LXR linux/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)                                                   \
  33static __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)                                            \
  49static 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)                                                 \
  69static __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)                                          \
  85static __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
 110ATOMIC_OPS(add)
 111ATOMIC_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 */
 134static __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 */
 166static __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 */
 195static 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 */
 243