1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org> 5 * David Chisnall <theraven@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 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#if defined(__cplusplus) && !defined(_Bool) 165#define _Bool bool 166#define __bool_locally_defined 167#endif 168 169/* 170 * 7.17.5 Lock-free property. 171 */ 172 173#if defined(_KERNEL) 174/* Atomics in kernelspace are always lock-free. */ 175#define atomic_is_lock_free(obj) \ 176 ((void)(obj), (_Bool)1) 177#elif defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS) 178#define atomic_is_lock_free(obj) \ 179 __atomic_is_lock_free(sizeof(*(obj)), obj) 180#else 181#define atomic_is_lock_free(obj) \ 182 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 183#endif 184 185/* 186 * 7.17.6 Atomic integer types. 187 */ 188 189typedef _Atomic(_Bool) atomic_bool; 190typedef _Atomic(char) atomic_char; 191typedef _Atomic(signed char) atomic_schar; 192typedef _Atomic(unsigned char) atomic_uchar; 193typedef _Atomic(short) atomic_short; 194typedef _Atomic(unsigned short) atomic_ushort; 195typedef _Atomic(int) atomic_int; 196typedef _Atomic(unsigned int) atomic_uint; 197typedef _Atomic(long) atomic_long; 198typedef _Atomic(unsigned long) atomic_ulong; 199typedef _Atomic(long long) atomic_llong; 200typedef _Atomic(unsigned long long) atomic_ullong; 201typedef _Atomic(__char16_t) atomic_char16_t; 202typedef _Atomic(__char32_t) atomic_char32_t; 203typedef _Atomic(___wchar_t) atomic_wchar_t; 204typedef _Atomic(__int_least8_t) atomic_int_least8_t; 205typedef _Atomic(__uint_least8_t) atomic_uint_least8_t; 206typedef _Atomic(__int_least16_t) atomic_int_least16_t; 207typedef _Atomic(__uint_least16_t) atomic_uint_least16_t; 208typedef _Atomic(__int_least32_t) atomic_int_least32_t; 209typedef _Atomic(__uint_least32_t) atomic_uint_least32_t; 210typedef _Atomic(__int_least64_t) atomic_int_least64_t; 211typedef _Atomic(__uint_least64_t) atomic_uint_least64_t; 212typedef _Atomic(__int_fast8_t) atomic_int_fast8_t; 213typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t; 214typedef _Atomic(__int_fast16_t) atomic_int_fast16_t; 215typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t; 216typedef _Atomic(__int_fast32_t) atomic_int_fast32_t; 217typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t; 218typedef _Atomic(__int_fast64_t) atomic_int_fast64_t; 219typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t; 220typedef _Atomic(__intptr_t) atomic_intptr_t; 221typedef _Atomic(__uintptr_t) atomic_uintptr_t; 222typedef _Atomic(__size_t) atomic_size_t; 223typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t; 224typedef _Atomic(__intmax_t) atomic_intmax_t; 225typedef _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, 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, expected, \ 268 desired, 1, success, failure) 269#define atomic_exchange_explicit(object, desired, order) \ 270 __atomic_exchange_n(object, desired, order) 271#define atomic_fetch_add_explicit(object, operand, order) \ 272 __atomic_fetch_add(object, operand, order) 273#define atomic_fetch_and_explicit(object, operand, order) \ 274 __atomic_fetch_and(object, operand, order) 275#define atomic_fetch_or_explicit(object, operand, order) \ 276 __atomic_fetch_or(object, operand, order) 277#define atomic_fetch_sub_explicit(object, operand, order) \ 278 __atomic_fetch_sub(object, operand, order) 279#define atomic_fetch_xor_explicit(object, operand, order) \ 280 __atomic_fetch_xor(object, operand, order) 281#define atomic_load_explicit(object, order) \ 282 __atomic_load_n(object, order) 283#define atomic_store_explicit(object, desired, order) \ 284 __atomic_store_n(object, 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 376typedef struct { 377 atomic_bool __flag; 378} atomic_flag; 379#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) } 380 381static __inline _Bool 382atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 383 memory_order __order) 384{ 385 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 386} 387 388static __inline void 389atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 390{ 391 392 atomic_store_explicit(&__object->__flag, 0, __order); 393} 394 395#ifndef _KERNEL 396static __inline _Bool 397atomic_flag_test_and_set(volatile atomic_flag *__object) 398{ 399 400 return (atomic_flag_test_and_set_explicit(__object, 401 memory_order_seq_cst)); 402} 403 404static __inline void 405atomic_flag_clear(volatile atomic_flag *__object) 406{ 407 408 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 409} 410#endif /* !_KERNEL */ 411 412#ifdef __bool_locally_defined 413#undef _Bool 414#undef __bool_locally_defined 415#endif 416 417#endif /* !_STDATOMIC_H_ */ 418