1/* $OpenBSD: segments.h,v 1.28 2020/09/24 11:36:50 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. 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#define USERMODE(c, f) (ISPL(c) == SEL_UPL) 63#define KERNELMODE(c, f) (ISPL(c) == SEL_KPL) 64 65#ifndef _LOCORE 66 67/* 68 * Memory and System segment descriptors 69 */ 70struct segment_descriptor { 71 unsigned sd_lolimit:16; /* segment extent (lsb) */ 72 unsigned sd_lobase:24; /* segment base address (lsb) */ 73 unsigned sd_type:5; /* segment type */ 74 unsigned sd_dpl:2; /* segment descriptor priority level */ 75 unsigned sd_p:1; /* segment descriptor present */ 76 unsigned sd_hilimit:4; /* segment extent (msb) */ 77 unsigned sd_xx:2; /* unused */ 78 unsigned sd_def32:1; /* default 32 vs 16 bit size */ 79 unsigned sd_gran:1; /* limit granularity (byte/page) */ 80 unsigned sd_hibase:8; /* segment base address (msb) */ 81} __packed; 82 83/* 84 * Gate descriptors (e.g. indirect descriptors) 85 */ 86struct gate_descriptor { 87 unsigned gd_looffset:16; /* gate offset (lsb) */ 88 unsigned gd_selector:16; /* gate segment selector */ 89 unsigned gd_stkcpy:5; /* number of stack wds to cpy */ 90 unsigned gd_xx:3; /* unused */ 91 unsigned gd_type:5; /* segment type */ 92 unsigned gd_dpl:2; /* segment descriptor priority level */ 93 unsigned gd_p:1; /* segment descriptor present */ 94 unsigned gd_hioffset:16; /* gate offset (msb) */ 95} __packed; 96 97/* 98 * Generic descriptor 99 */ 100union descriptor { 101 struct segment_descriptor sd; 102 struct gate_descriptor gd; 103} __packed; 104 105/* 106 * region descriptors, used to load gdt/idt tables before segments yet exist. 107 */ 108struct region_descriptor { 109 unsigned rd_limit:16; /* segment extent */ 110 unsigned rd_base:32; /* base address */ 111} __packed; 112 113#ifdef _KERNEL 114extern union descriptor *gdt; 115extern struct gate_descriptor idt_region[]; 116extern struct gate_descriptor *idt; 117 118#define SEGDESC_LIMIT(sd) (ptoa(((sd).sd_hilimit << 16) | (sd).sd_lolimit)) 119 120void setgate(struct gate_descriptor *, void *, int, int, int, int); 121void setregion(struct region_descriptor *, void *, size_t); 122void setsegment(struct segment_descriptor *, void *, size_t, int, int, 123 int, int); 124void initcodesegment(struct segment_descriptor *); 125void unsetgate(struct gate_descriptor *); 126void cpu_init_idt(void); 127 128int idt_vec_alloc(int, int); 129void idt_vec_set(int, void (*)(void)); 130void idt_vec_free(int); 131 132#endif /* _KERNEL */ 133 134#endif /* !_LOCORE */ 135 136/* system segments and gate types */ 137#define SDT_SYSNULL 0 /* system null */ 138#define SDT_SYS286TSS 1 /* system 286 TSS available */ 139#define SDT_SYSLDT 2 /* system local descriptor table */ 140#define SDT_SYS286BSY 3 /* system 286 TSS busy */ 141#define SDT_SYS286CGT 4 /* system 286 call gate */ 142#define SDT_SYSTASKGT 5 /* system task gate */ 143#define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 144#define SDT_SYS286TGT 7 /* system 286 trap gate */ 145#define SDT_SYSNULL2 8 /* system null again */ 146#define SDT_SYS386TSS 9 /* system 386 TSS available */ 147#define SDT_SYSNULL3 10 /* system null again */ 148#define SDT_SYS386BSY 11 /* system 386 TSS busy */ 149#define SDT_SYS386CGT 12 /* system 386 call gate */ 150#define SDT_SYSNULL4 13 /* system null again */ 151#define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 152#define SDT_SYS386TGT 15 /* system 386 trap gate */ 153 154/* memory segment types */ 155#define SDT_MEMRO 16 /* memory read only */ 156#define SDT_MEMROA 17 /* memory read only accessed */ 157#define SDT_MEMRW 18 /* memory read write */ 158#define SDT_MEMRWA 19 /* memory read write accessed */ 159#define SDT_MEMROD 20 /* memory read only expand dwn limit */ 160#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 161#define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 162#define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 163#define SDT_MEME 24 /* memory execute only */ 164#define SDT_MEMEA 25 /* memory execute only accessed */ 165#define SDT_MEMER 26 /* memory execute read */ 166#define SDT_MEMERA 27 /* memory execute read accessed */ 167#define SDT_MEMEC 28 /* memory execute only conforming */ 168#define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 169#define SDT_MEMERC 30 /* memory execute read conforming */ 170#define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 171 172/* is memory segment descriptor pointer ? */ 173#define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \ 174 (s->d_type) <= SDT_MEMERAC) 175 176/* is 286 gate descriptor pointer ? */ 177#define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \ 178 (s->d_type) < SDT_SYS286TGT) 179 180/* is 386 gate descriptor pointer ? */ 181#define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \ 182 (s->d_type) < SDT_SYS386TGT) 183 184/* is gate descriptor pointer ? */ 185#define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 186 187/* is segment descriptor pointer ? */ 188#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 189 190/* is system segment descriptor pointer ? */ 191#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 192 193/* 194 * Segment Protection Exception code bits 195 */ 196#define SEGEX_EXT 0x01 /* recursive or externally induced */ 197#define SEGEX_IDT 0x02 /* interrupt descriptor table */ 198#define SEGEX_TI 0x04 /* local descriptor table */ 199 200/* 201 * Entries in the Interrupt Descriptor Table (IDT) 202 */ 203#define NIDT 256 204#define NRSVIDT 32 /* reserved entries for cpu exceptions */ 205 206/* 207 * Entries in the Global Descriptor Table (GDT) 208 */ 209#define GNULL_SEL 0 /* Null descriptor */ 210#define GCODE_SEL 1 /* Kernel code descriptor */ 211#define GDATA_SEL 2 /* Kernel data descriptor */ 212#define GLDT_SEL 3 /* Default LDT descriptor (UNUSED) */ 213#define GCPU_SEL 4 /* per-CPU segment */ 214#define GUCODE_SEL 5 /* User code descriptor (a stack short) */ 215#define GUDATA_SEL 6 /* User data descriptor */ 216#define GAPM32CODE_SEL 7 /* 32 bit APM code descriptor */ 217#define GAPM16CODE_SEL 8 /* 16 bit APM code descriptor */ 218#define GAPMDATA_SEL 9 /* APM data descriptor */ 219#define GICODE_SEL 10 /* Interrupt code descriptor (same as Kernel code) */ 220#define GUFS_SEL 11 /* User per-thread (%fs) descriptor */ 221#define GUGS_SEL 12 /* User per-thread (%gs) descriptor */ 222#define GTSS_SEL 13 /* common TSS */ 223#define GNMITSS_SEL 14 /* NMI TSS */ 224#define GBIOS32_SEL 15 /* spare slot for 32 bit BIOS calls */ 225#define NGDT 16 226 227#define GDT_SIZE (NGDT << 3) 228 229#endif /* _MACHINE_SEGMENTS_H_ */ 230