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 */ 16static __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 25static __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 */ 43static __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 */ 61static __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 */ 81static __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! */ 93static __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 */ 109static __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