Current File : //usr/src/vboxhost-6.0.14/vboxdrv/r0drv/linux/semevent-r0drv-linux.c
/* $Id: semevent-r0drv-linux.c 127855 2019-01-01 01:45:53Z bird $ */
/** @file
* IPRT - Single Release Event 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 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);
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