xref: /netbsd-src/sys/arch/amd64/include/segments.h (revision 63587e37ee62a993fb53e201ae81ff76361b4eb6)
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  */
158 struct 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  */
176 struct 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  */
193 struct 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  */
203 struct 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  */
221 union 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  */
230 struct 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
237 typedef struct trap_info idt_descriptor_t;
238 #else
239 typedef struct gate_descriptor idt_descriptor_t;
240 #endif /* XENPV */
241 extern char *gdtstore;
242 extern char *ldtstore;
243 
244 void setgate(struct gate_descriptor *, void *, int, int, int, int);
245 void unsetgate(struct gate_descriptor *);
246 void set_idtgate(idt_descriptor_t *, void *, int, int, int, int);
247 void unset_idtgate(idt_descriptor_t *);
248 void setregion(struct region_descriptor *, void *, uint16_t);
249 void set_sys_segment(struct sys_segment_descriptor *, void *, size_t,
250     int, int, int);
251 void set_mem_segment(struct mem_segment_descriptor *, void *, size_t,
252     int, int, int, int, int);
253 void update_descriptor(void *, void *);
254 
255 struct idt_vec;
256 void idt_vec_reserve(struct idt_vec *, int);
257 int idt_vec_alloc(struct idt_vec *, int, int);
258 void idt_vec_set(struct idt_vec *, int, void (*)(void));
259 void idt_vec_free(struct idt_vec *, int);
260 void idt_vec_init_cpu_md(struct idt_vec *, cpuid_t);
261 bool idt_vec_is_pcpu(void);
262 struct idt_vec * idt_vec_ref(struct idt_vec *);
263 
264 
265 struct lwp;
266 void cpu_segregs64_zero(struct lwp *);
267 void cpu_segregs32_zero(struct lwp *);
268 void 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_ */
397