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 * $Id: segments.h,v 1.3 1993/11/07 17:43:08 wollman Exp $ 39 */ 40 41 #ifndef _MACHINE_SEGMENTS_H_ 42 #define _MACHINE_SEGMENTS_H_ 1 43 44 /* 45 * 386 Segmentation Data Structures and definitions 46 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 47 */ 48 49 /* 50 * Selectors 51 */ 52 53 #define ISPL(s) ((s)&3) /* what is the priority level of a selector */ 54 #define SEL_KPL 0 /* kernel priority level */ 55 #define SEL_UPL 3 /* user priority level */ 56 #define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */ 57 #define SEL_LDT 4 /* local descriptor table */ 58 #define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */ 59 #define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */ 60 #define GSEL(s,r) (((s)<<3) | r) /* a global selector */ 61 62 /* 63 * Memory and System segment descriptors 64 */ 65 struct segment_descriptor { 66 unsigned sd_lolimit:16 ; /* segment extent (lsb) */ 67 unsigned sd_lobase:24 __attribute__ ((packed)); 68 /* segment base address (lsb) */ 69 unsigned sd_type:5 ; /* segment type */ 70 unsigned sd_dpl:2 ; /* segment descriptor priority level */ 71 unsigned sd_p:1 ; /* segment descriptor present */ 72 unsigned sd_hilimit:4 ; /* segment extent (msb) */ 73 unsigned sd_xx:2 ; /* unused */ 74 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */ 75 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/ 76 unsigned sd_hibase:8 ; /* segment base address (msb) */ 77 } ; 78 79 /* 80 * Gate descriptors (e.g. indirect descriptors) 81 */ 82 struct gate_descriptor { 83 unsigned gd_looffset:16 ; /* gate offset (lsb) */ 84 unsigned gd_selector:16 ; /* gate segment selector */ 85 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */ 86 unsigned gd_xx:3 ; /* unused */ 87 unsigned gd_type:5 ; /* segment type */ 88 unsigned gd_dpl:2 ; /* segment descriptor priority level */ 89 unsigned gd_p:1 ; /* segment descriptor present */ 90 unsigned gd_hioffset:16 ; /* gate offset (msb) */ 91 } ; 92 93 /* 94 * Generic descriptor 95 */ 96 union descriptor { 97 struct segment_descriptor sd; 98 struct gate_descriptor gd; 99 }; 100 101 /* system segments and gate types */ 102 #define SDT_SYSNULL 0 /* system null */ 103 #define SDT_SYS286TSS 1 /* system 286 TSS available */ 104 #define SDT_SYSLDT 2 /* system local descriptor table */ 105 #define SDT_SYS286BSY 3 /* system 286 TSS busy */ 106 #define SDT_SYS286CGT 4 /* system 286 call gate */ 107 #define SDT_SYSTASKGT 5 /* system task gate */ 108 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 109 #define SDT_SYS286TGT 7 /* system 286 trap gate */ 110 #define SDT_SYSNULL2 8 /* system null again */ 111 #define SDT_SYS386TSS 9 /* system 386 TSS available */ 112 #define SDT_SYSNULL3 10 /* system null again */ 113 #define SDT_SYS386BSY 11 /* system 386 TSS busy */ 114 #define SDT_SYS386CGT 12 /* system 386 call gate */ 115 #define SDT_SYSNULL4 13 /* system null again */ 116 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 117 #define SDT_SYS386TGT 15 /* system 386 trap gate */ 118 119 /* memory segment types */ 120 #define SDT_MEMRO 16 /* memory read only */ 121 #define SDT_MEMROA 17 /* memory read only accessed */ 122 #define SDT_MEMRW 18 /* memory read write */ 123 #define SDT_MEMRWA 19 /* memory read write accessed */ 124 #define SDT_MEMROD 20 /* memory read only expand dwn limit */ 125 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 126 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 127 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 128 #define SDT_MEME 24 /* memory execute only */ 129 #define SDT_MEMEA 25 /* memory execute only accessed */ 130 #define SDT_MEMER 26 /* memory execute read */ 131 #define SDT_MEMERA 27 /* memory execute read accessed */ 132 #define SDT_MEMEC 28 /* memory execute only conforming */ 133 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 134 #define SDT_MEMERC 30 /* memory execute read conforming */ 135 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 136 137 /* is memory segment descriptor pointer ? */ 138 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC) 139 140 /* is 286 gate descriptor pointer ? */ 141 #define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \ 142 && (s->d_type) < SDT_SYS286TGT)) 143 144 /* is 386 gate descriptor pointer ? */ 145 #define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \ 146 && (s->d_type) < SDT_SYS386TGT)) 147 148 /* is gate descriptor pointer ? */ 149 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 150 151 /* is segment descriptor pointer ? */ 152 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 153 154 /* is system segment descriptor pointer ? */ 155 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 156 157 /* 158 * Software definitions are in this convenient format, 159 * which are translated into inconvenient segment descriptors 160 * when needed to be used by the 386 hardware 161 */ 162 163 struct soft_segment_descriptor { 164 unsigned ssd_base ; /* segment base address */ 165 unsigned ssd_limit ; /* segment extent */ 166 unsigned ssd_type:5 ; /* segment type */ 167 unsigned ssd_dpl:2 ; /* segment descriptor priority level */ 168 unsigned ssd_p:1 ; /* segment descriptor present */ 169 unsigned ssd_xx:4 ; /* unused */ 170 unsigned ssd_xx1:2 ; /* unused */ 171 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */ 172 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/ 173 }; 174 175 extern ssdtosd() ; /* to decode a ssd */ 176 extern sdtossd() ; /* to encode a sd */ 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 __attribute__ ((packed)); /* base address */ 184 }; 185 186 /* 187 * Segment Protection Exception code bits 188 */ 189 190 #define SEGEX_EXT 0x01 /* recursive or externally induced */ 191 #define SEGEX_IDT 0x02 /* interrupt descriptor table */ 192 #define SEGEX_TI 0x04 /* local descriptor table */ 193 /* other bits are affected descriptor index */ 194 #define SEGEX_IDX(s) ((s)>>3)&0x1fff) 195 196 /* 197 * Size of IDT table 198 */ 199 200 #define NIDT 256 201 #define NRSVIDT 32 /* reserved entries for cpu exceptions */ 202 203 /* 204 * Entries in the Global Descriptor Table (GDT) 205 */ 206 #define GNULL_SEL 0 /* Null Descriptor */ 207 #define GCODE_SEL 1 /* Kernel Code Descriptor */ 208 #define GDATA_SEL 2 /* Kernel Data Descriptor */ 209 #define GLDT_SEL 3 /* LDT - eventually one per process */ 210 #define GTGATE_SEL 4 /* Process task switch gate */ 211 #define GPANIC_SEL 5 /* Task state to consider panic from */ 212 #define GPROC0_SEL 6 /* Task state process slot zero and up */ 213 #define GUSERLDT_SEL 7 /* User LDT */ 214 #define NGDT GUSERLDT_SEL+1 215 216 /* 217 * Entries in the Local Descriptor Table (LDT) 218 */ 219 #define LSYS5CALLS_SEL 0 /* forced by intel BCS */ 220 #define LSYS5SIGR_SEL 1 221 #define L43BSDCALLS_SEL 2 /* notyet */ 222 #define LUCODE_SEL 3 223 #define LUDATA_SEL 4 224 /* seperate stack, es,fs,gs sels ? */ 225 /* #define LPOSIXCALLS_SEL 5*/ /* notyet */ 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 #endif 234 235 #endif /* _MACHINE_SEGMENTS_H_ */ 236