1/* $NetBSD: segments.h,v 1.70 2022/05/18 13:56:32 andvar Exp $ */
2
3/*-
4 * Copyright (c) 1990 The Regents of the University of California.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * William Jolitz.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)segments.h 7.1 (Berkeley) 5/9/91
35 */
36
37/*-
38 * Copyright (c) 1995, 1997
39 * Charles M. Hannum. All rights reserved.
40 * Copyright (c) 1989, 1990 William F. Jolitz
41 *
42 * This code is derived from software contributed to Berkeley by
43 * William Jolitz.
44 *
45 * Redistribution and use in source and binary forms, with or without
46 * modification, are permitted provided that the following conditions
47 * are met:
48 * 1. Redistributions of source code must retain the above copyright
49 * notice, this list of conditions and the following disclaimer.
50 * 2. Redistributions in binary form must reproduce the above copyright
51 * notice, this list of conditions and the following disclaimer in the
52 * documentation and/or other materials provided with the distribution.
53 * 3. All advertising materials mentioning features or use of this software
54 * must display the following acknowledgement:
55 * This product includes software developed by the University of
56 * California, Berkeley and its contributors.
57 * 4. Neither the name of the University nor the names of its contributors
58 * may be used to endorse or promote products derived from this software
59 * without specific prior written permission.
60 *
61 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
62 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
63 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
64 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
65 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
66 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
67 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
68 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
69 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
70 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
71 * SUCH DAMAGE.
72 *
73 * @(#)segments.h 7.1 (Berkeley) 5/9/91
74 */
75
76/*
77 * 386 Segmentation Data Structures and definitions
78 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
79 */
80
81#ifndef _I386_SEGMENTS_H_
82#define _I386_SEGMENTS_H_
83#ifdef _KERNEL_OPT
84#include "opt_xen.h"
85#endif
86
87/*
88 * Selectors
89 */
90
91#define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */
92#ifndef XENPV
93#define SEL_KPL 0 /* kernel privilege level */
94#else
95#define SEL_XEN 0 /* Xen privilege level */
96#define SEL_KPL 1 /* kernel privilege level */
97#endif /* XENPV */
98#define SEL_UPL 3 /* user privilege level */
99#define SEL_RPL 3 /* requester's privilege level mask */
100#ifdef XENPV
101#define CHK_UPL 2 /* user privilege level mask */
102#else
103#define CHK_UPL SEL_RPL
104#endif /* XENPV */
105#define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */
106#define SEL_LDT 4 /* local descriptor table */
107
108#define IOPL_KPL SEL_KPL
109
110/* Dynamically allocated TSSs and LDTs start (byte offset) */
111#define DYNSEL_START (NGDT << 3)
112
113#define IDXSEL(s) (((s) >> 3) & 0x1fff) /* index of selector */
114#define IDXSELN(s) (((s) >> 3)) /* index of selector */
115#define IDXDYNSEL(s) ((((s) & ~SEL_RPL) - DYNSEL_START) >> 3)
116
117#define GSEL(s,r) (((s) << 3) | r) /* a global selector */
118#define GSYSSEL(s,r) GSEL(s,r) /* compat with amd64 */
119#define GDYNSEL(s,r) ((((s) << 3) + DYNSEL_START) | r | SEL_KPL)
120
121#define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */
122
123#define USERMODE(c) (ISPL(c) == SEL_UPL)
124#define KERNELMODE(c) (ISPL(c) == SEL_KPL)
125
126#ifndef _LOCORE
127
128#if __GNUC__ == 2 && __GNUC_MINOR__ < 7
129#pragma pack(1)
130#endif
131
132/*
133 * Memory and System segment descriptors (both 8 bytes).
134 */
135struct segment_descriptor {
136 unsigned sd_lolimit:16; /* segment extent (lsb) */
137 unsigned sd_lobase:24; /* segment base address (lsb) */
138 unsigned sd_type:5; /* segment type */
139 unsigned sd_dpl:2; /* segment descriptor priority level */
140 unsigned sd_p:1; /* segment descriptor present */
141 unsigned sd_hilimit:4; /* segment extent (msb) */
142 unsigned sd_xx:2; /* unused */
143 unsigned sd_def32:1; /* default 32 vs 16 bit size */
144 unsigned sd_gran:1; /* limit granularity (byte/page) */
145 unsigned sd_hibase:8; /* segment base address (msb) */
146} __packed;
147
148/*
149 * Gate descriptors (8 bytes).
150 */
151struct gate_descriptor {
152 unsigned gd_looffset:16; /* gate offset (lsb) */
153 unsigned gd_selector:16; /* gate segment selector */
154 unsigned gd_stkcpy:5; /* number of stack wds to cpy */
155 unsigned gd_xx:3; /* unused */
156 unsigned gd_type:5; /* segment type */
157 unsigned gd_dpl:2; /* segment descriptor priority level */
158 unsigned gd_p:1; /* segment descriptor present */
159 unsigned gd_hioffset:16; /* gate offset (msb) */
160} __packed;
161
162/*
163 * Xen-specific?
164 */
165struct ldt_descriptor {
166 __vaddr_t ld_base;
167 uint32_t ld_entries;
168} __packed;
169
170/*
171 * Generic descriptor (8 bytes).
172 */
173union descriptor {
174 struct segment_descriptor sd;
175 struct gate_descriptor gd;
176 struct ldt_descriptor ld;
177 uint32_t raw[2];
178 uint64_t raw64;
179} __packed;
180
181/*
182 * Region descriptors, used to load gdt/idt tables before segments yet exist.
183 */
184struct region_descriptor {
185 unsigned rd_limit:16; /* segment extent */
186 unsigned rd_base:32; /* base address */
187} __packed;
188
189#if __GNUC__ == 2 && __GNUC_MINOR__ < 7
190#pragma pack(4)
191#endif
192
193#ifdef _KERNEL
194#ifdef XENPV
195typedef struct trap_info idt_descriptor_t;
196#else
197typedef struct gate_descriptor idt_descriptor_t;
198#endif /* XENPV */
199extern union descriptor *gdtstore, *ldtstore;
200
201void setgate(struct gate_descriptor *, void *, int, int, int, int);
202void set_idtgate(idt_descriptor_t *, void *, int, int, int, int);
203void unset_idtgate(idt_descriptor_t *);
204void setregion(struct region_descriptor *, void *, size_t);
205void setsegment(struct segment_descriptor *, const void *, size_t, int, int,
206 int, int);
207void unsetgate(struct gate_descriptor *);
208void update_descriptor(union descriptor *, union descriptor *);
209
210struct idt_vec;
211void idt_vec_reserve(struct idt_vec *, int);
212int idt_vec_alloc(struct idt_vec *, int, int);
213void idt_vec_set(struct idt_vec *, int, void (*)(void));
214void idt_vec_free(struct idt_vec *, int);
215void idt_vec_init_cpu_md(struct idt_vec *, cpuid_t);
216bool idt_vec_is_pcpu(void);
217struct idt_vec* idt_vec_ref(struct idt_vec *);
218
219
220#endif /* _KERNEL */
221
222#endif /* !_LOCORE */
223
224/* system segments and gate types */
225#define SDT_SYSNULL 0 /* system null */
226#define SDT_SYS286TSS 1 /* system 286 TSS available */
227#define SDT_SYSLDT 2 /* system local descriptor table */
228#define SDT_SYS286BSY 3 /* system 286 TSS busy */
229#define SDT_SYS286CGT 4 /* system 286 call gate */
230#define SDT_SYSTASKGT 5 /* system task gate */
231#define SDT_SYS286IGT 6 /* system 286 interrupt gate */
232#define SDT_SYS286TGT 7 /* system 286 trap gate */
233#define SDT_SYSNULL2 8 /* system null again */
234#define SDT_SYS386TSS 9 /* system 386 TSS available */
235#define SDT_SYSNULL3 10 /* system null again */
236#define SDT_SYS386BSY 11 /* system 386 TSS busy */
237#define SDT_SYS386CGT 12 /* system 386 call gate */
238#define SDT_SYSNULL4 13 /* system null again */
239#define SDT_SYS386IGT 14 /* system 386 interrupt gate */
240#define SDT_SYS386TGT 15 /* system 386 trap gate */
241
242/* memory segment types */
243#define SDT_MEMRO 16 /* memory read only */
244#define SDT_MEMROA 17 /* memory read only accessed */
245#define SDT_MEMRW 18 /* memory read write */
246#define SDT_MEMRWA 19 /* memory read write accessed */
247#define SDT_MEMROD 20 /* memory read only expand dwn limit */
248#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
249#define SDT_MEMRWD 22 /* memory read write expand dwn limit */
250#define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
251#define SDT_MEME 24 /* memory execute only */
252#define SDT_MEMEA 25 /* memory execute only accessed */
253#define SDT_MEMER 26 /* memory execute read */
254#define SDT_MEMERA 27 /* memory execute read accessed */
255#define SDT_MEMEC 28 /* memory execute only conforming */
256#define SDT_MEMEAC 29 /* memory execute only accessed conforming */
257#define SDT_MEMERC 30 /* memory execute read conforming */
258#define SDT_MEMERAC 31 /* memory execute read accessed conforming */
259
260#define SDTYPE(p) (((const struct segment_descriptor *)(p))->sd_type)
261/* is memory segment descriptor pointer ? */
262#define ISMEMSDP(s) (SDTYPE(s) >= SDT_MEMRO && \
263 SDTYPE(s) <= SDT_MEMERAC)
264
265/* is 286 gate descriptor pointer ? */
266#define IS286GDP(s) (SDTYPE(s) >= SDT_SYS286CGT && \
267 SDTYPE(s) < SDT_SYS286TGT)
268
269/* is 386 gate descriptor pointer ? */
270#define IS386GDP(s) (SDTYPE(s) >= SDT_SYS386CGT && \
271 SDTYPE(s) < SDT_SYS386TGT)
272
273/* is gate descriptor pointer ? */
274#define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
275
276/* is segment descriptor pointer ? */
277#define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
278
279/* is system segment descriptor pointer ? */
280#define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
281
282/*
283 * Segment Protection Exception code bits
284 */
285#define SEGEX_EXT 0x01 /* recursive or externally induced */
286#define SEGEX_IDT 0x02 /* interrupt descriptor table */
287#define SEGEX_TI 0x04 /* local descriptor table */
288
289/*
290 * Entries in the Interrupt Descriptor Table (IDT)
291 */
292#define NIDT 256
293#define NRSVIDT 32 /* reserved entries for CPU exceptions */
294
295/*
296 * Entries in the Global Descriptor Table (GDT).
297 *
298 * NB: If you change GBIOSCODE/GBIOSDATA, you *must* rebuild arch/i386/
299 * bioscall/biostramp.inc, as that relies on GBIOSCODE/GBIOSDATA and a
300 * normal kernel build does not rebuild it (it's merely included whole-
301 * sale from i386/bioscall.s)
302 *
303 * Also, note that the GEXTBIOSDATA_SEL selector is special, as it maps
304 * to the value 0x0040 (when created as a KPL global selector). Some
305 * BIOSes reference the extended BIOS data area at segment 0040 in a non
306 * relocatable fashion (even when in protected mode); mapping the zero page
307 * via the GEXTBIOSDATA_SEL allows these buggy BIOSes to continue to work
308 * under NetBSD.
309 *
310 * The order if the first 5 descriptors is special; the sysenter/sysexit
311 * instructions depend on them.
312 */
313#define GNULL_SEL 0 /* Null descriptor */
314#define GCODE_SEL 1 /* Kernel code descriptor */
315#define GDATA_SEL 2 /* Kernel data descriptor */
316#define GUCODE_SEL 3 /* User code descriptor */
317#define GUDATA_SEL 4 /* User data descriptor */
318#define GLDT_SEL 5 /* Default LDT descriptor */
319#define GCPU_SEL 6 /* per-CPU segment */
320#define GEXTBIOSDATA_SEL 8 /* magic to catch BIOS refs to EBDA */
321#define GAPM32CODE_SEL 9 /* 3 APM segments must be consecutive */
322#define GAPM16CODE_SEL 10 /* and in the specified order: code32 */
323#define GAPMDATA_SEL 11 /* code16 and then data per APM spec */
324#define GBIOSCODE_SEL 12
325#define GBIOSDATA_SEL 13
326#define GPNPBIOSCODE_SEL 14
327#define GPNPBIOSDATA_SEL 15
328#define GPNPBIOSSCRATCH_SEL 16
329#define GPNPBIOSTRAMP_SEL 17
330#define GTRAPTSS_SEL 18
331#define GIPITSS_SEL 19
332#define GUCODEBIG_SEL 20 /* User code with executable stack */
333#define GUFS_SEL 21 /* Per-thread %fs */
334#define GUGS_SEL 22 /* Per-thread %gs */
335#define NGDT 23
336
337/*
338 * Entries in the Local Descriptor Table (LDT).
339 * DO NOT ADD KERNEL DATA/CODE SEGMENTS TO THIS TABLE.
340 */
341#define LSYS5CALLS_SEL 0 /* iBCS system call gate */
342#define LSYS5SIGR_SEL 1 /* iBCS sigreturn gate */
343#define LUCODE_SEL 2 /* User code descriptor */
344#define LUDATA_SEL 3 /* User data descriptor */
345#define LSOL26CALLS_SEL 4 /* Solaris 2.6 system call gate */
346#define LUCODEBIG_SEL 5 /* User code with executable stack */
347#define LBSDICALLS_SEL 16 /* BSDI system call gate */
348#define NLDT 17
349
350#endif /* _I386_SEGMENTS_H_ */