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