sys/sys/stdatomic.h

   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 enum memory_order {
 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 };
 133
 134 /*
 135  * 7.17.4 Fences.
 136  */
 137
 138 #ifdef __CLANG_ATOMICS
 139 #define atomic_thread_fence(order)      __c11_atomic_thread_fence(order)
 140 #define atomic_signal_fence(order)      __c11_atomic_signal_fence(order)
 141 #elif defined(__GNUC_ATOMICS)
 142 #define atomic_thread_fence(order)      __atomic_thread_fence(order)
 143 #define atomic_signal_fence(order)      __atomic_signal_fence(order)
 144 #else
 145 #define atomic_thread_fence(order)      ((void)(order), __sync_synchronize())
 146 #define atomic_signal_fence(order)      __extension__ ({                \
 147         (void)(order);                                                  \
 148         __asm volatile ("" ::: "memory");                               \
 149         (void)0;                                                        \
 150 })
 151 #endif
 152
 153 /*
 154  * 7.17.5 Lock-free property.
 155  */
 156
 157 #if defined(_KERNEL)
 158 /* Atomics in kernelspace are always lock-free. */
 159 #define atomic_is_lock_free(obj) \
 160         ((void)(obj), (_Bool)1)
 161 #elif defined(__CLANG_ATOMICS)
 162 #define atomic_is_lock_free(obj) \
 163         __atomic_is_lock_free(sizeof(*(obj)), obj)
 164 #elif defined(__GNUC_ATOMICS)
 165 #define atomic_is_lock_free(obj) \
 166         __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
 167 #else
 168 #define atomic_is_lock_free(obj) \
 169         ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
 170 #endif
 171
 172 /*
 173  * 7.17.6 Atomic integer types.
 174  */
 175
 176 typedef _Atomic(_Bool)                  atomic_bool;
 177 typedef _Atomic(char)                   atomic_char;
 178 typedef _Atomic(signed char)            atomic_schar;
 179 typedef _Atomic(unsigned char)          atomic_uchar;
 180 typedef _Atomic(short)                  atomic_short;
 181 typedef _Atomic(unsigned short)         atomic_ushort;
 182 typedef _Atomic(int)                    atomic_int;
 183 typedef _Atomic(unsigned int)           atomic_uint;
 184 typedef _Atomic(long)                   atomic_long;
 185 typedef _Atomic(unsigned long)          atomic_ulong;
 186 typedef _Atomic(long long)              atomic_llong;
 187 typedef _Atomic(unsigned long long)     atomic_ullong;
 188 typedef _Atomic(__char16_t)             atomic_char16_t;
 189 typedef _Atomic(__char32_t)             atomic_char32_t;
 190 typedef _Atomic(__wchar_t)              atomic_wchar_t;
 191 typedef _Atomic(__int_least8_t)         atomic_int_least8_t;
 192 typedef _Atomic(__uint_least8_t)        atomic_uint_least8_t;
 193 typedef _Atomic(__int_least16_t)        atomic_int_least16_t;
 194 typedef _Atomic(__uint_least16_t)       atomic_uint_least16_t;
 195 typedef _Atomic(__int_least32_t)        atomic_int_least32_t;
 196 typedef _Atomic(__uint_least32_t)       atomic_uint_least32_t;
 197 typedef _Atomic(__int_least64_t)        atomic_int_least64_t;
 198 typedef _Atomic(__uint_least64_t)       atomic_uint_least64_t;
 199 typedef _Atomic(__int_fast8_t)          atomic_int_fast8_t;
 200 typedef _Atomic(__uint_fast8_t)         atomic_uint_fast8_t;
 201 typedef _Atomic(__int_fast16_t)         atomic_int_fast16_t;
 202 typedef _Atomic(__uint_fast16_t)        atomic_uint_fast16_t;
 203 typedef _Atomic(__int_fast32_t)         atomic_int_fast32_t;
 204 typedef _Atomic(__uint_fast32_t)        atomic_uint_fast32_t;
 205 typedef _Atomic(__int_fast64_t)         atomic_int_fast64_t;
 206 typedef _Atomic(__uint_fast64_t)        atomic_uint_fast64_t;
 207 typedef _Atomic(__intptr_t)             atomic_intptr_t;
 208 typedef _Atomic(__uintptr_t)            atomic_uintptr_t;
 209 typedef _Atomic(__size_t)               atomic_size_t;
 210 typedef _Atomic(__ptrdiff_t)            atomic_ptrdiff_t;
 211 typedef _Atomic(__intmax_t)             atomic_intmax_t;
 212 typedef _Atomic(__uintmax_t)            atomic_uintmax_t;
 213
 214 /*
 215  * 7.17.7 Operations on atomic types.
 216  */
 217
 218 /*
 219  * Compiler-specific operations.
 220  */
 221
 222 #if defined(__CLANG_ATOMICS)
 223 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 224     desired, success, failure)                                          \
 225         __c11_atomic_compare_exchange_strong(object, expected, desired, \
 226             success, failure)
 227 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 228     desired, success, failure)                                          \
 229         __c11_atomic_compare_exchange_weak(object, expected, desired,   \
 230             success, failure)
 231 #define atomic_exchange_explicit(object, desired, order)                \
 232         __c11_atomic_exchange(object, desired, order)
 233 #define atomic_fetch_add_explicit(object, operand, order)               \
 234         __c11_atomic_fetch_add(object, operand, order)
 235 #define atomic_fetch_and_explicit(object, operand, order)               \
 236         __c11_atomic_fetch_and(object, operand, order)
 237 #define atomic_fetch_or_explicit(object, operand, order)                \
 238         __c11_atomic_fetch_or(object, operand, order)
 239 #define atomic_fetch_sub_explicit(object, operand, order)               \
 240         __c11_atomic_fetch_sub(object, operand, order)
 241 #define atomic_fetch_xor_explicit(object, operand, order)               \
 242         __c11_atomic_fetch_xor(object, operand, order)
 243 #define atomic_load_explicit(object, order)                             \
 244         __c11_atomic_load(object, order)
 245 #define atomic_store_explicit(object, desired, order)                   \
 246         __c11_atomic_store(object, desired, order)
 247 #elif defined(__GNUC_ATOMICS)
 248 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 249     desired, success, failure)                                          \
 250         __atomic_compare_exchange_n(&(object)->__val, expected,         \
 251             desired, 0, success, failure)
 252 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 253     desired, success, failure)                                          \
 254         __atomic_compare_exchange_n(&(object)->__val, expected,         \
 255             desired, 1, success, failure)
 256 #define atomic_exchange_explicit(object, desired, order)                \
 257         __atomic_exchange_n(&(object)->__val, desired, order)
 258 #define atomic_fetch_add_explicit(object, operand, order)               \
 259         __atomic_fetch_add(&(object)->__val, operand, order)
 260 #define atomic_fetch_and_explicit(object, operand, order)               \
 261         __atomic_fetch_and(&(object)->__val, operand, order)
 262 #define atomic_fetch_or_explicit(object, operand, order)                \
 263         __atomic_fetch_or(&(object)->__val, operand, order)
 264 #define atomic_fetch_sub_explicit(object, operand, order)               \
 265         __atomic_fetch_sub(&(object)->__val, operand, order)
 266 #define atomic_fetch_xor_explicit(object, operand, order)               \
 267         __atomic_fetch_xor(&(object)->__val, operand, order)
 268 #define atomic_load_explicit(object, order)                             \
 269         __atomic_load_n(&(object)->__val, order)
 270 #define atomic_store_explicit(object, desired, order)                   \
 271         __atomic_store_n(&(object)->__val, desired, order)
 272 #else
 273 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 274     desired, success, failure)  __extension__ ({                        \
 275         __typeof__(expected) __ep = (expected);                         \
 276         __typeof__(*__ep) __e = *__ep;                                  \
 277         (void)(success); (void)(failure);                               \
 278         (*__ep = __sync_val_compare_and_swap(&(object)->__val,          \
 279             __e, desired)) == __e;                                      \
 280 })
 281 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 282     desired, success, failure)                                          \
 283         atomic_compare_exchange_strong_explicit(object, expected,       \
 284                 desired, success, failure)
 285 #if __has_builtin(__sync_swap)
 286 /* Clang provides a full-barrier atomic exchange - use it if available. */
 287 #define atomic_exchange_explicit(object, desired, order)                \
 288         ((void)(order), __sync_swap(&(object)->__val, desired))
 289 #else
 290 /*
 291  * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
 292  * practice it is usually a full barrier) so we need an explicit barrier before
 293  * it.
 294  */
 295 #define atomic_exchange_explicit(object, desired, order)                \
 296 __extension__ ({                                                        \
 297         __typeof__(object) __o = (object);                              \
 298         __typeof__(desired) __d = (desired);                            \
 299         (void)(order);                                                  \
 300         __sync_synchronize();                                           \
 301         __sync_lock_test_and_set(&(__o)->__val, __d);                   \
 302 })
 303 #endif
 304 #define atomic_fetch_add_explicit(object, operand, order)               \
 305         ((void)(order), __sync_fetch_and_add(&(object)->__val, operand))
 306 #define atomic_fetch_and_explicit(object, operand, order)               \
 307         ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
 308 #define atomic_fetch_or_explicit(object, operand, order)                \
 309         ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
 310 #define atomic_fetch_sub_explicit(object, operand, order)               \
 311         ((void)(order), __sync_fetch_and_sub(&(object)->__val, operand))
 312 #define atomic_fetch_xor_explicit(object, operand, order)               \
 313         ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
 314 #define atomic_load_explicit(object, order)                             \
 315         ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
 316 #define atomic_store_explicit(object, desired, order)                   \
 317         ((void)atomic_exchange_explicit(object, desired, order))
 318 #endif
 319
 320 /*
 321  * Convenience functions.
 322  */
 323
 324 #define atomic_compare_exchange_strong(object, expected, desired)       \
 325         atomic_compare_exchange_strong_explicit(object, expected,       \
 326             desired, memory_order_seq_cst, memory_order_seq_cst)
 327 #define atomic_compare_exchange_weak(object, expected, desired)         \
 328         atomic_compare_exchange_weak_explicit(object, expected,         \
 329             desired, memory_order_seq_cst, memory_order_seq_cst)
 330 #define atomic_exchange(object, desired)                                \
 331         atomic_exchange_explicit(object, desired, memory_order_seq_cst)
 332 #define atomic_fetch_add(object, operand)                               \
 333         atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
 334 #define atomic_fetch_and(object, operand)                               \
 335         atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
 336 #define atomic_fetch_or(object, operand)                                \
 337         atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
 338 #define atomic_fetch_sub(object, operand)                               \
 339         atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
 340 #define atomic_fetch_xor(object, operand)                               \
 341         atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
 342 #define atomic_load(object)                                             \
 343         atomic_load_explicit(object, memory_order_seq_cst)
 344 #define atomic_store(object, desired)                                   \
 345         atomic_store_explicit(object, desired, memory_order_seq_cst)
 346
 347 /*
 348  * 7.17.8 Atomic flag type and operations.
 349  */
 350
 351 typedef atomic_bool                     atomic_flag;
 352
 353 #define ATOMIC_FLAG_INIT                ATOMIC_VAR_INIT(0)
 354
 355 #define atomic_flag_clear_explicit(object, order)                       \
 356         atomic_store_explicit(object, 0, order)
 357 #define atomic_flag_test_and_set_explicit(object, order)                \
 358         atomic_compare_exchange_strong_explicit(object, 0, 1, order, order)
 359
 360 #define atomic_flag_clear(object)                                       \
 361         atomic_flag_clear_explicit(object, memory_order_seq_cst)
 362 #define atomic_flag_test_and_set(object)                                \
 363         atomic_flag_test_and_set_explicit(object, memory_order_seq_cst)
 364
 365 #endif /* !_STDATOMIC_H_ */