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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* $OpenBSD: segments.h,v 1.26 2018/07/09 19:20:30 guenther Exp $ */
/* $NetBSD: segments.h,v 1.23 1996/02/01 22:31:03 mycroft Exp $ */
/*-
* Copyright (c) 1995 Charles M. Hannum. All rights reserved.
* Copyright (c) 1989, 1990 William F. Jolitz
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
* @(#)segments.h 7.1 (Berkeley) 5/9/91
*/
/*
* 386 Segmentation Data Structures and definitions
* William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
*/
#ifndef _MACHINE_SEGMENTS_H_
#define _MACHINE_SEGMENTS_H_
/*
* Selectors
*/
#define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */
#define SEL_KPL 0 /* kernel privilege level */
#define SEL_UPL 3 /* user privilege level */
#define SEL_RPL 3 /* requester's privilege level mask */
#define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */
#define SEL_LDT 4 /* local descriptor table */
#define IDXSEL(s) (((s) >> 3) & 0x1fff) /* index of selector */
#define GSEL(s,r) (((s) << 3) | r) /* a global selector */
#define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */
#define USERMODE(c, f) (ISPL(c) == SEL_UPL)
#define KERNELMODE(c, f) (ISPL(c) == SEL_KPL)
#ifndef _LOCORE
/*
* Memory and System segment descriptors
*/
struct segment_descriptor {
unsigned sd_lolimit:16; /* segment extent (lsb) */
unsigned sd_lobase:24; /* segment base address (lsb) */
unsigned sd_type:5; /* segment type */
unsigned sd_dpl:2; /* segment descriptor priority level */
unsigned sd_p:1; /* segment descriptor present */
unsigned sd_hilimit:4; /* segment extent (msb) */
unsigned sd_xx:2; /* unused */
unsigned sd_def32:1; /* default 32 vs 16 bit size */
unsigned sd_gran:1; /* limit granularity (byte/page) */
unsigned sd_hibase:8; /* segment base address (msb) */
} __packed;
/*
* Gate descriptors (e.g. indirect descriptors)
*/
struct gate_descriptor {
unsigned gd_looffset:16; /* gate offset (lsb) */
unsigned gd_selector:16; /* gate segment selector */
unsigned gd_stkcpy:5; /* number of stack wds to cpy */
unsigned gd_xx:3; /* unused */
unsigned gd_type:5; /* segment type */
unsigned gd_dpl:2; /* segment descriptor priority level */
unsigned gd_p:1; /* segment descriptor present */
unsigned gd_hioffset:16; /* gate offset (msb) */
} __packed;
/*
* Generic descriptor
*/
union descriptor {
struct segment_descriptor sd;
struct gate_descriptor gd;
} __packed;
/*
* region descriptors, used to load gdt/idt tables before segments yet exist.
*/
struct region_descriptor {
unsigned rd_limit:16; /* segment extent */
unsigned rd_base:32; /* base address */
} __packed;
#ifdef _KERNEL
extern union descriptor *gdt;
extern struct gate_descriptor idt_region[];
extern struct gate_descriptor *idt;
void setgate(struct gate_descriptor *, void *, int, int, int, int);
void setregion(struct region_descriptor *, void *, size_t);
void setsegment(struct segment_descriptor *, void *, size_t, int, int,
int, int);
void unsetgate(struct gate_descriptor *);
void cpu_init_idt(void);
int idt_vec_alloc(int, int);
void idt_vec_set(int, void (*)(void));
void idt_vec_free(int);
#endif /* _KERNEL */
#endif /* !_LOCORE */
/* system segments and gate types */
#define SDT_SYSNULL 0 /* system null */
#define SDT_SYS286TSS 1 /* system 286 TSS available */
#define SDT_SYSLDT 2 /* system local descriptor table */
#define SDT_SYS286BSY 3 /* system 286 TSS busy */
#define SDT_SYS286CGT 4 /* system 286 call gate */
#define SDT_SYSTASKGT 5 /* system task gate */
#define SDT_SYS286IGT 6 /* system 286 interrupt gate */
#define SDT_SYS286TGT 7 /* system 286 trap gate */
#define SDT_SYSNULL2 8 /* system null again */
#define SDT_SYS386TSS 9 /* system 386 TSS available */
#define SDT_SYSNULL3 10 /* system null again */
#define SDT_SYS386BSY 11 /* system 386 TSS busy */
#define SDT_SYS386CGT 12 /* system 386 call gate */
#define SDT_SYSNULL4 13 /* system null again */
#define SDT_SYS386IGT 14 /* system 386 interrupt gate */
#define SDT_SYS386TGT 15 /* system 386 trap gate */
/* memory segment types */
#define SDT_MEMRO 16 /* memory read only */
#define SDT_MEMROA 17 /* memory read only accessed */
#define SDT_MEMRW 18 /* memory read write */
#define SDT_MEMRWA 19 /* memory read write accessed */
#define SDT_MEMROD 20 /* memory read only expand dwn limit */
#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
#define SDT_MEMRWD 22 /* memory read write expand dwn limit */
#define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */
#define SDT_MEME 24 /* memory execute only */
#define SDT_MEMEA 25 /* memory execute only accessed */
#define SDT_MEMER 26 /* memory execute read */
#define SDT_MEMERA 27 /* memory execute read accessed */
#define SDT_MEMEC 28 /* memory execute only conforming */
#define SDT_MEMEAC 29 /* memory execute only accessed conforming */
#define SDT_MEMERC 30 /* memory execute read conforming */
#define SDT_MEMERAC 31 /* memory execute read accessed conforming */
/* is memory segment descriptor pointer ? */
#define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \
(s->d_type) <= SDT_MEMERAC)
/* is 286 gate descriptor pointer ? */
#define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \
(s->d_type) < SDT_SYS286TGT)
/* is 386 gate descriptor pointer ? */
#define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \
(s->d_type) < SDT_SYS386TGT)
/* is gate descriptor pointer ? */
#define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
/* is segment descriptor pointer ? */
#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
/* is system segment descriptor pointer ? */
#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
/*
* Segment Protection Exception code bits
*/
#define SEGEX_EXT 0x01 /* recursive or externally induced */
#define SEGEX_IDT 0x02 /* interrupt descriptor table */
#define SEGEX_TI 0x04 /* local descriptor table */
/*
* Entries in the Interrupt Descriptor Table (IDT)
*/
#define NIDT 256
#define NRSVIDT 32 /* reserved entries for cpu exceptions */
/*
* Entries in the Global Descriptor Table (GDT)
*/
#define GNULL_SEL 0 /* Null descriptor */
#define GCODE_SEL 1 /* Kernel code descriptor */
#define GDATA_SEL 2 /* Kernel data descriptor */
#define GLDT_SEL 3 /* Default LDT descriptor (UNUSED) */
#define GCPU_SEL 4 /* per-CPU segment */
#define GUCODE_SEL 5 /* User code descriptor (a stack short) */
#define GUDATA_SEL 6 /* User data descriptor */
#define GAPM32CODE_SEL 7 /* 32 bit APM code descriptor */
#define GAPM16CODE_SEL 8 /* 16 bit APM code descriptor */
#define GAPMDATA_SEL 9 /* APM data descriptor */
#define GICODE_SEL 10 /* Interrupt code descriptor (same as Kernel code) */
#define GUFS_SEL 11 /* User per-thread (%fs) descriptor */
#define GUGS_SEL 12 /* User per-thread (%gs) descriptor */
#define GTSS_SEL 13 /* common TSS */
#define GNMITSS_SEL 14 /* NMI TSS */
#define GBIOS32_SEL 15 /* spare slot for 32 bit BIOS calls */
#define NGDT 16
#define GDT_SIZE (NGDT << 3)
#endif /* _MACHINE_SEGMENTS_H_ */
|
