1 /* $NetBSD: segments.h,v 1.33 2002/01/23 15:02:34 rafal Exp $ */ 2 3 /*- 4 * Copyright (c) 1995, 1997 5 * 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 #if defined(_KERNEL_OPT) 67 #include "opt_vm86.h" 68 #endif 69 70 #ifdef VM86 71 #define USERMODE(c, f) (ISPL(c) == SEL_UPL || ((f) & PSL_VM) != 0) 72 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL && ((f) & PSL_VM) == 0) 73 #else 74 #define USERMODE(c, f) (ISPL(c) == SEL_UPL) 75 #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL) 76 #endif 77 78 #ifndef _LOCORE 79 80 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7 81 #pragma pack(1) 82 #endif 83 84 /* 85 * Memory and System segment descriptors 86 */ 87 struct segment_descriptor { 88 unsigned sd_lolimit:16; /* segment extent (lsb) */ 89 unsigned sd_lobase:24; /* segment base address (lsb) */ 90 unsigned sd_type:5; /* segment type */ 91 unsigned sd_dpl:2; /* segment descriptor priority level */ 92 unsigned sd_p:1; /* segment descriptor present */ 93 unsigned sd_hilimit:4; /* segment extent (msb) */ 94 unsigned sd_xx:2; /* unused */ 95 unsigned sd_def32:1; /* default 32 vs 16 bit size */ 96 unsigned sd_gran:1; /* limit granularity (byte/page) */ 97 unsigned sd_hibase:8; /* segment base address (msb) */ 98 } __attribute__((packed)); 99 100 /* 101 * Gate descriptors (e.g. indirect descriptors) 102 */ 103 struct gate_descriptor { 104 unsigned gd_looffset:16; /* gate offset (lsb) */ 105 unsigned gd_selector:16; /* gate segment selector */ 106 unsigned gd_stkcpy:5; /* number of stack wds to cpy */ 107 unsigned gd_xx:3; /* unused */ 108 unsigned gd_type:5; /* segment type */ 109 unsigned gd_dpl:2; /* segment descriptor priority level */ 110 unsigned gd_p:1; /* segment descriptor present */ 111 unsigned gd_hioffset:16; /* gate offset (msb) */ 112 } __attribute__((packed)); 113 114 /* 115 * Generic descriptor 116 */ 117 union descriptor { 118 struct segment_descriptor sd; 119 struct gate_descriptor gd; 120 } __attribute__((packed)); 121 122 /* 123 * region descriptors, used to load gdt/idt tables before segments yet exist. 124 */ 125 struct region_descriptor { 126 unsigned rd_limit:16; /* segment extent */ 127 unsigned rd_base:32; /* base address */ 128 } __attribute__((packed)); 129 130 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7 131 #pragma pack(4) 132 #endif 133 134 #ifdef _KERNEL 135 extern union descriptor *idt, *gdt, *ldt; 136 137 void setgate __P((struct gate_descriptor *, void *, int, int, int)); 138 void setregion __P((struct region_descriptor *, void *, size_t)); 139 void setsegment __P((struct segment_descriptor *, void *, size_t, int, int, 140 int, int)); 141 #endif /* _KERNEL */ 142 143 #endif /* !_LOCORE */ 144 145 /* system segments and gate types */ 146 #define SDT_SYSNULL 0 /* system null */ 147 #define SDT_SYS286TSS 1 /* system 286 TSS available */ 148 #define SDT_SYSLDT 2 /* system local descriptor table */ 149 #define SDT_SYS286BSY 3 /* system 286 TSS busy */ 150 #define SDT_SYS286CGT 4 /* system 286 call gate */ 151 #define SDT_SYSTASKGT 5 /* system task gate */ 152 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */ 153 #define SDT_SYS286TGT 7 /* system 286 trap gate */ 154 #define SDT_SYSNULL2 8 /* system null again */ 155 #define SDT_SYS386TSS 9 /* system 386 TSS available */ 156 #define SDT_SYSNULL3 10 /* system null again */ 157 #define SDT_SYS386BSY 11 /* system 386 TSS busy */ 158 #define SDT_SYS386CGT 12 /* system 386 call gate */ 159 #define SDT_SYSNULL4 13 /* system null again */ 160 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */ 161 #define SDT_SYS386TGT 15 /* system 386 trap gate */ 162 163 /* memory segment types */ 164 #define SDT_MEMRO 16 /* memory read only */ 165 #define SDT_MEMROA 17 /* memory read only accessed */ 166 #define SDT_MEMRW 18 /* memory read write */ 167 #define SDT_MEMRWA 19 /* memory read write accessed */ 168 #define SDT_MEMROD 20 /* memory read only expand dwn limit */ 169 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ 170 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */ 171 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ 172 #define SDT_MEME 24 /* memory execute only */ 173 #define SDT_MEMEA 25 /* memory execute only accessed */ 174 #define SDT_MEMER 26 /* memory execute read */ 175 #define SDT_MEMERA 27 /* memory execute read accessed */ 176 #define SDT_MEMEC 28 /* memory execute only conforming */ 177 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */ 178 #define SDT_MEMERC 30 /* memory execute read conforming */ 179 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */ 180 181 /* is memory segment descriptor pointer ? */ 182 #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \ 183 (s->d_type) <= SDT_MEMERAC) 184 185 /* is 286 gate descriptor pointer ? */ 186 #define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \ 187 (s->d_type) < SDT_SYS286TGT) 188 189 /* is 386 gate descriptor pointer ? */ 190 #define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \ 191 (s->d_type) < SDT_SYS386TGT) 192 193 /* is gate descriptor pointer ? */ 194 #define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) 195 196 /* is segment descriptor pointer ? */ 197 #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) 198 199 /* is system segment descriptor pointer ? */ 200 #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) 201 202 /* 203 * Segment Protection Exception code bits 204 */ 205 #define SEGEX_EXT 0x01 /* recursive or externally induced */ 206 #define SEGEX_IDT 0x02 /* interrupt descriptor table */ 207 #define SEGEX_TI 0x04 /* local descriptor table */ 208 209 /* 210 * Entries in the Interrupt Descriptor Table (IDT) 211 */ 212 #define NIDT 256 213 #define NRSVIDT 32 /* reserved entries for cpu exceptions */ 214 215 /* 216 * Entries in the Global Descriptor Table (GDT). 217 * 218 * NB: If you change GBIOSCODE/GBIOSDATA, you *must* rebuild arch/i386/ 219 * bioscall/biostramp.inc, as that relies on GBIOSCODE/GBIOSDATA and a 220 * normal kernel build does not rebuild it (it's merely included whole- 221 * sale from i386/bioscall.s) 222 * 223 * Also, note that the GEXTBIOSDATA_SEL selector is special, as it maps 224 * to the value 0x0040 (when created as a KPL global selector). Some 225 * BIOSes reference the extended BIOS data area at segment 0040 in a non 226 * relocatable fashion (even when in protected mode); mapping the zero page 227 * via the GEXTBIOSDATA_SEL allows these buggy BIOSes to continue to work 228 * under NetBSD. 229 */ 230 #define GNULL_SEL 0 /* Null descriptor */ 231 #define GCODE_SEL 1 /* Kernel code descriptor */ 232 #define GDATA_SEL 2 /* Kernel data descriptor */ 233 #define GLDT_SEL 3 /* Default LDT descriptor */ 234 #define GUCODE_SEL 4 /* User code descriptor */ 235 #define GUDATA_SEL 5 /* User data descriptor */ 236 /* reserved for GCPU_SEL 6 per-CPU segment */ 237 #define GMACHCALLS_SEL 7 /* Darwin (mach trap) system call gate */ 238 #define GEXTBIOSDATA_SEL 8 /* magic to catch BIOS refs to EBDA */ 239 #define GAPM32CODE_SEL 9 /* 3 APM segments must be consecutive */ 240 #define GAPM16CODE_SEL 10 /* and in the specified order: code32 */ 241 #define GAPMDATA_SEL 11 /* code16 and then data per APM spec */ 242 #define GBIOSCODE_SEL 12 243 #define GBIOSDATA_SEL 13 244 #define GPNPBIOSCODE_SEL 14 245 #define GPNPBIOSDATA_SEL 15 246 #define GPNPBIOSSCRATCH_SEL 16 247 #define GPNPBIOSTRAMP_SEL 17 248 #define NGDT 18 249 250 /* 251 * Entries in the Local Descriptor Table (LDT) 252 */ 253 #define LSYS5CALLS_SEL 0 /* iBCS system call gate */ 254 #define LSYS5SIGR_SEL 1 /* iBCS sigreturn gate */ 255 #define LUCODE_SEL 2 /* User code descriptor */ 256 #define LUDATA_SEL 3 /* User data descriptor */ 257 #define LSOL26CALLS_SEL 4 /* Solaris 2.6 system call gate */ 258 #define LBSDICALLS_SEL 16 /* BSDI system call gate */ 259 #define NLDT 17 260 261 #endif /* _I386_SEGMENTS_H_ */ 262