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1 | #ifndef _ASM_X86_SYNC_BITOPS_H |
2 | #define _ASM_X86_SYNC_BITOPS_H | |
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3 | |
4 | /* | |
5 | * Copyright 1992, Linus Torvalds. | |
6 | */ | |
7 | ||
8 | /* | |
9 | * These have to be done with inline assembly: that way the bit-setting | |
10 | * is guaranteed to be atomic. All bit operations return 0 if the bit | |
11 | * was cleared before the operation and != 0 if it was not. | |
12 | * | |
13 | * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). | |
14 | */ | |
15 | ||
26b7fcc4 | 16 | #define ADDR (*(volatile long *)addr) |
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17 | |
18 | /** | |
19 | * sync_set_bit - Atomically set a bit in memory | |
20 | * @nr: the bit to set | |
21 | * @addr: the address to start counting from | |
22 | * | |
23 | * This function is atomic and may not be reordered. See __set_bit() | |
24 | * if you do not require the atomic guarantees. | |
25 | * | |
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26 | * Note that @nr may be almost arbitrarily large; this function is not |
27 | * restricted to acting on a single-word quantity. | |
28 | */ | |
9b710506 | 29 | static inline void sync_set_bit(long nr, volatile unsigned long *addr) |
027a8c7e | 30 | { |
9b710506 | 31 | asm volatile("lock; bts %1,%0" |
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32 | : "+m" (ADDR) |
33 | : "Ir" (nr) | |
34 | : "memory"); | |
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35 | } |
36 | ||
37 | /** | |
38 | * sync_clear_bit - Clears a bit in memory | |
39 | * @nr: Bit to clear | |
40 | * @addr: Address to start counting from | |
41 | * | |
42 | * sync_clear_bit() is atomic and may not be reordered. However, it does | |
43 | * not contain a memory barrier, so if it is used for locking purposes, | |
d00a5692 | 44 | * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic() |
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45 | * in order to ensure changes are visible on other processors. |
46 | */ | |
9b710506 | 47 | static inline void sync_clear_bit(long nr, volatile unsigned long *addr) |
027a8c7e | 48 | { |
9b710506 | 49 | asm volatile("lock; btr %1,%0" |
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50 | : "+m" (ADDR) |
51 | : "Ir" (nr) | |
52 | : "memory"); | |
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53 | } |
54 | ||
55 | /** | |
56 | * sync_change_bit - Toggle a bit in memory | |
57 | * @nr: Bit to change | |
58 | * @addr: Address to start counting from | |
59 | * | |
7800c0c3 | 60 | * sync_change_bit() is atomic and may not be reordered. |
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61 | * Note that @nr may be almost arbitrarily large; this function is not |
62 | * restricted to acting on a single-word quantity. | |
63 | */ | |
9b710506 | 64 | static inline void sync_change_bit(long nr, volatile unsigned long *addr) |
027a8c7e | 65 | { |
9b710506 | 66 | asm volatile("lock; btc %1,%0" |
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67 | : "+m" (ADDR) |
68 | : "Ir" (nr) | |
69 | : "memory"); | |
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70 | } |
71 | ||
72 | /** | |
73 | * sync_test_and_set_bit - Set a bit and return its old value | |
74 | * @nr: Bit to set | |
75 | * @addr: Address to count from | |
76 | * | |
77 | * This operation is atomic and cannot be reordered. | |
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78 | * It also implies a memory barrier. |
79 | */ | |
9b710506 | 80 | static inline int sync_test_and_set_bit(long nr, volatile unsigned long *addr) |
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81 | { |
82 | int oldbit; | |
83 | ||
9b710506 | 84 | asm volatile("lock; bts %2,%1\n\tsbbl %0,%0" |
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85 | : "=r" (oldbit), "+m" (ADDR) |
86 | : "Ir" (nr) : "memory"); | |
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87 | return oldbit; |
88 | } | |
89 | ||
90 | /** | |
91 | * sync_test_and_clear_bit - Clear a bit and return its old value | |
92 | * @nr: Bit to clear | |
93 | * @addr: Address to count from | |
94 | * | |
95 | * This operation is atomic and cannot be reordered. | |
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96 | * It also implies a memory barrier. |
97 | */ | |
9b710506 | 98 | static inline int sync_test_and_clear_bit(long nr, volatile unsigned long *addr) |
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99 | { |
100 | int oldbit; | |
101 | ||
9b710506 | 102 | asm volatile("lock; btr %2,%1\n\tsbbl %0,%0" |
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103 | : "=r" (oldbit), "+m" (ADDR) |
104 | : "Ir" (nr) : "memory"); | |
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105 | return oldbit; |
106 | } | |
107 | ||
108 | /** | |
109 | * sync_test_and_change_bit - Change a bit and return its old value | |
110 | * @nr: Bit to change | |
111 | * @addr: Address to count from | |
112 | * | |
113 | * This operation is atomic and cannot be reordered. | |
114 | * It also implies a memory barrier. | |
115 | */ | |
9b710506 | 116 | static inline int sync_test_and_change_bit(long nr, volatile unsigned long *addr) |
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117 | { |
118 | int oldbit; | |
119 | ||
9b710506 | 120 | asm volatile("lock; btc %2,%1\n\tsbbl %0,%0" |
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121 | : "=r" (oldbit), "+m" (ADDR) |
122 | : "Ir" (nr) : "memory"); | |
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123 | return oldbit; |
124 | } | |
125 | ||
aa040b2f | 126 | #define sync_test_bit(nr, addr) test_bit(nr, addr) |
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127 | |
128 | #undef ADDR | |
129 | ||
1965aae3 | 130 | #endif /* _ASM_X86_SYNC_BITOPS_H */ |