name : instrumented-lock.h /* SPDX-License-Identifier: GPL-2.0 */ /* * This file provides wrappers with sanitizer instrumentation for bit * locking operations. * * To use this functionality, an arch's bitops.h file needs to define each of * the below bit operations with an arch_ prefix (e.g. arch_set_bit(), * arch___set_bit(), etc.). */ #ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H #define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H #include <linux/instrumented.h> /** * clear_bit_unlock - Clear a bit in memory, for unlock * @nr: the bit to set * @addr: the address to start counting from * * This operation is atomic and provides release barrier semantics. */ static inline void clear_bit_unlock(long nr, volatile unsigned long *addr) { kcsan_release(); instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long)); arch_clear_bit_unlock(nr, addr); } /** * __clear_bit_unlock - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * * This is a non-atomic operation but implies a release barrier before the * memory operation. It can be used for an unlock if no other CPUs can * concurrently modify other bits in the word. */ static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) { kcsan_release(); instrument_write(addr + BIT_WORD(nr), sizeof(long)); arch___clear_bit_unlock(nr, addr); } /** * test_and_set_bit_lock - Set a bit and return its old value, for lock * @nr: Bit to set * @addr: Address to count from * * This operation is atomic and provides acquire barrier semantics if * the returned value is 0. * It can be used to implement bit locks. */ static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr) { instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long)); return arch_test_and_set_bit_lock(nr, addr); } /** * xor_unlock_is_negative_byte - XOR a single byte in memory and test if * it is negative, for unlock. * @mask: Change the bits which are set in this mask. * @addr: The address of the word containing the byte to change. * * Changes some of bits 0-6 in the word pointed to by @addr. * This operation is atomic and provides release barrier semantics. * Used to optimise some folio operations which are commonly paired * with an unlock or end of writeback. Bit 7 is used as PG_waiters to * indicate whether anybody is waiting for the unlock. * * Return: Whether the top bit of the byte is set. */ static inline bool xor_unlock_is_negative_byte(unsigned long mask, volatile unsigned long *addr) { kcsan_release(); instrument_atomic_write(addr, sizeof(long)); return arch_xor_unlock_is_negative_byte(mask, addr); } #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */