lib/frratomic.h

   1 // SPDX-License-Identifier: ISC
   2 /*
   3  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   4  */
   5
   6 #ifndef _FRRATOMIC_H
   7 #define _FRRATOMIC_H
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include "config.h"
  11 #endif
  12
  13 #ifndef FRR_AUTOCONF_ATOMIC
  14 #error autoconf checks for atomic functions were not properly run
  15 #endif
  16
  17 /* ISO C11 */
  18 #ifdef __cplusplus
  19 #include <stdint.h>
  20 #include <atomic>
  21 using std::atomic_int;
  22 using std::memory_order;
  23 using std::memory_order_relaxed;
  24 using std::memory_order_acquire;
  25 using std::memory_order_release;
  26 using std::memory_order_acq_rel;
  27 using std::memory_order_consume;
  28 using std::memory_order_seq_cst;
  29
  30 typedef std::atomic<bool>               atomic_bool;
  31 typedef std::atomic<size_t>             atomic_size_t;
  32 typedef std::atomic<uint_fast32_t>      atomic_uint_fast32_t;
  33 typedef std::atomic<uintptr_t>          atomic_uintptr_t;
  34
  35 #elif defined(HAVE_STDATOMIC_H)
  36 #include <stdatomic.h>
  37
  38 /* These are available in gcc, but not in stdatomic */
  39 #define atomic_add_fetch_explicit __atomic_add_fetch
  40 #define atomic_sub_fetch_explicit __atomic_sub_fetch
  41 #define atomic_and_fetch_explicit __atomic_and_fetch
  42 #define atomic_or_fetch_explicit __atomic_or_fetch
  43
  44 /* gcc 4.7 and newer */
  45 #elif defined(HAVE___ATOMIC)
  46
  47 #define _Atomic volatile
  48 #define _ATOMIC_WANT_TYPEDEFS
  49
  50 #define memory_order_relaxed __ATOMIC_RELAXED
  51 #define memory_order_consume __ATOMIC_CONSUME
  52 #define memory_order_acquire __ATOMIC_ACQUIRE
  53 #define memory_order_release __ATOMIC_RELEASE
  54 #define memory_order_acq_rel __ATOMIC_ACQ_REL
  55 #define memory_order_seq_cst __ATOMIC_SEQ_CST
  56
  57 #define atomic_load_explicit __atomic_load_n
  58 #define atomic_store_explicit __atomic_store_n
  59 #define atomic_exchange_explicit __atomic_exchange_n
  60 #define atomic_fetch_add_explicit __atomic_fetch_add
  61 #define atomic_fetch_sub_explicit __atomic_fetch_sub
  62 #define atomic_fetch_and_explicit __atomic_fetch_and
  63 #define atomic_fetch_or_explicit __atomic_fetch_or
  64
  65 #define atomic_add_fetch_explicit __atomic_add_fetch
  66 #define atomic_sub_fetch_explicit __atomic_sub_fetch
  67 #define atomic_and_fetch_explicit __atomic_and_fetch
  68 #define atomic_or_fetch_explicit __atomic_or_fetch
  69
  70 #define atomic_compare_exchange_weak_explicit(atom, expect, desire, mem1,      \
  71                                               mem2)                            \
  72         __atomic_compare_exchange_n(atom, expect, desire, 1, mem1, mem2)
  73 #define atomic_compare_exchange_strong_explicit(atom, expect, desire, mem1,    \
  74                                               mem2)                            \
  75         __atomic_compare_exchange_n(atom, expect, desire, 0, mem1, mem2)
  76
  77 /* gcc 4.1 and newer,
  78  * clang 3.3 (possibly older)
  79  *
  80  * __sync_swap isn't in gcc's documentation, but clang has it
  81  *
  82  * note __sync_synchronize()
  83  */
  84 #elif defined(HAVE___SYNC)
  85
  86 #define _Atomic volatile
  87 #define _ATOMIC_WANT_TYPEDEFS
  88
  89 #define memory_order_relaxed 0
  90 #define memory_order_consume 0
  91 #define memory_order_acquire 0
  92 #define memory_order_release 0
  93 #define memory_order_acq_rel 0
  94 #define memory_order_seq_cst 0
  95
  96 #define atomic_load_explicit(ptr, mem)                                         \
  97         ({                                                                     \
  98                 __sync_synchronize();                                          \
  99                 typeof(*ptr) rval = __sync_fetch_and_add((ptr), 0);            \
 100                 __sync_synchronize();                                          \
 101                 rval;                                                          \
 102         })
 103 #define atomic_store_explicit(ptr, val, mem)                                   \
 104         ({                                                                     \
 105                 __sync_synchronize();                                          \
 106                 *(ptr) = (val);                                                \
 107                 __sync_synchronize();                                          \
 108                 (void)0;                                                       \
 109         })
 110 #ifdef HAVE___SYNC_SWAP
 111 #define atomic_exchange_explicit(ptr, val, mem)                                \
 112         ({                                                                     \
 113                 __sync_synchronize();                                          \
 114                 typeof(*ptr) rval = __sync_swap((ptr, val), 0);                \
 115                 __sync_synchronize();                                          \
 116                 rval;                                                          \
 117         })
 118 #else /* !HAVE___SYNC_SWAP */
 119 #define atomic_exchange_explicit(ptr, val, mem)                                \
 120         ({                                                                     \
 121                 typeof(ptr) _ptr = (ptr);                                      \
 122                 typeof(val) _val = (val);                                      \
 123                 __sync_synchronize();                                          \
 124                 typeof(*ptr) old1, old2 = __sync_fetch_and_add(_ptr, 0);       \
 125                 do {                                                           \
 126                         old1 = old2;                                           \
 127                         old2 = __sync_val_compare_and_swap(_ptr, old1, _val);  \
 128                 } while (old1 != old2);                                        \
 129                 __sync_synchronize();                                          \
 130                 old2;                                                          \
 131         })
 132 #endif /* !HAVE___SYNC_SWAP */
 133 #define atomic_fetch_add_explicit(ptr, val, mem)                               \
 134         ({                                                                     \
 135                 __sync_synchronize();                                          \
 136                 typeof(*ptr) rval = __sync_fetch_and_add((ptr), (val));        \
 137                 __sync_synchronize();                                          \
 138                 rval;                                                          \
 139         })
 140 #define atomic_fetch_sub_explicit(ptr, val, mem)                               \
 141         ({                                                                     \
 142                 __sync_synchronize();                                          \
 143                 typeof(*ptr) rval = __sync_fetch_and_sub((ptr), (val));        \
 144                 __sync_synchronize();                                          \
 145                 rval;                                                          \
 146         })
 147
 148 #define atomic_compare_exchange_strong_explicit(atom, expect, desire, mem1,    \
 149                                               mem2)                            \
 150         ({                                                                     \
 151                 typeof(atom) _atom = (atom);                                   \
 152                 typeof(expect) _expect = (expect);                             \
 153                 typeof(desire) _desire = (desire);                             \
 154                 __sync_synchronize();                                          \
 155                 typeof(*atom) rval =                                           \
 156                         __sync_val_compare_and_swap(_atom, *_expect, _desire); \
 157                 __sync_synchronize();                                          \
 158                 bool ret = (rval == *_expect);                                 \
 159                 *_expect = rval;                                               \
 160                 ret;                                                           \
 161         })
 162 #define atomic_compare_exchange_weak_explicit \
 163         atomic_compare_exchange_strong_explicit
 164
 165 #define atomic_fetch_and_explicit(ptr, val, mem)                               \
 166         ({                                                                     \
 167                 __sync_synchronize();                                          \
 168                 typeof(*ptr) rval = __sync_fetch_and_and(ptr, val);            \
 169                 __sync_synchronize();                                          \
 170                 rval;                                                          \
 171         })
 172 #define atomic_fetch_or_explicit(ptr, val, mem)                                \
 173         ({                                                                     \
 174                 __sync_synchronize();                                          \
 175                 typeof(*ptr) rval = __sync_fetch_and_or(ptr, val);             \
 176                 __sync_synchronize();                                          \
 177                 rval;                                                          \
 178         })
 179
 180 #define atomic_add_fetch_explicit(ptr, val, mem)                               \
 181         ({                                                                     \
 182                 __sync_synchronize();                                          \
 183                 typeof(*ptr) rval = __sync_add_and_fetch((ptr), (val));        \
 184                 __sync_synchronize();                                          \
 185                 rval;                                                          \
 186         })
 187 #define atomic_sub_fetch_explicit(ptr, val, mem)                               \
 188         ({                                                                     \
 189                 __sync_synchronize();                                          \
 190                 typeof(*ptr) rval = __sync_sub_and_fetch((ptr), (val));        \
 191                 __sync_synchronize();                                          \
 192                 rval;                                                          \
 193         })
 194
 195 #define atomic_and_fetch_explicit(ptr, val, mem)                               \
 196         ({                                                                     \
 197                 __sync_synchronize();                                          \
 198                 typeof(*ptr) rval = __sync_and_and_fetch(ptr, val);            \
 199                 __sync_synchronize();                                          \
 200                 rval;                                                          \
 201         })
 202 #define atomic_or_fetch_explicit(ptr, val, mem)                                \
 203         ({                                                                     \
 204                 __sync_synchronize();                                          \
 205                 typeof(*ptr) rval = __sync_or_and_fetch(ptr, val);             \
 206                 __sync_synchronize();                                          \
 207                 rval;                                                          \
 208         })
 209
 210 #else /* !HAVE___ATOMIC && !HAVE_STDATOMIC_H */
 211 #error no atomic functions...
 212 #endif
 213
 214 #ifdef _ATOMIC_WANT_TYPEDEFS
 215 #undef _ATOMIC_WANT_TYPEDEFS
 216
 217 #include <stdint.h>
 218 #include <stdbool.h>
 219
 220 typedef _Atomic bool            atomic_bool;
 221 typedef _Atomic size_t          atomic_size_t;
 222 typedef _Atomic uint_fast32_t   atomic_uint_fast32_t;
 223 typedef _Atomic uintptr_t       atomic_uintptr_t;
 224 #endif
 225
 226 #endif /* _FRRATOMIC_H */