1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_GENERIC_BITOPS_LOCK_H_
3#define _ASM_GENERIC_BITOPS_LOCK_H_
4
5#include <linux/atomic.h>
6#include <linux/compiler.h>
7#include <asm/barrier.h>
8
9/**
10 * arch_test_and_set_bit_lock - Set a bit and return its old value, for lock
11 * @nr: Bit to set
12 * @addr: Address to count from
13 *
14 * This operation is atomic and provides acquire barrier semantics if
15 * the returned value is 0.
16 * It can be used to implement bit locks.
17 */
18static __always_inline int
19arch_test_and_set_bit_lock(unsigned int nr, volatile unsigned long *p)
20{
21	long old;
22	unsigned long mask = BIT_MASK(nr);
23
24	p += BIT_WORD(nr);
25	if (READ_ONCE(*p) & mask)
26		return 1;
27
28	old = raw_atomic_long_fetch_or_acquire(mask, (atomic_long_t *)p);
29	return !!(old & mask);
30}
31
32
33/**
34 * arch_clear_bit_unlock - Clear a bit in memory, for unlock
35 * @nr: the bit to set
36 * @addr: the address to start counting from
37 *
38 * This operation is atomic and provides release barrier semantics.
39 */
40static __always_inline void
41arch_clear_bit_unlock(unsigned int nr, volatile unsigned long *p)
42{
43	p += BIT_WORD(nr);
44	raw_atomic_long_fetch_andnot_release(BIT_MASK(nr), (atomic_long_t *)p);
45}
46
47/**
48 * arch___clear_bit_unlock - Clear a bit in memory, for unlock
49 * @nr: the bit to set
50 * @addr: the address to start counting from
51 *
52 * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all
53 * the bits in the word are protected by this lock some archs can use weaker
54 * ops to safely unlock.
55 *
56 * See for example x86's implementation.
57 */
58static inline void
59arch___clear_bit_unlock(unsigned int nr, volatile unsigned long *p)
60{
61	unsigned long old;
62
63	p += BIT_WORD(nr);
64	old = READ_ONCE(*p);
65	old &= ~BIT_MASK(nr);
66	raw_atomic_long_set_release((atomic_long_t *)p, old);
67}
68
69#ifndef arch_xor_unlock_is_negative_byte
70static inline bool arch_xor_unlock_is_negative_byte(unsigned long mask,
71		volatile unsigned long *p)
72{
73	long old;
74
75	old = raw_atomic_long_fetch_xor_release(mask, (atomic_long_t *)p);
76	return !!(old & BIT(7));
77}
78#endif
79
80#include <asm-generic/bitops/instrumented-lock.h>
81
82#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
83