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   1 #ifndef __ARCH_S390_ATOMIC__
   2 #define __ARCH_S390_ATOMIC__
   3
   4 #include <linux/compiler.h>
   5
   6 /*
   7  *  include/asm-s390/atomic.h
   8  *
   9  *  S390 version
  10  *    Copyright (C) 1999-2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
  11  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
  12  *               Denis Joseph Barrow,
  13  *               Arnd Bergmann (arndb@de.ibm.com)
  14  *
  15  *  Derived from "include/asm-i386/bitops.h"
  16  *    Copyright (C) 1992, Linus Torvalds
  17  *
  18  */
  19
  20 /*
  21  * Atomic operations that C can't guarantee us.  Useful for
  22  * resource counting etc..
  23  * S390 uses 'Compare And Swap' for atomicity in SMP enviroment
  24  */
  25
  26 typedef struct {
  27         volatile int counter;
  28 } __attribute__ ((aligned (4))) atomic_t;
  29 #define ATOMIC_INIT(i)  { (i) }
  30
  31 #ifdef __KERNEL__
  32
  33 #define __CS_LOOP(ptr, op_val, op_string) ({                            \
  34         typeof(ptr->counter) old_val, new_val;                          \
  35         __asm__ __volatile__("   l     %0,0(%3)\n"                      \
  36                              "0: lr    %1,%0\n"                         \
  37                              op_string "  %1,%4\n"                      \
  38                              "   cs    %0,%1,0(%3)\n"                   \
  39                              "   jl    0b"                              \
  40                              : "=&d" (old_val), "=&d" (new_val),        \
  41                                "=m" (((atomic_t *)(ptr))->counter)      \
  42                              : "a" (ptr), "d" (op_val),                 \
  43                                "m" (((atomic_t *)(ptr))->counter)       \
  44                              : "cc", "memory" );                        \
  45         new_val;                                                        \
  46 })
  47 #define atomic_read(v)          ((v)->counter)
  48 #define atomic_set(v,i)         (((v)->counter) = (i))
  49
  50 static __inline__ int atomic_add_return(int i, atomic_t * v)
  51 {
  52         return __CS_LOOP(v, i, "ar");
  53 }
  54 #define atomic_add(_i, _v)              atomic_add_return(_i, _v)
  55 #define atomic_add_negative(_i, _v)     (atomic_add_return(_i, _v) < 0)
  56 #define atomic_inc(_v)                  atomic_add_return(1, _v)
  57 #define atomic_inc_return(_v)           atomic_add_return(1, _v)
  58 #define atomic_inc_and_test(_v)         (atomic_add_return(1, _v) == 0)
  59
  60 static __inline__ int atomic_sub_return(int i, atomic_t * v)
  61 {
  62         return __CS_LOOP(v, i, "sr");
  63 }
  64 #define atomic_sub(_i, _v)              atomic_sub_return(_i, _v)
  65 #define atomic_sub_and_test(_i, _v)     (atomic_sub_return(_i, _v) == 0)
  66 #define atomic_dec(_v)                  atomic_sub_return(1, _v)
  67 #define atomic_dec_return(_v)           atomic_sub_return(1, _v)
  68 #define atomic_dec_and_test(_v)         (atomic_sub_return(1, _v) == 0)
  69
  70 static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t * v)
  71 {
  72                __CS_LOOP(v, ~mask, "nr");
  73 }
  74
  75 static __inline__ void atomic_set_mask(unsigned long mask, atomic_t * v)
  76 {
  77                __CS_LOOP(v, mask, "or");
  78 }
  79
  80 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
  81
  82 static __inline__ int atomic_cmpxchg(atomic_t *v, int old, int new)
  83 {
  84         __asm__ __volatile__("  cs   %0,%3,0(%2)\n"
  85                              : "+d" (old), "=m" (v->counter)
  86                              : "a" (v), "d" (new), "m" (v->counter)
  87                              : "cc", "memory" );
  88         return old;
  89 }
  90
  91 static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
  92 {
  93         int c, old;
  94         c = atomic_read(v);
  95         for (;;) {
  96                 if (unlikely(c == u))
  97                         break;
  98                 old = atomic_cmpxchg(v, c, c + a);
  99                 if (likely(old == c))
 100                         break;
 101                 c = old;
 102         }
 103         return c != u;
 104 }
 105
 106 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 107
 108 #undef __CS_LOOP
 109
 110 #ifdef __s390x__
 111 typedef struct {
 112         volatile long long counter;
 113 } __attribute__ ((aligned (8))) atomic64_t;
 114 #define ATOMIC64_INIT(i)  { (i) }
 115
 116 #define __CSG_LOOP(ptr, op_val, op_string) ({                           \
 117         typeof(ptr->counter) old_val, new_val;                          \
 118         __asm__ __volatile__("   lg    %0,0(%3)\n"                      \
 119                              "0: lgr   %1,%0\n"                         \
 120                              op_string "  %1,%4\n"                      \
 121                              "   csg   %0,%1,0(%3)\n"                   \
 122                              "   jl    0b"                              \
 123                              : "=&d" (old_val), "=&d" (new_val),        \
 124                                "=m" (((atomic_t *)(ptr))->counter)      \
 125                              : "a" (ptr), "d" (op_val),                 \
 126                                "m" (((atomic_t *)(ptr))->counter)       \
 127                              : "cc", "memory" );                        \
 128         new_val;                                                        \
 129 })
 130 #define atomic64_read(v)          ((v)->counter)
 131 #define atomic64_set(v,i)         (((v)->counter) = (i))
 132
 133 static __inline__ long long atomic64_add_return(long long i, atomic64_t * v)
 134 {
 135         return __CSG_LOOP(v, i, "agr");
 136 }
 137 #define atomic64_add(_i, _v)            atomic64_add_return(_i, _v)
 138 #define atomic64_add_negative(_i, _v)   (atomic64_add_return(_i, _v) < 0)
 139 #define atomic64_inc(_v)                atomic64_add_return(1, _v)
 140 #define atomic64_inc_return(_v)         atomic64_add_return(1, _v)
 141 #define atomic64_inc_and_test(_v)       (atomic64_add_return(1, _v) == 0)
 142
 143 static __inline__ long long atomic64_sub_return(long long i, atomic64_t * v)
 144 {
 145         return __CSG_LOOP(v, i, "sgr");
 146 }
 147 #define atomic64_sub(_i, _v)            atomic64_sub_return(_i, _v)
 148 #define atomic64_sub_and_test(_i, _v)   (atomic64_sub_return(_i, _v) == 0)
 149 #define atomic64_dec(_v)                atomic64_sub_return(1, _v)
 150 #define atomic64_dec_return(_v)         atomic64_sub_return(1, _v)
 151 #define atomic64_dec_and_test(_v)       (atomic64_sub_return(1, _v) == 0)
 152
 153 static __inline__ void atomic64_clear_mask(unsigned long mask, atomic64_t * v)
 154 {
 155                __CSG_LOOP(v, ~mask, "ngr");
 156 }
 157
 158 static __inline__ void atomic64_set_mask(unsigned long mask, atomic64_t * v)
 159 {
 160                __CSG_LOOP(v, mask, "ogr");
 161 }
 162
 163 static __inline__ long long atomic64_cmpxchg(atomic64_t *v,
 164                                              long long old, long long new)
 165 {
 166         __asm__ __volatile__("  csg  %0,%3,0(%2)\n"
 167                              : "+d" (old), "=m" (v->counter)
 168                              : "a" (v), "d" (new), "m" (v->counter)
 169                              : "cc", "memory" );
 170         return old;
 171 }
 172
 173 static __inline__ int atomic64_add_unless(atomic64_t *v,
 174                                           long long a, long long u)
 175 {
 176         long long c, old;
 177         c = atomic64_read(v);
 178         for (;;) {
 179                 if (unlikely(c == u))
 180                         break;
 181                 old = atomic64_cmpxchg(v, c, c + a);
 182                 if (likely(old == c))
 183                         break;
 184                 c = old;
 185         }
 186         return c != u;
 187 }
 188
 189 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 190
 191 #undef __CSG_LOOP
 192 #endif
 193
 194 #define smp_mb__before_atomic_dec()     smp_mb()
 195 #define smp_mb__after_atomic_dec()      smp_mb()
 196 #define smp_mb__before_atomic_inc()     smp_mb()
 197 #define smp_mb__after_atomic_inc()      smp_mb()
 198
 199 #include <asm-generic/atomic.h>
 200 #endif /* __KERNEL__ */
 201 #endif /* __ARCH_S390_ATOMIC__  */