segments.h revision 621
1169689Skan/*- 2169689Skan * Copyright (c) 1989, 1990 William F. Jolitz 3169689Skan * Copyright (c) 1990 The Regents of the University of California. 4169689Skan * All rights reserved. 5169689Skan * 6169689Skan * This code is derived from software contributed to Berkeley by 7169689Skan * William Jolitz. 8169689Skan * 9169689Skan * Redistribution and use in source and binary forms, with or without 10169689Skan * modification, are permitted provided that the following conditions 11169689Skan * are met: 12169689Skan * 1. Redistributions of source code must retain the above copyright 13169689Skan * notice, this list of conditions and the following disclaimer. 14169689Skan * 2. Redistributions in binary form must reproduce the above copyright 15169689Skan * notice, this list of conditions and the following disclaimer in the 16169689Skan * documentation and/or other materials provided with the distribution. 17169689Skan * 3. All advertising materials mentioning features or use of this software 18169689Skan * must display the following acknowledgement: 19169689Skan * This product includes software developed by the University of 20169689Skan * California, Berkeley and its contributors. 21169689Skan * 4. Neither the name of the University nor the names of its contributors 22169689Skan * may be used to endorse or promote products derived from this software 23169689Skan * without specific prior written permission. 24169689Skan * 25169689Skan * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26169689Skan * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27169689Skan * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28169689Skan * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29169689Skan * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30169689Skan * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31169689Skan * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32169689Skan * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33169689Skan * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34169689Skan * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35169689Skan * SUCH DAMAGE. 36169689Skan * 37169689Skan * from: @(#)segments.h 7.1 (Berkeley) 5/9/91 38169689Skan * $Id$ 39169689Skan */ 40169689Skan 41169689Skan/* 42169689Skan * 386 Segmentation Data Structures and definitions 43169689Skan * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 44169689Skan */ 45169689Skan 46169689Skan/* 47169689Skan * Selectors 48169689Skan */ 49169689Skan 50169689Skan#define ISPL(s) ((s)&3) /* what is the priority level of a selector */ 51169689Skan#define SEL_KPL 0 /* kernel priority level */ 52169689Skan#define SEL_UPL 3 /* user priority level */ 53169689Skan#define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */ 54169689Skan#define SEL_LDT 4 /* local descriptor table */ 55169689Skan#define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */ 56169689Skan#define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */ 57169689Skan#define GSEL(s,r) (((s)<<3) | r) /* a global selector */ 58169689Skan 59169689Skan/* 60169689Skan * Memory and System segment descriptors 61169689Skan */ 62169689Skanstruct segment_descriptor { 63169689Skan unsigned sd_lolimit:16 ; /* segment extent (lsb) */ 64169689Skan unsigned sd_lobase:24 ; /* segment base address (lsb) */ 65169689Skan unsigned sd_type:5 ; /* segment type */ 66169689Skan unsigned sd_dpl:2 ; /* segment descriptor priority level */ 67169689Skan unsigned sd_p:1 ; /* segment descriptor present */ 68169689Skan unsigned sd_hilimit:4 ; /* segment extent (msb) */ 69169689Skan unsigned sd_xx:2 ; /* unused */ 70169689Skan unsigned sd_def32:1 ; /* default 32 vs 16 bit size */ 71169689Skan unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/ 72169689Skan unsigned sd_hibase:8 ; /* segment base address (msb) */ 73169689Skan} ; 74169689Skan 75169689Skan/* 76169689Skan * Gate descriptors (e.g. indirect descriptors) 77169689Skan */ 78169689Skanstruct gate_descriptor { 79169689Skan unsigned gd_looffset:16 ; /* gate offset (lsb) */ 80169689Skan unsigned gd_selector:16 ; /* gate segment selector */ 81169689Skan unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */ 82169689Skan unsigned gd_xx:3 ; /* unused */ 83169689Skan unsigned gd_type:5 ; /* segment type */ 84169689Skan unsigned gd_dpl:2 ; /* segment descriptor priority level */ 85169689Skan unsigned gd_p:1 ; /* segment descriptor present */ 86169689Skan unsigned gd_hioffset:16 ; /* gate offset (msb) */ 87169689Skan} ; 88169689Skan 89169689Skan/* 90169689Skan * Generic descriptor 91169689Skan */ 92169689Skanunion descriptor { 93169689Skan struct segment_descriptor sd; 94169689Skan struct gate_descriptor gd; 95169689Skan}; 96169689Skan 97169689Skan /* system segments and gate types */ 98169689Skan#define SDT_SYSNULL 0 /* system null */ 99169689Skan#define SDT_SYS286TSS 1 /* system 286 TSS available */ 100169689Skan#define SDT_SYSLDT 2 /* system local descriptor table */ 101169689Skan#define SDT_SYS286BSY 3 /* system 286 TSS busy */ 102169689Skan#define SDT_SYS286CGT 4 /* system 286 call gate */ 103169689Skan#define SDT_SYSTASKGT 5 /* system task gate */ 104169689Skan#define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 105169689Skan#define SDT_SYS286TGT 7 /* system 286 trap gate */ 106169689Skan#define SDT_SYSNULL2 8 /* system null again */ 107169689Skan#define SDT_SYS386TSS 9 /* system 386 TSS available */ 108169689Skan#define SDT_SYSNULL3 10 /* system null again */ 109169689Skan#define SDT_SYS386BSY 11 /* system 386 TSS busy */ 110169689Skan#define SDT_SYS386CGT 12 /* system 386 call gate */ 111169689Skan#define SDT_SYSNULL4 13 /* system null again */ 112169689Skan#define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 113169689Skan#define SDT_SYS386TGT 15 /* system 386 trap gate */ 114169689Skan 115169689Skan /* memory segment types */ 116169689Skan#define SDT_MEMRO 16 /* memory read only */ 117169689Skan#define SDT_MEMROA 17 /* memory read only accessed */ 118169689Skan#define SDT_MEMRW 18 /* memory read write */ 119169689Skan#define SDT_MEMRWA 19 /* memory read write accessed */ 120169689Skan#define SDT_MEMROD 20 /* memory read only expand dwn limit */ 121169689Skan#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 122169689Skan#define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 123169689Skan#define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 124169689Skan#define SDT_MEME 24 /* memory execute only */ 125169689Skan#define SDT_MEMEA 25 /* memory execute only accessed */ 126169689Skan#define SDT_MEMER 26 /* memory execute read */ 127169689Skan#define SDT_MEMERA 27 /* memory execute read accessed */ 128169689Skan#define SDT_MEMEC 28 /* memory execute only conforming */ 129169689Skan#define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 130169689Skan#define SDT_MEMERC 30 /* memory execute read conforming */ 131169689Skan#define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 132169689Skan 133169689Skan/* is memory segment descriptor pointer ? */ 134169689Skan#define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC) 135169689Skan 136169689Skan/* is 286 gate descriptor pointer ? */ 137169689Skan#define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \ 138169689Skan && (s->d_type) < SDT_SYS286TGT)) 139169689Skan 140169689Skan/* is 386 gate descriptor pointer ? */ 141169689Skan#define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \ 142169689Skan && (s->d_type) < SDT_SYS386TGT)) 143169689Skan 144169689Skan/* is gate descriptor pointer ? */ 145169689Skan#define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 146169689Skan 147169689Skan/* is segment descriptor pointer ? */ 148169689Skan#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 149169689Skan 150169689Skan/* is system segment descriptor pointer ? */ 151169689Skan#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 152169689Skan 153169689Skan/* 154169689Skan * Software definitions are in this convenient format, 155169689Skan * which are translated into inconvenient segment descriptors 156169689Skan * when needed to be used by the 386 hardware 157169689Skan */ 158169689Skan 159169689Skanstruct soft_segment_descriptor { 160169689Skan unsigned ssd_base ; /* segment base address */ 161169689Skan unsigned ssd_limit ; /* segment extent */ 162169689Skan unsigned ssd_type:5 ; /* segment type */ 163169689Skan unsigned ssd_dpl:2 ; /* segment descriptor priority level */ 164169689Skan unsigned ssd_p:1 ; /* segment descriptor present */ 165169689Skan unsigned ssd_xx:4 ; /* unused */ 166169689Skan unsigned ssd_xx1:2 ; /* unused */ 167169689Skan unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */ 168169689Skan unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/ 169169689Skan}; 170169689Skan 171169689Skanextern ssdtosd() ; /* to decode a ssd */ 172169689Skanextern sdtossd() ; /* to encode a sd */ 173169689Skan 174169689Skan/* 175169689Skan * region descriptors, used to load gdt/idt tables before segments yet exist. 176169689Skan */ 177169689Skanstruct region_descriptor { 178169689Skan unsigned rd_limit:16; /* segment extent */ 179169689Skan unsigned rd_base:32; /* base address */ 180169689Skan}; 181169689Skan 182169689Skan/* 183169689Skan * Segment Protection Exception code bits 184169689Skan */ 185169689Skan 186169689Skan#define SEGEX_EXT 0x01 /* recursive or externally induced */ 187169689Skan#define SEGEX_IDT 0x02 /* interrupt descriptor table */ 188169689Skan#define SEGEX_TI 0x04 /* local descriptor table */ 189169689Skan /* other bits are affected descriptor index */ 190169689Skan#define SEGEX_IDX(s) ((s)>>3)&0x1fff) 191169689Skan 192169689Skan/* 193169689Skan * Size of IDT table 194169689Skan */ 195169689Skan 196169689Skan#define NIDT 256 197169689Skan#define NRSVIDT 32 /* reserved entries for cpu exceptions */ 198169689Skan