1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <pthread.h>
30#include <linux/futex.h>
31
32#define  SWAP_LOCK_COUNT  32U
33static pthread_mutex_t  _swap_locks[SWAP_LOCK_COUNT];
34
35#define  SWAP_LOCK(addr)   \
36   &_swap_locks[((unsigned)(void *)(addr) >> 3U) % SWAP_LOCK_COUNT]
37
38#if 0
39/*
40 * Only this function is moved to atomic_cmpxchg.S, and
41 * implemented with gUSA framework.
42 */
43int __atomic_cmpxchg(int old, int _new, volatile int *ptr)
44{
45    int result;
46    pthread_mutex_t *lock = SWAP_LOCK(ptr);
47
48    pthread_mutex_lock(lock);
49
50    if (*ptr == old) {
51        *ptr  = _new;
52        result = 0;
53    } else {
54        result = 1;
55    }
56    pthread_mutex_unlock(lock);
57    return result;
58}
59#else
60extern int __atomic_cmpxchg(int old, int _new, volatile int *ptr);
61#endif
62
63int __atomic_swap(int _new, volatile int *ptr)
64{
65    int oldValue;
66    do {
67        oldValue = *ptr;
68    } while (__atomic_cmpxchg(oldValue, _new, ptr));
69    return oldValue;
70}
71
72int __atomic_dec(volatile int *ptr)
73{
74    int oldValue;
75    do {
76        oldValue = *ptr;
77    } while (__atomic_cmpxchg(oldValue, oldValue-1, ptr));
78    return oldValue;
79}
80
81int __atomic_inc(volatile int *ptr)
82{
83    int32_t oldValue;
84    do {
85        oldValue = *ptr;
86    } while (__atomic_cmpxchg(oldValue, oldValue+1, ptr));
87    return oldValue;
88}
89
90extern int futex(volatile void *, int, int, void *, void *, int);
91
92int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout)
93{
94    return futex(ftx, FUTEX_WAIT, val, (void *)timeout, NULL, 0);
95}
96
97int __futex_wake(volatile void *ftx, int count)
98{
99    return futex(ftx, FUTEX_WAKE, count, NULL, NULL, 0);
100}
101
102int __futex_syscall3(volatile void *ftx, int op, int val)
103{
104    return futex(ftx, op, val, NULL, NULL, 0);
105}
106
107int __futex_syscall4(volative void *ftx, int op, int val, const struct timespec *timeout)
108{
109    return futex(ftx, op, val, (void *)timeout, NULL, 0);
110}
111