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 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_ */