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3c0a051f | 1 | /** @file\r |
2 | Initialize GDT for Linux.\r | |
3 | \r | |
4 | Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>\r | |
5 | This program and the accompanying materials\r | |
6 | are licensed and made available under the terms and conditions of the BSD License\r | |
7 | which accompanies this distribution. The full text of the license may be found at\r | |
8 | http://opensource.org/licenses/bsd-license.php\r | |
9 | \r | |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
12 | \r | |
13 | **/\r | |
14 | \r | |
15 | #include "LoadLinuxLib.h"\r | |
16 | \r | |
17 | \r | |
18 | //\r | |
19 | // Local structure definitions\r | |
20 | //\r | |
21 | \r | |
22 | #pragma pack (1)\r | |
23 | \r | |
24 | //\r | |
25 | // Global Descriptor Entry structures\r | |
26 | //\r | |
27 | \r | |
28 | typedef struct _GDT_ENTRY {\r | |
29 | UINT16 Limit15_0;\r | |
30 | UINT16 Base15_0;\r | |
31 | UINT8 Base23_16;\r | |
32 | UINT8 Type;\r | |
33 | UINT8 Limit19_16_and_flags;\r | |
34 | UINT8 Base31_24;\r | |
35 | } GDT_ENTRY;\r | |
36 | \r | |
37 | typedef\r | |
38 | struct _GDT_ENTRIES {\r | |
39 | GDT_ENTRY Null;\r | |
40 | GDT_ENTRY Null2;\r | |
41 | GDT_ENTRY Linear;\r | |
42 | GDT_ENTRY LinearCode;\r | |
43 | GDT_ENTRY TaskSegment;\r | |
44 | GDT_ENTRY Spare4;\r | |
45 | GDT_ENTRY Spare5;\r | |
46 | } GDT_ENTRIES;\r | |
47 | \r | |
48 | #pragma pack ()\r | |
49 | \r | |
50 | STATIC GDT_ENTRIES *mGdt = NULL;\r | |
51 | \r | |
52 | //\r | |
53 | // Global descriptor table (GDT) Template\r | |
54 | //\r | |
55 | STATIC GDT_ENTRIES GdtTemplate = {\r | |
56 | //\r | |
57 | // Null\r | |
58 | //\r | |
59 | {\r | |
60 | 0x0, // limit 15:0\r | |
61 | 0x0, // base 15:0\r | |
62 | 0x0, // base 23:16\r | |
63 | 0x0, // type\r | |
64 | 0x0, // limit 19:16, flags\r | |
65 | 0x0, // base 31:24\r | |
66 | },\r | |
67 | //\r | |
68 | // Null2\r | |
69 | //\r | |
70 | {\r | |
71 | 0x0, // limit 15:0\r | |
72 | 0x0, // base 15:0\r | |
73 | 0x0, // base 23:16\r | |
74 | 0x0, // type\r | |
75 | 0x0, // limit 19:16, flags\r | |
76 | 0x0, // base 31:24\r | |
77 | },\r | |
78 | //\r | |
79 | // Linear\r | |
80 | //\r | |
81 | {\r | |
82 | 0x0FFFF, // limit 0xFFFFF\r | |
83 | 0x0, // base 0\r | |
84 | 0x0,\r | |
85 | 0x09A, // present, ring 0, data, expand-up, writable\r | |
86 | 0x0CF, // page-granular, 32-bit\r | |
87 | 0x0,\r | |
88 | },\r | |
89 | //\r | |
90 | // LinearCode\r | |
91 | //\r | |
92 | {\r | |
93 | 0x0FFFF, // limit 0xFFFFF\r | |
94 | 0x0, // base 0\r | |
95 | 0x0,\r | |
96 | 0x092, // present, ring 0, data, expand-up, writable\r | |
97 | 0x0CF, // page-granular, 32-bit\r | |
98 | 0x0,\r | |
99 | },\r | |
100 | //\r | |
101 | // TaskSegment\r | |
102 | //\r | |
103 | {\r | |
104 | 0x0, // limit 0\r | |
105 | 0x0, // base 0\r | |
106 | 0x0,\r | |
107 | 0x089, // ?\r | |
108 | 0x080, // ?\r | |
109 | 0x0,\r | |
110 | },\r | |
111 | //\r | |
112 | // Spare4\r | |
113 | //\r | |
114 | {\r | |
115 | 0x0, // limit 0\r | |
116 | 0x0, // base 0\r | |
117 | 0x0,\r | |
118 | 0x0, // present, ring 0, data, expand-up, writable\r | |
119 | 0x0, // page-granular, 32-bit\r | |
120 | 0x0,\r | |
121 | },\r | |
122 | //\r | |
123 | // Spare5\r | |
124 | //\r | |
125 | {\r | |
126 | 0x0, // limit 0\r | |
127 | 0x0, // base 0\r | |
128 | 0x0,\r | |
129 | 0x0, // present, ring 0, data, expand-up, writable\r | |
130 | 0x0, // page-granular, 32-bit\r | |
131 | 0x0,\r | |
132 | },\r | |
133 | };\r | |
134 | \r | |
135 | /**\r | |
136 | Initialize Global Descriptor Table.\r | |
137 | \r | |
138 | **/\r | |
139 | VOID\r | |
140 | InitLinuxDescriptorTables (\r | |
141 | VOID\r | |
142 | )\r | |
143 | {\r | |
144 | //\r | |
145 | // Allocate Runtime Data for the GDT\r | |
146 | //\r | |
147 | mGdt = AllocateRuntimePool (sizeof (GdtTemplate) + 8);\r | |
148 | ASSERT (mGdt != NULL);\r | |
149 | mGdt = ALIGN_POINTER (mGdt, 8);\r | |
150 | \r | |
151 | //\r | |
152 | // Initialize all GDT entries\r | |
153 | //\r | |
154 | CopyMem (mGdt, &GdtTemplate, sizeof (GdtTemplate));\r | |
155 | \r | |
156 | }\r | |
157 | \r | |
158 | /**\r | |
159 | Initialize Global Descriptor Table.\r | |
160 | \r | |
161 | **/\r | |
162 | VOID\r | |
163 | SetLinuxDescriptorTables (\r | |
164 | VOID\r | |
165 | )\r | |
166 | {\r | |
167 | IA32_DESCRIPTOR GdtPtr;\r | |
168 | IA32_DESCRIPTOR IdtPtr;\r | |
169 | \r | |
170 | //\r | |
171 | // Write GDT register\r | |
172 | //\r | |
173 | GdtPtr.Base = (UINT32)(UINTN)(VOID*) mGdt;\r | |
174 | GdtPtr.Limit = (UINT16) (sizeof (GdtTemplate) - 1);\r | |
175 | AsmWriteGdtr (&GdtPtr);\r | |
176 | \r | |
177 | IdtPtr.Base = (UINT32) 0;\r | |
178 | IdtPtr.Limit = (UINT16) 0;\r | |
179 | AsmWriteIdtr (&IdtPtr);\r | |
180 | }\r | |
181 | \r |