xref: /openbmc/linux/tools/lib/bpf/bpf_core_read.h (revision 44ad3baf1cca483e418b6aadf2d3994f69e0f16a)
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 #if defined(__clang__) && (__clang_major__ >= 19)
316 #define ___type(...) __typeof_unqual__(___arrow(__VA_ARGS__))
317 #elif defined(__GNUC__) && (__GNUC__ >= 14)
318 #define ___type(...) __typeof_unqual__(___arrow(__VA_ARGS__))
319 #else
320 #define ___type(...) typeof(___arrow(__VA_ARGS__))
321 #endif
322 
323 #define ___read(read_fn, dst, src_type, src, accessor)			    \
324 	read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor)
325 
326 /* "recursively" read a sequence of inner pointers using local __t var */
327 #define ___rd_first(fn, src, a) ___read(fn, &__t, ___type(src), src, a);
328 #define ___rd_last(fn, ...)						    \
329 	___read(fn, &__t, ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__));
330 #define ___rd_p1(fn, ...) const void *__t; ___rd_first(fn, __VA_ARGS__)
331 #define ___rd_p2(fn, ...) ___rd_p1(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
332 #define ___rd_p3(fn, ...) ___rd_p2(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
333 #define ___rd_p4(fn, ...) ___rd_p3(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
334 #define ___rd_p5(fn, ...) ___rd_p4(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
335 #define ___rd_p6(fn, ...) ___rd_p5(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
336 #define ___rd_p7(fn, ...) ___rd_p6(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
337 #define ___rd_p8(fn, ...) ___rd_p7(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
338 #define ___rd_p9(fn, ...) ___rd_p8(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
339 #define ___read_ptrs(fn, src, ...)					    \
340 	___apply(___rd_p, ___narg(__VA_ARGS__))(fn, src, __VA_ARGS__)
341 
342 #define ___core_read0(fn, fn_ptr, dst, src, a)				    \
343 	___read(fn, dst, ___type(src), src, a);
344 #define ___core_readN(fn, fn_ptr, dst, src, ...)			    \
345 	___read_ptrs(fn_ptr, src, ___nolast(__VA_ARGS__))		    \
346 	___read(fn, dst, ___type(src, ___nolast(__VA_ARGS__)), __t,	    \
347 		___last(__VA_ARGS__));
348 #define ___core_read(fn, fn_ptr, dst, src, a, ...)			    \
349 	___apply(___core_read, ___empty(__VA_ARGS__))(fn, fn_ptr, dst,	    \
350 						      src, a, ##__VA_ARGS__)
351 
352 /*
353  * BPF_CORE_READ_INTO() is a more performance-conscious variant of
354  * BPF_CORE_READ(), in which final field is read into user-provided storage.
355  * See BPF_CORE_READ() below for more details on general usage.
356  */
357 #define BPF_CORE_READ_INTO(dst, src, a, ...) ({				    \
358 	___core_read(bpf_core_read, bpf_core_read,			    \
359 		     dst, (src), a, ##__VA_ARGS__)			    \
360 })
361 
362 /*
363  * Variant of BPF_CORE_READ_INTO() for reading from user-space memory.
364  *
365  * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use.
366  */
367 #define BPF_CORE_READ_USER_INTO(dst, src, a, ...) ({			    \
368 	___core_read(bpf_core_read_user, bpf_core_read_user,		    \
369 		     dst, (src), a, ##__VA_ARGS__)			    \
370 })
371 
372 /* Non-CO-RE variant of BPF_CORE_READ_INTO() */
373 #define BPF_PROBE_READ_INTO(dst, src, a, ...) ({			    \
374 	___core_read(bpf_probe_read_kernel, bpf_probe_read_kernel,	    \
375 		     dst, (src), a, ##__VA_ARGS__)			    \
376 })
377 
378 /* Non-CO-RE variant of BPF_CORE_READ_USER_INTO().
379  *
380  * As no CO-RE relocations are emitted, source types can be arbitrary and are
381  * not restricted to kernel types only.
382  */
383 #define BPF_PROBE_READ_USER_INTO(dst, src, a, ...) ({			    \
384 	___core_read(bpf_probe_read_user, bpf_probe_read_user,		    \
385 		     dst, (src), a, ##__VA_ARGS__)			    \
386 })
387 
388 /*
389  * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as
390  * BPF_CORE_READ() for intermediate pointers, but then executes (and returns
391  * corresponding error code) bpf_core_read_str() for final string read.
392  */
393 #define BPF_CORE_READ_STR_INTO(dst, src, a, ...) ({			    \
394 	___core_read(bpf_core_read_str, bpf_core_read,			    \
395 		     dst, (src), a, ##__VA_ARGS__)			    \
396 })
397 
398 /*
399  * Variant of BPF_CORE_READ_STR_INTO() for reading from user-space memory.
400  *
401  * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use.
402  */
403 #define BPF_CORE_READ_USER_STR_INTO(dst, src, a, ...) ({		    \
404 	___core_read(bpf_core_read_user_str, bpf_core_read_user,	    \
405 		     dst, (src), a, ##__VA_ARGS__)			    \
406 })
407 
408 /* Non-CO-RE variant of BPF_CORE_READ_STR_INTO() */
409 #define BPF_PROBE_READ_STR_INTO(dst, src, a, ...) ({			    \
410 	___core_read(bpf_probe_read_kernel_str, bpf_probe_read_kernel,	    \
411 		     dst, (src), a, ##__VA_ARGS__)			    \
412 })
413 
414 /*
415  * Non-CO-RE variant of BPF_CORE_READ_USER_STR_INTO().
416  *
417  * As no CO-RE relocations are emitted, source types can be arbitrary and are
418  * not restricted to kernel types only.
419  */
420 #define BPF_PROBE_READ_USER_STR_INTO(dst, src, a, ...) ({		    \
421 	___core_read(bpf_probe_read_user_str, bpf_probe_read_user,	    \
422 		     dst, (src), a, ##__VA_ARGS__)			    \
423 })
424 
425 /*
426  * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially
427  * when there are few pointer chasing steps.
428  * E.g., what in non-BPF world (or in BPF w/ BCC) would be something like:
429  *	int x = s->a.b.c->d.e->f->g;
430  * can be succinctly achieved using BPF_CORE_READ as:
431  *	int x = BPF_CORE_READ(s, a.b.c, d.e, f, g);
432  *
433  * BPF_CORE_READ will decompose above statement into 4 bpf_core_read (BPF
434  * CO-RE relocatable bpf_probe_read_kernel() wrapper) calls, logically
435  * equivalent to:
436  * 1. const void *__t = s->a.b.c;
437  * 2. __t = __t->d.e;
438  * 3. __t = __t->f;
439  * 4. return __t->g;
440  *
441  * Equivalence is logical, because there is a heavy type casting/preservation
442  * involved, as well as all the reads are happening through
443  * bpf_probe_read_kernel() calls using __builtin_preserve_access_index() to
444  * emit CO-RE relocations.
445  *
446  * N.B. Only up to 9 "field accessors" are supported, which should be more
447  * than enough for any practical purpose.
448  */
449 #define BPF_CORE_READ(src, a, ...) ({					    \
450 	___type((src), a, ##__VA_ARGS__) __r;				    \
451 	BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__);		    \
452 	__r;								    \
453 })
454 
455 /*
456  * Variant of BPF_CORE_READ() for reading from user-space memory.
457  *
458  * NOTE: all the source types involved are still *kernel types* and need to
459  * exist in kernel (or kernel module) BTF, otherwise CO-RE relocation will
460  * fail. Custom user types are not relocatable with CO-RE.
461  * The typical situation in which BPF_CORE_READ_USER() might be used is to
462  * read kernel UAPI types from the user-space memory passed in as a syscall
463  * input argument.
464  */
465 #define BPF_CORE_READ_USER(src, a, ...) ({				    \
466 	___type((src), a, ##__VA_ARGS__) __r;				    \
467 	BPF_CORE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__);		    \
468 	__r;								    \
469 })
470 
471 /* Non-CO-RE variant of BPF_CORE_READ() */
472 #define BPF_PROBE_READ(src, a, ...) ({					    \
473 	___type((src), a, ##__VA_ARGS__) __r;				    \
474 	BPF_PROBE_READ_INTO(&__r, (src), a, ##__VA_ARGS__);		    \
475 	__r;								    \
476 })
477 
478 /*
479  * Non-CO-RE variant of BPF_CORE_READ_USER().
480  *
481  * As no CO-RE relocations are emitted, source types can be arbitrary and are
482  * not restricted to kernel types only.
483  */
484 #define BPF_PROBE_READ_USER(src, a, ...) ({				    \
485 	___type((src), a, ##__VA_ARGS__) __r;				    \
486 	BPF_PROBE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__);	    \
487 	__r;								    \
488 })
489 
490 #endif
491 
492