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 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 */
__clear_bit_unlock(long nr,volatile unsigned long * addr)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 */
test_and_set_bit_lock(long nr,volatile unsigned long * addr)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
clear_bit_unlock_is_negative_byte(long nr,volatile unsigned long * addr)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