arch/alpha/include/asm/atomic.h

   1 #ifndef _ALPHA_ATOMIC_H
   2 #define _ALPHA_ATOMIC_H
   3
   4 #include <linux/types.h>
   5 #include <asm/barrier.h>
   6 #include <asm/cmpxchg.h>
   7
   8 /*
   9  * Atomic operations that C can't guarantee us.  Useful for
  10  * resource counting etc...
  11  *
  12  * But use these as seldom as possible since they are much slower
  13  * than regular operations.
  14  */
  15
  16
  17 #define ATOMIC_INIT(i)          { (i) }
  18 #define ATOMIC64_INIT(i)        { (i) }
  19
  20 #define atomic_read(v)          ACCESS_ONCE((v)->counter)
  21 #define atomic64_read(v)        ACCESS_ONCE((v)->counter)
  22
  23 #define atomic_set(v,i)         ((v)->counter = (i))
  24 #define atomic64_set(v,i)       ((v)->counter = (i))
  25
  26 /*
  27  * To get proper branch prediction for the main line, we must branch
  28  * forward to code at the end of this object's .text section, then
  29  * branch back to restart the operation.
  30  */
  31
  32 #define ATOMIC_OP(op)                                                   \
  33 static __inline__ void atomic_##op(int i, atomic_t * v)                 \
  34 {                                                                       \
  35         unsigned long temp;                                             \
  36         __asm__ __volatile__(                                           \
  37         "1:     ldl_l %0,%1\n"                                          \
  38         "       " #op "l %0,%2,%0\n"                                    \
  39         "       stl_c %0,%1\n"                                          \
  40         "       beq %0,2f\n"                                            \
  41         ".subsection 2\n"                                               \
  42         "2:     br 1b\n"                                                \
  43         ".previous"                                                     \
  44         :"=&r" (temp), "=m" (v->counter)                                \
  45         :"Ir" (i), "m" (v->counter));                                   \
  46 }                                                                       \
  47
  48 #define ATOMIC_OP_RETURN(op)                                            \
  49 static inline int atomic_##op##_return(int i, atomic_t *v)              \
  50 {                                                                       \
  51         long temp, result;                                              \
  52         smp_mb();                                                       \
  53         __asm__ __volatile__(                                           \
  54         "1:     ldl_l %0,%1\n"                                          \
  55         "       " #op "l %0,%3,%2\n"                                    \
  56         "       " #op "l %0,%3,%0\n"                                    \
  57         "       stl_c %0,%1\n"                                          \
  58         "       beq %0,2f\n"                                            \
  59         ".subsection 2\n"                                               \
  60         "2:     br 1b\n"                                                \
  61         ".previous"                                                     \
  62         :"=&r" (temp), "=m" (v->counter), "=&r" (result)                \
  63         :"Ir" (i), "m" (v->counter) : "memory");                        \
  64         smp_mb();                                                       \
  65         return result;                                                  \
  66 }
  67
  68 #define ATOMIC64_OP(op)                                                 \
  69 static __inline__ void atomic64_##op(long i, atomic64_t * v)            \
  70 {                                                                       \
  71         unsigned long temp;                                             \
  72         __asm__ __volatile__(                                           \
  73         "1:     ldq_l %0,%1\n"                                          \
  74         "       " #op "q %0,%2,%0\n"                                    \
  75         "       stq_c %0,%1\n"                                          \
  76         "       beq %0,2f\n"                                            \
  77         ".subsection 2\n"                                               \
  78         "2:     br 1b\n"                                                \
  79         ".previous"                                                     \
  80         :"=&r" (temp), "=m" (v->counter)                                \
  81         :"Ir" (i), "m" (v->counter));                                   \
  82 }                                                                       \
  83
  84 #define ATOMIC64_OP_RETURN(op)                                          \
  85 static __inline__ long atomic64_##op##_return(long i, atomic64_t * v)   \
  86 {                                                                       \
  87         long temp, result;                                              \
  88         smp_mb();                                                       \
  89         __asm__ __volatile__(                                           \
  90         "1:     ldq_l %0,%1\n"                                          \
  91         "       " #op "q %0,%3,%2\n"                                    \
  92         "       " #op "q %0,%3,%0\n"                                    \
  93         "       stq_c %0,%1\n"                                          \
  94         "       beq %0,2f\n"                                            \
  95         ".subsection 2\n"                                               \
  96         "2:     br 1b\n"                                                \
  97         ".previous"                                                     \
  98         :"=&r" (temp), "=m" (v->counter), "=&r" (result)                \
  99         :"Ir" (i), "m" (v->counter) : "memory");                        \
 100         smp_mb();                                                       \
 101         return result;                                                  \
 102 }
 103
 104 #define ATOMIC_OPS(opg)                                                 \
 105         ATOMIC_OP(opg)                                                  \
 106         ATOMIC_OP_RETURN(opg)                                           \
 107         ATOMIC64_OP(opg)                                                \
 108         ATOMIC64_OP_RETURN(opg)
 109
 110 ATOMIC_OPS(add)
 111 ATOMIC_OPS(sub)
 112
 113 #undef ATOMIC_OPS
 114 #undef ATOMIC64_OP_RETURN
 115 #undef ATOMIC64_OP
 116 #undef ATOMIC_OP_RETURN
 117 #undef ATOMIC_OP
 118
 119 #define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 120 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 121
 122 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 123 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 124
 125 /**
 126  * __atomic_add_unless - add unless the number is a given value
 127  * @v: pointer of type atomic_t
 128  * @a: the amount to add to v...
 129  * @u: ...unless v is equal to u.
 130  *
 131  * Atomically adds @a to @v, so long as it was not @u.
 132  * Returns the old value of @v.
 133  */
 134 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
 135 {
 136         int c, new, old;
 137         smp_mb();
 138         __asm__ __volatile__(
 139         "1:     ldl_l   %[old],%[mem]\n"
 140         "       cmpeq   %[old],%[u],%[c]\n"
 141         "       addl    %[old],%[a],%[new]\n"
 142         "       bne     %[c],2f\n"
 143         "       stl_c   %[new],%[mem]\n"
 144         "       beq     %[new],3f\n"
 145         "2:\n"
 146         ".subsection 2\n"
 147         "3:     br      1b\n"
 148         ".previous"
 149         : [old] "=&r"(old), [new] "=&r"(new), [c] "=&r"(c)
 150         : [mem] "m"(*v), [a] "rI"(a), [u] "rI"((long)u)
 151         : "memory");
 152         smp_mb();
 153         return old;
 154 }
 155
 156
 157 /**
 158  * atomic64_add_unless - add unless the number is a given value
 159  * @v: pointer of type atomic64_t
 160  * @a: the amount to add to v...
 161  * @u: ...unless v is equal to u.
 162  *
 163  * Atomically adds @a to @v, so long as it was not @u.
 164  * Returns true iff @v was not @u.
 165  */
 166 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 167 {
 168         long c, tmp;
 169         smp_mb();
 170         __asm__ __volatile__(
 171         "1:     ldq_l   %[tmp],%[mem]\n"
 172         "       cmpeq   %[tmp],%[u],%[c]\n"
 173         "       addq    %[tmp],%[a],%[tmp]\n"
 174         "       bne     %[c],2f\n"
 175         "       stq_c   %[tmp],%[mem]\n"
 176         "       beq     %[tmp],3f\n"
 177         "2:\n"
 178         ".subsection 2\n"
 179         "3:     br      1b\n"
 180         ".previous"
 181         : [tmp] "=&r"(tmp), [c] "=&r"(c)
 182         : [mem] "m"(*v), [a] "rI"(a), [u] "rI"(u)
 183         : "memory");
 184         smp_mb();
 185         return !c;
 186 }
 187
 188 /*
 189  * atomic64_dec_if_positive - decrement by 1 if old value positive
 190  * @v: pointer of type atomic_t
 191  *
 192  * The function returns the old value of *v minus 1, even if
 193  * the atomic variable, v, was not decremented.
 194  */
 195 static inline long atomic64_dec_if_positive(atomic64_t *v)
 196 {
 197         long old, tmp;
 198         smp_mb();
 199         __asm__ __volatile__(
 200         "1:     ldq_l   %[old],%[mem]\n"
 201         "       subq    %[old],1,%[tmp]\n"
 202         "       ble     %[old],2f\n"
 203         "       stq_c   %[tmp],%[mem]\n"
 204         "       beq     %[tmp],3f\n"
 205         "2:\n"
 206         ".subsection 2\n"
 207         "3:     br      1b\n"
 208         ".previous"
 209         : [old] "=&r"(old), [tmp] "=&r"(tmp)
 210         : [mem] "m"(*v)
 211         : "memory");
 212         smp_mb();
 213         return old - 1;
 214 }
 215
 216 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 217
 218 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
 219 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
 220
 221 #define atomic_dec_return(v) atomic_sub_return(1,(v))
 222 #define atomic64_dec_return(v) atomic64_sub_return(1,(v))
 223
 224 #define atomic_inc_return(v) atomic_add_return(1,(v))
 225 #define atomic64_inc_return(v) atomic64_add_return(1,(v))
 226
 227 #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
 228 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)
 229
 230 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
 231 #define atomic64_inc_and_test(v) (atomic64_add_return(1, (v)) == 0)
 232
 233 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
 234 #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
 235
 236 #define atomic_inc(v) atomic_add(1,(v))
 237 #define atomic64_inc(v) atomic64_add(1,(v))
 238
 239 #define atomic_dec(v) atomic_sub(1,(v))
 240 #define atomic64_dec(v) atomic64_sub(1,(v))
 241
 242 #endif /* _ALPHA_ATOMIC_H */