2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
5 * David Chisnall <theraven@FreeBSD.org>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
35 #include <sys/cdefs.h>
36 #include <sys/_types.h>
38 #if __has_extension(c_atomic) || __has_extension(cxx_atomic)
39 #define __CLANG_ATOMICS
40 #elif __GNUC_PREREQ__(4, 7)
41 #define __GNUC_ATOMICS
42 #elif defined(__GNUC__)
43 #define __SYNC_ATOMICS
45 #error "stdatomic.h does not support your compiler"
49 * 7.17.1 Atomic lock-free macros.
52 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
53 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
55 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
56 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
58 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
59 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
61 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
62 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
64 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
65 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
67 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
68 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
70 #ifdef __GCC_ATOMIC_INT_LOCK_FREE
71 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
73 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
74 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
76 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
77 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
79 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
80 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
84 * 7.17.2 Initialization.
87 #if defined(__CLANG_ATOMICS)
88 #define ATOMIC_VAR_INIT(value) (value)
89 #define atomic_init(obj, value) __c11_atomic_init(obj, value)
91 #define ATOMIC_VAR_INIT(value) { .__val = (value) }
92 #define atomic_init(obj, value) ((void)((obj)->__val = (value)))
96 * Clang and recent GCC both provide predefined macros for the memory
97 * orderings. If we are using a compiler that doesn't define them, use the
98 * clang values - these will be ignored in the fallback path.
101 #ifndef __ATOMIC_RELAXED
102 #define __ATOMIC_RELAXED 0
104 #ifndef __ATOMIC_CONSUME
105 #define __ATOMIC_CONSUME 1
107 #ifndef __ATOMIC_ACQUIRE
108 #define __ATOMIC_ACQUIRE 2
110 #ifndef __ATOMIC_RELEASE
111 #define __ATOMIC_RELEASE 3
113 #ifndef __ATOMIC_ACQ_REL
114 #define __ATOMIC_ACQ_REL 4
116 #ifndef __ATOMIC_SEQ_CST
117 #define __ATOMIC_SEQ_CST 5
121 * 7.17.3 Order and consistency.
123 * The memory_order_* constants that denote the barrier behaviour of the
128 memory_order_relaxed = __ATOMIC_RELAXED,
129 memory_order_consume = __ATOMIC_CONSUME,
130 memory_order_acquire = __ATOMIC_ACQUIRE,
131 memory_order_release = __ATOMIC_RELEASE,
132 memory_order_acq_rel = __ATOMIC_ACQ_REL,
133 memory_order_seq_cst = __ATOMIC_SEQ_CST
141 atomic_thread_fence(memory_order __order __unused)
144 #ifdef __CLANG_ATOMICS
145 __c11_atomic_thread_fence(__order);
146 #elif defined(__GNUC_ATOMICS)
147 __atomic_thread_fence(__order);
149 __sync_synchronize();
154 atomic_signal_fence(memory_order __order __unused)
157 #ifdef __CLANG_ATOMICS
158 __c11_atomic_signal_fence(__order);
159 #elif defined(__GNUC_ATOMICS)
160 __atomic_signal_fence(__order);
162 __asm volatile ("" ::: "memory");
167 * 7.17.5 Lock-free property.
171 /* Atomics in kernelspace are always lock-free. */
172 #define atomic_is_lock_free(obj) \
173 ((void)(obj), (_Bool)1)
174 #elif defined(__CLANG_ATOMICS)
175 #define atomic_is_lock_free(obj) \
176 __atomic_is_lock_free(sizeof(*(obj)), obj)
177 #elif defined(__GNUC_ATOMICS)
178 #define atomic_is_lock_free(obj) \
179 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
181 #define atomic_is_lock_free(obj) \
182 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
186 * 7.17.6 Atomic integer types.
189 typedef _Atomic(_Bool) atomic_bool;
190 typedef _Atomic(char) atomic_char;
191 typedef _Atomic(signed char) atomic_schar;
192 typedef _Atomic(unsigned char) atomic_uchar;
193 typedef _Atomic(short) atomic_short;
194 typedef _Atomic(unsigned short) atomic_ushort;
195 typedef _Atomic(int) atomic_int;
196 typedef _Atomic(unsigned int) atomic_uint;
197 typedef _Atomic(long) atomic_long;
198 typedef _Atomic(unsigned long) atomic_ulong;
199 typedef _Atomic(long long) atomic_llong;
200 typedef _Atomic(unsigned long long) atomic_ullong;
201 typedef _Atomic(__char16_t) atomic_char16_t;
202 typedef _Atomic(__char32_t) atomic_char32_t;
203 typedef _Atomic(___wchar_t) atomic_wchar_t;
204 typedef _Atomic(__int_least8_t) atomic_int_least8_t;
205 typedef _Atomic(__uint_least8_t) atomic_uint_least8_t;
206 typedef _Atomic(__int_least16_t) atomic_int_least16_t;
207 typedef _Atomic(__uint_least16_t) atomic_uint_least16_t;
208 typedef _Atomic(__int_least32_t) atomic_int_least32_t;
209 typedef _Atomic(__uint_least32_t) atomic_uint_least32_t;
210 typedef _Atomic(__int_least64_t) atomic_int_least64_t;
211 typedef _Atomic(__uint_least64_t) atomic_uint_least64_t;
212 typedef _Atomic(__int_fast8_t) atomic_int_fast8_t;
213 typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t;
214 typedef _Atomic(__int_fast16_t) atomic_int_fast16_t;
215 typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t;
216 typedef _Atomic(__int_fast32_t) atomic_int_fast32_t;
217 typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t;
218 typedef _Atomic(__int_fast64_t) atomic_int_fast64_t;
219 typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t;
220 typedef _Atomic(__intptr_t) atomic_intptr_t;
221 typedef _Atomic(__uintptr_t) atomic_uintptr_t;
222 typedef _Atomic(__size_t) atomic_size_t;
223 typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t;
224 typedef _Atomic(__intmax_t) atomic_intmax_t;
225 typedef _Atomic(__uintmax_t) atomic_uintmax_t;
228 * 7.17.7 Operations on atomic types.
232 * Compiler-specific operations.
235 #if defined(__CLANG_ATOMICS)
236 #define atomic_compare_exchange_strong_explicit(object, expected, \
237 desired, success, failure) \
238 __c11_atomic_compare_exchange_strong(object, expected, desired, \
240 #define atomic_compare_exchange_weak_explicit(object, expected, \
241 desired, success, failure) \
242 __c11_atomic_compare_exchange_weak(object, expected, desired, \
244 #define atomic_exchange_explicit(object, desired, order) \
245 __c11_atomic_exchange(object, desired, order)
246 #define atomic_fetch_add_explicit(object, operand, order) \
247 __c11_atomic_fetch_add(object, operand, order)
248 #define atomic_fetch_and_explicit(object, operand, order) \
249 __c11_atomic_fetch_and(object, operand, order)
250 #define atomic_fetch_or_explicit(object, operand, order) \
251 __c11_atomic_fetch_or(object, operand, order)
252 #define atomic_fetch_sub_explicit(object, operand, order) \
253 __c11_atomic_fetch_sub(object, operand, order)
254 #define atomic_fetch_xor_explicit(object, operand, order) \
255 __c11_atomic_fetch_xor(object, operand, order)
256 #define atomic_load_explicit(object, order) \
257 __c11_atomic_load(object, order)
258 #define atomic_store_explicit(object, desired, order) \
259 __c11_atomic_store(object, desired, order)
260 #elif defined(__GNUC_ATOMICS)
261 #define atomic_compare_exchange_strong_explicit(object, expected, \
262 desired, success, failure) \
263 __atomic_compare_exchange_n(&(object)->__val, expected, \
264 desired, 0, success, failure)
265 #define atomic_compare_exchange_weak_explicit(object, expected, \
266 desired, success, failure) \
267 __atomic_compare_exchange_n(&(object)->__val, expected, \
268 desired, 1, success, failure)
269 #define atomic_exchange_explicit(object, desired, order) \
270 __atomic_exchange_n(&(object)->__val, desired, order)
271 #define atomic_fetch_add_explicit(object, operand, order) \
272 __atomic_fetch_add(&(object)->__val, operand, order)
273 #define atomic_fetch_and_explicit(object, operand, order) \
274 __atomic_fetch_and(&(object)->__val, operand, order)
275 #define atomic_fetch_or_explicit(object, operand, order) \
276 __atomic_fetch_or(&(object)->__val, operand, order)
277 #define atomic_fetch_sub_explicit(object, operand, order) \
278 __atomic_fetch_sub(&(object)->__val, operand, order)
279 #define atomic_fetch_xor_explicit(object, operand, order) \
280 __atomic_fetch_xor(&(object)->__val, operand, order)
281 #define atomic_load_explicit(object, order) \
282 __atomic_load_n(&(object)->__val, order)
283 #define atomic_store_explicit(object, desired, order) \
284 __atomic_store_n(&(object)->__val, desired, order)
286 #define __atomic_apply_stride(object, operand) \
287 (((__typeof__((object)->__val))0) + (operand))
288 #define atomic_compare_exchange_strong_explicit(object, expected, \
289 desired, success, failure) __extension__ ({ \
290 __typeof__(expected) __ep = (expected); \
291 __typeof__(*__ep) __e = *__ep; \
292 (void)(success); (void)(failure); \
293 (_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \
294 __e, desired)) == __e); \
296 #define atomic_compare_exchange_weak_explicit(object, expected, \
297 desired, success, failure) \
298 atomic_compare_exchange_strong_explicit(object, expected, \
299 desired, success, failure)
300 #if __has_builtin(__sync_swap)
301 /* Clang provides a full-barrier atomic exchange - use it if available. */
302 #define atomic_exchange_explicit(object, desired, order) \
303 ((void)(order), __sync_swap(&(object)->__val, desired))
306 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
307 * practice it is usually a full barrier) so we need an explicit barrier before
310 #define atomic_exchange_explicit(object, desired, order) \
312 __typeof__(object) __o = (object); \
313 __typeof__(desired) __d = (desired); \
315 __sync_synchronize(); \
316 __sync_lock_test_and_set(&(__o)->__val, __d); \
319 #define atomic_fetch_add_explicit(object, operand, order) \
320 ((void)(order), __sync_fetch_and_add(&(object)->__val, \
321 __atomic_apply_stride(object, operand)))
322 #define atomic_fetch_and_explicit(object, operand, order) \
323 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
324 #define atomic_fetch_or_explicit(object, operand, order) \
325 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
326 #define atomic_fetch_sub_explicit(object, operand, order) \
327 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \
328 __atomic_apply_stride(object, operand)))
329 #define atomic_fetch_xor_explicit(object, operand, order) \
330 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
331 #define atomic_load_explicit(object, order) \
332 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
333 #define atomic_store_explicit(object, desired, order) \
334 ((void)atomic_exchange_explicit(object, desired, order))
338 * Convenience functions.
340 * Don't provide these in kernel space. In kernel space, we should be
341 * disciplined enough to always provide explicit barriers.
345 #define atomic_compare_exchange_strong(object, expected, desired) \
346 atomic_compare_exchange_strong_explicit(object, expected, \
347 desired, memory_order_seq_cst, memory_order_seq_cst)
348 #define atomic_compare_exchange_weak(object, expected, desired) \
349 atomic_compare_exchange_weak_explicit(object, expected, \
350 desired, memory_order_seq_cst, memory_order_seq_cst)
351 #define atomic_exchange(object, desired) \
352 atomic_exchange_explicit(object, desired, memory_order_seq_cst)
353 #define atomic_fetch_add(object, operand) \
354 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
355 #define atomic_fetch_and(object, operand) \
356 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
357 #define atomic_fetch_or(object, operand) \
358 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
359 #define atomic_fetch_sub(object, operand) \
360 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
361 #define atomic_fetch_xor(object, operand) \
362 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
363 #define atomic_load(object) \
364 atomic_load_explicit(object, memory_order_seq_cst)
365 #define atomic_store(object, desired) \
366 atomic_store_explicit(object, desired, memory_order_seq_cst)
367 #endif /* !_KERNEL */
370 * 7.17.8 Atomic flag type and operations.
372 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some
373 * kind of compiler built-in type we could use?
380 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) }
382 static __inline _Bool
383 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
384 memory_order __order)
386 return (atomic_exchange_explicit(&__object->__flag, 1, __order));
390 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
393 atomic_store_explicit(&__object->__flag, 0, __order);
397 static __inline _Bool
398 atomic_flag_test_and_set(volatile atomic_flag *__object)
401 return (atomic_flag_test_and_set_explicit(__object,
402 memory_order_seq_cst));
406 atomic_flag_clear(volatile atomic_flag *__object)
409 atomic_flag_clear_explicit(__object, memory_order_seq_cst);
411 #endif /* !_KERNEL */
413 #endif /* !_STDATOMIC_H_ */