1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
;; @file
; This is the code that goes from real-mode to protected mode.
; It consumes the reset vector, configures the stack.
;
; Copyright (c) 2015 - 2019, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;;
;
; Define assembler characteristics
;
extern ASM_PFX(TempRamInitApi)
SECTION .text
%macro RET_ESI 0
movd esi, mm7 ; restore ESP from MM7
jmp esi
%endmacro
;
; Perform early platform initialization
;
global ASM_PFX(SecPlatformInit)
ASM_PFX(SecPlatformInit):
RET_ESI
;
; Protected mode portion initializes stack, configures cache, and calls C entry point
;
;----------------------------------------------------------------------------
;
; Procedure: ProtectedModeEntryPoint
;
; Input: Executing in 32 Bit Protected (flat) mode
; cs: 0-4GB
; ds: 0-4GB
; es: 0-4GB
; fs: 0-4GB
; gs: 0-4GB
; ss: 0-4GB
;
; Output: This function never returns
;
; Destroys:
; ecx
; edi
; esi
; esp
;
; Description:
; Perform any essential early platform initialisation
; Setup a stack
;
;----------------------------------------------------------------------------
global ASM_PFX(ProtectedModeEntryPoint)
ASM_PFX(ProtectedModeEntryPoint):
;
; Dummy function. Consume 2 API to make sure they can be linked.
;
mov eax, ASM_PFX(TempRamInitApi)
; Should never return
jmp $
;
; ROM-based Global-Descriptor Table for the PEI Phase
;
align 16
global ASM_PFX(BootGdtTable)
;
; GDT[0]: 0x00: Null entry, never used.
;
NULL_SEL equ $ - GDT_BASE ; Selector [0]
GDT_BASE:
ASM_PFX(BootGdtTable): DD 0
DD 0
;
; Linear code segment descriptor
;
LINEAR_CODE_SEL equ $ - GDT_BASE ; Selector [0x8]
DW 0FFFFh ; limit 0xFFFF
DW 0 ; base 0
DB 0
DB 09Bh ; present, ring 0, data, expand-up, not-writable
DB 0CFh ; page-granular, 32-bit
DB 0
;
; System data segment descriptor
;
SYS_DATA_SEL equ $ - GDT_BASE ; Selector [0x10]
DW 0FFFFh ; limit 0xFFFF
DW 0 ; base 0
DB 0
DB 093h ; present, ring 0, data, expand-up, not-writable
DB 0CFh ; page-granular, 32-bit
DB 0
GDT_SIZE EQU $ - GDT_BASE ; Size, in bytes
;
; GDT Descriptor
;
GdtDesc: ; GDT descriptor
DW GDT_SIZE - 1 ; GDT limit
DD GDT_BASE ; GDT base address
global ASM_PFX(ProtectedModeEntryLinearAddress)
global ASM_PFX(ProtectedModeEntryLinearOffset)
ASM_PFX(ProtectedModeEntryLinearAddress):
ASM_PFX(ProtectedModeEntryLinearOffset):
DD ASM_PFX(ProtectedModeEntryPoint) ; Offset of our 32 bit code
DW LINEAR_CODE_SEL
|
