UefiCpuPkg/CpuMpPei/X64/MpFuncs.nasm

   1 ;------------------------------------------------------------------------------ ;
   2 ; Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
   3 ; This program and the accompanying materials
   4 ; are licensed and made available under the terms and conditions of the BSD License
   5 ; which accompanies this distribution.  The full text of the license may be found at
   6 ; http://opensource.org/licenses/bsd-license.php.
   7 ;
   8 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   9 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  10 ;
  11 ; Module Name:
  12 ;
  13 ;   MpFuncs.nasm
  14 ;
  15 ; Abstract:
  16 ;
  17 ;   This is the assembly code for MP support
  18 ;
  19 ;-------------------------------------------------------------------------------
  20
  21 %include "MpEqu.inc"
  22 DEFAULT REL
  23 SECTION .text
  24
  25 global ASM_PFX(AsmInitializeGdt)
  26 ASM_PFX(AsmInitializeGdt):
  27     push       rbp
  28     mov        rbp, rsp
  29
  30     lgdt       [rcx]  ; update the GDTR
  31
  32     sub        rsp, 0x10
  33     mov        rax, ASM_PFX(SetCodeSelectorFarJump)
  34     mov        [rsp], rax
  35     mov        rdx, LONG_MODE_CS
  36     mov        [rsp + 4], dx    ; get new CS
  37     jmp        far dword [rsp]  ; far jump with new CS
  38 ASM_PFX(SetCodeSelectorFarJump):
  39     add        rsp, 0x10
  40
  41     mov        rax, LONG_MODE_DS          ; get new DS
  42     mov        ds, ax
  43     mov        es, ax
  44     mov        fs, ax
  45     mov        gs, ax
  46     mov        ss, ax
  47
  48     pop        rbp
  49
  50   ret