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,      \
  51                                               mem2)                            \
  52         __atomic_compare_exchange_n(atom, expect, desire, 1, mem1, mem2)
  53
  54 /* gcc 4.1 and newer,
  55  * clang 3.3 (possibly older)
  56  *
  57  * __sync_swap isn't in gcc's documentation, but clang has it
  58  *
  59  * note __sync_synchronize()
  60  */
  61 #elif defined(HAVE___SYNC)
  62
  63 #define _Atomic volatile
  64
  65 #define memory_order_relaxed 0
  66 #define memory_order_consume 0
  67 #define memory_order_acquire 0
  68 #define memory_order_release 0
  69 #define memory_order_acq_rel 0
  70 #define memory_order_seq_cst 0
  71
  72 #define atomic_load_explicit(ptr, mem)                                         \
  73         ({                                                                     \
  74                 __sync_synchronize();                                          \
  75                 typeof(*ptr) rval = __sync_fetch_and_add((ptr), 0);            \
  76                 __sync_synchronize();                                          \
  77                 rval;                                                          \
  78         })
  79 #define atomic_store_explicit(ptr, val, mem)                                   \
  80         ({                                                                     \
  81                 __sync_synchronize();                                          \
  82                 *(ptr) = (val);                                                \
  83                 __sync_synchronize();                                          \
  84                 (void)0;                                                       \
  85         })
  86 #ifdef HAVE___SYNC_SWAP
  87 #define atomic_exchange_explicit(ptr, val, mem)                                \
  88         ({                                                                     \
  89                 __sync_synchronize();                                          \
  90                 typeof(*ptr) rval = __sync_swap((ptr, val), 0);                \
  91                 __sync_synchronize();                                          \
  92                 rval;                                                          \
  93         })
  94 #else /* !HAVE___SYNC_SWAP */
  95 #define atomic_exchange_explicit(ptr, val, mem)                                \
  96         ({                                                                     \
  97                 typeof(ptr) _ptr = (ptr);                                      \
  98                 typeof(val) _val = (val);                                      \
  99                 __sync_synchronize();                                          \
 100                 typeof(*ptr) old1, old2 = __sync_fetch_and_add(_ptr, 0);       \
 101                 do {                                                           \
 102                         old1 = old2;                                           \
 103                         old2 = __sync_val_compare_and_swap(_ptr, old1, _val);  \
 104                 } while (old1 != old2);                                        \
 105                 __sync_synchronize();                                          \
 106                 old2;                                                          \
 107         })
 108 #endif /* !HAVE___SYNC_SWAP */
 109 #define atomic_fetch_add_explicit(ptr, val, mem)                               \
 110         ({                                                                     \
 111                 __sync_synchronize();                                          \
 112                 typeof(*ptr) rval = __sync_fetch_and_add((ptr), (val));        \
 113                 __sync_synchronize();                                          \
 114                 rval;                                                          \
 115         })
 116 #define atomic_fetch_sub_explicit(ptr, val, mem)                               \
 117         ({                                                                     \
 118                 __sync_synchronize();                                          \
 119                 typeof(*ptr) rval = __sync_fetch_and_sub((ptr), (val));        \
 120                 __sync_synchronize();                                          \
 121                 rval;                                                          \
 122         })
 123
 124 #define atomic_compare_exchange_weak_explicit(atom, expect, desire, mem1,      \
 125                                               mem2)                            \
 126         ({                                                                     \
 127                 typeof(atom) _atom = (atom);                                   \
 128                 typeof(expect) _expect = (expect);                             \
 129                 typeof(desire) _desire = (desire);                             \
 130                 __sync_synchronize();                                          \
 131                 typeof(*atom) rval =                                           \
 132                         __sync_val_compare_and_swap(_atom, *_expect, _desire); \
 133                 __sync_synchronize();                                          \
 134                 bool ret = (rval == *_expect);                                 \
 135                 *_expect = rval;                                               \
 136                 ret;                                                           \
 137         })
 138
 139 #else /* !HAVE___ATOMIC && !HAVE_STDATOMIC_H */
 140 #error no atomic functions...
 141 #endif
 142
 143 #endif /* _FRRATOMIC_H */