1 /* $NetBSD: segments.h,v 1.10 1995/03/28 18:17:18 jtc Exp $ */ 2 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. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)segments.h 7.1 (Berkeley) 5/9/91 40 */ 41 42 /* 43 * 386 Segmentation Data Structures and definitions 44 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 45 */ 46 47 #ifndef _I386_SEGMENTS_H_ 48 #define _I386_SEGMENTS_H_ 49 50 #if __GNUC__ >= 2 51 #pragma pack(1) 52 #endif 53 54 /* 55 * Selectors 56 */ 57 58 #define ISPL(s) ((s)&3) /* what is the priority level of a selector */ 59 #define SEL_KPL 0 /* kernel priority level */ 60 #define SEL_UPL 3 /* user priority level */ 61 #define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */ 62 #define SEL_LDT 4 /* local descriptor table */ 63 #define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */ 64 #define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */ 65 #define GSEL(s,r) (((s)<<3) | r) /* a global selector */ 66 67 /* 68 * Memory and System segment descriptors 69 */ 70 struct segment_descriptor { 71 unsigned sd_lolimit:16; /* segment extent (lsb) */ 72 unsigned sd_lobase:24; /* segment base address (lsb) */ 73 unsigned sd_type:5; /* segment type */ 74 unsigned sd_dpl:2; /* segment descriptor priority level */ 75 unsigned sd_p:1; /* segment descriptor present */ 76 unsigned sd_hilimit:4; /* segment extent (msb) */ 77 unsigned sd_xx:2; /* unused */ 78 unsigned sd_def32:1; /* default 32 vs 16 bit size */ 79 unsigned sd_gran:1; /* limit granularity (byte/page) */ 80 unsigned sd_hibase:8; /* segment base address (msb) */ 81 }; 82 83 /* 84 * Gate descriptors (e.g. indirect descriptors) 85 */ 86 struct gate_descriptor { 87 unsigned gd_looffset:16; /* gate offset (lsb) */ 88 unsigned gd_selector:16; /* gate segment selector */ 89 unsigned gd_stkcpy:5; /* number of stack wds to cpy */ 90 unsigned gd_xx:3; /* unused */ 91 unsigned gd_type:5; /* segment type */ 92 unsigned gd_dpl:2; /* segment descriptor priority level */ 93 unsigned gd_p:1; /* segment descriptor present */ 94 unsigned gd_hioffset:16; /* gate offset (msb) */ 95 }; 96 97 /* 98 * Generic descriptor 99 */ 100 union descriptor { 101 struct segment_descriptor sd; 102 struct gate_descriptor gd; 103 }; 104 105 /* system segments and gate types */ 106 #define SDT_SYSNULL 0 /* system null */ 107 #define SDT_SYS286TSS 1 /* system 286 TSS available */ 108 #define SDT_SYSLDT 2 /* system local descriptor table */ 109 #define SDT_SYS286BSY 3 /* system 286 TSS busy */ 110 #define SDT_SYS286CGT 4 /* system 286 call gate */ 111 #define SDT_SYSTASKGT 5 /* system task gate */ 112 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 113 #define SDT_SYS286TGT 7 /* system 286 trap gate */ 114 #define SDT_SYSNULL2 8 /* system null again */ 115 #define SDT_SYS386TSS 9 /* system 386 TSS available */ 116 #define SDT_SYSNULL3 10 /* system null again */ 117 #define SDT_SYS386BSY 11 /* system 386 TSS busy */ 118 #define SDT_SYS386CGT 12 /* system 386 call gate */ 119 #define SDT_SYSNULL4 13 /* system null again */ 120 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 121 #define SDT_SYS386TGT 15 /* system 386 trap gate */ 122 123 /* memory segment types */ 124 #define SDT_MEMRO 16 /* memory read only */ 125 #define SDT_MEMROA 17 /* memory read only accessed */ 126 #define SDT_MEMRW 18 /* memory read write */ 127 #define SDT_MEMRWA 19 /* memory read write accessed */ 128 #define SDT_MEMROD 20 /* memory read only expand dwn limit */ 129 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 130 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 131 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 132 #define SDT_MEME 24 /* memory execute only */ 133 #define SDT_MEMEA 25 /* memory execute only accessed */ 134 #define SDT_MEMER 26 /* memory execute read */ 135 #define SDT_MEMERA 27 /* memory execute read accessed */ 136 #define SDT_MEMEC 28 /* memory execute only conforming */ 137 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 138 #define SDT_MEMERC 30 /* memory execute read conforming */ 139 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 140 141 /* is memory segment descriptor pointer ? */ 142 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC) 143 144 /* is 286 gate descriptor pointer ? */ 145 #define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \ 146 && (s->d_type) < SDT_SYS286TGT)) 147 148 /* is 386 gate descriptor pointer ? */ 149 #define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \ 150 && (s->d_type) < SDT_SYS386TGT)) 151 152 /* is gate descriptor pointer ? */ 153 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 154 155 /* is segment descriptor pointer ? */ 156 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 157 158 /* is system segment descriptor pointer ? */ 159 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 160 161 /* 162 * Software definitions are in this convenient format, 163 * which are translated into inconvenient segment descriptors 164 * when needed to be used by the 386 hardware 165 */ 166 struct soft_segment_descriptor { 167 unsigned ssd_base; /* segment base address */ 168 unsigned ssd_limit; /* segment extent */ 169 unsigned ssd_type:5; /* segment type */ 170 unsigned ssd_dpl:2; /* segment descriptor priority level */ 171 unsigned ssd_p:1; /* segment descriptor present */ 172 unsigned ssd_xx:4; /* unused */ 173 unsigned ssd_xx1:2; /* unused */ 174 unsigned ssd_def32:1; /* default 32 vs 16 bit size */ 175 unsigned ssd_gran:1; /* limit granularity (byte/page units)*/ 176 }; 177 178 /* 179 * region descriptors, used to load gdt/idt tables before segments yet exist. 180 */ 181 struct region_descriptor { 182 unsigned rd_limit:16; /* segment extent */ 183 unsigned rd_base:32; /* base address */ 184 }; 185 186 /* 187 * Segment Protection Exception code bits 188 */ 189 #define SEGEX_EXT 0x01 /* recursive or externally induced */ 190 #define SEGEX_IDT 0x02 /* interrupt descriptor table */ 191 #define SEGEX_TI 0x04 /* local descriptor table */ 192 /* other bits are affected descriptor index */ 193 #define SEGEX_IDX(s) ((s)>>3)&0x1fff) 194 195 /* 196 * Entries in the Interrupt Descriptor Table (IDT) 197 */ 198 #define NIDT 256 199 #define NRSVIDT 32 /* reserved entries for cpu exceptions */ 200 201 /* 202 * Entries in the Global Descriptor Table (GDT) 203 */ 204 #define GNULL_SEL 0 /* Null Descriptor */ 205 #define GCODE_SEL 1 /* Kernel Code Descriptor */ 206 #define GDATA_SEL 2 /* Kernel Data Descriptor */ 207 #define GLDT_SEL 3 /* LDT - eventually one per process */ 208 #define GTGATE_SEL 4 /* Process task switch gate */ 209 #define GPANIC_SEL 5 /* Task state to consider panic from */ 210 #define GPROC0_SEL 6 /* Task state process slot zero and up */ 211 #define GUSERLDT_SEL 7 /* User LDT */ 212 #define NGDT GUSERLDT_SEL+1 213 214 /* 215 * Entries in the Local Descriptor Table (LDT) 216 */ 217 #define LSYS5CALLS_SEL 0 /* forced by intel BCS */ 218 #define LSYS5SIGR_SEL 1 219 #define L43BSDCALLS_SEL 2 /* notyet */ 220 #define LUCODE_SEL 3 221 #define LUDATA_SEL 4 222 #if 0 223 /* XXX seperate stack, es,fs,gs sels ? */ 224 #define LPOSIXCALLS_SEL 5 /* notyet */ 225 #endif 226 #define NLDT LUDATA_SEL+1 227 228 #ifdef _KERNEL 229 extern int currentldt; 230 extern union descriptor gdt[NGDT]; 231 extern union descriptor ldt[NLDT]; 232 extern struct soft_segment_descriptor gdt_segs[]; 233 void ssdtosd __P((struct soft_segment_descriptor *, struct segment_descriptor *)); 234 void sdtossd __P((struct segment_descriptor *, struct soft_segment_descriptor *)); 235 #endif 236 237 #if __GNUC__ >= 2 238 #pragma pack(4) 239 #endif 240 241 #endif /* _I386_SEGMENTS_H_ */ 242