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// SPDX-License-Identifier: GPL-2.0
/*
* bitops.c: atomic operations which got too long to be inlined all over
* the place.
*
* Copyright 1999 Philipp Rumpf (prumpf@tux.org)
* Copyright 2000 Grant Grundler (grundler@cup.hp.com)
*/
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#ifdef CONFIG_SMP
arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
[0 ... (ATOMIC_HASH_SIZE-1)] = __ARCH_SPIN_LOCK_UNLOCKED
};
#endif
#ifdef CONFIG_64BIT
unsigned long notrace __xchg64(unsigned long x, volatile unsigned long *ptr)
{
unsigned long temp, flags;
_atomic_spin_lock_irqsave(ptr, flags);
temp = *ptr;
*ptr = x;
_atomic_spin_unlock_irqrestore(ptr, flags);
return temp;
}
#endif
unsigned long notrace __xchg32(int x, volatile int *ptr)
{
unsigned long flags;
long temp;
_atomic_spin_lock_irqsave(ptr, flags);
temp = (long) *ptr; /* XXX - sign extension wanted? */
*ptr = x;
_atomic_spin_unlock_irqrestore(ptr, flags);
return (unsigned long)temp;
}
unsigned long notrace __xchg8(char x, volatile char *ptr)
{
unsigned long flags;
long temp;
_atomic_spin_lock_irqsave(ptr, flags);
temp = (long) *ptr; /* XXX - sign extension wanted? */
*ptr = x;
_atomic_spin_unlock_irqrestore(ptr, flags);
return (unsigned long)temp;
}
#define CMPXCHG(T) \
T notrace __cmpxchg_##T(volatile T *ptr, T old, T new) \
{ \
unsigned long flags; \
T prev; \
\
_atomic_spin_lock_irqsave(ptr, flags); \
if ((prev = *ptr) == old) \
*ptr = new; \
_atomic_spin_unlock_irqrestore(ptr, flags); \
return prev; \
}
CMPXCHG(u64)
CMPXCHG(u32)
CMPXCHG(u16)
CMPXCHG(u8)
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