1/* $NetBSD: segments.h,v 1.38 2021/04/17 20:12:55 rillig 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 * Adapted for NetBSD/amd64 by fvdl@wasabisystems.com.
78 */
79
80/*
81 * 386 Segmentation Data Structures and definitions
82 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
83 */
84
85#ifndef _AMD64_SEGMENTS_H_
86#define _AMD64_SEGMENTS_H_
87
88#ifdef __x86_64__
89
90#ifdef _KERNEL_OPT
91#include "opt_xen.h"
92#endif
93
94/*
95 * Selectors
96 */
97
98#define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */
99#ifdef XENPV
100#define SEL_KPL 3 /* kernel privilege level */
101#define SEL_XPL 0 /* Xen Hypervisor privilege level */
102#else
103#define SEL_KPL 0 /* kernel privilege level */
104#endif
105#define SEL_UPL 3 /* user privilege level */
106#define SEL_RPL 3 /* requester's privilege level mask */
107#define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */
108#define SEL_LDT 4 /* local descriptor table */
109
110#ifdef XENPV
111#define IOPL_KPL 1
112#else
113#define IOPL_KPL SEL_KPL
114#endif
115
116/* Dynamically allocated TSSs and LDTs start (byte offset) */
117#define SYSSEL_START (NGDT_MEM << 3)
118#define DYNSEL_START (SYSSEL_START + (NGDT_SYS << 4))
119
120/*
121 * These define the index not from the start of the GDT, but from
122 * the part of the GDT that they're allocated from.
123 * First NGDT_MEM entries are 8-byte descriptors for CS and DS.
124 * Next NGDT_SYS entries are 16-byte descriptors defining LDTs.
125 *
126 * The rest is 16-byte descriptors for TSS and LDT.
127 */
128
129#define IDXSEL(s) (((s) >> 3) & 0x1fff)
130#define IDXDYNSEL(s) ((((s) & ~SEL_RPL) - DYNSEL_START) >> 4)
131
132#define GSEL(s,r) (((s) << 3) | r)
133#define GSYSSEL(s,r) ((((s) << 4) + SYSSEL_START) | r)
134#define GDYNSEL(s,r) ((((s) << 4) + DYNSEL_START) | r | SEL_KPL)
135
136#define LSEL(s,r) ((s) | r | SEL_LDT)
137
138#define USERMODE(c) (ISPL(c) == SEL_UPL)
139#ifdef XENPV
140/*
141 * As KPL == UPL, Xen emulate interrupt in kernel context by pushing
142 * a fake CS with XPL privilege
143 */
144#define KERNELMODE(c) (ISPL(c) == SEL_XPL)
145#else
146#define KERNELMODE(c) (ISPL(c) == SEL_KPL)
147#endif
148
149#ifndef _LOCORE
150
151/*
152 * Memory and System segment descriptors
153 */
154
155/*
156 * System segment descriptor (16 bytes): used for TSS and LDT.
157 */
158struct sys_segment_descriptor {
159 uint64_t sd_lolimit:16; /* segment extent (lsb) */
160 uint64_t sd_lobase:24; /* segment base address (lsb) */
161 uint64_t sd_type:5; /* segment type */
162 uint64_t sd_dpl:2; /* segment descriptor priority level */
163 uint64_t sd_p:1; /* segment descriptor present */
164 uint64_t sd_hilimit:4; /* segment extent (msb) */
165 uint64_t sd_xx1:3; /* avl, long and def32 (not used) */
166 uint64_t sd_gran:1; /* limit granularity (byte/page) */
167 uint64_t sd_hibase:40; /* segment base address (msb) */
168 uint64_t sd_xx2:8; /* reserved */
169 uint64_t sd_zero:5; /* must be zero */
170 uint64_t sd_xx3:19; /* reserved */
171} __packed;
172
173/*
174 * Memory segment descriptor (8 bytes): used for cs, ds, etc.
175 */
176struct mem_segment_descriptor {
177 unsigned sd_lolimit:16; /* segment extent (lsb) */
178 unsigned sd_lobase:24; /* segment base address (lsb) */
179 unsigned sd_type:5; /* segment type */
180 unsigned sd_dpl:2; /* segment descriptor priority level */
181 unsigned sd_p:1; /* segment descriptor present */
182 unsigned sd_hilimit:4; /* segment extent (msb) */
183 unsigned sd_avl:1; /* available */
184 unsigned sd_long:1; /* long mode */
185 unsigned sd_def32:1; /* default 32 vs 16 bit size */
186 unsigned sd_gran:1; /* limit granularity (byte/page) */
187 unsigned sd_hibase:8; /* segment base address (msb) */
188} __packed;
189
190/*
191 * Common part of the above structures. Used to walk descriptor tables.
192 */
193struct common_segment_descriptor {
194 unsigned sdc_lolimit:16;
195 unsigned sdc_lobase:24;
196 unsigned sdc_type:5;
197 unsigned sdc_other:19;
198} __packed;
199
200/*
201 * Gate descriptors (16 bytes).
202 */
203struct gate_descriptor {
204 uint64_t gd_looffset:16;/* gate offset (lsb) */
205 uint64_t gd_selector:16;/* gate segment selector */
206 uint64_t gd_ist:3; /* IST select */
207 uint64_t gd_xx1:5; /* reserved */
208 uint64_t gd_type:5; /* segment type */
209 uint64_t gd_dpl:2; /* segment descriptor priority level */
210 uint64_t gd_p:1; /* segment descriptor present */
211 uint64_t gd_hioffset:48;/* gate offset (msb) */
212 uint64_t gd_xx2:8; /* reserved */
213 uint64_t gd_zero:5; /* must be zero */
214 uint64_t gd_xx3:19; /* reserved */
215} __packed;
216
217/*
218 * Generic descriptor (8 bytes). Note: it does not include system segment
219 * descriptors and gate descriptors, since these are 16-byte-long.
220 */
221union descriptor {
222 struct mem_segment_descriptor sd;
223 uint32_t raw[2];
224 uint64_t raw64;
225} __packed;
226
227/*
228 * Region descriptors, used to load gdt/idt tables before segments yet exist.
229 */
230struct region_descriptor {
231 uint16_t rd_limit; /* segment extent */
232 uint64_t rd_base; /* base address */
233} __packed;
234
235#ifdef _KERNEL
236#ifdef XENPV
237typedef struct trap_info idt_descriptor_t;
238#else
239typedef struct gate_descriptor idt_descriptor_t;
240#endif /* XENPV */
241extern char *gdtstore;
242extern char *ldtstore;
243
244void setgate(struct gate_descriptor *, void *, int, int, int, int);
245void unsetgate(struct gate_descriptor *);
246void set_idtgate(idt_descriptor_t *, void *, int, int, int, int);
247void unset_idtgate(idt_descriptor_t *);
248void setregion(struct region_descriptor *, void *, uint16_t);
249void set_sys_segment(struct sys_segment_descriptor *, void *, size_t,
250 int, int, int);
251void set_mem_segment(struct mem_segment_descriptor *, void *, size_t,
252 int, int, int, int, int);
253void update_descriptor(void *, void *);
254
255struct idt_vec;
256void idt_vec_reserve(struct idt_vec *, int);
257int idt_vec_alloc(struct idt_vec *, int, int);
258void idt_vec_set(struct idt_vec *, int, void (*)(void));
259void idt_vec_free(struct idt_vec *, int);
260void idt_vec_init_cpu_md(struct idt_vec *, cpuid_t);
261bool idt_vec_is_pcpu(void);
262struct idt_vec * idt_vec_ref(struct idt_vec *);
263
264
265struct lwp;
266void cpu_segregs64_zero(struct lwp *);
267void cpu_segregs32_zero(struct lwp *);
268void cpu_fsgs_reload(struct lwp *, int, int);
269
270#endif /* _KERNEL */
271
272#endif /* !_LOCORE */
273
274/* system segments and gate types */
275#define SDT_SYSNULL 0 /* system null */
276#define SDT_SYS286TSS 1 /* system 286 TSS available */
277#define SDT_SYSLDT 2 /* system local descriptor table */
278#define SDT_SYS286BSY 3 /* system 286 TSS busy */
279#define SDT_SYS286CGT 4 /* system 286 call gate */
280#define SDT_SYSTASKGT 5 /* system task gate */
281#define SDT_SYS286IGT 6 /* system 286 interrupt gate */
282#define SDT_SYS286TGT 7 /* system 286 trap gate */
283#define SDT_SYSNULL2 8 /* system null again */
284#define SDT_SYS386TSS 9 /* system 386 TSS available */
285#define SDT_SYSNULL3 10 /* system null again */
286#define SDT_SYS386BSY 11 /* system 386 TSS busy */
287#define SDT_SYS386CGT 12 /* system 386 call gate */
288#define SDT_SYSNULL4 13 /* system null again */
289#define SDT_SYS386IGT 14 /* system 386 interrupt gate */
290#define SDT_SYS386TGT 15 /* system 386 trap gate */
291
292/* memory segment types */
293#define SDT_MEMRO 16 /* memory read only */
294#define SDT_MEMROA 17 /* memory read only accessed */
295#define SDT_MEMRW 18 /* memory read write */
296#define SDT_MEMRWA 19 /* memory read write accessed */
297#define SDT_MEMROD 20 /* memory read only expand dwn limit */
298#define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
299#define SDT_MEMRWD 22 /* memory read write expand dwn limit */
300#define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
301#define SDT_MEME 24 /* memory execute only */
302#define SDT_MEMEA 25 /* memory execute only accessed */
303#define SDT_MEMER 26 /* memory execute read */
304#define SDT_MEMERA 27 /* memory execute read accessed */
305#define SDT_MEMEC 28 /* memory execute only conforming */
306#define SDT_MEMEAC 29 /* memory execute only accessed conforming */
307#define SDT_MEMERC 30 /* memory execute read conforming */
308#define SDT_MEMERAC 31 /* memory execute read accessed conforming */
309
310/*
311 * Segment Protection Exception code bits
312 */
313#define SEGEX_EXT 0x01 /* recursive or externally induced */
314#define SEGEX_IDT 0x02 /* interrupt descriptor table */
315#define SEGEX_TI 0x04 /* local descriptor table */
316
317/*
318 * Entries in the Interrupt Descriptor Table (IDT)
319 */
320#define NIDT 256
321#define NCPUIDT 32 /* reserved entries for CPU exceptions */
322
323/*
324 * Entries in the Global Descriptor Table (GDT)
325 * The code and data descriptors must come first. There
326 * are NGDT_MEM of them.
327 *
328 * Then come the predefined LDT (and possibly TSS) descriptors.
329 * There are NGDT_SYS of them.
330 */
331#define GNULL_SEL 0 /* Null descriptor */
332#define GCODE_SEL 1 /* Kernel code descriptor */
333#define GDATA_SEL 2 /* Kernel data descriptor */
334#define GUCODE_SEL 3 /* User code descriptor */
335#define GUDATA_SEL 4 /* User data descriptor */
336#define GAPM32CODE_SEL 5
337#define GAPM16CODE_SEL 6
338#define GAPMDATA_SEL 7
339#define GBIOSCODE_SEL 8
340#define GBIOSDATA_SEL 9
341#define GPNPBIOSCODE_SEL 10
342#define GPNPBIOSDATA_SEL 11
343#define GPNPBIOSSCRATCH_SEL 12
344#define GPNPBIOSTRAMP_SEL 13
345#define GUCODE32_SEL 14
346#define GUDATA32_SEL 15
347#define GUFS_SEL 16 /* 32-bit Per-thread %fs */
348#define GUGS_SEL 17 /* 32-bit Per-thread %gs */
349#define NGDT_MEM 18
350
351#define GLDT_SEL 0 /* Default LDT descriptor */
352#define NGDT_SYS 1
353
354#define GDT_ADDR_MEM(s,i) \
355 ((struct mem_segment_descriptor *)((s) + ((i) << 3)))
356#define GDT_ADDR_SYS(s,i) \
357 ((struct sys_segment_descriptor *)((s) + (((i) << 4) + SYSSEL_START)))
358
359/*
360 * Byte offsets in the Local Descriptor Table (LDT)
361 * Strange order because of syscall/sysret insns
362 */
363#define LUCODE32_SEL 48 /* 32 bit user code descriptor */
364#define LUDATA_SEL 56 /* User data descriptor */
365#define LUCODE_SEL 64 /* User code descriptor */
366#define LUDATA32_SEL 72 /* 32 bit user data descriptor (needed?)*/
367
368#define LDT_SIZE 80
369
370#define LSYSRETBASE_SEL LUCODE32_SEL
371
372/*
373 * Checks for valid user selectors.
374 */
375#define VALID_USER_DSEL32(s) \
376 (((s) & 0xffff) == GSEL(GUDATA32_SEL, SEL_UPL) || \
377 ((s) & 0xffff) == LSEL(LUDATA32_SEL, SEL_UPL))
378#define VALID_USER_CSEL32(s) \
379 ((s) == GSEL(GUCODE32_SEL, SEL_UPL) || (s) == LSEL(LUCODE32_SEL, SEL_UPL))
380#define VALID_USER_FSEL32(s) \
381 (((s) & 0xffff) == GSEL(GUFS_SEL, SEL_UPL))
382#define VALID_USER_GSEL32(s) \
383 (((s) & 0xffff) == GSEL(GUGS_SEL, SEL_UPL))
384
385#define VALID_USER_CSEL(s) \
386 ((s) == GSEL(GUCODE_SEL, SEL_UPL) || (s) == LSEL(LUCODE_SEL, SEL_UPL))
387#define VALID_USER_DSEL(s) \
388 ((s) == GSEL(GUDATA_SEL, SEL_UPL) || (s) == LSEL(LUDATA_SEL, SEL_UPL))
389
390#else /* __x86_64__ */
391
392#include <i386/segments.h>
393
394#endif /* __x86_64__ */
395
396#endif /* _AMD64_SEGMENTS_H_ */