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 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 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 typedef _Atomic(__char16_t) atomic_char16_t; 200 typedef _Atomic(__char32_t) atomic_char32_t; 201 typedef _Atomic(___wchar_t) atomic_wchar_t; 202 typedef _Atomic(__int_least8_t) atomic_int_least8_t; 203 typedef _Atomic(__uint_least8_t) atomic_uint_least8_t; 204 typedef _Atomic(__int_least16_t) atomic_int_least16_t; 205 typedef _Atomic(__uint_least16_t) atomic_uint_least16_t; 206 typedef _Atomic(__int_least32_t) atomic_int_least32_t; 207 typedef _Atomic(__uint_least32_t) atomic_uint_least32_t; 208 typedef _Atomic(__int_least64_t) atomic_int_least64_t; 209 typedef _Atomic(__uint_least64_t) atomic_uint_least64_t; 210 typedef _Atomic(__int_fast8_t) atomic_int_fast8_t; 211 typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t; 212 typedef _Atomic(__int_fast16_t) atomic_int_fast16_t; 213 typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t; 214 typedef _Atomic(__int_fast32_t) atomic_int_fast32_t; 215 typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t; 216 typedef _Atomic(__int_fast64_t) atomic_int_fast64_t; 217 typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t; 218 typedef _Atomic(__intptr_t) atomic_intptr_t; 219 typedef _Atomic(__uintptr_t) atomic_uintptr_t; 220 typedef _Atomic(__size_t) atomic_size_t; 221 typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t; 222 typedef _Atomic(__intmax_t) atomic_intmax_t; 223 typedef _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 */ 373 374 typedef struct { 375 atomic_bool __flag; 376 } atomic_flag; 377 378 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) } 379 380 static __inline _Bool 381 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 382 memory_order __order) 383 { 384 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 385 } 386 387 static __inline void 388 atomic_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 395 static __inline _Bool 396 atomic_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 } 402 403 static __inline void 404 atomic_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