xref: /freebsd/sys/i386/include/segments.h (revision 282a3889ebf826db9839be296ff1dd903f6d6d6e)
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 #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  * Memory and System segment descriptors
60  */
61 struct	segment_descriptor	{
62 	unsigned sd_lolimit:16 ;	/* segment extent (lsb) */
63 	unsigned sd_lobase:24 __packed;	/* segment base address (lsb) */
64 	unsigned sd_type:5 ;		/* segment type */
65 	unsigned sd_dpl:2 ;		/* segment descriptor priority level */
66 	unsigned sd_p:1 ;		/* segment descriptor present */
67 	unsigned sd_hilimit:4 ;		/* segment extent (msb) */
68 	unsigned sd_xx:2 ;		/* unused */
69 	unsigned sd_def32:1 ;		/* default 32 vs 16 bit size */
70 	unsigned sd_gran:1 ;		/* limit granularity (byte/page units)*/
71 	unsigned sd_hibase:8 ;		/* segment base address  (msb) */
72 } ;
73 
74 /*
75  * Gate descriptors (e.g. indirect descriptors)
76  */
77 struct	gate_descriptor	{
78 	unsigned gd_looffset:16 ;	/* gate offset (lsb) */
79 	unsigned gd_selector:16 ;	/* gate segment selector */
80 	unsigned gd_stkcpy:5 ;		/* number of stack wds to cpy */
81 	unsigned gd_xx:3 ;		/* unused */
82 	unsigned gd_type:5 ;		/* segment type */
83 	unsigned gd_dpl:2 ;		/* segment descriptor priority level */
84 	unsigned gd_p:1 ;		/* segment descriptor present */
85 	unsigned gd_hioffset:16 ;	/* gate offset (msb) */
86 } ;
87 
88 /*
89  * Generic descriptor
90  */
91 union	descriptor	{
92 	struct	segment_descriptor sd;
93 	struct	gate_descriptor gd;
94 };
95 
96 	/* system segments and gate types */
97 #define	SDT_SYSNULL	 0	/* system null */
98 #define	SDT_SYS286TSS	 1	/* system 286 TSS available */
99 #define	SDT_SYSLDT	 2	/* system local descriptor table */
100 #define	SDT_SYS286BSY	 3	/* system 286 TSS busy */
101 #define	SDT_SYS286CGT	 4	/* system 286 call gate */
102 #define	SDT_SYSTASKGT	 5	/* system task gate */
103 #define	SDT_SYS286IGT	 6	/* system 286 interrupt gate */
104 #define	SDT_SYS286TGT	 7	/* system 286 trap gate */
105 #define	SDT_SYSNULL2	 8	/* system null again */
106 #define	SDT_SYS386TSS	 9	/* system 386 TSS available */
107 #define	SDT_SYSNULL3	10	/* system null again */
108 #define	SDT_SYS386BSY	11	/* system 386 TSS busy */
109 #define	SDT_SYS386CGT	12	/* system 386 call gate */
110 #define	SDT_SYSNULL4	13	/* system null again */
111 #define	SDT_SYS386IGT	14	/* system 386 interrupt gate */
112 #define	SDT_SYS386TGT	15	/* system 386 trap gate */
113 
114 	/* memory segment types */
115 #define	SDT_MEMRO	16	/* memory read only */
116 #define	SDT_MEMROA	17	/* memory read only accessed */
117 #define	SDT_MEMRW	18	/* memory read write */
118 #define	SDT_MEMRWA	19	/* memory read write accessed */
119 #define	SDT_MEMROD	20	/* memory read only expand dwn limit */
120 #define	SDT_MEMRODA	21	/* memory read only expand dwn limit accessed */
121 #define	SDT_MEMRWD	22	/* memory read write expand dwn limit */
122 #define	SDT_MEMRWDA	23	/* memory read write expand dwn limit accessed */
123 #define	SDT_MEME	24	/* memory execute only */
124 #define	SDT_MEMEA	25	/* memory execute only accessed */
125 #define	SDT_MEMER	26	/* memory execute read */
126 #define	SDT_MEMERA	27	/* memory execute read accessed */
127 #define	SDT_MEMEC	28	/* memory execute only conforming */
128 #define	SDT_MEMEAC	29	/* memory execute only accessed conforming */
129 #define	SDT_MEMERC	30	/* memory execute read conforming */
130 #define	SDT_MEMERAC	31	/* memory execute read accessed conforming */
131 
132 /*
133  * Software definitions are in this convenient format,
134  * which are translated into inconvenient segment descriptors
135  * when needed to be used by the 386 hardware
136  */
137 
138 struct	soft_segment_descriptor	{
139 	unsigned ssd_base ;		/* segment base address  */
140 	unsigned ssd_limit ;		/* segment extent */
141 	unsigned ssd_type:5 ;		/* segment type */
142 	unsigned ssd_dpl:2 ;		/* segment descriptor priority level */
143 	unsigned ssd_p:1 ;		/* segment descriptor present */
144 	unsigned ssd_xx:4 ;		/* unused */
145 	unsigned ssd_xx1:2 ;		/* unused */
146 	unsigned ssd_def32:1 ;		/* default 32 vs 16 bit size */
147 	unsigned ssd_gran:1 ;		/* limit granularity (byte/page units)*/
148 };
149 
150 /*
151  * region descriptors, used to load gdt/idt tables before segments yet exist.
152  */
153 struct region_descriptor {
154 	unsigned rd_limit:16;		/* segment extent */
155 	unsigned rd_base:32 __packed;	/* base address  */
156 };
157 
158 /*
159  * Segment Protection Exception code bits
160  */
161 
162 #define	SEGEX_EXT	0x01	/* recursive or externally induced */
163 #define	SEGEX_IDT	0x02	/* interrupt descriptor table */
164 #define	SEGEX_TI	0x04	/* local descriptor table */
165 				/* other bits are affected descriptor index */
166 #define SEGEX_IDX(s)	(((s)>>3)&0x1fff)
167 
168 /*
169  * Size of IDT table
170  */
171 
172 #define	NIDT	256		/* 32 reserved, 0x80 syscall, most are h/w */
173 #define	NRSVIDT	32		/* reserved entries for cpu exceptions */
174 
175 /*
176  * Entries in the Interrupt Descriptor Table (IDT)
177  */
178 #define	IDT_DE		0	/* #DE: Divide Error */
179 #define	IDT_DB		1	/* #DB: Debug */
180 #define	IDT_NMI		2	/* Nonmaskable External Interrupt */
181 #define	IDT_BP		3	/* #BP: Breakpoint */
182 #define	IDT_OF		4	/* #OF: Overflow */
183 #define	IDT_BR		5	/* #BR: Bound Range Exceeded */
184 #define	IDT_UD		6	/* #UD: Undefined/Invalid Opcode */
185 #define	IDT_NM		7	/* #NM: No Math Coprocessor */
186 #define	IDT_DF		8	/* #DF: Double Fault */
187 #define	IDT_FPUGP	9	/* Coprocessor Segment Overrun */
188 #define	IDT_TS		10	/* #TS: Invalid TSS */
189 #define	IDT_NP		11	/* #NP: Segment Not Present */
190 #define	IDT_SS		12	/* #SS: Stack Segment Fault */
191 #define	IDT_GP		13	/* #GP: General Protection Fault */
192 #define	IDT_PF		14	/* #PF: Page Fault */
193 #define	IDT_MF		16	/* #MF: FPU Floating-Point Error */
194 #define	IDT_AC		17	/* #AC: Alignment Check */
195 #define	IDT_MC		18	/* #MC: Machine Check */
196 #define	IDT_XF		19	/* #XF: SIMD Floating-Point Exception */
197 #define	IDT_IO_INTS	NRSVIDT	/* Base of IDT entries for I/O interrupts. */
198 #define	IDT_SYSCALL	0x80	/* System Call Interrupt Vector */
199 
200 /*
201  * Entries in the Global Descriptor Table (GDT)
202  * Note that each 4 entries share a single 32 byte L1 cache line.
203  * Some of the fast syscall instructions require a specific order here.
204  */
205 #define	GNULL_SEL	0	/* Null Descriptor */
206 #define	GPRIV_SEL	1	/* SMP Per-Processor Private Data */
207 #define	GUFS_SEL	2	/* User %fs Descriptor (order critical: 1) */
208 #define	GUGS_SEL	3	/* User %gs Descriptor (order critical: 2) */
209 #define	GCODE_SEL	4	/* Kernel Code Descriptor (order critical: 1) */
210 #define	GDATA_SEL	5	/* Kernel Data Descriptor (order critical: 2) */
211 #define	GUCODE_SEL	6	/* User Code Descriptor (order critical: 3) */
212 #define	GUDATA_SEL	7	/* User Data Descriptor (order critical: 4) */
213 #define	GBIOSLOWMEM_SEL	8	/* BIOS low memory access (must be entry 8) */
214 #define	GPROC0_SEL	9	/* Task state process slot zero and up */
215 #define	GLDT_SEL	10	/* Default User LDT */
216 #define	GUSERLDT_SEL	11	/* User LDT */
217 #define	GPANIC_SEL	12	/* Task state to consider panic from */
218 #define	GBIOSCODE32_SEL	13	/* BIOS interface (32bit Code) */
219 #define	GBIOSCODE16_SEL	14	/* BIOS interface (16bit Code) */
220 #define	GBIOSDATA_SEL	15	/* BIOS interface (Data) */
221 #define	GBIOSUTIL_SEL	16	/* BIOS interface (Utility) */
222 #define	GBIOSARGS_SEL	17	/* BIOS interface (Arguments) */
223 #define	GNDIS_SEL	18	/* For the NDIS layer */
224 
225 #define	NGDT 		19
226 
227 /*
228  * Entries in the Local Descriptor Table (LDT)
229  */
230 #define	LSYS5CALLS_SEL	0	/* forced by intel BCS */
231 #define	LSYS5SIGR_SEL	1
232 #define	L43BSDCALLS_SEL	2	/* notyet */
233 #define	LUCODE_SEL	3
234 #define LSOL26CALLS_SEL	4	/* Solaris >= 2.6 system call gate */
235 #define	LUDATA_SEL	5
236 /* separate stack, es,fs,gs sels ? */
237 /* #define	LPOSIXCALLS_SEL	5*/	/* notyet */
238 #define LBSDICALLS_SEL	16	/* BSDI system call gate */
239 #define NLDT		(LBSDICALLS_SEL + 1)
240 
241 #ifdef _KERNEL
242 extern int	_default_ldt;
243 extern union descriptor gdt[];
244 extern struct soft_segment_descriptor gdt_segs[];
245 extern struct gate_descriptor *idt;
246 extern union descriptor ldt[NLDT];
247 extern struct region_descriptor r_gdt, r_idt;
248 
249 void	lgdt(struct region_descriptor *rdp);
250 void	sdtossd(struct segment_descriptor *sdp,
251 	    struct soft_segment_descriptor *ssdp);
252 void	ssdtosd(struct soft_segment_descriptor *ssdp,
253 	    struct segment_descriptor *sdp);
254 #endif /* _KERNEL */
255 
256 #endif /* !_MACHINE_SEGMENTS_H_ */
257