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: releng/5.1/sys/i386/include/segments.h 109994 2003-01-28 19:05:44Z jake $
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 __packed; /* segment base address (lsb) */
68 unsigned sd_type:5 ; /* segment type */
69 unsigned sd_dpl:2 ; /* segment descriptor priority level */
70 unsigned sd_p:1 ; /* segment descriptor present */
71 unsigned sd_hilimit:4 ; /* segment extent (msb) */
72 unsigned sd_xx:2 ; /* unused */
73 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */
74 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/
75 unsigned sd_hibase:8 ; /* segment base address (msb) */
76 } ;
77
78 /*
79 * Gate descriptors (e.g. indirect descriptors)
80 */
81 struct gate_descriptor {
82 unsigned gd_looffset:16 ; /* gate offset (lsb) */
83 unsigned gd_selector:16 ; /* gate segment selector */
84 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */
85 unsigned gd_xx:3 ; /* unused */
86 unsigned gd_type:5 ; /* segment type */
87 unsigned gd_dpl:2 ; /* segment descriptor priority level */
88 unsigned gd_p:1 ; /* segment descriptor present */
89 unsigned gd_hioffset:16 ; /* gate offset (msb) */
90 } ;
91
92 /*
93 * Generic descriptor
94 */
95 union descriptor {
96 struct segment_descriptor sd;
97 struct gate_descriptor gd;
98 };
99
100 /* system segments and gate types */
101 #define SDT_SYSNULL 0 /* system null */
102 #define SDT_SYS286TSS 1 /* system 286 TSS available */
103 #define SDT_SYSLDT 2 /* system local descriptor table */
104 #define SDT_SYS286BSY 3 /* system 286 TSS busy */
105 #define SDT_SYS286CGT 4 /* system 286 call gate */
106 #define SDT_SYSTASKGT 5 /* system task gate */
107 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
108 #define SDT_SYS286TGT 7 /* system 286 trap gate */
109 #define SDT_SYSNULL2 8 /* system null again */
110 #define SDT_SYS386TSS 9 /* system 386 TSS available */
111 #define SDT_SYSNULL3 10 /* system null again */
112 #define SDT_SYS386BSY 11 /* system 386 TSS busy */
113 #define SDT_SYS386CGT 12 /* system 386 call gate */
114 #define SDT_SYSNULL4 13 /* system null again */
115 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
116 #define SDT_SYS386TGT 15 /* system 386 trap gate */
117
118 /* memory segment types */
119 #define SDT_MEMRO 16 /* memory read only */
120 #define SDT_MEMROA 17 /* memory read only accessed */
121 #define SDT_MEMRW 18 /* memory read write */
122 #define SDT_MEMRWA 19 /* memory read write accessed */
123 #define SDT_MEMROD 20 /* memory read only expand dwn limit */
124 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
125 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
126 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
127 #define SDT_MEME 24 /* memory execute only */
128 #define SDT_MEMEA 25 /* memory execute only accessed */
129 #define SDT_MEMER 26 /* memory execute read */
130 #define SDT_MEMERA 27 /* memory execute read accessed */
131 #define SDT_MEMEC 28 /* memory execute only conforming */
132 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
133 #define SDT_MEMERC 30 /* memory execute read conforming */
134 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
135
136 /*
137 * Software definitions are in this convenient format,
138 * which are translated into inconvenient segment descriptors
139 * when needed to be used by the 386 hardware
140 */
141
142 struct soft_segment_descriptor {
143 unsigned ssd_base ; /* segment base address */
144 unsigned ssd_limit ; /* segment extent */
145 unsigned ssd_type:5 ; /* segment type */
146 unsigned ssd_dpl:2 ; /* segment descriptor priority level */
147 unsigned ssd_p:1 ; /* segment descriptor present */
148 unsigned ssd_xx:4 ; /* unused */
149 unsigned ssd_xx1:2 ; /* unused */
150 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */
151 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/
152 };
153
154 /*
155 * region descriptors, used to load gdt/idt tables before segments yet exist.
156 */
157 struct region_descriptor {
158 unsigned rd_limit:16; /* segment extent */
159 unsigned rd_base:32 __packed; /* base address */
160 };
161
162 /*
163 * Segment Protection Exception code bits
164 */
165
166 #define SEGEX_EXT 0x01 /* recursive or externally induced */
167 #define SEGEX_IDT 0x02 /* interrupt descriptor table */
168 #define SEGEX_TI 0x04 /* local descriptor table */
169 /* other bits are affected descriptor index */
170 #define SEGEX_IDX(s) (((s)>>3)&0x1fff)
171
172 /*
173 * Size of IDT table
174 */
175
176 #if defined(SMP) || defined(APIC_IO)
177 #define NIDT 256 /* we use them all */
178 #else
179 #define NIDT 129 /* 32 reserved, 16 h/w, 0 s/w, linux's 0x80 */
180 #endif /* SMP || APIC_IO */
181 #define NRSVIDT 32 /* reserved entries for cpu exceptions */
182
183 /*
184 * Entries in the Global Descriptor Table (GDT)
185 */
186 #define GNULL_SEL 0 /* Null Descriptor */
187 #define GCODE_SEL 1 /* Kernel Code Descriptor */
188 #define GDATA_SEL 2 /* Kernel Data Descriptor */
189 #define GPRIV_SEL 3 /* SMP Per-Processor Private Data */
190 #define GPROC0_SEL 4 /* Task state process slot zero and up */
191 #define GLDT_SEL 5 /* LDT - eventually one per process */
192 #define GUSERLDT_SEL 6 /* User LDT */
193 #define GTGATE_SEL 7 /* Process task switch gate */
194 #define GBIOSLOWMEM_SEL 8 /* BIOS low memory access (must be entry 8) */
195 #define GPANIC_SEL 9 /* Task state to consider panic from */
196 #define GBIOSCODE32_SEL 10 /* BIOS interface (32bit Code) */
197 #define GBIOSCODE16_SEL 11 /* BIOS interface (16bit Code) */
198 #define GBIOSDATA_SEL 12 /* BIOS interface (Data) */
199 #define GBIOSUTIL_SEL 13 /* BIOS interface (Utility) */
200 #define GBIOSARGS_SEL 14 /* BIOS interface (Arguments) */
201
202 #define NGDT 15
203
204 /*
205 * Entries in the Local Descriptor Table (LDT)
206 */
207 #define LSYS5CALLS_SEL 0 /* forced by intel BCS */
208 #define LSYS5SIGR_SEL 1
209 #define L43BSDCALLS_SEL 2 /* notyet */
210 #define LUCODE_SEL 3
211 #define LSOL26CALLS_SEL 4 /* Solaris >= 2.6 system call gate */
212 #define LUDATA_SEL 5
213 /* separate stack, es,fs,gs sels ? */
214 /* #define LPOSIXCALLS_SEL 5*/ /* notyet */
215 #define LBSDICALLS_SEL 16 /* BSDI system call gate */
216 #define NLDT (LBSDICALLS_SEL + 1)
217
218 #ifdef _KERNEL
219 extern int _default_ldt;
220 extern union descriptor gdt[];
221 extern struct soft_segment_descriptor gdt_segs[];
222 extern struct gate_descriptor *idt;
223 extern union descriptor ldt[NLDT];
224
225 void lgdt(struct region_descriptor *rdp);
226 void sdtossd(struct segment_descriptor *sdp,
227 struct soft_segment_descriptor *ssdp);
228 void ssdtosd(struct soft_segment_descriptor *ssdp,
229 struct segment_descriptor *sdp);
230 #endif /* _KERNEL */
231
232 #endif /* !_MACHINE_SEGMENTS_H_ */
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