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1/*
2 * Copyright (c) 2004 Security Architects Corporation. All rights reserved.
3 *
4 * Module Name:
5 *
6 * i386.h
7 *
8 * Abstract:
9 *
10 * This module definies various types and macros used by x86 specific routines.
11 *
12 * Author:
13 *
14 * Eugene Tsyrklevich 24-Mar-2004
15 *
16 * Revision History:
17 *
18 * None.
19 */
20
21
22#ifndef __I386_H__
23#define __I386_H__
24
25
26
27typedef struct _KTSS {
28
29 USHORT Backlink;
30 USHORT Reserved0;
31
32 ULONG Esp0;
33 USHORT Ss0;
34 USHORT Reserved1;
35
36 ULONG NotUsed1[4];
37
38 ULONG CR3;
39
40 ULONG Eip;
41
42 ULONG NotUsed2[9];
43
44 USHORT Es;
45 USHORT Reserved2;
46
47 USHORT Cs;
48 USHORT Reserved3;
49
50 USHORT Ss;
51 USHORT Reserved4;
52
53 USHORT Ds;
54 USHORT Reserved5;
55
56 USHORT Fs;
57 USHORT Reserved6;
58
59 USHORT Gs;
60 USHORT Reserved7;
61
62 USHORT LDT;
63 USHORT Reserved8;
64
65 USHORT Flags;
66
67 USHORT IoMapBase;
68
69 /* IO/INT MAPS go here */
70
71} KTSS, *PKTSS;
72
73
74typedef struct _KGDTENTRY {
75 USHORT LimitLow;
76 USHORT BaseLow;
77 union {
78 struct {
79 UCHAR BaseMid;
80 UCHAR Flags1; // Declare as bytes to avoid alignment
81 UCHAR Flags2; // Problems.
82 UCHAR BaseHi;
83 } Bytes;
84 struct {
85 ULONG BaseMid : 8;
86 ULONG Type : 5;
87 ULONG Dpl : 2;
88 ULONG Pres : 1;
89 ULONG LimitHi : 4;
90 ULONG Sys : 1;
91 ULONG Reserved_0 : 1;
92 ULONG Default_Big : 1;
93 ULONG Granularity : 1;
94 ULONG BaseHi : 8;
95 } Bits;
96 } HighWord;
97} KGDTENTRY, *PKGDTENTRY;
98
99
100#define INTERRUPTS_OFF() _asm { cli }
101#define INTERRUPTS_ON() _asm { sti }
102
103
104/*
105 * WP Write Protect (bit 16 of CR0).
106 * Inhibits supervisor-level procedures from writing into user-level read-only pages when set;
107 * allows supervisor-level procedures to write into user-level read-only pages when clear.
108 * This flag facilitates implementation of the copyon-write method of creating a new process (forking)
109 * used by operating systems such as UNIX.
110 */
111
112#define CR0_WP_BIT (0x10000)
113
114#define MEMORY_PROTECTION_OFF() \
115 __asm mov eax, cr0 \
116 __asm and eax, NOT CR0_WP_BIT \
117 __asm mov cr0, eax
118
119#define MEMORY_PROTECTION_ON() \
120 __asm mov eax, cr0 \
121 __asm or eax, CR0_WP_BIT \
122 __asm mov cr0, eax
123
124
125
126/* x86 opcodes */
127
128#define X86_OPCODE_PUSH 0x68
129#define X86_OPCODE_MOV_EAX_VALUE 0xB8
130
131#define X86_OPCODE_CALL_EAX 0xD0FF
132#define X86_OPCODE_JMP_DWORD_PTR 0x25FF
133
134
135
136/*
137 * Save a value on stack:
138 *
139 * push PushValue
140 */
141
142#define ASM_PUSH(CodeAddress, PushValue) \
143 * (PCHAR) (CodeAddress)++ = X86_OPCODE_PUSH; \
144 * (PULONG) (CodeAddress) = (ULONG) (PushValue); \
145 (PCHAR) (CodeAddress) += 4;
146
147/*
148 * Call a function:
149 *
150 * mov eax, FunctionAddress
151 * call eax
152 */
153
154#define ASM_CALL(CodeAddress, FunctionAddress) \
155 * (PCHAR) (CodeAddress)++ = X86_OPCODE_MOV_EAX_VALUE; \
156 * (PULONG) (CodeAddress) = (ULONG) (FunctionAddress); \
157 (PCHAR) (CodeAddress) += 4; \
158 * ((PUSHORT) (CodeAddress))++ = X86_OPCODE_CALL_EAX;
159
160
161/*
162 * Jump to a specified address:
163 *
164 * jmp dword ptr [next_4_bytes]
165 * *(next_4_bytes) = address
166 *
167 * NOTE XXX: this should be converted to a direct jmp address but i
168 * can't figure out how that instruction is encoded (opcode 0xE9)
169 */
170
171#define ASM_JMP(CodeAddress, JmpAddress) \
172 * ((PUSHORT) (CodeAddress))++ = X86_OPCODE_JMP_DWORD_PTR; \
173 * (PULONG) (CodeAddress) = (ULONG) (JmpAddress); \
174 (PCHAR) (CodeAddress) += 4;
175
176
177extern ULONG SystemAddressStart;
178
179
180BOOLEAN InitI386();
181VOID VerifyUserReturnAddress();
182
183
184#endif /* __I386_H__ */ \ No newline at end of file