what the heck one last one before i go take a nap...
[dragonfly.git] / sys / cpu / i386 / include / segments.h
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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: src/sys/i386/include/segments.h,v 1.24 1999/12/29 04:33:07 peter Exp $
3ae0cd58 39 * $DragonFly: src/sys/cpu/i386/include/segments.h,v 1.6 2003/08/26 21:42:18 rob Exp $
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40 */
41
42#ifndef _MACHINE_SEGMENTS_H_
43#define _MACHINE_SEGMENTS_H_
44
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45/*
46 * 386 Segmentation Data Structures and definitions
47 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
48 */
49
50/*
51 * Selectors
52 */
53
54#define ISPL(s) ((s)&3) /* what is the priority level of a selector */
55#define SEL_KPL 0 /* kernel priority level */
56#define SEL_UPL 3 /* user priority level */
57#define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */
58#define SEL_LDT 4 /* local descriptor table */
59#define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */
60#define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */
61#define GSEL(s,r) (((s)<<3) | r) /* a global selector */
62
63/*
64 * Memory and System segment descriptors
65 */
66struct segment_descriptor {
67 unsigned sd_lolimit:16 ; /* segment extent (lsb) */
68 unsigned sd_lobase:24 __attribute__ ((packed));
69 /* segment base address (lsb) */
70 unsigned sd_type:5 ; /* segment type */
71 unsigned sd_dpl:2 ; /* segment descriptor priority level */
72 unsigned sd_p:1 ; /* segment descriptor present */
73 unsigned sd_hilimit:4 ; /* segment extent (msb) */
74 unsigned sd_xx:2 ; /* unused */
75 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */
76 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/
77 unsigned sd_hibase:8 ; /* segment base address (msb) */
78} ;
79
80/*
81 * Gate descriptors (e.g. indirect descriptors)
82 */
83struct gate_descriptor {
84 unsigned gd_looffset:16 ; /* gate offset (lsb) */
85 unsigned gd_selector:16 ; /* gate segment selector */
86 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */
87 unsigned gd_xx:3 ; /* unused */
88 unsigned gd_type:5 ; /* segment type */
89 unsigned gd_dpl:2 ; /* segment descriptor priority level */
90 unsigned gd_p:1 ; /* segment descriptor present */
91 unsigned gd_hioffset:16 ; /* gate offset (msb) */
92} ;
93
94/*
95 * Generic descriptor
96 */
97union descriptor {
98 struct segment_descriptor sd;
99 struct gate_descriptor gd;
100};
101
102 /* system segments and gate types */
103#define SDT_SYSNULL 0 /* system null */
104#define SDT_SYS286TSS 1 /* system 286 TSS available */
105#define SDT_SYSLDT 2 /* system local descriptor table */
106#define SDT_SYS286BSY 3 /* system 286 TSS busy */
107#define SDT_SYS286CGT 4 /* system 286 call gate */
108#define SDT_SYSTASKGT 5 /* system task gate */
109#define SDT_SYS286IGT 6 /* system 286 interrupt gate */
110#define SDT_SYS286TGT 7 /* system 286 trap gate */
111#define SDT_SYSNULL2 8 /* system null again */
112#define SDT_SYS386TSS 9 /* system 386 TSS available */
113#define SDT_SYSNULL3 10 /* system null again */
114#define SDT_SYS386BSY 11 /* system 386 TSS busy */
115#define SDT_SYS386CGT 12 /* system 386 call gate */
116#define SDT_SYSNULL4 13 /* system null again */
117#define SDT_SYS386IGT 14 /* system 386 interrupt gate */
118#define SDT_SYS386TGT 15 /* system 386 trap gate */
119
120 /* memory segment types */
121#define SDT_MEMRO 16 /* memory read only */
122#define SDT_MEMROA 17 /* memory read only accessed */
123#define SDT_MEMRW 18 /* memory read write */
124#define SDT_MEMRWA 19 /* memory read write accessed */
125#define SDT_MEMROD 20 /* memory read only expand dwn limit */
126#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
127#define SDT_MEMRWD 22 /* memory read write expand dwn limit */
128#define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
129#define SDT_MEME 24 /* memory execute only */
130#define SDT_MEMEA 25 /* memory execute only accessed */
131#define SDT_MEMER 26 /* memory execute read */
132#define SDT_MEMERA 27 /* memory execute read accessed */
133#define SDT_MEMEC 28 /* memory execute only conforming */
134#define SDT_MEMEAC 29 /* memory execute only accessed conforming */
135#define SDT_MEMERC 30 /* memory execute read conforming */
136#define SDT_MEMERAC 31 /* memory execute read accessed conforming */
137
138/* is memory segment descriptor pointer ? */
139#define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC)
140
141/* is 286 gate descriptor pointer ? */
142#define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \
143 && (s->d_type) < SDT_SYS286TGT))
144
145/* is 386 gate descriptor pointer ? */
146#define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \
147 && (s->d_type) < SDT_SYS386TGT))
148
149/* is gate descriptor pointer ? */
150#define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
151
152/* is segment descriptor pointer ? */
153#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
154
155/* is system segment descriptor pointer ? */
156#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
157
158/*
159 * Software definitions are in this convenient format,
160 * which are translated into inconvenient segment descriptors
161 * when needed to be used by the 386 hardware
162 */
163
164struct soft_segment_descriptor {
165 unsigned ssd_base ; /* segment base address */
166 unsigned ssd_limit ; /* segment extent */
167 unsigned ssd_type:5 ; /* segment type */
168 unsigned ssd_dpl:2 ; /* segment descriptor priority level */
169 unsigned ssd_p:1 ; /* segment descriptor present */
170 unsigned ssd_xx:4 ; /* unused */
171 unsigned ssd_xx1:2 ; /* unused */
172 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */
173 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/
174};
175
176/*
177 * region descriptors, used to load gdt/idt tables before segments yet exist.
178 */
179struct region_descriptor {
180 unsigned rd_limit:16; /* segment extent */
181 unsigned rd_base:32 __attribute__ ((packed)); /* base address */
182};
183
184/*
185 * Segment Protection Exception code bits
186 */
187
188#define SEGEX_EXT 0x01 /* recursive or externally induced */
189#define SEGEX_IDT 0x02 /* interrupt descriptor table */
190#define SEGEX_TI 0x04 /* local descriptor table */
191 /* other bits are affected descriptor index */
192#define SEGEX_IDX(s) ((s)>>3)&0x1fff)
193
194/*
195 * Size of IDT table
196 */
197
198#if defined(SMP) || defined(APIC_IO)
199#define NIDT 256 /* we use them all */
200#else
a64ba182 201#define NIDT 130 /* 32 reserved, 16 h/w, 0 s/w, 0x80, 0x81 */
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202#endif /* SMP || APIC_IO */
203#define NRSVIDT 32 /* reserved entries for cpu exceptions */
204
205/*
206 * Entries in the Global Descriptor Table (GDT)
207 */
208#define GNULL_SEL 0 /* Null Descriptor */
209#define GCODE_SEL 1 /* Kernel Code Descriptor */
210#define GDATA_SEL 2 /* Kernel Data Descriptor */
211#define GPRIV_SEL 3 /* SMP Per-Processor Private Data */
212#define GPROC0_SEL 4 /* Task state process slot zero and up */
213#define GLDT_SEL 5 /* LDT - eventually one per process */
214#define GUSERLDT_SEL 6 /* User LDT */
215#define GTGATE_SEL 7 /* Process task switch gate */
216#define GBIOSLOWMEM_SEL 8 /* BIOS low memory access (must be entry 8) */
217#define GPANIC_SEL 9 /* Task state to consider panic from */
218#define GBIOSCODE32_SEL 10 /* BIOS interface (32bit Code) */
219#define GBIOSCODE16_SEL 11 /* BIOS interface (16bit Code) */
220#define GBIOSDATA_SEL 12 /* BIOS interface (Data) */
221#define GBIOSUTIL_SEL 13 /* BIOS interface (Utility) */
222#define GBIOSARGS_SEL 14 /* BIOS interface (Arguments) */
223
224#ifdef BDE_DEBUGGER
225#define NGDT 18 /* some of 11-17 are reserved for debugger */
226#else
227#define NGDT 15
228#endif
229
230/*
231 * Entries in the Local Descriptor Table (LDT)
232 */
233#define LSYS5CALLS_SEL 0 /* forced by intel BCS */
234#define LSYS5SIGR_SEL 1
235#define L43BSDCALLS_SEL 2 /* notyet */
236#define LUCODE_SEL 3
237#define LSOL26CALLS_SEL 4 /* Solaris >= 2.6 system call gate */
238#define LUDATA_SEL 5
239/* separate stack, es,fs,gs sels ? */
240/* #define LPOSIXCALLS_SEL 5*/ /* notyet */
241#define LBSDICALLS_SEL 16 /* BSDI system call gate */
242#define NLDT (LBSDICALLS_SEL + 1)
243
244#ifdef _KERNEL
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245extern int _default_ldt;
246extern union descriptor gdt[];
247extern struct soft_segment_descriptor gdt_segs[];
248extern struct gate_descriptor *idt;
249extern union descriptor ldt[NLDT];
250
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251void lgdt (struct region_descriptor *rdp);
252void lidt (struct region_descriptor *rdp);
253void lldt (u_short sel);
254void sdtossd (struct segment_descriptor *sdp,
255 struct soft_segment_descriptor *ssdp);
256void ssdtosd (struct soft_segment_descriptor *ssdp,
257 struct segment_descriptor *sdp);
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258#endif /* _KERNEL */
259
260#endif /* !_MACHINE_SEGMENTS_H_ */