1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
5 * David Chisnall <theraven@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #ifndef __STDC_VERSION_STDATOMIC_H__
31 #define __STDC_VERSION_STDATOMIC_H__ 202311L
32
33 #include <sys/cdefs.h>
34 #include <sys/_types.h>
35
36 #if (__has_extension(c_atomic) || __has_extension(cxx_atomic)) && \
37 defined(__clang__)
38 #define __CLANG_ATOMICS
39 #elif __GNUC_PREREQ__(4, 7)
40 #define __GNUC_ATOMICS
41 #elif defined(__GNUC__)
42 #define __SYNC_ATOMICS
43 #else
44 #error "stdatomic.h does not support your compiler"
45 #endif
46
47 /*
48 * 7.17.1 Atomic lock-free macros.
49 */
50
51 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
52 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
53 #endif
54 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
55 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
56 #endif
57 #if __ISO_C_VISIBLE >= 2023 && defined(__GCC_ATOMIC_CHAR8_T_LOCK_FREE)
58 #define ATOMIC_CHAR8_T_LOCK_FREE __GCC_ATOMIC_CHAR8_T_LOCK_FREE
59 #endif
60 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
61 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
62 #endif
63 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
64 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
65 #endif
66 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
67 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
68 #endif
69 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
70 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
71 #endif
72 #ifdef __GCC_ATOMIC_INT_LOCK_FREE
73 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
74 #endif
75 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
76 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
77 #endif
78 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
79 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
80 #endif
81 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
82 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
83 #endif
84
85 /*
86 * 7.17.2 Initialization.
87 */
88
89 #if __BSD_VISIBLE || __ISO_C_VISIBLE < 2023 || defined(__cplusplus)
90 #if defined(__CLANG_ATOMICS)
91 #define ATOMIC_VAR_INIT(value) (value)
92 #else
93 #define ATOMIC_VAR_INIT(value) { .__val = (value) }
94 #endif
95 #endif
96
97 #if defined(__CLANG_ATOMICS)
98 #define atomic_init(obj, value) __c11_atomic_init(obj, value)
99 #elif defined(__GNUC_ATOMICS)
100 #define atomic_init(obj, value) atomic_store_explicit(obj, \
101 value, __ATOMIC_RELAXED)
102 #else
103 #define atomic_init(obj, value) ((void)((obj)->__val = (value)))
104 #endif
105
106 /*
107 * 7.17.3 Order and consistency.
108 *
109 * The memory_order_* constants that denote the barrier behaviour of the
110 * atomic operations.
111 */
112
113 #ifndef __ATOMIC_RELAXED
114 #define __ATOMIC_RELAXED 0
115 #endif
116 #ifndef __ATOMIC_CONSUME
117 #define __ATOMIC_CONSUME 1
118 #endif
119 #ifndef __ATOMIC_ACQUIRE
120 #define __ATOMIC_ACQUIRE 2
121 #endif
122 #ifndef __ATOMIC_RELEASE
123 #define __ATOMIC_RELEASE 3
124 #endif
125 #ifndef __ATOMIC_ACQ_REL
126 #define __ATOMIC_ACQ_REL 4
127 #endif
128 #ifndef __ATOMIC_SEQ_CST
129 #define __ATOMIC_SEQ_CST 5
130 #endif
131
132 typedef enum {
133 memory_order_relaxed = __ATOMIC_RELAXED,
134 memory_order_consume = __ATOMIC_CONSUME,
135 memory_order_acquire = __ATOMIC_ACQUIRE,
136 memory_order_release = __ATOMIC_RELEASE,
137 memory_order_acq_rel = __ATOMIC_ACQ_REL,
138 memory_order_seq_cst = __ATOMIC_SEQ_CST
139 } memory_order;
140
141 #define kill_dependency(y) (y)
142
143 /*
144 * 7.17.4 Fences.
145 */
146
147 static __inline void
atomic_thread_fence(memory_order __order __unused)148 atomic_thread_fence(memory_order __order __unused)
149 {
150
151 #ifdef __CLANG_ATOMICS
152 __c11_atomic_thread_fence(__order);
153 #elif defined(__GNUC_ATOMICS)
154 __atomic_thread_fence(__order);
155 #else
156 __sync_synchronize();
157 #endif
158 }
159
160 static __inline void
atomic_signal_fence(memory_order __order __unused)161 atomic_signal_fence(memory_order __order __unused)
162 {
163
164 #ifdef __CLANG_ATOMICS
165 __c11_atomic_signal_fence(__order);
166 #elif defined(__GNUC_ATOMICS)
167 __atomic_signal_fence(__order);
168 #else
169 __asm volatile ("" ::: "memory");
170 #endif
171 }
172
173 #if defined(__cplusplus) && !defined(_Bool)
174 #define _Bool bool
175 #define __bool_locally_defined
176 #endif
177
178 /*
179 * 7.17.5 Lock-free property.
180 */
181
182 #if defined(_KERNEL)
183 /* Atomics in kernelspace are always lock-free. */
184 #define atomic_is_lock_free(obj) \
185 ((void)(obj), (_Bool)1)
186 #elif defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS)
187 #define atomic_is_lock_free(obj) \
188 __atomic_is_lock_free(sizeof(*(obj)), obj)
189 #else
190 #define atomic_is_lock_free(obj) \
191 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
192 #endif
193
194 /*
195 * 7.17.6 Atomic integer types.
196 */
197
198 typedef _Atomic(_Bool) atomic_bool;
199 typedef _Atomic(char) atomic_char;
200 typedef _Atomic(signed char) atomic_schar;
201 typedef _Atomic(unsigned char) atomic_uchar;
202 typedef _Atomic(short) atomic_short;
203 typedef _Atomic(unsigned short) atomic_ushort;
204 typedef _Atomic(int) atomic_int;
205 typedef _Atomic(unsigned int) atomic_uint;
206 typedef _Atomic(long) atomic_long;
207 typedef _Atomic(unsigned long) atomic_ulong;
208 typedef _Atomic(long long) atomic_llong;
209 typedef _Atomic(unsigned long long) atomic_ullong;
210 #if __ISO_C_VISIBLE >= 2023
211 typedef _Atomic(unsigned char) atomic_char8_t;
212 #endif
213 typedef _Atomic(__char16_t) atomic_char16_t;
214 typedef _Atomic(__char32_t) atomic_char32_t;
215 typedef _Atomic(___wchar_t) atomic_wchar_t;
216 typedef _Atomic(__int_least8_t) atomic_int_least8_t;
217 typedef _Atomic(__uint_least8_t) atomic_uint_least8_t;
218 typedef _Atomic(__int_least16_t) atomic_int_least16_t;
219 typedef _Atomic(__uint_least16_t) atomic_uint_least16_t;
220 typedef _Atomic(__int_least32_t) atomic_int_least32_t;
221 typedef _Atomic(__uint_least32_t) atomic_uint_least32_t;
222 typedef _Atomic(__int_least64_t) atomic_int_least64_t;
223 typedef _Atomic(__uint_least64_t) atomic_uint_least64_t;
224 typedef _Atomic(__int_fast8_t) atomic_int_fast8_t;
225 typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t;
226 typedef _Atomic(__int_fast16_t) atomic_int_fast16_t;
227 typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t;
228 typedef _Atomic(__int_fast32_t) atomic_int_fast32_t;
229 typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t;
230 typedef _Atomic(__int_fast64_t) atomic_int_fast64_t;
231 typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t;
232 typedef _Atomic(__intptr_t) atomic_intptr_t;
233 typedef _Atomic(__uintptr_t) atomic_uintptr_t;
234 typedef _Atomic(__size_t) atomic_size_t;
235 typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t;
236 typedef _Atomic(__intmax_t) atomic_intmax_t;
237 typedef _Atomic(__uintmax_t) atomic_uintmax_t;
238
239 /*
240 * 7.17.7 Operations on atomic types.
241 */
242
243 /*
244 * Compiler-specific operations.
245 */
246
247 #if defined(__CLANG_ATOMICS)
248 #define atomic_store_explicit(object, desired, order) \
249 __c11_atomic_store(object, desired, order)
250 #define atomic_load_explicit(object, order) \
251 __c11_atomic_load(object, order)
252 #define atomic_exchange_explicit(object, desired, order) \
253 __c11_atomic_exchange(object, desired, order)
254 #define atomic_compare_exchange_strong_explicit(object, expected, \
255 desired, success, failure) \
256 __c11_atomic_compare_exchange_strong(object, expected, desired, \
257 success, failure)
258 #define atomic_compare_exchange_weak_explicit(object, expected, \
259 desired, success, failure) \
260 __c11_atomic_compare_exchange_weak(object, expected, desired, \
261 success, failure)
262 #define atomic_fetch_add_explicit(object, operand, order) \
263 __c11_atomic_fetch_add(object, operand, order)
264 #define atomic_fetch_sub_explicit(object, operand, order) \
265 __c11_atomic_fetch_sub(object, operand, order)
266 #define atomic_fetch_or_explicit(object, operand, order) \
267 __c11_atomic_fetch_or(object, operand, order)
268 #define atomic_fetch_xor_explicit(object, operand, order) \
269 __c11_atomic_fetch_xor(object, operand, order)
270 #define atomic_fetch_and_explicit(object, operand, order) \
271 __c11_atomic_fetch_and(object, operand, order)
272 #elif defined(__GNUC_ATOMICS)
273 #define __atomic_apply_stride(object, operand) \
274 (((__typeof__(*(object)))0) + (operand))
275 #define atomic_store_explicit(object, desired, order) \
276 __atomic_store_n(object, desired, order)
277 #define atomic_load_explicit(object, order) \
278 __atomic_load_n(object, order)
279 #define atomic_exchange_explicit(object, desired, order) \
280 __atomic_exchange_n(object, desired, order)
281 #define atomic_compare_exchange_strong_explicit(object, expected, \
282 desired, success, failure) \
283 __atomic_compare_exchange_n(object, expected, \
284 desired, 0, success, failure)
285 #define atomic_compare_exchange_weak_explicit(object, expected, \
286 desired, success, failure) \
287 __atomic_compare_exchange_n(object, expected, \
288 desired, 1, success, failure)
289 #define atomic_fetch_add_explicit(object, operand, order) \
290 __atomic_fetch_add(object, \
291 __atomic_apply_stride(object, operand), order)
292 #define atomic_fetch_sub_explicit(object, operand, order) \
293 __atomic_fetch_sub(object, \
294 __atomic_apply_stride(object, operand), order)
295 #define atomic_fetch_or_explicit(object, operand, order) \
296 __atomic_fetch_or(object, operand, order)
297 #define atomic_fetch_xor_explicit(object, operand, order) \
298 __atomic_fetch_xor(object, operand, order)
299 #define atomic_fetch_and_explicit(object, operand, order) \
300 __atomic_fetch_and(object, operand, order)
301 #else
302 #define __atomic_apply_stride(object, operand) \
303 (((__typeof__((object)->__val))0) + (operand))
304 #define atomic_store_explicit(object, desired, order) \
305 ((void)atomic_exchange_explicit(object, desired, order))
306 #define atomic_load_explicit(object, order) \
307 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
308 #if __has_builtin(__sync_swap)
309 /* Clang provides a full-barrier atomic exchange - use it if available. */
310 #define atomic_exchange_explicit(object, desired, order) \
311 ((void)(order), __sync_swap(&(object)->__val, desired))
312 #else
313 /*
314 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
315 * practice it is usually a full barrier) so we need an explicit barrier before
316 * it.
317 */
318 #define atomic_exchange_explicit(object, desired, order) \
319 __extension__ ({ \
320 __typeof__(object) __o = (object); \
321 __typeof__(desired) __d = (desired); \
322 (void)(order); \
323 __sync_synchronize(); \
324 __sync_lock_test_and_set(&(__o)->__val, __d); \
325 })
326 #define atomic_compare_exchange_strong_explicit(object, expected, \
327 desired, success, failure) __extension__ ({ \
328 __typeof__(expected) __ep = (expected); \
329 __typeof__(*__ep) __e = *__ep; \
330 (void)(success); (void)(failure); \
331 (_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \
332 __e, desired)) == __e); \
333 })
334 #define atomic_compare_exchange_weak_explicit(object, expected, \
335 desired, success, failure) \
336 atomic_compare_exchange_strong_explicit(object, expected, \
337 desired, success, failure)
338 #endif
339 #define atomic_fetch_add_explicit(object, operand, order) \
340 ((void)(order), __sync_fetch_and_add(&(object)->__val, \
341 __atomic_apply_stride(object, operand)))
342 #define atomic_fetch_sub_explicit(object, operand, order) \
343 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \
344 __atomic_apply_stride(object, operand)))
345 #define atomic_fetch_or_explicit(object, operand, order) \
346 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
347 #define atomic_fetch_xor_explicit(object, operand, order) \
348 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
349 #define atomic_fetch_and_explicit(object, operand, order) \
350 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
351 #endif
352
353 /*
354 * Convenience functions.
355 *
356 * Don't provide these in kernel space. In kernel space, we should be
357 * disciplined enough to always provide explicit barriers.
358 */
359
360 #ifndef _KERNEL
361 #define atomic_store(object, desired) \
362 atomic_store_explicit(object, desired, memory_order_seq_cst)
363 #define atomic_load(object) \
364 atomic_load_explicit(object, memory_order_seq_cst)
365 #define atomic_exchange(object, desired) \
366 atomic_exchange_explicit(object, desired, memory_order_seq_cst)
367 #define atomic_compare_exchange_strong(object, expected, desired) \
368 atomic_compare_exchange_strong_explicit(object, expected, \
369 desired, memory_order_seq_cst, memory_order_seq_cst)
370 #define atomic_compare_exchange_weak(object, expected, desired) \
371 atomic_compare_exchange_weak_explicit(object, expected, \
372 desired, memory_order_seq_cst, memory_order_seq_cst)
373 #define atomic_fetch_add(object, operand) \
374 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
375 #define atomic_fetch_sub(object, operand) \
376 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
377 #define atomic_fetch_or(object, operand) \
378 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
379 #define atomic_fetch_xor(object, operand) \
380 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
381 #define atomic_fetch_and(object, operand) \
382 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
383 #endif /* !_KERNEL */
384
385 /*
386 * 7.17.8 Atomic flag type and operations.
387 */
388
389 typedef struct {
390 #if ATOMIC_BOOL_LOCK_FREE == 2
391 atomic_bool __flag;
392 #elif ATOMIC_CHAR_LOCK_FREE == 2
393 atomic_uchar __flag;
394 #else
395 #error "atomic_flag is required to be lock-free"
396 #endif
397 } atomic_flag;
398 #if __ISO_C_VISIBLE < 2023
399 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) }
400 #else
401 #define ATOMIC_FLAG_INIT { 0 }
402 #endif
403
404 static __inline _Bool
atomic_flag_test_and_set_explicit(volatile atomic_flag * __object,memory_order __order)405 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
406 memory_order __order)
407 {
408
409 return (atomic_exchange_explicit(&__object->__flag, 1, __order) != 0);
410 }
411
412 static __inline void
atomic_flag_clear_explicit(volatile atomic_flag * __object,memory_order __order)413 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
414 {
415
416 atomic_store_explicit(&__object->__flag, 0, __order);
417 }
418
419 #ifndef _KERNEL
420 static __inline _Bool
atomic_flag_test_and_set(volatile atomic_flag * __object)421 atomic_flag_test_and_set(volatile atomic_flag *__object)
422 {
423
424 return (atomic_flag_test_and_set_explicit(__object,
425 memory_order_seq_cst));
426 }
427
428 static __inline void
atomic_flag_clear(volatile atomic_flag * __object)429 atomic_flag_clear(volatile atomic_flag *__object)
430 {
431
432 atomic_flag_clear_explicit(__object, memory_order_seq_cst);
433 }
434 #endif /* !_KERNEL */
435
436 #ifdef __bool_locally_defined
437 #undef _Bool
438 #undef __bool_locally_defined
439 #endif
440
441 #endif /* !__STDC_VERSION_STDATOMIC_H__ */
442