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/* 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 */
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