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Diffstat (limited to '')
| -rw-r--r-- | src/VBox/Runtime/r0drv/linux/waitqueue-r0drv-linux.h | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/src/VBox/Runtime/r0drv/linux/waitqueue-r0drv-linux.h b/src/VBox/Runtime/r0drv/linux/waitqueue-r0drv-linux.h new file mode 100644 index 00000000..4ef87a59 --- /dev/null +++ b/src/VBox/Runtime/r0drv/linux/waitqueue-r0drv-linux.h @@ -0,0 +1,292 @@ +/* $Id: waitqueue-r0drv-linux.h $ */ +/** @file + * IPRT - Linux Ring-0 Driver Helpers for Abstracting Wait Queues, + */ + +/* + * Copyright (C) 2006-2019 Oracle Corporation + * + * This file is part of VirtualBox Open Source Edition (OSE), as + * available from http://www.virtualbox.org. This file is free software; + * you can redistribute it and/or modify it under the terms of the GNU + * General Public License (GPL) as published by the Free Software + * Foundation, in version 2 as it comes in the "COPYING" file of the + * VirtualBox OSE distribution. VirtualBox OSE is distributed in the + * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL) only, as it comes in the "COPYING.CDDL" file of the + * VirtualBox OSE distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + */ + +#ifndef IPRT_INCLUDED_SRC_r0drv_linux_waitqueue_r0drv_linux_h +#define IPRT_INCLUDED_SRC_r0drv_linux_waitqueue_r0drv_linux_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include "the-linux-kernel.h" + +#include <iprt/asm-math.h> +#include <iprt/err.h> +#include <iprt/string.h> +#include <iprt/time.h> + +/** The resolution (nanoseconds) specified when using + * schedule_hrtimeout_range. */ +#define RTR0SEMLNXWAIT_RESOLUTION 50000 + + +/** + * Kernel mode Linux wait state structure. + */ +typedef struct RTR0SEMLNXWAIT +{ + /** The wait queue entry. */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 12, 14) /* 4.13.0 and openSUSE */ + wait_queue_entry_t WaitQE; +#else + wait_queue_t WaitQE; +#endif + /** The absolute timeout given as nano seconds since the start of the + * monotonic clock. */ + uint64_t uNsAbsTimeout; + /** The timeout in nano seconds relative to the start of the wait. */ + uint64_t cNsRelTimeout; + /** The native timeout value. */ + union + { +#ifdef IPRT_LINUX_HAS_HRTIMER + /** The timeout when fHighRes is true. Absolute, so no updating. */ + ktime_t KtTimeout; +#endif + /** The timeout when fHighRes is false. Updated after waiting. */ + long lTimeout; + } u; + /** Set if we use high resolution timeouts. */ + bool fHighRes; + /** Set if it's an indefinite wait. */ + bool fIndefinite; + /** Set if we've already timed out. + * Set by rtR0SemLnxWaitDoIt and read by rtR0SemLnxWaitHasTimedOut. */ + bool fTimedOut; + /** TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE. */ + int iWaitState; + /** The wait queue. */ + wait_queue_head_t *pWaitQueue; +} RTR0SEMLNXWAIT; +/** Pointer to a linux wait state. */ +typedef RTR0SEMLNXWAIT *PRTR0SEMLNXWAIT; + + +/** + * Initializes a wait. + * + * The caller MUST check the wait condition BEFORE calling this function or the + * timeout logic will be flawed. + * + * @returns VINF_SUCCESS or VERR_TIMEOUT. + * @param pWait The wait structure. + * @param fFlags The wait flags. + * @param uTimeout The timeout. + * @param pWaitQueue The wait queue head. + */ +DECLINLINE(int) rtR0SemLnxWaitInit(PRTR0SEMLNXWAIT pWait, uint32_t fFlags, uint64_t uTimeout, + wait_queue_head_t *pWaitQueue) +{ + /* + * Process the flags and timeout. + */ + if (!(fFlags & RTSEMWAIT_FLAGS_INDEFINITE)) + { +/** @todo optimize: millisecs -> nanosecs -> millisec -> jiffies */ + if (fFlags & RTSEMWAIT_FLAGS_MILLISECS) + uTimeout = uTimeout < UINT64_MAX / RT_US_1SEC * RT_US_1SEC + ? uTimeout * RT_US_1SEC + : UINT64_MAX; + if (uTimeout == UINT64_MAX) + fFlags |= RTSEMWAIT_FLAGS_INDEFINITE; + else + { + uint64_t u64Now; + if (fFlags & RTSEMWAIT_FLAGS_RELATIVE) + { + if (uTimeout == 0) + return VERR_TIMEOUT; + + u64Now = RTTimeSystemNanoTS(); + pWait->cNsRelTimeout = uTimeout; + pWait->uNsAbsTimeout = u64Now + uTimeout; + if (pWait->uNsAbsTimeout < u64Now) /* overflow */ + fFlags |= RTSEMWAIT_FLAGS_INDEFINITE; + } + else + { + u64Now = RTTimeSystemNanoTS(); + if (u64Now >= uTimeout) + return VERR_TIMEOUT; + + pWait->cNsRelTimeout = uTimeout - u64Now; + pWait->uNsAbsTimeout = uTimeout; + } + } + } + + if (!(fFlags & RTSEMWAIT_FLAGS_INDEFINITE)) + { + pWait->fIndefinite = false; +#ifdef IPRT_LINUX_HAS_HRTIMER + if ( (fFlags & (RTSEMWAIT_FLAGS_NANOSECS | RTSEMWAIT_FLAGS_ABSOLUTE)) + || pWait->cNsRelTimeout < RT_NS_1SEC / HZ * 4) + { + pWait->fHighRes = true; +# if BITS_PER_LONG < 64 + if ( KTIME_SEC_MAX <= LONG_MAX + && pWait->uNsAbsTimeout >= KTIME_SEC_MAX * RT_NS_1SEC_64 + (RT_NS_1SEC - 1)) + fFlags |= RTSEMWAIT_FLAGS_INDEFINITE; + else +# endif + pWait->u.KtTimeout = ns_to_ktime(pWait->uNsAbsTimeout); + } + else +#endif + { + uint64_t cJiffies = ASMMultU64ByU32DivByU32(pWait->cNsRelTimeout, HZ, RT_NS_1SEC); + if (cJiffies >= MAX_JIFFY_OFFSET) + fFlags |= RTSEMWAIT_FLAGS_INDEFINITE; + else + { + pWait->u.lTimeout = (long)cJiffies; + pWait->fHighRes = false; + } + } + } + + if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE) + { + pWait->fIndefinite = true; + pWait->fHighRes = false; + pWait->uNsAbsTimeout = UINT64_MAX; + pWait->cNsRelTimeout = UINT64_MAX; + pWait->u.lTimeout = LONG_MAX; + } + + pWait->fTimedOut = false; + + /* + * Initialize the wait queue related bits. + */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 39) + init_wait((&pWait->WaitQE)); +#else + RT_ZERO(pWait->WaitQE); + init_waitqueue_entry((&pWait->WaitQE), current); +#endif + pWait->pWaitQueue = pWaitQueue; + pWait->iWaitState = fFlags & RTSEMWAIT_FLAGS_INTERRUPTIBLE + ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE; + + return VINF_SUCCESS; +} + + +/** + * Prepares the next wait. + * + * This must be called before rtR0SemLnxWaitDoIt, and the caller should check + * the exit conditions in-between the two calls. + * + * @param pWait The wait structure. + */ +DECLINLINE(void) rtR0SemLnxWaitPrepare(PRTR0SEMLNXWAIT pWait) +{ + /* Make everything thru schedule*() atomic scheduling wise. (Is this correct?) */ + prepare_to_wait(pWait->pWaitQueue, &pWait->WaitQE, pWait->iWaitState); +} + + +/** + * Do the actual wait. + * + * @param pWait The wait structure. + */ +DECLINLINE(void) rtR0SemLnxWaitDoIt(PRTR0SEMLNXWAIT pWait) +{ + if (pWait->fIndefinite) + schedule(); +#ifdef IPRT_LINUX_HAS_HRTIMER + else if (pWait->fHighRes) + { + int rc = schedule_hrtimeout_range(&pWait->u.KtTimeout, HRTIMER_MODE_ABS, RTR0SEMLNXWAIT_RESOLUTION); + if (!rc) + pWait->fTimedOut = true; + } +#endif + else + { + pWait->u.lTimeout = schedule_timeout(pWait->u.lTimeout); + if (pWait->u.lTimeout <= 0) + pWait->fTimedOut = true; + } + after_wait((&pWait->WaitQE)); +} + + +/** + * Checks if a linux wait was interrupted. + * + * @returns true / false + * @param pWait The wait structure. + * @remarks This shall be called before the first rtR0SemLnxWaitDoIt(). + */ +DECLINLINE(bool) rtR0SemLnxWaitWasInterrupted(PRTR0SEMLNXWAIT pWait) +{ + return pWait->iWaitState == TASK_INTERRUPTIBLE + && signal_pending(current); +} + + +/** + * Checks if a linux wait has timed out. + * + * @returns true / false + * @param pWait The wait structure. + */ +DECLINLINE(bool) rtR0SemLnxWaitHasTimedOut(PRTR0SEMLNXWAIT pWait) +{ + return pWait->fTimedOut; +} + + +/** + * Deletes a linux wait. + * + * @param pWait The wait structure. + */ +DECLINLINE(void) rtR0SemLnxWaitDelete(PRTR0SEMLNXWAIT pWait) +{ + finish_wait(pWait->pWaitQueue, &pWait->WaitQE); +} + + +/** + * Gets the max resolution of the timeout machinery. + * + * @returns Resolution specified in nanoseconds. + */ +DECLINLINE(uint32_t) rtR0SemLnxWaitGetResolution(void) +{ +#ifdef IPRT_LINUX_HAS_HRTIMER + return RTR0SEMLNXWAIT_RESOLUTION; +#else + return RT_NS_1SEC / HZ; /* ns */ +#endif +} + +#endif /* !IPRT_INCLUDED_SRC_r0drv_linux_waitqueue_r0drv_linux_h */ + |