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  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
  12  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
  13  *
  14  * Permission is hereby granted to use or copy this program
  15  * for any purpose,  provided the above notices are retained on all copies.
  16  * Permission to modify the code and to distribute modified code is granted,
  17  * provided the above notices are retained, and a notice that the code was
  18  * modified is included with the above copyright notice.
  19  */
  20
  21 #include <urcu/compiler.h>
  22 #include <urcu/arch.h>
  23
  24 /*
  25  * Identify a shared load. A smp_rmc() or smp_mc() should come before the load.
  26  */
  27 #define _LOAD_SHARED(p)        ACCESS_ONCE(p)
  28
  29 /*
  30  * Load a data from shared memory, doing a cache flush if required.
  31  */
  32 #define LOAD_SHARED(p)                  \
  33         ({                              \
  34                 smp_rmc();              \
  35                 _LOAD_SHARED(p);        \
  36         })
  37
  38 /*
  39  * Identify a shared store. A smp_wmc() or smp_mc() should follow the store.
  40  */
  41 #define _STORE_SHARED(x, v)     ({ ACCESS_ONCE(x) = (v); })
  42
  43 /*
  44  * Store v into x, where x is located in shared memory. Performs the required
  45  * cache flush after writing. Returns v.
  46  */
  47 #define STORE_SHARED(x, v)              \
  48         ({                              \
  49                 typeof(x) _v = _STORE_SHARED(x, v);     \
  50                 smp_wmc();              \
  51                 _v;                     \
  52         })
  53
  54 #endif /* _URCU_SYSTEM_H */