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 35 #if defined(__cplusplus) && __cplusplus >= 201103L && defined(_USING_LIBCXX) 36 # ifdef __clang__ 37 # if __has_feature(cxx_atomic) 38 # define _STDATOMIC_HAVE_ATOMIC 39 # endif 40 # else /* gcc */ 41 # define _STDATOMIC_HAVE_ATOMIC 42 # endif 43 #endif 44 45 #ifdef _STDATOMIC_HAVE_ATOMIC 46 47 /* We have a usable C++ <atomic>; use it instead. */ 48 49 #include <atomic> 50 51 #undef _Atomic 52 /* Also defined by <atomic> for gcc. But not used in macros. */ 53 /* Also a clang intrinsic. */ 54 /* Should not be used by client code before this file is */ 55 /* included. The definitions in <atomic> themselves see */ 56 /* the old definition, as they should. */ 57 /* Client code sees the following definition. */ 58 59 #define _Atomic(t) std::atomic<t> 60 61 using std::atomic_is_lock_free; 62 using std::atomic_init; 63 using std::atomic_store; 64 using std::atomic_store_explicit; 65 using std::atomic_load; 66 using std::atomic_load_explicit; 67 using std::atomic_exchange; 68 using std::atomic_exchange_explicit; 69 using std::atomic_compare_exchange_strong; 70 using std::atomic_compare_exchange_strong_explicit; 71 using std::atomic_compare_exchange_weak; 72 using std::atomic_compare_exchange_weak_explicit; 73 using std::atomic_fetch_add; 74 using std::atomic_fetch_add_explicit; 75 using std::atomic_fetch_sub; 76 using std::atomic_fetch_sub_explicit; 77 using std::atomic_fetch_or; 78 using std::atomic_fetch_or_explicit; 79 using std::atomic_fetch_xor; 80 using std::atomic_fetch_xor_explicit; 81 using std::atomic_fetch_and; 82 using std::atomic_fetch_and_explicit; 83 using std::atomic_thread_fence; 84 using std::atomic_signal_fence; 85 86 using std::memory_order; 87 using std::memory_order_relaxed; 88 using std::memory_order_consume; 89 using std::memory_order_acquire; 90 using std::memory_order_release; 91 using std::memory_order_acq_rel; 92 using std::memory_order_seq_cst; 93 94 using std::atomic_bool; 95 using std::atomic_char; 96 using std::atomic_schar; 97 using std::atomic_uchar; 98 using std::atomic_short; 99 using std::atomic_ushort; 100 using std::atomic_int; 101 using std::atomic_uint; 102 using std::atomic_long; 103 using std::atomic_ulong; 104 using std::atomic_llong; 105 using std::atomic_ullong; 106 using std::atomic_char16_t; 107 using std::atomic_char32_t; 108 using std::atomic_wchar_t; 109 using std::atomic_int_least8_t; 110 using std::atomic_uint_least8_t; 111 using std::atomic_int_least16_t; 112 using std::atomic_uint_least16_t; 113 using std::atomic_int_least32_t; 114 using std::atomic_uint_least32_t; 115 using std::atomic_int_least64_t; 116 using std::atomic_uint_least64_t; 117 using std::atomic_int_fast8_t; 118 using std::atomic_uint_fast8_t; 119 using std::atomic_int_fast16_t; 120 using std::atomic_uint_fast16_t; 121 using std::atomic_int_fast32_t; 122 using std::atomic_uint_fast32_t; 123 using std::atomic_int_fast64_t; 124 using std::atomic_uint_fast64_t; 125 using std::atomic_intptr_t; 126 using std::atomic_uintptr_t; 127 using std::atomic_size_t; 128 using std::atomic_ptrdiff_t; 129 using std::atomic_intmax_t; 130 using std::atomic_uintmax_t; 131 132 #else /* <atomic> unavailable, possibly because this is C, not C++ */ 133 134 #include <sys/types.h> 135 #include <stdbool.h> 136 137 /* 138 * C: Do it ourselves. 139 * Note that the runtime representation defined here should be compatible 140 * with the C++ one, i.e. an _Atomic(T) needs to contain the same 141 * bits as a T. 142 */ 143 144 #include <stddef.h> /* For ptrdiff_t. */ 145 #include <stdint.h> /* TODO: don't drag in all the macros, just the types. */ 146 // Include uchar.h only when needed. Bionic's stdatomic.h is also used for the 147 // host (via a copy in prebuilts/clang) and uchar.h is not available in the 148 // glibc used for the host. 149 #if __STDC_VERSION__ >= 201112L 150 # include <uchar.h> /* For char16_t and char32_t. */ 151 #endif 152 153 154 #ifdef __clang__ 155 # if __has_extension(c_atomic) || __has_extension(cxx_atomic) 156 # define __CLANG_ATOMICS 157 # else 158 # error "stdatomic.h does not support your compiler" 159 # endif 160 # if __has_builtin(__sync_swap) 161 # define __HAS_BUILTIN_SYNC_SWAP 162 # endif 163 #else 164 # define __GNUC_ATOMICS 165 #endif 166 167 /* 168 * 7.17.1 Atomic lock-free macros. 169 */ 170 171 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE 172 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE 173 #endif 174 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE 175 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE 176 #endif 177 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE 178 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE 179 #endif 180 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE 181 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE 182 #endif 183 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE 184 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE 185 #endif 186 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE 187 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE 188 #endif 189 #ifdef __GCC_ATOMIC_INT_LOCK_FREE 190 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE 191 #endif 192 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE 193 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE 194 #endif 195 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE 196 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE 197 #endif 198 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE 199 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE 200 #endif 201 202 /* 203 * 7.17.2 Initialization. 204 */ 205 206 #if defined(__CLANG_ATOMICS) 207 #define ATOMIC_VAR_INIT(value) (value) 208 #define atomic_init(obj, value) __c11_atomic_init(obj, value) 209 #else 210 #define ATOMIC_VAR_INIT(value) { .__val = (value) } 211 #define atomic_init(obj, value) ((void)((obj)->__val = (value))) 212 #endif 213 214 /* 215 * Clang and recent GCC both provide predefined macros for the memory 216 * orderings. If we are using a compiler that doesn't define them, use the 217 * clang values - these will be ignored in the fallback path. 218 */ 219 220 #ifndef __ATOMIC_RELAXED 221 #define __ATOMIC_RELAXED 0 222 #endif 223 #ifndef __ATOMIC_CONSUME 224 #define __ATOMIC_CONSUME 1 225 #endif 226 #ifndef __ATOMIC_ACQUIRE 227 #define __ATOMIC_ACQUIRE 2 228 #endif 229 #ifndef __ATOMIC_RELEASE 230 #define __ATOMIC_RELEASE 3 231 #endif 232 #ifndef __ATOMIC_ACQ_REL 233 #define __ATOMIC_ACQ_REL 4 234 #endif 235 #ifndef __ATOMIC_SEQ_CST 236 #define __ATOMIC_SEQ_CST 5 237 #endif 238 239 /* 240 * 7.17.3 Order and consistency. 241 * 242 * The memory_order_* constants that denote the barrier behaviour of the 243 * atomic operations. 244 * The enum values must be identical to those used by the 245 * C++ <atomic> header. 246 */ 247 248 typedef enum { 249 memory_order_relaxed = __ATOMIC_RELAXED, 250 memory_order_consume = __ATOMIC_CONSUME, 251 memory_order_acquire = __ATOMIC_ACQUIRE, 252 memory_order_release = __ATOMIC_RELEASE, 253 memory_order_acq_rel = __ATOMIC_ACQ_REL, 254 memory_order_seq_cst = __ATOMIC_SEQ_CST 255 } memory_order; 256 257 /* 258 * 7.17.4 Fences. 259 */ 260 261 static __inline void 262 atomic_thread_fence(memory_order __order __attribute__((unused))) 263 { 264 265 #ifdef __CLANG_ATOMICS 266 __c11_atomic_thread_fence(__order); 267 #elif defined(__GNUC_ATOMICS) 268 __atomic_thread_fence(__order); 269 #else 270 __sync_synchronize(); 271 #endif 272 } 273 274 static __inline void 275 atomic_signal_fence(memory_order __order __attribute__((unused))) 276 { 277 278 #ifdef __CLANG_ATOMICS 279 __c11_atomic_signal_fence(__order); 280 #elif defined(__GNUC_ATOMICS) 281 __atomic_signal_fence(__order); 282 #else 283 __asm volatile ("" ::: "memory"); 284 #endif 285 } 286 287 /* 288 * 7.17.5 Lock-free property. 289 */ 290 291 #if defined(_KERNEL) 292 /* Atomics in kernelspace are always lock-free. */ 293 #define atomic_is_lock_free(obj) \ 294 ((void)(obj), (_Bool)1) 295 #elif defined(__CLANG_ATOMICS) 296 #define atomic_is_lock_free(obj) \ 297 __c11_atomic_is_lock_free(sizeof(*(obj))) 298 #elif defined(__GNUC_ATOMICS) 299 #define atomic_is_lock_free(obj) \ 300 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) 301 #else 302 #define atomic_is_lock_free(obj) \ 303 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 304 #endif 305 306 /* 307 * 7.17.6 Atomic integer types. 308 */ 309 310 #ifndef __CLANG_ATOMICS 311 /* 312 * No native support for _Atomic(). Place object in structure to prevent 313 * most forms of direct non-atomic access. 314 */ 315 #define _Atomic(T) struct { T volatile __val; } 316 #endif 317 318 typedef _Atomic(bool) atomic_bool; 319 typedef _Atomic(char) atomic_char; 320 typedef _Atomic(signed char) atomic_schar; 321 typedef _Atomic(unsigned char) atomic_uchar; 322 typedef _Atomic(short) atomic_short; 323 typedef _Atomic(unsigned short) atomic_ushort; 324 typedef _Atomic(int) atomic_int; 325 typedef _Atomic(unsigned int) atomic_uint; 326 typedef _Atomic(long) atomic_long; 327 typedef _Atomic(unsigned long) atomic_ulong; 328 typedef _Atomic(long long) atomic_llong; 329 typedef _Atomic(unsigned long long) atomic_ullong; 330 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L 331 typedef _Atomic(char16_t) atomic_char16_t; 332 typedef _Atomic(char32_t) atomic_char32_t; 333 #endif 334 typedef _Atomic(wchar_t) atomic_wchar_t; 335 typedef _Atomic(int_least8_t) atomic_int_least8_t; 336 typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 337 typedef _Atomic(int_least16_t) atomic_int_least16_t; 338 typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 339 typedef _Atomic(int_least32_t) atomic_int_least32_t; 340 typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 341 typedef _Atomic(int_least64_t) atomic_int_least64_t; 342 typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 343 typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 344 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 345 typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 346 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 347 typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 348 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 349 typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 350 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 351 typedef _Atomic(intptr_t) atomic_intptr_t; 352 typedef _Atomic(uintptr_t) atomic_uintptr_t; 353 typedef _Atomic(size_t) atomic_size_t; 354 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 355 typedef _Atomic(intmax_t) atomic_intmax_t; 356 typedef _Atomic(uintmax_t) atomic_uintmax_t; 357 358 /* 359 * 7.17.7 Operations on atomic types. 360 */ 361 362 /* 363 * Compiler-specific operations. 364 */ 365 366 #if defined(__CLANG_ATOMICS) 367 #define atomic_compare_exchange_strong_explicit(object, expected, \ 368 desired, success, failure) \ 369 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 370 success, failure) 371 #define atomic_compare_exchange_weak_explicit(object, expected, \ 372 desired, success, failure) \ 373 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 374 success, failure) 375 #define atomic_exchange_explicit(object, desired, order) \ 376 __c11_atomic_exchange(object, desired, order) 377 #define atomic_fetch_add_explicit(object, operand, order) \ 378 __c11_atomic_fetch_add(object, operand, order) 379 #define atomic_fetch_and_explicit(object, operand, order) \ 380 __c11_atomic_fetch_and(object, operand, order) 381 #define atomic_fetch_or_explicit(object, operand, order) \ 382 __c11_atomic_fetch_or(object, operand, order) 383 #define atomic_fetch_sub_explicit(object, operand, order) \ 384 __c11_atomic_fetch_sub(object, operand, order) 385 #define atomic_fetch_xor_explicit(object, operand, order) \ 386 __c11_atomic_fetch_xor(object, operand, order) 387 #define atomic_load_explicit(object, order) \ 388 __c11_atomic_load(object, order) 389 #define atomic_store_explicit(object, desired, order) \ 390 __c11_atomic_store(object, desired, order) 391 #elif defined(__GNUC_ATOMICS) 392 #define atomic_compare_exchange_strong_explicit(object, expected, \ 393 desired, success, failure) \ 394 __atomic_compare_exchange_n(&(object)->__val, expected, \ 395 desired, 0, success, failure) 396 #define atomic_compare_exchange_weak_explicit(object, expected, \ 397 desired, success, failure) \ 398 __atomic_compare_exchange_n(&(object)->__val, expected, \ 399 desired, 1, success, failure) 400 #define atomic_exchange_explicit(object, desired, order) \ 401 __atomic_exchange_n(&(object)->__val, desired, order) 402 #define atomic_fetch_add_explicit(object, operand, order) \ 403 __atomic_fetch_add(&(object)->__val, operand, order) 404 #define atomic_fetch_and_explicit(object, operand, order) \ 405 __atomic_fetch_and(&(object)->__val, operand, order) 406 #define atomic_fetch_or_explicit(object, operand, order) \ 407 __atomic_fetch_or(&(object)->__val, operand, order) 408 #define atomic_fetch_sub_explicit(object, operand, order) \ 409 __atomic_fetch_sub(&(object)->__val, operand, order) 410 #define atomic_fetch_xor_explicit(object, operand, order) \ 411 __atomic_fetch_xor(&(object)->__val, operand, order) 412 #define atomic_load_explicit(object, order) \ 413 __atomic_load_n(&(object)->__val, order) 414 #define atomic_store_explicit(object, desired, order) \ 415 __atomic_store_n(&(object)->__val, desired, order) 416 #else 417 #define __atomic_apply_stride(object, operand) \ 418 (((__typeof__((object)->__val))0) + (operand)) 419 #define atomic_compare_exchange_strong_explicit(object, expected, \ 420 desired, success, failure) __extension__ ({ \ 421 __typeof__(expected) __ep = (expected); \ 422 __typeof__(*__ep) __e = *__ep; \ 423 (void)(success); (void)(failure); \ 424 (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 425 __e, desired)) == __e); \ 426 }) 427 #define atomic_compare_exchange_weak_explicit(object, expected, \ 428 desired, success, failure) \ 429 atomic_compare_exchange_strong_explicit(object, expected, \ 430 desired, success, failure) 431 #ifdef __HAS_BUILTIN_SYNC_SWAP 432 /* Clang provides a full-barrier atomic exchange - use it if available. */ 433 #define atomic_exchange_explicit(object, desired, order) \ 434 ((void)(order), __sync_swap(&(object)->__val, desired)) 435 #else 436 /* 437 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 438 * practice it is usually a full barrier) so we need an explicit barrier before 439 * it. 440 */ 441 #define atomic_exchange_explicit(object, desired, order) \ 442 __extension__ ({ \ 443 __typeof__(object) __o = (object); \ 444 __typeof__(desired) __d = (desired); \ 445 (void)(order); \ 446 __sync_synchronize(); \ 447 __sync_lock_test_and_set(&(__o)->__val, __d); \ 448 }) 449 #endif 450 #define atomic_fetch_add_explicit(object, operand, order) \ 451 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 452 __atomic_apply_stride(object, operand))) 453 #define atomic_fetch_and_explicit(object, operand, order) \ 454 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 455 #define atomic_fetch_or_explicit(object, operand, order) \ 456 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 457 #define atomic_fetch_sub_explicit(object, operand, order) \ 458 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 459 __atomic_apply_stride(object, operand))) 460 #define atomic_fetch_xor_explicit(object, operand, order) \ 461 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 462 #define atomic_load_explicit(object, order) \ 463 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 464 #define atomic_store_explicit(object, desired, order) \ 465 ((void)atomic_exchange_explicit(object, desired, order)) 466 #endif 467 468 /* 469 * Convenience functions. 470 * 471 * Don't provide these in kernel space. In kernel space, we should be 472 * disciplined enough to always provide explicit barriers. 473 */ 474 475 #ifndef _KERNEL 476 #define atomic_compare_exchange_strong(object, expected, desired) \ 477 atomic_compare_exchange_strong_explicit(object, expected, \ 478 desired, memory_order_seq_cst, memory_order_seq_cst) 479 #define atomic_compare_exchange_weak(object, expected, desired) \ 480 atomic_compare_exchange_weak_explicit(object, expected, \ 481 desired, memory_order_seq_cst, memory_order_seq_cst) 482 #define atomic_exchange(object, desired) \ 483 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 484 #define atomic_fetch_add(object, operand) \ 485 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 486 #define atomic_fetch_and(object, operand) \ 487 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 488 #define atomic_fetch_or(object, operand) \ 489 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 490 #define atomic_fetch_sub(object, operand) \ 491 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 492 #define atomic_fetch_xor(object, operand) \ 493 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 494 #define atomic_load(object) \ 495 atomic_load_explicit(object, memory_order_seq_cst) 496 #define atomic_store(object, desired) \ 497 atomic_store_explicit(object, desired, memory_order_seq_cst) 498 #endif /* !_KERNEL */ 499 500 /* 501 * 7.17.8 Atomic flag type and operations. 502 * 503 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 504 * kind of compiler built-in type we could use? 505 */ 506 507 typedef struct { 508 atomic_bool __flag; 509 } atomic_flag; 510 511 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 512 513 static __inline bool 514 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 515 memory_order __order) 516 { 517 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 518 } 519 520 static __inline void 521 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 522 { 523 524 atomic_store_explicit(&__object->__flag, 0, __order); 525 } 526 527 #ifndef _KERNEL 528 static __inline bool 529 atomic_flag_test_and_set(volatile atomic_flag *__object) 530 { 531 532 return (atomic_flag_test_and_set_explicit(__object, 533 memory_order_seq_cst)); 534 } 535 536 static __inline void 537 atomic_flag_clear(volatile atomic_flag *__object) 538 { 539 540 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 541 } 542 #endif /* !_KERNEL */ 543 544 #endif /* <atomic> unavailable */ 545 546 #endif /* !_STDATOMIC_H_ */ 547
