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 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
33 unsigned 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
46 unsigned 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
59 #define CMPXCHG(T) \
60 T notrace __cmpxchg_##T(volatile T *ptr, T old, T new) \
61 { \
62 unsigned long flags; \
63 T prev; \
64 \
65 _atomic_spin_lock_irqsave(ptr, flags); \
66 if ((prev = *ptr) == old) \
67 *ptr = new; \
68 _atomic_spin_unlock_irqrestore(ptr, flags); \
69 return prev; \
70 }
71
72 CMPXCHG(u64)
73 CMPXCHG(u32)
74 CMPXCHG(u16)
75 CMPXCHG(u8)
76
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