1 /*-
2 * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
3 * David Chisnall <theraven@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD$
28 */
29
30 #ifndef _STDATOMIC_H_
31 #define _STDATOMIC_H_
32
33 #include <stddef.h>
34 #include <stdint.h>
35
36 #if !defined(__has_feature)
37 #define __has_feature(x) 0
38 #endif
39 #if !defined(__has_builtin)
40 #define __has_builtin(x) 0
41 #endif
42 #if !defined(__GNUC_PREREQ__)
43 #if defined(__GNUC__) && defined(__GNUC_MINOR__)
44 #define __GNUC_PREREQ__(maj, min) \
45 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
46 #else
47 #define __GNUC_PREREQ__(maj, min) 0
48 #endif
49 #endif
50
51 #if !defined(__CLANG_ATOMICS) && !defined(__GNUC_ATOMICS)
52 #if __has_feature(c_atomic)
53 #define __CLANG_ATOMICS
54 #elif __GNUC_PREREQ__(4, 7)
55 #define __GNUC_ATOMICS
56 #elif !defined(__GNUC__)
57 #error "stdatomic.h does not support your compiler"
58 #endif
59 #endif
60
61 /*
62 * language independent type to represent a Boolean value
63 */
64
65 typedef int __Bool;
66
67 /*
68 * 7.17.1 Atomic lock-free macros.
69 */
70
71 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
72 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
73 #endif
74 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
75 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
76 #endif
77 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
78 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
79 #endif
80 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
81 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
82 #endif
83 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
84 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
85 #endif
86 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
87 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
88 #endif
89 #ifdef __GCC_ATOMIC_INT_LOCK_FREE
90 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
91 #endif
92 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
93 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
94 #endif
95 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
96 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
97 #endif
98 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
99 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
100 #endif
101
102 #if !defined(__CLANG_ATOMICS)
103 #define _Atomic(T) struct { volatile __typeof__(T) __val; }
104 #endif
105
106 /*
107 * 7.17.2 Initialization.
108 */
109
110 #if defined(__CLANG_ATOMICS)
111 #define ATOMIC_VAR_INIT(value) (value)
112 #define atomic_init(obj, value) __c11_atomic_init(obj, value)
113 #else
114 #define ATOMIC_VAR_INIT(value) { .__val = (value) }
115 #define atomic_init(obj, value) ((void)((obj)->__val = (value)))
116 #endif
117
118 /*
119 * Clang and recent GCC both provide predefined macros for the memory
120 * orderings. If we are using a compiler that doesn't define them, use the
121 * clang values - these will be ignored in the fallback path.
122 */
123
124 #ifndef __ATOMIC_RELAXED
125 #define __ATOMIC_RELAXED 0
126 #endif
127 #ifndef __ATOMIC_CONSUME
128 #define __ATOMIC_CONSUME 1
129 #endif
130 #ifndef __ATOMIC_ACQUIRE
131 #define __ATOMIC_ACQUIRE 2
132 #endif
133 #ifndef __ATOMIC_RELEASE
134 #define __ATOMIC_RELEASE 3
135 #endif
136 #ifndef __ATOMIC_ACQ_REL
137 #define __ATOMIC_ACQ_REL 4
138 #endif
139 #ifndef __ATOMIC_SEQ_CST
140 #define __ATOMIC_SEQ_CST 5
141 #endif
142
143 /*
144 * 7.17.3 Order and consistency.
145 *
146 * The memory_order_* constants that denote the barrier behaviour of the
147 * atomic operations.
148 */
149
150 typedef enum {
151 memory_order_relaxed = __ATOMIC_RELAXED,
152 memory_order_consume = __ATOMIC_CONSUME,
153 memory_order_acquire = __ATOMIC_ACQUIRE,
154 memory_order_release = __ATOMIC_RELEASE,
155 memory_order_acq_rel = __ATOMIC_ACQ_REL,
156 memory_order_seq_cst = __ATOMIC_SEQ_CST
157 } memory_order;
158
159 /*
160 * 7.17.4 Fences.
161 */
162
163 //#define __unused
164
165 //static __inline void
166 //atomic_thread_fence(memory_order __order __unused)
167 //{
168 //
169 //#ifdef __CLANG_ATOMICS
170 // __c11_atomic_thread_fence(__order);
171 //#elif defined(__GNUC_ATOMICS)
172 // __atomic_thread_fence(__order);
173 //#else
174 // __sync_synchronize();
175 //#endif
176 //}
177 //
178 //static __inline void
179 //atomic_signal_fence(memory_order __order __unused)
180 //{
181 //
182 //#ifdef __CLANG_ATOMICS
183 // __c11_atomic_signal_fence(__order);
184 //#elif defined(__GNUC_ATOMICS)
185 // __atomic_signal_fence(__order);
186 //#else
187 // __asm volatile ("" ::: "memory");
188 //#endif
189 //}
190
191 //#undef __unused
192
193 /*
194 * 7.17.5 Lock-free property.
195 */
196
197 #if defined(_KERNEL)
198 /* Atomics in kernelspace are always lock-free. */
199 #define atomic_is_lock_free(obj) \
200 ((void)(obj), (__Bool)1)
201 #elif defined(__CLANG_ATOMICS)
202 #define atomic_is_lock_free(obj) \
203 __atomic_is_lock_free(sizeof(*(obj)), obj)
204 #elif defined(__GNUC_ATOMICS)
205 #define atomic_is_lock_free(obj) \
206 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
207 #else
208 #define atomic_is_lock_free(obj) \
209 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
210 #endif
211
212 /*
213 * 7.17.6 Atomic integer types.
214 */
215
216 typedef _Atomic(__Bool) atomic_bool;
217 typedef _Atomic(char) atomic_char;
218 typedef _Atomic(signed char) atomic_schar;
219 typedef _Atomic(unsigned char) atomic_uchar;
220 typedef _Atomic(short) atomic_short;
221 typedef _Atomic(unsigned short) atomic_ushort;
222 typedef _Atomic(int) atomic_int;
223 typedef _Atomic(unsigned int) atomic_uint;
224 typedef _Atomic(long) atomic_long;
225 typedef _Atomic(unsigned long) atomic_ulong;
226 typedef _Atomic(long long) atomic_llong;
227 typedef _Atomic(unsigned long long) atomic_ullong;
228 #if 0
229 typedef _Atomic(char16_t) atomic_char16_t;
230 typedef _Atomic(char32_t) atomic_char32_t;
231 #endif
232 typedef _Atomic(wchar_t) atomic_wchar_t;
233 typedef _Atomic(int_least8_t) atomic_int_least8_t;
234 typedef _Atomic(uint_least8_t) atomic_uint_least8_t;
235 typedef _Atomic(int_least16_t) atomic_int_least16_t;
236 typedef _Atomic(uint_least16_t) atomic_uint_least16_t;
237 typedef _Atomic(int_least32_t) atomic_int_least32_t;
238 typedef _Atomic(uint_least32_t) atomic_uint_least32_t;
239 typedef _Atomic(int_least64_t) atomic_int_least64_t;
240 typedef _Atomic(uint_least64_t) atomic_uint_least64_t;
241 typedef _Atomic(int_fast8_t) atomic_int_fast8_t;
242 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t;
243 typedef _Atomic(int_fast16_t) atomic_int_fast16_t;
244 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t;
245 typedef _Atomic(int_fast32_t) atomic_int_fast32_t;
246 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t;
247 typedef _Atomic(int_fast64_t) atomic_int_fast64_t;
248 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t;
249 typedef _Atomic(intptr_t) atomic_intptr_t;
250 typedef _Atomic(uintptr_t) atomic_uintptr_t;
251 typedef _Atomic(size_t) atomic_size_t;
252 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t;
253 typedef _Atomic(intmax_t) atomic_intmax_t;
254 typedef _Atomic(uintmax_t) atomic_uintmax_t;
255
256 /*
257 * 7.17.7 Operations on atomic types.
258 */
259
260 /*
261 * Compiler-specific operations.
262 */
263
264 #if defined(__CLANG_ATOMICS)
265 #define atomic_compare_exchange_strong_explicit(object, expected, \
266 desired, success, failure) \
267 __c11_atomic_compare_exchange_strong(object, expected, desired, \
268 success, failure)
269 #define atomic_compare_exchange_weak_explicit(object, expected, \
270 desired, success, failure) \
271 __c11_atomic_compare_exchange_weak(object, expected, desired, \
272 success, failure)
273 #define atomic_exchange_explicit(object, desired, order) \
274 __c11_atomic_exchange(object, desired, order)
275 #define atomic_fetch_add_explicit(object, operand, order) \
276 __c11_atomic_fetch_add(object, operand, order)
277 #define atomic_fetch_and_explicit(object, operand, order) \
278 __c11_atomic_fetch_and(object, operand, order)
279 #define atomic_fetch_or_explicit(object, operand, order) \
280 __c11_atomic_fetch_or(object, operand, order)
281 #define atomic_fetch_sub_explicit(object, operand, order) \
282 __c11_atomic_fetch_sub(object, operand, order)
283 #define atomic_fetch_xor_explicit(object, operand, order) \
284 __c11_atomic_fetch_xor(object, operand, order)
285 #define atomic_load_explicit(object, order) \
286 __c11_atomic_load(object, order)
287 #define atomic_store_explicit(object, desired, order) \
288 __c11_atomic_store(object, desired, order)
289 #elif defined(__GNUC_ATOMICS)
290 #define atomic_compare_exchange_strong_explicit(object, expected, \
291 desired, success, failure) \
292 __atomic_compare_exchange_n(&(object)->__val, expected, \
293 desired, 0, success, failure)
294 #define atomic_compare_exchange_weak_explicit(object, expected, \
295 desired, success, failure) \
296 __atomic_compare_exchange_n(&(object)->__val, expected, \
297 desired, 1, success, failure)
298 #define atomic_exchange_explicit(object, desired, order) \
299 __atomic_exchange_n(&(object)->__val, desired, order)
300 #define atomic_fetch_add_explicit(object, operand, order) \
301 __atomic_fetch_add(&(object)->__val, operand, order)
302 #define atomic_fetch_and_explicit(object, operand, order) \
303 __atomic_fetch_and(&(object)->__val, operand, order)
304 #define atomic_fetch_or_explicit(object, operand, order) \
305 __atomic_fetch_or(&(object)->__val, operand, order)
306 #define atomic_fetch_sub_explicit(object, operand, order) \
307 __atomic_fetch_sub(&(object)->__val, operand, order)
308 #define atomic_fetch_xor_explicit(object, operand, order) \
309 __atomic_fetch_xor(&(object)->__val, operand, order)
310 #define atomic_load_explicit(object, order) \
311 __atomic_load_n(&(object)->__val, order)
312 #define atomic_store_explicit(object, desired, order) \
313 __atomic_store_n(&(object)->__val, desired, order)
314 #else
315 #define __atomic_apply_stride(object, operand) \
316 (((__typeof__((object)->__val))0) + (operand))
317 #define atomic_compare_exchange_strong_explicit(object, expected, \
318 desired, success, failure) __extension__ ({ \
319 __typeof__(expected) __ep = (expected); \
320 __typeof__(*__ep) __e = *__ep; \
321 (void)(success); (void)(failure); \
322 (__Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \
323 __e, desired)) == __e); \
324 })
325 #define atomic_compare_exchange_weak_explicit(object, expected, \
326 desired, success, failure) \
327 atomic_compare_exchange_strong_explicit(object, expected, \
328 desired, success, failure)
329 #if __has_builtin(__sync_swap)
330 /* Clang provides a full-barrier atomic exchange - use it if available. */
331 #define atomic_exchange_explicit(object, desired, order) \
332 ((void)(order), __sync_swap(&(object)->__val, desired))
333 #else
334 /*
335 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
336 * practice it is usually a full barrier) so we need an explicit barrier before
337 * it.
338 */
339 #define atomic_exchange_explicit(object, desired, order) \
340 __extension__ ({ \
341 __typeof__(object) __o = (object); \
342 __typeof__(desired) __d = (desired); \
343 (void)(order); \
344 __sync_synchronize(); \
345 __sync_lock_test_and_set(&(__o)->__val, __d); \
346 })
347 #endif
348 #define atomic_fetch_add_explicit(object, operand, order) \
349 ((void)(order), __sync_fetch_and_add(&(object)->__val, \
350 __atomic_apply_stride(object, operand)))
351 #define atomic_fetch_and_explicit(object, operand, order) \
352 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
353 #define atomic_fetch_or_explicit(object, operand, order) \
354 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
355 #define atomic_fetch_sub_explicit(object, operand, order) \
356 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \
357 __atomic_apply_stride(object, operand)))
358 #define atomic_fetch_xor_explicit(object, operand, order) \
359 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
360 #define atomic_load_explicit(object, order) \
361 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
362 #define atomic_store_explicit(object, desired, order) \
363 ((void)atomic_exchange_explicit(object, desired, order))
364 #endif
365
366 /*
367 * Convenience functions.
368 *
369 * Don't provide these in kernel space. In kernel space, we should be
370 * disciplined enough to always provide explicit barriers.
371 */
372
373 #ifndef _KERNEL
374 #define atomic_compare_exchange_strong(object, expected, desired) \
375 atomic_compare_exchange_strong_explicit(object, expected, \
376 desired, memory_order_seq_cst, memory_order_seq_cst)
377 #define atomic_compare_exchange_weak(object, expected, desired) \
378 atomic_compare_exchange_weak_explicit(object, expected, \
379 desired, memory_order_seq_cst, memory_order_seq_cst)
380 #define atomic_exchange(object, desired) \
381 atomic_exchange_explicit(object, desired, memory_order_seq_cst)
382 #define atomic_fetch_add(object, operand) \
383 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
384 #define atomic_fetch_and(object, operand) \
385 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
386 #define atomic_fetch_or(object, operand) \
387 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
388 #define atomic_fetch_sub(object, operand) \
389 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
390 #define atomic_fetch_xor(object, operand) \
391 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
392 #define atomic_load(object) \
393 atomic_load_explicit(object, memory_order_seq_cst)
394 #define atomic_store(object, desired) \
395 atomic_store_explicit(object, desired, memory_order_seq_cst)
396 #endif /* !_KERNEL */
397
398 /*
399 * 7.17.8 Atomic flag type and operations.
400 *
401 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some
402 * kind of compiler built-in type we could use?
403 */
404
405 typedef struct {
406 atomic_bool __flag;
407 } atomic_flag;
408
409 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) }
410
411 static __inline __Bool
atomic_flag_test_and_set_explicit(volatile atomic_flag * __object,memory_order __order)412 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
413 memory_order __order)
414 {
415 return (atomic_exchange_explicit(&__object->__flag, 1, __order));
416 }
417
418 static __inline void
atomic_flag_clear_explicit(volatile atomic_flag * __object,memory_order __order)419 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
420 {
421
422 atomic_store_explicit(&__object->__flag, 0, __order);
423 }
424
425 #ifndef _KERNEL
426 static __inline __Bool
atomic_flag_test_and_set(volatile atomic_flag * __object)427 atomic_flag_test_and_set(volatile atomic_flag *__object)
428 {
429
430 return (atomic_flag_test_and_set_explicit(__object,
431 memory_order_seq_cst));
432 }
433
434 static __inline void
atomic_flag_clear(volatile atomic_flag * __object)435 atomic_flag_clear(volatile atomic_flag *__object)
436 {
437
438 atomic_flag_clear_explicit(__object, memory_order_seq_cst);
439 }
440 #endif /* !_KERNEL */
441
442 #endif /* !_STDATOMIC_H_ */