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 <sys/cdefs.h>
34 #include <sys/_types.h>
35
36 #if __has_extension(c_atomic) || __has_extension(cxx_atomic)
37 #define __CLANG_ATOMICS
38 #elif __GNUC_PREREQ__(4, 7)
39 #define __GNUC_ATOMICS
40 #elif defined(__GNUC__)
41 #define __SYNC_ATOMICS
42 #else
43 #error "stdatomic.h does not support your compiler"
44 #endif
45
46 /*
47 * 7.17.1 Atomic lock-free macros.
48 */
49
50 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
51 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE
52 #endif
53 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
54 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE
55 #endif
56 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
57 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE
58 #endif
59 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
60 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE
61 #endif
62 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
63 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE
64 #endif
65 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
66 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE
67 #endif
68 #ifdef __GCC_ATOMIC_INT_LOCK_FREE
69 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE
70 #endif
71 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
72 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE
73 #endif
74 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
75 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE
76 #endif
77 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
78 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE
79 #endif
80
81 /*
82 * 7.17.2 Initialization.
83 */
84
85 #if defined(__CLANG_ATOMICS)
86 #define ATOMIC_VAR_INIT(value) (value)
87 #define atomic_init(obj, value) __c11_atomic_init(obj, value)
88 #else
89 #define ATOMIC_VAR_INIT(value) { .__val = (value) }
90 #define atomic_init(obj, value) ((void)((obj)->__val = (value)))
91 #endif
92
93 /*
94 * Clang and recent GCC both provide predefined macros for the memory
95 * orderings. If we are using a compiler that doesn't define them, use the
96 * clang values - these will be ignored in the fallback path.
97 */
98
99 #ifndef __ATOMIC_RELAXED
100 #define __ATOMIC_RELAXED 0
101 #endif
102 #ifndef __ATOMIC_CONSUME
103 #define __ATOMIC_CONSUME 1
104 #endif
105 #ifndef __ATOMIC_ACQUIRE
106 #define __ATOMIC_ACQUIRE 2
107 #endif
108 #ifndef __ATOMIC_RELEASE
109 #define __ATOMIC_RELEASE 3
110 #endif
111 #ifndef __ATOMIC_ACQ_REL
112 #define __ATOMIC_ACQ_REL 4
113 #endif
114 #ifndef __ATOMIC_SEQ_CST
115 #define __ATOMIC_SEQ_CST 5
116 #endif
117
118 /*
119 * 7.17.3 Order and consistency.
120 *
121 * The memory_order_* constants that denote the barrier behaviour of the
122 * atomic operations.
123 */
124
125 typedef enum {
126 memory_order_relaxed = __ATOMIC_RELAXED,
127 memory_order_consume = __ATOMIC_CONSUME,
128 memory_order_acquire = __ATOMIC_ACQUIRE,
129 memory_order_release = __ATOMIC_RELEASE,
130 memory_order_acq_rel = __ATOMIC_ACQ_REL,
131 memory_order_seq_cst = __ATOMIC_SEQ_CST
132 } memory_order;
133
134 /*
135 * 7.17.4 Fences.
136 */
137
138 static __inline void
atomic_thread_fence(memory_order __order __unused)139 atomic_thread_fence(memory_order __order __unused)
140 {
141
142 #ifdef __CLANG_ATOMICS
143 __c11_atomic_thread_fence(__order);
144 #elif defined(__GNUC_ATOMICS)
145 __atomic_thread_fence(__order);
146 #else
147 __sync_synchronize();
148 #endif
149 }
150
151 static __inline void
atomic_signal_fence(memory_order __order __unused)152 atomic_signal_fence(memory_order __order __unused)
153 {
154
155 #ifdef __CLANG_ATOMICS
156 __c11_atomic_signal_fence(__order);
157 #elif defined(__GNUC_ATOMICS)
158 __atomic_signal_fence(__order);
159 #else
160 __asm volatile ("" ::: "memory");
161 #endif
162 }
163
164 /*
165 * 7.17.5 Lock-free property.
166 */
167
168 #if defined(_KERNEL)
169 /* Atomics in kernelspace are always lock-free. */
170 #define atomic_is_lock_free(obj) \
171 ((void)(obj), (_Bool)1)
172 #elif defined(__CLANG_ATOMICS)
173 #define atomic_is_lock_free(obj) \
174 __atomic_is_lock_free(sizeof(*(obj)), obj)
175 #elif defined(__GNUC_ATOMICS)
176 #define atomic_is_lock_free(obj) \
177 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
178 #else
179 #define atomic_is_lock_free(obj) \
180 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
181 #endif
182
183 /*
184 * 7.17.6 Atomic integer types.
185 */
186
187 typedef _Atomic(_Bool) atomic_bool;
188 typedef _Atomic(char) atomic_char;
189 typedef _Atomic(signed char) atomic_schar;
190 typedef _Atomic(unsigned char) atomic_uchar;
191 typedef _Atomic(short) atomic_short;
192 typedef _Atomic(unsigned short) atomic_ushort;
193 typedef _Atomic(int) atomic_int;
194 typedef _Atomic(unsigned int) atomic_uint;
195 typedef _Atomic(long) atomic_long;
196 typedef _Atomic(unsigned long) atomic_ulong;
197 typedef _Atomic(long long) atomic_llong;
198 typedef _Atomic(unsigned long long) atomic_ullong;
199 #if 0
200 typedef _Atomic(__char16_t) atomic_char16_t;
201 typedef _Atomic(__char32_t) atomic_char32_t;
202 #endif
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;
226
227 /*
228 * 7.17.7 Operations on atomic types.
229 */
230
231 /*
232 * Compiler-specific operations.
233 */
234
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, \
239 success, failure)
240 #define atomic_compare_exchange_weak_explicit(object, expected, \
241 desired, success, failure) \
242 __c11_atomic_compare_exchange_weak(object, expected, desired, \
243 success, failure)
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)
285 #else
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); \
295 })
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))
304 #else
305 /*
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
308 * it.
309 */
310 #define atomic_exchange_explicit(object, desired, order) \
311 __extension__ ({ \
312 __typeof__(object) __o = (object); \
313 __typeof__(desired) __d = (desired); \
314 (void)(order); \
315 __sync_synchronize(); \
316 __sync_lock_test_and_set(&(__o)->__val, __d); \
317 })
318 #endif
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))
335 #endif
336
337 /*
338 * Convenience functions.
339 *
340 * Don't provide these in kernel space. In kernel space, we should be
341 * disciplined enough to always provide explicit barriers.
342 */
343
344 #ifndef _KERNEL
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 */
368
369 /*
370 * 7.17.8 Atomic flag type and operations.
371 *
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?
374 */
375
376 typedef struct {
377 atomic_bool __flag;
378 } atomic_flag;
379
380 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) }
381
382 static __inline _Bool
atomic_flag_test_and_set_explicit(volatile atomic_flag * __object,memory_order __order)383 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
384 memory_order __order)
385 {
386 return (atomic_exchange_explicit(&__object->__flag, 1, __order));
387 }
388
389 static __inline void
atomic_flag_clear_explicit(volatile atomic_flag * __object,memory_order __order)390 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
391 {
392
393 atomic_store_explicit(&__object->__flag, 0, __order);
394 }
395
396 #ifndef _KERNEL
397 static __inline _Bool
atomic_flag_test_and_set(volatile atomic_flag * __object)398 atomic_flag_test_and_set(volatile atomic_flag *__object)
399 {
400
401 return (atomic_flag_test_and_set_explicit(__object,
402 memory_order_seq_cst));
403 }
404
405 static __inline void
atomic_flag_clear(volatile atomic_flag * __object)406 atomic_flag_clear(volatile atomic_flag *__object)
407 {
408
409 atomic_flag_clear_explicit(__object, memory_order_seq_cst);
410 }
411 #endif /* !_KERNEL */
412
413 #endif /* !_STDATOMIC_H_ */
414