// 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)