segments.h revision 4
14Srgrimes/*- 24Srgrimes * Copyright (c) 1989, 1990 William F. Jolitz 34Srgrimes * Copyright (c) 1990 The Regents of the University of California. 44Srgrimes * All rights reserved. 54Srgrimes * 64Srgrimes * This code is derived from software contributed to Berkeley by 74Srgrimes * William Jolitz. 84Srgrimes * 94Srgrimes * Redistribution and use in source and binary forms, with or without 104Srgrimes * modification, are permitted provided that the following conditions 114Srgrimes * are met: 124Srgrimes * 1. Redistributions of source code must retain the above copyright 134Srgrimes * notice, this list of conditions and the following disclaimer. 144Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 154Srgrimes * notice, this list of conditions and the following disclaimer in the 164Srgrimes * documentation and/or other materials provided with the distribution. 174Srgrimes * 3. All advertising materials mentioning features or use of this software 184Srgrimes * must display the following acknowledgement: 194Srgrimes * This product includes software developed by the University of 204Srgrimes * California, Berkeley and its contributors. 214Srgrimes * 4. Neither the name of the University nor the names of its contributors 224Srgrimes * may be used to endorse or promote products derived from this software 234Srgrimes * without specific prior written permission. 244Srgrimes * 254Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 264Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 274Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 284Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 294Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 304Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 314Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 324Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 334Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 344Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 354Srgrimes * SUCH DAMAGE. 364Srgrimes * 374Srgrimes * @(#)segments.h 7.1 (Berkeley) 5/9/91 384Srgrimes */ 394Srgrimes 404Srgrimes/* 414Srgrimes * 386 Segmentation Data Structures and definitions 424Srgrimes * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 434Srgrimes */ 444Srgrimes 454Srgrimes/* 464Srgrimes * Selectors 474Srgrimes */ 484Srgrimes 494Srgrimes#define ISPL(s) ((s)&3) /* what is the priority level of a selector */ 504Srgrimes#define SEL_KPL 0 /* kernel priority level */ 514Srgrimes#define SEL_UPL 3 /* user priority level */ 524Srgrimes#define ISLDT(s) ((s)&SEL_LDT) /* is it local or global */ 534Srgrimes#define SEL_LDT 4 /* local descriptor table */ 544Srgrimes#define IDXSEL(s) (((s)>>3) & 0x1fff) /* index of selector */ 554Srgrimes#define LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */ 564Srgrimes#define GSEL(s,r) (((s)<<3) | r) /* a global selector */ 574Srgrimes 584Srgrimes/* 594Srgrimes * Memory and System segment descriptors 604Srgrimes */ 614Srgrimesstruct segment_descriptor { 624Srgrimes unsigned sd_lolimit:16 ; /* segment extent (lsb) */ 634Srgrimes unsigned sd_lobase:24 ; /* segment base address (lsb) */ 644Srgrimes unsigned sd_type:5 ; /* segment type */ 654Srgrimes unsigned sd_dpl:2 ; /* segment descriptor priority level */ 664Srgrimes unsigned sd_p:1 ; /* segment descriptor present */ 674Srgrimes unsigned sd_hilimit:4 ; /* segment extent (msb) */ 684Srgrimes unsigned sd_xx:2 ; /* unused */ 694Srgrimes unsigned sd_def32:1 ; /* default 32 vs 16 bit size */ 704Srgrimes unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/ 714Srgrimes unsigned sd_hibase:8 ; /* segment base address (msb) */ 724Srgrimes} ; 734Srgrimes 744Srgrimes/* 754Srgrimes * Gate descriptors (e.g. indirect descriptors) 764Srgrimes */ 774Srgrimesstruct gate_descriptor { 784Srgrimes unsigned gd_looffset:16 ; /* gate offset (lsb) */ 794Srgrimes unsigned gd_selector:16 ; /* gate segment selector */ 804Srgrimes unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */ 814Srgrimes unsigned gd_xx:3 ; /* unused */ 824Srgrimes unsigned gd_type:5 ; /* segment type */ 834Srgrimes unsigned gd_dpl:2 ; /* segment descriptor priority level */ 844Srgrimes unsigned gd_p:1 ; /* segment descriptor present */ 854Srgrimes unsigned gd_hioffset:16 ; /* gate offset (msb) */ 864Srgrimes} ; 874Srgrimes 884Srgrimes/* 894Srgrimes * Generic descriptor 904Srgrimes */ 914Srgrimesunion descriptor { 924Srgrimes struct segment_descriptor sd; 934Srgrimes struct gate_descriptor gd; 944Srgrimes}; 954Srgrimes 964Srgrimes /* system segments and gate types */ 974Srgrimes#define SDT_SYSNULL 0 /* system null */ 984Srgrimes#define SDT_SYS286TSS 1 /* system 286 TSS available */ 994Srgrimes#define SDT_SYSLDT 2 /* system local descriptor table */ 1004Srgrimes#define SDT_SYS286BSY 3 /* system 286 TSS busy */ 1014Srgrimes#define SDT_SYS286CGT 4 /* system 286 call gate */ 1024Srgrimes#define SDT_SYSTASKGT 5 /* system task gate */ 1034Srgrimes#define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 1044Srgrimes#define SDT_SYS286TGT 7 /* system 286 trap gate */ 1054Srgrimes#define SDT_SYSNULL2 8 /* system null again */ 1064Srgrimes#define SDT_SYS386TSS 9 /* system 386 TSS available */ 1074Srgrimes#define SDT_SYSNULL3 10 /* system null again */ 1084Srgrimes#define SDT_SYS386BSY 11 /* system 386 TSS busy */ 1094Srgrimes#define SDT_SYS386CGT 12 /* system 386 call gate */ 1104Srgrimes#define SDT_SYSNULL4 13 /* system null again */ 1114Srgrimes#define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 1124Srgrimes#define SDT_SYS386TGT 15 /* system 386 trap gate */ 1134Srgrimes 1144Srgrimes /* memory segment types */ 1154Srgrimes#define SDT_MEMRO 16 /* memory read only */ 1164Srgrimes#define SDT_MEMROA 17 /* memory read only accessed */ 1174Srgrimes#define SDT_MEMRW 18 /* memory read write */ 1184Srgrimes#define SDT_MEMRWA 19 /* memory read write accessed */ 1194Srgrimes#define SDT_MEMROD 20 /* memory read only expand dwn limit */ 1204Srgrimes#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 1214Srgrimes#define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 1224Srgrimes#define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 1234Srgrimes#define SDT_MEME 24 /* memory execute only */ 1244Srgrimes#define SDT_MEMEA 25 /* memory execute only accessed */ 1254Srgrimes#define SDT_MEMER 26 /* memory execute read */ 1264Srgrimes#define SDT_MEMERA 27 /* memory execute read accessed */ 1274Srgrimes#define SDT_MEMEC 28 /* memory execute only conforming */ 1284Srgrimes#define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 1294Srgrimes#define SDT_MEMERC 30 /* memory execute read conforming */ 1304Srgrimes#define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 1314Srgrimes 1324Srgrimes/* is memory segment descriptor pointer ? */ 1334Srgrimes#define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC) 1344Srgrimes 1354Srgrimes/* is 286 gate descriptor pointer ? */ 1364Srgrimes#define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \ 1374Srgrimes && (s->d_type) < SDT_SYS286TGT)) 1384Srgrimes 1394Srgrimes/* is 386 gate descriptor pointer ? */ 1404Srgrimes#define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \ 1414Srgrimes && (s->d_type) < SDT_SYS386TGT)) 1424Srgrimes 1434Srgrimes/* is gate descriptor pointer ? */ 1444Srgrimes#define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 1454Srgrimes 1464Srgrimes/* is segment descriptor pointer ? */ 1474Srgrimes#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 1484Srgrimes 1494Srgrimes/* is system segment descriptor pointer ? */ 1504Srgrimes#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 1514Srgrimes 1524Srgrimes/* 1534Srgrimes * Software definitions are in this convenient format, 1544Srgrimes * which are translated into inconvenient segment descriptors 1554Srgrimes * when needed to be used by the 386 hardware 1564Srgrimes */ 1574Srgrimes 1584Srgrimesstruct soft_segment_descriptor { 1594Srgrimes unsigned ssd_base ; /* segment base address */ 1604Srgrimes unsigned ssd_limit ; /* segment extent */ 1614Srgrimes unsigned ssd_type:5 ; /* segment type */ 1624Srgrimes unsigned ssd_dpl:2 ; /* segment descriptor priority level */ 1634Srgrimes unsigned ssd_p:1 ; /* segment descriptor present */ 1644Srgrimes unsigned ssd_xx:4 ; /* unused */ 1654Srgrimes unsigned ssd_xx1:2 ; /* unused */ 1664Srgrimes unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */ 1674Srgrimes unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/ 1684Srgrimes}; 1694Srgrimes 1704Srgrimesextern ssdtosd() ; /* to decode a ssd */ 1714Srgrimesextern sdtossd() ; /* to encode a sd */ 1724Srgrimes 1734Srgrimes/* 1744Srgrimes * region descriptors, used to load gdt/idt tables before segments yet exist. 1754Srgrimes */ 1764Srgrimesstruct region_descriptor { 1774Srgrimes unsigned rd_limit:16; /* segment extent */ 1784Srgrimes unsigned rd_base:32; /* base address */ 1794Srgrimes}; 1804Srgrimes 1814Srgrimes/* 1824Srgrimes * Segment Protection Exception code bits 1834Srgrimes */ 1844Srgrimes 1854Srgrimes#define SEGEX_EXT 0x01 /* recursive or externally induced */ 1864Srgrimes#define SEGEX_IDT 0x02 /* interrupt descriptor table */ 1874Srgrimes#define SEGEX_TI 0x04 /* local descriptor table */ 1884Srgrimes /* other bits are affected descriptor index */ 1894Srgrimes#define SEGEX_IDX(s) ((s)>>3)&0x1fff) 1904Srgrimes 1914Srgrimes/* 1924Srgrimes * Size of IDT table 1934Srgrimes */ 1944Srgrimes 1954Srgrimes#define NIDT 256 1964Srgrimes#define NRSVIDT 32 /* reserved entries for cpu exceptions */ 197