xref: /freebsd/sys/amd64/include/segments.h (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
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  * $FreeBSD$
37  */
38 
39 #ifndef _MACHINE_SEGMENTS_H_
40 #define	_MACHINE_SEGMENTS_H_
41 
42 /*
43  * AMD64 Segmentation Data Structures and definitions
44  */
45 
46 #include <x86/segments.h>
47 
48 /*
49  * System segment descriptors (128 bit wide)
50  */
51 struct	system_segment_descriptor {
52 	u_int64_t sd_lolimit:16;	/* segment extent (lsb) */
53 	u_int64_t sd_lobase:24;		/* segment base address (lsb) */
54 	u_int64_t sd_type:5;		/* segment type */
55 	u_int64_t sd_dpl:2;		/* segment descriptor priority level */
56 	u_int64_t sd_p:1;		/* segment descriptor present */
57 	u_int64_t sd_hilimit:4;		/* segment extent (msb) */
58 	u_int64_t sd_xx0:3;		/* unused */
59 	u_int64_t sd_gran:1;		/* limit granularity (byte/page units)*/
60 	u_int64_t sd_hibase:40 __packed;/* segment base address  (msb) */
61 	u_int64_t sd_xx1:8;
62 	u_int64_t sd_mbz:5;		/* MUST be zero */
63 	u_int64_t sd_xx2:19;
64 } __packed;
65 
66 /*
67  * Software definitions are in this convenient format,
68  * which are translated into inconvenient segment descriptors
69  * when needed to be used by the 386 hardware
70  */
71 
72 struct	soft_segment_descriptor {
73 	unsigned long ssd_base;		/* segment base address  */
74 	unsigned long ssd_limit;	/* segment extent */
75 	unsigned long ssd_type:5;	/* segment type */
76 	unsigned long ssd_dpl:2;	/* segment descriptor priority level */
77 	unsigned long ssd_p:1;		/* segment descriptor present */
78 	unsigned long ssd_long:1;	/* long mode (for %cs) */
79 	unsigned long ssd_def32:1;	/* default 32 vs 16 bit size */
80 	unsigned long ssd_gran:1;	/* limit granularity (byte/page units)*/
81 } __packed;
82 
83 /*
84  * region descriptors, used to load gdt/idt tables before segments yet exist.
85  */
86 struct region_descriptor {
87 	uint64_t rd_limit:16;		/* segment extent */
88 	uint64_t rd_base:64 __packed;	/* base address  */
89 } __packed;
90 
91 #ifdef _KERNEL
92 extern struct user_segment_descriptor gdt[];
93 extern struct soft_segment_descriptor gdt_segs[];
94 extern struct gate_descriptor *idt;
95 extern struct region_descriptor r_gdt, r_idt;
96 
97 void	lgdt(struct region_descriptor *rdp);
98 void	sdtossd(struct user_segment_descriptor *sdp,
99 	    struct soft_segment_descriptor *ssdp);
100 void	ssdtosd(struct soft_segment_descriptor *ssdp,
101 	    struct user_segment_descriptor *sdp);
102 void	ssdtosyssd(struct soft_segment_descriptor *ssdp,
103 	    struct system_segment_descriptor *sdp);
104 void	update_gdt_gsbase(struct thread *td, uint32_t base);
105 void	update_gdt_fsbase(struct thread *td, uint32_t base);
106 #endif /* _KERNEL */
107 
108 #endif /* !_MACHINE_SEGMENTS_H_ */
109