arch/parisc/include/asm/atomic.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   3  * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
   4  */
   5
   6 #ifndef _ASM_PARISC_ATOMIC_H_
   7 #define _ASM_PARISC_ATOMIC_H_
   8
   9 #include <linux/types.h>
  10 #include <asm/cmpxchg.h>
  11 #include <asm/barrier.h>
  12
  13 /*
  14  * Atomic operations that C can't guarantee us.  Useful for
  15  * resource counting etc..
  16  *
  17  * And probably incredibly slow on parisc.  OTOH, we don't
  18  * have to write any serious assembly.   prumpf
  19  */
  20
  21 #ifdef CONFIG_SMP
  22 #include <asm/spinlock.h>
  23 #include <asm/cache.h>          /* we use L1_CACHE_BYTES */
  24
  25 /* Use an array of spinlocks for our atomic_ts.
  26  * Hash function to index into a different SPINLOCK.
  27  * Since "a" is usually an address, use one spinlock per cacheline.
  28  */
  29 #  define ATOMIC_HASH_SIZE 4
  30 #  define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
  31
  32 extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
  33
  34 /* Can't use raw_spin_lock_irq because of #include problems, so
  35  * this is the substitute */
  36 #define _atomic_spin_lock_irqsave(l,f) do {     \
  37         arch_spinlock_t *s = ATOMIC_HASH(l);            \
  38         local_irq_save(f);                      \
  39         arch_spin_lock(s);                      \
  40 } while(0)
  41
  42 #define _atomic_spin_unlock_irqrestore(l,f) do {        \
  43         arch_spinlock_t *s = ATOMIC_HASH(l);                    \
  44         arch_spin_unlock(s);                            \
  45         local_irq_restore(f);                           \
  46 } while(0)
  47
  48
  49 #else
  50 #  define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
  51 #  define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
  52 #endif
  53
  54 /*
  55  * Note that we need not lock read accesses - aligned word writes/reads
  56  * are atomic, so a reader never sees inconsistent values.
  57  */
  58
  59 static __inline__ void atomic_set(atomic_t *v, int i)
  60 {
  61         unsigned long flags;
  62         _atomic_spin_lock_irqsave(v, flags);
  63
  64         v->counter = i;
  65
  66         _atomic_spin_unlock_irqrestore(v, flags);
  67 }
  68
  69 #define atomic_set_release(v, i)        atomic_set((v), (i))
  70
  71 static __inline__ int atomic_read(const atomic_t *v)
  72 {
  73         return READ_ONCE((v)->counter);
  74 }
  75
  76 /* exported interface */
  77 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
  78 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
  79
  80 /**
  81  * __atomic_add_unless - add unless the number is a given value
  82  * @v: pointer of type atomic_t
  83  * @a: the amount to add to v...
  84  * @u: ...unless v is equal to u.
  85  *
  86  * Atomically adds @a to @v, so long as it was not @u.
  87  * Returns the old value of @v.
  88  */
  89 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
  90 {
  91         int c, old;
  92         c = atomic_read(v);
  93         for (;;) {
  94                 if (unlikely(c == (u)))
  95                         break;
  96                 old = atomic_cmpxchg((v), c, c + (a));
  97                 if (likely(old == c))
  98                         break;
  99                 c = old;
 100         }
 101         return c;
 102 }
 103
 104 #define ATOMIC_OP(op, c_op)                                             \
 105 static __inline__ void atomic_##op(int i, atomic_t *v)                  \
 106 {                                                                       \
 107         unsigned long flags;                                            \
 108                                                                         \
 109         _atomic_spin_lock_irqsave(v, flags);                            \
 110         v->counter c_op i;                                              \
 111         _atomic_spin_unlock_irqrestore(v, flags);                       \
 112 }                                                                       \
 113
 114 #define ATOMIC_OP_RETURN(op, c_op)                                      \
 115 static __inline__ int atomic_##op##_return(int i, atomic_t *v)          \
 116 {                                                                       \
 117         unsigned long flags;                                            \
 118         int ret;                                                        \
 119                                                                         \
 120         _atomic_spin_lock_irqsave(v, flags);                            \
 121         ret = (v->counter c_op i);                                      \
 122         _atomic_spin_unlock_irqrestore(v, flags);                       \
 123                                                                         \
 124         return ret;                                                     \
 125 }
 126
 127 #define ATOMIC_FETCH_OP(op, c_op)                                       \
 128 static __inline__ int atomic_fetch_##op(int i, atomic_t *v)             \
 129 {                                                                       \
 130         unsigned long flags;                                            \
 131         int ret;                                                        \
 132                                                                         \
 133         _atomic_spin_lock_irqsave(v, flags);                            \
 134         ret = v->counter;                                               \
 135         v->counter c_op i;                                              \
 136         _atomic_spin_unlock_irqrestore(v, flags);                       \
 137                                                                         \
 138         return ret;                                                     \
 139 }
 140
 141 #define ATOMIC_OPS(op, c_op)                                            \
 142         ATOMIC_OP(op, c_op)                                             \
 143         ATOMIC_OP_RETURN(op, c_op)                                      \
 144         ATOMIC_FETCH_OP(op, c_op)
 145
 146 ATOMIC_OPS(add, +=)
 147 ATOMIC_OPS(sub, -=)
 148
 149 #undef ATOMIC_OPS
 150 #define ATOMIC_OPS(op, c_op)                                            \
 151         ATOMIC_OP(op, c_op)                                             \
 152         ATOMIC_FETCH_OP(op, c_op)
 153
 154 ATOMIC_OPS(and, &=)
 155 ATOMIC_OPS(or, |=)
 156 ATOMIC_OPS(xor, ^=)
 157
 158 #undef ATOMIC_OPS
 159 #undef ATOMIC_FETCH_OP
 160 #undef ATOMIC_OP_RETURN
 161 #undef ATOMIC_OP
 162
 163 #define atomic_inc(v)   (atomic_add(   1,(v)))
 164 #define atomic_dec(v)   (atomic_add(  -1,(v)))
 165
 166 #define atomic_inc_return(v)    (atomic_add_return(   1,(v)))
 167 #define atomic_dec_return(v)    (atomic_add_return(  -1,(v)))
 168
 169 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
 170
 171 /*
 172  * atomic_inc_and_test - increment and test
 173  * @v: pointer of type atomic_t
 174  *
 175  * Atomically increments @v by 1
 176  * and returns true if the result is zero, or false for all
 177  * other cases.
 178  */
 179 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
 180
 181 #define atomic_dec_and_test(v)  (atomic_dec_return(v) == 0)
 182
 183 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i),(v)) == 0)
 184
 185 #define ATOMIC_INIT(i)  { (i) }
 186
 187 #ifdef CONFIG_64BIT
 188
 189 #define ATOMIC64_INIT(i) { (i) }
 190
 191 #define ATOMIC64_OP(op, c_op)                                           \
 192 static __inline__ void atomic64_##op(s64 i, atomic64_t *v)              \
 193 {                                                                       \
 194         unsigned long flags;                                            \
 195                                                                         \
 196         _atomic_spin_lock_irqsave(v, flags);                            \
 197         v->counter c_op i;                                              \
 198         _atomic_spin_unlock_irqrestore(v, flags);                       \
 199 }                                                                       \
 200
 201 #define ATOMIC64_OP_RETURN(op, c_op)                                    \
 202 static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v)      \
 203 {                                                                       \
 204         unsigned long flags;                                            \
 205         s64 ret;                                                        \
 206                                                                         \
 207         _atomic_spin_lock_irqsave(v, flags);                            \
 208         ret = (v->counter c_op i);                                      \
 209         _atomic_spin_unlock_irqrestore(v, flags);                       \
 210                                                                         \
 211         return ret;                                                     \
 212 }
 213
 214 #define ATOMIC64_FETCH_OP(op, c_op)                                     \
 215 static __inline__ s64 atomic64_fetch_##op(s64 i, atomic64_t *v)         \
 216 {                                                                       \
 217         unsigned long flags;                                            \
 218         s64 ret;                                                        \
 219                                                                         \
 220         _atomic_spin_lock_irqsave(v, flags);                            \
 221         ret = v->counter;                                               \
 222         v->counter c_op i;                                              \
 223         _atomic_spin_unlock_irqrestore(v, flags);                       \
 224                                                                         \
 225         return ret;                                                     \
 226 }
 227
 228 #define ATOMIC64_OPS(op, c_op)                                          \
 229         ATOMIC64_OP(op, c_op)                                           \
 230         ATOMIC64_OP_RETURN(op, c_op)                                    \
 231         ATOMIC64_FETCH_OP(op, c_op)
 232
 233 ATOMIC64_OPS(add, +=)
 234 ATOMIC64_OPS(sub, -=)
 235
 236 #undef ATOMIC64_OPS
 237 #define ATOMIC64_OPS(op, c_op)                                          \
 238         ATOMIC64_OP(op, c_op)                                           \
 239         ATOMIC64_FETCH_OP(op, c_op)
 240
 241 ATOMIC64_OPS(and, &=)
 242 ATOMIC64_OPS(or, |=)
 243 ATOMIC64_OPS(xor, ^=)
 244
 245 #undef ATOMIC64_OPS
 246 #undef ATOMIC64_FETCH_OP
 247 #undef ATOMIC64_OP_RETURN
 248 #undef ATOMIC64_OP
 249
 250 static __inline__ void
 251 atomic64_set(atomic64_t *v, s64 i)
 252 {
 253         unsigned long flags;
 254         _atomic_spin_lock_irqsave(v, flags);
 255
 256         v->counter = i;
 257
 258         _atomic_spin_unlock_irqrestore(v, flags);
 259 }
 260
 261 #define atomic64_set_release(v, i)      atomic64_set((v), (i))
 262
 263 static __inline__ s64
 264 atomic64_read(const atomic64_t *v)
 265 {
 266         return ACCESS_ONCE((v)->counter);
 267 }
 268
 269 #define atomic64_inc(v)         (atomic64_add(   1,(v)))
 270 #define atomic64_dec(v)         (atomic64_add(  -1,(v)))
 271
 272 #define atomic64_inc_return(v)          (atomic64_add_return(   1,(v)))
 273 #define atomic64_dec_return(v)          (atomic64_add_return(  -1,(v)))
 274
 275 #define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
 276
 277 #define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
 278 #define atomic64_dec_and_test(v)        (atomic64_dec_return(v) == 0)
 279 #define atomic64_sub_and_test(i,v)      (atomic64_sub_return((i),(v)) == 0)
 280
 281 /* exported interface */
 282 #define atomic64_cmpxchg(v, o, n) \
 283         ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
 284 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 285
 286 /**
 287  * atomic64_add_unless - add unless the number is a given value
 288  * @v: pointer of type atomic64_t
 289  * @a: the amount to add to v...
 290  * @u: ...unless v is equal to u.
 291  *
 292  * Atomically adds @a to @v, so long as it was not @u.
 293  * Returns the old value of @v.
 294  */
 295 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 296 {
 297         long c, old;
 298         c = atomic64_read(v);
 299         for (;;) {
 300                 if (unlikely(c == (u)))
 301                         break;
 302                 old = atomic64_cmpxchg((v), c, c + (a));
 303                 if (likely(old == c))
 304                         break;
 305                 c = old;
 306         }
 307         return c != (u);
 308 }
 309
 310 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 311
 312 /*
 313  * atomic64_dec_if_positive - decrement by 1 if old value positive
 314  * @v: pointer of type atomic_t
 315  *
 316  * The function returns the old value of *v minus 1, even if
 317  * the atomic variable, v, was not decremented.
 318  */
 319 static inline long atomic64_dec_if_positive(atomic64_t *v)
 320 {
 321         long c, old, dec;
 322         c = atomic64_read(v);
 323         for (;;) {
 324                 dec = c - 1;
 325                 if (unlikely(dec < 0))
 326                         break;
 327                 old = atomic64_cmpxchg((v), c, dec);
 328                 if (likely(old == c))
 329                         break;
 330                 c = old;
 331         }
 332         return dec;
 333 }
 334
 335 #endif /* !CONFIG_64BIT */
 336
 337
 338 #endif /* _ASM_PARISC_ATOMIC_H_ */