1 /*-
2 * Copyright (c) 1989, 1990 William F. Jolitz
3 * Copyright (c) 1990 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * William Jolitz.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. 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 * from: @(#)segments.h 7.1 (Berkeley) 5/9/91
38 * $FreeBSD$
39 */
40
41 #ifndef _MACHINE_SEGMENTS_H_
42 #define _MACHINE_SEGMENTS_H_
43
44 /*
45 * 386 Segmentation Data Structures and definitions
46 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
47 */
48
49 /*
50 * Selectors
51 */
52
53 #define ISPL(s) ((s)&3) /* what is the priority level of a selector */
54 #define SEL_KPL 0 /* kernel priority level */
55 #define SEL_UPL 3 /* user priority level */
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 LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */
60 #define GSEL(s,r) (((s)<<3) | r) /* a global selector */
61
62 /*
63 * Memory and System segment descriptors
64 */
65 struct segment_descriptor {
66 unsigned sd_lolimit:16 ; /* segment extent (lsb) */
67 unsigned sd_lobase:24 __attribute__ ((packed));
68 /* segment base address (lsb) */
69 unsigned sd_type:5 ; /* segment type */
70 unsigned sd_dpl:2 ; /* segment descriptor priority level */
71 unsigned sd_p:1 ; /* segment descriptor present */
72 unsigned sd_hilimit:4 ; /* segment extent (msb) */
73 unsigned sd_xx:2 ; /* unused */
74 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */
75 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/
76 unsigned sd_hibase:8 ; /* segment base address (msb) */
77 } ;
78
79 /*
80 * Gate descriptors (e.g. indirect descriptors)
81 */
82 struct gate_descriptor {
83 unsigned gd_looffset:16 ; /* gate offset (lsb) */
84 unsigned gd_selector:16 ; /* gate segment selector */
85 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */
86 unsigned gd_xx:3 ; /* unused */
87 unsigned gd_type:5 ; /* segment type */
88 unsigned gd_dpl:2 ; /* segment descriptor priority level */
89 unsigned gd_p:1 ; /* segment descriptor present */
90 unsigned gd_hioffset:16 ; /* gate offset (msb) */
91 } ;
92
93 /*
94 * Generic descriptor
95 */
96 union descriptor {
97 struct segment_descriptor sd;
98 struct gate_descriptor gd;
99 };
100
101 /* system segments and gate types */
102 #define SDT_SYSNULL 0 /* system null */
103 #define SDT_SYS286TSS 1 /* system 286 TSS available */
104 #define SDT_SYSLDT 2 /* system local descriptor table */
105 #define SDT_SYS286BSY 3 /* system 286 TSS busy */
106 #define SDT_SYS286CGT 4 /* system 286 call gate */
107 #define SDT_SYSTASKGT 5 /* system task gate */
108 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
109 #define SDT_SYS286TGT 7 /* system 286 trap gate */
110 #define SDT_SYSNULL2 8 /* system null again */
111 #define SDT_SYS386TSS 9 /* system 386 TSS available */
112 #define SDT_SYSNULL3 10 /* system null again */
113 #define SDT_SYS386BSY 11 /* system 386 TSS busy */
114 #define SDT_SYS386CGT 12 /* system 386 call gate */
115 #define SDT_SYSNULL4 13 /* system null again */
116 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
117 #define SDT_SYS386TGT 15 /* system 386 trap gate */
118
119 /* memory segment types */
120 #define SDT_MEMRO 16 /* memory read only */
121 #define SDT_MEMROA 17 /* memory read only accessed */
122 #define SDT_MEMRW 18 /* memory read write */
123 #define SDT_MEMRWA 19 /* memory read write accessed */
124 #define SDT_MEMROD 20 /* memory read only expand dwn limit */
125 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
126 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
127 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
128 #define SDT_MEME 24 /* memory execute only */
129 #define SDT_MEMEA 25 /* memory execute only accessed */
130 #define SDT_MEMER 26 /* memory execute read */
131 #define SDT_MEMERA 27 /* memory execute read accessed */
132 #define SDT_MEMEC 28 /* memory execute only conforming */
133 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
134 #define SDT_MEMERC 30 /* memory execute read conforming */
135 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
136
137 /* is memory segment descriptor pointer ? */
138 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC)
139
140 /* is 286 gate descriptor pointer ? */
141 #define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \
142 && (s->d_type) < SDT_SYS286TGT))
143
144 /* is 386 gate descriptor pointer ? */
145 #define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \
146 && (s->d_type) < SDT_SYS386TGT))
147
148 /* is gate descriptor pointer ? */
149 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
150
151 /* is segment descriptor pointer ? */
152 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
153
154 /* is system segment descriptor pointer ? */
155 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
156
157 /*
158 * Software definitions are in this convenient format,
159 * which are translated into inconvenient segment descriptors
160 * when needed to be used by the 386 hardware
161 */
162
163 struct soft_segment_descriptor {
164 unsigned ssd_base ; /* segment base address */
165 unsigned ssd_limit ; /* segment extent */
166 unsigned ssd_type:5 ; /* segment type */
167 unsigned ssd_dpl:2 ; /* segment descriptor priority level */
168 unsigned ssd_p:1 ; /* segment descriptor present */
169 unsigned ssd_xx:4 ; /* unused */
170 unsigned ssd_xx1:2 ; /* unused */
171 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */
172 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/
173 };
174
175 /*
176 * region descriptors, used to load gdt/idt tables before segments yet exist.
177 */
178 struct region_descriptor {
179 unsigned rd_limit:16; /* segment extent */
180 unsigned rd_base:32 __attribute__ ((packed)); /* base address */
181 };
182
183 /*
184 * Segment Protection Exception code bits
185 */
186
187 #define SEGEX_EXT 0x01 /* recursive or externally induced */
188 #define SEGEX_IDT 0x02 /* interrupt descriptor table */
189 #define SEGEX_TI 0x04 /* local descriptor table */
190 /* other bits are affected descriptor index */
191 #define SEGEX_IDX(s) ((s)>>3)&0x1fff)
192
193 /*
194 * Size of IDT table
195 */
196
197 #if defined(SMP) || defined(APIC_IO)
198 #define NIDT 256 /* we use them all */
199 #else
200 #define NIDT 129 /* 32 reserved, 16 h/w, 0 s/w, linux's 0x80 */
201 #endif /* SMP || APIC_IO */
202 #define NRSVIDT 32 /* reserved entries for cpu exceptions */
203
204 /*
205 * Entries in the Global Descriptor Table (GDT)
206 */
207 #define GNULL_SEL 0 /* Null Descriptor */
208 #define GCODE_SEL 1 /* Kernel Code Descriptor */
209 #define GDATA_SEL 2 /* Kernel Data Descriptor */
210 #define GLDT_SEL 3 /* LDT - eventually one per process */
211 #define GTGATE_SEL 4 /* Process task switch gate */
212 #define GPANIC_SEL 5 /* Task state to consider panic from */
213 #define GPROC0_SEL 6 /* Task state process slot zero and up */
214 #define GUSERLDT_SEL 7 /* User LDT */
215 #define GAPMCODE32_SEL 8 /* APM BIOS 32-bit interface (32bit Code) */
216 #define GAPMCODE16_SEL 9 /* APM BIOS 32-bit interface (16bit Code) */
217 #define GAPMDATA_SEL 10 /* APM BIOS 32-bit interface (Data) */
218
219 #ifdef BDE_DEBUGGER
220 #define NGDT 18 /* some of 11-17 are reserved for debugger */
221 #else
222 #define NGDT (GAPMDATA_SEL + 1)
223 #endif
224
225 /*
226 * Entries in the Local Descriptor Table (LDT)
227 */
228 #define LSYS5CALLS_SEL 0 /* forced by intel BCS */
229 #define LSYS5SIGR_SEL 1
230 #define L43BSDCALLS_SEL 2 /* notyet */
231 #define LUCODE_SEL 3
232 #define LUDATA_SEL 4
233 /* separate stack, es,fs,gs sels ? */
234 /* #define LPOSIXCALLS_SEL 5*/ /* notyet */
235 #define LBSDICALLS_SEL 16 /* BSDI system call gate */
236 #define NLDT (LBSDICALLS_SEL + 1)
237
238 #ifdef KERNEL
239 extern int currentldt;
240 extern int _default_ldt;
241 extern union descriptor gdt[];
242 extern struct soft_segment_descriptor gdt_segs[];
243 extern struct gate_descriptor idt[NIDT];
244 extern union descriptor ldt[NLDT];
245
246 void lgdt __P((struct region_descriptor *rdp));
247 void lidt __P((struct region_descriptor *rdp));
248 void lldt __P((u_short sel));
249 void sdtossd __P((struct segment_descriptor *sdp,
250 struct soft_segment_descriptor *ssdp));
251 void ssdtosd __P((struct soft_segment_descriptor *ssdp,
252 struct segment_descriptor *sdp));
253 #endif /* KERNEL */
254
255 #endif /* !_MACHINE_SEGMENTS_H_ */
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