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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _ASM_SEGMENT_H
2#define _ASM_SEGMENT_H
3
4/*
5 * The layout of the per-CPU GDT under Linux:
6 *
7 * 0 - null
8 * 1 - reserved
9 * 2 - reserved
10 * 3 - reserved
11 *
12 * 4 - unused <==== new cacheline
13 * 5 - unused
14 *
15 * ------- start of TLS (Thread-Local Storage) segments:
16 *
17 * 6 - TLS segment #1 [ glibc's TLS segment ]
18 * 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
19 * 8 - TLS segment #3
20 * 9 - reserved
21 * 10 - reserved
22 * 11 - reserved
23 *
24 * ------- start of kernel segments:
25 *
26 * 12 - kernel code segment <==== new cacheline
27 * 13 - kernel data segment
28 * 14 - default user CS
29 * 15 - default user DS
30 * 16 - TSS
31 * 17 - LDT
32 * 18 - PNPBIOS support (16->32 gate)
33 * 19 - PNPBIOS support
34 * 20 - PNPBIOS support
35 * 21 - PNPBIOS support
36 * 22 - PNPBIOS support
37 * 23 - APM BIOS support
38 * 24 - APM BIOS support
39 * 25 - APM BIOS support
40 *
41 * 26 - ESPFIX small SS
42 * 27 - unused
43 * 28 - unused
44 * 29 - unused
45 * 30 - unused
46 * 31 - TSS for double fault handler
47 */
48#define GDT_ENTRY_TLS_ENTRIES 3
49#define GDT_ENTRY_TLS_MIN 6
50#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
51
52#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
53
54#define GDT_ENTRY_DEFAULT_USER_CS 14
55#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS * 8 + 3)
56
57#define GDT_ENTRY_DEFAULT_USER_DS 15
58#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS * 8 + 3)
59
60#define GDT_ENTRY_KERNEL_BASE 12
61
62#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE + 0)
63#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8)
64
65#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE + 1)
66#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8)
67
68#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE + 4)
69#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE + 5)
70
71#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 6)
72#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 11)
73
74#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14)
75#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
76
77#define GDT_ENTRY_DOUBLEFAULT_TSS 31
78
79/*
80 * The GDT has 32 entries
81 */
82#define GDT_ENTRIES 32
83
84#define GDT_SIZE (GDT_ENTRIES * 8)
85
86/* Simple and small GDT entries for booting only */
87
88#define GDT_ENTRY_BOOT_CS 2
89#define __BOOT_CS (GDT_ENTRY_BOOT_CS * 8)
90
91#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1)
92#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8)
93
Zachary Amsden5702d0f2006-01-06 00:11:51 -080094/* The PnP BIOS entries in the GDT */
95#define GDT_ENTRY_PNPBIOS_CS32 (GDT_ENTRY_PNPBIOS_BASE + 0)
96#define GDT_ENTRY_PNPBIOS_CS16 (GDT_ENTRY_PNPBIOS_BASE + 1)
97#define GDT_ENTRY_PNPBIOS_DS (GDT_ENTRY_PNPBIOS_BASE + 2)
98#define GDT_ENTRY_PNPBIOS_TS1 (GDT_ENTRY_PNPBIOS_BASE + 3)
99#define GDT_ENTRY_PNPBIOS_TS2 (GDT_ENTRY_PNPBIOS_BASE + 4)
100
101/* The PnP BIOS selectors */
102#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
103#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
104#define PNP_DS (GDT_ENTRY_PNPBIOS_DS * 8) /* data segment for BIOS */
105#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1 * 8) /* transfer data segment */
106#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2 * 8) /* another data segment */
107
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108/*
109 * The interrupt descriptor table has room for 256 idt's,
110 * the global descriptor table is dependent on the number
111 * of tasks we can have..
112 */
113#define IDT_ENTRIES 256
114
115#endif