reactos/ntoskrnl/ke/process.c

   1 /*
   2  *  ReactOS kernel
   3  *  Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 /* $Id: process.c,v 1.18 2003/12/30 18:52:04 fireball Exp $
  20  *
  21  * PROJECT:         ReactOS kernel
  22  * FILE:            ntoskrnl/ke/process.c
  23  * PURPOSE:         Microkernel process management
  24  * PROGRAMMER:      David Welch (welch@cwcom.net)
  25  * PORTABILITY:     No.
  26  * UPDATE HISTORY:
  27  *                  Created 22/05/98
  28  */
  29
  30 /* INCLUDES *****************************************************************/
  31
  32 #include <ddk/ntddk.h>
  33 #include <internal/ke.h>
  34 #include <internal/mm.h>
  35 #include <internal/ps.h>
  36
  37 #define NDEBUG
  38 #include <internal/debug.h>
  39
  40 /* FUNCTIONS *****************************************************************/
  41
  42 /*
  43  * @implemented
  44  */
  45 VOID STDCALL
  46 KeAttachProcess (PEPROCESS Process)
  47 {
  48    KIRQL oldlvl;
  49    PETHREAD CurrentThread;
  50    PULONG AttachedProcessPageDir;
  51    ULONG PageDir;
  52
  53    DPRINT("KeAttachProcess(Process %x)\n",Process);
  54
  55    CurrentThread = PsGetCurrentThread();
  56
  57    if (CurrentThread->OldProcess != NULL)
  58      {
  59         DbgPrint("Invalid attach (thread is already attached)\n");
  60         KEBUGCHECK(0);
  61      }
  62
  63    KeRaiseIrql(DISPATCH_LEVEL, &oldlvl);
  64
  65    KiSwapApcEnvironment(&CurrentThread->Tcb, &Process->Pcb);
  66
  67    /* The stack of the current process may be located in a page which is
  68       not present in the page directory of the process we're attaching to.
  69       That would lead to a page fault when this function returns. However,
  70       since the processor can't call the page fault handler 'cause it can't
  71       push EIP on the stack, this will show up as a stack fault which will
  72       crash the entire system.
  73       To prevent this, make sure the page directory of the process we're
  74       attaching to is up-to-date. */
  75
  76    AttachedProcessPageDir = ExAllocatePageWithPhysPage(Process->Pcb.DirectoryTableBase);
  77    MmUpdateStackPageDir(AttachedProcessPageDir, &CurrentThread->Tcb);
  78    ExUnmapPage(AttachedProcessPageDir);
  79
  80    CurrentThread->OldProcess = PsGetCurrentProcess();
  81    CurrentThread->ThreadsProcess = Process;
  82    PageDir = Process->Pcb.DirectoryTableBase.u.LowPart;
  83    DPRINT("Switching process context to %x\n",PageDir);
  84 #if defined(__GNUC__)
  85    __asm__("movl %0,%%cr3\n\t"
  86            : /* no outputs */
  87            : "r" (PageDir));
  88 #elif defined(_MSC_VER)
  89           __asm mov eax, PageDir;
  90           __asm mov cr3, eax;
  91 #else
  92 #error Unknown compiler for inline assembler
  93 #endif
  94    KeLowerIrql(oldlvl);
  95 }
  96
  97 /*
  98  * @implemented
  99  */
 100 VOID STDCALL
 101 KeDetachProcess (VOID)
 102 {
 103    KIRQL oldlvl;
 104    PETHREAD CurrentThread;
 105    ULONG PageDir;
 106
 107    DPRINT("KeDetachProcess()\n");
 108
 109    CurrentThread = PsGetCurrentThread();
 110
 111    if (CurrentThread->OldProcess == NULL)
 112      {
 113         DbgPrint("Invalid detach (thread was not attached)\n");
 114         KEBUGCHECK(0);
 115      }
 116
 117    KeRaiseIrql(DISPATCH_LEVEL, &oldlvl);
 118
 119    KiSwapApcEnvironment(&CurrentThread->Tcb, &CurrentThread->OldProcess->Pcb);
 120
 121    CurrentThread->ThreadsProcess = CurrentThread->OldProcess;
 122    CurrentThread->OldProcess = NULL;
 123    PageDir = CurrentThread->ThreadsProcess->Pcb.DirectoryTableBase.u.LowPart;
 124 #if defined(__GNUC__)
 125    __asm__("movl %0,%%cr3\n\t"
 126            : /* no inputs */
 127            : "r" (PageDir));
 128 #elif defined(_MSC_VER)
 129           __asm mov eax, PageDir;
 130           __asm mov cr3, eax;
 131 #else
 132 #error Unknown compiler for inline assembler
 133 #endif
 134
 135    KeLowerIrql(oldlvl);
 136 }
 137
 138 /* EOF */