reactos/ntoskrnl/ke/i386/patpge.c

   1 /*
   2 * PROJECT:         ReactOS Kernel
   3 * LICENSE:         GPL - See COPYING in the top level directory
   4 * FILE:            ntoskrnl/ke/i386/patpge.c
   5 * PURPOSE:         Support for PAT and PGE (Large Pages)
   6 * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
   7 */
   8
   9 /* INCLUDES ******************************************************************/
  10
  11 #include <ntoskrnl.h>
  12 #define NDEBUG
  13 #include <debug.h>
  14
  15 /* GLOBALS *******************************************************************/
  16
  17 ULONG Ke386GlobalPagesEnabled;
  18
  19 /* FUNCTIONS *****************************************************************/
  20
  21 ULONG_PTR
  22 NTAPI
  23 Ki386EnableGlobalPage(IN volatile ULONG_PTR Context)
  24 {
  25     volatile PLONG Count = (PLONG)Context;
  26     ULONG Cr4, Cr3;
  27
  28     /* Disable interrupts */
  29     _disable();
  30
  31     /* Decrease CPU Count and loop until it's reached 0 */
  32     do {InterlockedDecrement(Count);} while (!*Count);
  33
  34     /* Now check if this is the Boot CPU */
  35     if (!KeGetPcr()->Number)
  36     {
  37         /* It is.FIXME: Patch KeFlushCurrentTb */
  38     }
  39
  40     /* Now get CR4 and make sure PGE is masked out */
  41     Cr4 = __readcr4();
  42     __writecr4(Cr4 & ~CR4_PGE);
  43
  44     /* Flush the TLB */
  45     Cr3 = __readcr3();
  46     __writecr3(Cr3);
  47
  48     /* Now enable PGE */
  49     __writecr4(Cr4 | CR4_PGE);
  50     Ke386GlobalPagesEnabled = TRUE;
  51
  52     /* Restore interrupts */
  53     _enable();
  54     return 0;
  55 }
  56
  57 VOID
  58 NTAPI
  59 KiInitializePAT(VOID)
  60 {
  61     /* FIXME: Support this */
  62     DPRINT1("Advanced Memory features detected but not yet taken advantage of.\n");
  63 }