerator value are present in target268 * kernel's BTF;269 * 0, if no matching enum and/or enum value within that enum is found.270 */271#ifdef __clang__272#define bpf_core_enum_value_exists(enum_type, enum_value) \273 __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS)274#else275#define bpf_core_enum_value_exists(enum_type, enum_value) \276 __builtin_preserve_enum_value(___bpf_typeof(enum_type), enum_value, BPF_ENUMVAL_EXISTS)277#endif278 279/*280 * Convenience macro to get the integer value of an enumerator value in281 * a target kernel.282 * Returns:283 * 64-bit value, if specified enum type and its enumerator value are284 * present in target kernel's BTF;285 * 0, if no matching enum and/or enum value within that enum is found.286 */287#ifdef __clang__288#define bpf_core_enum_value(enum_type, enum_value) \289 __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_VALUE)290#else291#define bpf_core_enum_value(enum_type, enum_value) \292 __builtin_preserve_enum_value(___bpf_typeof(enum_type), enum_value, BPF_ENUMVAL_VALUE)293#endif294 295/*296 * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures297 * offset relocation for source address using __builtin_preserve_access_index()298 * built-in, provided by Clang.299 *300 * __builtin_preserve_access_index() takes as an argument an expression of301 * taking an address of a field within struct/union. It makes compiler emit302 * a relocation, which records BTF type ID describing root struct/union and an303 * accessor string which describes exact embedded field that was used to take304 * an address. See detailed description of this relocation format and305 * semantics in comments to struct bpf_core_relo in include/uapi/linux/bpf.h.306 *307 * This relocation allows libbpf to adjust BPF instruction to use correct308 * actual field offset, based on target kernel BTF type that matches original309 * (local) BTF, used to record relocation.310 */311#define bpf_core_read(dst, sz, src) \312 bpf_probe_read_kernel(dst, sz, (const void *)__builtin_preserve_access_index(src))313 314/* NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. */315#define bpf_core_read_user(dst, sz, src) \316 bpf_probe_read_user(dst, sz, (const void *)__builtin_preserve_access_index(src))317/*318 * bpf_core_read_str() is a thin wrapper around bpf_probe_read_str()319 * additionally emitting BPF CO-RE field relocation for specified source320 * argument.321 */322#define bpf_core_read_str(dst, sz, src) \323 bpf_probe_read_kernel_str(dst, sz, (const void *)__builtin_preserve_access_index(src))324 325/* NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. */326#define bpf_core_read_user_str(dst, sz, src) \327 bpf_probe_read_user_str(dst, sz, (const void *)__builtin_preserve_access_index(src))328 329extern void *bpf_rdonly_cast(const void *obj, __u32 btf_id) __ksym __weak;330 331/*332 * Cast provided pointer *ptr* into a pointer to a specified *type* in such333 * a way that BPF verifier will become aware of associated kernel-side BTF334 * type. This allows to access members of kernel types directly without the335 * need to use BPF_CORE_READ() macros.336 */337#define bpf_core_cast(ptr, type) \338 ((typeof(type) *)bpf_rdonly_cast((ptr), bpf_core_type_id_kernel(type)))339 340#define ___concat(a, b) a ## b341#define ___apply(fn, n) ___concat(fn, n)342#define ___nth(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, __11, N, ...) N343 344/*345 * return number of provided arguments; used for switch-based variadic macro346 * definitions (see ___last, ___arrow, etc below)347 */348#define ___narg(...) ___nth(_, ##__VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)349/*350 * return 0 if no arguments are passed, N - otherwise; used for351 * recursively-defined macros to specify termination (0) case, and generic352 * (N) case (e.g., ___read_ptrs, ___core_read)353 */354#define ___empty(...) ___nth(_, ##__VA_ARGS__, N, N, N, N, N, N, N, N, N, N, 0)355 356#define ___last1(x) x357#define ___last2(a, x) x358#define ___last3(a, b, x) x359#define ___last4(a, b, c, x) x360#define ___last5(a, b, c, d, x) x361#define ___last6(a, b, c, d, e, x) x362#define ___last7(a, b, c, d, e, f, x) x363#define ___last8(a, b, c, d, e, f, g, x) x364#define ___last9(a, b, c, d, e, f, g, h, x) x365#define ___last10(a, b, c, d, e, f, g, h, i, x) x366#define ___last(...) ___apply(___last, ___narg(__VA_ARGS__))(__VA_ARGS__)367 368#define ___nolast2(a, _) a369#define ___nolast3(a, b, _) a, b370#define ___nolast4(a, b, c, _) a, b, c371#define ___nolast5(a, b, c, d, _) a, b, c, d372#define ___nolast6(a, b, c, d, e, _) a, b, c, d, e373#define ___nolast7(a, b, c, d, e, f, _) a, b, c, d, e, f374#define ___nolast8(a, b, c, d, e, f, g, _) a, b, c, d, e, f, g375#define ___nolast9(a, b, c, d, e, f, g, h, _) a, b, c, d, e, f, g, h376#define ___nolast10(a, b, c, d, e, f, g, h, i, _) a, b, c, d, e, f, g, h, i377#define ___nolast(...) ___apply(___nolast, ___narg(__VA_ARGS__))(__VA_ARGS__)378 379#define ___arrow1(a) a380#define ___arrow2(a, b) a->b381#define ___arrow3(a, b, c) a->b->c382#define ___arrow4(a, b, c, d) a->b->c->d383#define ___arrow5(a, b, c, d, e) a->b->c->d->e384#define ___arrow6(a, b, c, d, e, f) a->b->c->d->e->f385#define ___arrow7(a, b, c, d, e, f, g) a->b->c->d->e->f->g386#define ___arrow8(a, b, c, d, e, f, g, h) a->b->c->d->e->f->g->h387#define ___arrow9(a, b, c, d, e, f, g, h, i) a->b->c->d->e->f->g->h->i388#define ___arrow10(a, b, c, d, e, f, g, h, i, j) a->b->c->d->e->f->g->h->i->j389#define ___arrow(...) ___apply(___arrow, ___narg(__VA_ARGS__))(__VA_ARGS__)390 391#define ___type(...) typeof(___arrow(__VA_ARGS__))392 393#define ___read(read_fn, dst, src_type, src, accessor) \394 read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor)395 396/* "recursively" read a sequence of inner pointers using local __t var */397#define ___rd_first(fn, src, a) ___read(fn, &__t, ___type(src), src, a);398#define ___rd_last(fn, ...) \399 ___read(fn, &__t, ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__));400#define ___rd_p1(fn, ...) const void *__t; ___rd_first(fn, __VA_ARGS__)401#define ___rd_p2(fn, ...) ___rd_p1(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)402#define ___rd_p3(fn, ...) ___rd_p2(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)403#define ___rd_p4(fn, ...) ___rd_p3(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)404#define ___rd_p5(fn, ...) ___rd_p4(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)405#define ___rd_p6(fn, ...) ___rd_p5(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)406#define ___rd_p7(fn, ...) ___rd_p6(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)407#define ___rd_p8(fn, ...) ___rd_p7(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)408#define ___rd_p9(fn, ...) ___rd_p8(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)409#define ___read_ptrs(fn, src, ...) \410 ___apply(___rd_p, ___narg(__VA_ARGS__))(fn, src, __VA_ARGS__)411 412#define ___core_read0(fn, fn_ptr, dst, src, a) \413 ___read(fn, dst, ___type(src), src, a);414#define ___core_readN(fn, fn_ptr, dst, src, ...) \415 ___read_ptrs(fn_ptr, src, ___nolast(__VA_ARGS__)) \416 ___read(fn, dst, ___type(src, ___nolast(__VA_ARGS__)), __t, \417 ___last(__VA_ARGS__));418#define ___core_read(fn, fn_ptr, dst, src, a, ...) \419 ___apply(___core_read, ___empty(__VA_ARGS__))(fn, fn_ptr, dst, \420 src, a, ##__VA_ARGS__)421 422/*423 * BPF_CORE_READ_INTO() is a more performance-conscious variant of424 * BPF_CORE_READ(), in which final field is read into user-provided storage.425 * See BPF_CORE_READ() below for more details on general usage.426 */427#define BPF_CORE_READ_INTO(dst, src, a, ...) ({ \428 ___core_read(bpf_core_read, bpf_core_read, \429 dst, (src), a, ##__VA_ARGS__) \430})431 432/*433 * Variant of BPF_CORE_READ_INTO() for reading from user-space memory.434 *435 * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use.436 */437#define BPF_CORE_READ_USER_INTO(dst, src, a, ...) ({ \438 ___core_read(bpf_core_read_user, bpf_core_read_user, \439 dst, (src), a, ##__VA_ARGS__) \440})441 442/* Non-CO-RE variant of BPF_CORE_READ_INTO() */443#define BPF_PROBE_READ_INTO(dst, src, a, ...) ({ \444 ___core_read(bpf_probe_read_kernel, bpf_probe_read_kernel, \445 dst, (src), a, ##__VA_ARGS__) \446})447 448/* Non-CO-RE variant of BPF_CORE_READ_USER_INTO().449 *450 * As no CO-RE relocations are emitted, source types can be arbitrary and are451 * not restricted to kernel types only.452 */453#define BPF_PROBE_READ_USER_INTO(dst, src, a, ...) ({ \454 ___core_read(bpf_probe_read_user, bpf_probe_read_user, \455 dst, (src), a, ##__VA_ARGS__) \456})457 458/*459 * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as460 * BPF_CORE_READ() for intermediate pointers, but then executes (and returns461 * corresponding error code) bpf_core_read_str() for final string read.462 */463#define BPF_CORE_READ_STR_INTO(dst, src, a, ...) ({ \464 ___core_read(bpf_core_read_str, bpf_core_read, \465 dst, (src), a, ##__VA_ARGS__) \466})467 468/*469 * Variant of BPF_CORE_READ_STR_INTO() for reading from user-space memory.470 *471 * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use.472 */473#define BPF_CORE_READ_USER_STR_INTO(dst, src, a, ...) ({ \474 ___core_read(bpf_core_read_user_str, bpf_core_read_user, \475 dst, (src), a, ##__VA_ARGS__) \476})477 478/* Non-CO-RE variant of BPF_CORE_READ_STR_INTO() */479#define BPF_PROBE_READ_STR_INTO(dst, src, a, ...) ({ \480 ___core_read(bpf_probe_read_kernel_str, bpf_probe_read_kernel, \481 dst, (src), a, ##__VA_ARGS__) \482})483 484/*485 * Non-CO-RE variant of BPF_CORE_READ_USER_STR_INTO().486 *487 * As no CO-RE relocations are emitted, source types can be arbitrary and are488 * not restricted to kernel types only.489 */490#define BPF_PROBE_READ_USER_STR_INTO(dst, src, a, ...) ({ \491 ___core_read(bpf_probe_read_user_str, bpf_probe_read_user, \492 dst, (src), a, ##__VA_ARGS__) \493})494 495/*496 * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially497 * when there are few pointer chasing steps.498 * E.g., what in non-BPF world (or in BPF w/ BCC) would be something like:499 * int x = s->a.b.c->d.e->f->g;500 * can be succinctly achieved using BPF_CORE_READ as:501 * int x = BPF_CORE_READ(s, a.b.c, d.e, f, g);502 *503 * BPF_CORE_READ will decompose above statement into 4 bpf_core_read (BPF504 * CO-RE relocatable bpf_probe_read_kernel() wrapper) calls, logically505 * equivalent to:506 * 1. const void *__t = s->a.b.c;507 * 2. __t = __t->d.e;508 * 3. __t = __t->f;509 * 4. return __t->g;510 *511 * Equivalence is logical, because there is a heavy type casting/preservation512 * involved, as well as all the reads are happening through513 * bpf_probe_read_kernel() calls using __builtin_preserve_access_index() to514 * emit CO-RE relocations.515 *516 * N.B. Only up to 9 "field accessors" are supported, which should be more517 * than enough for any practical purpose.518 */519#define BPF_CORE_READ(src, a, ...) ({ \520 ___type((src), a, ##__VA_ARGS__) __r; \521 BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \522 __r; \523})524 525/*526 * Variant of BPF_CORE_READ() for reading from user-space memory.527 *528 * NOTE: all the source types involved are still *kernel types* and need to529 * exist in kernel (or kernel module) BTF, otherwise CO-RE relocation will530 * fail. Custom user types are not relocatable with CO-RE.531 * The typical situation in which BPF_CORE_READ_USER() might be used is to532 * read kernel UAPI types from the user-space memory passed in as a syscall533 * input argument.534 */535#define BPF_CORE_READ_USER(src, a, ...) ({ \536 ___type((src), a, ##__VA_ARGS__) __r; \537 BPF_CORE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__); \538 __r; \539})540 541/* Non-CO-RE variant of BPF_CORE_READ() */542#define BPF_PROBE_READ(src, a, ...) ({ \543 ___type((src), a, ##__VA_ARGS__) __r; \544 BPF_PROBE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \545 __r; \546})547 548/*549 * Non-CO-RE variant of BPF_CORE_READ_USER().550 *551 * As no CO-RE relocations are emitted, source types can be arbitrary and are552 * not restricted to kernel types only.553 */554#define BPF_PROBE_READ_USER(src, a, ...) ({ \555 ___type((src), a, ##__VA_ARGS__) __r; \556 BPF_PROBE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__); \557 __r; \558})559 560#endif561 562