1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
3 #define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
4
5 #include <asm/types.h>
6
7 /**
8 * __set_bit - Set a bit in memory
9 * @nr: the bit to set
10 * @addr: the address to start counting from
11 *
12 * Unlike set_bit(), this function is non-atomic and may be reordered.
13 * If it's called on the same region of memory simultaneously, the effect
14 * may be that only one operation succeeds.
15 */
16 static inline void __set_bit(int nr, volatile unsigned long *addr)
17 {
18 unsigned long mask = BIT_MASK(nr);
19 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
20
21 *p |= mask;
22 }
23
24 static inline void __clear_bit(int nr, volatile unsigned long *addr)
25 {
26 unsigned long mask = BIT_MASK(nr);
27 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
28
29 *p &= ~mask;
30 }
31
32 /**
33 * __change_bit - Toggle a bit in memory
34 * @nr: the bit to change
35 * @addr: the address to start counting from
36 *
37 * Unlike change_bit(), this function is non-atomic and may be reordered.
38 * If it's called on the same region of memory simultaneously, the effect
39 * may be that only one operation succeeds.
40 */
41 static inline void __change_bit(int nr, volatile unsigned long *addr)
42 {
43 unsigned long mask = BIT_MASK(nr);
44 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
45
46 *p ^= mask;
47 }
48
49 /**
50 * __test_and_set_bit - Set a bit and return its old value
51 * @nr: Bit to set
52 * @addr: Address to count from
53 *
54 * This operation is non-atomic and can be reordered.
55 * If two examples of this operation race, one can appear to succeed
56 * but actually fail. You must protect multiple accesses with a lock.
57 */
58 static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
59 {
60 unsigned long mask = BIT_MASK(nr);
61 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
62 unsigned long old = *p;
63
64 *p = old | mask;
65 return (old & mask) != 0;
66 }
67
68 /**
69 * __test_and_clear_bit - Clear a bit and return its old value
70 * @nr: Bit to clear
71 * @addr: Address to count from
72 *
73 * This operation is non-atomic and can be reordered.
74 * If two examples of this operation race, one can appear to succeed
75 * but actually fail. You must protect multiple accesses with a lock.
76 */
77 static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
78 {
79 unsigned long mask = BIT_MASK(nr);
80 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
81 unsigned long old = *p;
82
83 *p = old & ~mask;
84 return (old & mask) != 0;
85 }
86
87 /* WARNING: non atomic and it can be reordered! */
88 static inline int __test_and_change_bit(int nr,
89 volatile unsigned long *addr)
90 {
91 unsigned long mask = BIT_MASK(nr);
92 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
93 unsigned long old = *p;
94
95 *p = old ^ mask;
96 return (old & mask) != 0;
97 }
98
99 /**
100 * test_bit - Determine whether a bit is set
101 * @nr: bit number to test
102 * @addr: Address to start counting from
103 */
104 static inline int test_bit(int nr, const volatile unsigned long *addr)
105 {
106 return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
107 }
108
109 #endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
110
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