2 * Copyright (c) 1989, 1990 William F. Jolitz
3 * Copyright (c) 1990 The Regents of the University of California.
6 * This code is derived from software contributed to Berkeley by
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10 * modification, are permitted provided that the following conditions
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19 * This product includes software developed by the University of
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25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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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 $
39 * $DragonFly: src/sys/i386/include/Attic/segments.h,v 1.11 2006/05/20 02:42:06 dillon Exp $
42 #ifndef _MACHINE_SEGMENTS_H_
43 #define _MACHINE_SEGMENTS_H_
46 * 386 Segmentation Data Structures and definitions
47 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
54 #define SEL_RPL_MASK 0x0003
56 #define ISPL(s) ((s)&3) /* what is the priority level of a selector */
57 #define SEL_KPL 0 /* kernel priority level */
58 #define SEL_UPL 3 /* user priority level */
59 #define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */
60 #define SEL_LDT 4 /* local descriptor table */
61 #define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */
62 #define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */
63 #define GSEL(s,r) (((s)<<3) | r) /* a global selector */
68 * Memory and System segment descriptors
70 struct segment_descriptor {
71 unsigned sd_lolimit:16 ; /* segment extent (lsb) */
72 unsigned sd_lobase:24 __attribute__ ((packed));
73 /* segment base address (lsb) */
74 unsigned sd_type:5 ; /* segment type */
75 unsigned sd_dpl:2 ; /* segment descriptor priority level */
76 unsigned sd_p:1 ; /* segment descriptor present */
77 unsigned sd_hilimit:4 ; /* segment extent (msb) */
78 unsigned sd_xx:2 ; /* unused */
79 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */
80 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/
81 unsigned sd_hibase:8 ; /* segment base address (msb) */
85 * Gate descriptors (e.g. indirect descriptors)
87 struct gate_descriptor {
88 unsigned gd_looffset:16 ; /* gate offset (lsb) */
89 unsigned gd_selector:16 ; /* gate segment selector */
90 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */
91 unsigned gd_xx:3 ; /* unused */
92 unsigned gd_type:5 ; /* segment type */
93 unsigned gd_dpl:2 ; /* segment descriptor priority level */
94 unsigned gd_p:1 ; /* segment descriptor present */
95 unsigned gd_hioffset:16 ; /* gate offset (msb) */
102 struct segment_descriptor sd;
103 struct gate_descriptor gd;
108 /* system segments and gate types */
109 #define SDT_SYSNULL 0 /* system null */
110 #define SDT_SYS286TSS 1 /* system 286 TSS available */
111 #define SDT_SYSLDT 2 /* system local descriptor table */
112 #define SDT_SYS286BSY 3 /* system 286 TSS busy */
113 #define SDT_SYS286CGT 4 /* system 286 call gate */
114 #define SDT_SYSTASKGT 5 /* system task gate */
115 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
116 #define SDT_SYS286TGT 7 /* system 286 trap gate */
117 #define SDT_SYSNULL2 8 /* system null again */
118 #define SDT_SYS386TSS 9 /* system 386 TSS available */
119 #define SDT_SYSNULL3 10 /* system null again */
120 #define SDT_SYS386BSY 11 /* system 386 TSS busy */
121 #define SDT_SYS386CGT 12 /* system 386 call gate */
122 #define SDT_SYSNULL4 13 /* system null again */
123 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
124 #define SDT_SYS386TGT 15 /* system 386 trap gate */
126 /* memory segment types */
127 #define SDT_MEMRO 16 /* memory read only */
128 #define SDT_MEMROA 17 /* memory read only accessed */
129 #define SDT_MEMRW 18 /* memory read write */
130 #define SDT_MEMRWA 19 /* memory read write accessed */
131 #define SDT_MEMROD 20 /* memory read only expand dwn limit */
132 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
133 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
134 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
135 #define SDT_MEME 24 /* memory execute only */
136 #define SDT_MEMEA 25 /* memory execute only accessed */
137 #define SDT_MEMER 26 /* memory execute read */
138 #define SDT_MEMERA 27 /* memory execute read accessed */
139 #define SDT_MEMEC 28 /* memory execute only conforming */
140 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
141 #define SDT_MEMERC 30 /* memory execute read conforming */
142 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
146 /* is memory segment descriptor pointer ? */
147 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC)
149 /* is 286 gate descriptor pointer ? */
150 #define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \
151 && (s->d_type) < SDT_SYS286TGT))
153 /* is 386 gate descriptor pointer ? */
154 #define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \
155 && (s->d_type) < SDT_SYS386TGT))
157 /* is gate descriptor pointer ? */
158 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
160 /* is segment descriptor pointer ? */
161 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
163 /* is system segment descriptor pointer ? */
164 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
167 * Software definitions are in this convenient format,
168 * which are translated into inconvenient segment descriptors
169 * when needed to be used by the 386 hardware
172 struct soft_segment_descriptor {
173 unsigned ssd_base ; /* segment base address */
174 unsigned ssd_limit ; /* segment extent */
175 unsigned ssd_type:5 ; /* segment type */
176 unsigned ssd_dpl:2 ; /* segment descriptor priority level */
177 unsigned ssd_p:1 ; /* segment descriptor present */
178 unsigned ssd_xx:4 ; /* unused */
179 unsigned ssd_xx1:2 ; /* unused */
180 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */
181 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/
185 * region descriptors, used to load gdt/idt tables before segments yet exist.
187 struct region_descriptor {
188 unsigned rd_limit:16; /* segment extent */
189 unsigned rd_base:32 __attribute__ ((packed)); /* base address */
195 * Segment Protection Exception code bits
198 #define SEGEX_EXT 0x01 /* recursive or externally induced */
199 #define SEGEX_IDT 0x02 /* interrupt descriptor table */
200 #define SEGEX_TI 0x04 /* local descriptor table */
201 /* other bits are affected descriptor index */
202 #define SEGEX_IDX(s) ((s)>>3)&0x1fff)
205 * Size of IDT table. Theoretically we only need to cover past 0x81
206 * (NIDT=130) if not running APIC_IO or SMP, but at this point we might
207 * as well just use all of them.
209 #define NIDT 256 /* we use them all */
212 * Entries in the Global Descriptor Table (GDT)
214 #define GNULL_SEL 0 /* Null Descriptor */
215 #define GCODE_SEL 1 /* Kernel Code Descriptor */
216 #define GDATA_SEL 2 /* Kernel Data Descriptor */
217 #define GPRIV_SEL 3 /* SMP Per-Processor Private Data */
218 #define GPROC0_SEL 4 /* Task state process slot zero and up */
219 #define GLDT_SEL 5 /* LDT - eventually one per process */
220 #define GUSERLDT_SEL 6 /* User LDT */
221 #define GTGATE_SEL 7 /* Process task switch gate */
222 #define GBIOSLOWMEM_SEL 8 /* BIOS low memory access (must be entry 8) */
223 #define GPANIC_SEL 9 /* Task state to consider panic from */
224 #define GBIOSCODE32_SEL 10 /* BIOS interface (32bit Code) */
225 #define GBIOSCODE16_SEL 11 /* BIOS interface (16bit Code) */
226 #define GBIOSDATA_SEL 12 /* BIOS interface (Data) */
227 #define GBIOSUTIL_SEL 13 /* BIOS interface (Utility) */
228 #define GBIOSARGS_SEL 14 /* BIOS interface (Arguments) */
229 #define GTLS_START 15 /* Thread TLS Descriptor */
230 #define GTLS_END 17 /* Thread TLS Descriptor */
232 #define NGTLS (GTLS_END - GTLS_START + 1)
234 #define NGDT 21 /* some of 11-17 are reserved for debugger */
240 * Entries in the Local Descriptor Table (LDT)
242 #define LSYS5CALLS_SEL 0 /* forced by intel BCS */
243 #define LSYS5SIGR_SEL 1
244 #define L43BSDCALLS_SEL 2 /* notyet */
246 #define LSOL26CALLS_SEL 4 /* Solaris >= 2.6 system call gate */
248 /* separate stack, es,fs,gs sels ? */
249 /* #define LPOSIXCALLS_SEL 5*/ /* notyet */
250 #define LBSDICALLS_SEL 16 /* BSDI system call gate */
251 #define NLDT (LBSDICALLS_SEL + 1)
253 #if defined(_KERNEL) && !defined(LOCORE)
255 #ifndef _SYS_TYPES_H_
256 #include <sys/types.h>
259 extern int _default_ldt;
260 extern union descriptor gdt[];
261 extern struct soft_segment_descriptor gdt_segs[];
262 extern struct gate_descriptor *idt;
263 extern union descriptor ldt[NLDT];
265 void lgdt (struct region_descriptor *rdp);
266 void lidt (struct region_descriptor *rdp);
267 void lldt (u_short sel);
268 void sdtossd (struct segment_descriptor *sdp,
269 struct soft_segment_descriptor *ssdp);
270 void ssdtosd (struct soft_segment_descriptor *ssdp,
271 struct segment_descriptor *sdp);
274 #endif /* !_MACHINE_SEGMENTS_H_ */