xref: /freebsd/sys/x86/include/segments.h (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
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 _X86_SEGMENTS_H_
39 #define	_X86_SEGMENTS_H_
40 
41 /*
42  * X86 Segmentation Data Structures and definitions
43  */
44 
45 /*
46  * Selectors
47  */
48 #define	SEL_RPL_MASK	3		/* requester priv level */
49 #define	ISPL(s)		((s)&3)		/* priority level of a selector */
50 #define	SEL_KPL		0		/* kernel priority level */
51 #define	SEL_UPL		3		/* user priority level */
52 #define	ISLDT(s)	((s)&SEL_LDT)	/* is it local or global */
53 #define	SEL_LDT		4		/* local descriptor table */
54 #define	IDXSEL(s)	(((s)>>3) & 0x1fff) /* index of selector */
55 #define	LSEL(s,r)	(((s)<<3) | SEL_LDT | r) /* a local selector */
56 #define	GSEL(s,r)	(((s)<<3) | r)	/* a global selector */
57 
58 /*
59  * User segment descriptors (%cs, %ds etc for i386 apps. 64 bit wide)
60  * For long-mode apps, %cs only has the conforming bit in sd_type, the sd_dpl,
61  * sd_p, sd_l and sd_def32 which must be zero).  %ds only has sd_p.
62  */
63 struct segment_descriptor {
64 	unsigned sd_lolimit:16;		/* segment extent (lsb) */
65 	unsigned sd_lobase:24;		/* segment base address (lsb) */
66 	unsigned sd_type:5;		/* segment type */
67 	unsigned sd_dpl:2;		/* segment descriptor priority level */
68 	unsigned sd_p:1;		/* segment descriptor present */
69 	unsigned sd_hilimit:4;		/* segment extent (msb) */
70 	unsigned sd_xx:2;		/* unused */
71 	unsigned sd_def32:1;		/* default 32 vs 16 bit size */
72 	unsigned sd_gran:1;		/* limit granularity (byte/page units)*/
73 	unsigned sd_hibase:8;		/* segment base address  (msb) */
74 } __packed;
75 
76 struct user_segment_descriptor {
77 	unsigned sd_lolimit:16;		/* segment extent (lsb) */
78 	unsigned sd_lobase:24;		/* segment base address (lsb) */
79 	unsigned sd_type:5;		/* segment type */
80 	unsigned sd_dpl:2;		/* segment descriptor priority level */
81 	unsigned sd_p:1;		/* segment descriptor present */
82 	unsigned sd_hilimit:4;		/* segment extent (msb) */
83 	unsigned sd_xx:1;		/* unused */
84 	unsigned sd_long:1;		/* long mode (cs only) */
85 	unsigned sd_def32:1;		/* default 32 vs 16 bit size */
86 	unsigned sd_gran:1;		/* limit granularity (byte/page units)*/
87 	unsigned sd_hibase:8;		/* segment base address  (msb) */
88 } __packed;
89 
90 #define	USD_GETBASE(sd)		(((sd)->sd_lobase) | (sd)->sd_hibase << 24)
91 #define	USD_SETBASE(sd, b)	(sd)->sd_lobase = (b);	\
92 				(sd)->sd_hibase = ((b) >> 24);
93 #define	USD_GETLIMIT(sd)	(((sd)->sd_lolimit) | (sd)->sd_hilimit << 16)
94 #define	USD_SETLIMIT(sd, l)	(sd)->sd_lolimit = (l);	\
95 				(sd)->sd_hilimit = ((l) >> 16);
96 
97 #ifdef __i386__
98 /*
99  * Gate descriptors (e.g. indirect descriptors)
100  */
101 struct gate_descriptor {
102 	unsigned gd_looffset:16;	/* gate offset (lsb) */
103 	unsigned gd_selector:16;	/* gate segment selector */
104 	unsigned gd_stkcpy:5;		/* number of stack wds to cpy */
105 	unsigned gd_xx:3;		/* unused */
106 	unsigned gd_type:5;		/* segment type */
107 	unsigned gd_dpl:2;		/* segment descriptor priority level */
108 	unsigned gd_p:1;		/* segment descriptor present */
109 	unsigned gd_hioffset:16;	/* gate offset (msb) */
110 } __packed;
111 
112 /*
113  * Generic descriptor
114  */
115 union descriptor {
116 	struct segment_descriptor sd;
117 	struct gate_descriptor gd;
118 };
119 #else
120 /*
121  * Gate descriptors (e.g. indirect descriptors, trap, interrupt etc. 128 bit)
122  * Only interrupt and trap gates have gd_ist.
123  */
124 struct gate_descriptor {
125 	uint64_t gd_looffset:16;	/* gate offset (lsb) */
126 	uint64_t gd_selector:16;	/* gate segment selector */
127 	uint64_t gd_ist:3;		/* IST table index */
128 	uint64_t gd_xx:5;		/* unused */
129 	uint64_t gd_type:5;		/* segment type */
130 	uint64_t gd_dpl:2;		/* segment descriptor priority level */
131 	uint64_t gd_p:1;		/* segment descriptor present */
132 	uint64_t gd_hioffset:48;	/* gate offset (msb) */
133 	uint64_t sd_xx1:32;
134 } __packed;
135 
136 /*
137  * Generic descriptor
138  */
139 union descriptor {
140 	struct user_segment_descriptor sd;
141 	struct gate_descriptor gd;
142 };
143 #endif
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_SYSTSS	 9	/* system available 64 bit TSS */
157 #define	SDT_SYSNULL3	10	/* system null again */
158 #define	SDT_SYS386BSY	11	/* system 386 TSS busy */
159 #define	SDT_SYSBSY	11	/* system busy 64 bit TSS */
160 #define	SDT_SYS386CGT	12	/* system 386 call gate */
161 #define	SDT_SYSCGT	12	/* system 64 bit call gate */
162 #define	SDT_SYSNULL4	13	/* system null again */
163 #define	SDT_SYS386IGT	14	/* system 386 interrupt gate */
164 #define	SDT_SYSIGT	14	/* system 64 bit interrupt gate */
165 #define	SDT_SYS386TGT	15	/* system 386 trap gate */
166 #define	SDT_SYSTGT	15	/* system 64 bit trap gate */
167 
168 	/* memory segment types */
169 #define	SDT_MEMRO	16	/* memory read only */
170 #define	SDT_MEMROA	17	/* memory read only accessed */
171 #define	SDT_MEMRW	18	/* memory read write */
172 #define	SDT_MEMRWA	19	/* memory read write accessed */
173 #define	SDT_MEMROD	20	/* memory read only expand dwn limit */
174 #define	SDT_MEMRODA	21	/* memory read only expand dwn limit accessed */
175 #define	SDT_MEMRWD	22	/* memory read write expand dwn limit */
176 #define	SDT_MEMRWDA	23	/* memory read write expand dwn limit accessed*/
177 #define	SDT_MEME	24	/* memory execute only */
178 #define	SDT_MEMEA	25	/* memory execute only accessed */
179 #define	SDT_MEMER	26	/* memory execute read */
180 #define	SDT_MEMERA	27	/* memory execute read accessed */
181 #define	SDT_MEMEC	28	/* memory execute only conforming */
182 #define	SDT_MEMEAC	29	/* memory execute only accessed conforming */
183 #define	SDT_MEMERC	30	/* memory execute read conforming */
184 #define	SDT_MEMERAC	31	/* memory execute read accessed conforming */
185 
186 /*
187  * Size of IDT table
188  */
189 #define	NIDT		256	/* 32 reserved, 0x80 syscall, most are h/w */
190 #define	NRSVIDT		32	/* reserved entries for cpu exceptions */
191 
192 /*
193  * Entries in the Interrupt Descriptor Table (IDT)
194  */
195 #define	IDT_DE		0	/* #DE: Divide Error */
196 #define	IDT_DB		1	/* #DB: Debug */
197 #define	IDT_NMI		2	/* Nonmaskable External Interrupt */
198 #define	IDT_BP		3	/* #BP: Breakpoint */
199 #define	IDT_OF		4	/* #OF: Overflow */
200 #define	IDT_BR		5	/* #BR: Bound Range Exceeded */
201 #define	IDT_UD		6	/* #UD: Undefined/Invalid Opcode */
202 #define	IDT_NM		7	/* #NM: No Math Coprocessor */
203 #define	IDT_DF		8	/* #DF: Double Fault */
204 #define	IDT_FPUGP	9	/* Coprocessor Segment Overrun */
205 #define	IDT_TS		10	/* #TS: Invalid TSS */
206 #define	IDT_NP		11	/* #NP: Segment Not Present */
207 #define	IDT_SS		12	/* #SS: Stack Segment Fault */
208 #define	IDT_GP		13	/* #GP: General Protection Fault */
209 #define	IDT_PF		14	/* #PF: Page Fault */
210 #define	IDT_MF		16	/* #MF: FPU Floating-Point Error */
211 #define	IDT_AC		17	/* #AC: Alignment Check */
212 #define	IDT_MC		18	/* #MC: Machine Check */
213 #define	IDT_XF		19	/* #XF: SIMD Floating-Point Exception */
214 #define	IDT_IO_INTS	NRSVIDT	/* Base of IDT entries for I/O interrupts. */
215 #define	IDT_SYSCALL	0x80	/* System Call Interrupt Vector */
216 #define	IDT_DTRACE_RET	0x92	/* DTrace pid provider Interrupt Vector */
217 #define	IDT_EVTCHN	0x93	/* Xen HVM Event Channel Interrupt Vector */
218 
219 #if defined(__i386__)
220 /*
221  * Entries in the Global Descriptor Table (GDT)
222  * Note that each 4 entries share a single 32 byte L1 cache line.
223  * Some of the fast syscall instructions require a specific order here.
224  */
225 #define	GNULL_SEL	0	/* Null Descriptor */
226 #define	GPRIV_SEL	1	/* SMP Per-Processor Private Data */
227 #define	GUFS_SEL	2	/* User %fs Descriptor (order critical: 1) */
228 #define	GUGS_SEL	3	/* User %gs Descriptor (order critical: 2) */
229 #define	GCODE_SEL	4	/* Kernel Code Descriptor (order critical: 1) */
230 #define	GDATA_SEL	5	/* Kernel Data Descriptor (order critical: 2) */
231 #define	GUCODE_SEL	6	/* User Code Descriptor (order critical: 3) */
232 #define	GUDATA_SEL	7	/* User Data Descriptor (order critical: 4) */
233 #define	GBIOSLOWMEM_SEL	8	/* BIOS low memory access (must be entry 8) */
234 #define	GPROC0_SEL	9	/* Task state process slot zero and up */
235 #define	GLDT_SEL	10	/* Default User LDT */
236 #define	GUSERLDT_SEL	11	/* User LDT */
237 #define	GPANIC_SEL	12	/* Task state to consider panic from */
238 #define	GBIOSCODE32_SEL	13	/* BIOS interface (32bit Code) */
239 #define	GBIOSCODE16_SEL	14	/* BIOS interface (16bit Code) */
240 #define	GBIOSDATA_SEL	15	/* BIOS interface (Data) */
241 #define	GBIOSUTIL_SEL	16	/* BIOS interface (Utility) */
242 #define	GBIOSARGS_SEL	17	/* BIOS interface (Arguments) */
243 #define	GNDIS_SEL	18	/* For the NDIS layer */
244 #define	NGDT		19
245 
246 /*
247  * Entries in the Local Descriptor Table (LDT)
248  */
249 #define	LSYS5CALLS_SEL	0	/* forced by intel BCS */
250 #define	LSYS5SIGR_SEL	1
251 #define	LUCODE_SEL	3
252 #define	LUDATA_SEL	5
253 #define	NLDT		(LUDATA_SEL + 1)
254 
255 #else /* !__i386__ */
256 /*
257  * Entries in the Global Descriptor Table (GDT)
258  */
259 #define	GNULL_SEL	0	/* Null Descriptor */
260 #define	GNULL2_SEL	1	/* Null Descriptor */
261 #define	GUFS32_SEL	2	/* User 32 bit %fs Descriptor */
262 #define	GUGS32_SEL	3	/* User 32 bit %gs Descriptor */
263 #define	GCODE_SEL	4	/* Kernel Code Descriptor */
264 #define	GDATA_SEL	5	/* Kernel Data Descriptor */
265 #define	GUCODE32_SEL	6	/* User 32 bit code Descriptor */
266 #define	GUDATA_SEL	7	/* User 32/64 bit Data Descriptor */
267 #define	GUCODE_SEL	8	/* User 64 bit Code Descriptor */
268 #define	GPROC0_SEL	9	/* TSS for entering kernel etc */
269 /* slot 10 is second half of GPROC0_SEL */
270 #define	GUSERLDT_SEL	11	/* LDT */
271 /* slot 12 is second half of GUSERLDT_SEL */
272 #define	NGDT 		13
273 #endif /* __i386__ */
274 
275 #endif /* !_X86_SEGMENTS_H_ */
276