segments.h revision 621
1169689Skan/*-
2169689Skan * Copyright (c) 1989, 1990 William F. Jolitz
3169689Skan * Copyright (c) 1990 The Regents of the University of California.
4169689Skan * All rights reserved.
5169689Skan *
6169689Skan * This code is derived from software contributed to Berkeley by
7169689Skan * William Jolitz.
8169689Skan *
9169689Skan * Redistribution and use in source and binary forms, with or without
10169689Skan * modification, are permitted provided that the following conditions
11169689Skan * are met:
12169689Skan * 1. Redistributions of source code must retain the above copyright
13169689Skan *    notice, this list of conditions and the following disclaimer.
14169689Skan * 2. Redistributions in binary form must reproduce the above copyright
15169689Skan *    notice, this list of conditions and the following disclaimer in the
16169689Skan *    documentation and/or other materials provided with the distribution.
17169689Skan * 3. All advertising materials mentioning features or use of this software
18169689Skan *    must display the following acknowledgement:
19169689Skan *	This product includes software developed by the University of
20169689Skan *	California, Berkeley and its contributors.
21169689Skan * 4. Neither the name of the University nor the names of its contributors
22169689Skan *    may be used to endorse or promote products derived from this software
23169689Skan *    without specific prior written permission.
24169689Skan *
25169689Skan * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26169689Skan * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27169689Skan * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28169689Skan * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29169689Skan * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30169689Skan * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31169689Skan * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32169689Skan * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33169689Skan * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34169689Skan * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35169689Skan * SUCH DAMAGE.
36169689Skan *
37169689Skan *	from: @(#)segments.h	7.1 (Berkeley) 5/9/91
38169689Skan *	$Id$
39169689Skan */
40169689Skan
41169689Skan/*
42169689Skan * 386 Segmentation Data Structures and definitions
43169689Skan *	William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
44169689Skan */
45169689Skan
46169689Skan/*
47169689Skan * Selectors
48169689Skan */
49169689Skan
50169689Skan#define	ISPL(s)	((s)&3)		/* what is the priority level of a selector */
51169689Skan#define	SEL_KPL	0		/* kernel priority level */
52169689Skan#define	SEL_UPL	3		/* user priority level */
53169689Skan#define	ISLDT(s)	((s)&SEL_LDT)	/* is it local or global */
54169689Skan#define	SEL_LDT	4		/* local descriptor table */
55169689Skan#define	IDXSEL(s)	(((s)>>3) & 0x1fff)		/* index of selector */
56169689Skan#define	LSEL(s,r)	(((s)<<3) | SEL_LDT | r)	/* a local selector */
57169689Skan#define	GSEL(s,r)	(((s)<<3) | r)			/* a global selector */
58169689Skan
59169689Skan/*
60169689Skan * Memory and System segment descriptors
61169689Skan */
62169689Skanstruct	segment_descriptor	{
63169689Skan	unsigned sd_lolimit:16 ;	/* segment extent (lsb) */
64169689Skan	unsigned sd_lobase:24 ;		/* segment base address (lsb) */
65169689Skan	unsigned sd_type:5 ;		/* segment type */
66169689Skan	unsigned sd_dpl:2 ;		/* segment descriptor priority level */
67169689Skan	unsigned sd_p:1 ;		/* segment descriptor present */
68169689Skan	unsigned sd_hilimit:4 ;		/* segment extent (msb) */
69169689Skan	unsigned sd_xx:2 ;		/* unused */
70169689Skan	unsigned sd_def32:1 ;		/* default 32 vs 16 bit size */
71169689Skan	unsigned sd_gran:1 ;		/* limit granularity (byte/page units)*/
72169689Skan	unsigned sd_hibase:8 ;		/* segment base address  (msb) */
73169689Skan} ;
74169689Skan
75169689Skan/*
76169689Skan * Gate descriptors (e.g. indirect descriptors)
77169689Skan */
78169689Skanstruct	gate_descriptor	{
79169689Skan	unsigned gd_looffset:16 ;	/* gate offset (lsb) */
80169689Skan	unsigned gd_selector:16 ;	/* gate segment selector */
81169689Skan	unsigned gd_stkcpy:5 ;		/* number of stack wds to cpy */
82169689Skan	unsigned gd_xx:3 ;		/* unused */
83169689Skan	unsigned gd_type:5 ;		/* segment type */
84169689Skan	unsigned gd_dpl:2 ;		/* segment descriptor priority level */
85169689Skan	unsigned gd_p:1 ;		/* segment descriptor present */
86169689Skan	unsigned gd_hioffset:16 ;	/* gate offset (msb) */
87169689Skan} ;
88169689Skan
89169689Skan/*
90169689Skan * Generic descriptor
91169689Skan */
92169689Skanunion	descriptor	{
93169689Skan	struct	segment_descriptor sd;
94169689Skan	struct	gate_descriptor gd;
95169689Skan};
96169689Skan
97169689Skan	/* system segments and gate types */
98169689Skan#define	SDT_SYSNULL	 0	/* system null */
99169689Skan#define	SDT_SYS286TSS	 1	/* system 286 TSS available */
100169689Skan#define	SDT_SYSLDT	 2	/* system local descriptor table */
101169689Skan#define	SDT_SYS286BSY	 3	/* system 286 TSS busy */
102169689Skan#define	SDT_SYS286CGT	 4	/* system 286 call gate */
103169689Skan#define	SDT_SYSTASKGT	 5	/* system task gate */
104169689Skan#define	SDT_SYS286IGT	 6	/* system 286 interrupt gate */
105169689Skan#define	SDT_SYS286TGT	 7	/* system 286 trap gate */
106169689Skan#define	SDT_SYSNULL2	 8	/* system null again */
107169689Skan#define	SDT_SYS386TSS	 9	/* system 386 TSS available */
108169689Skan#define	SDT_SYSNULL3	10	/* system null again */
109169689Skan#define	SDT_SYS386BSY	11	/* system 386 TSS busy */
110169689Skan#define	SDT_SYS386CGT	12	/* system 386 call gate */
111169689Skan#define	SDT_SYSNULL4	13	/* system null again */
112169689Skan#define	SDT_SYS386IGT	14	/* system 386 interrupt gate */
113169689Skan#define	SDT_SYS386TGT	15	/* system 386 trap gate */
114169689Skan
115169689Skan	/* memory segment types */
116169689Skan#define	SDT_MEMRO	16	/* memory read only */
117169689Skan#define	SDT_MEMROA	17	/* memory read only accessed */
118169689Skan#define	SDT_MEMRW	18	/* memory read write */
119169689Skan#define	SDT_MEMRWA	19	/* memory read write accessed */
120169689Skan#define	SDT_MEMROD	20	/* memory read only expand dwn limit */
121169689Skan#define	SDT_MEMRODA	21	/* memory read only expand dwn limit accessed */
122169689Skan#define	SDT_MEMRWD	22	/* memory read write expand dwn limit */
123169689Skan#define	SDT_MEMRWDA	23	/* memory read write expand dwn limit acessed */
124169689Skan#define	SDT_MEME	24	/* memory execute only */
125169689Skan#define	SDT_MEMEA	25	/* memory execute only accessed */
126169689Skan#define	SDT_MEMER	26	/* memory execute read */
127169689Skan#define	SDT_MEMERA	27	/* memory execute read accessed */
128169689Skan#define	SDT_MEMEC	28	/* memory execute only conforming */
129169689Skan#define	SDT_MEMEAC	29	/* memory execute only accessed conforming */
130169689Skan#define	SDT_MEMERC	30	/* memory execute read conforming */
131169689Skan#define	SDT_MEMERAC	31	/* memory execute read accessed conforming */
132169689Skan
133169689Skan/* is memory segment descriptor pointer ? */
134169689Skan#define ISMEMSDP(s)	((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC)
135169689Skan
136169689Skan/* is 286 gate descriptor pointer ? */
137169689Skan#define IS286GDP(s)	(((s->d_type) >= SDT_SYS286CGT \
138169689Skan				 && (s->d_type) < SDT_SYS286TGT))
139169689Skan
140169689Skan/* is 386 gate descriptor pointer ? */
141169689Skan#define IS386GDP(s)	(((s->d_type) >= SDT_SYS386CGT \
142169689Skan				&& (s->d_type) < SDT_SYS386TGT))
143169689Skan
144169689Skan/* is gate descriptor pointer ? */
145169689Skan#define ISGDP(s)	(IS286GDP(s) || IS386GDP(s))
146169689Skan
147169689Skan/* is segment descriptor pointer ? */
148169689Skan#define ISSDP(s)	(ISMEMSDP(s) || !ISGDP(s))
149169689Skan
150169689Skan/* is system segment descriptor pointer ? */
151169689Skan#define ISSYSSDP(s)	(!ISMEMSDP(s) && !ISGDP(s))
152169689Skan
153169689Skan/*
154169689Skan * Software definitions are in this convenient format,
155169689Skan * which are translated into inconvenient segment descriptors
156169689Skan * when needed to be used by the 386 hardware
157169689Skan */
158169689Skan
159169689Skanstruct	soft_segment_descriptor	{
160169689Skan	unsigned ssd_base ;		/* segment base address  */
161169689Skan	unsigned ssd_limit ;		/* segment extent */
162169689Skan	unsigned ssd_type:5 ;		/* segment type */
163169689Skan	unsigned ssd_dpl:2 ;		/* segment descriptor priority level */
164169689Skan	unsigned ssd_p:1 ;		/* segment descriptor present */
165169689Skan	unsigned ssd_xx:4 ;		/* unused */
166169689Skan	unsigned ssd_xx1:2 ;		/* unused */
167169689Skan	unsigned ssd_def32:1 ;		/* default 32 vs 16 bit size */
168169689Skan	unsigned ssd_gran:1 ;		/* limit granularity (byte/page units)*/
169169689Skan};
170169689Skan
171169689Skanextern ssdtosd() ;	/* to decode a ssd */
172169689Skanextern sdtossd() ;	/* to encode a sd */
173169689Skan
174169689Skan/*
175169689Skan * region descriptors, used to load gdt/idt tables before segments yet exist.
176169689Skan */
177169689Skanstruct region_descriptor {
178169689Skan	unsigned rd_limit:16;		/* segment extent */
179169689Skan	unsigned rd_base:32;		/* base address  */
180169689Skan};
181169689Skan
182169689Skan/*
183169689Skan * Segment Protection Exception code bits
184169689Skan */
185169689Skan
186169689Skan#define	SEGEX_EXT	0x01	/* recursive or externally induced */
187169689Skan#define	SEGEX_IDT	0x02	/* interrupt descriptor table */
188169689Skan#define	SEGEX_TI	0x04	/* local descriptor table */
189169689Skan				/* other bits are affected descriptor index */
190169689Skan#define SEGEX_IDX(s)	((s)>>3)&0x1fff)
191169689Skan
192169689Skan/*
193169689Skan * Size of IDT table
194169689Skan */
195169689Skan
196169689Skan#define	NIDT	256
197169689Skan#define	NRSVIDT	32		/* reserved entries for cpu exceptions */
198169689Skan