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1/* SPDX-License-Identifier: GPL-2.0-only */2 3#ifndef __ASM_GENERIC_BITOPS_GENERIC_NON_ATOMIC_H4#define __ASM_GENERIC_BITOPS_GENERIC_NON_ATOMIC_H5 6#include <linux/bits.h>7#include <asm/barrier.h>8 9#ifndef _LINUX_BITOPS_H10#error only <linux/bitops.h> can be included directly11#endif12 13/*14 * Generic definitions for bit operations, should not be used in regular code15 * directly.16 */17 18/**19 * generic___set_bit - Set a bit in memory20 * @nr: the bit to set21 * @addr: the address to start counting from22 *23 * Unlike set_bit(), this function is non-atomic and may be reordered.24 * If it's called on the same region of memory simultaneously, the effect25 * may be that only one operation succeeds.26 */27static __always_inline void28generic___set_bit(unsigned long nr, volatile unsigned long *addr)29{30 unsigned long mask = BIT_MASK(nr);31 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);32 33 *p |= mask;34}35 36static __always_inline void37generic___clear_bit(unsigned long nr, volatile unsigned long *addr)38{39 unsigned long mask = BIT_MASK(nr);40 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);41 42 *p &= ~mask;43}44 45/**46 * generic___change_bit - Toggle a bit in memory47 * @nr: the bit to change48 * @addr: the address to start counting from49 *50 * Unlike change_bit(), this function is non-atomic and may be reordered.51 * If it's called on the same region of memory simultaneously, the effect52 * may be that only one operation succeeds.53 */54static __always_inline void55generic___change_bit(unsigned long nr, volatile unsigned long *addr)56{57 unsigned long mask = BIT_MASK(nr);58 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);59 60 *p ^= mask;61}62 63/**64 * generic___test_and_set_bit - Set a bit and return its old value65 * @nr: Bit to set66 * @addr: Address to count from67 *68 * This operation is non-atomic and can be reordered.69 * If two examples of this operation race, one can appear to succeed70 * but actually fail. You must protect multiple accesses with a lock.71 */72static __always_inline bool73generic___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)74{75 unsigned long mask = BIT_MASK(nr);76 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);77 unsigned long old = *p;78 79 *p = old | mask;80 return (old & mask) != 0;81}82 83/**84 * generic___test_and_clear_bit - Clear a bit and return its old value85 * @nr: Bit to clear86 * @addr: Address to count from87 *88 * This operation is non-atomic and can be reordered.89 * If two examples of this operation race, one can appear to succeed90 * but actually fail. You must protect multiple accesses with a lock.91 */92static __always_inline bool93generic___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)94{95 unsigned long mask = BIT_MASK(nr);96 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);97 unsigned long old = *p;98 99 *p = old & ~mask;100 return (old & mask) != 0;101}102 103/* WARNING: non atomic and it can be reordered! */104static __always_inline bool105generic___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)106{107 unsigned long mask = BIT_MASK(nr);108 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);109 unsigned long old = *p;110 111 *p = old ^ mask;112 return (old & mask) != 0;113}114 115/**116 * generic_test_bit - Determine whether a bit is set117 * @nr: bit number to test118 * @addr: Address to start counting from119 */120static __always_inline bool121generic_test_bit(unsigned long nr, const volatile unsigned long *addr)122{123 /*124 * Unlike the bitops with the '__' prefix above, this one *is* atomic,125 * so `volatile` must always stay here with no cast-aways. See126 * `Documentation/atomic_bitops.txt` for the details.127 */128 return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));129}130 131/**132 * generic_test_bit_acquire - Determine, with acquire semantics, whether a bit is set133 * @nr: bit number to test134 * @addr: Address to start counting from135 */136static __always_inline bool137generic_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr)138{139 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);140 return 1UL & (smp_load_acquire(p) >> (nr & (BITS_PER_LONG-1)));141}142 143/*144 * const_*() definitions provide good compile-time optimizations when145 * the passed arguments can be resolved at compile time.146 */147#define const___set_bit generic___set_bit148#define const___clear_bit generic___clear_bit149#define const___change_bit generic___change_bit150#define const___test_and_set_bit generic___test_and_set_bit151#define const___test_and_clear_bit generic___test_and_clear_bit152#define const___test_and_change_bit generic___test_and_change_bit153#define const_test_bit_acquire generic_test_bit_acquire154 155/**156 * const_test_bit - Determine whether a bit is set157 * @nr: bit number to test158 * @addr: Address to start counting from159 *160 * A version of generic_test_bit() which discards the `volatile` qualifier to161 * allow a compiler to optimize code harder. Non-atomic and to be called only162 * for testing compile-time constants, e.g. by the corresponding macros, not163 * directly from "regular" code.164 */165static __always_inline bool166const_test_bit(unsigned long nr, const volatile unsigned long *addr)167{168 const unsigned long *p = (const unsigned long *)addr + BIT_WORD(nr);169 unsigned long mask = BIT_MASK(nr);170 unsigned long val = *p;171 172 return !!(val & mask);173}174 175#endif /* __ASM_GENERIC_BITOPS_GENERIC_NON_ATOMIC_H */176