include/urcu/system.h

   1 // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   2 //
   3 // SPDX-License-Identifier: MIT
   4
   5 #ifndef _URCU_SYSTEM_H
   6 #define _URCU_SYSTEM_H
   7
   8 /*
   9  * System definitions.
  10  */
  11
  12 #include <urcu/compiler.h>
  13 #include <urcu/arch.h>
  14
  15 /*
  16  * Identify a shared load. A cmm_smp_rmc() or cmm_smp_mc() should come
  17  * before the load.
  18  */
  19 #define _CMM_LOAD_SHARED(p)            CMM_ACCESS_ONCE(p)
  20
  21 /*
  22  * Load a data from shared memory, doing a cache flush if required.
  23  */
  24 #define CMM_LOAD_SHARED(p)                      \
  25         __extension__                   \
  26         ({                              \
  27                 cmm_smp_rmc();          \
  28                 _CMM_LOAD_SHARED(p);    \
  29         })
  30
  31 /*
  32  * Identify a shared store. A cmm_smp_wmc() or cmm_smp_mc() should
  33  * follow the store.
  34  */
  35 #define _CMM_STORE_SHARED(x, v) __extension__ ({ CMM_ACCESS_ONCE(x) = (v); })
  36
  37 /*
  38  * Store v into x, where x is located in shared memory. Performs the
  39  * required cache flush after writing. Returns v.
  40  */
  41 #define CMM_STORE_SHARED(x, v)                                          \
  42         __extension__                                                   \
  43         ({                                                              \
  44                 __typeof__(x) _v = _CMM_STORE_SHARED(x, v);             \
  45                 cmm_smp_wmc();                                          \
  46                 _v = _v;        /* Work around clang "unused result" */ \
  47         })
  48
  49 #endif /* _URCU_SYSTEM_H */