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 65typedef 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 150typedef 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 216typedef _Atomic(__Bool) atomic_bool; 217typedef _Atomic(char) atomic_char; 218typedef _Atomic(signed char) atomic_schar; 219typedef _Atomic(unsigned char) atomic_uchar; 220typedef _Atomic(short) atomic_short; 221typedef _Atomic(unsigned short) atomic_ushort; 222typedef _Atomic(int) atomic_int; 223typedef _Atomic(unsigned int) atomic_uint; 224typedef _Atomic(long) atomic_long; 225typedef _Atomic(unsigned long) atomic_ulong; 226typedef _Atomic(long long) atomic_llong; 227typedef _Atomic(unsigned long long) atomic_ullong; 228#if 0 229typedef _Atomic(char16_t) atomic_char16_t; 230typedef _Atomic(char32_t) atomic_char32_t; 231#endif 232typedef _Atomic(wchar_t) atomic_wchar_t; 233typedef _Atomic(int_least8_t) atomic_int_least8_t; 234typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 235typedef _Atomic(int_least16_t) atomic_int_least16_t; 236typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 237typedef _Atomic(int_least32_t) atomic_int_least32_t; 238typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 239typedef _Atomic(int_least64_t) atomic_int_least64_t; 240typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 241typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 242typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 243typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 244typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 245typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 246typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 247typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 248typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 249typedef _Atomic(intptr_t) atomic_intptr_t; 250typedef _Atomic(uintptr_t) atomic_uintptr_t; 251typedef _Atomic(size_t) atomic_size_t; 252typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 253typedef _Atomic(intmax_t) atomic_intmax_t; 254typedef _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 405typedef struct { 406 atomic_bool __flag; 407} atomic_flag; 408 409#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) } 410 411static __inline __Bool 412atomic_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 418static __inline void 419atomic_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 426static __inline __Bool 427atomic_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 434static __inline void 435atomic_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_ */