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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
* trap.S: Trap and world switch handlers
*
* Leendert van Doorn, leendert@watson.ibm.com
* Copyright (c) 2005, International Business Machines Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*/
#include "machine.h"
#include "vm86.h"
#include "offsets.h"
/*
* All processor exception/faults/interrupts end up here.
*
* On an exception/fault, the processor pushes CS:EIP, SS, ESP and an
* optional error code onto the stack. The common_trap routine
* below saves the processor context and transfers control to trap()
* whose job it is to virtualize and pass on the trap.
*/
.macro TRAP_HANDLER trapno error
.text
.align 16
1: .if \error == 0
pushl $0 /* dummy error code */
.endif
pushl $\trapno
jmp common_trap
.section .rodata
.long 1b
.text
.endm
.section .rodata
.code32
.align 4
.global trap_handlers
trap_handlers:
TRAP_HANDLER 0, 0 /* divide error */
TRAP_HANDLER 1, 0 /* debug */
TRAP_HANDLER 2, 0 /* NMI interrupt */
TRAP_HANDLER 3, 0 /* breakpoint */
TRAP_HANDLER 4, 0 /* overflow */
TRAP_HANDLER 5, 0 /* BOUND range exceeded */
TRAP_HANDLER 6, 0 /* invalid opcode */
TRAP_HANDLER 7, 0 /* device not available */
TRAP_HANDLER 8, 1 /* double fault */
TRAP_HANDLER 9, 0 /* coprocessor segment overrun */
TRAP_HANDLER 10, 1 /* invalid TSS */
TRAP_HANDLER 11, 1 /* segment not present */
TRAP_HANDLER 12, 1 /* stack-segment fault */
TRAP_HANDLER 13, 1 /* general protection */
TRAP_HANDLER 14, 1 /* page fault */
TRAP_HANDLER 15, 0 /* reserved */
TRAP_HANDLER 16, 0 /* FPU floating-point error */
TRAP_HANDLER 17, 1 /* alignment check */
TRAP_HANDLER 18, 0 /* machine check */
TRAP_HANDLER 19, 0 /* SIMD floating-point error */
TRAP_HANDLER 20, 0 /* reserved */
TRAP_HANDLER 21, 0 /* reserved */
TRAP_HANDLER 22, 0 /* reserved */
TRAP_HANDLER 23, 0 /* reserved */
TRAP_HANDLER 24, 0 /* reserved */
TRAP_HANDLER 25, 0 /* reserved */
TRAP_HANDLER 26, 0 /* reserved */
TRAP_HANDLER 27, 0 /* reserved */
TRAP_HANDLER 28, 0 /* reserved */
TRAP_HANDLER 29, 0 /* reserved */
TRAP_HANDLER 30, 0 /* reserved */
TRAP_HANDLER 31, 0 /* reserved */
TRAP_HANDLER 32, 0 /* irq 0 */
TRAP_HANDLER 33, 0 /* irq 1 */
TRAP_HANDLER 34, 0 /* irq 2 */
TRAP_HANDLER 35, 0 /* irq 3 */
TRAP_HANDLER 36, 0 /* irq 4 */
TRAP_HANDLER 37, 0 /* irq 5 */
TRAP_HANDLER 38, 0 /* irq 6 */
TRAP_HANDLER 39, 0 /* irq 7 */
TRAP_HANDLER 40, 0 /* irq 8 */
TRAP_HANDLER 41, 0 /* irq 9 */
TRAP_HANDLER 42, 0 /* irq 10 */
TRAP_HANDLER 43, 0 /* irq 11 */
TRAP_HANDLER 44, 0 /* irq 12 */
TRAP_HANDLER 45, 0 /* irq 13 */
TRAP_HANDLER 46, 0 /* irq 14 */
TRAP_HANDLER 47, 0 /* irq 15 */
.text
.code32
.align 16
common_trap: /* common trap handler */
pushl %gs
pushl %fs
pushl %ds
pushl %es
pushal
movl $(DATA_SELECTOR), %eax /* make sure these are sane */
movl %eax, %ds
movl %eax, %es
movl %eax, %fs
movl %eax, %gs
movl %esp, %ebp
pushl %ebp
pushl 52(%ebp)
pushl 48(%ebp)
call trap /* trap(trapno, errno, regs) */
addl $12, %esp
trap_return:
popal
popl %es
popl %ds
popl %fs
popl %gs
addl $8, %esp /* skip trapno, errno */
iret
/* NOT REACHED */
/*
* A world switch to real mode occured. The hypervisor saved the
* executing context into "oldctx" and instantiated "newctx", which
* gets us here. Here we push a stack frame that is compatible with
* a trap frame (see above) so that we can handle this event as a
* regular trap.
*/
.text
.align 16
.globl switch_to_real_mode
switch_to_real_mode:
pushl oldctx+VMX_ASSIST_CTX_GS_SEL /* 16 to 32-bit transition */
pushl oldctx+VMX_ASSIST_CTX_FS_SEL
pushl oldctx+VMX_ASSIST_CTX_DS_SEL
pushl oldctx+VMX_ASSIST_CTX_ES_SEL
pushl oldctx+VMX_ASSIST_CTX_SS_SEL
pushl oldctx+VMX_ASSIST_CTX_ESP
pushl oldctx+VMX_ASSIST_CTX_EFLAGS
pushl oldctx+VMX_ASSIST_CTX_CS_SEL
pushl oldctx+VMX_ASSIST_CTX_EIP
pushl $-1 /* trapno, errno */
pushl $-1
pushl %gs
pushl %fs
pushl %ds
pushl %es
pushal
movl %esp, %ebp
pushl %ebp
call enter_real_mode
addl $4, %esp
jmp trap_return
/* NOT REACHED */
/*
* Switch to protected mode. At this point all the registers have
* been reloaded by trap_return and all we have to do is cause a
* world switch by turning on CR0.PE.
*/
.text
.align 16
.globl switch_to_protected_mode
switch_to_protected_mode:
movl oldctx+VMX_ASSIST_CTX_CR0, %esp
movl %esp, %cr0 /* actual world switch ! */
/* NOT REACHED */
pushl $switch_failed
call panic
jmp .
.data
.align 4
switch_failed:
.asciz "World switch to protected mode failed\n"
|
