1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1990 William F. Jolitz 5 * Copyright (c) 1990 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * William Jolitz. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * from: @(#)segments.h 7.1 (Berkeley) 5/9/91 36 */ 37 38 #ifndef _MACHINE_SEGMENTS_H_ 39 #define _MACHINE_SEGMENTS_H_ 40 41 /* 42 * 386 Segmentation Data Structures and definitions 43 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 44 */ 45 46 #include <x86/segments.h> 47 48 /* 49 * Software definitions are in this convenient format, 50 * which are translated into inconvenient segment descriptors 51 * when needed to be used by the 386 hardware 52 */ 53 54 struct soft_segment_descriptor { 55 unsigned ssd_base ; /* segment base address */ 56 unsigned ssd_limit ; /* segment extent */ 57 unsigned ssd_type:5 ; /* segment type */ 58 unsigned ssd_dpl:2 ; /* segment descriptor priority level */ 59 unsigned ssd_p:1 ; /* segment descriptor present */ 60 unsigned ssd_xx:4 ; /* unused */ 61 unsigned ssd_xx1:2 ; /* unused */ 62 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */ 63 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/ 64 }; 65 66 /* 67 * region descriptors, used to load gdt/idt tables before segments yet exist. 68 */ 69 struct region_descriptor { 70 unsigned rd_limit:16; /* segment extent */ 71 unsigned rd_base:32 __packed; /* base address */ 72 }; 73 74 /* 75 * Segment Protection Exception code bits 76 */ 77 78 #define SEGEX_EXT 0x01 /* recursive or externally induced */ 79 #define SEGEX_IDT 0x02 /* interrupt descriptor table */ 80 #define SEGEX_TI 0x04 /* local descriptor table */ 81 /* other bits are affected descriptor index */ 82 #define SEGEX_IDX(s) (((s)>>3)&0x1fff) 83 84 #ifdef _KERNEL 85 extern int _default_ldt; 86 extern union descriptor *gdt; 87 extern union descriptor *ldt; 88 extern struct soft_segment_descriptor gdt_segs[]; 89 extern struct gate_descriptor *idt; 90 91 void lgdt(struct region_descriptor *rdp); 92 void sdtossd(struct segment_descriptor *sdp, 93 struct soft_segment_descriptor *ssdp); 94 void ssdtosd(struct soft_segment_descriptor *ssdp, 95 struct segment_descriptor *sdp); 96 #endif /* _KERNEL */ 97 98 #endif /* !_MACHINE_SEGMENTS_H_ */ 99