summaryrefslogtreecommitdiffstats
path: root/grub-core/mmap/i386/pc/mmap_helper.S
blob: 8e251a1f891d6003da100fc55ac14a8cdc27b9bd (plain)
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
/* Mmap management. */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2009  Free Software Foundation, Inc.
 *
 *  GRUB 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, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/symbol.h>

#define DS(x) ((x) - LOCAL (segstart))

LOCAL (segstart):
VARIABLE(grub_machine_mmaphook_start)
	.code16
VARIABLE(grub_machine_mmaphook_int12)
	push %ds
	push %cs
	pop %ds
#ifdef __APPLE__
	LOCAL(kblow_offset) = DS (LOCAL (kblow))
	movw LOCAL(kblow_offset), %ax
#else
	movw DS (LOCAL (kblow)), %ax
#endif
	pop %ds
	iret

VARIABLE(grub_machine_mmaphook_int15)
	pushf
	cmpw $0xe801, %ax
	jz LOCAL (e801)
	cmpw $0xe820, %ax
	jz LOCAL (e820)
	cmpb $0x88, %ah
	jz LOCAL (h88)
	popf
	/* ljmp */
	.byte	0xea
VARIABLE (grub_machine_mmaphook_int15offset)
	.word	0
VARIABLE (grub_machine_mmaphook_int15segment)
	.word	0

LOCAL (e801):
	popf
	push %ds
	push %cs
	pop %ds
#ifdef __APPLE__
	LOCAL(kbin16mb_offset) = DS (LOCAL (kbin16mb))
	LOCAL(m64kbin4gb_offset) = DS (LOCAL (m64kbin4gb))
	movw LOCAL(kbin16mb_offset), %ax
	movw LOCAL(m64kbin4gb_offset), %bx
#else
	movw DS (LOCAL (kbin16mb)), %ax
	movw DS (LOCAL (m64kbin4gb)), %bx
#endif
	movw %ax, %cx
	movw %bx, %dx
	pop %ds
	clc
	jmp LOCAL (iret_cf)

LOCAL (h88):
	popf
	push %ds
	push %cs
	pop %ds
#ifdef __APPLE__
	movw LOCAL(kbin16mb_offset), %ax
#else
	movw DS (LOCAL (kbin16mb)), %ax
#endif
	pop %ds
	clc
	jmp LOCAL (iret_cf)

LOCAL (e820):
	popf
	push %ds
	push %cs
	pop %ds
	cmpw $20, %cx
	jb LOCAL (errexit)
#ifdef __APPLE__
	LOCAL(mmap_num_offset) = DS (LOCAL (mmap_num))
	cmpw LOCAL(mmap_num_offset), %bx
#else
	cmpw DS (LOCAL (mmap_num)), %bx
#endif
	jae LOCAL (errexit)
	cmp $0x534d4150, %edx
	jne LOCAL (errexit)
	push %si
	push %di
	movw $20, %cx
#ifdef __APPLE__
	LOCAL(mmaphook_map_offset) = DS(LOCAL (mmaphook_mmap))
	movw $LOCAL(mmaphook_map_offset), %si
#else
	movw $(DS(LOCAL (mmaphook_mmap))), %si
#endif
	mov %bx, %ax
	imul $20, %ax
	add %ax, %si
	rep movsb
	pop %di
	pop %si
	movl $20, %ecx
	inc %bx
#ifdef __APPLE__
	cmpw LOCAL(mmap_num_offset), %bx
#else
	cmpw DS(LOCAL (mmap_num)), %bx
#endif
	jb LOCAL (noclean)
	xor %bx, %bx
LOCAL (noclean):
	mov $0x534d4150, %eax
	pop %ds
	clc
	jmp LOCAL (iret_cf)
LOCAL (errexit):
	mov $0x534d4150, %eax
	pop %ds
	xor %bx, %bx
	stc

LOCAL (iret_cf):
	push %bp
	mov %sp, %bp
	setc 6(%bp)
	pop %bp
	iret

VARIABLE(grub_machine_mmaphook_mmap_num)
LOCAL (mmap_num):
	.word 0
VARIABLE(grub_machine_mmaphook_kblow)
LOCAL (kblow):
	.word 0
VARIABLE (grub_machine_mmaphook_kbin16mb)
LOCAL (kbin16mb):
	.word 0
VARIABLE (grub_machine_mmaphook_64kbin4gb)
LOCAL (m64kbin4gb):
	.word 0
LOCAL (mmaphook_mmap):
	/* Memory map is placed just after the interrupt handlers. */
VARIABLE(grub_machine_mmaphook_end)
	.byte 0