1 /*- 2 * Copyright (c) 2011 Ed Schouten <ed (at) FreeBSD.org> 3 * David Chisnall <theraven (at) 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 */ 125 126 typedef 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 */ 138 139 static __inline void 140 atomic_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 } 151 152 static __inline void 153 atomic_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 195 196 typedef _Atomic(bool) atomic_bool; 197 typedef _Atomic(char) atomic_char; 198 typedef _Atomic(signed char) atomic_schar; 199 typedef _Atomic(unsigned char) atomic_uchar; 200 typedef _Atomic(short) atomic_short; 201 typedef _Atomic(unsigned short) atomic_ushort; 202 typedef _Atomic(int) atomic_int; 203 typedef _Atomic(unsigned int) atomic_uint; 204 typedef _Atomic(long) atomic_long; 205 typedef _Atomic(unsigned long) atomic_ulong; 206 typedef _Atomic(long long) atomic_llong; 207 typedef _Atomic(unsigned long long) atomic_ullong; 208 typedef _Atomic(char16_t) atomic_char16_t; 209 typedef _Atomic(char32_t) atomic_char32_t; 210 typedef _Atomic(wchar_t) atomic_wchar_t; 211 typedef _Atomic(int_least8_t) atomic_int_least8_t; 212 typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 213 typedef _Atomic(int_least16_t) atomic_int_least16_t; 214 typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 215 typedef _Atomic(int_least32_t) atomic_int_least32_t; 216 typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 217 typedef _Atomic(int_least64_t) atomic_int_least64_t; 218 typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 219 typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 220 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 221 typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 222 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 223 typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 224 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 225 typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 226 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 227 typedef _Atomic(intptr_t) atomic_intptr_t; 228 typedef _Atomic(uintptr_t) atomic_uintptr_t; 229 typedef _Atomic(size_t) atomic_size_t; 230 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 231 typedef _Atomic(intmax_t) atomic_intmax_t; 232 typedef _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 */ 382 383 typedef struct { 384 atomic_bool __flag; 385 } atomic_flag; 386 387 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(0) } 388 389 static __inline bool 390 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 391 memory_order __order) 392 { 393 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 394 } 395 396 static __inline void 397 atomic_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 404 static __inline bool 405 atomic_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 } 411 412 static __inline void 413 atomic_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
