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 */
clear_bit_unlock(long nr,volatile unsigned long * addr)23 static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
24 {
25 instrument_atomic_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 */
__clear_bit_unlock(long nr,volatile unsigned long * addr)38 static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
39 {
40 instrument_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 */
test_and_set_bit_lock(long nr,volatile unsigned long * addr)53 static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
54 {
55 instrument_atomic_read_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
clear_bit_unlock_is_negative_byte(long nr,volatile unsigned long * addr)72 clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
73 {
74 instrument_atomic_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