1 /* $OpenBSD: segments.h,v 1.8 2000/12/06 17:18:58 deraadt Exp $ */ 2 /* $NetBSD: segments.h,v 1.23 1996/02/01 22:31:03 mycroft Exp $ */ 3 4 /*- 5 * Copyright (c) 1995 Charles M. Hannum. All rights reserved. 6 * Copyright (c) 1989, 1990 William F. Jolitz 7 * Copyright (c) 1990 The Regents of the University of California. 8 * All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * William Jolitz. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)segments.h 7.1 (Berkeley) 5/9/91 42 */ 43 44 /* 45 * 386 Segmentation Data Structures and definitions 46 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 47 */ 48 49 #ifndef _I386_SEGMENTS_H_ 50 #define _I386_SEGMENTS_H_ 51 52 /* 53 * Selectors 54 */ 55 56 #define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */ 57 #define SEL_KPL 0 /* kernel privilege level */ 58 #define SEL_UPL 3 /* user privilege level */ 59 #define SEL_RPL 3 /* requester's privilege level mask */ 60 #define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */ 61 #define SEL_LDT 4 /* local descriptor table */ 62 #define IDXSEL(s) (((s) >> 3) & 0x1fff) /* index of selector */ 63 #define GSEL(s,r) (((s) << 3) | r) /* a global selector */ 64 #define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */ 65 66 #ifdef VM86 67 #define USERMODE(c, f) (ISPL(c) == SEL_UPL || ((f) & PSL_VM) != 0) 68 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL && ((f) & PSL_VM) == 0) 69 #else 70 #define USERMODE(c, f) (ISPL(c) == SEL_UPL) 71 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL) 72 #endif 73 74 #ifndef _LOCORE 75 76 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7 77 #pragma pack(1) 78 #endif 79 80 /* 81 * Memory and System segment descriptors 82 */ 83 struct segment_descriptor { 84 unsigned sd_lolimit:16; /* segment extent (lsb) */ 85 unsigned sd_lobase:24; /* segment base address (lsb) */ 86 unsigned sd_type:5; /* segment type */ 87 unsigned sd_dpl:2; /* segment descriptor priority level */ 88 unsigned sd_p:1; /* segment descriptor present */ 89 unsigned sd_hilimit:4; /* segment extent (msb) */ 90 unsigned sd_xx:2; /* unused */ 91 unsigned sd_def32:1; /* default 32 vs 16 bit size */ 92 unsigned sd_gran:1; /* limit granularity (byte/page) */ 93 unsigned sd_hibase:8; /* segment base address (msb) */ 94 } __attribute__((__packed__)); 95 96 /* 97 * Gate descriptors (e.g. indirect descriptors) 98 */ 99 struct gate_descriptor { 100 unsigned gd_looffset:16; /* gate offset (lsb) */ 101 unsigned gd_selector:16; /* gate segment selector */ 102 unsigned gd_stkcpy:5; /* number of stack wds to cpy */ 103 unsigned gd_xx:3; /* unused */ 104 unsigned gd_type:5; /* segment type */ 105 unsigned gd_dpl:2; /* segment descriptor priority level */ 106 unsigned gd_p:1; /* segment descriptor present */ 107 unsigned gd_hioffset:16; /* gate offset (msb) */ 108 } __attribute__((__packed__)); 109 110 /* 111 * Generic descriptor 112 */ 113 union descriptor { 114 struct segment_descriptor sd; 115 struct gate_descriptor gd; 116 } __attribute__((__packed__)); 117 118 /* 119 * region descriptors, used to load gdt/idt tables before segments yet exist. 120 */ 121 struct region_descriptor { 122 unsigned rd_limit:16; /* segment extent */ 123 unsigned rd_base:32; /* base address */ 124 } __attribute__((__packed__)); 125 126 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7 127 #pragma pack(4) 128 #endif 129 130 #ifdef _KERNEL 131 extern union descriptor gdt[], ldt[]; 132 extern struct gate_descriptor idt_region[]; 133 extern struct gate_descriptor *idt; 134 135 void setgate __P((struct gate_descriptor *, void *, int, int, int, int)); 136 void setregion __P((struct region_descriptor *, void *, size_t)); 137 void setsegment __P((struct segment_descriptor *, void *, size_t, int, int, 138 int, int)); 139 #endif /* _KERNEL */ 140 141 #endif /* !_LOCORE */ 142 143 /* system segments and gate types */ 144 #define SDT_SYSNULL 0 /* system null */ 145 #define SDT_SYS286TSS 1 /* system 286 TSS available */ 146 #define SDT_SYSLDT 2 /* system local descriptor table */ 147 #define SDT_SYS286BSY 3 /* system 286 TSS busy */ 148 #define SDT_SYS286CGT 4 /* system 286 call gate */ 149 #define SDT_SYSTASKGT 5 /* system task gate */ 150 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 151 #define SDT_SYS286TGT 7 /* system 286 trap gate */ 152 #define SDT_SYSNULL2 8 /* system null again */ 153 #define SDT_SYS386TSS 9 /* system 386 TSS available */ 154 #define SDT_SYSNULL3 10 /* system null again */ 155 #define SDT_SYS386BSY 11 /* system 386 TSS busy */ 156 #define SDT_SYS386CGT 12 /* system 386 call gate */ 157 #define SDT_SYSNULL4 13 /* system null again */ 158 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 159 #define SDT_SYS386TGT 15 /* system 386 trap gate */ 160 161 /* memory segment types */ 162 #define SDT_MEMRO 16 /* memory read only */ 163 #define SDT_MEMROA 17 /* memory read only accessed */ 164 #define SDT_MEMRW 18 /* memory read write */ 165 #define SDT_MEMRWA 19 /* memory read write accessed */ 166 #define SDT_MEMROD 20 /* memory read only expand dwn limit */ 167 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 168 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 169 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 170 #define SDT_MEME 24 /* memory execute only */ 171 #define SDT_MEMEA 25 /* memory execute only accessed */ 172 #define SDT_MEMER 26 /* memory execute read */ 173 #define SDT_MEMERA 27 /* memory execute read accessed */ 174 #define SDT_MEMEC 28 /* memory execute only conforming */ 175 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 176 #define SDT_MEMERC 30 /* memory execute read conforming */ 177 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 178 179 /* is memory segment descriptor pointer ? */ 180 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \ 181 (s->d_type) <= SDT_MEMERAC) 182 183 /* is 286 gate descriptor pointer ? */ 184 #define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \ 185 (s->d_type) < SDT_SYS286TGT) 186 187 /* is 386 gate descriptor pointer ? */ 188 #define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \ 189 (s->d_type) < SDT_SYS386TGT) 190 191 /* is gate descriptor pointer ? */ 192 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 193 194 /* is segment descriptor pointer ? */ 195 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 196 197 /* is system segment descriptor pointer ? */ 198 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 199 200 /* 201 * Segment Protection Exception code bits 202 */ 203 #define SEGEX_EXT 0x01 /* recursive or externally induced */ 204 #define SEGEX_IDT 0x02 /* interrupt descriptor table */ 205 #define SEGEX_TI 0x04 /* local descriptor table */ 206 207 /* 208 * Entries in the Interrupt Descriptor Table (IDT) 209 */ 210 #define NIDT 256 211 #define NRSVIDT 32 /* reserved entries for cpu exceptions */ 212 213 /* 214 * Entries in the Global Descriptor Table (GDT) 215 */ 216 #define GNULL_SEL 0 /* Null descriptor */ 217 #define GCODE_SEL 1 /* Kernel code descriptor */ 218 #define GDATA_SEL 2 /* Kernel data descriptor */ 219 #define GLDT_SEL 3 /* Default LDT descriptor */ 220 #define GUCODE_SEL 4 /* User code descriptor */ 221 #define GUDATA_SEL 5 /* User data descriptor */ 222 #define GAPM32CODE_SEL 6 /* 32 bit APM code descriptor */ 223 #define GAPM16CODE_SEL 7 /* 16 bit APM code descriptor */ 224 #define GAPMDATA_SEL 8 /* APM data descriptor */ 225 #define GICODE_SEL 9 /* Interrupt code descriptor (same as Kernel code) */ 226 #define NGDT 10 227 228 /* 229 * Entries in the Local Descriptor Table (LDT) 230 */ 231 #define LSYS5CALLS_SEL 0 /* iBCS system call gate */ 232 #define LSYS5SIGR_SEL 1 /* iBCS sigreturn gate */ 233 #define LUCODE_SEL 2 /* User code descriptor */ 234 #define LUDATA_SEL 3 /* User data descriptor */ 235 #define LBSDICALLS_SEL 16 /* BSDI system call gate */ 236 #define NLDT 17 237 238 #endif /* _I386_SEGMENTS_H_ */ 239