MdePkg/Library/BaseLib/Ia32/EnablePaging64.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006, Intel Corporation
   4 ; All rights reserved. This program and the accompanying materials
   5 ; are licensed and made available under the terms and conditions of the BSD License
   6 ; which accompanies this distribution.  The full text of the license may be found at
   7 ; http://opensource.org/licenses/bsd-license.php
   8 ;
   9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 ;
  12 ; Module Name:
  13 ;
  14 ;   EnablePaging64.Asm
  15 ;
  16 ; Abstract:
  17 ;
  18 ;   AsmEnablePaging64 function
  19 ;
  20 ; Notes:
  21 ;
  22 ;------------------------------------------------------------------------------
  23
  24     .686p
  25     .model  flat,C
  26     .code
  27
  28 InternalX86EnablePaging64 PROC
  29     cli
  30
  31     mov     ebx, [esp + 4]              ; save CS
  32     mov     eax, OFFSET cs_address
  33     mov     word ptr [eax], bx          ; Update CS selector for far jump
  34
  35     mov     eax, cr4
  36     or      al, (1 SHL 5)
  37     mov     cr4, eax                    ; enable PAE
  38     mov     ecx, 0c0000080h
  39     rdmsr
  40     or      ah, 1                       ; set LME
  41     wrmsr
  42     mov     eax, cr0
  43     bts     eax, 31
  44     mov     cr0, eax                    ; enable paging
  45     retf
  46     jmp     go_to_long_mode
  47 go_to_long_mode:
  48
  49     ;
  50     ; This is the next instruction after enabling paging.  Jump to long mode
  51     ;
  52     db      067h
  53     db      0eah                        ;   Far Jump Offset:Selector to reload CS
  54     dd      OFFSET in_long_mode         ;   Offset is ensuing instruction boundary
  55 cs_address:
  56     dw      0h                          ;   CS selector will be updated at runtime
  57
  58 in_long_mode:                           ; now in long mode
  59     DB      67h, 48h
  60     mov     ebx, [esp + 8]              ; mov rbx, [esp]
  61     DB      67h, 48h
  62     mov     ecx, [esp + 10h]            ; mov rcx, [esp + 8]
  63     DB      67h, 48h
  64     mov     edx, [esp + 18h]            ; mov rdx, [esp + 10h]
  65     DB      67h, 48h
  66     mov     esp, [esp + 20h]            ; mov rsp, [esp + 18h]
  67     DB      48h
  68     call    ebx                         ; call rbx
  69     jmp     $
  70 InternalX86EnablePaging64 ENDP
  71
  72     END