2 * SPDX-License-Identifier: BSD-2-Clause
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
33 #include <sys/cdefs.h>
34 #include <sys/_types.h>
36 #if (__has_extension(c_atomic) || __has_extension(cxx_atomic)) && \
38 #define __CLANG_ATOMICS
39 #elif __GNUC_PREREQ__(4, 7)
40 #define __GNUC_ATOMICS
41 #elif defined(__GNUC__)
42 #define __SYNC_ATOMICS
44 #error "stdatomic.h does not support your compiler"
48 * 7.17.1 Atomic lock-free macros.
51 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
52 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
54 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
55 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
57 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
58 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
60 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
61 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
63 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
64 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
66 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
67 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
69 #ifdef __GCC_ATOMIC_INT_LOCK_FREE
70 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
72 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
73 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
75 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
76 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
78 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
79 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
83 * 7.17.2 Initialization.
86 #if defined(__CLANG_ATOMICS)
87 #define ATOMIC_VAR_INIT(value) (value)
88 #define atomic_init(obj, value) __c11_atomic_init(obj, value)
90 #define ATOMIC_VAR_INIT(value) { .__val = (value) }
91 #define atomic_init(obj, value) ((void)((obj)->__val = (value)))
95 * Clang and recent GCC both provide predefined macros for the memory
96 * orderings. If we are using a compiler that doesn't define them, use the
97 * clang values - these will be ignored in the fallback path.
100 #ifndef __ATOMIC_RELAXED
101 #define __ATOMIC_RELAXED 0
103 #ifndef __ATOMIC_CONSUME
104 #define __ATOMIC_CONSUME 1
106 #ifndef __ATOMIC_ACQUIRE
107 #define __ATOMIC_ACQUIRE 2
109 #ifndef __ATOMIC_RELEASE
110 #define __ATOMIC_RELEASE 3
112 #ifndef __ATOMIC_ACQ_REL
113 #define __ATOMIC_ACQ_REL 4
115 #ifndef __ATOMIC_SEQ_CST
116 #define __ATOMIC_SEQ_CST 5
120 * 7.17.3 Order and consistency.
122 * The memory_order_* constants that denote the barrier behaviour of the
127 memory_order_relaxed
= __ATOMIC_RELAXED
,
128 memory_order_consume
= __ATOMIC_CONSUME
,
129 memory_order_acquire
= __ATOMIC_ACQUIRE
,
130 memory_order_release
= __ATOMIC_RELEASE
,
131 memory_order_acq_rel
= __ATOMIC_ACQ_REL
,
132 memory_order_seq_cst
= __ATOMIC_SEQ_CST
140 atomic_thread_fence(memory_order __order __unused
)
143 #ifdef __CLANG_ATOMICS
144 __c11_atomic_thread_fence(__order
);
145 #elif defined(__GNUC_ATOMICS)
146 __atomic_thread_fence(__order
);
148 __sync_synchronize();
153 atomic_signal_fence(memory_order __order __unused
)
156 #ifdef __CLANG_ATOMICS
157 __c11_atomic_signal_fence(__order
);
158 #elif defined(__GNUC_ATOMICS)
159 __atomic_signal_fence(__order
);
161 __asm
volatile ("" ::: "memory");
165 #if defined(__cplusplus) && !defined(_Bool)
167 #define __bool_locally_defined
171 * 7.17.5 Lock-free property.
175 /* Atomics in kernelspace are always lock-free. */
176 #define atomic_is_lock_free(obj) \
177 ((void)(obj), (_Bool)1)
178 #elif defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS)
179 #define atomic_is_lock_free(obj) \
180 __atomic_is_lock_free(sizeof(*(obj)), obj)
182 #define atomic_is_lock_free(obj) \
183 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
187 * 7.17.6 Atomic integer types.
190 typedef _Atomic(_Bool
) atomic_bool
;
191 typedef _Atomic(char) atomic_char
;
192 typedef _Atomic(signed char) atomic_schar
;
193 typedef _Atomic(unsigned char) atomic_uchar
;
194 typedef _Atomic(short) atomic_short
;
195 typedef _Atomic(unsigned short) atomic_ushort
;
196 typedef _Atomic(int) atomic_int
;
197 typedef _Atomic(unsigned int) atomic_uint
;
198 typedef _Atomic(long) atomic_long
;
199 typedef _Atomic(unsigned long) atomic_ulong
;
200 typedef _Atomic(long long) atomic_llong
;
201 typedef _Atomic(unsigned long long) atomic_ullong
;
203 typedef _Atomic(__char16_t
) atomic_char16_t
;
204 typedef _Atomic(__char32_t
) atomic_char32_t
;
206 typedef _Atomic(wchar_t) atomic_wchar_t
;
207 typedef _Atomic(int_least8_t) atomic_int_least8_t
;
208 typedef _Atomic(uint_least8_t) atomic_uint_least8_t
;
209 typedef _Atomic(int_least16_t) atomic_int_least16_t
;
210 typedef _Atomic(uint_least16_t) atomic_uint_least16_t
;
211 typedef _Atomic(int_least32_t) atomic_int_least32_t
;
212 typedef _Atomic(uint_least32_t) atomic_uint_least32_t
;
213 typedef _Atomic(int_least64_t) atomic_int_least64_t
;
214 typedef _Atomic(uint_least64_t) atomic_uint_least64_t
;
215 typedef _Atomic(int_fast8_t) atomic_int_fast8_t
;
216 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t
;
217 typedef _Atomic(int_fast16_t) atomic_int_fast16_t
;
218 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t
;
219 typedef _Atomic(int_fast32_t) atomic_int_fast32_t
;
220 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t
;
221 typedef _Atomic(int_fast64_t) atomic_int_fast64_t
;
222 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t
;
223 typedef _Atomic(intptr_t) atomic_intptr_t
;
224 typedef _Atomic(uintptr_t) atomic_uintptr_t
;
225 typedef _Atomic(size_t) atomic_size_t
;
226 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t
;
227 typedef _Atomic(intmax_t) atomic_intmax_t
;
228 typedef _Atomic(uintmax_t) atomic_uintmax_t
;
231 * 7.17.7 Operations on atomic types.
235 * Compiler-specific operations.
238 #if defined(__CLANG_ATOMICS)
239 #define atomic_compare_exchange_strong_explicit(object, expected, \
240 desired, success, failure) \
241 __c11_atomic_compare_exchange_strong(object, expected, desired, \
243 #define atomic_compare_exchange_weak_explicit(object, expected, \
244 desired, success, failure) \
245 __c11_atomic_compare_exchange_weak(object, expected, desired, \
247 #define atomic_exchange_explicit(object, desired, order) \
248 __c11_atomic_exchange(object, desired, order)
249 #define atomic_fetch_add_explicit(object, operand, order) \
250 __c11_atomic_fetch_add(object, operand, order)
251 #define atomic_fetch_and_explicit(object, operand, order) \
252 __c11_atomic_fetch_and(object, operand, order)
253 #define atomic_fetch_or_explicit(object, operand, order) \
254 __c11_atomic_fetch_or(object, operand, order)
255 #define atomic_fetch_sub_explicit(object, operand, order) \
256 __c11_atomic_fetch_sub(object, operand, order)
257 #define atomic_fetch_xor_explicit(object, operand, order) \
258 __c11_atomic_fetch_xor(object, operand, order)
259 #define atomic_load_explicit(object, order) \
260 __c11_atomic_load(object, order)
261 #define atomic_store_explicit(object, desired, order) \
262 __c11_atomic_store(object, desired, order)
263 #elif defined(__GNUC_ATOMICS)
264 #define atomic_compare_exchange_strong_explicit(object, expected, \
265 desired, success, failure) \
266 __atomic_compare_exchange_n(object, expected, \
267 desired, 0, success, failure)
268 #define atomic_compare_exchange_weak_explicit(object, expected, \
269 desired, success, failure) \
270 __atomic_compare_exchange_n(object, expected, \
271 desired, 1, success, failure)
272 #define atomic_exchange_explicit(object, desired, order) \
273 __atomic_exchange_n(object, desired, order)
274 #define atomic_fetch_add_explicit(object, operand, order) \
275 __atomic_fetch_add(object, operand, order)
276 #define atomic_fetch_and_explicit(object, operand, order) \
277 __atomic_fetch_and(object, operand, order)
278 #define atomic_fetch_or_explicit(object, operand, order) \
279 __atomic_fetch_or(object, operand, order)
280 #define atomic_fetch_sub_explicit(object, operand, order) \
281 __atomic_fetch_sub(object, operand, order)
282 #define atomic_fetch_xor_explicit(object, operand, order) \
283 __atomic_fetch_xor(object, operand, order)
284 #define atomic_load_explicit(object, order) \
285 __atomic_load_n(object, order)
286 #define atomic_store_explicit(object, desired, order) \
287 __atomic_store_n(object, desired, order)
289 #define __atomic_apply_stride(object, operand) \
290 (((__typeof__((object)->__val))0) + (operand))
291 #define atomic_compare_exchange_strong_explicit(object, expected, \
292 desired, success, failure) __extension__ ({ \
293 __typeof__(expected) __ep = (expected); \
294 __typeof__(*__ep) __e = *__ep; \
295 (void)(success); (void)(failure); \
296 (_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \
297 __e, desired)) == __e); \
299 #define atomic_compare_exchange_weak_explicit(object, expected, \
300 desired, success, failure) \
301 atomic_compare_exchange_strong_explicit(object, expected, \
302 desired, success, failure)
303 #if __has_builtin(__sync_swap)
304 /* Clang provides a full-barrier atomic exchange - use it if available. */
305 #define atomic_exchange_explicit(object, desired, order) \
306 ((void)(order), __sync_swap(&(object)->__val, desired))
309 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
310 * practice it is usually a full barrier) so we need an explicit barrier before
313 #define atomic_exchange_explicit(object, desired, order) \
315 __typeof__(object) __o = (object); \
316 __typeof__(desired) __d = (desired); \
318 __sync_synchronize(); \
319 __sync_lock_test_and_set(&(__o)->__val, __d); \
322 #define atomic_fetch_add_explicit(object, operand, order) \
323 ((void)(order), __sync_fetch_and_add(&(object)->__val, \
324 __atomic_apply_stride(object, operand)))
325 #define atomic_fetch_and_explicit(object, operand, order) \
326 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
327 #define atomic_fetch_or_explicit(object, operand, order) \
328 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
329 #define atomic_fetch_sub_explicit(object, operand, order) \
330 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \
331 __atomic_apply_stride(object, operand)))
332 #define atomic_fetch_xor_explicit(object, operand, order) \
333 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
334 #define atomic_load_explicit(object, order) \
335 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
336 #define atomic_store_explicit(object, desired, order) \
337 ((void)atomic_exchange_explicit(object, desired, order))
341 * Convenience functions.
343 * Don't provide these in kernel space. In kernel space, we should be
344 * disciplined enough to always provide explicit barriers.
348 #define atomic_compare_exchange_strong(object, expected, desired) \
349 atomic_compare_exchange_strong_explicit(object, expected, \
350 desired, memory_order_seq_cst, memory_order_seq_cst)
351 #define atomic_compare_exchange_weak(object, expected, desired) \
352 atomic_compare_exchange_weak_explicit(object, expected, \
353 desired, memory_order_seq_cst, memory_order_seq_cst)
354 #define atomic_exchange(object, desired) \
355 atomic_exchange_explicit(object, desired, memory_order_seq_cst)
356 #define atomic_fetch_add(object, operand) \
357 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
358 #define atomic_fetch_and(object, operand) \
359 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
360 #define atomic_fetch_or(object, operand) \
361 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
362 #define atomic_fetch_sub(object, operand) \
363 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
364 #define atomic_fetch_xor(object, operand) \
365 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
366 #define atomic_load(object) \
367 atomic_load_explicit(object, memory_order_seq_cst)
368 #define atomic_store(object, desired) \
369 atomic_store_explicit(object, desired, memory_order_seq_cst)
370 #endif /* !_KERNEL */
373 * 7.17.8 Atomic flag type and operations.
375 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some
376 * kind of compiler built-in type we could use?
382 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) }
384 static __inline _Bool
385 atomic_flag_test_and_set_explicit(volatile atomic_flag
*__object
,
386 memory_order __order
)
388 return (atomic_exchange_explicit(&__object
->__flag
, 1, __order
));
392 atomic_flag_clear_explicit(volatile atomic_flag
*__object
, memory_order __order
)
395 atomic_store_explicit(&__object
->__flag
, 0, __order
);
399 static __inline _Bool
400 atomic_flag_test_and_set(volatile atomic_flag
*__object
)
403 return (atomic_flag_test_and_set_explicit(__object
,
404 memory_order_seq_cst
));
408 atomic_flag_clear(volatile atomic_flag
*__object
)
411 atomic_flag_clear_explicit(__object
, memory_order_seq_cst
);
413 #endif /* !_KERNEL */
415 #ifdef __bool_locally_defined
417 #undef __bool_locally_defined
420 #endif /* !_STDATOMIC_H_ */