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1/* SPDX-License-Identifier: GPL-2.0 */2 3/*4 * This file provides wrappers with sanitizer instrumentation for bit5 * locking operations.6 *7 * To use this functionality, an arch's bitops.h file needs to define each of8 * the below bit operations with an arch_ prefix (e.g. arch_set_bit(),9 * arch___set_bit(), etc.).10 */11#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H12#define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H13 14#include <linux/instrumented.h>15 16/**17 * clear_bit_unlock - Clear a bit in memory, for unlock18 * @nr: the bit to set19 * @addr: the address to start counting from20 *21 * This operation is atomic and provides release barrier semantics.22 */23static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)24{25 kcsan_release();26 instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));27 arch_clear_bit_unlock(nr, addr);28}29 30/**31 * __clear_bit_unlock - Clears a bit in memory32 * @nr: Bit to clear33 * @addr: Address to start counting from34 *35 * This is a non-atomic operation but implies a release barrier before the36 * memory operation. It can be used for an unlock if no other CPUs can37 * concurrently modify other bits in the word.38 */39static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)40{41 kcsan_release();42 instrument_write(addr + BIT_WORD(nr), sizeof(long));43 arch___clear_bit_unlock(nr, addr);44}45 46/**47 * test_and_set_bit_lock - Set a bit and return its old value, for lock48 * @nr: Bit to set49 * @addr: Address to count from50 *51 * This operation is atomic and provides acquire barrier semantics if52 * the returned value is 0.53 * It can be used to implement bit locks.54 */55static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)56{57 instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long));58 return arch_test_and_set_bit_lock(nr, addr);59}60 61/**62 * xor_unlock_is_negative_byte - XOR a single byte in memory and test if63 * it is negative, for unlock.64 * @mask: Change the bits which are set in this mask.65 * @addr: The address of the word containing the byte to change.66 *67 * Changes some of bits 0-6 in the word pointed to by @addr.68 * This operation is atomic and provides release barrier semantics.69 * Used to optimise some folio operations which are commonly paired70 * with an unlock or end of writeback. Bit 7 is used as PG_waiters to71 * indicate whether anybody is waiting for the unlock.72 *73 * Return: Whether the top bit of the byte is set.74 */75static inline bool xor_unlock_is_negative_byte(unsigned long mask,76 volatile unsigned long *addr)77{78 kcsan_release();79 instrument_atomic_write(addr, sizeof(long));80 return arch_xor_unlock_is_negative_byte(mask, addr);81}82#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */83