arch/parisc/lib/bitops.c

   1 /* atomic.c: atomic operations which got too long to be inlined all over
   2  * the place.
   3  *
   4  * Copyright 1999 Philipp Rumpf (prumpf@tux.org */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/spinlock.h>
   8 #include <asm/system.h>
   9 #include <asm/atomic.h>
  10
  11 #ifdef CONFIG_SMP
  12 spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
  13         [0 ... (ATOMIC_HASH_SIZE-1)]  = SPIN_LOCK_UNLOCKED
  14 };
  15 #endif
  16
  17 spinlock_t __atomic_lock = SPIN_LOCK_UNLOCKED;
  18
  19 #ifndef __LP64__
  20 unsigned long __xchg(unsigned long x, unsigned long *ptr, int size)
  21 {
  22         unsigned long temp, flags;
  23
  24         if (size != sizeof x) {
  25                 printk("__xchg called with bad pointer\n");
  26         }
  27         spin_lock_irqsave(&__atomic_lock, flags);
  28         temp = *ptr;
  29         *ptr = x;
  30         spin_unlock_irqrestore(&__atomic_lock, flags);
  31         return temp;
  32 }
  33 #else
  34 unsigned long __xchg(unsigned long x, unsigned long *ptr, int size)
  35 {
  36         unsigned long temp, flags;
  37         unsigned int *ptr32;
  38
  39         if (size == 8) {
  40 try_long:
  41                 spin_lock_irqsave(&__atomic_lock, flags);
  42                 temp = *ptr;
  43                 *ptr = x;
  44                 spin_unlock_irqrestore(&__atomic_lock, flags);
  45                 return temp;
  46         }
  47         if (size == 4) {
  48                 ptr32 = (unsigned int *)ptr;
  49                 spin_lock_irqsave(&__atomic_lock, flags);
  50                 temp = (unsigned long)*ptr32;
  51                 *ptr32 = (unsigned int)x;
  52                 spin_unlock_irqrestore(&__atomic_lock, flags);
  53                 return temp;
  54         }
  55
  56         printk("__xchg called with bad pointer\n");
  57         goto try_long;
  58 }
  59 #endif