| 1 | /* $Id: mpnotification-r0drv.c 98103 2023-01-17 14:15:46Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - Multiprocessor, Ring-0 Driver, Event Notifications.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2008-2023 Oracle and/or its affiliates.
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| 8 | *
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| 9 | * This file is part of VirtualBox base platform packages, as
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| 10 | * available from https://www.virtualbox.org.
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| 11 | *
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| 12 | * This program is free software; you can redistribute it and/or
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| 13 | * modify it under the terms of the GNU General Public License
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| 14 | * as published by the Free Software Foundation, in version 3 of the
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| 15 | * License.
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| 16 | *
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| 17 | * This program is distributed in the hope that it will be useful, but
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| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | * General Public License for more details.
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| 21 | *
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| 22 | * You should have received a copy of the GNU General Public License
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| 23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | *
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| 25 | * The contents of this file may alternatively be used under the terms
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| 26 | * of the Common Development and Distribution License Version 1.0
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| 27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | * in the VirtualBox distribution, in which case the provisions of the
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| 29 | * CDDL are applicable instead of those of the GPL.
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| 30 | *
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| 31 | * You may elect to license modified versions of this file under the
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| 32 | * terms and conditions of either the GPL or the CDDL or both.
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| 33 | *
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| 34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 35 | */
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| 36 |
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| 37 |
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| 38 | /*********************************************************************************************************************************
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| 39 | * Header Files *
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| 40 | *********************************************************************************************************************************/
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| 41 | #include <iprt/mp.h>
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| 42 | #include "internal/iprt.h"
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| 43 |
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| 44 | #include <iprt/asm.h>
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| 45 | #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
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| 46 | # include <iprt/asm-amd64-x86.h>
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| 47 | #endif
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| 48 | #include <iprt/assert.h>
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| 49 | #include <iprt/err.h>
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| 50 | #include <iprt/mem.h>
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| 51 | #include <iprt/spinlock.h>
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| 52 | #include <iprt/string.h>
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| 53 | #include <iprt/thread.h>
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| 54 | #include "r0drv/mp-r0drv.h"
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| 55 |
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| 56 |
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| 57 | /*********************************************************************************************************************************
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| 58 | * Structures and Typedefs *
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| 59 | *********************************************************************************************************************************/
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| 60 | /**
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| 61 | * Notification registration record tracking
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| 62 | * RTMpRegisterNotification() calls.
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| 63 | */
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| 64 | typedef struct RTMPNOTIFYREG
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| 65 | {
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| 66 | /** Pointer to the next record. */
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| 67 | struct RTMPNOTIFYREG * volatile pNext;
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| 68 | /** The callback. */
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| 69 | PFNRTMPNOTIFICATION pfnCallback;
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| 70 | /** The user argument. */
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| 71 | void *pvUser;
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| 72 | /** Bit mask indicating whether we've done this callback or not. */
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| 73 | uint8_t bmDone[sizeof(void *)];
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| 74 | } RTMPNOTIFYREG;
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| 75 | /** Pointer to a registration record. */
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| 76 | typedef RTMPNOTIFYREG *PRTMPNOTIFYREG;
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| 77 |
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| 78 |
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| 79 | /*********************************************************************************************************************************
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| 80 | * Global Variables *
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| 81 | *********************************************************************************************************************************/
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| 82 | /** The spinlock protecting the list. */
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| 83 | static RTSPINLOCK volatile g_hRTMpNotifySpinLock = NIL_RTSPINLOCK;
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| 84 | /** List of callbacks, in registration order. */
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| 85 | static PRTMPNOTIFYREG volatile g_pRTMpCallbackHead = NULL;
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| 86 | /** The current done bit. */
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| 87 | static uint32_t volatile g_iRTMpDoneBit;
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| 88 | /** The list generation.
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| 89 | * This is increased whenever the list has been modified. The callback routine
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| 90 | * make use of this to avoid having restart at the list head after each callback. */
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| 91 | static uint32_t volatile g_iRTMpGeneration;
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| 92 |
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| 93 |
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| 94 |
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| 95 |
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| 96 | /**
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| 97 | * This is called by the native code.
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| 98 | *
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| 99 | * @param idCpu The CPU id the event applies to.
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| 100 | * @param enmEvent The event.
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| 101 | */
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| 102 | DECLHIDDEN(void) rtMpNotificationDoCallbacks(RTMPEVENT enmEvent, RTCPUID idCpu)
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| 103 | {
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| 104 | PRTMPNOTIFYREG pCur;
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| 105 | RTSPINLOCK hSpinlock;
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| 106 |
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| 107 | /*
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| 108 | * This is a little bit tricky as we cannot be holding the spinlock
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| 109 | * while calling the callback. This means that the list might change
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| 110 | * while we're walking it, and that multiple events might be running
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| 111 | * concurrently (depending on the OS).
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| 112 | *
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| 113 | * So, the first measure is to employ a 32-bitmask for each
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| 114 | * record where we'll use a bit that rotates for each call to
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| 115 | * this function to indicate which records that has been
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| 116 | * processed. This will take care of both changes to the list
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| 117 | * and a reasonable amount of concurrent events.
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| 118 | *
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| 119 | * In order to avoid having to restart the list walks for every
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| 120 | * callback we make, we'll make use a list generation number that is
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| 121 | * incremented everytime the list is changed. So, if it remains
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| 122 | * unchanged over a callback we can safely continue the iteration.
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| 123 | */
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| 124 | uint32_t iDone = ASMAtomicIncU32(&g_iRTMpDoneBit);
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| 125 | iDone %= RT_SIZEOFMEMB(RTMPNOTIFYREG, bmDone) * 8;
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| 126 |
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| 127 | hSpinlock = g_hRTMpNotifySpinLock;
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| 128 | if (hSpinlock == NIL_RTSPINLOCK)
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| 129 | return;
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| 130 | RTSpinlockAcquire(hSpinlock);
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| 131 |
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| 132 | /* Clear the bit. */
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| 133 | for (pCur = g_pRTMpCallbackHead; pCur; pCur = pCur->pNext)
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| 134 | ASMAtomicBitClear(&pCur->bmDone[0], iDone);
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| 135 |
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| 136 | /* Iterate the records and perform the callbacks. */
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| 137 | do
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| 138 | {
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| 139 | uint32_t const iGeneration = ASMAtomicUoReadU32(&g_iRTMpGeneration);
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| 140 |
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| 141 | pCur = g_pRTMpCallbackHead;
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| 142 | while (pCur)
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| 143 | {
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| 144 | if (!ASMAtomicBitTestAndSet(&pCur->bmDone[0], iDone))
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| 145 | {
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| 146 | PFNRTMPNOTIFICATION pfnCallback = pCur->pfnCallback;
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| 147 | void *pvUser = pCur->pvUser;
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| 148 | pCur = pCur->pNext;
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| 149 | RTSpinlockRelease(g_hRTMpNotifySpinLock);
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| 150 |
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| 151 | pfnCallback(enmEvent, idCpu, pvUser);
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| 152 |
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| 153 | /* carefully require the lock here, see RTR0MpNotificationTerm(). */
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| 154 | hSpinlock = g_hRTMpNotifySpinLock;
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| 155 | if (hSpinlock == NIL_RTSPINLOCK)
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| 156 | return;
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| 157 | RTSpinlockAcquire(hSpinlock);
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| 158 | if (ASMAtomicUoReadU32(&g_iRTMpGeneration) != iGeneration)
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| 159 | break;
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| 160 | }
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| 161 | else
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| 162 | pCur = pCur->pNext;
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| 163 | }
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| 164 | } while (pCur);
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| 165 |
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| 166 | RTSpinlockRelease(hSpinlock);
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| 167 | }
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| 168 |
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| 169 |
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| 170 |
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| 171 | RTDECL(int) RTMpNotificationRegister(PFNRTMPNOTIFICATION pfnCallback, void *pvUser)
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| 172 | {
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| 173 | PRTMPNOTIFYREG pCur;
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| 174 | PRTMPNOTIFYREG pNew;
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| 175 |
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| 176 | /*
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| 177 | * Validation.
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| 178 | */
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| 179 | AssertPtrReturn(pfnCallback, VERR_INVALID_POINTER);
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| 180 | AssertReturn(g_hRTMpNotifySpinLock != NIL_RTSPINLOCK, VERR_WRONG_ORDER);
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| 181 | RT_ASSERT_PREEMPTIBLE();
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| 182 |
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| 183 | RTSpinlockAcquire(g_hRTMpNotifySpinLock);
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| 184 | for (pCur = g_pRTMpCallbackHead; pCur; pCur = pCur->pNext)
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| 185 | if ( pCur->pvUser == pvUser
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| 186 | && pCur->pfnCallback == pfnCallback)
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| 187 | break;
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| 188 | RTSpinlockRelease(g_hRTMpNotifySpinLock);
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| 189 | AssertMsgReturn(!pCur, ("pCur=%p pfnCallback=%p pvUser=%p\n", pCur, pfnCallback, pvUser), VERR_ALREADY_EXISTS);
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| 190 |
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| 191 | /*
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| 192 | * Allocate a new record and attempt to insert it.
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| 193 | */
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| 194 | pNew = (PRTMPNOTIFYREG)RTMemAlloc(sizeof(*pNew));
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| 195 | if (!pNew)
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| 196 | return VERR_NO_MEMORY;
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| 197 |
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| 198 | pNew->pNext = NULL;
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| 199 | pNew->pfnCallback = pfnCallback;
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| 200 | pNew->pvUser = pvUser;
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| 201 | memset(&pNew->bmDone[0], 0xff, sizeof(pNew->bmDone));
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| 202 |
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| 203 | RTSpinlockAcquire(g_hRTMpNotifySpinLock);
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| 204 |
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| 205 | pCur = g_pRTMpCallbackHead;
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| 206 | if (!pCur)
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| 207 | g_pRTMpCallbackHead = pNew;
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| 208 | else
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| 209 | {
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| 210 | for (pCur = g_pRTMpCallbackHead; ; pCur = pCur->pNext)
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| 211 | if ( pCur->pvUser == pvUser
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| 212 | && pCur->pfnCallback == pfnCallback)
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| 213 | break;
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| 214 | else if (!pCur->pNext)
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| 215 | {
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| 216 | pCur->pNext = pNew;
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| 217 | pCur = NULL;
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| 218 | break;
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| 219 | }
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| 220 | }
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| 221 |
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| 222 | ASMAtomicIncU32(&g_iRTMpGeneration);
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| 223 |
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| 224 | RTSpinlockRelease(g_hRTMpNotifySpinLock);
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| 225 |
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| 226 | /* duplicate? */
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| 227 | if (pCur)
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| 228 | {
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| 229 | RTMemFree(pCur);
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| 230 | AssertMsgFailedReturn(("pCur=%p pfnCallback=%p pvUser=%p\n", pCur, pfnCallback, pvUser), VERR_ALREADY_EXISTS);
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| 231 | }
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| 232 |
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| 233 | return VINF_SUCCESS;
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| 234 | }
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| 235 | RT_EXPORT_SYMBOL(RTMpNotificationRegister);
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| 236 |
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| 237 |
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| 238 | RTDECL(int) RTMpNotificationDeregister(PFNRTMPNOTIFICATION pfnCallback, void *pvUser)
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| 239 | {
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| 240 | PRTMPNOTIFYREG pPrev;
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| 241 | PRTMPNOTIFYREG pCur;
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| 242 |
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| 243 | /*
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| 244 | * Validation.
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| 245 | */
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| 246 | AssertPtrReturn(pfnCallback, VERR_INVALID_POINTER);
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| 247 | AssertReturn(g_hRTMpNotifySpinLock != NIL_RTSPINLOCK, VERR_WRONG_ORDER);
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| 248 | RT_ASSERT_INTS_ON();
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| 249 |
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| 250 | /*
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| 251 | * Find and unlink the record from the list.
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| 252 | */
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| 253 | RTSpinlockAcquire(g_hRTMpNotifySpinLock);
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| 254 | pPrev = NULL;
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| 255 | for (pCur = g_pRTMpCallbackHead; pCur; pCur = pCur->pNext)
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| 256 | {
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| 257 | if ( pCur->pvUser == pvUser
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| 258 | && pCur->pfnCallback == pfnCallback)
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| 259 | break;
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| 260 | pPrev = pCur;
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| 261 | }
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| 262 | if (pCur)
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| 263 | {
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| 264 | if (pPrev)
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| 265 | pPrev->pNext = pCur->pNext;
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| 266 | else
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| 267 | g_pRTMpCallbackHead = pCur->pNext;
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| 268 | ASMAtomicIncU32(&g_iRTMpGeneration);
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| 269 | }
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| 270 | RTSpinlockRelease(g_hRTMpNotifySpinLock);
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| 271 |
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| 272 | if (!pCur)
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| 273 | return VERR_NOT_FOUND;
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| 274 |
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| 275 | /*
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| 276 | * Invalidate and free the record.
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| 277 | */
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| 278 | pCur->pNext = NULL;
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| 279 | pCur->pfnCallback = NULL;
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| 280 | RTMemFree(pCur);
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| 281 |
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| 282 | return VINF_SUCCESS;
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| 283 | }
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| 284 | RT_EXPORT_SYMBOL(RTMpNotificationDeregister);
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| 285 |
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| 286 |
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| 287 | DECLHIDDEN(int) rtR0MpNotificationInit(void)
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| 288 | {
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| 289 | int rc = RTSpinlockCreate((PRTSPINLOCK)&g_hRTMpNotifySpinLock, RTSPINLOCK_FLAGS_INTERRUPT_SAFE, "RTR0Mp");
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| 290 | if (RT_SUCCESS(rc))
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| 291 | {
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| 292 | rc = rtR0MpNotificationNativeInit();
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| 293 | if (RT_SUCCESS(rc))
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| 294 | return rc;
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| 295 |
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| 296 | RTSpinlockDestroy(g_hRTMpNotifySpinLock);
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| 297 | g_hRTMpNotifySpinLock = NIL_RTSPINLOCK;
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| 298 | }
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| 299 | return rc;
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| 300 | }
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| 301 |
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| 302 |
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| 303 | DECLHIDDEN(void) rtR0MpNotificationTerm(void)
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| 304 | {
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| 305 | PRTMPNOTIFYREG pHead;
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| 306 | RTSPINLOCK hSpinlock = g_hRTMpNotifySpinLock;
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| 307 | AssertReturnVoid(hSpinlock != NIL_RTSPINLOCK);
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| 308 |
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| 309 | rtR0MpNotificationNativeTerm();
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| 310 |
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| 311 | /* pick up the list and the spinlock. */
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| 312 | RTSpinlockAcquire(hSpinlock);
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| 313 | ASMAtomicWriteHandle(&g_hRTMpNotifySpinLock, NIL_RTSPINLOCK);
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| 314 | pHead = g_pRTMpCallbackHead;
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| 315 | g_pRTMpCallbackHead = NULL;
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| 316 | ASMAtomicIncU32(&g_iRTMpGeneration);
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| 317 | RTSpinlockRelease(hSpinlock);
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| 318 |
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| 319 | /* free the list. */
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| 320 | while (pHead)
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| 321 | {
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| 322 | PRTMPNOTIFYREG pFree = pHead;
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| 323 | pHead = pHead->pNext;
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| 324 |
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| 325 | pFree->pNext = NULL;
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| 326 | pFree->pfnCallback = NULL;
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| 327 | RTMemFree(pFree);
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| 328 | }
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| 329 |
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| 330 | RTSpinlockDestroy(hSpinlock);
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| 331 | }
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| 332 |
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