MdePkg/Library/BaseLib/Ia32/DisablePaging32.c

   1 /** @file
   2   AsmDisablePaging32 function.
   3
   4   Copyright (c) 2006 - 2007, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 //
  16 // Include common header file for this module.
  17 //
  18 #include "CommonHeader.h"
  19
  20 __declspec (naked)
  21 VOID
  22 EFIAPI
  23 InternalX86DisablePaging32 (
  24   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  25   IN      VOID                      *Context1,    OPTIONAL
  26   IN      VOID                      *Context2,    OPTIONAL
  27   IN      VOID                      *NewStack
  28   )
  29 {
  30   _asm {
  31     push    ebp
  32     mov     ebp, esp
  33     mov     ebx, EntryPoint
  34     mov     ecx, Context1
  35     mov     edx, Context2
  36     pushfd
  37     pop     edi                         // save EFLAGS to edi
  38     cli
  39     mov     eax, cr0
  40     btr     eax, 31
  41     mov     esp, NewStack
  42     mov     cr0, eax
  43     push    edi
  44     popfd                               // restore EFLAGS from edi
  45     push    edx
  46     push    ecx
  47     call    ebx
  48     jmp     $                           // EntryPoint() should not return
  49   }
  50 }
  51