include/urcu/uatomic/s390.h

   1 #ifndef _URCU_UATOMIC_ARCH_S390_H
   2 #define _URCU_UATOMIC_ARCH_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  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  12  *
  13  * Permission is hereby granted, free of charge, to any person obtaining a copy
  14  * of this software and associated documentation files (the "Software"), to
  15  * deal in the Software without restriction, including without limitation the
  16  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  17  * sell copies of the Software, and to permit persons to whom the Software is
  18  * furnished to do so, subject to the following conditions:
  19  *
  20  * The above copyright notice and this permission notice shall be included in
  21  * all copies or substantial portions of the Software.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  26  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  28  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  29  * IN THE SOFTWARE.
  30  */
  31
  32 #include <urcu/compiler.h>
  33 #include <urcu/system.h>
  34
  35 #ifdef __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
  40 #define COMPILER_HAVE_SHORT_MEM_OPERAND
  41 #endif
  42
  43 /*
  44  * MEMOP assembler operand rules:
  45  * - op refer to MEMOP_IN operand
  46  * - MEMOP_IN can expand to more than a single operand. Use it at the end of
  47  *   operand list only.
  48  */
  49
  50 #ifdef COMPILER_HAVE_SHORT_MEM_OPERAND
  51
  52 #define MEMOP_OUT(addr) "=Q" (*(addr))
  53 #define MEMOP_IN(addr)  "Q" (*(addr))
  54 #define MEMOP_REF(op)   #op             /* op refer to MEMOP_IN operand */
  55
  56 #else /* !COMPILER_HAVE_SHORT_MEM_OPERAND */
  57
  58 #define MEMOP_OUT(addr) "=m" (*(addr))
  59 #define MEMOP_IN(addr)  "a" (addr), "m" (*(addr))
  60 #define MEMOP_REF(op)   "0(" #op ")"    /* op refer to MEMOP_IN operand */
  61
  62 #endif /* !COMPILER_HAVE_SHORT_MEM_OPERAND */
  63
  64 /*
  65  * The __hp() macro casts the void pointer @x to a pointer to a structure
  66  * containing an array of char of the specified size. This allows passing the
  67  * @addr arguments of the following inline functions as "m" and "+m" operands
  68  * to the assembly. The @size parameter should be a constant to support
  69  * compilers such as clang which do not support VLA. Create typedefs because
  70  * C++ does not allow types be defined in casts.
  71  */
  72
  73 typedef struct { char v[4]; } __hp_4;
  74 typedef struct { char v[8]; } __hp_8;
  75
  76 #define __hp(size, x)   ((__hp_##size *)(x))
  77
  78 /* xchg */
  79
  80 static inline __attribute__((always_inline))
  81 unsigned long _uatomic_exchange(volatile void *addr, unsigned long val, int len)
  82 {
  83         switch (len) {
  84         case 4:
  85         {
  86                 unsigned int old_val;
  87
  88                 __asm__ __volatile__(
  89                         "0:     cs %0,%2," MEMOP_REF(%3) "\n"
  90                         "       brc 4,0b\n"
  91                         : "=&r" (old_val), MEMOP_OUT (__hp(4, addr))
  92                         : "r" (val), MEMOP_IN (__hp(4, addr))
  93                         : "memory", "cc");
  94                 return old_val;
  95         }
  96 #if (CAA_BITS_PER_LONG == 64)
  97         case 8:
  98         {
  99                 unsigned long old_val;
 100
 101                 __asm__ __volatile__(
 102                         "0:     csg %0,%2," MEMOP_REF(%3) "\n"
 103                         "       brc 4,0b\n"
 104                         : "=&r" (old_val), MEMOP_OUT (__hp(8, addr))
 105                         : "r" (val), MEMOP_IN (__hp(8, addr))
 106                         : "memory", "cc");
 107                 return old_val;
 108         }
 109 #endif
 110         default:
 111                 __asm__ __volatile__(".long     0xd00d00");
 112         }
 113
 114         return 0;
 115 }
 116
 117 #define uatomic_xchg(addr, v)                                               \
 118         (__typeof__(*(addr))) _uatomic_exchange((addr),                     \
 119                                                 caa_cast_long_keep_sign(v), \
 120                                                 sizeof(*(addr)))
 121
 122 /* cmpxchg */
 123
 124 static inline __attribute__((always_inline))
 125 unsigned long _uatomic_cmpxchg(void *addr, unsigned long old,
 126                                unsigned long _new, int len)
 127 {
 128         switch (len) {
 129         case 4:
 130         {
 131                 unsigned int old_val = (unsigned int)old;
 132
 133                 __asm__ __volatile__(
 134                         "       cs %0,%2," MEMOP_REF(%3) "\n"
 135                         : "+r" (old_val), MEMOP_OUT (__hp(4, addr))
 136                         : "r" (_new), MEMOP_IN (__hp(4, addr))
 137                         : "memory", "cc");
 138                 return old_val;
 139         }
 140 #if (CAA_BITS_PER_LONG == 64)
 141         case 8:
 142         {
 143                 __asm__ __volatile__(
 144                         "       csg %0,%2," MEMOP_REF(%3) "\n"
 145                         : "+r" (old), MEMOP_OUT (__hp(8, addr))
 146                         : "r" (_new), MEMOP_IN (__hp(8, addr))
 147                         : "memory", "cc");
 148                 return old;
 149         }
 150 #endif
 151         default:
 152                 __asm__ __volatile__(".long     0xd00d00");
 153         }
 154
 155         return 0;
 156 }
 157
 158 #define uatomic_cmpxchg(addr, old, _new)                                     \
 159         (__typeof__(*(addr))) _uatomic_cmpxchg((addr),                       \
 160                                                caa_cast_long_keep_sign(old), \
 161                                                caa_cast_long_keep_sign(_new),\
 162                                                sizeof(*(addr)))
 163
 164 #ifdef __cplusplus
 165 }
 166 #endif
 167
 168 #include <urcu/uatomic/generic.h>
 169
 170 #endif /* _URCU_UATOMIC_ARCH_S390_H */