Linux kernel mirror (for testing)
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linux
1#ifndef _ASM_X86_SEGMENT_H_
2#define _ASM_X86_SEGMENT_H_
3
4/* Constructor for a conventional segment GDT (or LDT) entry */
5/* This is a macro so it can be used in initializers */
6#define GDT_ENTRY(flags, base, limit) \
7 ((((base) & 0xff000000ULL) << (56-24)) | \
8 (((flags) & 0x0000f0ffULL) << 40) | \
9 (((limit) & 0x000f0000ULL) << (48-16)) | \
10 (((base) & 0x00ffffffULL) << 16) | \
11 (((limit) & 0x0000ffffULL)))
12
13/* Simple and small GDT entries for booting only */
14
15#define GDT_ENTRY_BOOT_CS 2
16#define __BOOT_CS (GDT_ENTRY_BOOT_CS * 8)
17
18#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1)
19#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8)
20
21#define GDT_ENTRY_BOOT_TSS (GDT_ENTRY_BOOT_CS + 2)
22#define __BOOT_TSS (GDT_ENTRY_BOOT_TSS * 8)
23
24#ifdef CONFIG_X86_32
25/*
26 * The layout of the per-CPU GDT under Linux:
27 *
28 * 0 - null
29 * 1 - reserved
30 * 2 - reserved
31 * 3 - reserved
32 *
33 * 4 - unused <==== new cacheline
34 * 5 - unused
35 *
36 * ------- start of TLS (Thread-Local Storage) segments:
37 *
38 * 6 - TLS segment #1 [ glibc's TLS segment ]
39 * 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
40 * 8 - TLS segment #3
41 * 9 - reserved
42 * 10 - reserved
43 * 11 - reserved
44 *
45 * ------- start of kernel segments:
46 *
47 * 12 - kernel code segment <==== new cacheline
48 * 13 - kernel data segment
49 * 14 - default user CS
50 * 15 - default user DS
51 * 16 - TSS
52 * 17 - LDT
53 * 18 - PNPBIOS support (16->32 gate)
54 * 19 - PNPBIOS support
55 * 20 - PNPBIOS support
56 * 21 - PNPBIOS support
57 * 22 - PNPBIOS support
58 * 23 - APM BIOS support
59 * 24 - APM BIOS support
60 * 25 - APM BIOS support
61 *
62 * 26 - ESPFIX small SS
63 * 27 - per-cpu [ offset to per-cpu data area ]
64 * 28 - unused
65 * 29 - unused
66 * 30 - unused
67 * 31 - TSS for double fault handler
68 */
69#define GDT_ENTRY_TLS_MIN 6
70#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
71
72#define GDT_ENTRY_DEFAULT_USER_CS 14
73
74#define GDT_ENTRY_DEFAULT_USER_DS 15
75
76#define GDT_ENTRY_KERNEL_BASE 12
77
78#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE + 0)
79
80#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE + 1)
81
82#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE + 4)
83#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE + 5)
84
85#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 6)
86#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 11)
87
88#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14)
89#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
90
91#define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE + 15)
92#ifdef CONFIG_SMP
93#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
94#else
95#define __KERNEL_PERCPU 0
96#endif
97
98#define GDT_ENTRY_DOUBLEFAULT_TSS 31
99
100/*
101 * The GDT has 32 entries
102 */
103#define GDT_ENTRIES 32
104
105/* The PnP BIOS entries in the GDT */
106#define GDT_ENTRY_PNPBIOS_CS32 (GDT_ENTRY_PNPBIOS_BASE + 0)
107#define GDT_ENTRY_PNPBIOS_CS16 (GDT_ENTRY_PNPBIOS_BASE + 1)
108#define GDT_ENTRY_PNPBIOS_DS (GDT_ENTRY_PNPBIOS_BASE + 2)
109#define GDT_ENTRY_PNPBIOS_TS1 (GDT_ENTRY_PNPBIOS_BASE + 3)
110#define GDT_ENTRY_PNPBIOS_TS2 (GDT_ENTRY_PNPBIOS_BASE + 4)
111
112/* The PnP BIOS selectors */
113#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
114#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
115#define PNP_DS (GDT_ENTRY_PNPBIOS_DS * 8) /* data segment for BIOS */
116#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1 * 8) /* transfer data segment */
117#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2 * 8) /* another data segment */
118
119/* Bottom two bits of selector give the ring privilege level */
120#define SEGMENT_RPL_MASK 0x3
121/* Bit 2 is table indicator (LDT/GDT) */
122#define SEGMENT_TI_MASK 0x4
123
124/* User mode is privilege level 3 */
125#define USER_RPL 0x3
126/* LDT segment has TI set, GDT has it cleared */
127#define SEGMENT_LDT 0x4
128#define SEGMENT_GDT 0x0
129
130/*
131 * Matching rules for certain types of segments.
132 */
133
134/* Matches only __KERNEL_CS, ignoring PnP / USER / APM segments */
135#define SEGMENT_IS_KERNEL_CODE(x) (((x) & 0xfc) == GDT_ENTRY_KERNEL_CS * 8)
136
137/* Matches __KERNEL_CS and __USER_CS (they must be 2 entries apart) */
138#define SEGMENT_IS_FLAT_CODE(x) (((x) & 0xec) == GDT_ENTRY_KERNEL_CS * 8)
139
140/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
141#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
142
143
144#else
145#include <asm/cache.h>
146
147#define GDT_ENTRY_KERNEL32_CS 1
148#define GDT_ENTRY_KERNEL_CS 2
149#define GDT_ENTRY_KERNEL_DS 3
150
151#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS * 8)
152
153/*
154 * we cannot use the same code segment descriptor for user and kernel
155 * -- not even in the long flat mode, because of different DPL /kkeil
156 * The segment offset needs to contain a RPL. Grr. -AK
157 * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
158 */
159#define GDT_ENTRY_DEFAULT_USER32_CS 4
160#define GDT_ENTRY_DEFAULT_USER_DS 5
161#define GDT_ENTRY_DEFAULT_USER_CS 6
162#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS * 8 + 3)
163#define __USER32_DS __USER_DS
164
165#define GDT_ENTRY_TSS 8 /* needs two entries */
166#define GDT_ENTRY_LDT 10 /* needs two entries */
167#define GDT_ENTRY_TLS_MIN 12
168#define GDT_ENTRY_TLS_MAX 14
169
170#define GDT_ENTRY_PER_CPU 15 /* Abused to load per CPU data from limit */
171#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU * 8 + 3)
172
173/* TLS indexes for 64bit - hardcoded in arch_prctl */
174#define FS_TLS 0
175#define GS_TLS 1
176
177#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
178#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
179
180#define GDT_ENTRIES 16
181
182#endif
183
184#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8)
185#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8)
186#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS* 8 + 3)
187#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS* 8 + 3)
188#ifndef CONFIG_PARAVIRT
189#define get_kernel_rpl() 0
190#endif
191
192/* User mode is privilege level 3 */
193#define USER_RPL 0x3
194/* LDT segment has TI set, GDT has it cleared */
195#define SEGMENT_LDT 0x4
196#define SEGMENT_GDT 0x0
197
198/* Bottom two bits of selector give the ring privilege level */
199#define SEGMENT_RPL_MASK 0x3
200/* Bit 2 is table indicator (LDT/GDT) */
201#define SEGMENT_TI_MASK 0x4
202
203#define IDT_ENTRIES 256
204#define NUM_EXCEPTION_VECTORS 32
205#define GDT_SIZE (GDT_ENTRIES * 8)
206#define GDT_ENTRY_TLS_ENTRIES 3
207#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
208
209#ifdef __KERNEL__
210#ifndef __ASSEMBLY__
211extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][10];
212#endif
213#endif
214
215#endif