getfreevirtualpage.c

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/*****************************************************************************************
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 $Id: getfreevirtualpage_8c-source.html 88 2016-01-12 00:11:29Z reddawg $

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

#include <vmm/vmm.h>
#include <ubixos/sched.h>
#include <ubixos/kpanic.h>
#include <ubixos/spinlock.h>
#include <lib/kprint.h>

static spinLock_t fvpSpinLock = SPIN_LOCK_INITIALIZER;

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

Function: void *vmmGetFreeVirtualPage(pidType pid,int count);
Description: Returns A Free Page Mapped To The VM Space
Notes:

08/11/02 - This Will Return Next Avilable Free Page Of Tasks VM Space

************************************************************************/
void *vmmGetFreeVirtualPage(pidType pid, int count,int type) {
  int             x = 0, y = 0, c = 0;
  uInt32         *pageTableSrc = 0x0;
  uInt32         *pageDir = 0x0;
  uInt32          start_page = 0x0;

  
  spinLock(&fvpSpinLock);
  
  pageDir = (uInt32 *) parentPageDirAddr;

  /* Lets Search For A Free Page */
  if (_current->oInfo.vmStart <= 0x100000)
    kpanic("Invalid vmStart\n");

  if (type == VM_THRD) {
    start_page = (uint32_t)(_current->td.vm_daddr + ctob(_current->td.vm_dsize));
    }
  else if (type == VM_TASK) {
    //kprintf("vmStart");
    start_page = _current->oInfo.vmStart;
    }
  else
    K_PANIC("Invalid Type");

  //for (x = ((_current->td.vm_daddr + _current->td.vm_dsize) / (1024 * 4096)); x < 1024; x++) {
  for (x = (start_page / (1024 * 4096)); x < 1024; x++) {
    /* Set Page Table Address */
    if ((pageDir[x] & PAGE_PRESENT) != PAGE_PRESENT) {
      /* If Page Table Is Non Existant Then Set It Up */
      pageDir[x] = (uInt32) vmmFindFreePage(_current->id) | PAGE_DEFAULT;
      /* Also Add It To Virtual Space So We Can Make Changes Later */
      pageTableSrc = (uInt32 *) (tablesBaseAddress + (4096 * 767));
      pageTableSrc[x] = pageDir[x];
      y = 1;
      /* Reload Page Directory */
      asm(
          "movl %cr3,%eax\n"
          "movl %eax,%cr3\n"
        );
    }
    pageTableSrc = (uInt32 *) (tablesBaseAddress + (0x1000 * x));
    if (y != 0x0) {
      for (y = 0x0;y<pageEntries;y++) {
        pageTableSrc[y] = (uInt32)0x0;
        }
      }
    for (y = 0; y < 1024; y++) {
      /* Loop Through The Page Table Find An UnAllocated Page */
      if ((pageTableSrc[y] & PAGE_COW) == PAGE_COW) {
        kprintf("PAGE_COW");
        //_current->td.vm_dsize += btoc(0x1000);
        /* HACK MEMORY LEAK */
        //pageTableSrc[y] = 0x0;
        }
      if ((uInt32) pageTableSrc[y] == (uInt32) 0x0) {
        if (count > 0x1) {
          for (c = 0; c < count; c++) {
            if (y + c < 1024) {
      if ((pageTableSrc[y + c] & PAGE_COW) == PAGE_COW) {
        kprintf("PAGE-COW");
        //_current->td.vm_dsize += btoc(0x1000);
        /* HACK MEMORY LEAK */
        //pageTableSrc[y + c] = 0x0;
        }

              if ((uInt32) pageTableSrc[y + c] != (uInt32) 0x0) {
                c = -1;
                break;
                }
              }
            }
          if (c != -1) {
            for (c = 0; c < count; c++) {
              if ((vmm_remapPage((uInt32) vmmFindFreePage(pid), ((x * (1024 * 4096)) + ((y + c) * 4096)),PAGE_DEFAULT)) == 0x0)
                kpanic("vmmRemapPage: getFreeVirtualPage-1: [0x%X]\n",((x * (1024 * 4096)) + ((y + c) * 4096)));
              vmmClearVirtualPage((uInt32) ((x * (1024 * 4096)) + ((y + c) * 4096)));
            }
            if (type == VM_THRD)
              _current->td.vm_dsize += btoc(count * 0x1000);
            spinUnlock(&fvpSpinLock);
            return ((void *)((x * (1024 * 4096)) + (y * 4096)));
          }
        } else {
          /* Map A Physical Page To The Virtual Page */

          /*
           * remapPage((uInt32)vmmFindFreePage(pid),((x*(1024*4096))+(y*4096))
           * ,pid);
           */
          if ((vmm_remapPage((uInt32) vmmFindFreePage(pid), ((x * (1024 * 4096)) + (y * 4096)),PAGE_DEFAULT)) == 0x0)
            kpanic("vmmRemapPage: getFreeVirtualPage-2\n");

          /* Clear This Page So No Garbage Is There */
          vmmClearVirtualPage((uInt32) ((x * (1024 * 4096)) + (y * 4096)));

          /* Return The Address Of The Newly Allocate Page */
          if (type == VM_THRD) {
            _current->td.vm_dsize += btoc(count * 0x1000);
            kprintf("vm_dsize: [0x%X]][0x%X]\n",ctob(_current->td.vm_dsize),_current->td.vm_dsize);
            }
          //kprintf("(0x%X:0x%X)",_current->td.vm_dsize,vmm_getPhysicalAddr(((x * (1024 * 4096)) + (y * 4096))));
//          kprintf("(0x%X:0x%X)",_current->td.vm_dsize + _current->td.vm_daddr,((x * (1024 * 4096)) + (y * 4096)));
          spinUnlock(&fvpSpinLock);
          return ((void *)((x * (1024 * 4096)) + (y * 4096)));
        }
      }
    }
  }
  /* If No Free Page Was Found Return NULL */
  spinUnlock(&fvpSpinLock);
  return (0x0);
}

/***
 END
 ***/

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