1 /* $OpenBSD: segments.h,v 1.14 2006/01/12 22:39:21 weingart Exp $ */
2 /* $NetBSD: segments.h,v 1.23 1996/02/01 22:31:03 mycroft Exp $ */
3
4 /*-
5 * Copyright (c) 1995 Charles M. Hannum. All rights reserved.
6 * Copyright (c) 1989, 1990 William F. Jolitz
7 * Copyright (c) 1990 The Regents of the University of California.
8 * All rights reserved.
9 *
10 * This code is derived from software contributed to Berkeley by
11 * William Jolitz.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)segments.h 7.1 (Berkeley) 5/9/91
38 */
39
40 /*
41 * 386 Segmentation Data Structures and definitions
42 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
43 */
44
45 #ifndef _I386_SEGMENTS_H_
46 #define _I386_SEGMENTS_H_
47
48 /*
49 * Selectors
50 */
51
52 #define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */
53 #define SEL_KPL 0 /* kernel privilege level */
54 #define SEL_UPL 3 /* user privilege level */
55 #define SEL_RPL 3 /* requester's privilege level mask */
56 #define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */
57 #define SEL_LDT 4 /* local descriptor table */
58 #define IDXSEL(s) (((s) >> 3) & 0x1fff) /* index of selector */
59 #define GSEL(s,r) (((s) << 3) | r) /* a global selector */
60 #define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */
61
62 #ifdef VM86
63 #define USERMODE(c, f) (ISPL(c) == SEL_UPL || ((f) & PSL_VM) != 0)
64 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL && ((f) & PSL_VM) == 0)
65 #else
66 #define USERMODE(c, f) (ISPL(c) == SEL_UPL)
67 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL)
68 #endif
69
70 #ifndef _LOCORE
71
72 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7
73 #pragma pack(1)
74 #endif
75
76 /*
77 * Memory and System segment descriptors
78 */
79 struct segment_descriptor {
80 unsigned sd_lolimit:16; /* segment extent (lsb) */
81 unsigned sd_lobase:24; /* segment base address (lsb) */
82 unsigned sd_type:5; /* segment type */
83 unsigned sd_dpl:2; /* segment descriptor priority level */
84 unsigned sd_p:1; /* segment descriptor present */
85 unsigned sd_hilimit:4; /* segment extent (msb) */
86 unsigned sd_xx:2; /* unused */
87 unsigned sd_def32:1; /* default 32 vs 16 bit size */
88 unsigned sd_gran:1; /* limit granularity (byte/page) */
89 unsigned sd_hibase:8; /* segment base address (msb) */
90 } __packed;
91
92 /*
93 * Gate descriptors (e.g. indirect descriptors)
94 */
95 struct gate_descriptor {
96 unsigned gd_looffset:16; /* gate offset (lsb) */
97 unsigned gd_selector:16; /* gate segment selector */
98 unsigned gd_stkcpy:5; /* number of stack wds to cpy */
99 unsigned gd_xx:3; /* unused */
100 unsigned gd_type:5; /* segment type */
101 unsigned gd_dpl:2; /* segment descriptor priority level */
102 unsigned gd_p:1; /* segment descriptor present */
103 unsigned gd_hioffset:16; /* gate offset (msb) */
104 } __packed;
105
106 /*
107 * Generic descriptor
108 */
109 union descriptor {
110 struct segment_descriptor sd;
111 struct gate_descriptor gd;
112 } __packed;
113
114 /*
115 * region descriptors, used to load gdt/idt tables before segments yet exist.
116 */
117 struct region_descriptor {
118 unsigned rd_limit:16; /* segment extent */
119 unsigned rd_base:32; /* base address */
120 } __packed;
121
122 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7
123 #pragma pack(4)
124 #endif
125
126 #ifdef _KERNEL
127 extern union descriptor *gdt, ldt[];
128 extern struct gate_descriptor idt_region[];
129 extern struct gate_descriptor *idt;
130
131 void setgate(struct gate_descriptor *, void *, int, int, int, int);
132 void setregion(struct region_descriptor *, void *, size_t);
133 void setsegment(struct segment_descriptor *, void *, size_t, int, int,
134 int, int);
135 void unsetgate(struct gate_descriptor *);
136 void cpu_init_idt(void);
137 void cpu_default_ldt(struct cpu_info *);
138 void cpu_alloc_ldt(struct cpu_info *);
139 void cpu_init_ldt(struct cpu_info *);
140
141 int idt_vec_alloc(int, int);
142 void idt_vec_set(int, void (*)(void));
143 void idt_vec_free(int);
144
145 #endif /* _KERNEL */
146
147 #endif /* !_LOCORE */
148
149 /* system segments and gate types */
150 #define SDT_SYSNULL 0 /* system null */
151 #define SDT_SYS286TSS 1 /* system 286 TSS available */
152 #define SDT_SYSLDT 2 /* system local descriptor table */
153 #define SDT_SYS286BSY 3 /* system 286 TSS busy */
154 #define SDT_SYS286CGT 4 /* system 286 call gate */
155 #define SDT_SYSTASKGT 5 /* system task gate */
156 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
157 #define SDT_SYS286TGT 7 /* system 286 trap gate */
158 #define SDT_SYSNULL2 8 /* system null again */
159 #define SDT_SYS386TSS 9 /* system 386 TSS available */
160 #define SDT_SYSNULL3 10 /* system null again */
161 #define SDT_SYS386BSY 11 /* system 386 TSS busy */
162 #define SDT_SYS386CGT 12 /* system 386 call gate */
163 #define SDT_SYSNULL4 13 /* system null again */
164 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
165 #define SDT_SYS386TGT 15 /* system 386 trap gate */
166
167 /* memory segment types */
168 #define SDT_MEMRO 16 /* memory read only */
169 #define SDT_MEMROA 17 /* memory read only accessed */
170 #define SDT_MEMRW 18 /* memory read write */
171 #define SDT_MEMRWA 19 /* memory read write accessed */
172 #define SDT_MEMROD 20 /* memory read only expand dwn limit */
173 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
174 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
175 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */
176 #define SDT_MEME 24 /* memory execute only */
177 #define SDT_MEMEA 25 /* memory execute only accessed */
178 #define SDT_MEMER 26 /* memory execute read */
179 #define SDT_MEMERA 27 /* memory execute read accessed */
180 #define SDT_MEMEC 28 /* memory execute only conforming */
181 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
182 #define SDT_MEMERC 30 /* memory execute read conforming */
183 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
184
185 /* is memory segment descriptor pointer ? */
186 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \
187 (s->d_type) <= SDT_MEMERAC)
188
189 /* is 286 gate descriptor pointer ? */
190 #define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \
191 (s->d_type) < SDT_SYS286TGT)
192
193 /* is 386 gate descriptor pointer ? */
194 #define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \
195 (s->d_type) < SDT_SYS386TGT)
196
197 /* is gate descriptor pointer ? */
198 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
199
200 /* is segment descriptor pointer ? */
201 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
202
203 /* is system segment descriptor pointer ? */
204 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
205
206 /*
207 * Segment Protection Exception code bits
208 */
209 #define SEGEX_EXT 0x01 /* recursive or externally induced */
210 #define SEGEX_IDT 0x02 /* interrupt descriptor table */
211 #define SEGEX_TI 0x04 /* local descriptor table */
212
213 /*
214 * Entries in the Interrupt Descriptor Table (IDT)
215 */
216 #define NIDT 256
217 #define NRSVIDT 32 /* reserved entries for cpu exceptions */
218
219 /*
220 * Entries in the Global Descriptor Table (GDT)
221 */
222 #define GNULL_SEL 0 /* Null descriptor */
223 #define GCODE_SEL 1 /* Kernel code descriptor */
224 #define GDATA_SEL 2 /* Kernel data descriptor */
225 #define GLDT_SEL 3 /* Default LDT descriptor */
226 #define GUCODE1_SEL 4 /* User code descriptor */
227 #define GUCODE_SEL 5 /* User code descriptor (a stack short) */
228 #define GUDATA_SEL 6 /* User data descriptor */
229 #define GAPM32CODE_SEL 7 /* 32 bit APM code descriptor */
230 #define GAPM16CODE_SEL 8 /* 16 bit APM code descriptor */
231 #define GAPMDATA_SEL 9 /* APM data descriptor */
232 #define GICODE_SEL 10 /* Interrupt code descriptor (same as Kernel code) */
233 #define GCPU_SEL 11 /* per-CPU segment */
234 #define NGDT 12
235
236 /*
237 * Entries in the Local Descriptor Table (LDT)
238 */
239 #define LSYS5CALLS_SEL 0 /* iBCS system call gate */
240 #define LSYS5SIGR_SEL 1 /* iBCS sigreturn gate */
241 #define LUCODE1_SEL 2 /* User code descriptor */
242 #define LUCODE_SEL 3 /* User code descriptor (a stack short) */
243 #define LUDATA_SEL 4 /* User data descriptor */
244 #define LBSDICALLS_SEL 16 /* BSDI system call gate */
245 #define NLDT 17
246
247 #endif /* _I386_SEGMENTS_H_ */