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
__xchg64(unsigned long x,volatile unsigned long * ptr)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
__xchg32(int x,volatile int * ptr)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
__xchg8(char x,volatile char * ptr)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
__cmpxchg_u64(volatile u64 * ptr,u64 old,u64 new)59 u64 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
__cmpxchg_u32(volatile unsigned int * ptr,unsigned int old,unsigned int new)71 unsigned 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
__cmpxchg_u8(volatile u8 * ptr,u8 old,u8 new)83 u8 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