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 __declspec (naked)
  16 VOID
  17 EFIAPI
  18 InternalX86DisablePaging32 (
  19   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  20   IN      VOID                      *Context1,    OPTIONAL
  21   IN      VOID                      *Context2,    OPTIONAL
  22   IN      VOID                      *NewStack
  23   )
  24 {
  25   _asm {
  26     push    ebp
  27     mov     ebp, esp
  28     mov     ebx, EntryPoint
  29     mov     ecx, Context1
  30     mov     edx, Context2
  31     pushfd
  32     pop     edi                         // save EFLAGS to edi
  33     cli
  34     mov     eax, cr0
  35     btr     eax, 31
  36     mov     esp, NewStack
  37     mov     cr0, eax
  38     push    edi
  39     popfd                               // restore EFLAGS from edi
  40     push    edx
  41     push    ecx
  42     call    ebx
  43     jmp     $                           // EntryPoint() should not return
  44   }
  45 }
  46