stdatomic.h revision 264496
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: stable/10/sys/sys/stdatomic.h 264496 2014-04-15 09:41:52Z tijl $ 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 125typedef 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 138static __inline void 139atomic_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 151static __inline void 152atomic_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 187typedef _Atomic(_Bool) atomic_bool; 188typedef _Atomic(char) atomic_char; 189typedef _Atomic(signed char) atomic_schar; 190typedef _Atomic(unsigned char) atomic_uchar; 191typedef _Atomic(short) atomic_short; 192typedef _Atomic(unsigned short) atomic_ushort; 193typedef _Atomic(int) atomic_int; 194typedef _Atomic(unsigned int) atomic_uint; 195typedef _Atomic(long) atomic_long; 196typedef _Atomic(unsigned long) atomic_ulong; 197typedef _Atomic(long long) atomic_llong; 198typedef _Atomic(unsigned long long) atomic_ullong; 199typedef _Atomic(__char16_t) atomic_char16_t; 200typedef _Atomic(__char32_t) atomic_char32_t; 201typedef _Atomic(___wchar_t) atomic_wchar_t; 202typedef _Atomic(__int_least8_t) atomic_int_least8_t; 203typedef _Atomic(__uint_least8_t) atomic_uint_least8_t; 204typedef _Atomic(__int_least16_t) atomic_int_least16_t; 205typedef _Atomic(__uint_least16_t) atomic_uint_least16_t; 206typedef _Atomic(__int_least32_t) atomic_int_least32_t; 207typedef _Atomic(__uint_least32_t) atomic_uint_least32_t; 208typedef _Atomic(__int_least64_t) atomic_int_least64_t; 209typedef _Atomic(__uint_least64_t) atomic_uint_least64_t; 210typedef _Atomic(__int_fast8_t) atomic_int_fast8_t; 211typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t; 212typedef _Atomic(__int_fast16_t) atomic_int_fast16_t; 213typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t; 214typedef _Atomic(__int_fast32_t) atomic_int_fast32_t; 215typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t; 216typedef _Atomic(__int_fast64_t) atomic_int_fast64_t; 217typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t; 218typedef _Atomic(__intptr_t) atomic_intptr_t; 219typedef _Atomic(__uintptr_t) atomic_uintptr_t; 220typedef _Atomic(__size_t) atomic_size_t; 221typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t; 222typedef _Atomic(__intmax_t) atomic_intmax_t; 223typedef _Atomic(__uintmax_t) atomic_uintmax_t; 224 225/* 226 * 7.17.7 Operations on atomic types. 227 */ 228 229/* 230 * Compiler-specific operations. 231 */ 232 233#if defined(__CLANG_ATOMICS) 234#define atomic_compare_exchange_strong_explicit(object, expected, \ 235 desired, success, failure) \ 236 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 237 success, failure) 238#define atomic_compare_exchange_weak_explicit(object, expected, \ 239 desired, success, failure) \ 240 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 241 success, failure) 242#define atomic_exchange_explicit(object, desired, order) \ 243 __c11_atomic_exchange(object, desired, order) 244#define atomic_fetch_add_explicit(object, operand, order) \ 245 __c11_atomic_fetch_add(object, operand, order) 246#define atomic_fetch_and_explicit(object, operand, order) \ 247 __c11_atomic_fetch_and(object, operand, order) 248#define atomic_fetch_or_explicit(object, operand, order) \ 249 __c11_atomic_fetch_or(object, operand, order) 250#define atomic_fetch_sub_explicit(object, operand, order) \ 251 __c11_atomic_fetch_sub(object, operand, order) 252#define atomic_fetch_xor_explicit(object, operand, order) \ 253 __c11_atomic_fetch_xor(object, operand, order) 254#define atomic_load_explicit(object, order) \ 255 __c11_atomic_load(object, order) 256#define atomic_store_explicit(object, desired, order) \ 257 __c11_atomic_store(object, desired, order) 258#elif defined(__GNUC_ATOMICS) 259#define atomic_compare_exchange_strong_explicit(object, expected, \ 260 desired, success, failure) \ 261 __atomic_compare_exchange_n(&(object)->__val, expected, \ 262 desired, 0, success, failure) 263#define atomic_compare_exchange_weak_explicit(object, expected, \ 264 desired, success, failure) \ 265 __atomic_compare_exchange_n(&(object)->__val, expected, \ 266 desired, 1, success, failure) 267#define atomic_exchange_explicit(object, desired, order) \ 268 __atomic_exchange_n(&(object)->__val, desired, order) 269#define atomic_fetch_add_explicit(object, operand, order) \ 270 __atomic_fetch_add(&(object)->__val, operand, order) 271#define atomic_fetch_and_explicit(object, operand, order) \ 272 __atomic_fetch_and(&(object)->__val, operand, order) 273#define atomic_fetch_or_explicit(object, operand, order) \ 274 __atomic_fetch_or(&(object)->__val, operand, order) 275#define atomic_fetch_sub_explicit(object, operand, order) \ 276 __atomic_fetch_sub(&(object)->__val, operand, order) 277#define atomic_fetch_xor_explicit(object, operand, order) \ 278 __atomic_fetch_xor(&(object)->__val, operand, order) 279#define atomic_load_explicit(object, order) \ 280 __atomic_load_n(&(object)->__val, order) 281#define atomic_store_explicit(object, desired, order) \ 282 __atomic_store_n(&(object)->__val, desired, order) 283#else 284#define __atomic_apply_stride(object, operand) \ 285 (((__typeof__((object)->__val))0) + (operand)) 286#define atomic_compare_exchange_strong_explicit(object, expected, \ 287 desired, success, failure) __extension__ ({ \ 288 __typeof__(expected) __ep = (expected); \ 289 __typeof__(*__ep) __e = *__ep; \ 290 (void)(success); (void)(failure); \ 291 (_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 292 __e, desired)) == __e); \ 293}) 294#define atomic_compare_exchange_weak_explicit(object, expected, \ 295 desired, success, failure) \ 296 atomic_compare_exchange_strong_explicit(object, expected, \ 297 desired, success, failure) 298#if __has_builtin(__sync_swap) 299/* Clang provides a full-barrier atomic exchange - use it if available. */ 300#define atomic_exchange_explicit(object, desired, order) \ 301 ((void)(order), __sync_swap(&(object)->__val, desired)) 302#else 303/* 304 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 305 * practice it is usually a full barrier) so we need an explicit barrier before 306 * it. 307 */ 308#define atomic_exchange_explicit(object, desired, order) \ 309__extension__ ({ \ 310 __typeof__(object) __o = (object); \ 311 __typeof__(desired) __d = (desired); \ 312 (void)(order); \ 313 __sync_synchronize(); \ 314 __sync_lock_test_and_set(&(__o)->__val, __d); \ 315}) 316#endif 317#define atomic_fetch_add_explicit(object, operand, order) \ 318 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 319 __atomic_apply_stride(object, operand))) 320#define atomic_fetch_and_explicit(object, operand, order) \ 321 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 322#define atomic_fetch_or_explicit(object, operand, order) \ 323 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 324#define atomic_fetch_sub_explicit(object, operand, order) \ 325 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 326 __atomic_apply_stride(object, operand))) 327#define atomic_fetch_xor_explicit(object, operand, order) \ 328 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 329#define atomic_load_explicit(object, order) \ 330 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 331#define atomic_store_explicit(object, desired, order) \ 332 ((void)atomic_exchange_explicit(object, desired, order)) 333#endif 334 335/* 336 * Convenience functions. 337 * 338 * Don't provide these in kernel space. In kernel space, we should be 339 * disciplined enough to always provide explicit barriers. 340 */ 341 342#ifndef _KERNEL 343#define atomic_compare_exchange_strong(object, expected, desired) \ 344 atomic_compare_exchange_strong_explicit(object, expected, \ 345 desired, memory_order_seq_cst, memory_order_seq_cst) 346#define atomic_compare_exchange_weak(object, expected, desired) \ 347 atomic_compare_exchange_weak_explicit(object, expected, \ 348 desired, memory_order_seq_cst, memory_order_seq_cst) 349#define atomic_exchange(object, desired) \ 350 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 351#define atomic_fetch_add(object, operand) \ 352 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 353#define atomic_fetch_and(object, operand) \ 354 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 355#define atomic_fetch_or(object, operand) \ 356 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 357#define atomic_fetch_sub(object, operand) \ 358 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 359#define atomic_fetch_xor(object, operand) \ 360 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 361#define atomic_load(object) \ 362 atomic_load_explicit(object, memory_order_seq_cst) 363#define atomic_store(object, desired) \ 364 atomic_store_explicit(object, desired, memory_order_seq_cst) 365#endif /* !_KERNEL */ 366 367/* 368 * 7.17.8 Atomic flag type and operations. 369 * 370 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 371 * kind of compiler built-in type we could use? 372 */ 373 374typedef struct { 375 atomic_bool __flag; 376} atomic_flag; 377 378#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) } 379 380static __inline _Bool 381atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 382 memory_order __order) 383{ 384 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 385} 386 387static __inline void 388atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 389{ 390 391 atomic_store_explicit(&__object->__flag, 0, __order); 392} 393 394#ifndef _KERNEL 395static __inline _Bool 396atomic_flag_test_and_set(volatile atomic_flag *__object) 397{ 398 399 return (atomic_flag_test_and_set_explicit(__object, 400 memory_order_seq_cst)); 401} 402 403static __inline void 404atomic_flag_clear(volatile atomic_flag *__object) 405{ 406 407 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 408} 409#endif /* !_KERNEL */ 410 411#endif /* !_STDATOMIC_H_ */ 412