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