--- /dev/null
+/* $Id: semevent-r0drv-linux.c $ */
+/** @file
+ * IPRT - Single Release Event Semaphores, Ring-0 Driver, Linux.
+ */
+
+/*
+ * Copyright (C) 2006-2017 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 RTSEMEVENT_WITHOUT_REMAPPING
+#include "the-linux-kernel.h"
+#include "internal/iprt.h"
+#include <iprt/semaphore.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+
+#include "waitqueue-r0drv-linux.h"
+#include "internal/magics.h"
+
+
+/*********************************************************************************************************************************
+* Structures and Typedefs *
+*********************************************************************************************************************************/
+/**
+ * Linux event semaphore.
+ */
+typedef struct RTSEMEVENTINTERNAL
+{
+ /** Magic value (RTSEMEVENT_MAGIC). */
+ uint32_t volatile u32Magic;
+ /** The object status - !0 when signaled and 0 when reset. */
+ uint32_t volatile fState;
+ /** Reference counter. */
+ uint32_t volatile cRefs;
+ /** The wait queue. */
+ wait_queue_head_t Head;
+} RTSEMEVENTINTERNAL, *PRTSEMEVENTINTERNAL;
+
+
+
+RTDECL(int) RTSemEventCreate(PRTSEMEVENT phEventSem)
+{
+ return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int) RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
+{
+ PRTSEMEVENTINTERNAL pThis;
+ IPRT_LINUX_SAVE_EFL_AC();
+ RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
+
+ AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
+ Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
+
+ pThis = (PRTSEMEVENTINTERNAL)RTMemAlloc(sizeof(*pThis));
+ if (!pThis)
+ return VERR_NO_MEMORY;
+
+ pThis->u32Magic = RTSEMEVENT_MAGIC;
+ pThis->fState = 0;
+ pThis->cRefs = 1;
+ init_waitqueue_head(&pThis->Head);
+
+ *phEventSem = pThis;
+ IPRT_LINUX_RESTORE_EFL_AC();
+ return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTSemEventCreate);
+
+
+/**
+ * Retains a reference to the event semaphore.
+ *
+ * @param pThis The event semaphore.
+ */
+DECLINLINE(void) rtR0SemEventLnxRetain(PRTSEMEVENTINTERNAL pThis)
+{
+ uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+ Assert(cRefs < 100000); NOREF(cRefs);
+}
+
+
+/**
+ * Releases a reference to the event semaphore.
+ *
+ * @param pThis The event semaphore.
+ */
+DECLINLINE(void) rtR0SemEventLnxRelease(PRTSEMEVENTINTERNAL pThis)
+{
+ if (RT_UNLIKELY(ASMAtomicDecU32(&pThis->cRefs) == 0))
+ RTMemFree(pThis);
+}
+
+
+RTDECL(int) RTSemEventDestroy(RTSEMEVENT hEventSem)
+{
+ IPRT_LINUX_SAVE_EFL_AC();
+
+ /*
+ * Validate input.
+ */
+ PRTSEMEVENTINTERNAL pThis = hEventSem;
+ if (pThis == NIL_RTSEMEVENT)
+ return VINF_SUCCESS;
+ AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);
+ Assert(pThis->cRefs > 0);
+
+ /*
+ * Invalidate it and signal the object just in case.
+ */
+ ASMAtomicWriteU32(&pThis->u32Magic, ~RTSEMEVENT_MAGIC);
+ ASMAtomicWriteU32(&pThis->fState, 0);
+ Assert(!waitqueue_active(&pThis->Head));
+ wake_up_all(&pThis->Head);
+ rtR0SemEventLnxRelease(pThis);
+
+ IPRT_LINUX_RESTORE_EFL_AC();
+ return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTSemEventDestroy);
+
+
+RTDECL(int) RTSemEventSignal(RTSEMEVENT hEventSem)
+{
+ IPRT_LINUX_SAVE_EFL_AC();
+
+ /*
+ * Validate input.
+ */
+ PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem;
+ AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+ AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);
+ rtR0SemEventLnxRetain(pThis);
+
+ /*
+ * Signal the event object.
+ */
+ ASMAtomicWriteU32(&pThis->fState, 1);
+ wake_up(&pThis->Head);
+
+ rtR0SemEventLnxRelease(pThis);
+ IPRT_LINUX_RESTORE_EFL_AC();
+ return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTSemEventSignal);
+
+
+/**
+ * Worker for RTSemEventWaitEx and RTSemEventWaitExDebug.
+ *
+ * @returns VBox status code.
+ * @param pThis The event semaphore.
+ * @param fFlags See RTSemEventWaitEx.
+ * @param uTimeout See RTSemEventWaitEx.
+ * @param pSrcPos The source code position of the wait.
+ */
+static int rtR0SemEventLnxWait(PRTSEMEVENTINTERNAL pThis, uint32_t fFlags, uint64_t uTimeout,
+ PCRTLOCKVALSRCPOS pSrcPos)
+{
+ int rc;
+ RT_NOREF_PV(pSrcPos);
+
+ /*
+ * Validate the input.
+ */
+ AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+ AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
+ AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
+ rtR0SemEventLnxRetain(pThis);
+
+ /*
+ * Try grab the event without setting up the wait.
+ */
+ if ( 1 /** @todo check if there are someone waiting already - waitqueue_active, but then what do we do below? */
+ && ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
+ rc = VINF_SUCCESS;
+ else
+ {
+ /*
+ * We have to wait.
+ */
+ IPRT_LINUX_SAVE_EFL_AC();
+ RTR0SEMLNXWAIT Wait;
+ rc = rtR0SemLnxWaitInit(&Wait, fFlags, uTimeout, &pThis->Head);
+ if (RT_SUCCESS(rc))
+ {
+ IPRT_DEBUG_SEMS_STATE(pThis, 'E');
+ for (;;)
+ {
+ /* The destruction test. */
+ if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
+ rc = VERR_SEM_DESTROYED;
+ else
+ {
+ rtR0SemLnxWaitPrepare(&Wait);
+
+ /* Check the exit conditions. */
+ if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
+ rc = VERR_SEM_DESTROYED;
+ else if (ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
+ rc = VINF_SUCCESS;
+ else if (rtR0SemLnxWaitHasTimedOut(&Wait))
+ rc = VERR_TIMEOUT;
+ else if (rtR0SemLnxWaitWasInterrupted(&Wait))
+ rc = VERR_INTERRUPTED;
+ else
+ {
+ /* Do the wait and then recheck the conditions. */
+ rtR0SemLnxWaitDoIt(&Wait);
+ continue;
+ }
+ }
+ break;
+ }
+
+ rtR0SemLnxWaitDelete(&Wait);
+ IPRT_DEBUG_SEMS_STATE_RC(pThis, 'E', rc);
+ }
+ IPRT_LINUX_RESTORE_EFL_AC();
+ }
+
+ rtR0SemEventLnxRelease(pThis);
+ return rc;
+}
+
+
+RTDECL(int) RTSemEventWaitEx(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout)
+{
+#ifndef RTSEMEVENT_STRICT
+ return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, NULL);
+#else
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+ return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, &SrcPos);
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemEventWaitEx);
+
+
+RTDECL(int) RTSemEventWaitExDebug(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout,
+ RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+ return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, &SrcPos);
+}
+RT_EXPORT_SYMBOL(RTSemEventWaitExDebug);
+
+
+RTDECL(uint32_t) RTSemEventGetResolution(void)
+{
+ return rtR0SemLnxWaitGetResolution();
+}
+RT_EXPORT_SYMBOL(RTSemEventGetResolution);
+
projects / mirror_ubuntu-bionic-kernel.git / blobdiff