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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
// Copyright (C) 2023 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QFUTEX_LINUX_P_H
#define QFUTEX_LINUX_P_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
#include <private/qcore_unix_p.h>
#include <qdeadlinetimer.h>
#include <qtsan_impl.h>
#include <asm/unistd.h>
#include <errno.h>
#include <limits.h>
#include <linux/futex.h>
#include <sys/syscall.h>
#include <unistd.h>
// RISC-V does not supply __NR_futex
#ifndef __NR_futex
# define __NR_futex __NR_futex_time64
#endif
#define QT_ALWAYS_USE_FUTEX
QT_BEGIN_NAMESPACE
namespace QtLinuxFutex {
constexpr inline bool futexAvailable() { return true; }
inline int _q_futex(int *addr, int op, int val, quintptr val2 = 0,
int *addr2 = nullptr, int val3 = 0) noexcept
{
QtTsan::futexRelease(addr, addr2);
// we use __NR_futex because some libcs (like Android's bionic) don't
// provide SYS_futex etc.
int result = syscall(__NR_futex, addr, op | FUTEX_PRIVATE_FLAG, val, val2, addr2, val3);
QtTsan::futexAcquire(addr, addr2);
return result;
}
template <typename T> int *addr(T *ptr)
{
int *int_addr = reinterpret_cast<int *>(ptr);
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
if (sizeof(T) > sizeof(int))
int_addr++; //We want a pointer to the least significant half
#endif
return int_addr;
}
template <typename Atomic>
inline void futexWait(Atomic &futex, typename Atomic::Type expectedValue)
{
_q_futex(addr(&futex), FUTEX_WAIT, qintptr(expectedValue));
}
template <typename Atomic>
inline bool futexWait(Atomic &futex, typename Atomic::Type expectedValue, QDeadlineTimer deadline)
{
auto timeout = deadline.deadline<std::chrono::steady_clock>().time_since_epoch();
struct timespec ts = durationToTimespec(timeout);
int r = _q_futex(addr(&futex), FUTEX_WAIT_BITSET, qintptr(expectedValue), quintptr(&ts),
nullptr, FUTEX_BITSET_MATCH_ANY);
return r == 0 || errno != ETIMEDOUT;
}
template <typename Atomic> inline void futexWakeOne(Atomic &futex)
{
_q_futex(addr(&futex), FUTEX_WAKE, 1);
}
template <typename Atomic> inline void futexWakeAll(Atomic &futex)
{
_q_futex(addr(&futex), FUTEX_WAKE, INT_MAX);
}
template <typename Atomic> inline
void futexWakeOp(Atomic &futex1, int wake1, int wake2, Atomic &futex2, quint32 op)
{
_q_futex(addr(&futex1), FUTEX_WAKE_OP, wake1, wake2, addr(&futex2), op);
}} // namespace QtLinuxFutex
namespace QtFutex = QtLinuxFutex;
QT_END_NAMESPACE
#endif // QFUTEX_LINUX_P_H
|
