lib/frratomic.h

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _FRRATOMIC_H
  18 #define _FRRATOMIC_H
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #ifndef FRR_AUTOCONF_ATOMIC
  25 #error autoconf checks for atomic functions were not properly run
  26 #endif
  27
  28 /* ISO C11 */
  29 #ifdef HAVE_STDATOMIC_H
  30 #include <stdatomic.h>
  31
  32 /* gcc 4.7 and newer */
  33 #elif defined(HAVE___ATOMIC)
  34
  35 #define _Atomic volatile
  36
  37 #define memory_order_relaxed __ATOMIC_RELAXED
  38 #define memory_order_consume __ATOMIC_CONSUME
  39 #define memory_order_acquire __ATOMIC_ACQUIRE
  40 #define memory_order_release __ATOMIC_RELEASE
  41 #define memory_order_acq_rel __ATOMIC_ACQ_REL
  42 #define memory_order_seq_cst __ATOMIC_SEQ_CST
  43
  44 #define atomic_load_explicit __atomic_load_n
  45 #define atomic_store_explicit __atomic_store_n
  46 #define atomic_exchange_explicit __atomic_exchange_n
  47 #define atomic_fetch_add_explicit __atomic_fetch_add
  48 #define atomic_fetch_sub_explicit __atomic_fetch_sub
  49
  50 #define atomic_compare_exchange_weak_explicit(atom, expect, desire, mem1, mem2) \
  51         __atomic_compare_exchange_n(atom, expect, desire, 1, mem1, mem2)
  52
  53 /* gcc 4.1 and newer,
  54  * clang 3.3 (possibly older)
  55  *
  56  * __sync_swap isn't in gcc's documentation, but clang has it
  57  *
  58  * note __sync_synchronize()
  59  */
  60 #elif defined(HAVE___SYNC)
  61
  62 #define _Atomic volatile
  63
  64 #define memory_order_relaxed 0
  65 #define memory_order_consume 0
  66 #define memory_order_acquire 0
  67 #define memory_order_release 0
  68 #define memory_order_acq_rel 0
  69 #define memory_order_seq_cst 0
  70
  71 #define atomic_load_explicit(ptr, mem) \
  72         ({ __sync_synchronize(); \
  73            typeof(*ptr) rval = __sync_fetch_and_add((ptr), 0); \
  74            __sync_synchronize(); rval; })
  75 #define atomic_store_explicit(ptr, val, mem) \
  76         ({ __sync_synchronize(); \
  77            *(ptr) = (val); \
  78            __sync_synchronize(); (void)0; })
  79 #ifdef HAVE___SYNC_SWAP
  80 #define atomic_exchange_explicit(ptr, val, mem) \
  81         ({ __sync_synchronize(); \
  82            typeof(*ptr) rval = __sync_swap((ptr, val), 0); \
  83            __sync_synchronize(); rval; })
  84 #else /* !HAVE___SYNC_SWAP */
  85 #define atomic_exchange_explicit(ptr, val, mem) \
  86         ({ typeof(ptr) _ptr = (ptr); typeof(val) _val = (val); \
  87            __sync_synchronize(); \
  88            typeof(*ptr) old1, old2 = __sync_fetch_and_add(_ptr, 0); \
  89            do { \
  90                 old1 = old2; \
  91                 old2 = __sync_val_compare_and_swap (_ptr, old1, _val); \
  92            } while (old1 != old2); \
  93            __sync_synchronize(); \
  94            old2; \
  95         })
  96 #endif /* !HAVE___SYNC_SWAP */
  97 #define atomic_fetch_add_explicit(ptr, val, mem) \
  98         ({ __sync_synchronize(); \
  99            typeof(*ptr) rval = __sync_fetch_and_add((ptr), (val)); \
 100            __sync_synchronize(); rval; })
 101 #define atomic_fetch_sub_explicit(ptr, val, mem) \
 102         ({ __sync_synchronize(); \
 103            typeof(*ptr) rval = __sync_fetch_and_sub((ptr), (val)); \
 104            __sync_synchronize(); rval; })
 105
 106 #define atomic_compare_exchange_weak_explicit(atom, expect, desire, mem1, mem2) \
 107         ({ typeof(atom) _atom = (atom); typeof(expect) _expect = (expect); \
 108            typeof(desire) _desire = (desire); \
 109            __sync_synchronize(); \
 110            typeof(*atom) rval = __sync_val_compare_and_swap(_atom, *_expect, _desire); \
 111            __sync_synchronize(); \
 112            bool ret = (rval == *_expect); *_expect = rval; ret; })
 113
 114 #else /* !HAVE___ATOMIC && !HAVE_STDATOMIC_H */
 115 #error no atomic functions...
 116 #endif
 117
 118 #endif /* _FRRATOMIC_H */