root/arch/parisc/lib/bitops.c

DEFINITIONS

1. __xchg64
2. __xchg32
3. __xchg8
4. __cmpxchg_u64
5. __cmpxchg_u32

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * bitops.c: atomic operations which got too long to be inlined all over
   4  *      the place.
   5  * 
   6  * Copyright 1999 Philipp Rumpf (prumpf@tux.org)
   7  * Copyright 2000 Grant Grundler (grundler@cup.hp.com)
   8  */
   9 
  10 #include <linux/kernel.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/atomic.h>
  13 
  14 #ifdef CONFIG_SMP
  15 arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
  16         [0 ... (ATOMIC_HASH_SIZE-1)]  = __ARCH_SPIN_LOCK_UNLOCKED
  17 };
  18 #endif
  19 
  20 #ifdef CONFIG_64BIT
  21 unsigned long __xchg64(unsigned long x, unsigned long *ptr)
  22 {
  23         unsigned long temp, flags;
  24 
  25         _atomic_spin_lock_irqsave(ptr, flags);
  26         temp = *ptr;
  27         *ptr = x;
  28         _atomic_spin_unlock_irqrestore(ptr, flags);
  29         return temp;
  30 }
  31 #endif
  32 
  33 unsigned long __xchg32(int x, int *ptr)
  34 {
  35         unsigned long flags;
  36         long temp;
  37 
  38         _atomic_spin_lock_irqsave(ptr, flags);
  39         temp = (long) *ptr;     /* XXX - sign extension wanted? */
  40         *ptr = x;
  41         _atomic_spin_unlock_irqrestore(ptr, flags);
  42         return (unsigned long)temp;
  43 }
  44 
  45 
  46 unsigned long __xchg8(char x, char *ptr)
  47 {
  48         unsigned long flags;
  49         long temp;
  50 
  51         _atomic_spin_lock_irqsave(ptr, flags);
  52         temp = (long) *ptr;     /* XXX - sign extension wanted? */
  53         *ptr = x;
  54         _atomic_spin_unlock_irqrestore(ptr, flags);
  55         return (unsigned long)temp;
  56 }
  57 
  58 
  59 u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new)
  60 {
  61         unsigned long flags;
  62         u64 prev;
  63 
  64         _atomic_spin_lock_irqsave(ptr, flags);
  65         if ((prev = *ptr) == old)
  66                 *ptr = new;
  67         _atomic_spin_unlock_irqrestore(ptr, flags);
  68         return prev;
  69 }
  70 
  71 unsigned long __cmpxchg_u32(volatile unsigned int *ptr, unsigned int old, unsigned int new)
  72 {
  73         unsigned long flags;
  74         unsigned int prev;
  75 
  76         _atomic_spin_lock_irqsave(ptr, flags);
  77         if ((prev = *ptr) == old)
  78                 *ptr = new;
  79         _atomic_spin_unlock_irqrestore(ptr, flags);
  80         return (unsigned long)prev;
  81 }