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   1 #ifndef __ARCH_S390_ATOMIC__
   2 #define __ARCH_S390_ATOMIC__
   3
   4 /*
   5  *  include/asm-s390/atomic.h
   6  *
   7  *  S390 version
   8  *    Copyright (C) 1999-2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
   9  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
  10  *               Denis Joseph Barrow,
  11  *               Arnd Bergmann (arndb@de.ibm.com)
  12  *
  13  *  Derived from "include/asm-i386/bitops.h"
  14  *    Copyright (C) 1992, Linus Torvalds
  15  *
  16  */
  17
  18 /*
  19  * Atomic operations that C can't guarantee us.  Useful for
  20  * resource counting etc..
  21  * S390 uses 'Compare And Swap' for atomicity in SMP enviroment
  22  */
  23
  24 typedef struct {
  25         volatile int counter;
  26 } __attribute__ ((aligned (4))) atomic_t;
  27 #define ATOMIC_INIT(i)  { (i) }
  28
  29 #ifdef __KERNEL__
  30
  31 #define __CS_LOOP(ptr, op_val, op_string) ({                            \
  32         typeof(ptr->counter) old_val, new_val;                          \
  33         __asm__ __volatile__("   l     %0,0(%3)\n"                      \
  34                              "0: lr    %1,%0\n"                         \
  35                              op_string "  %1,%4\n"                      \
  36                              "   cs    %0,%1,0(%3)\n"                   \
  37                              "   jl    0b"                              \
  38                              : "=&d" (old_val), "=&d" (new_val),        \
  39                                "=m" (((atomic_t *)(ptr))->counter)      \
  40                              : "a" (ptr), "d" (op_val),                 \
  41                                "m" (((atomic_t *)(ptr))->counter)       \
  42                              : "cc", "memory" );                        \
  43         new_val;                                                        \
  44 })
  45 #define atomic_read(v)          ((v)->counter)
  46 #define atomic_set(v,i)         (((v)->counter) = (i))
  47
  48 static __inline__ void atomic_add(int i, atomic_t * v)
  49 {
  50                __CS_LOOP(v, i, "ar");
  51 }
  52 static __inline__ int atomic_add_return(int i, atomic_t * v)
  53 {
  54         return __CS_LOOP(v, i, "ar");
  55 }
  56 static __inline__ int atomic_add_negative(int i, atomic_t * v)
  57 {
  58         return __CS_LOOP(v, i, "ar") < 0;
  59 }
  60 static __inline__ void atomic_sub(int i, atomic_t * v)
  61 {
  62                __CS_LOOP(v, i, "sr");
  63 }
  64 static __inline__ int atomic_sub_return(int i, atomic_t * v)
  65 {
  66         return __CS_LOOP(v, i, "sr");
  67 }
  68 static __inline__ void atomic_inc(volatile atomic_t * v)
  69 {
  70                __CS_LOOP(v, 1, "ar");
  71 }
  72 static __inline__ int atomic_inc_return(volatile atomic_t * v)
  73 {
  74         return __CS_LOOP(v, 1, "ar");
  75 }
  76
  77 static __inline__ int atomic_inc_and_test(volatile atomic_t * v)
  78 {
  79         return __CS_LOOP(v, 1, "ar") == 0;
  80 }
  81 static __inline__ void atomic_dec(volatile atomic_t * v)
  82 {
  83                __CS_LOOP(v, 1, "sr");
  84 }
  85 static __inline__ int atomic_dec_return(volatile atomic_t * v)
  86 {
  87         return __CS_LOOP(v, 1, "sr");
  88 }
  89 static __inline__ int atomic_dec_and_test(volatile atomic_t * v)
  90 {
  91         return __CS_LOOP(v, 1, "sr") == 0;
  92 }
  93 static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t * v)
  94 {
  95                __CS_LOOP(v, ~mask, "nr");
  96 }
  97 static __inline__ void atomic_set_mask(unsigned long mask, atomic_t * v)
  98 {
  99                __CS_LOOP(v, mask, "or");
 100 }
 101 #undef __CS_LOOP
 102
 103 #ifdef __s390x__
 104 typedef struct {
 105         volatile long long counter;
 106 } __attribute__ ((aligned (8))) atomic64_t;
 107 #define ATOMIC64_INIT(i)  { (i) }
 108
 109 #define __CSG_LOOP(ptr, op_val, op_string) ({                           \
 110         typeof(ptr->counter) old_val, new_val;                          \
 111         __asm__ __volatile__("   lg    %0,0(%3)\n"                      \
 112                              "0: lgr   %1,%0\n"                         \
 113                              op_string "  %1,%4\n"                      \
 114                              "   csg   %0,%1,0(%3)\n"                   \
 115                              "   jl    0b"                              \
 116                              : "=&d" (old_val), "=&d" (new_val),        \
 117                                "=m" (((atomic_t *)(ptr))->counter)      \
 118                              : "a" (ptr), "d" (op_val),                 \
 119                                "m" (((atomic_t *)(ptr))->counter)       \
 120                              : "cc", "memory" );                        \
 121         new_val;                                                        \
 122 })
 123 #define atomic64_read(v)          ((v)->counter)
 124 #define atomic64_set(v,i)         (((v)->counter) = (i))
 125
 126 static __inline__ void atomic64_add(long long i, atomic64_t * v)
 127 {
 128                __CSG_LOOP(v, i, "agr");
 129 }
 130 static __inline__ long long atomic64_add_return(long long i, atomic64_t * v)
 131 {
 132         return __CSG_LOOP(v, i, "agr");
 133 }
 134 static __inline__ long long atomic64_add_negative(long long i, atomic64_t * v)
 135 {
 136         return __CSG_LOOP(v, i, "agr") < 0;
 137 }
 138 static __inline__ void atomic64_sub(long long i, atomic64_t * v)
 139 {
 140                __CSG_LOOP(v, i, "sgr");
 141 }
 142 static __inline__ void atomic64_inc(volatile atomic64_t * v)
 143 {
 144                __CSG_LOOP(v, 1, "agr");
 145 }
 146 static __inline__ long long atomic64_inc_return(volatile atomic64_t * v)
 147 {
 148         return __CSG_LOOP(v, 1, "agr");
 149 }
 150 static __inline__ long long atomic64_inc_and_test(volatile atomic64_t * v)
 151 {
 152         return __CSG_LOOP(v, 1, "agr") == 0;
 153 }
 154 static __inline__ void atomic64_dec(volatile atomic64_t * v)
 155 {
 156                __CSG_LOOP(v, 1, "sgr");
 157 }
 158 static __inline__ long long atomic64_dec_return(volatile atomic64_t * v)
 159 {
 160         return __CSG_LOOP(v, 1, "sgr");
 161 }
 162 static __inline__ long long atomic64_dec_and_test(volatile atomic64_t * v)
 163 {
 164         return __CSG_LOOP(v, 1, "sgr") == 0;
 165 }
 166 static __inline__ void atomic64_clear_mask(unsigned long mask, atomic64_t * v)
 167 {
 168                __CSG_LOOP(v, ~mask, "ngr");
 169 }
 170 static __inline__ void atomic64_set_mask(unsigned long mask, atomic64_t * v)
 171 {
 172                __CSG_LOOP(v, mask, "ogr");
 173 }
 174
 175 #undef __CSG_LOOP
 176 #endif
 177
 178 /*
 179   returns 0  if expected_oldval==value in *v ( swap was successful )
 180   returns 1  if unsuccessful.
 181
 182   This is non-portable, use bitops or spinlocks instead!
 183 */
 184 static __inline__ int
 185 atomic_compare_and_swap(int expected_oldval,int new_val,atomic_t *v)
 186 {
 187         int retval;
 188
 189         __asm__ __volatile__(
 190                 "  lr   %0,%3\n"
 191                 "  cs   %0,%4,0(%2)\n"
 192                 "  ipm  %0\n"
 193                 "  srl  %0,28\n"
 194                 "0:"
 195                 : "=&d" (retval), "=m" (v->counter)
 196                 : "a" (v), "d" (expected_oldval) , "d" (new_val),
 197                   "m" (v->counter) : "cc", "memory" );
 198         return retval;
 199 }
 200
 201 #define atomic_cmpxchg(v, o, n) (atomic_compare_and_swap((o), (n), &((v)->counter)))
 202
 203 #define atomic_add_unless(v, a, u)                              \
 204 ({                                                              \
 205         int c, old;                                             \
 206         c = atomic_read(v);                                     \
 207         while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
 208                 c = old;                                        \
 209         c != (u);                                               \
 210 })
 211 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 212
 213 #define smp_mb__before_atomic_dec()     smp_mb()
 214 #define smp_mb__after_atomic_dec()      smp_mb()
 215 #define smp_mb__before_atomic_inc()     smp_mb()
 216 #define smp_mb__after_atomic_inc()      smp_mb()
 217
 218 #endif /* __KERNEL__ */
 219 #endif /* __ARCH_S390_ATOMIC__  */