urcu/system.h

   1 #ifndef _URCU_SYSTEM_H
   2 #define _URCU_SYSTEM_H
   3
   4 /*
   5  * system.h
   6  *
   7  * System definitions.
   8  *
   9  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  */
  21
  22 #include <urcu/compiler.h>
  23 #include <urcu/arch.h>
  24
  25 /*
  26  * Identify a shared load. A cmm_smp_rmc() or cmm_smp_mc() should come
  27  * before the load.
  28  */
  29 #define _CMM_LOAD_SHARED(p)            CMM_ACCESS_ONCE(p)
  30
  31 /*
  32  * Load a data from shared memory, doing a cache flush if required.
  33  */
  34 #define CMM_LOAD_SHARED(p)                      \
  35         __extension__                   \
  36         ({                              \
  37                 cmm_smp_rmc();          \
  38                 _CMM_LOAD_SHARED(p);    \
  39         })
  40
  41 /*
  42  * Identify a shared store. A cmm_smp_wmc() or cmm_smp_mc() should
  43  * follow the store.
  44  */
  45 #define _CMM_STORE_SHARED(x, v) __extension__ ({ CMM_ACCESS_ONCE(x) = (v); })
  46
  47 /*
  48  * Store v into x, where x is located in shared memory. Performs the
  49  * required cache flush after writing. Returns v.
  50  */
  51 #define CMM_STORE_SHARED(x, v)                                          \
  52         __extension__                                                   \
  53         ({                                                              \
  54                 __typeof__(x) _v = _CMM_STORE_SHARED(x, v);             \
  55                 cmm_smp_wmc();                                          \
  56                 _v = _v;        /* Work around clang "unused result" */ \
  57         })
  58
  59 #endif /* _URCU_SYSTEM_H */