urcu/arch_generic.h

   1 #ifndef _URCU_ARCH_GENERIC_H
   2 #define _URCU_ARCH_GENERIC_H
   3
   4 /*
   5  * arch_generic.h: common definitions for multiple architectures.
   6  *
   7  * Copyright (c) 2010 Paolo Bonzini <pbonzini@redhat.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include <urcu/compiler.h>
  25 #include <urcu/config.h>
  26
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31 #ifndef CACHE_LINE_SIZE
  32 #define CACHE_LINE_SIZE 64
  33 #endif
  34
  35 #if !defined(mc) && !defined(rmc) && !defined(wmc)
  36 #define CONFIG_HAVE_MEM_COHERENCY
  37 /*
  38  * Architectures with cache coherency must _not_ define mc/rmc/wmc.
  39  *
  40  * For them, mc/rmc/wmc are implemented with a * simple compiler barrier;
  41  * in addition, we provide defaults for mb (using GCC builtins) as well as
  42  * rmb and wmb (defaulting to mb).
  43  */
  44
  45 #ifndef mb
  46 #define mb()    __sync_synchronize()
  47 #endif
  48
  49 #ifndef rmb
  50 #define rmb()    mb()
  51 #endif
  52
  53 #ifndef wmb
  54 #define wmb()    mb()
  55 #endif
  56
  57 #define mc()     barrier()
  58 #define rmc()    barrier()
  59 #define wmc()    barrier()
  60 #else
  61 /*
  62  * Architectures without cache coherency need something like the following:
  63  *
  64  * #define mc()         arch_cache_flush()
  65  * #define rmc()        arch_cache_flush_read()
  66  * #define wmc()        arch_cache_flush_write()
  67  *
  68  * Of these, only mc is mandatory.  rmc and wmc default to mc.  mb/rmb/wmb
  69  * use these definitions by default:
  70  *
  71  * #define mb()         mc()
  72  * #define rmb()        rmc()
  73  * #define wmb()        wmc()
  74  */
  75
  76 #ifndef mb
  77 #define mb()    mc()
  78 #endif
  79
  80 #ifndef rmb
  81 #define rmb()    rmc()
  82 #endif
  83
  84 #ifndef wmb
  85 #define wmb()    wmc()
  86 #endif
  87
  88 #ifndef rmc
  89 #define rmc()    mc()
  90 #endif
  91
  92 #ifndef wmc
  93 #define wmc()    mc()
  94 #endif
  95 #endif
  96
  97 /* Nop everywhere except on alpha. */
  98 #ifndef read_barrier_depends
  99 #define read_barrier_depends()
 100 #endif
 101
 102 #ifdef CONFIG_RCU_SMP
 103 #define smp_mb()        mb()
 104 #define smp_rmb()       rmb()
 105 #define smp_wmb()       wmb()
 106 #define smp_mc()        mc()
 107 #define smp_rmc()       rmc()
 108 #define smp_wmc()       wmc()
 109 #define smp_read_barrier_depends()      read_barrier_depends()
 110 #else
 111 #define smp_mb()        barrier()
 112 #define smp_rmb()       barrier()
 113 #define smp_wmb()       barrier()
 114 #define smp_mc()        barrier()
 115 #define smp_rmc()       barrier()
 116 #define smp_wmc()       barrier()
 117 #define smp_read_barrier_depends()
 118 #endif
 119
 120 #ifndef cpu_relax
 121 #define cpu_relax()      barrier()
 122 #endif
 123
 124 #ifdef __cplusplus
 125 }
 126 #endif
 127
 128 #endif /* _URCU_ARCH_GENERIC_H */