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2785dc7b SG |
1 | /* |
2 | * PVH Option ROM | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
16 | * | |
17 | * Copyright Novell Inc, 2009 | |
18 | * Authors: Alexander Graf <agraf@suse.de> | |
19 | * | |
20 | * Copyright (c) 2019 Red Hat Inc. | |
21 | * Authors: Stefano Garzarella <sgarzare@redhat.com> | |
22 | */ | |
23 | ||
24 | #include "optionrom.h" | |
25 | ||
26 | #define BOOT_ROM_PRODUCT "PVH loader" | |
27 | ||
28 | #define GS_PROT_JUMP 0 | |
29 | #define GS_GDT_DESC 6 | |
30 | ||
31 | #ifdef OPTION_ROM_START | |
32 | #undef OPTION_ROM_START | |
33 | #endif | |
34 | #ifdef OPTION_ROM_END | |
35 | #undef OPTION_ROM_END | |
36 | #endif | |
37 | ||
38 | /* | |
39 | * Redefine OPTION_ROM_START and OPTION_ROM_END, because this rom is produced | |
40 | * linking multiple objects. | |
41 | * signrom.py will add padding. | |
42 | */ | |
43 | #define OPTION_ROM_START \ | |
44 | .code16; \ | |
45 | .text; \ | |
46 | .global _start; \ | |
47 | _start:; \ | |
48 | .short 0xaa55; \ | |
49 | .byte 3; /* desired size in 512 units */ | |
50 | ||
51 | #define OPTION_ROM_END \ | |
52 | _end: | |
53 | ||
54 | BOOT_ROM_START | |
55 | ||
56 | run_pvhboot: | |
57 | ||
58 | cli | |
59 | cld | |
60 | ||
61 | mov %cs, %eax | |
62 | shl $0x4, %eax | |
63 | ||
64 | /* set up a long jump descriptor that is PC relative */ | |
65 | ||
66 | /* move stack memory to %gs */ | |
67 | mov %ss, %ecx | |
68 | shl $0x4, %ecx | |
69 | mov %esp, %ebx | |
70 | add %ebx, %ecx | |
71 | sub $0x20, %ecx | |
72 | sub $0x30, %esp | |
73 | shr $0x4, %ecx | |
74 | mov %cx, %gs | |
75 | ||
76 | /* now push the indirect jump descriptor there */ | |
77 | mov (prot_jump), %ebx | |
78 | add %eax, %ebx | |
79 | movl %ebx, %gs:GS_PROT_JUMP | |
80 | mov $8, %bx | |
81 | movw %bx, %gs:GS_PROT_JUMP + 4 | |
82 | ||
83 | /* fix the gdt descriptor to be PC relative */ | |
84 | movw (gdt_desc), %bx | |
85 | movw %bx, %gs:GS_GDT_DESC | |
86 | movl (gdt_desc+2), %ebx | |
87 | add %eax, %ebx | |
88 | movl %ebx, %gs:GS_GDT_DESC + 2 | |
89 | ||
90 | /* initialize HVM memmap table using int 0x15(e820) */ | |
91 | ||
92 | /* ES = pvh_e820 struct */ | |
93 | mov $pvh_e820, %eax | |
94 | shr $4, %eax | |
95 | mov %ax, %es | |
96 | ||
97 | /* start storing memmap table at %es:8 (pvh_e820.table) */ | |
98 | mov $8,%edi | |
99 | xor %ebx, %ebx | |
100 | jmp memmap_loop | |
101 | ||
102 | memmap_loop_check: | |
103 | /* pvh_e820 can contains up to 128 entries */ | |
104 | cmp $128, %ebx | |
105 | je memmap_done | |
106 | ||
107 | memmap_loop: | |
108 | /* entry size (hvm_memmap_table_entry) & max buffer size (int15) */ | |
109 | movl $24, %ecx | |
110 | /* e820 */ | |
111 | movl $0x0000e820, %eax | |
112 | /* 'SMAP' magic */ | |
113 | movl $0x534d4150, %edx | |
114 | /* store counter value at %es:0 (pvh_e820.entries) */ | |
115 | movl %ebx, %es:0 | |
116 | ||
117 | int $0x15 | |
118 | /* error or last entry already done? */ | |
119 | jb memmap_err | |
120 | ||
121 | /* %edi += entry size (hvm_memmap_table_entry) */ | |
122 | add $24, %edi | |
123 | ||
124 | /* continuation value 0 means last entry */ | |
125 | test %ebx, %ebx | |
126 | jnz memmap_loop_check | |
127 | ||
128 | /* increase pvh_e820.entries to save the last entry */ | |
129 | movl %es:0, %ebx | |
130 | inc %ebx | |
131 | ||
132 | memmap_done: | |
133 | movl %ebx, %es:0 | |
134 | ||
135 | memmap_err: | |
136 | ||
137 | /* load the GDT before going into protected mode */ | |
138 | lgdt: | |
139 | data32 lgdt %gs:GS_GDT_DESC | |
140 | ||
141 | /* get us to protected mode now */ | |
142 | movl $1, %eax | |
143 | movl %eax, %cr0 | |
144 | ||
145 | /* the LJMP sets CS for us and gets us to 32-bit */ | |
146 | ljmp: | |
147 | data32 ljmp *%gs:GS_PROT_JUMP | |
148 | ||
149 | prot_mode: | |
150 | .code32 | |
151 | ||
152 | /* initialize all other segments */ | |
153 | movl $0x10, %eax | |
154 | movl %eax, %ss | |
155 | movl %eax, %ds | |
156 | movl %eax, %es | |
157 | movl %eax, %fs | |
158 | movl %eax, %gs | |
159 | ||
160 | jmp pvh_load_kernel | |
161 | ||
162 | /* Variables */ | |
163 | .align 4, 0 | |
164 | prot_jump: .long prot_mode | |
165 | .short 8 | |
166 | ||
167 | .align 4, 0 | |
168 | gdt: | |
169 | /* 0x00 */ | |
170 | .byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 | |
171 | ||
172 | /* | |
173 | * 0x08: code segment | |
174 | * (base=0, limit=0xfffff, type=32bit code exec/read, DPL=0, 4k) | |
175 | */ | |
176 | .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00 | |
177 | ||
178 | /* | |
179 | * 0x10: data segment | |
180 | * (base=0, limit=0xfffff, type=32bit data read/write, DPL=0, 4k) | |
181 | */ | |
182 | .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00 | |
183 | ||
184 | /* | |
185 | * 0x18: code segment | |
186 | * (base=0, limit=0x0ffff, type=16bit code exec/read/conf, DPL=0, 1b) | |
187 | */ | |
188 | .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9e, 0x00, 0x00 | |
189 | ||
190 | /* | |
191 | * 0x20: data segment | |
192 | * (base=0, limit=0x0ffff, type=16bit data read/write, DPL=0, 1b) | |
193 | */ | |
194 | .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0x00, 0x00 | |
195 | ||
196 | gdt_desc: | |
197 | .short (5 * 8) - 1 | |
198 | .long gdt | |
199 | ||
200 | BOOT_ROM_END |