1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1990 William F. Jolitz
5 * Copyright (c) 1990 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * William Jolitz.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 *	from: @(#)segments.h	7.1 (Berkeley) 5/9/91
36 * $FreeBSD$
37 */
38
39#ifndef _MACHINE_SEGMENTS_H_
40#define	_MACHINE_SEGMENTS_H_
41
42/*
43 * 386 Segmentation Data Structures and definitions
44 *	William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
45 */
46
47#include <x86/segments.h>
48
49/*
50 * Software definitions are in this convenient format,
51 * which are translated into inconvenient segment descriptors
52 * when needed to be used by the 386 hardware
53 */
54
55struct	soft_segment_descriptor	{
56	unsigned ssd_base ;		/* segment base address  */
57	unsigned ssd_limit ;		/* segment extent */
58	unsigned ssd_type:5 ;		/* segment type */
59	unsigned ssd_dpl:2 ;		/* segment descriptor priority level */
60	unsigned ssd_p:1 ;		/* segment descriptor present */
61	unsigned ssd_xx:4 ;		/* unused */
62	unsigned ssd_xx1:2 ;		/* unused */
63	unsigned ssd_def32:1 ;		/* default 32 vs 16 bit size */
64	unsigned ssd_gran:1 ;		/* limit granularity (byte/page units)*/
65};
66
67/*
68 * region descriptors, used to load gdt/idt tables before segments yet exist.
69 */
70struct region_descriptor {
71	unsigned rd_limit:16;		/* segment extent */
72	unsigned rd_base:32 __packed;	/* base address  */
73};
74
75/*
76 * Segment Protection Exception code bits
77 */
78
79#define	SEGEX_EXT	0x01	/* recursive or externally induced */
80#define	SEGEX_IDT	0x02	/* interrupt descriptor table */
81#define	SEGEX_TI	0x04	/* local descriptor table */
82				/* other bits are affected descriptor index */
83#define SEGEX_IDX(s)	(((s)>>3)&0x1fff)
84
85#ifdef _KERNEL
86extern int	_default_ldt;
87extern union descriptor *gdt;
88extern union descriptor *ldt;
89extern struct soft_segment_descriptor gdt_segs[];
90extern struct gate_descriptor *idt;
91
92void	lgdt(struct region_descriptor *rdp);
93void	sdtossd(struct segment_descriptor *sdp,
94	    struct soft_segment_descriptor *ssdp);
95void	ssdtosd(struct soft_segment_descriptor *ssdp,
96	    struct segment_descriptor *sdp);
97#endif /* _KERNEL */
98
99#endif /* !_MACHINE_SEGMENTS_H_ */
100