segments.h revision 27519
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 1.1 1997/07/19 01:32:04 smp Exp smp $ 39 */ 40 41#ifndef _MACHINE_SEGMENTS_H_ 42#define _MACHINE_SEGMENTS_H_ 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 */ 65struct 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 */ 82struct 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 */ 96union 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 accessed */ 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 163struct 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/* 176 * region descriptors, used to load gdt/idt tables before segments yet exist. 177 */ 178struct region_descriptor { 179 unsigned rd_limit:16; /* segment extent */ 180 unsigned rd_base:32 __attribute__ ((packed)); /* base address */ 181}; 182 183/* 184 * Segment Protection Exception code bits 185 */ 186 187#define SEGEX_EXT 0x01 /* recursive or externally induced */ 188#define SEGEX_IDT 0x02 /* interrupt descriptor table */ 189#define SEGEX_TI 0x04 /* local descriptor table */ 190 /* other bits are affected descriptor index */ 191#define SEGEX_IDX(s) ((s)>>3)&0x1fff) 192 193/* 194 * Size of IDT table 195 */ 196 197#if defined(SMP) || defined(APIC_IO) 198#define NIDT 256 /* we use them all */ 199#else 200#define NIDT 129 /* 32 reserved, 16 h/w, 0 s/w, linux's 0x80 */ 201#endif /* SMP || APIC_IO */ 202#define NRSVIDT 32 /* reserved entries for cpu exceptions */ 203 204/* 205 * Entries in the Global Descriptor Table (GDT) 206 */ 207#define GNULL_SEL 0 /* Null Descriptor */ 208#define GCODE_SEL 1 /* Kernel Code Descriptor */ 209#define GDATA_SEL 2 /* Kernel Data Descriptor */ 210#define GLDT_SEL 3 /* LDT - eventually one per process */ 211#define GTGATE_SEL 4 /* Process task switch gate */ 212#define GPANIC_SEL 5 /* Task state to consider panic from */ 213#define GPROC0_SEL 6 /* Task state process slot zero and up */ 214#define GUSERLDT_SEL 7 /* User LDT */ 215#define GAPMCODE32_SEL 8 /* APM BIOS 32-bit interface (32bit Code) */ 216#define GAPMCODE16_SEL 9 /* APM BIOS 32-bit interface (16bit Code) */ 217#define GAPMDATA_SEL 10 /* APM BIOS 32-bit interface (Data) */ 218 219#ifdef BDE_DEBUGGER 220#define NGDT 18 /* some of 11-17 are reserved for debugger */ 221#else 222#define NGDT (GAPMDATA_SEL + 1) 223#endif 224 225/* 226 * Entries in the Local Descriptor Table (LDT) 227 */ 228#define LSYS5CALLS_SEL 0 /* forced by intel BCS */ 229#define LSYS5SIGR_SEL 1 230#define L43BSDCALLS_SEL 2 /* notyet */ 231#define LUCODE_SEL 3 232#define LUDATA_SEL 4 233/* separate stack, es,fs,gs sels ? */ 234/* #define LPOSIXCALLS_SEL 5*/ /* notyet */ 235#define LBSDICALLS_SEL 16 /* BSDI system call gate */ 236#define NLDT (LBSDICALLS_SEL + 1) 237 238#ifdef KERNEL 239extern int currentldt; 240extern int _default_ldt; 241extern union descriptor gdt[]; 242extern struct soft_segment_descriptor gdt_segs[]; 243extern struct gate_descriptor idt[NIDT]; 244extern union descriptor ldt[NLDT]; 245 246void lgdt __P((struct region_descriptor *rdp)); 247void lidt __P((struct region_descriptor *rdp)); 248void lldt __P((u_short sel)); 249void sdtossd __P((struct segment_descriptor *sdp, 250 struct soft_segment_descriptor *ssdp)); 251void ssdtosd __P((struct soft_segment_descriptor *ssdp, 252 struct segment_descriptor *sdp)); 253#endif /* KERNEL */ 254 255#endif /* !_MACHINE_SEGMENTS_H_ */ 256