Current File : //usr/share/virtualbox/src/vboxhost/vboxdrv/r0drv/linux/semeventmulti-r0drv-linux.c
/* $Id: semeventmulti-r0drv-linux.c 155244 2023-01-17 14:15:46Z bird $ */
/** @file
* IPRT - Multiple Release Event Semaphores, Ring-0 Driver, Linux.
*/
/*
* Copyright (C) 2006-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox 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.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#define RTSEMEVENTMULTI_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/err.h>
#include <iprt/mem.h>
#include <iprt/lockvalidator.h>
#include "waitqueue-r0drv-linux.h"
#include "internal/magics.h"
/*********************************************************************************************************************************
* Defined Constants And Macros *
*********************************************************************************************************************************/
/** @name fStateAndGen values
* @{ */
/** The state bit number. */
#define RTSEMEVENTMULTILNX_STATE_BIT 0
/** The state mask. */
#define RTSEMEVENTMULTILNX_STATE_MASK RT_BIT_32(RTSEMEVENTMULTILNX_STATE_BIT)
/** The generation mask. */
#define RTSEMEVENTMULTILNX_GEN_MASK ~RTSEMEVENTMULTILNX_STATE_MASK
/** The generation shift. */
#define RTSEMEVENTMULTILNX_GEN_SHIFT 1
/** The initial variable value. */
#define RTSEMEVENTMULTILNX_STATE_GEN_INIT UINT32_C(0xfffffffc)
/** @} */
/*********************************************************************************************************************************
* Structures and Typedefs *
*********************************************************************************************************************************/
/**
* Linux event semaphore.
*/
typedef struct RTSEMEVENTMULTIINTERNAL
{
/** Magic value (RTSEMEVENTMULTI_MAGIC). */
uint32_t volatile u32Magic;
/** The object state bit and generation counter.
* The generation counter is incremented every time the object is
* signalled. */
uint32_t volatile fStateAndGen;
/** Reference counter. */
uint32_t volatile cRefs;
/** The wait queue. */
wait_queue_head_t Head;
} RTSEMEVENTMULTIINTERNAL, *PRTSEMEVENTMULTIINTERNAL;
RTDECL(int) RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem)
{
return RTSemEventMultiCreateEx(phEventMultiSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
}
RTDECL(int) RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
const char *pszNameFmt, ...)
{
PRTSEMEVENTMULTIINTERNAL pThis;
IPRT_LINUX_SAVE_EFL_AC();
RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
AssertReturn(!(fFlags & ~RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
pThis = (PRTSEMEVENTMULTIINTERNAL)RTMemAlloc(sizeof(*pThis));
if (pThis)
{
pThis->u32Magic = RTSEMEVENTMULTI_MAGIC;
pThis->fStateAndGen = RTSEMEVENTMULTILNX_STATE_GEN_INIT;
pThis->cRefs = 1;
init_waitqueue_head(&pThis->Head);
*phEventMultiSem = pThis;
IPRT_LINUX_RESTORE_EFL_AC();
return VINF_SUCCESS;
}
IPRT_LINUX_RESTORE_EFL_AC();
return VERR_NO_MEMORY;
}
RT_EXPORT_SYMBOL(RTSemEventMultiCreate);
/**
* Retain a reference to the semaphore.
*
* @param pThis The semaphore.
*/
DECLINLINE(void) rtR0SemEventMultiLnxRetain(PRTSEMEVENTMULTIINTERNAL pThis)
{
uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
NOREF(cRefs);
Assert(cRefs && cRefs < 100000);
}
/**
* Release a reference, destroy the thing if necessary.
*
* @param pThis The semaphore.
*/
DECLINLINE(void) rtR0SemEventMultiLnxRelease(PRTSEMEVENTMULTIINTERNAL pThis)
{
if (RT_UNLIKELY(ASMAtomicDecU32(&pThis->cRefs) == 0))
{
Assert(pThis->u32Magic != RTSEMEVENTMULTI_MAGIC);
RTMemFree(pThis);
}
}
RTDECL(int) RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem)
{
IPRT_LINUX_SAVE_EFL_AC();
/*
* Validate input.
*/
PRTSEMEVENTMULTIINTERNAL pThis = (PRTSEMEVENTMULTIINTERNAL)hEventMultiSem;
if (pThis == NIL_RTSEMEVENTMULTI)
return VINF_SUCCESS;
AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
AssertMsgReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
Assert(pThis->cRefs > 0);
/*
* Invalidate it and signal the object just in case.
*/
ASMAtomicWriteU32(&pThis->u32Magic, ~RTSEMEVENTMULTI_MAGIC);
ASMAtomicAndU32(&pThis->fStateAndGen, RTSEMEVENTMULTILNX_GEN_MASK);
Assert(!waitqueue_active(&pThis->Head));
wake_up_all(&pThis->Head);
rtR0SemEventMultiLnxRelease(pThis);
IPRT_LINUX_RESTORE_EFL_AC();
return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemEventMultiDestroy);
RTDECL(int) RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem)
{
IPRT_LINUX_SAVE_EFL_AC();
uint32_t fNew;
uint32_t fOld;
/*
* Validate input.
*/
PRTSEMEVENTMULTIINTERNAL pThis = (PRTSEMEVENTMULTIINTERNAL)hEventMultiSem;
if (!pThis)
return VERR_INVALID_PARAMETER;
AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
AssertMsgReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
rtR0SemEventMultiLnxRetain(pThis);
/*
* Signal the event object. The cause of the paranoia here is racing to try
* deal with racing RTSemEventMultiSignal calls (should probably be
* forbidden, but it's relatively easy to handle).
*/
do
{
fNew = fOld = ASMAtomicUoReadU32(&pThis->fStateAndGen);
fNew += 1 << RTSEMEVENTMULTILNX_GEN_SHIFT;
fNew |= RTSEMEVENTMULTILNX_STATE_MASK;
}
while (!ASMAtomicCmpXchgU32(&pThis->fStateAndGen, fNew, fOld));
wake_up_all(&pThis->Head);
rtR0SemEventMultiLnxRelease(pThis);
IPRT_LINUX_RESTORE_EFL_AC();
return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemEventMultiSignal);
RTDECL(int) RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
{
/*
* Validate input.
*/
PRTSEMEVENTMULTIINTERNAL pThis = (PRTSEMEVENTMULTIINTERNAL)hEventMultiSem;
if (!pThis)
return VERR_INVALID_PARAMETER;
AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
AssertMsgReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
rtR0SemEventMultiLnxRetain(pThis);
/*
* Reset it.
*/
ASMAtomicAndU32(&pThis->fStateAndGen, ~RTSEMEVENTMULTILNX_STATE_MASK);
rtR0SemEventMultiLnxRelease(pThis);
return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemEventMultiReset);
/**
* Worker for RTSemEventMultiWaitEx and RTSemEventMultiWaitExDebug.
*
* @returns VBox status code.
* @param pThis The event semaphore.
* @param fFlags See RTSemEventMultiWaitEx.
* @param uTimeout See RTSemEventMultiWaitEx.
* @param pSrcPos The source code position of the wait.
*/
static int rtR0SemEventMultiLnxWait(PRTSEMEVENTMULTIINTERNAL pThis, uint32_t fFlags, uint64_t uTimeout,
PCRTLOCKVALSRCPOS pSrcPos)
{
uint32_t fOrgStateAndGen;
int rc;
RT_NOREF_PV(pSrcPos);
/*
* Validate the input.
*/
AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
AssertMsgReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
rtR0SemEventMultiLnxRetain(pThis);
/*
* Is the event already signalled or do we have to wait?
*/
fOrgStateAndGen = ASMAtomicUoReadU32(&pThis->fStateAndGen);
if (fOrgStateAndGen & RTSEMEVENTMULTILNX_STATE_MASK)
rc = VINF_SUCCESS;
else
{
/*
* We have to wait.
*/
RTR0SEMLNXWAIT Wait;
IPRT_LINUX_SAVE_EFL_AC();
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 != RTSEMEVENTMULTI_MAGIC))
rc = VERR_SEM_DESTROYED;
else
{
rtR0SemLnxWaitPrepare(&Wait);
/* Check the exit conditions. */
if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENTMULTI_MAGIC))
rc = VERR_SEM_DESTROYED;
else if (ASMAtomicUoReadU32(&pThis->fStateAndGen) != fOrgStateAndGen)
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();
}
rtR0SemEventMultiLnxRelease(pThis);
return rc;
}
RTDECL(int) RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout)
{
#ifndef RTSEMEVENT_STRICT
return rtR0SemEventMultiLnxWait(hEventMultiSem, fFlags, uTimeout, NULL);
#else
RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
return rtR0SemEventMultiLnxWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
#endif
}
RT_EXPORT_SYMBOL(RTSemEventMultiWaitEx);
RTDECL(int) RTSemEventMultiWaitExDebug(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
RTHCUINTPTR uId, RT_SRC_POS_DECL)
{
RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
return rtR0SemEventMultiLnxWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
}
RT_EXPORT_SYMBOL(RTSemEventMultiWaitExDebug);
RTDECL(uint32_t) RTSemEventMultiGetResolution(void)
{
return rtR0SemLnxWaitGetResolution();
}
RT_EXPORT_SYMBOL(RTSemEventMultiGetResolution);
RTR0DECL(bool) RTSemEventMultiIsSignalSafe(void)
{
return true;
}
RT_EXPORT_SYMBOL(RTSemEventMultiIsSignalSafe);
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