include/asm-alpha/atomic.h

   1 #ifndef _ALPHA_ATOMIC_H
   2 #define _ALPHA_ATOMIC_H
   3
   4 #include <asm/barrier.h>
   5 #include <asm/system.h>
   6
   7 /*
   8  * Atomic operations that C can't guarantee us.  Useful for
   9  * resource counting etc...
  10  *
  11  * But use these as seldom as possible since they are much slower
  12  * than regular operations.
  13  */
  14
  15
  16 /*
  17  * Counter is volatile to make sure gcc doesn't try to be clever
  18  * and move things around on us. We need to use _exactly_ the address
  19  * the user gave us, not some alias that contains the same information.
  20  */
  21 typedef struct { volatile int counter; } atomic_t;
  22 typedef struct { volatile long counter; } atomic64_t;
  23
  24 #define ATOMIC_INIT(i)          ( (atomic_t) { (i) } )
  25 #define ATOMIC64_INIT(i)        ( (atomic64_t) { (i) } )
  26
  27 #define atomic_read(v)          ((v)->counter + 0)
  28 #define atomic64_read(v)        ((v)->counter + 0)
  29
  30 #define atomic_set(v,i)         ((v)->counter = (i))
  31 #define atomic64_set(v,i)       ((v)->counter = (i))
  32
  33 /*
  34  * To get proper branch prediction for the main line, we must branch
  35  * forward to code at the end of this object's .text section, then
  36  * branch back to restart the operation.
  37  */
  38
  39 static __inline__ void atomic_add(int i, atomic_t * v)
  40 {
  41         unsigned long temp;
  42         __asm__ __volatile__(
  43         "1:     ldl_l %0,%1\n"
  44         "       addl %0,%2,%0\n"
  45         "       stl_c %0,%1\n"
  46         "       beq %0,2f\n"
  47         ".subsection 2\n"
  48         "2:     br 1b\n"
  49         ".previous"
  50         :"=&r" (temp), "=m" (v->counter)
  51         :"Ir" (i), "m" (v->counter));
  52 }
  53
  54 static __inline__ void atomic64_add(long i, atomic64_t * v)
  55 {
  56         unsigned long temp;
  57         __asm__ __volatile__(
  58         "1:     ldq_l %0,%1\n"
  59         "       addq %0,%2,%0\n"
  60         "       stq_c %0,%1\n"
  61         "       beq %0,2f\n"
  62         ".subsection 2\n"
  63         "2:     br 1b\n"
  64         ".previous"
  65         :"=&r" (temp), "=m" (v->counter)
  66         :"Ir" (i), "m" (v->counter));
  67 }
  68
  69 static __inline__ void atomic_sub(int i, atomic_t * v)
  70 {
  71         unsigned long temp;
  72         __asm__ __volatile__(
  73         "1:     ldl_l %0,%1\n"
  74         "       subl %0,%2,%0\n"
  75         "       stl_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 static __inline__ void atomic64_sub(long i, atomic64_t * v)
  85 {
  86         unsigned long temp;
  87         __asm__ __volatile__(
  88         "1:     ldq_l %0,%1\n"
  89         "       subq %0,%2,%0\n"
  90         "       stq_c %0,%1\n"
  91         "       beq %0,2f\n"
  92         ".subsection 2\n"
  93         "2:     br 1b\n"
  94         ".previous"
  95         :"=&r" (temp), "=m" (v->counter)
  96         :"Ir" (i), "m" (v->counter));
  97 }
  98
  99
 100 /*
 101  * Same as above, but return the result value
 102  */
 103 static __inline__ long atomic_add_return(int i, atomic_t * v)
 104 {
 105         long temp, result;
 106         smp_mb();
 107         __asm__ __volatile__(
 108         "1:     ldl_l %0,%1\n"
 109         "       addl %0,%3,%2\n"
 110         "       addl %0,%3,%0\n"
 111         "       stl_c %0,%1\n"
 112         "       beq %0,2f\n"
 113         ".subsection 2\n"
 114         "2:     br 1b\n"
 115         ".previous"
 116         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 117         :"Ir" (i), "m" (v->counter) : "memory");
 118         smp_mb();
 119         return result;
 120 }
 121
 122 static __inline__ long atomic64_add_return(long i, atomic64_t * v)
 123 {
 124         long temp, result;
 125         smp_mb();
 126         __asm__ __volatile__(
 127         "1:     ldq_l %0,%1\n"
 128         "       addq %0,%3,%2\n"
 129         "       addq %0,%3,%0\n"
 130         "       stq_c %0,%1\n"
 131         "       beq %0,2f\n"
 132         ".subsection 2\n"
 133         "2:     br 1b\n"
 134         ".previous"
 135         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 136         :"Ir" (i), "m" (v->counter) : "memory");
 137         smp_mb();
 138         return result;
 139 }
 140
 141 static __inline__ long atomic_sub_return(int i, atomic_t * v)
 142 {
 143         long temp, result;
 144         smp_mb();
 145         __asm__ __volatile__(
 146         "1:     ldl_l %0,%1\n"
 147         "       subl %0,%3,%2\n"
 148         "       subl %0,%3,%0\n"
 149         "       stl_c %0,%1\n"
 150         "       beq %0,2f\n"
 151         ".subsection 2\n"
 152         "2:     br 1b\n"
 153         ".previous"
 154         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 155         :"Ir" (i), "m" (v->counter) : "memory");
 156         smp_mb();
 157         return result;
 158 }
 159
 160 static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
 161 {
 162         long temp, result;
 163         smp_mb();
 164         __asm__ __volatile__(
 165         "1:     ldq_l %0,%1\n"
 166         "       subq %0,%3,%2\n"
 167         "       subq %0,%3,%0\n"
 168         "       stq_c %0,%1\n"
 169         "       beq %0,2f\n"
 170         ".subsection 2\n"
 171         "2:     br 1b\n"
 172         ".previous"
 173         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 174         :"Ir" (i), "m" (v->counter) : "memory");
 175         smp_mb();
 176         return result;
 177 }
 178
 179 #define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 180 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 181
 182 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
 183 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 184
 185 /**
 186  * atomic_add_unless - add unless the number is a given value
 187  * @v: pointer of type atomic_t
 188  * @a: the amount to add to v...
 189  * @u: ...unless v is equal to u.
 190  *
 191  * Atomically adds @a to @v, so long as it was not @u.
 192  * Returns non-zero if @v was not @u, and zero otherwise.
 193  */
 194 static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
 195 {
 196         int c, old;
 197         c = atomic_read(v);
 198         for (;;) {
 199                 if (unlikely(c == (u)))
 200                         break;
 201                 old = atomic_cmpxchg((v), c, c + (a));
 202                 if (likely(old == c))
 203                         break;
 204                 c = old;
 205         }
 206         return c != (u);
 207 }
 208
 209 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 210
 211 /**
 212  * atomic64_add_unless - add unless the number is a given value
 213  * @v: pointer of type atomic64_t
 214  * @a: the amount to add to v...
 215  * @u: ...unless v is equal to u.
 216  *
 217  * Atomically adds @a to @v, so long as it was not @u.
 218  * Returns non-zero if @v was not @u, and zero otherwise.
 219  */
 220 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 221 {
 222         long c, old;
 223         c = atomic64_read(v);
 224         for (;;) {
 225                 if (unlikely(c == (u)))
 226                         break;
 227                 old = atomic64_cmpxchg((v), c, c + (a));
 228                 if (likely(old == c))
 229                         break;
 230                 c = old;
 231         }
 232         return c != (u);
 233 }
 234
 235 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 236
 237 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
 238 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
 239
 240 #define atomic_dec_return(v) atomic_sub_return(1,(v))
 241 #define atomic64_dec_return(v) atomic64_sub_return(1,(v))
 242
 243 #define atomic_inc_return(v) atomic_add_return(1,(v))
 244 #define atomic64_inc_return(v) atomic64_add_return(1,(v))
 245
 246 #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
 247 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)
 248
 249 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
 250 #define atomic64_inc_and_test(v) (atomic64_add_return(1, (v)) == 0)
 251
 252 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
 253 #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
 254
 255 #define atomic_inc(v) atomic_add(1,(v))
 256 #define atomic64_inc(v) atomic64_add(1,(v))
 257
 258 #define atomic_dec(v) atomic_sub(1,(v))
 259 #define atomic64_dec(v) atomic64_sub(1,(v))
 260
 261 #define smp_mb__before_atomic_dec()     smp_mb()
 262 #define smp_mb__after_atomic_dec()      smp_mb()
 263 #define smp_mb__before_atomic_inc()     smp_mb()
 264 #define smp_mb__after_atomic_inc()      smp_mb()
 265
 266 #include <asm-generic/atomic.h>
 267 #endif /* _ALPHA_ATOMIC_H */