stdatomic.h revision e6c57fcb05b0dcbfa8129bb6f7d99093f4819370
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#include <stdbool.h> 36 37#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 43#else 44#error "stdatomic.h does not support your compiler" 45#endif 46 47/* 48 * 7.17.1 Atomic lock-free macros. 49 */ 50 51#ifdef __GCC_ATOMIC_BOOL_LOCK_FREE 52#define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE 53#endif 54#ifdef __GCC_ATOMIC_CHAR_LOCK_FREE 55#define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE 56#endif 57#ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE 58#define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE 59#endif 60#ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE 61#define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE 62#endif 63#ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE 64#define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE 65#endif 66#ifdef __GCC_ATOMIC_SHORT_LOCK_FREE 67#define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE 68#endif 69#ifdef __GCC_ATOMIC_INT_LOCK_FREE 70#define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE 71#endif 72#ifdef __GCC_ATOMIC_LONG_LOCK_FREE 73#define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE 74#endif 75#ifdef __GCC_ATOMIC_LLONG_LOCK_FREE 76#define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE 77#endif 78#ifdef __GCC_ATOMIC_POINTER_LOCK_FREE 79#define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE 80#endif 81 82/* 83 * 7.17.2 Initialization. 84 */ 85 86#if defined(__CLANG_ATOMICS) 87#define ATOMIC_VAR_INIT(value) (value) 88#define atomic_init(obj, value) __c11_atomic_init(obj, value) 89#else 90#define ATOMIC_VAR_INIT(value) { .__val = (value) } 91#define atomic_init(obj, value) ((void)((obj)->__val = (value))) 92#endif 93 94/* 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. 98 */ 99 100#ifndef __ATOMIC_RELAXED 101#define __ATOMIC_RELAXED 0 102#endif 103#ifndef __ATOMIC_CONSUME 104#define __ATOMIC_CONSUME 1 105#endif 106#ifndef __ATOMIC_ACQUIRE 107#define __ATOMIC_ACQUIRE 2 108#endif 109#ifndef __ATOMIC_RELEASE 110#define __ATOMIC_RELEASE 3 111#endif 112#ifndef __ATOMIC_ACQ_REL 113#define __ATOMIC_ACQ_REL 4 114#endif 115#ifndef __ATOMIC_SEQ_CST 116#define __ATOMIC_SEQ_CST 5 117#endif 118 119/* 120 * 7.17.3 Order and consistency. 121 * 122 * The memory_order_* constants that denote the barrier behaviour of the 123 * atomic operations. 124 */ 125 126typedef enum { 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 133} memory_order; 134 135/* 136 * 7.17.4 Fences. 137 */ 138 139static __inline void 140atomic_thread_fence(memory_order __order __unused) 141{ 142 143#ifdef __CLANG_ATOMICS 144 __c11_atomic_thread_fence(__order); 145#elif defined(__GNUC_ATOMICS) 146 __atomic_thread_fence(__order); 147#else 148 __sync_synchronize(); 149#endif 150} 151 152static __inline void 153atomic_signal_fence(memory_order __order __unused) 154{ 155 156#ifdef __CLANG_ATOMICS 157 __c11_atomic_signal_fence(__order); 158#elif defined(__GNUC_ATOMICS) 159 __atomic_signal_fence(__order); 160#else 161 __asm volatile ("" ::: "memory"); 162#endif 163} 164 165/* 166 * 7.17.5 Lock-free property. 167 */ 168 169#if defined(_KERNEL) 170/* Atomics in kernelspace are always lock-free. */ 171#define atomic_is_lock_free(obj) \ 172 ((void)(obj), (_Bool)1) 173#elif defined(__CLANG_ATOMICS) 174#define atomic_is_lock_free(obj) \ 175 __atomic_is_lock_free(sizeof(*(obj)), obj) 176#elif defined(__GNUC_ATOMICS) 177#define atomic_is_lock_free(obj) \ 178 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) 179#else 180#define atomic_is_lock_free(obj) \ 181 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 182#endif 183 184/* 185 * 7.17.6 Atomic integer types. 186 */ 187 188#if !__has_extension(c_atomic) && !__has_extension(cxx_atomic) 189/* 190 * No native support for _Atomic(). Place object in structure to prevent 191 * most forms of direct non-atomic access. 192 */ 193#define _Atomic(T) struct { T volatile __val; } 194#endif 195 196typedef _Atomic(bool) atomic_bool; 197typedef _Atomic(char) atomic_char; 198typedef _Atomic(signed char) atomic_schar; 199typedef _Atomic(unsigned char) atomic_uchar; 200typedef _Atomic(short) atomic_short; 201typedef _Atomic(unsigned short) atomic_ushort; 202typedef _Atomic(int) atomic_int; 203typedef _Atomic(unsigned int) atomic_uint; 204typedef _Atomic(long) atomic_long; 205typedef _Atomic(unsigned long) atomic_ulong; 206typedef _Atomic(long long) atomic_llong; 207typedef _Atomic(unsigned long long) atomic_ullong; 208typedef _Atomic(char16_t) atomic_char16_t; 209typedef _Atomic(char32_t) atomic_char32_t; 210typedef _Atomic(wchar_t) atomic_wchar_t; 211typedef _Atomic(int_least8_t) atomic_int_least8_t; 212typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 213typedef _Atomic(int_least16_t) atomic_int_least16_t; 214typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 215typedef _Atomic(int_least32_t) atomic_int_least32_t; 216typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 217typedef _Atomic(int_least64_t) atomic_int_least64_t; 218typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 219typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 220typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 221typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 222typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 223typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 224typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 225typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 226typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 227typedef _Atomic(intptr_t) atomic_intptr_t; 228typedef _Atomic(uintptr_t) atomic_uintptr_t; 229typedef _Atomic(size_t) atomic_size_t; 230typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 231typedef _Atomic(intmax_t) atomic_intmax_t; 232typedef _Atomic(uintmax_t) atomic_uintmax_t; 233 234/* 235 * 7.17.7 Operations on atomic types. 236 */ 237 238/* 239 * Compiler-specific operations. 240 */ 241 242#if defined(__CLANG_ATOMICS) 243#define atomic_compare_exchange_strong_explicit(object, expected, \ 244 desired, success, failure) \ 245 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 246 success, failure) 247#define atomic_compare_exchange_weak_explicit(object, expected, \ 248 desired, success, failure) \ 249 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 250 success, failure) 251#define atomic_exchange_explicit(object, desired, order) \ 252 __c11_atomic_exchange(object, desired, order) 253#define atomic_fetch_add_explicit(object, operand, order) \ 254 __c11_atomic_fetch_add(object, operand, order) 255#define atomic_fetch_and_explicit(object, operand, order) \ 256 __c11_atomic_fetch_and(object, operand, order) 257#define atomic_fetch_or_explicit(object, operand, order) \ 258 __c11_atomic_fetch_or(object, operand, order) 259#define atomic_fetch_sub_explicit(object, operand, order) \ 260 __c11_atomic_fetch_sub(object, operand, order) 261#define atomic_fetch_xor_explicit(object, operand, order) \ 262 __c11_atomic_fetch_xor(object, operand, order) 263#define atomic_load_explicit(object, order) \ 264 __c11_atomic_load(object, order) 265#define atomic_store_explicit(object, desired, order) \ 266 __c11_atomic_store(object, desired, order) 267#elif defined(__GNUC_ATOMICS) 268#define atomic_compare_exchange_strong_explicit(object, expected, \ 269 desired, success, failure) \ 270 __atomic_compare_exchange_n(&(object)->__val, expected, \ 271 desired, 0, success, failure) 272#define atomic_compare_exchange_weak_explicit(object, expected, \ 273 desired, success, failure) \ 274 __atomic_compare_exchange_n(&(object)->__val, expected, \ 275 desired, 1, success, failure) 276#define atomic_exchange_explicit(object, desired, order) \ 277 __atomic_exchange_n(&(object)->__val, desired, order) 278#define atomic_fetch_add_explicit(object, operand, order) \ 279 __atomic_fetch_add(&(object)->__val, operand, order) 280#define atomic_fetch_and_explicit(object, operand, order) \ 281 __atomic_fetch_and(&(object)->__val, operand, order) 282#define atomic_fetch_or_explicit(object, operand, order) \ 283 __atomic_fetch_or(&(object)->__val, operand, order) 284#define atomic_fetch_sub_explicit(object, operand, order) \ 285 __atomic_fetch_sub(&(object)->__val, operand, order) 286#define atomic_fetch_xor_explicit(object, operand, order) \ 287 __atomic_fetch_xor(&(object)->__val, operand, order) 288#define atomic_load_explicit(object, order) \ 289 __atomic_load_n(&(object)->__val, order) 290#define atomic_store_explicit(object, desired, order) \ 291 __atomic_store_n(&(object)->__val, desired, order) 292#else 293#define __atomic_apply_stride(object, operand) \ 294 (((__typeof__((object)->__val))0) + (operand)) 295#define atomic_compare_exchange_strong_explicit(object, expected, \ 296 desired, success, failure) __extension__ ({ \ 297 __typeof__(expected) __ep = (expected); \ 298 __typeof__(*__ep) __e = *__ep; \ 299 (void)(success); (void)(failure); \ 300 (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 301 __e, desired)) == __e); \ 302}) 303#define atomic_compare_exchange_weak_explicit(object, expected, \ 304 desired, success, failure) \ 305 atomic_compare_exchange_strong_explicit(object, expected, \ 306 desired, success, failure) 307#if __has_builtin(__sync_swap) 308/* Clang provides a full-barrier atomic exchange - use it if available. */ 309#define atomic_exchange_explicit(object, desired, order) \ 310 ((void)(order), __sync_swap(&(object)->__val, desired)) 311#else 312/* 313 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 314 * practice it is usually a full barrier) so we need an explicit barrier before 315 * it. 316 */ 317#define atomic_exchange_explicit(object, desired, order) \ 318__extension__ ({ \ 319 __typeof__(object) __o = (object); \ 320 __typeof__(desired) __d = (desired); \ 321 (void)(order); \ 322 __sync_synchronize(); \ 323 __sync_lock_test_and_set(&(__o)->__val, __d); \ 324}) 325#endif 326#define atomic_fetch_add_explicit(object, operand, order) \ 327 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 328 __atomic_apply_stride(object, operand))) 329#define atomic_fetch_and_explicit(object, operand, order) \ 330 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 331#define atomic_fetch_or_explicit(object, operand, order) \ 332 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 333#define atomic_fetch_sub_explicit(object, operand, order) \ 334 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 335 __atomic_apply_stride(object, operand))) 336#define atomic_fetch_xor_explicit(object, operand, order) \ 337 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 338#define atomic_load_explicit(object, order) \ 339 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 340#define atomic_store_explicit(object, desired, order) \ 341 ((void)atomic_exchange_explicit(object, desired, order)) 342#endif 343 344/* 345 * Convenience functions. 346 * 347 * Don't provide these in kernel space. In kernel space, we should be 348 * disciplined enough to always provide explicit barriers. 349 */ 350 351#ifndef _KERNEL 352#define atomic_compare_exchange_strong(object, expected, desired) \ 353 atomic_compare_exchange_strong_explicit(object, expected, \ 354 desired, memory_order_seq_cst, memory_order_seq_cst) 355#define atomic_compare_exchange_weak(object, expected, desired) \ 356 atomic_compare_exchange_weak_explicit(object, expected, \ 357 desired, memory_order_seq_cst, memory_order_seq_cst) 358#define atomic_exchange(object, desired) \ 359 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 360#define atomic_fetch_add(object, operand) \ 361 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 362#define atomic_fetch_and(object, operand) \ 363 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 364#define atomic_fetch_or(object, operand) \ 365 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 366#define atomic_fetch_sub(object, operand) \ 367 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 368#define atomic_fetch_xor(object, operand) \ 369 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 370#define atomic_load(object) \ 371 atomic_load_explicit(object, memory_order_seq_cst) 372#define atomic_store(object, desired) \ 373 atomic_store_explicit(object, desired, memory_order_seq_cst) 374#endif /* !_KERNEL */ 375 376/* 377 * 7.17.8 Atomic flag type and operations. 378 * 379 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 380 * kind of compiler built-in type we could use? 381 */ 382 383typedef struct { 384 atomic_bool __flag; 385} atomic_flag; 386 387#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) } 388 389static __inline bool 390atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 391 memory_order __order) 392{ 393 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 394} 395 396static __inline void 397atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 398{ 399 400 atomic_store_explicit(&__object->__flag, 0, __order); 401} 402 403#ifndef _KERNEL 404static __inline bool 405atomic_flag_test_and_set(volatile atomic_flag *__object) 406{ 407 408 return (atomic_flag_test_and_set_explicit(__object, 409 memory_order_seq_cst)); 410} 411 412static __inline void 413atomic_flag_clear(volatile atomic_flag *__object) 414{ 415 416 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 417} 418#endif /* !_KERNEL */ 419 420#endif /* !_STDATOMIC_H_ */ 421