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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
; $Id: bootsector-pae.asm $
;; @file
; Bootsector that switches the CPU info PAE mode.
;
;
; Copyright (C) 2007-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
%include "iprt/asmdefs.mac"
%include "iprt/x86.mac"
%include "VBox/bios.mac"
;; The boot sector load address.
%define BS_ADDR 0x7c00
%define PDP_ADDR 0x9000
%define PD_ADDR 0xa000
BITS 16
start:
; Start with a jump just to follow the convention.
jmp short the_code
nop
times 3ah db 0
the_code:
cli
xor edx, edx
mov ds, dx ; Use 0 based addresses
;
; Create a paging hierarchy
;
mov cx, 4
xor esi, esi ; physical address
mov ebx, PDP_ADDR
mov edi, PD_ADDR
pdptr_loop:
; The page directory pointer entry.
mov dword [ebx], edi
or word [bx], X86_PDPE_P
mov dword [ebx + 4], edx
; The page directory.
pd_loop:
mov dword [edi], esi
or word [di], X86_PDE4M_P | X86_PDE4M_RW | X86_PDE4M_PS
mov dword [edi + 4], 0
add esi, 0x00200000 ; 2MB
add di, 8
test di, 0fffh
jnz pd_loop
add bx, 8
loop pdptr_loop
;
; Switch to protected mode.
;
lgdt [(gdtr - start) + BS_ADDR]
lidt [(idtr_null - start) + BS_ADDR]
mov eax, PDP_ADDR
mov cr3, eax
mov eax, cr4
or eax, X86_CR4_PAE | X86_CR4_PSE
mov cr4, eax
mov eax, cr0
or eax, X86_CR0_PE | X86_CR0_PG
mov cr0, eax
jmp far 0x0008:((code32_start - start) + BS_ADDR) ; 8=32-bit CS
BITS 32
code32_start:
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ax, 0x18
mov es, ax
mov esp, 0x80000
; eye catchers
mov eax, 0xCafeBabe
mov ebx, eax
mov ecx, eax
mov edx, eax
mov edi, eax
mov esi, eax
mov ebp, eax
;
; Boch shutdown request.
;
mov bl, 64
mov dx, VBOX_BIOS_SHUTDOWN_PORT
mov ax, VBOX_BIOS_OLD_SHUTDOWN_PORT
retry:
mov ecx, 8
mov esi, (szShutdown - start) + BS_ADDR
rep outsb
xchg dx, ax ; alternate between the new (VBox) and old (Bochs) ports.
dec bl
jnz retry
; Shutdown failed!
hlt_again:
hlt
cli
jmp hlt_again
;
; The GDT.
;
align 8, db 0
gdt:
dw 0, 0, 0, 0 ; null selector
dw 0xffff, 0, 0x9b00, 0x00cf ; 32 bit flat code segment (0x08)
dw 0xffff, 0, 0x9300, 0x00cf ; 32 bit flat data segment (0x10)
dw 0xffff, 0, 0x9300, 0x00cf ; 32 bit flat stack segment (0x18)
gdtr:
dw 8*4-1 ; limit 15:00
dw (gdt - start) + BS_ADDR ; base 15:00
db 0 ; base 23:16
db 0 ; unused
idtr_null:
dw 0 ; limit 15:00
dw (gdt - start) + BS_ADDR ; base 15:00
db 0 ; base 23:16
db 0 ; unused
szShutdown:
db 'Shutdown', 0
;
; Padd the remainder of the sector with zeros and
; end it with the dos signature.
;
padding:
times 510 - (padding - start) db 0
db 055h, 0aah
|
