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
15arch_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
21unsigned long notrace __xchg64(unsigned long x, volatile 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
33unsigned long notrace __xchg32(int x, volatile 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
46unsigned long notrace __xchg8(char x, volatile 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
59u64 notrace __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
71unsigned long notrace __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}
82
83u8 notrace __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new)
84{
85	unsigned long flags;
86	u8 prev;
87
88	_atomic_spin_lock_irqsave(ptr, flags);
89	if ((prev = *ptr) == old)
90		*ptr = new;
91	_atomic_spin_unlock_irqrestore(ptr, flags);
92	return prev;
93}
94