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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
/* $OpenBSD: pxe_call.S,v 1.5 2022/12/08 01:25:44 guenther Exp $ */
/* $NetBSD: pxe_call.S,v 1.2 2002/03/27 17:24:22 kanaoka Exp $ */
/*
* Copyright 2001 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Jason R. Thorpe for Wasabi Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Low level PXE BIOS call glue.
*/
#include <machine/asm.h>
#include <assym.h>
#include "gidt.h"
ENTRY(pxecall_bangpxe)
.code32
pushl %ebp
movl %esp, %ebp
pushl %ebx
pushl %ecx
pushl %edx
/* For simplicity, just move all 32 bits. */
movl 8(%ebp), %ebx
pushw pxe_command_buf_seg
pushw pxe_command_buf_off
pushw %bx
call prot_to_real /* Enter real mode */
.code16
sti
/* The encoding is: 0x9a offlo offhi seglo seghi */
lcall $0, $0xffff
.globl bangpxe_off
bangpxe_off = . - 4
.globl bangpxe_seg
bangpxe_seg = . - 2
cli
call real_to_prot /* Leave real mode */
.code32
add $6, %esp
popl %edx
popl %ecx
popl %ebx
popl %ebp
ret
ENTRY(pxecall_pxenv)
.code32
pushl %ebp
movl %esp, %ebp
pushl %ebx
pushl %ecx
pushl %edx
pushl %edi
/*
* Using the PXENV+ calling convention, the (16 bit) function
* number is passed in %bx, with the address of the command
* buffer in %es:%di.
*/
movl 8(%ebp), %ebx /* For simplicity, just move all 32 bits. */
/*
* prot_to_real() will set %es to BOOTSEG, so we just need to set
* %(e)di up here. Remember to relocate it!
*/
movl $pxe_command_buf, %edi
subl $LINKADDR, %edi
call prot_to_real /* Enter real mode */
.code16
/* The encoding is: 0x9a offlo offhi seglo seghi */
lcall $0, $0xffff
.globl pxenv_off
pxenv_off = . - 4
.globl pxenv_seg
pxenv_seg = . - 2
call real_to_prot /* Leave real mode */
.code32
popl %edi
popl %edx
popl %ecx
popl %ebx
popl %ebp
ret
/*
* prot_to_real()
*
* Switch the processor back into real mode.
*/
.globl prot_to_real
prot_to_real:
.code32
ljmp $S16TEXT, $p2r16 - LINKADDR
p2r16:
.code16
movw $S16DATA, %ax
movw %ax, %ds
movw %ax, %es
movl %cr0, %eax /* Disable protected mode */
andl $~CR0_PE, %eax
movl %eax, %cr0
/* reload real cs:ip */
data32 ljmp $(LINKADDR >> 4), $p2r16real - LINKADDR
p2r16real:
xorw %ax, %ax /* Reset segment registers: */
movw %ax, %ss /* %ss: for our stack */
movw $LINKADDR >> 4, %ax /* We're linked to LINKADDR/16:0000 */
movw %ax, %ds /* %ds: so we can get at Idtr_real */
.extern Idtr_real
data32 addr32 lidt (Idtr_real - LINKADDR); /* Set up IDT for real mode */
movw %cs, %ax
movw %ax, %ds
movw %ax, %es /* Set %ds = %es = %cs */
/*
* We were called from 32-bit mode, so there's a 32-bit
* return address on the stack. No segment. This is within
* the flat memory model, so we need to adjust it back so
* that it's relative to our 16-bit %cs.
*/
popl %eax
subl $LINKADDR, %eax
pushw %ax
ret
/*
* real_to_prot()
*
* Switch the processor back into protected mode.
*/
.globl real_to_prot
real_to_prot:
.code16
movw $LINKADDR >> 4, %ax /* We're linked to LINKADDR/16:0000 */
movw %ax, %ds
data32 addr32 lgdt (Gdtr - LINKADDR) /* Reload the GDT */
movl %cr0, %eax /* Enable protected mode */
orl $CR0_PE, %eax
movl %eax, %cr0
data32 ljmp $S32TEXT, $r2p32 /* Reload %cs, flush pipeline */
r2p32:
.code32
/* Reload 32-bit %ds, %ss, %es */
movl $S32DATA, %eax
mov %ax, %ds
mov %ax, %ss
mov %ax, %es
/* Load IDT for debugger and DOS/BIOS interface */
.extern Idtr
lidt Idtr
xorl %eax, %eax
popw %ax /* 16-bit return addr on stack */
addl $LINKADDR, %eax
pushl %eax /* Now have correct 32-bit ret addr */
ret
.end
|
