include/asm-alpha/atomic.h

   1 #ifndef _ALPHA_ATOMIC_H
   2 #define _ALPHA_ATOMIC_H
   3
   4 #include <asm/barrier.h>
   5
   6 /*
   7  * Atomic operations that C can't guarantee us.  Useful for
   8  * resource counting etc...
   9  *
  10  * But use these as seldom as possible since they are much slower
  11  * than regular operations.
  12  */
  13
  14
  15 /*
  16  * Counter is volatile to make sure gcc doesn't try to be clever
  17  * and move things around on us. We need to use _exactly_ the address
  18  * the user gave us, not some alias that contains the same information.
  19  */
  20 typedef struct { volatile int counter; } atomic_t;
  21 typedef struct { volatile long counter; } atomic64_t;
  22
  23 #define ATOMIC_INIT(i)          ( (atomic_t) { (i) } )
  24 #define ATOMIC64_INIT(i)        ( (atomic64_t) { (i) } )
  25
  26 #define atomic_read(v)          ((v)->counter + 0)
  27 #define atomic64_read(v)        ((v)->counter + 0)
  28
  29 #define atomic_set(v,i)         ((v)->counter = (i))
  30 #define atomic64_set(v,i)       ((v)->counter = (i))
  31
  32 /*
  33  * To get proper branch prediction for the main line, we must branch
  34  * forward to code at the end of this object's .text section, then
  35  * branch back to restart the operation.
  36  */
  37
  38 static __inline__ void atomic_add(int i, atomic_t * v)
  39 {
  40         unsigned long temp;
  41         __asm__ __volatile__(
  42         "1:     ldl_l %0,%1\n"
  43         "       addl %0,%2,%0\n"
  44         "       stl_c %0,%1\n"
  45         "       beq %0,2f\n"
  46         ".subsection 2\n"
  47         "2:     br 1b\n"
  48         ".previous"
  49         :"=&r" (temp), "=m" (v->counter)
  50         :"Ir" (i), "m" (v->counter));
  51 }
  52
  53 static __inline__ void atomic64_add(long i, atomic64_t * v)
  54 {
  55         unsigned long temp;
  56         __asm__ __volatile__(
  57         "1:     ldq_l %0,%1\n"
  58         "       addq %0,%2,%0\n"
  59         "       stq_c %0,%1\n"
  60         "       beq %0,2f\n"
  61         ".subsection 2\n"
  62         "2:     br 1b\n"
  63         ".previous"
  64         :"=&r" (temp), "=m" (v->counter)
  65         :"Ir" (i), "m" (v->counter));
  66 }
  67
  68 static __inline__ void atomic_sub(int i, atomic_t * v)
  69 {
  70         unsigned long temp;
  71         __asm__ __volatile__(
  72         "1:     ldl_l %0,%1\n"
  73         "       subl %0,%2,%0\n"
  74         "       stl_c %0,%1\n"
  75         "       beq %0,2f\n"
  76         ".subsection 2\n"
  77         "2:     br 1b\n"
  78         ".previous"
  79         :"=&r" (temp), "=m" (v->counter)
  80         :"Ir" (i), "m" (v->counter));
  81 }
  82
  83 static __inline__ void atomic64_sub(long i, atomic64_t * v)
  84 {
  85         unsigned long temp;
  86         __asm__ __volatile__(
  87         "1:     ldq_l %0,%1\n"
  88         "       subq %0,%2,%0\n"
  89         "       stq_c %0,%1\n"
  90         "       beq %0,2f\n"
  91         ".subsection 2\n"
  92         "2:     br 1b\n"
  93         ".previous"
  94         :"=&r" (temp), "=m" (v->counter)
  95         :"Ir" (i), "m" (v->counter));
  96 }
  97
  98
  99 /*
 100  * Same as above, but return the result value
 101  */
 102 static __inline__ long atomic_add_return(int i, atomic_t * v)
 103 {
 104         long temp, result;
 105         smp_mb();
 106         __asm__ __volatile__(
 107         "1:     ldl_l %0,%1\n"
 108         "       addl %0,%3,%2\n"
 109         "       addl %0,%3,%0\n"
 110         "       stl_c %0,%1\n"
 111         "       beq %0,2f\n"
 112         ".subsection 2\n"
 113         "2:     br 1b\n"
 114         ".previous"
 115         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 116         :"Ir" (i), "m" (v->counter) : "memory");
 117         smp_mb();
 118         return result;
 119 }
 120
 121 static __inline__ long atomic64_add_return(long i, atomic64_t * v)
 122 {
 123         long temp, result;
 124         smp_mb();
 125         __asm__ __volatile__(
 126         "1:     ldq_l %0,%1\n"
 127         "       addq %0,%3,%2\n"
 128         "       addq %0,%3,%0\n"
 129         "       stq_c %0,%1\n"
 130         "       beq %0,2f\n"
 131         ".subsection 2\n"
 132         "2:     br 1b\n"
 133         ".previous"
 134         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 135         :"Ir" (i), "m" (v->counter) : "memory");
 136         smp_mb();
 137         return result;
 138 }
 139
 140 static __inline__ long atomic_sub_return(int i, atomic_t * v)
 141 {
 142         long temp, result;
 143         smp_mb();
 144         __asm__ __volatile__(
 145         "1:     ldl_l %0,%1\n"
 146         "       subl %0,%3,%2\n"
 147         "       subl %0,%3,%0\n"
 148         "       stl_c %0,%1\n"
 149         "       beq %0,2f\n"
 150         ".subsection 2\n"
 151         "2:     br 1b\n"
 152         ".previous"
 153         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 154         :"Ir" (i), "m" (v->counter) : "memory");
 155         smp_mb();
 156         return result;
 157 }
 158
 159 static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
 160 {
 161         long temp, result;
 162         smp_mb();
 163         __asm__ __volatile__(
 164         "1:     ldq_l %0,%1\n"
 165         "       subq %0,%3,%2\n"
 166         "       subq %0,%3,%0\n"
 167         "       stq_c %0,%1\n"
 168         "       beq %0,2f\n"
 169         ".subsection 2\n"
 170         "2:     br 1b\n"
 171         ".previous"
 172         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 173         :"Ir" (i), "m" (v->counter) : "memory");
 174         smp_mb();
 175         return result;
 176 }
 177
 178 #define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 179 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 180
 181 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 182 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 183
 184 /**
 185  * atomic_add_unless - add unless the number is a given value
 186  * @v: pointer of type atomic_t
 187  * @a: the amount to add to v...
 188  * @u: ...unless v is equal to u.
 189  *
 190  * Atomically adds @a to @v, so long as it was not @u.
 191  * Returns non-zero if @v was not @u, and zero otherwise.
 192  */
 193 #define atomic_add_unless(v, a, u)                              \
 194 ({                                                              \
 195         __typeof__((v)->counter) c, old;                        \
 196         c = atomic_read(v);                                     \
 197         for (;;) {                                              \
 198                 if (unlikely(c == (u)))                         \
 199                         break;                                  \
 200                 old = atomic_cmpxchg((v), c, c + (a));          \
 201                 if (likely(old == c))                           \
 202                         break;                                  \
 203                 c = old;                                        \
 204         }                                                       \
 205         c != (u);                                               \
 206 })
 207 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 208
 209 /**
 210  * atomic64_add_unless - add unless the number is a given value
 211  * @v: pointer of type atomic64_t
 212  * @a: the amount to add to v...
 213  * @u: ...unless v is equal to u.
 214  *
 215  * Atomically adds @a to @v, so long as it was not @u.
 216  * Returns non-zero if @v was not @u, and zero otherwise.
 217  */
 218 #define atomic64_add_unless(v, a, u)                            \
 219 ({                                                              \
 220         __typeof__((v)->counter) c, old;                        \
 221         c = atomic64_read(v);                                   \
 222         for (;;) {                                              \
 223                 if (unlikely(c == (u)))                         \
 224                         break;                                  \
 225                 old = atomic64_cmpxchg((v), c, c + (a));        \
 226                 if (likely(old == c))                           \
 227                         break;                                  \
 228                 c = old;                                        \
 229         }                                                       \
 230         c != (u);                                               \
 231 })
 232 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 233
 234 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
 235 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
 236
 237 #define atomic_dec_return(v) atomic_sub_return(1,(v))
 238 #define atomic64_dec_return(v) atomic64_sub_return(1,(v))
 239
 240 #define atomic_inc_return(v) atomic_add_return(1,(v))
 241 #define atomic64_inc_return(v) atomic64_add_return(1,(v))
 242
 243 #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
 244 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)
 245
 246 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
 247 #define atomic64_inc_and_test(v) (atomic64_add_return(1, (v)) == 0)
 248
 249 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
 250 #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
 251
 252 #define atomic_inc(v) atomic_add(1,(v))
 253 #define atomic64_inc(v) atomic64_add(1,(v))
 254
 255 #define atomic_dec(v) atomic_sub(1,(v))
 256 #define atomic64_dec(v) atomic64_sub(1,(v))
 257
 258 #define smp_mb__before_atomic_dec()     smp_mb()
 259 #define smp_mb__after_atomic_dec()      smp_mb()
 260 #define smp_mb__before_atomic_inc()     smp_mb()
 261 #define smp_mb__after_atomic_inc()      smp_mb()
 262
 263 #include <asm-generic/atomic.h>
 264 #endif /* _ALPHA_ATOMIC_H */