summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/futex/include/atomic.h
blob: 428bcd921bb53dfc0f908d5a85b724f50b46df66 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
/* SPDX-License-Identifier: GPL-2.0-or-later */
/******************************************************************************
 *
 *   Copyright © International Business Machines  Corp., 2009
 *
 * DESCRIPTION
 *      GCC atomic builtin wrappers
 *      http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
 *
 * AUTHOR
 *      Darren Hart <dvhart@linux.intel.com>
 *
 * HISTORY
 *      2009-Nov-17: Initial version by Darren Hart <dvhart@linux.intel.com>
 *
 *****************************************************************************/

#ifndef _ATOMIC_H
#define _ATOMIC_H

typedef struct {
	volatile int val;
} atomic_t;

#define ATOMIC_INITIALIZER { 0 }

/**
 * atomic_cmpxchg() - Atomic compare and exchange
 * @uaddr:	The address of the futex to be modified
 * @oldval:	The expected value of the futex
 * @newval:	The new value to try and assign the futex
 *
 * Return the old value of addr->val.
 */
static inline int
atomic_cmpxchg(atomic_t *addr, int oldval, int newval)
{
	return __sync_val_compare_and_swap(&addr->val, oldval, newval);
}

/**
 * atomic_inc() - Atomic incrememnt
 * @addr:	Address of the variable to increment
 *
 * Return the new value of addr->val.
 */
static inline int
atomic_inc(atomic_t *addr)
{
	return __sync_add_and_fetch(&addr->val, 1);
}

/**
 * atomic_dec() - Atomic decrement
 * @addr:	Address of the variable to decrement
 *
 * Return the new value of addr-val.
 */
static inline int
atomic_dec(atomic_t *addr)
{
	return __sync_sub_and_fetch(&addr->val, 1);
}

/**
 * atomic_set() - Atomic set
 * @addr:	Address of the variable to set
 * @newval:	New value for the atomic_t
 *
 * Return the new value of addr->val.
 */
static inline int
atomic_set(atomic_t *addr, int newval)
{
	addr->val = newval;
	return newval;
}

#endif