xref: /titanic_50/usr/src/uts/i86pc/boot/boot_gdt.s (revision ff3124eff995e6cd8ebd8c6543648e0670920034)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#if defined(__lint)
30#pragma pack(1)
31struct {
32	uint16_t limit_low;
33	uint16_t base_low;
34	uint8_t base_middle;
35	uint8_t attr;
36	uint8_t attr_and_limit;
37	uint8_t base_high;
38} global_descriptor_table[8];
39struct {
40	uint16_t limit;	/* sizeof (global_descriptor_table) - 1 */
41	void     *base;	/* &global_descriptor_table */
42} gdt_info;
43#pragma pack()
44
45#else	/* __lint */
46
47	.align 16
48
49	/*
50	 * This must remain in sync with the entries in intel/sys/gdt.h; in
51	 * particular kmdb uses B64CODE_SEL or B32CODE_SEL in perpetuity for
52	 * its IDT entries (they're copied to the kernel's GDT in init_idt()).
53	 */
54
55global_descriptor_table:
56	.long   0
57	.long   0
58
59	/* GDT_B32DATA: 32 bit flat data descriptor */
60	.value  0xFFFF	/* segment limit 0..15 */
61	.value  0x0000	/* segment base 0..15 */
62	.byte   0x0	/* segment base 16..23 */
63	.byte   0x92	/* P = 1, read/write data */
64	.byte   0xCF	/* G=1, B=1, Limit (16..19)=1111 */
65	.byte   0x0	/* segment base 24..32 */
66
67	/* GDT_B32CODE 32 bit flat code descriptor */
68	.value  0xFFFF	/* segment limit 0..15 */
69	.value  0x0000	/* segment base 0..15 */
70	.byte   0x0	/* segment base 16..23 */
71	.byte   0x9E	/* P=1, code, exec, readable */
72	.byte   0xCF	/* G=1, D=1, Limit (16..19)=1111 */
73	.byte   0x0	/* segment base 24..32 */
74
75	/*
76	 * GDT_B16CODE 16 bit code descriptor for doing BIOS calls
77	 */
78	.value  0xFFFF	/* segment limit 0..15 */
79	.value  0x0000	/* segment base 0..15 */
80	.byte   0x0	/* segment base 16..23 */
81	.byte   0x9E	/* P=1, code, exec, readable */
82	.byte   0x0F	/* G=0, D=0, Limit (16..19)=1111 */
83	.byte   0x0	/* segment base 24..32 */
84
85	/*
86	 * GDT_B16DATA 16 bit data descriptor for doing BIOS calls
87	 */
88	.value  0xFFFF	/* segment limit 0..15 */
89	.value  0x0000	/* segment base 0..15 */
90	.byte   0x0	/* segment base 16..23 */
91	.byte   0x92	/* P = 1, read/write data */
92	.byte   0x4F	/* G=0, D=1, Limit (16..19)=1111 */
93	.byte   0x0	/* segment base 24..32 */
94
95	/* GDT_B64CODE: 64 bit flat code descriptor - only L bit has meaning */
96	.value  0xFFFF	/* segment limit 0..15 */
97	.value  0x0000	/* segment base 0..15 */
98	.byte   0x0	/* segment base 16..23 */
99	.byte   0x9E	/* P=1, code, exec, readable */
100	.byte   0xAF	/* G=1, D=0, L=1, Limit (16..19)=1111 */
101	.byte   0x0	/* segment base 24..32 */
102
103	/*
104	 * unused
105	 */
106	.long	0
107	.long	0
108
109	/*
110	 * GDT_BGSTMP -- an entry for kmdb to use during boot
111	 */
112	.long	0
113	.long	0
114
115gdt_info:
116	.value	gdt_info - global_descriptor_table - 1
117	.long	global_descriptor_table
118	.long   0		/* needed for 64 bit */
119
120#endif	/* __lint */
121