MdePkg/Library/BaseLib/X64/DisableCache.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   4 # 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 #   DisableCache.S
  15 #
  16 # Abstract:
  17 #
  18 #   Set the CD bit of CR0 to 1, clear the NW bit of CR0 to 0, and flush all caches with a
  19 #   WBINVD instruction.
  20 #
  21 # Notes:
  22 #
  23 #------------------------------------------------------------------------------
  24
  25 #------------------------------------------------------------------------------
  26 # VOID
  27 # EFIAPI
  28 # AsmDisableCache (
  29 #   VOID
  30 #   );
  31 #------------------------------------------------------------------------------
  32 ASM_GLOBAL ASM_PFX(AsmDisableCache)
  33 ASM_PFX(AsmDisableCache):
  34     movq    %cr0, %rax
  35     btsq    $30, %rax
  36     btrq    $29, %rax
  37     movq    %rax, %cr0
  38     wbinvd
  39     ret