arch_atomic_s390.h

   1 #ifndef _ARCH_ATOMIC_S390_H
   2 #define _ARCH_ATOMIC_S390_H
   3
   4 /*
   5  * Atomic exchange operations for the S390 architecture. Based on information
   6  * taken from the Principles of Operation Appendix A "Conditional Swapping
   7  * Instructions (CS, CDS)".
   8  *
   9  * Copyright (c) 2009 Novell, Inc.
  10  * Author: Jan Blunck <jblunck@suse.de>
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a copy
  13  * of this software and associated documentation files (the "Software"), to
  14  * deal in the Software without restriction, including without limitation the
  15  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  16  * sell copies of the Software, and to permit persons to whom the Software is
  17  * furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included in
  20  * all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  28  * IN THE SOFTWARE.
  29  */
  30
  31 #ifndef __SIZEOF_LONG__
  32 #ifdef __s390x__
  33 #define __SIZEOF_LONG__ 8
  34 #else
  35 #define __SIZEOF_LONG__ 4
  36 #endif
  37 #endif
  38
  39 #ifndef BITS_PER_LONG
  40 #define BITS_PER_LONG   (__SIZEOF_LONG__ * 8)
  41 #endif
  42
  43 #ifndef _INCLUDE_API_H
  44
  45 static inline __attribute__((always_inline))
  46 unsigned int atomic_exchange_32(volatile unsigned int *addr, unsigned int val)
  47 {
  48         unsigned int result;
  49
  50         __asm__ __volatile__(
  51                 "0:     cs %0,%2,%1\n"
  52                 "       brc 4,0b\n"
  53                 : "=&r"(result), "=m" (*addr)
  54                 : "r"(val), "m" (*addr)
  55                 : "memory", "cc");
  56
  57         return result;
  58 }
  59
  60 #if (BITS_PER_LONG == 64)
  61
  62 static inline __attribute__((always_inline))
  63 unsigned long atomic_exchange_64(volatile unsigned long *addr,
  64                                  unsigned long val)
  65 {
  66         unsigned long result;
  67
  68         __asm__ __volatile__(
  69                 "0:     csg %0,%2,%1\n"
  70                 "       brc 4,0b\n"
  71                 : "=&r"(result), "=m" (*addr)
  72                 : "r"(val), "m" (*addr)
  73                 : "memory", "cc");
  74
  75         return result;
  76 }
  77
  78 #endif
  79
  80 static inline __attribute__((always_inline))
  81 unsigned long _atomic_exchange(volatile void *addr, unsigned long val, int len)
  82 {
  83         switch (len) {
  84         case 4:
  85                 return atomic_exchange_32(addr, val);
  86 #if (BITS_PER_LONG == 64)
  87         case 8:
  88                 return atomic_exchange_64(addr, val);
  89 #endif
  90         default:
  91                 __asm__ __volatile__(".long     0xd00d00");
  92         }
  93
  94         return 0;
  95 }
  96
  97 #define xchg(addr, v)                                                   \
  98         (__typeof__(*(addr))) _atomic_exchange((addr), (unsigned long)(v), \
  99                                                sizeof(*(addr)))
 100
 101 #endif /* #ifndef _INCLUDE_API_H */
 102
 103 #endif /* ARCH_ATOMIC_S390_H */