1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 /* 4 * This file provides wrappers with sanitizer instrumentation for bit 5 * locking operations. 6 * 7 * To use this functionality, an arch's bitops.h file needs to define each of 8 * 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_H 12 #define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H 13 14 #include <linux/kasan-checks.h> 15 16 /** 17 * clear_bit_unlock - Clear a bit in memory, for unlock 18 * @nr: the bit to set 19 * @addr: the address to start counting from 20 * 21 * This operation is atomic and provides release barrier semantics. 22 */ 23 static inline void clear_bit_unlock(long nr, volatile unsigned long *addr) 24 { 25 kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); 26 arch_clear_bit_unlock(nr, addr); 27 } 28 29 /** 30 * __clear_bit_unlock - Clears a bit in memory 31 * @nr: Bit to clear 32 * @addr: Address to start counting from 33 * 34 * This is a non-atomic operation but implies a release barrier before the 35 * memory operation. It can be used for an unlock if no other CPUs can 36 * concurrently modify other bits in the word. 37 */ 38 static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) 39 { 40 kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); 41 arch___clear_bit_unlock(nr, addr); 42 } 43 44 /** 45 * test_and_set_bit_lock - Set a bit and return its old value, for lock 46 * @nr: Bit to set 47 * @addr: Address to count from 48 * 49 * This operation is atomic and provides acquire barrier semantics if 50 * the returned value is 0. 51 * It can be used to implement bit locks. 52 */ 53 static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr) 54 { 55 kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); 56 return arch_test_and_set_bit_lock(nr, addr); 57 } 58 59 #if defined(arch_clear_bit_unlock_is_negative_byte) 60 /** 61 * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom 62 * byte is negative, for unlock. 63 * @nr: the bit to clear 64 * @addr: the address to start counting from 65 * 66 * This operation is atomic and provides release barrier semantics. 67 * 68 * This is a bit of a one-trick-pony for the filemap code, which clears 69 * PG_locked and tests PG_waiters, 70 */ 71 static inline bool 72 clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr) 73 { 74 kasan_check_write(addr + BIT_WORD(nr), sizeof(long)); 75 return arch_clear_bit_unlock_is_negative_byte(nr, addr); 76 } 77 /* Let everybody know we have it. */ 78 #define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte 79 #endif 80 81 #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */ 82