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Diffstat (limited to '')
| -rw-r--r-- | src/VBox/Runtime/r0drv/linux/semmutex-r0drv-linux.c | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/src/VBox/Runtime/r0drv/linux/semmutex-r0drv-linux.c b/src/VBox/Runtime/r0drv/linux/semmutex-r0drv-linux.c new file mode 100644 index 00000000..5a0a0ef5 --- /dev/null +++ b/src/VBox/Runtime/r0drv/linux/semmutex-r0drv-linux.c @@ -0,0 +1,421 @@ +/* $Id: semmutex-r0drv-linux.c $ */ +/** @file + * IPRT - Mutex Semaphores, Ring-0 Driver, Linux. + */ + +/* + * 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. + */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#define RTSEMMUTEX_WITHOUT_REMAPPING +#include "the-linux-kernel.h" +#include "internal/iprt.h" +#include <iprt/semaphore.h> + +#include <iprt/assert.h> +#include <iprt/asm.h> +#include <iprt/mem.h> +#include <iprt/err.h> +#include <iprt/list.h> + +#include "internal/magics.h" + + +/********************************************************************************************************************************* +* Structures and Typedefs * +*********************************************************************************************************************************/ +typedef struct RTSEMMUTEXLNXWAITER +{ + /** The list entry. */ + RTLISTNODE ListEntry; + /** The waiting task. */ + struct task_struct *pTask; + /** Why did we wake up? */ + enum + { + /** Wakeup to take the semaphore. */ + RTSEMMUTEXLNXWAITER_WAKEUP, + /** Mutex is being destroyed. */ + RTSEMMUTEXLNXWAITER_DESTROYED, + /** Some other reason. */ + RTSEMMUTEXLNXWAITER_OTHER + } volatile enmReason; +} RTSEMMUTEXLNXWAITER, *PRTSEMMUTEXLNXWAITER; + +/** + * Wrapper for the linux semaphore structure. + */ +typedef struct RTSEMMUTEXINTERNAL +{ + /** Magic value (RTSEMMUTEX_MAGIC). */ + uint32_t u32Magic; + /** The number of recursions. */ + uint32_t cRecursions; + /** The list of waiting threads. */ + RTLISTANCHOR WaiterList; + /** The current owner, NULL if none. */ + struct task_struct *pOwnerTask; + /** The number of references to this piece of memory. This is used to + * prevent it from being kicked from underneath us while waiting. */ + uint32_t volatile cRefs; + /** The spinlock protecting the members and falling asleep. */ + spinlock_t Spinlock; +} RTSEMMUTEXINTERNAL, *PRTSEMMUTEXINTERNAL; + + +RTDECL(int) RTSemMutexCreate(PRTSEMMUTEX phMtx) +{ + int rc = VINF_SUCCESS; + IPRT_LINUX_SAVE_EFL_AC(); + + /* + * Allocate. + */ + PRTSEMMUTEXINTERNAL pThis; + pThis = (PRTSEMMUTEXINTERNAL)RTMemAlloc(sizeof(*pThis)); + if (pThis) + { + /* + * Initialize. + */ + pThis->u32Magic = RTSEMMUTEX_MAGIC; + pThis->cRecursions = 0; + pThis->pOwnerTask = NULL; + pThis->cRefs = 1; + RTListInit(&pThis->WaiterList); + spin_lock_init(&pThis->Spinlock); + + *phMtx = pThis; + } + else + rc = VERR_NO_MEMORY; + + IPRT_LINUX_RESTORE_EFL_AC(); + return rc; +} +RT_EXPORT_SYMBOL(RTSemMutexCreate); + + +RTDECL(int) RTSemMutexDestroy(RTSEMMUTEX hMtx) +{ + PRTSEMMUTEXINTERNAL pThis = hMtx; + PRTSEMMUTEXLNXWAITER pCur; + unsigned long fSavedIrq; + + /* + * Validate. + */ + if (pThis == NIL_RTSEMMUTEX) + return VINF_SUCCESS; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE); + + /* + * Kill it, kick waiters and release it. + */ + AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, RTSEMMUTEX_MAGIC_DEAD, RTSEMMUTEX_MAGIC), VERR_INVALID_HANDLE); + + IPRT_LINUX_SAVE_EFL_AC(); + + spin_lock_irqsave(&pThis->Spinlock, fSavedIrq); + RTListForEach(&pThis->WaiterList, pCur, RTSEMMUTEXLNXWAITER, ListEntry) + { + pCur->enmReason = RTSEMMUTEXLNXWAITER_DESTROYED; + wake_up_process(pCur->pTask); + } + + if (ASMAtomicDecU32(&pThis->cRefs) != 0) + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + else + { + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + RTMemFree(pThis); + } + + IPRT_LINUX_RESTORE_EFL_AC(); + + return VINF_SUCCESS; +} +RT_EXPORT_SYMBOL(RTSemMutexDestroy); + + +/** + * Worker for rtSemMutexLinuxRequest that handles the case where we go to sleep. + * + * @returns VINF_SUCCESS, VERR_INTERRUPTED, VERR_TIMEOUT or VERR_SEM_DESTROYED. + * Returns without owning the spinlock. + * @param pThis The mutex instance. + * @param cMillies The timeout. + * @param fInterruptible The wait type. + * @param fSavedIrq The saved IRQ flags. + */ +static int rtSemMutexLinuxRequestSleep(PRTSEMMUTEXINTERNAL pThis, RTMSINTERVAL cMillies, + bool fInterruptible, unsigned long fSavedIrq) +{ + struct task_struct *pSelf = current; + int rc = VERR_TIMEOUT; + long lTimeout = cMillies == RT_INDEFINITE_WAIT ? MAX_SCHEDULE_TIMEOUT : msecs_to_jiffies(cMillies); + RTSEMMUTEXLNXWAITER Waiter; + + IPRT_DEBUG_SEMS_STATE(pThis, 'm'); + + /* + * Grab a reference to the mutex and add ourselves to the waiter list. + */ + ASMAtomicIncU32(&pThis->cRefs); + + Waiter.pTask = pSelf; + Waiter.enmReason = RTSEMMUTEXLNXWAITER_OTHER; + RTListAppend(&pThis->WaiterList, &Waiter.ListEntry); + + /* + * Do the waiting. + */ + for (;;) + { + /* Check signal and timeout conditions. */ + if ( fInterruptible + && signal_pending(pSelf)) + { + rc = VERR_INTERRUPTED; + break; + } + + if (!lTimeout) + break; + + /* Go to sleep. */ + set_current_state(fInterruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); + spin_unlock_irq(&pThis->Spinlock); + + lTimeout = schedule_timeout(lTimeout); + + spin_lock_irq(&pThis->Spinlock); + set_current_state(TASK_RUNNING); + + /* Did someone wake us up? */ + if (Waiter.enmReason == RTSEMMUTEXLNXWAITER_WAKEUP) + { + Assert(pThis->cRecursions == 0); + pThis->cRecursions = 1; + pThis->pOwnerTask = pSelf; + rc = VINF_SUCCESS; + break; + } + + /* Is the mutex being destroyed? */ + if (RT_UNLIKELY( Waiter.enmReason == RTSEMMUTEXLNXWAITER_DESTROYED + || pThis->u32Magic != RTSEMMUTEX_MAGIC)) + { + rc = VERR_SEM_DESTROYED; + break; + } + } + + /* + * Unlink ourself from the waiter list, dereference the mutex and exit the + * lock. We might have to free the mutex if it was the destroyed. + */ + RTListNodeRemove(&Waiter.ListEntry); + IPRT_DEBUG_SEMS_STATE_RC(pThis, 'M', rc); + + if (RT_LIKELY(ASMAtomicDecU32(&pThis->cRefs) != 0)) + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + else + { + Assert(RT_FAILURE_NP(rc)); + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + RTMemFree(pThis); + } + return rc; +} + + +/** + * Internal worker. + */ +DECLINLINE(int) rtSemMutexLinuxRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, bool fInterruptible) +{ + PRTSEMMUTEXINTERNAL pThis = hMutexSem; + struct task_struct *pSelf = current; + unsigned long fSavedIrq; + int rc; + IPRT_LINUX_SAVE_EFL_AC(); + + /* + * Validate. + */ + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE); + Assert(pThis->cRefs >= 1); + + /* + * Lock it and check if it's a recursion. + */ + spin_lock_irqsave(&pThis->Spinlock, fSavedIrq); + if (pThis->pOwnerTask == pSelf) + { + pThis->cRecursions++; + Assert(pThis->cRecursions > 1); + Assert(pThis->cRecursions < 256); + rc = VINF_SUCCESS; + } + /* + * Not a recursion, maybe it's not owned by anyone then? + */ + else if ( pThis->pOwnerTask == NULL + && RTListIsEmpty(&pThis->WaiterList)) + { + Assert(pThis->cRecursions == 0); + pThis->cRecursions = 1; + pThis->pOwnerTask = pSelf; + rc = VINF_SUCCESS; + } + /* + * Was it a polling call? + */ + else if (cMillies == 0) + rc = VERR_TIMEOUT; + /* + * No, so go to sleep. + */ + else + { + rc = rtSemMutexLinuxRequestSleep(pThis, cMillies, fInterruptible, fSavedIrq); + IPRT_LINUX_RESTORE_EFL_ONLY_AC(); + return rc; + } + + IPRT_DEBUG_SEMS_STATE_RC(pThis, 'M', rc); + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + IPRT_LINUX_RESTORE_EFL_ONLY_AC(); + return rc; +} + + +RTDECL(int) RTSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies) +{ + return rtSemMutexLinuxRequest(hMutexSem, cMillies, false /*fInterruptible*/); +} +RT_EXPORT_SYMBOL(RTSemMutexRequest); + + +RTDECL(int) RTSemMutexRequestDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL) +{ + RT_NOREF_PV(uId); RT_SRC_POS_NOREF(); + return RTSemMutexRequest(hMutexSem, cMillies); +} +RT_EXPORT_SYMBOL(RTSemMutexRequestDebug); + + +RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies) +{ + return rtSemMutexLinuxRequest(hMutexSem, cMillies, true /*fInterruptible*/); +} +RT_EXPORT_SYMBOL(RTSemMutexRequestNoResume); + + +RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL) +{ + RT_NOREF_PV(uId); RT_SRC_POS_NOREF(); + return RTSemMutexRequestNoResume(hMutexSem, cMillies); +} +RT_EXPORT_SYMBOL(RTSemMutexRequestNoResumeDebug); + + +RTDECL(int) RTSemMutexRelease(RTSEMMUTEX hMtx) +{ + PRTSEMMUTEXINTERNAL pThis = hMtx; + struct task_struct *pSelf = current; + unsigned long fSavedIrq; + int rc; + IPRT_LINUX_SAVE_EFL_AC(); + + /* + * Validate. + */ + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE); + Assert(pThis->cRefs >= 1); + + /* + * Take the lock and release one recursion. + */ + spin_lock_irqsave(&pThis->Spinlock, fSavedIrq); + if (pThis->pOwnerTask == pSelf) + { + Assert(pThis->cRecursions > 0); + if (--pThis->cRecursions == 0) + { + pThis->pOwnerTask = NULL; + + /* anyone to wake up? */ + if (!RTListIsEmpty(&pThis->WaiterList)) + { + PRTSEMMUTEXLNXWAITER pWaiter = RTListGetFirst(&pThis->WaiterList, RTSEMMUTEXLNXWAITER, ListEntry); + pWaiter->enmReason = RTSEMMUTEXLNXWAITER_WAKEUP; + wake_up_process(pWaiter->pTask); + } + IPRT_DEBUG_SEMS_STATE(pThis, 'u'); + } + rc = VINF_SUCCESS; + } + else + rc = VERR_NOT_OWNER; + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + + AssertRC(rc); + IPRT_LINUX_RESTORE_EFL_AC(); + return rc; +} +RT_EXPORT_SYMBOL(RTSemMutexRelease); + + +RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem) +{ + PRTSEMMUTEXINTERNAL pThis = hMutexSem; + unsigned long fSavedIrq; + bool fOwned; + IPRT_LINUX_SAVE_EFL_AC(); + + /* + * Validate. + */ + AssertPtrReturn(pThis, false); + AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), false); + Assert(pThis->cRefs >= 1); + + /* + * Take the lock and release one recursion. + */ + spin_lock_irqsave(&pThis->Spinlock, fSavedIrq); + fOwned = pThis->pOwnerTask != NULL; + spin_unlock_irqrestore(&pThis->Spinlock, fSavedIrq); + + IPRT_LINUX_RESTORE_EFL_AC(); + return fOwned; + +} +RT_EXPORT_SYMBOL(RTSemMutexIsOwned); + |