diff options
Diffstat (limited to 'src/corelib/thread/qfutex_linux_p.h')
-rw-r--r-- | src/corelib/thread/qfutex_linux_p.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/src/corelib/thread/qfutex_linux_p.h b/src/corelib/thread/qfutex_linux_p.h new file mode 100644 index 0000000000..e114dfca72 --- /dev/null +++ b/src/corelib/thread/qfutex_linux_p.h @@ -0,0 +1,95 @@ +// 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 |