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 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 61using std::atomic_is_lock_free; 62using std::atomic_init; 63using std::atomic_store; 64using std::atomic_store_explicit; 65using std::atomic_load; 66using std::atomic_load_explicit; 67using std::atomic_exchange; 68using std::atomic_exchange_explicit; 69using std::atomic_compare_exchange_strong; 70using std::atomic_compare_exchange_strong_explicit; 71using std::atomic_compare_exchange_weak; 72using std::atomic_compare_exchange_weak_explicit; 73using std::atomic_fetch_add; 74using std::atomic_fetch_add_explicit; 75using std::atomic_fetch_sub; 76using std::atomic_fetch_sub_explicit; 77using std::atomic_fetch_or; 78using std::atomic_fetch_or_explicit; 79using std::atomic_fetch_xor; 80using std::atomic_fetch_xor_explicit; 81using std::atomic_fetch_and; 82using std::atomic_fetch_and_explicit; 83using std::atomic_thread_fence; 84using std::atomic_signal_fence; 85 86using std::memory_order; 87using std::memory_order_relaxed; 88using std::memory_order_consume; 89using std::memory_order_acquire; 90using std::memory_order_release; 91using std::memory_order_acq_rel; 92using std::memory_order_seq_cst; 93 94using std::atomic_bool; 95using std::atomic_char; 96using std::atomic_schar; 97using std::atomic_uchar; 98using std::atomic_short; 99using std::atomic_ushort; 100using std::atomic_int; 101using std::atomic_uint; 102using std::atomic_long; 103using std::atomic_ulong; 104using std::atomic_llong; 105using std::atomic_ullong; 106using std::atomic_char16_t; 107using std::atomic_char32_t; 108using std::atomic_wchar_t; 109using std::atomic_int_least8_t; 110using std::atomic_uint_least8_t; 111using std::atomic_int_least16_t; 112using std::atomic_uint_least16_t; 113using std::atomic_int_least32_t; 114using std::atomic_uint_least32_t; 115using std::atomic_int_least64_t; 116using std::atomic_uint_least64_t; 117using std::atomic_int_fast8_t; 118using std::atomic_uint_fast8_t; 119using std::atomic_int_fast16_t; 120using std::atomic_uint_fast16_t; 121using std::atomic_int_fast32_t; 122using std::atomic_uint_fast32_t; 123using std::atomic_int_fast64_t; 124using std::atomic_uint_fast64_t; 125using std::atomic_intptr_t; 126using std::atomic_uintptr_t; 127using std::atomic_size_t; 128using std::atomic_ptrdiff_t; 129using std::atomic_intmax_t; 130using 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 248typedef 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 261static __inline void 262atomic_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 274static __inline void 275atomic_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 318typedef _Atomic(bool) atomic_bool; 319typedef _Atomic(char) atomic_char; 320typedef _Atomic(signed char) atomic_schar; 321typedef _Atomic(unsigned char) atomic_uchar; 322typedef _Atomic(short) atomic_short; 323typedef _Atomic(unsigned short) atomic_ushort; 324typedef _Atomic(int) atomic_int; 325typedef _Atomic(unsigned int) atomic_uint; 326typedef _Atomic(long) atomic_long; 327typedef _Atomic(unsigned long) atomic_ulong; 328typedef _Atomic(long long) atomic_llong; 329typedef _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 334typedef _Atomic(wchar_t) atomic_wchar_t; 335typedef _Atomic(int_least8_t) atomic_int_least8_t; 336typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 337typedef _Atomic(int_least16_t) atomic_int_least16_t; 338typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 339typedef _Atomic(int_least32_t) atomic_int_least32_t; 340typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 341typedef _Atomic(int_least64_t) atomic_int_least64_t; 342typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 343typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 344typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 345typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 346typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 347typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 348typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 349typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 350typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 351typedef _Atomic(intptr_t) atomic_intptr_t; 352typedef _Atomic(uintptr_t) atomic_uintptr_t; 353typedef _Atomic(size_t) atomic_size_t; 354typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 355typedef _Atomic(intmax_t) atomic_intmax_t; 356typedef _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 507typedef struct { 508 atomic_bool __flag; 509} atomic_flag; 510 511#define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 512 513static __inline bool 514atomic_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 520static __inline void 521atomic_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 528static __inline bool 529atomic_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 536static __inline void 537atomic_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