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/instrumented.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 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 memory 32 * @nr: Bit to clear 33 * @addr: Address to start counting from 34 * 35 * This is a non-atomic operation but implies a release barrier before the 36 * memory operation. It can be used for an unlock if no other CPUs can 37 * concurrently modify other bits in the word. 38 */ 39 static 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 lock 48 * @nr: Bit to set 49 * @addr: Address to count from 50 * 51 * This operation is atomic and provides acquire barrier semantics if 52 * the returned value is 0. 53 * It can be used to implement bit locks. 54 */ 55 static 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 #if defined(arch_clear_bit_unlock_is_negative_byte) 62 /** 63 * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom 64 * byte is negative, for unlock. 65 * @nr: the bit to clear 66 * @addr: the address to start counting from 67 * 68 * This operation is atomic and provides release barrier semantics. 69 * 70 * This is a bit of a one-trick-pony for the filemap code, which clears 71 * PG_locked and tests PG_waiters, 72 */ 73 static inline bool 74 clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr) 75 { 76 kcsan_release(); 77 instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long)); 78 return arch_clear_bit_unlock_is_negative_byte(nr, addr); 79 } 80 /* Let everybody know we have it. */ 81 #define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte 82 #endif 83 84 #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */ 85