osfmk/i386/atomic.h

   1 /*
   2  * Copyright (c) 2015 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  23  * Please see the License for the specific language governing rights and
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  27  */
  28
  29 #ifndef _I386_ATOMIC_H_
  30 #define _I386_ATOMIC_H_
  31
  32 #include <i386/smp.h>
  33
  34 #if     __SMP__
  35
  36 #define memory_order_consume_smp memory_order_consume
  37 #define memory_order_acquire_smp memory_order_acquire
  38 #define memory_order_release_smp memory_order_release
  39 #define memory_order_acq_rel_smp memory_order_acq_rel
  40 #define memory_order_seq_cst_smp memory_order_seq_cst
  41
  42 #else
  43
  44 #define memory_order_consume_smp memory_order_relaxed
  45 #define memory_order_acquire_smp memory_order_relaxed
  46 #define memory_order_release_smp memory_order_relaxed
  47 #define memory_order_acq_rel_smp memory_order_relaxed
  48 #define memory_order_seq_cst_smp memory_order_relaxed
  49
  50 #endif
  51
  52 #ifdef ATOMIC_PRIVATE
  53
  54 static boolean_t
  55 atomic_compare_exchange(uintptr_t *target, uintptr_t oldval, uintptr_t newval,
  56                         enum memory_order ord, boolean_t wait)
  57 {
  58         (void)wait;
  59         return __c11_atomic_compare_exchange_strong((_Atomic uintptr_t *)target, &oldval, newval, ord, memory_order_relaxed);
  60 }
  61
  62 #endif // ATOMIC_PRIVATE
  63
  64 #define os_atomic_rmw_loop(p, ov, nv, m, ...)  ({ \
  65                 bool _result = false; \
  66                 typeof(p) _p = (p); \
  67                 ov = atomic_load_explicit(_p, memory_order_relaxed); \
  68                 do { \
  69                         __VA_ARGS__; \
  70                         typeof(ov) _r = (ov); \
  71                         _result = atomic_compare_exchange_weak_explicit(_p, &_r, nv, \
  72                                         memory_order_##m, memory_order_relaxed); \
  73                         (ov) = _r; \
  74                 } while (__builtin_expect(!_result, 0)); \
  75                 _result; \
  76         })
  77
  78 #define os_atomic_rmw_loop_give_up(expr) ({ expr; __builtin_trap(); })
  79
  80 #endif // _I386_ATOMIC_H_