IntelFsp2Pkg/Library/SecFspSecPlatformLibNull/Ia32/Flat32.nasm

   1 ;; @file
   2 ;  This is the code that goes from real-mode to protected mode.
   3 ;  It consumes the reset vector, configures the stack.
   4 ;
   5 ; Copyright (c) 2015 - 2018, Intel Corporation. All rights reserved.<BR>
   6 ; This program and the accompanying materials
   7 ; are licensed and made available under the terms and conditions of the BSD License
   8 ; which accompanies this distribution.  The full text of the license may be found at
   9 ; http://opensource.org/licenses/bsd-license.php.
  10 ;
  11 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13 ;;
  14
  15 ;
  16 ; Define assembler characteristics
  17 ;
  18
  19 extern   ASM_PFX(TempRamInitApi)
  20
  21 SECTION .text
  22
  23 %macro RET_ESI  0
  24
  25   movd    esi, mm7                      ; restore ESP from MM7
  26   jmp     esi
  27
  28 %endmacro
  29
  30 ;
  31 ; Perform early platform initialization
  32 ;
  33 global ASM_PFX(SecPlatformInit)
  34 ASM_PFX(SecPlatformInit):
  35
  36   RET_ESI
  37
  38 ;
  39 ; Protected mode portion initializes stack, configures cache, and calls C entry point
  40 ;
  41
  42 ;----------------------------------------------------------------------------
  43 ;
  44 ; Procedure:    ProtectedModeEntryPoint
  45 ;
  46 ; Input:        Executing in 32 Bit Protected (flat) mode
  47 ;               cs: 0-4GB
  48 ;               ds: 0-4GB
  49 ;               es: 0-4GB
  50 ;               fs: 0-4GB
  51 ;               gs: 0-4GB
  52 ;               ss: 0-4GB
  53 ;
  54 ; Output:       This function never returns
  55 ;
  56 ; Destroys:
  57 ;               ecx
  58 ;               edi
  59 ;               esi
  60 ;               esp
  61 ;
  62 ; Description:
  63 ;               Perform any essential early platform initilaisation
  64 ;               Setup a stack
  65 ;
  66 ;----------------------------------------------------------------------------
  67 global ASM_PFX(ProtectedModeEntryPoint)
  68 ASM_PFX(ProtectedModeEntryPoint):
  69   ;
  70   ; Dummy function. Consume 2 API to make sure they can be linked.
  71   ;
  72   mov  eax, ASM_PFX(TempRamInitApi)
  73
  74   ; Should never return
  75   jmp  $
  76
  77 ;
  78 ; ROM-based Global-Descriptor Table for the PEI Phase
  79 ;
  80 align 16
  81 global  ASM_PFX(BootGdtTable)
  82
  83 ;
  84 ; GDT[0]: 0x00: Null entry, never used.
  85 ;
  86 NULL_SEL        equ     $ - GDT_BASE        ; Selector [0]
  87 GDT_BASE:
  88 ASM_PFX(BootGdtTable):    DD      0
  89                           DD      0
  90 ;
  91 ; Linear code segment descriptor
  92 ;
  93 LINEAR_CODE_SEL equ     $ - GDT_BASE        ; Selector [0x8]
  94         DW      0FFFFh                      ; limit 0xFFFF
  95         DW      0                           ; base 0
  96         DB      0
  97         DB      09Bh                        ; present, ring 0, data, expand-up, not-writable
  98         DB      0CFh                        ; page-granular, 32-bit
  99         DB      0
 100 ;
 101 ; System data segment descriptor
 102 ;
 103 SYS_DATA_SEL    equ     $ - GDT_BASE        ; Selector [0x10]
 104         DW      0FFFFh                      ; limit 0xFFFF
 105         DW      0                           ; base 0
 106         DB      0
 107         DB      093h                        ; present, ring 0, data, expand-up, not-writable
 108         DB      0CFh                        ; page-granular, 32-bit
 109         DB      0
 110
 111 GDT_SIZE        EQU     $ - GDT_BASE        ; Size, in bytes
 112
 113 ;
 114 ; GDT Descriptor
 115 ;
 116 GdtDesc:                                    ; GDT descriptor
 117         DW      GDT_SIZE - 1                ; GDT limit
 118         DD      GDT_BASE                    ; GDT base address
 119
 120 global ASM_PFX(ProtectedModeEntryLinearAddress)
 121 global ASM_PFX(ProtectedModeEntryLinearOffset)
 122
 123 ASM_PFX(ProtectedModeEntryLinearAddress):
 124 ASM_PFX(ProtectedModeEntryLinearOffset):
 125   DD      ASM_PFX(ProtectedModeEntryPoint)  ; Offset of our 32 bit code
 126   DW      LINEAR_CODE_SEL
 127