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1.1 root 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: * @(#)segments.h 7.1 (Berkeley) 5/9/91
38: */
39:
40: /*
41: * 386 Segmentation Data Structures and definitions
42: * William F. Jolitz ([email protected]) 6/20/1989
43: */
44:
45: /*
46: * Selectors
47: */
48:
49: #define ISPL(s) ((s)&3) /* what is the priority level of a selector */
50: #define SEL_KPL 0 /* kernel priority level */
51: #define SEL_UPL 3 /* user priority level */
52: #define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */
53: #define SEL_LDT 4 /* local descriptor table */
54: #define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */
55: #define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */
56: #define GSEL(s,r) (((s)<<3) | r) /* a global selector */
57:
58: /*
59: * Memory and System segment descriptors
60: */
61: struct segment_descriptor {
62: unsigned sd_lolimit:16 ; /* segment extent (lsb) */
63: unsigned sd_lobase:24 ; /* segment base address (lsb) */
64: unsigned sd_type:5 ; /* segment type */
65: unsigned sd_dpl:2 ; /* segment descriptor priority level */
66: unsigned sd_p:1 ; /* segment descriptor present */
67: unsigned sd_hilimit:4 ; /* segment extent (msb) */
68: unsigned sd_xx:2 ; /* unused */
69: unsigned sd_def32:1 ; /* default 32 vs 16 bit size */
70: unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/
71: unsigned sd_hibase:8 ; /* segment base address (msb) */
72: } ;
73:
74: /*
75: * Gate descriptors (e.g. indirect descriptors)
76: */
77: struct gate_descriptor {
78: unsigned gd_looffset:16 ; /* gate offset (lsb) */
79: unsigned gd_selector:16 ; /* gate segment selector */
80: unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */
81: unsigned gd_xx:3 ; /* unused */
82: unsigned gd_type:5 ; /* segment type */
83: unsigned gd_dpl:2 ; /* segment descriptor priority level */
84: unsigned gd_p:1 ; /* segment descriptor present */
85: unsigned gd_hioffset:16 ; /* gate offset (msb) */
86: } ;
87:
88: /*
89: * Generic descriptor
90: */
91: union descriptor {
92: struct segment_descriptor sd;
93: struct gate_descriptor gd;
94: };
95: #define d_type gd.gd_type
96:
97: /* system segments and gate types */
98: #define SDT_SYSNULL 0 /* system null */
99: #define SDT_SYS286TSS 1 /* system 286 TSS available */
100: #define SDT_SYSLDT 2 /* system local descriptor table */
101: #define SDT_SYS286BSY 3 /* system 286 TSS busy */
102: #define SDT_SYS286CGT 4 /* system 286 call gate */
103: #define SDT_SYSTASKGT 5 /* system task gate */
104: #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
105: #define SDT_SYS286TGT 7 /* system 286 trap gate */
106: #define SDT_SYSNULL2 8 /* system null again */
107: #define SDT_SYS386TSS 9 /* system 386 TSS available */
108: #define SDT_SYSNULL3 10 /* system null again */
109: #define SDT_SYS386BSY 11 /* system 386 TSS busy */
110: #define SDT_SYS386CGT 12 /* system 386 call gate */
111: #define SDT_SYSNULL4 13 /* system null again */
112: #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
113: #define SDT_SYS386TGT 15 /* system 386 trap gate */
114:
115: /* memory segment types */
116: #define SDT_MEMRO 16 /* memory read only */
117: #define SDT_MEMROA 17 /* memory read only accessed */
118: #define SDT_MEMRW 18 /* memory read write */
119: #define SDT_MEMRWA 19 /* memory read write accessed */
120: #define SDT_MEMROD 20 /* memory read only expand dwn limit */
121: #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
122: #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
123: #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */
124: #define SDT_MEME 24 /* memory execute only */
125: #define SDT_MEMEA 25 /* memory execute only accessed */
126: #define SDT_MEMER 26 /* memory execute read */
127: #define SDT_MEMERA 27 /* memory execute read accessed */
128: #define SDT_MEMEC 28 /* memory execute only conforming */
129: #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
130: #define SDT_MEMERC 30 /* memory execute read conforming */
131: #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
132:
133: /* is memory segment descriptor pointer ? */
134: #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC)
135:
136: /* is 286 gate descriptor pointer ? */
137: #define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \
138: && (s->d_type) < SDT_SYS286TGT))
139:
140: /* is 386 gate descriptor pointer ? */
141: #define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \
142: && (s->d_type) < SDT_SYS386TGT))
143:
144: /* is gate descriptor pointer ? */
145: #define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
146:
147: /* is segment descriptor pointer ? */
148: #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
149:
150: /* is system segment descriptor pointer ? */
151: #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
152:
153: /*
154: * Software definitions are in this convenient format,
155: * which are translated into inconvenient segment descriptors
156: * when needed to be used by the 386 hardware
157: */
158:
159: struct soft_segment_descriptor {
160: unsigned ssd_base ; /* segment base address */
161: unsigned ssd_limit ; /* segment extent */
162: unsigned ssd_type:5 ; /* segment type */
163: unsigned ssd_dpl:2 ; /* segment descriptor priority level */
164: unsigned ssd_p:1 ; /* segment descriptor present */
165: unsigned ssd_xx:4 ; /* unused */
166: unsigned ssd_xx1:2 ; /* unused */
167: unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */
168: unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/
169: };
170:
171: extern ssdtosd() ; /* to decode a ssd */
172: extern sdtossd() ; /* to encode a sd */
173:
174: /*
175: * region descriptors, used to load gdt/idt tables before segments yet exist
176: */
177: struct region_descriptor {
178: unsigned rd_limit:16 ; /* segment extent */
179: char *rd_base; /* base address */
180: };
181:
182: /*
183: * Segment Protection Exception code bits
184: */
185:
186: #define SEGEX_EXT 0x01 /* recursive or externally induced */
187: #define SEGEX_IDT 0x02 /* interrupt descriptor table */
188: #define SEGEX_TI 0x04 /* local descriptor table */
189: /* other bits are affected descriptor index */
190: #define SEGEX_IDX(s) ((s)>>3)&0x1fff)
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