xref: /freebsd/sys/i386/include/segments.h (revision 0f2bd1e89db1a2f09268edea21e0ead329e092df)
1 /*-
2  * Copyright (c) 1989, 1990 William F. Jolitz
3  * Copyright (c) 1990 The Regents of the University of California.
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * William Jolitz.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	from: @(#)segments.h	7.1 (Berkeley) 5/9/91
34  * $FreeBSD$
35  */
36 
37 #ifndef _MACHINE_SEGMENTS_H_
38 #define	_MACHINE_SEGMENTS_H_
39 
40 /*
41  * 386 Segmentation Data Structures and definitions
42  *	William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
43  */
44 
45 /*
46  * Selectors
47  */
48 
49 #define	ISPL(s)	((s)&3)		/* what is the priority level of a selector */
50 #ifdef XEN
51 #define	SEL_KPL	1		/* kernel priority level */
52 #else
53 #define	SEL_KPL	0		/* kernel priority level */
54 #endif
55 #define	SEL_UPL	3		/* user priority level */
56 #define	ISLDT(s)	((s)&SEL_LDT)	/* is it local or global */
57 #define	SEL_LDT	4		/* local descriptor table */
58 #define	IDXSEL(s)	(((s)>>3) & 0x1fff)		/* index of selector */
59 #define	LSEL(s,r)	(((s)<<3) | SEL_LDT | r)	/* a local selector */
60 #define	GSEL(s,r)	(((s)<<3) | r)			/* a global selector */
61 
62 /*
63  * Memory and System segment descriptors
64  */
65 struct	segment_descriptor	{
66 	unsigned sd_lolimit:16 ;	/* segment extent (lsb) */
67 	unsigned sd_lobase:24 __packed;	/* segment base address (lsb) */
68 	unsigned sd_type:5 ;		/* segment type */
69 	unsigned sd_dpl:2 ;		/* segment descriptor priority level */
70 	unsigned sd_p:1 ;		/* segment descriptor present */
71 	unsigned sd_hilimit:4 ;		/* segment extent (msb) */
72 	unsigned sd_xx:2 ;		/* unused */
73 	unsigned sd_def32:1 ;		/* default 32 vs 16 bit size */
74 	unsigned sd_gran:1 ;		/* limit granularity (byte/page units)*/
75 	unsigned sd_hibase:8 ;		/* segment base address  (msb) */
76 } ;
77 
78 #define	USD_GETBASE(sd)		(((sd)->sd_lobase) | (sd)->sd_hibase << 24)
79 #define	USD_SETBASE(sd, b)	(sd)->sd_lobase = (b);  \
80 				(sd)->sd_hibase = ((b) >> 24);
81 #define	USD_GETLIMIT(sd)	(((sd)->sd_lolimit) | (sd)->sd_hilimit << 16)
82 #define	USD_SETLIMIT(sd, l)	(sd)->sd_lolimit = (l); \
83 				(sd)->sd_hilimit = ((l) >> 16);
84 
85 /*
86  * Gate descriptors (e.g. indirect descriptors)
87  */
88 struct	gate_descriptor	{
89 	unsigned gd_looffset:16 ;	/* gate offset (lsb) */
90 	unsigned gd_selector:16 ;	/* gate segment selector */
91 	unsigned gd_stkcpy:5 ;		/* number of stack wds to cpy */
92 	unsigned gd_xx:3 ;		/* unused */
93 	unsigned gd_type:5 ;		/* segment type */
94 	unsigned gd_dpl:2 ;		/* segment descriptor priority level */
95 	unsigned gd_p:1 ;		/* segment descriptor present */
96 	unsigned gd_hioffset:16 ;	/* gate offset (msb) */
97 } ;
98 
99 /*
100  * Generic descriptor
101  */
102 union	descriptor	{
103 	struct	segment_descriptor sd;
104 	struct	gate_descriptor gd;
105 };
106 
107 	/* system segments and gate types */
108 #define	SDT_SYSNULL	 0	/* system null */
109 #define	SDT_SYS286TSS	 1	/* system 286 TSS available */
110 #define	SDT_SYSLDT	 2	/* system local descriptor table */
111 #define	SDT_SYS286BSY	 3	/* system 286 TSS busy */
112 #define	SDT_SYS286CGT	 4	/* system 286 call gate */
113 #define	SDT_SYSTASKGT	 5	/* system task gate */
114 #define	SDT_SYS286IGT	 6	/* system 286 interrupt gate */
115 #define	SDT_SYS286TGT	 7	/* system 286 trap gate */
116 #define	SDT_SYSNULL2	 8	/* system null again */
117 #define	SDT_SYS386TSS	 9	/* system 386 TSS available */
118 #define	SDT_SYSNULL3	10	/* system null again */
119 #define	SDT_SYS386BSY	11	/* system 386 TSS busy */
120 #define	SDT_SYS386CGT	12	/* system 386 call gate */
121 #define	SDT_SYSNULL4	13	/* system null again */
122 #define	SDT_SYS386IGT	14	/* system 386 interrupt gate */
123 #define	SDT_SYS386TGT	15	/* system 386 trap gate */
124 
125 	/* memory segment types */
126 #define	SDT_MEMRO	16	/* memory read only */
127 #define	SDT_MEMROA	17	/* memory read only accessed */
128 #define	SDT_MEMRW	18	/* memory read write */
129 #define	SDT_MEMRWA	19	/* memory read write accessed */
130 #define	SDT_MEMROD	20	/* memory read only expand dwn limit */
131 #define	SDT_MEMRODA	21	/* memory read only expand dwn limit accessed */
132 #define	SDT_MEMRWD	22	/* memory read write expand dwn limit */
133 #define	SDT_MEMRWDA	23	/* memory read write expand dwn limit accessed */
134 #define	SDT_MEME	24	/* memory execute only */
135 #define	SDT_MEMEA	25	/* memory execute only accessed */
136 #define	SDT_MEMER	26	/* memory execute read */
137 #define	SDT_MEMERA	27	/* memory execute read accessed */
138 #define	SDT_MEMEC	28	/* memory execute only conforming */
139 #define	SDT_MEMEAC	29	/* memory execute only accessed conforming */
140 #define	SDT_MEMERC	30	/* memory execute read conforming */
141 #define	SDT_MEMERAC	31	/* memory execute read accessed conforming */
142 
143 /*
144  * Software definitions are in this convenient format,
145  * which are translated into inconvenient segment descriptors
146  * when needed to be used by the 386 hardware
147  */
148 
149 struct	soft_segment_descriptor	{
150 	unsigned ssd_base ;		/* segment base address  */
151 	unsigned ssd_limit ;		/* segment extent */
152 	unsigned ssd_type:5 ;		/* segment type */
153 	unsigned ssd_dpl:2 ;		/* segment descriptor priority level */
154 	unsigned ssd_p:1 ;		/* segment descriptor present */
155 	unsigned ssd_xx:4 ;		/* unused */
156 	unsigned ssd_xx1:2 ;		/* unused */
157 	unsigned ssd_def32:1 ;		/* default 32 vs 16 bit size */
158 	unsigned ssd_gran:1 ;		/* limit granularity (byte/page units)*/
159 };
160 
161 /*
162  * region descriptors, used to load gdt/idt tables before segments yet exist.
163  */
164 struct region_descriptor {
165 	unsigned rd_limit:16;		/* segment extent */
166 	unsigned rd_base:32 __packed;	/* base address  */
167 };
168 
169 /*
170  * Segment Protection Exception code bits
171  */
172 
173 #define	SEGEX_EXT	0x01	/* recursive or externally induced */
174 #define	SEGEX_IDT	0x02	/* interrupt descriptor table */
175 #define	SEGEX_TI	0x04	/* local descriptor table */
176 				/* other bits are affected descriptor index */
177 #define SEGEX_IDX(s)	(((s)>>3)&0x1fff)
178 
179 /*
180  * Size of IDT table
181  */
182 
183 #define	NIDT	256		/* 32 reserved, 0x80 syscall, most are h/w */
184 #define	NRSVIDT	32		/* reserved entries for cpu exceptions */
185 
186 /*
187  * Entries in the Interrupt Descriptor Table (IDT)
188  */
189 #define	IDT_DE		0	/* #DE: Divide Error */
190 #define	IDT_DB		1	/* #DB: Debug */
191 #define	IDT_NMI		2	/* Nonmaskable External Interrupt */
192 #define	IDT_BP		3	/* #BP: Breakpoint */
193 #define	IDT_OF		4	/* #OF: Overflow */
194 #define	IDT_BR		5	/* #BR: Bound Range Exceeded */
195 #define	IDT_UD		6	/* #UD: Undefined/Invalid Opcode */
196 #define	IDT_NM		7	/* #NM: No Math Coprocessor */
197 #define	IDT_DF		8	/* #DF: Double Fault */
198 #define	IDT_FPUGP	9	/* Coprocessor Segment Overrun */
199 #define	IDT_TS		10	/* #TS: Invalid TSS */
200 #define	IDT_NP		11	/* #NP: Segment Not Present */
201 #define	IDT_SS		12	/* #SS: Stack Segment Fault */
202 #define	IDT_GP		13	/* #GP: General Protection Fault */
203 #define	IDT_PF		14	/* #PF: Page Fault */
204 #define	IDT_MF		16	/* #MF: FPU Floating-Point Error */
205 #define	IDT_AC		17	/* #AC: Alignment Check */
206 #define	IDT_MC		18	/* #MC: Machine Check */
207 #define	IDT_XF		19	/* #XF: SIMD Floating-Point Exception */
208 #define	IDT_IO_INTS	NRSVIDT	/* Base of IDT entries for I/O interrupts. */
209 #define	IDT_SYSCALL	0x80	/* System Call Interrupt Vector */
210 
211 /*
212  * Entries in the Global Descriptor Table (GDT)
213  * Note that each 4 entries share a single 32 byte L1 cache line.
214  * Some of the fast syscall instructions require a specific order here.
215  */
216 #define	GNULL_SEL	0	/* Null Descriptor */
217 #define	GPRIV_SEL	1	/* SMP Per-Processor Private Data */
218 #define	GUFS_SEL	2	/* User %fs Descriptor (order critical: 1) */
219 #define	GUGS_SEL	3	/* User %gs Descriptor (order critical: 2) */
220 #define	GCODE_SEL	4	/* Kernel Code Descriptor (order critical: 1) */
221 #define	GDATA_SEL	5	/* Kernel Data Descriptor (order critical: 2) */
222 #define	GUCODE_SEL	6	/* User Code Descriptor (order critical: 3) */
223 #define	GUDATA_SEL	7	/* User Data Descriptor (order critical: 4) */
224 #define	GBIOSLOWMEM_SEL	8	/* BIOS low memory access (must be entry 8) */
225 #define	GPROC0_SEL	9	/* Task state process slot zero and up */
226 #define	GLDT_SEL	10	/* Default User LDT */
227 #define	GUSERLDT_SEL	11	/* User LDT */
228 #define	GPANIC_SEL	12	/* Task state to consider panic from */
229 #define	GBIOSCODE32_SEL	13	/* BIOS interface (32bit Code) */
230 #define	GBIOSCODE16_SEL	14	/* BIOS interface (16bit Code) */
231 #define	GBIOSDATA_SEL	15	/* BIOS interface (Data) */
232 #define	GBIOSUTIL_SEL	16	/* BIOS interface (Utility) */
233 #define	GBIOSARGS_SEL	17	/* BIOS interface (Arguments) */
234 #define	GNDIS_SEL	18	/* For the NDIS layer */
235 
236 #ifdef XEN
237 #define	NGDT 		9
238 #else
239 #define	NGDT 		19
240 #endif
241 
242 /*
243  * Entries in the Local Descriptor Table (LDT)
244  */
245 #define	LSYS5CALLS_SEL	0	/* forced by intel BCS */
246 #define	LSYS5SIGR_SEL	1
247 #define	L43BSDCALLS_SEL	2	/* notyet */
248 #define	LUCODE_SEL	3
249 #define LSOL26CALLS_SEL	4	/* Solaris >= 2.6 system call gate */
250 #define	LUDATA_SEL	5
251 /* separate stack, es,fs,gs sels ? */
252 /* #define	LPOSIXCALLS_SEL	5*/	/* notyet */
253 #define LBSDICALLS_SEL	16	/* BSDI system call gate */
254 #define NLDT		(LBSDICALLS_SEL + 1)
255 
256 #ifdef _KERNEL
257 extern int	_default_ldt;
258 #ifdef XEN
259 extern union descriptor *gdt;
260 extern union descriptor *ldt;
261 #else
262 extern union descriptor gdt[];
263 extern union descriptor ldt[NLDT];
264 #endif
265 extern struct soft_segment_descriptor gdt_segs[];
266 extern struct gate_descriptor *idt;
267 extern struct region_descriptor r_gdt, r_idt;
268 
269 void	lgdt(struct region_descriptor *rdp);
270 void	sdtossd(struct segment_descriptor *sdp,
271 	    struct soft_segment_descriptor *ssdp);
272 void	ssdtosd(struct soft_segment_descriptor *ssdp,
273 	    struct segment_descriptor *sdp);
274 #endif /* _KERNEL */
275 
276 #endif /* !_MACHINE_SEGMENTS_H_ */
277