unmappage.c

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/*****************************************************************************************
 Copyright (c) 2002-2004 The UbixOS Project
 All rights reserved.

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 conditions, the following disclaimer and the list of authors.  Redistributions in binary
 form must reproduce the above copyright notice, this list of conditions, the following
 disclaimer and the list of authors in the documentation and/or other materials provided
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 contributors may be used to endorse or promote products derived from this software
 without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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 OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 $Id: unmappage_8c-source.html 88 2016-01-12 00:11:29Z reddawg $

*****************************************************************************************/

#include <vmm/vmm.h>

/************************************************************************

Function: void vmmUnmapPage(uInt32 pageAddr,int flags);
Description: This Function Will Unmap A Page From The Kernel VM Space
             The Flags Variable Decides If Its To Free The Page Or Not
             A Flag Of 0 Will Free It And A Flag Of 1 Will Keep It
Notes:

07/30/02 - I Have Decided That This Should Free The Physical Page There
           Is No Reason To Keep It Marked As Not Available

07/30/02 - Ok A Found A Reason To Keep It Marked As Available I Admit
           Even I Am Not Perfect Ok The Case Where You Wouldn't Want To
           Free It Would Be On Something Like Where I Allocated A Page
           To Create A New Virtual Space So Now It Has A Flag

************************************************************************/
void 
vmmUnmapPage(uInt32 pageAddr, int flags)
{
  int             pageDirectoryIndex = 0, pageTableIndex = 0;
  uInt32         *pageTable = 0x0;

  /* Get The Index To The Page Directory */
  pageDirectoryIndex = (pageAddr >> 22);
  
  //Calculate The Page Table Index
  pageTableIndex = ((pageAddr >> 12) & 0x3FF);

  /* Set pageTable To The Virtual Address Of Table */
  pageTable = (uInt32 *) (tablesBaseAddress + (0x1000 * pageDirectoryIndex));
  /* Free The Physical Page If Flags Is 0 */
  if (flags == 0) {

    /*
     * This is temp i think its still an issue clearVirtualPage(pageAddr);
     * freePage((uInt32)(pageTable[pageTableIndex] & 0xFFFFF000));
     */
  }
  /* Unmap The Page */
  pageTable[pageTableIndex] = 0x0;
  /* Rehash The Page Directory */
  asm volatile(
      "movl %cr3,%eax\n"
      "movl %eax,%cr3\n"
    );
  /* Return */
  return;
}



/************************************************************************

Function: void vmmUnmapPages(uInt32 pageAddr,int flags);
Description: This Function Will Unmap A Page From The Kernel VM Space
             The Flags Variable Decides If Its To Free The Page Or Not
             A Flag Of 0 Will Free It And A Flag Of 1 Will Keep It
Notes:

07/30/02 - I Have Decided That This Should Free The Physical Page There
           Is No Reason To Keep It Marked As Not Available

07/30/02 - Ok A Found A Reason To Keep It Marked As Available I Admit
           Even I Am Not Perfect Ok The Case Where You Wouldn't Want To
           Free It Would Be On Something Like Where I Allocated A Page
           To Create A New Virtual Space So Now It Has A Flag

************************************************************************/
void vmmUnmapPages(void *ptr,uInt32 size) {
  uInt32 baseAddr = (uInt32)ptr & 0xFFFFF000;
  uInt32 dI = 0x0,tI = 0x0;
  uInt32 y = 0x0;
  uInt32 *pageTable = 0x0;

  dI = (baseAddr/(1024*4096));
  tI = ((baseAddr-(dI*(1024*4096)))/4096);
  pageTable = (uInt32 *)(tablesBaseAddress + (4096*dI));
  for (y=tI;y<(tI+((size+4095)/4096));y++) {
    pageTable[y] = 0x0;
    }
  return;
  }

/***
 $Log: unmappage_8c-source.html,v $
 Revision 1.7  2006/12/15 17:47:08  reddawg
 Updates

 Revision 1.1.1.1  2006/06/01 12:46:13  reddawg
 ubix2

 Revision 1.2  2005/10/12 00:13:38  reddawg
 Removed

 Revision 1.1.1.1  2005/09/26 17:24:54  reddawg
 no message

 Revision 1.4  2004/07/26 19:15:49  reddawg
 test code, fixes and the like

 Revision 1.3  2004/06/15 12:35:05  reddawg
 Cleaned Up

 Revision 1.2  2004/06/10 22:23:56  reddawg
 Volatiles

 Revision 1.1.1.1  2004/04/15 12:06:53  reddawg
 UbixOS v1.0

 Revision 1.7  2004/04/13 16:36:34  reddawg
 Changed our copyright, it is all now under a BSD-Style license

 END
 ***/

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