1 /* $OpenBSD: segments.h,v 1.20 2011/03/23 16:54:35 pirofti 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. 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 * @(#)segments.h 7.1 (Berkeley) 5/9/91 38 */ 39 40 /* 41 * 386 Segmentation Data Structures and definitions 42 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 43 */ 44 45 #ifndef _MACHINE_SEGMENTS_H_ 46 #define _MACHINE_SEGMENTS_H_ 47 48 /* 49 * Selectors 50 */ 51 52 #define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */ 53 #define SEL_KPL 0 /* kernel privilege level */ 54 #define SEL_UPL 3 /* user privilege level */ 55 #define SEL_RPL 3 /* requester's privilege level mask */ 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 GSEL(s,r) (((s) << 3) | r) /* a global selector */ 60 #define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */ 61 62 #ifdef VM86 63 #define USERMODE(c, f) (ISPL(c) == SEL_UPL || ((f) & PSL_VM) != 0) 64 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL && ((f) & PSL_VM) == 0) 65 #else 66 #define USERMODE(c, f) (ISPL(c) == SEL_UPL) 67 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL) 68 #endif 69 70 #ifndef _LOCORE 71 72 /* 73 * Memory and System segment descriptors 74 */ 75 struct segment_descriptor { 76 unsigned sd_lolimit:16; /* segment extent (lsb) */ 77 unsigned sd_lobase:24; /* segment base address (lsb) */ 78 unsigned sd_type:5; /* segment type */ 79 unsigned sd_dpl:2; /* segment descriptor priority level */ 80 unsigned sd_p:1; /* segment descriptor present */ 81 unsigned sd_hilimit:4; /* segment extent (msb) */ 82 unsigned sd_xx:2; /* unused */ 83 unsigned sd_def32:1; /* default 32 vs 16 bit size */ 84 unsigned sd_gran:1; /* limit granularity (byte/page) */ 85 unsigned sd_hibase:8; /* segment base address (msb) */ 86 } __packed; 87 88 /* 89 * Gate descriptors (e.g. indirect descriptors) 90 */ 91 struct gate_descriptor { 92 unsigned gd_looffset:16; /* gate offset (lsb) */ 93 unsigned gd_selector:16; /* gate segment selector */ 94 unsigned gd_stkcpy:5; /* number of stack wds to cpy */ 95 unsigned gd_xx:3; /* unused */ 96 unsigned gd_type:5; /* segment type */ 97 unsigned gd_dpl:2; /* segment descriptor priority level */ 98 unsigned gd_p:1; /* segment descriptor present */ 99 unsigned gd_hioffset:16; /* gate offset (msb) */ 100 } __packed; 101 102 /* 103 * Generic descriptor 104 */ 105 union descriptor { 106 struct segment_descriptor sd; 107 struct gate_descriptor gd; 108 } __packed; 109 110 /* 111 * region descriptors, used to load gdt/idt tables before segments yet exist. 112 */ 113 struct region_descriptor { 114 unsigned rd_limit:16; /* segment extent */ 115 unsigned rd_base:32; /* base address */ 116 } __packed; 117 118 #ifdef _KERNEL 119 extern union descriptor *gdt, ldt[]; 120 extern struct gate_descriptor idt_region[]; 121 extern struct gate_descriptor *idt; 122 123 void setgate(struct gate_descriptor *, void *, int, int, int, int); 124 void setregion(struct region_descriptor *, void *, size_t); 125 void setsegment(struct segment_descriptor *, void *, size_t, int, int, 126 int, int); 127 void unsetgate(struct gate_descriptor *); 128 void cpu_init_idt(void); 129 void cpu_default_ldt(struct cpu_info *); 130 void cpu_alloc_ldt(struct cpu_info *); 131 void cpu_init_ldt(struct cpu_info *); 132 133 int idt_vec_alloc(int, int); 134 void idt_vec_set(int, void (*)(void)); 135 void idt_vec_free(int); 136 137 #endif /* _KERNEL */ 138 139 #endif /* !_LOCORE */ 140 141 /* system segments and gate types */ 142 #define SDT_SYSNULL 0 /* system null */ 143 #define SDT_SYS286TSS 1 /* system 286 TSS available */ 144 #define SDT_SYSLDT 2 /* system local descriptor table */ 145 #define SDT_SYS286BSY 3 /* system 286 TSS busy */ 146 #define SDT_SYS286CGT 4 /* system 286 call gate */ 147 #define SDT_SYSTASKGT 5 /* system task gate */ 148 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 149 #define SDT_SYS286TGT 7 /* system 286 trap gate */ 150 #define SDT_SYSNULL2 8 /* system null again */ 151 #define SDT_SYS386TSS 9 /* system 386 TSS available */ 152 #define SDT_SYSNULL3 10 /* system null again */ 153 #define SDT_SYS386BSY 11 /* system 386 TSS busy */ 154 #define SDT_SYS386CGT 12 /* system 386 call gate */ 155 #define SDT_SYSNULL4 13 /* system null again */ 156 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 157 #define SDT_SYS386TGT 15 /* system 386 trap gate */ 158 159 /* memory segment types */ 160 #define SDT_MEMRO 16 /* memory read only */ 161 #define SDT_MEMROA 17 /* memory read only accessed */ 162 #define SDT_MEMRW 18 /* memory read write */ 163 #define SDT_MEMRWA 19 /* memory read write accessed */ 164 #define SDT_MEMROD 20 /* memory read only expand dwn limit */ 165 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 166 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 167 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 168 #define SDT_MEME 24 /* memory execute only */ 169 #define SDT_MEMEA 25 /* memory execute only accessed */ 170 #define SDT_MEMER 26 /* memory execute read */ 171 #define SDT_MEMERA 27 /* memory execute read accessed */ 172 #define SDT_MEMEC 28 /* memory execute only conforming */ 173 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 174 #define SDT_MEMERC 30 /* memory execute read conforming */ 175 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 176 177 /* is memory segment descriptor pointer ? */ 178 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \ 179 (s->d_type) <= SDT_MEMERAC) 180 181 /* is 286 gate descriptor pointer ? */ 182 #define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \ 183 (s->d_type) < SDT_SYS286TGT) 184 185 /* is 386 gate descriptor pointer ? */ 186 #define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \ 187 (s->d_type) < SDT_SYS386TGT) 188 189 /* is gate descriptor pointer ? */ 190 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 191 192 /* is segment descriptor pointer ? */ 193 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 194 195 /* is system segment descriptor pointer ? */ 196 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 197 198 /* 199 * Segment Protection Exception code bits 200 */ 201 #define SEGEX_EXT 0x01 /* recursive or externally induced */ 202 #define SEGEX_IDT 0x02 /* interrupt descriptor table */ 203 #define SEGEX_TI 0x04 /* local descriptor table */ 204 205 /* 206 * Entries in the Interrupt Descriptor Table (IDT) 207 */ 208 #define NIDT 256 209 #define NRSVIDT 32 /* reserved entries for cpu exceptions */ 210 211 /* 212 * Entries in the Global Descriptor Table (GDT) 213 */ 214 #define GNULL_SEL 0 /* Null descriptor */ 215 #define GCODE_SEL 1 /* Kernel code descriptor */ 216 #define GDATA_SEL 2 /* Kernel data descriptor */ 217 #define GLDT_SEL 3 /* Default LDT descriptor */ 218 #define GCPU_SEL 4 /* per-CPU segment */ 219 #define GUCODE_SEL 5 /* User code descriptor (a stack short) */ 220 #define GUDATA_SEL 6 /* User data descriptor */ 221 #define GAPM32CODE_SEL 7 /* 32 bit APM code descriptor */ 222 #define GAPM16CODE_SEL 8 /* 16 bit APM code descriptor */ 223 #define GAPMDATA_SEL 9 /* APM data descriptor */ 224 #define GICODE_SEL 10 /* Interrupt code descriptor (same as Kernel code) */ 225 #define GUFS_SEL 11 /* User per-thread (%fs) descriptor */ 226 #define GUGS_SEL 12 /* User per-thread (%gs) descriptor */ 227 #define NGDT 13 228 229 /* 230 * Entries in the Local Descriptor Table (LDT) 231 */ 232 #define NLDT 17 233 234 #endif /* _MACHINE_SEGMENTS_H_ */ 235