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 <linux/bits.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 __always_inline void
17 ___set_bit(unsigned long nr, volatile unsigned long *addr)
18 {
19 unsigned long mask = BIT_MASK(nr);
20 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
21
22 *p |= mask;
23 }
24
25 static __always_inline void
26 ___clear_bit(unsigned long nr, volatile unsigned long *addr)
27 {
28 unsigned long mask = BIT_MASK(nr);
29 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
30
31 *p &= ~mask;
32 }
33
34 /**
35 * ___change_bit - Toggle a bit in memory
36 * @nr: the bit to change
37 * @addr: the address to start counting from
38 *
39 * Unlike change_bit(), this function is non-atomic and may be reordered.
40 * If it's called on the same region of memory simultaneously, the effect
41 * may be that only one operation succeeds.
42 */
43 static __always_inline void
44 ___change_bit(unsigned long nr, volatile unsigned long *addr)
45 {
46 unsigned long mask = BIT_MASK(nr);
47 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
48
49 *p ^= mask;
50 }
51
52 /**
53 * ___test_and_set_bit - Set a bit and return its old value
54 * @nr: Bit to set
55 * @addr: Address to count from
56 *
57 * This operation is non-atomic and can be reordered.
58 * If two examples of this operation race, one can appear to succeed
59 * but actually fail. You must protect multiple accesses with a lock.
60 */
61 static __always_inline bool
62 ___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
63 {
64 unsigned long mask = BIT_MASK(nr);
65 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
66 unsigned long old = *p;
67
68 *p = old | mask;
69 return (old & mask) != 0;
70 }
71
72 /**
73 * ___test_and_clear_bit - Clear a bit and return its old value
74 * @nr: Bit to clear
75 * @addr: Address to count from
76 *
77 * This operation is non-atomic and can be reordered.
78 * If two examples of this operation race, one can appear to succeed
79 * but actually fail. You must protect multiple accesses with a lock.
80 */
81 static __always_inline bool
82 ___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
83 {
84 unsigned long mask = BIT_MASK(nr);
85 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
86 unsigned long old = *p;
87
88 *p = old & ~mask;
89 return (old & mask) != 0;
90 }
91
92 /* WARNING: non atomic and it can be reordered! */
93 static __always_inline bool
94 ___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
95 {
96 unsigned long mask = BIT_MASK(nr);
97 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
98 unsigned long old = *p;
99
100 *p = old ^ mask;
101 return (old & mask) != 0;
102 }
103
104 /**
105 * _test_bit - Determine whether a bit is set
106 * @nr: bit number to test
107 * @addr: Address to start counting from
108 */
109 static __always_inline bool
110 _test_bit(unsigned long nr, const volatile unsigned long *addr)
111 {
112 return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
113 }
114
115 #endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
116
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