arch/s390/include/asm/barrier.h

   1 /*
   2  * Copyright IBM Corp. 1999, 2009
   3  *
   4  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   5  */
   6
   7 #ifndef __ASM_BARRIER_H
   8 #define __ASM_BARRIER_H
   9
  10 /*
  11  * Force strict CPU ordering.
  12  * And yes, this is required on UP too when we're talking
  13  * to devices.
  14  */
  15
  16 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
  17 /* Fast-BCR without checkpoint synchronization */
  18 #define mb() do {  asm volatile("bcr 14,0" : : : "memory"); } while (0)
  19 #else
  20 #define mb() do {  asm volatile("bcr 15,0" : : : "memory"); } while (0)
  21 #endif
  22
  23 #define rmb()                           mb()
  24 #define wmb()                           mb()
  25 #define read_barrier_depends()          do { } while(0)
  26 #define smp_mb()                        mb()
  27 #define smp_rmb()                       rmb()
  28 #define smp_wmb()                       wmb()
  29 #define smp_read_barrier_depends()      read_barrier_depends()
  30 #define smp_mb__before_clear_bit()      smp_mb()
  31 #define smp_mb__after_clear_bit()       smp_mb()
  32
  33 #define set_mb(var, value)              do { var = value; mb(); } while (0)
  34
  35 #define smp_store_release(p, v)                                         \
  36 do {                                                                    \
  37         compiletime_assert_atomic_type(*p);                             \
  38         barrier();                                                      \
  39         ACCESS_ONCE(*p) = (v);                                          \
  40 } while (0)
  41
  42 #define smp_load_acquire(p)                                             \
  43 ({                                                                      \
  44         typeof(*p) ___p1 = ACCESS_ONCE(*p);                             \
  45         compiletime_assert_atomic_type(*p);                             \
  46         barrier();                                                      \
  47         ___p1;                                                          \
  48 })
  49
  50 #endif /* __ASM_BARRIER_H */