arch/parisc/include/asm/atomic.h

   1 /* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   2  * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
   3  */
   4
   5 #ifndef _ASM_PARISC_ATOMIC_H_
   6 #define _ASM_PARISC_ATOMIC_H_
   7
   8 #include <linux/types.h>
   9 #include <asm/system.h>
  10
  11 /*
  12  * Atomic operations that C can't guarantee us.  Useful for
  13  * resource counting etc..
  14  *
  15  * And probably incredibly slow on parisc.  OTOH, we don't
  16  * have to write any serious assembly.   prumpf
  17  */
  18
  19 #ifdef CONFIG_SMP
  20 #include <asm/spinlock.h>
  21 #include <asm/cache.h>          /* we use L1_CACHE_BYTES */
  22
  23 /* Use an array of spinlocks for our atomic_ts.
  24  * Hash function to index into a different SPINLOCK.
  25  * Since "a" is usually an address, use one spinlock per cacheline.
  26  */
  27 #  define ATOMIC_HASH_SIZE 4
  28 #  define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
  29
  30 extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
  31
  32 /* Can't use raw_spin_lock_irq because of #include problems, so
  33  * this is the substitute */
  34 #define _atomic_spin_lock_irqsave(l,f) do {     \
  35         arch_spinlock_t *s = ATOMIC_HASH(l);            \
  36         local_irq_save(f);                      \
  37         arch_spin_lock(s);                      \
  38 } while(0)
  39
  40 #define _atomic_spin_unlock_irqrestore(l,f) do {        \
  41         arch_spinlock_t *s = ATOMIC_HASH(l);                    \
  42         arch_spin_unlock(s);                            \
  43         local_irq_restore(f);                           \
  44 } while(0)
  45
  46
  47 #else
  48 #  define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
  49 #  define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
  50 #endif
  51
  52 /* This should get optimized out since it's never called.
  53 ** Or get a link error if xchg is used "wrong".
  54 */
  55 extern void __xchg_called_with_bad_pointer(void);
  56
  57
  58 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */
  59 extern unsigned long __xchg8(char, char *);
  60 extern unsigned long __xchg32(int, int *);
  61 #ifdef CONFIG_64BIT
  62 extern unsigned long __xchg64(unsigned long, unsigned long *);
  63 #endif
  64
  65 /* optimizer better get rid of switch since size is a constant */
  66 static __inline__ unsigned long
  67 __xchg(unsigned long x, __volatile__ void * ptr, int size)
  68 {
  69         switch(size) {
  70 #ifdef CONFIG_64BIT
  71         case 8: return __xchg64(x,(unsigned long *) ptr);
  72 #endif
  73         case 4: return __xchg32((int) x, (int *) ptr);
  74         case 1: return __xchg8((char) x, (char *) ptr);
  75         }
  76         __xchg_called_with_bad_pointer();
  77         return x;
  78 }
  79
  80
  81 /*
  82 ** REVISIT - Abandoned use of LDCW in xchg() for now:
  83 ** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
  84 ** o and while we are at it, could CONFIG_64BIT code use LDCD too?
  85 **
  86 **      if (__builtin_constant_p(x) && (x == NULL))
  87 **              if (((unsigned long)p & 0xf) == 0)
  88 **                      return __ldcw(p);
  89 */
  90 #define xchg(ptr,x) \
  91         ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  92
  93
  94 #define __HAVE_ARCH_CMPXCHG     1
  95
  96 /* bug catcher for when unsupported size is used - won't link */
  97 extern void __cmpxchg_called_with_bad_pointer(void);
  98
  99 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
 100 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, unsigned int new_);
 101 extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new_);
 102
 103 /* don't worry...optimizer will get rid of most of this */
 104 static __inline__ unsigned long
 105 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
 106 {
 107         switch(size) {
 108 #ifdef CONFIG_64BIT
 109         case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
 110 #endif
 111         case 4: return __cmpxchg_u32((unsigned int *)ptr, (unsigned int) old, (unsigned int) new_);
 112         }
 113         __cmpxchg_called_with_bad_pointer();
 114         return old;
 115 }
 116
 117 #define cmpxchg(ptr,o,n)                                                 \
 118   ({                                                                     \
 119      __typeof__(*(ptr)) _o_ = (o);                                       \
 120      __typeof__(*(ptr)) _n_ = (n);                                       \
 121      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
 122                                     (unsigned long)_n_, sizeof(*(ptr))); \
 123   })
 124
 125 #include <asm-generic/cmpxchg-local.h>
 126
 127 static inline unsigned long __cmpxchg_local(volatile void *ptr,
 128                                       unsigned long old,
 129                                       unsigned long new_, int size)
 130 {
 131         switch (size) {
 132 #ifdef CONFIG_64BIT
 133         case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
 134 #endif
 135         case 4: return __cmpxchg_u32(ptr, old, new_);
 136         default:
 137                 return __cmpxchg_local_generic(ptr, old, new_, size);
 138         }
 139 }
 140
 141 /*
 142  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 143  * them available.
 144  */
 145 #define cmpxchg_local(ptr, o, n)                                        \
 146         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 147                         (unsigned long)(n), sizeof(*(ptr))))
 148 #ifdef CONFIG_64BIT
 149 #define cmpxchg64_local(ptr, o, n)                                      \
 150   ({                                                                    \
 151         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 152         cmpxchg_local((ptr), (o), (n));                                 \
 153   })
 154 #else
 155 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 156 #endif
 157
 158 /*
 159  * Note that we need not lock read accesses - aligned word writes/reads
 160  * are atomic, so a reader never sees inconsistent values.
 161  */
 162
 163 /* It's possible to reduce all atomic operations to either
 164  * __atomic_add_return, atomic_set and atomic_read (the latter
 165  * is there only for consistency).
 166  */
 167
 168 static __inline__ int __atomic_add_return(int i, atomic_t *v)
 169 {
 170         int ret;
 171         unsigned long flags;
 172         _atomic_spin_lock_irqsave(v, flags);
 173
 174         ret = (v->counter += i);
 175
 176         _atomic_spin_unlock_irqrestore(v, flags);
 177         return ret;
 178 }
 179
 180 static __inline__ void atomic_set(atomic_t *v, int i)
 181 {
 182         unsigned long flags;
 183         _atomic_spin_lock_irqsave(v, flags);
 184
 185         v->counter = i;
 186
 187         _atomic_spin_unlock_irqrestore(v, flags);
 188 }
 189
 190 static __inline__ int atomic_read(const atomic_t *v)
 191 {
 192         return (*(volatile int *)&(v)->counter);
 193 }
 194
 195 /* exported interface */
 196 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
 197 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 198
 199 /**
 200  * __atomic_add_unless - add unless the number is a given value
 201  * @v: pointer of type atomic_t
 202  * @a: the amount to add to v...
 203  * @u: ...unless v is equal to u.
 204  *
 205  * Atomically adds @a to @v, so long as it was not @u.
 206  * Returns the old value of @v.
 207  */
 208 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
 209 {
 210         int c, old;
 211         c = atomic_read(v);
 212         for (;;) {
 213                 if (unlikely(c == (u)))
 214                         break;
 215                 old = atomic_cmpxchg((v), c, c + (a));
 216                 if (likely(old == c))
 217                         break;
 218                 c = old;
 219         }
 220         return c;
 221 }
 222
 223
 224 #define atomic_add(i,v) ((void)(__atomic_add_return( (i),(v))))
 225 #define atomic_sub(i,v) ((void)(__atomic_add_return(-(i),(v))))
 226 #define atomic_inc(v)   ((void)(__atomic_add_return(   1,(v))))
 227 #define atomic_dec(v)   ((void)(__atomic_add_return(  -1,(v))))
 228
 229 #define atomic_add_return(i,v)  (__atomic_add_return( (i),(v)))
 230 #define atomic_sub_return(i,v)  (__atomic_add_return(-(i),(v)))
 231 #define atomic_inc_return(v)    (__atomic_add_return(   1,(v)))
 232 #define atomic_dec_return(v)    (__atomic_add_return(  -1,(v)))
 233
 234 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
 235
 236 /*
 237  * atomic_inc_and_test - increment and test
 238  * @v: pointer of type atomic_t
 239  *
 240  * Atomically increments @v by 1
 241  * and returns true if the result is zero, or false for all
 242  * other cases.
 243  */
 244 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
 245
 246 #define atomic_dec_and_test(v)  (atomic_dec_return(v) == 0)
 247
 248 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i),(v)) == 0)
 249
 250 #define ATOMIC_INIT(i)  ((atomic_t) { (i) })
 251
 252 #define smp_mb__before_atomic_dec()     smp_mb()
 253 #define smp_mb__after_atomic_dec()      smp_mb()
 254 #define smp_mb__before_atomic_inc()     smp_mb()
 255 #define smp_mb__after_atomic_inc()      smp_mb()
 256
 257 #ifdef CONFIG_64BIT
 258
 259 #define ATOMIC64_INIT(i) ((atomic64_t) { (i) })
 260
 261 static __inline__ s64
 262 __atomic64_add_return(s64 i, atomic64_t *v)
 263 {
 264         s64 ret;
 265         unsigned long flags;
 266         _atomic_spin_lock_irqsave(v, flags);
 267
 268         ret = (v->counter += i);
 269
 270         _atomic_spin_unlock_irqrestore(v, flags);
 271         return ret;
 272 }
 273
 274 static __inline__ void
 275 atomic64_set(atomic64_t *v, s64 i)
 276 {
 277         unsigned long flags;
 278         _atomic_spin_lock_irqsave(v, flags);
 279
 280         v->counter = i;
 281
 282         _atomic_spin_unlock_irqrestore(v, flags);
 283 }
 284
 285 static __inline__ s64
 286 atomic64_read(const atomic64_t *v)
 287 {
 288         return (*(volatile long *)&(v)->counter);
 289 }
 290
 291 #define atomic64_add(i,v)       ((void)(__atomic64_add_return( ((s64)(i)),(v))))
 292 #define atomic64_sub(i,v)       ((void)(__atomic64_add_return(-((s64)(i)),(v))))
 293 #define atomic64_inc(v)         ((void)(__atomic64_add_return(   1,(v))))
 294 #define atomic64_dec(v)         ((void)(__atomic64_add_return(  -1,(v))))
 295
 296 #define atomic64_add_return(i,v)        (__atomic64_add_return( ((s64)(i)),(v)))
 297 #define atomic64_sub_return(i,v)        (__atomic64_add_return(-((s64)(i)),(v)))
 298 #define atomic64_inc_return(v)          (__atomic64_add_return(   1,(v)))
 299 #define atomic64_dec_return(v)          (__atomic64_add_return(  -1,(v)))
 300
 301 #define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
 302
 303 #define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
 304 #define atomic64_dec_and_test(v)        (atomic64_dec_return(v) == 0)
 305 #define atomic64_sub_and_test(i,v)      (atomic64_sub_return((i),(v)) == 0)
 306
 307 /* exported interface */
 308 #define atomic64_cmpxchg(v, o, n) \
 309         ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
 310 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
 311
 312 /**
 313  * atomic64_add_unless - add unless the number is a given value
 314  * @v: pointer of type atomic64_t
 315  * @a: the amount to add to v...
 316  * @u: ...unless v is equal to u.
 317  *
 318  * Atomically adds @a to @v, so long as it was not @u.
 319  * Returns the old value of @v.
 320  */
 321 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 322 {
 323         long c, old;
 324         c = atomic64_read(v);
 325         for (;;) {
 326                 if (unlikely(c == (u)))
 327                         break;
 328                 old = atomic64_cmpxchg((v), c, c + (a));
 329                 if (likely(old == c))
 330                         break;
 331                 c = old;
 332         }
 333         return c != (u);
 334 }
 335
 336 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 337
 338 #endif /* !CONFIG_64BIT */
 339
 340
 341 #endif /* _ASM_PARISC_ATOMIC_H_ */