1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_SYNC_BITOPS_H
3 #define _ASM_X86_SYNC_BITOPS_H
4
5 /*
6 * Copyright 1992, Linus Torvalds.
7 */
8
9 /*
10 * These have to be done with inline assembly: that way the bit-setting
11 * is guaranteed to be atomic. All bit operations return 0 if the bit
12 * was cleared before the operation and != 0 if it was not.
13 *
14 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
15 */
16
17 #include <asm/rmwcc.h>
18
19 #define ADDR (*(volatile long *)addr)
20
21 /**
22 * sync_set_bit - Atomically set a bit in memory
23 * @nr: the bit to set
24 * @addr: the address to start counting from
25 *
26 * This function is atomic and may not be reordered. See __set_bit()
27 * if you do not require the atomic guarantees.
28 *
29 * Note that @nr may be almost arbitrarily large; this function is not
30 * restricted to acting on a single-word quantity.
31 */
32 static inline void sync_set_bit(long nr, volatile unsigned long *addr)
33 {
34 asm volatile("lock; " __ASM_SIZE(bts) " %1,%0"
35 : "+m" (ADDR)
36 : "Ir" (nr)
37 : "memory");
38 }
39
40 /**
41 * sync_clear_bit - Clears a bit in memory
42 * @nr: Bit to clear
43 * @addr: Address to start counting from
44 *
45 * sync_clear_bit() is atomic and may not be reordered. However, it does
46 * not contain a memory barrier, so if it is used for locking purposes,
47 * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic()
48 * in order to ensure changes are visible on other processors.
49 */
50 static inline void sync_clear_bit(long nr, volatile unsigned long *addr)
51 {
52 asm volatile("lock; " __ASM_SIZE(btr) " %1,%0"
53 : "+m" (ADDR)
54 : "Ir" (nr)
55 : "memory");
56 }
57
58 /**
59 * sync_change_bit - Toggle a bit in memory
60 * @nr: Bit to change
61 * @addr: Address to start counting from
62 *
63 * sync_change_bit() is atomic and may not be reordered.
64 * Note that @nr may be almost arbitrarily large; this function is not
65 * restricted to acting on a single-word quantity.
66 */
67 static inline void sync_change_bit(long nr, volatile unsigned long *addr)
68 {
69 asm volatile("lock; " __ASM_SIZE(btc) " %1,%0"
70 : "+m" (ADDR)
71 : "Ir" (nr)
72 : "memory");
73 }
74
75 /**
76 * sync_test_and_set_bit - Set a bit and return its old value
77 * @nr: Bit to set
78 * @addr: Address to count from
79 *
80 * This operation is atomic and cannot be reordered.
81 * It also implies a memory barrier.
82 */
83 static inline bool sync_test_and_set_bit(long nr, volatile unsigned long *addr)
84 {
85 return GEN_BINARY_RMWcc("lock; " __ASM_SIZE(bts), *addr, c, "Ir", nr);
86 }
87
88 /**
89 * sync_test_and_clear_bit - Clear a bit and return its old value
90 * @nr: Bit to clear
91 * @addr: Address to count from
92 *
93 * This operation is atomic and cannot be reordered.
94 * It also implies a memory barrier.
95 */
96 static inline int sync_test_and_clear_bit(long nr, volatile unsigned long *addr)
97 {
98 return GEN_BINARY_RMWcc("lock; " __ASM_SIZE(btr), *addr, c, "Ir", nr);
99 }
100
101 /**
102 * sync_test_and_change_bit - Change a bit and return its old value
103 * @nr: Bit to change
104 * @addr: Address to count from
105 *
106 * This operation is atomic and cannot be reordered.
107 * It also implies a memory barrier.
108 */
109 static inline int sync_test_and_change_bit(long nr, volatile unsigned long *addr)
110 {
111 return GEN_BINARY_RMWcc("lock; " __ASM_SIZE(btc), *addr, c, "Ir", nr);
112 }
113
114 #define sync_test_bit(nr, addr) test_bit(nr, addr)
115
116 #undef ADDR
117
118 #endif /* _ASM_X86_SYNC_BITOPS_H */