segments.h revision 103847
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 * $FreeBSD: head/sys/i386/include/segments.h 103847 2002-09-23 06:50:07Z peter $ 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 __packed; /* segment base address (lsb) */ 68 unsigned sd_type:5 ; /* segment type */ 69 unsigned sd_dpl:2 ; /* segment descriptor priority level */ 70 unsigned sd_p:1 ; /* segment descriptor present */ 71 unsigned sd_hilimit:4 ; /* segment extent (msb) */ 72 unsigned sd_xx:2 ; /* unused */ 73 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */ 74 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/ 75 unsigned sd_hibase:8 ; /* segment base address (msb) */ 76} ; 77 78/* 79 * Gate descriptors (e.g. indirect descriptors) 80 */ 81struct gate_descriptor { 82 unsigned gd_looffset:16 ; /* gate offset (lsb) */ 83 unsigned gd_selector:16 ; /* gate segment selector */ 84 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */ 85 unsigned gd_xx:3 ; /* unused */ 86 unsigned gd_type:5 ; /* segment type */ 87 unsigned gd_dpl:2 ; /* segment descriptor priority level */ 88 unsigned gd_p:1 ; /* segment descriptor present */ 89 unsigned gd_hioffset:16 ; /* gate offset (msb) */ 90} ; 91 92/* 93 * Generic descriptor 94 */ 95union descriptor { 96 struct segment_descriptor sd; 97 struct gate_descriptor gd; 98}; 99 100 /* system segments and gate types */ 101#define SDT_SYSNULL 0 /* system null */ 102#define SDT_SYS286TSS 1 /* system 286 TSS available */ 103#define SDT_SYSLDT 2 /* system local descriptor table */ 104#define SDT_SYS286BSY 3 /* system 286 TSS busy */ 105#define SDT_SYS286CGT 4 /* system 286 call gate */ 106#define SDT_SYSTASKGT 5 /* system task gate */ 107#define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 108#define SDT_SYS286TGT 7 /* system 286 trap gate */ 109#define SDT_SYSNULL2 8 /* system null again */ 110#define SDT_SYS386TSS 9 /* system 386 TSS available */ 111#define SDT_SYSNULL3 10 /* system null again */ 112#define SDT_SYS386BSY 11 /* system 386 TSS busy */ 113#define SDT_SYS386CGT 12 /* system 386 call gate */ 114#define SDT_SYSNULL4 13 /* system null again */ 115#define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 116#define SDT_SYS386TGT 15 /* system 386 trap gate */ 117 118 /* memory segment types */ 119#define SDT_MEMRO 16 /* memory read only */ 120#define SDT_MEMROA 17 /* memory read only accessed */ 121#define SDT_MEMRW 18 /* memory read write */ 122#define SDT_MEMRWA 19 /* memory read write accessed */ 123#define SDT_MEMROD 20 /* memory read only expand dwn limit */ 124#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 125#define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 126#define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */ 127#define SDT_MEME 24 /* memory execute only */ 128#define SDT_MEMEA 25 /* memory execute only accessed */ 129#define SDT_MEMER 26 /* memory execute read */ 130#define SDT_MEMERA 27 /* memory execute read accessed */ 131#define SDT_MEMEC 28 /* memory execute only conforming */ 132#define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 133#define SDT_MEMERC 30 /* memory execute read conforming */ 134#define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 135 136/* is memory segment descriptor pointer ? */ 137#define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && (s->d_type) <= SDT_MEMERAC) 138 139/* is 286 gate descriptor pointer ? */ 140#define IS286GDP(s) (((s->d_type) >= SDT_SYS286CGT \ 141 && (s->d_type) < SDT_SYS286TGT)) 142 143/* is 386 gate descriptor pointer ? */ 144#define IS386GDP(s) (((s->d_type) >= SDT_SYS386CGT \ 145 && (s->d_type) < SDT_SYS386TGT)) 146 147/* is gate descriptor pointer ? */ 148#define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 149 150/* is segment descriptor pointer ? */ 151#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 152 153/* is system segment descriptor pointer ? */ 154#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 155 156/* 157 * Software definitions are in this convenient format, 158 * which are translated into inconvenient segment descriptors 159 * when needed to be used by the 386 hardware 160 */ 161 162struct soft_segment_descriptor { 163 unsigned ssd_base ; /* segment base address */ 164 unsigned ssd_limit ; /* segment extent */ 165 unsigned ssd_type:5 ; /* segment type */ 166 unsigned ssd_dpl:2 ; /* segment descriptor priority level */ 167 unsigned ssd_p:1 ; /* segment descriptor present */ 168 unsigned ssd_xx:4 ; /* unused */ 169 unsigned ssd_xx1:2 ; /* unused */ 170 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */ 171 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/ 172}; 173 174/* 175 * region descriptors, used to load gdt/idt tables before segments yet exist. 176 */ 177struct region_descriptor { 178 unsigned rd_limit:16; /* segment extent */ 179 unsigned rd_base:32 __packed; /* base address */ 180}; 181 182/* 183 * Segment Protection Exception code bits 184 */ 185 186#define SEGEX_EXT 0x01 /* recursive or externally induced */ 187#define SEGEX_IDT 0x02 /* interrupt descriptor table */ 188#define SEGEX_TI 0x04 /* local descriptor table */ 189 /* other bits are affected descriptor index */ 190#define SEGEX_IDX(s) (((s)>>3)&0x1fff) 191 192/* 193 * Size of IDT table 194 */ 195 196#if defined(SMP) || defined(APIC_IO) 197#define NIDT 256 /* we use them all */ 198#else 199#define NIDT 129 /* 32 reserved, 16 h/w, 0 s/w, linux's 0x80 */ 200#endif /* SMP || APIC_IO */ 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 GPRIV_SEL 3 /* SMP Per-Processor Private Data */ 210#define GPROC0_SEL 4 /* Task state process slot zero and up */ 211#define GLDT_SEL 5 /* LDT - eventually one per process */ 212#define GUSERLDT_SEL 6 /* User LDT */ 213#define GTGATE_SEL 7 /* Process task switch gate */ 214#define GBIOSLOWMEM_SEL 8 /* BIOS low memory access (must be entry 8) */ 215#define GPANIC_SEL 9 /* Task state to consider panic from */ 216#define GBIOSCODE32_SEL 10 /* BIOS interface (32bit Code) */ 217#define GBIOSCODE16_SEL 11 /* BIOS interface (16bit Code) */ 218#define GBIOSDATA_SEL 12 /* BIOS interface (Data) */ 219#define GBIOSUTIL_SEL 13 /* BIOS interface (Utility) */ 220#define GBIOSARGS_SEL 14 /* BIOS interface (Arguments) */ 221 222#ifdef BDE_DEBUGGER 223#define NGDT 18 /* some of 11-17 are reserved for debugger */ 224#else 225#define NGDT 15 226#endif 227 228/* 229 * Entries in the Local Descriptor Table (LDT) 230 */ 231#define LSYS5CALLS_SEL 0 /* forced by intel BCS */ 232#define LSYS5SIGR_SEL 1 233#define L43BSDCALLS_SEL 2 /* notyet */ 234#define LUCODE_SEL 3 235#define LSOL26CALLS_SEL 4 /* Solaris >= 2.6 system call gate */ 236#define LUDATA_SEL 5 237/* separate stack, es,fs,gs sels ? */ 238/* #define LPOSIXCALLS_SEL 5*/ /* notyet */ 239#define LBSDICALLS_SEL 16 /* BSDI system call gate */ 240#define NLDT (LBSDICALLS_SEL + 1) 241 242#ifdef _KERNEL 243extern int _default_ldt; 244extern union descriptor gdt[]; 245extern struct soft_segment_descriptor gdt_segs[]; 246extern struct gate_descriptor *idt; 247extern union descriptor ldt[NLDT]; 248 249void lgdt(struct region_descriptor *rdp); 250void sdtossd(struct segment_descriptor *sdp, 251 struct soft_segment_descriptor *ssdp); 252void ssdtosd(struct soft_segment_descriptor *ssdp, 253 struct segment_descriptor *sdp); 254#endif /* _KERNEL */ 255 256#endif /* !_MACHINE_SEGMENTS_H_ */ 257