MdePkg/Library/BaseLib/Ia32/EnablePaging64.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, 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.S
  15 #
  16 # Abstract:
  17 #
  18 #   InternalX86EnablePaging64 function
  19 #
  20 # Notes:
  21 #
  22 #------------------------------------------------------------------------------
  23
  24 ASM_GLOBAL ASM_PFX(InternalX86EnablePaging64)
  25
  26 #------------------------------------------------------------------------------
  27 # VOID
  28 # EFIAPI
  29 # InternalX86EnablePaging64 (
  30 #   IN      UINT16                    CodeSelector,
  31 #   IN      UINT64                    EntryPoint,
  32 #   IN      UINT64                    Context1,    OPTIONAL
  33 #   IN      UINT64                    Context2,    OPTIONAL
  34 #   IN      UINT64                    NewStack
  35 #   );
  36 #------------------------------------------------------------------------------
  37 ASM_PFX(InternalX86EnablePaging64):
  38     cli
  39     movl    $LongStart, (%esp)          # offset for far retf, seg is the 1st arg
  40     movl    %cr4, %eax
  41     orb     $0x20, %al
  42     movl    %eax, %cr4                  # enable PAE
  43     movl    $0xc0000080, %ecx
  44     rdmsr
  45     orb     $1, %ah                     # set LME
  46     wrmsr
  47     movl    %cr0, %eax
  48     btsl    $31, %eax                   # set PG
  49     movl    %eax, %cr0                  # enable paging
  50     lret                                # topmost 2 dwords hold the address
  51 LongStart:                              # long mode starts here
  52     .byte   0x67, 0x48                  # 32-bit address size, 64-bit operand size
  53     movl    (%esp), %ebx                # mov rbx, [esp]
  54     .byte   0x67, 0x48
  55     movl    8(%esp), %ecx               # mov rcx, [esp + 8]
  56     .byte   0x67, 0x48
  57     movl    0x10(%esp), %edx            # mov rdx, [esp + 10h]
  58     .byte   0x67, 0x48
  59     movl    0x18(%esp), %esp            # mov rsp, [esp + 18h]
  60     .byte   0x48
  61     addl    $0x-0x20, %esp              # add rsp, -20h
  62     call    *%ebx                       # call rbx
  63     jmp     .                           # no one should get here