IntelFsp2Pkg/Library/SecFspSecPlatformLibNull/Ia32/Flat32.s

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2015 - 2016, 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 # Abstract:
  13 #
  14 #  This is the code that goes from real-mode to protected mode.
  15 #  It consumes the reset vector, configures the stack.
  16 #
  17 #------------------------------------------------------------------------------
  18
  19
  20 #
  21 # Contrary to the name, this file contains 16 bit code as well.
  22 #
  23 .text
  24
  25 ASM_GLOBAL ASM_PFX(SecPlatformInit)
  26 ASM_PFX(SecPlatformInit):
  27   movd    %mm7, %esi                      # restore ESP from MM7
  28   jmp     *%esi
  29
  30 #----------------------------------------------------------------------------
  31 #
  32 # Procedure:    ProtectedModeEntryPoint
  33 #
  34 # Input:        Executing in 32 Bit Protected (flat) mode
  35 #               cs: 0-4GB
  36 #               ds: 0-4GB
  37 #               es: 0-4GB
  38 #               fs: 0-4GB
  39 #               gs: 0-4GB
  40 #               ss: 0-4GB
  41 #
  42 # Output:       This function never returns
  43 #
  44 # Destroys:
  45 #               ecx
  46 #               edi
  47 #               esi
  48 #               esp
  49 #
  50 # Description:
  51 #               Perform any essential early platform initilaisation
  52 #               Setup a stack
  53 #
  54 #----------------------------------------------------------------------------
  55 ProtectedModeEntryPoint:
  56   #
  57   # Dummy function. Consume 2 API to make sure they can be linked.
  58   #
  59   movl   ASM_PFX(TempRamInitApi), %eax
  60   #
  61   # Should never return
  62   #
  63   jmp     . #'$'
  64
  65 #
  66 # ROM-based Global-Descriptor Table for the PEI Phase
  67 #
  68 .align 16
  69 #
  70 # GDT[0]: 000h: Null entry, never used.
  71 #
  72 .equ   NULL_SEL, . - GDT_BASE         # Selector [0]
  73 GDT_BASE:
  74 BootGdtTable:
  75         .long   0
  76         .long   0
  77 #
  78 # Linear code segment descriptor
  79 #
  80 .equ     LINEAR_CODE_SEL, . - GDT_BASE         # Selector [08h]
  81         .word   0xFFFF                      # limit 0FFFFh
  82         .word   0                           # base 0
  83         .byte   0
  84         .byte   0x9B                        # present, ring 0, data, expand-up, not-writable
  85         .byte   0xCF                        # page-granular, 32-bit
  86         .byte   0
  87 #
  88 # System data segment descriptor
  89 #
  90 .equ    SYS_DATA_SEL, . - GDT_BASE         # Selector [010h]
  91         .word   0xFFFF                      # limit 0FFFFh
  92         .word   0                           # base 0
  93         .byte   0
  94         .byte   0x93                        # present, ring 0, data, expand-up, not-writable
  95         .byte   0xCF                        # page-granular, 32-bit
  96         .byte   0
  97
  98 .equ            GDT_SIZE, . - BootGdtTable  # Size, in bytes
  99
 100 #
 101 # GDT Descriptor
 102 #
 103 GdtDesc:                                     # GDT descriptor
 104        .word    GDT_SIZE - 1
 105        .long    BootGdtTable
 106
 107 ProtectedModeEntryLinearAddress:
 108 ProtectedModeEntryLinearOffset:
 109        .long    ProtectedModeEntryPoint
 110        .word    LINEAR_CODE_SEL