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Linux/arch/x86/include/asm/segment.h

  1 #ifndef _ASM_X86_SEGMENT_H
  2 #define _ASM_X86_SEGMENT_H
  3 
  4 #include <linux/const.h>
  5 
  6 /* Constructor for a conventional segment GDT (or LDT) entry */
  7 /* This is a macro so it can be used in initializers */
  8 #define GDT_ENTRY(flags, base, limit)                   \
  9         ((((base)  & _AC(0xff000000,ULL)) << (56-24)) | \
 10          (((flags) & _AC(0x0000f0ff,ULL)) << 40) |      \
 11          (((limit) & _AC(0x000f0000,ULL)) << (48-16)) | \
 12          (((base)  & _AC(0x00ffffff,ULL)) << 16) |      \
 13          (((limit) & _AC(0x0000ffff,ULL))))
 14 
 15 /* Simple and small GDT entries for booting only */
 16 
 17 #define GDT_ENTRY_BOOT_CS       2
 18 #define __BOOT_CS               (GDT_ENTRY_BOOT_CS * 8)
 19 
 20 #define GDT_ENTRY_BOOT_DS       (GDT_ENTRY_BOOT_CS + 1)
 21 #define __BOOT_DS               (GDT_ENTRY_BOOT_DS * 8)
 22 
 23 #define GDT_ENTRY_BOOT_TSS      (GDT_ENTRY_BOOT_CS + 2)
 24 #define __BOOT_TSS              (GDT_ENTRY_BOOT_TSS * 8)
 25 
 26 #ifdef CONFIG_X86_32
 27 /*
 28  * The layout of the per-CPU GDT under Linux:
 29  *
 30  *   0 - null
 31  *   1 - reserved
 32  *   2 - reserved
 33  *   3 - reserved
 34  *
 35  *   4 - unused                 <==== new cacheline
 36  *   5 - unused
 37  *
 38  *  ------- start of TLS (Thread-Local Storage) segments:
 39  *
 40  *   6 - TLS segment #1                 [ glibc's TLS segment ]
 41  *   7 - TLS segment #2                 [ Wine's %fs Win32 segment ]
 42  *   8 - TLS segment #3
 43  *   9 - reserved
 44  *  10 - reserved
 45  *  11 - reserved
 46  *
 47  *  ------- start of kernel segments:
 48  *
 49  *  12 - kernel code segment            <==== new cacheline
 50  *  13 - kernel data segment
 51  *  14 - default user CS
 52  *  15 - default user DS
 53  *  16 - TSS
 54  *  17 - LDT
 55  *  18 - PNPBIOS support (16->32 gate)
 56  *  19 - PNPBIOS support
 57  *  20 - PNPBIOS support
 58  *  21 - PNPBIOS support
 59  *  22 - PNPBIOS support
 60  *  23 - APM BIOS support
 61  *  24 - APM BIOS support
 62  *  25 - APM BIOS support
 63  *
 64  *  26 - ESPFIX small SS
 65  *  27 - per-cpu                        [ offset to per-cpu data area ]
 66  *  28 - stack_canary-20                [ for stack protector ]
 67  *  29 - unused
 68  *  30 - unused
 69  *  31 - TSS for double fault handler
 70  */
 71 #define GDT_ENTRY_TLS_MIN       6
 72 #define GDT_ENTRY_TLS_MAX       (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
 73 
 74 #define GDT_ENTRY_DEFAULT_USER_CS       14
 75 
 76 #define GDT_ENTRY_DEFAULT_USER_DS       15
 77 
 78 #define GDT_ENTRY_KERNEL_BASE           (12)
 79 
 80 #define GDT_ENTRY_KERNEL_CS             (GDT_ENTRY_KERNEL_BASE+0)
 81 
 82 #define GDT_ENTRY_KERNEL_DS             (GDT_ENTRY_KERNEL_BASE+1)
 83 
 84 #define GDT_ENTRY_TSS                   (GDT_ENTRY_KERNEL_BASE+4)
 85 #define GDT_ENTRY_LDT                   (GDT_ENTRY_KERNEL_BASE+5)
 86 
 87 #define GDT_ENTRY_PNPBIOS_BASE          (GDT_ENTRY_KERNEL_BASE+6)
 88 #define GDT_ENTRY_APMBIOS_BASE          (GDT_ENTRY_KERNEL_BASE+11)
 89 
 90 #define GDT_ENTRY_ESPFIX_SS             (GDT_ENTRY_KERNEL_BASE+14)
 91 #define __ESPFIX_SS                     (GDT_ENTRY_ESPFIX_SS*8)
 92 
 93 #define GDT_ENTRY_PERCPU                (GDT_ENTRY_KERNEL_BASE+15)
 94 #ifdef CONFIG_SMP
 95 #define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
 96 #else
 97 #define __KERNEL_PERCPU 0
 98 #endif
 99 
100 #define GDT_ENTRY_STACK_CANARY          (GDT_ENTRY_KERNEL_BASE+16)
101 #ifdef CONFIG_CC_STACKPROTECTOR
102 #define __KERNEL_STACK_CANARY           (GDT_ENTRY_STACK_CANARY*8)
103 #else
104 #define __KERNEL_STACK_CANARY           0
105 #endif
106 
107 #define GDT_ENTRY_DOUBLEFAULT_TSS       31
108 
109 /*
110  * The GDT has 32 entries
111  */
112 #define GDT_ENTRIES 32
113 
114 /* The PnP BIOS entries in the GDT */
115 #define GDT_ENTRY_PNPBIOS_CS32          (GDT_ENTRY_PNPBIOS_BASE + 0)
116 #define GDT_ENTRY_PNPBIOS_CS16          (GDT_ENTRY_PNPBIOS_BASE + 1)
117 #define GDT_ENTRY_PNPBIOS_DS            (GDT_ENTRY_PNPBIOS_BASE + 2)
118 #define GDT_ENTRY_PNPBIOS_TS1           (GDT_ENTRY_PNPBIOS_BASE + 3)
119 #define GDT_ENTRY_PNPBIOS_TS2           (GDT_ENTRY_PNPBIOS_BASE + 4)
120 
121 /* The PnP BIOS selectors */
122 #define PNP_CS32   (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
123 #define PNP_CS16   (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
124 #define PNP_DS     (GDT_ENTRY_PNPBIOS_DS * 8)   /* data segment for BIOS */
125 #define PNP_TS1    (GDT_ENTRY_PNPBIOS_TS1 * 8)  /* transfer data segment */
126 #define PNP_TS2    (GDT_ENTRY_PNPBIOS_TS2 * 8)  /* another data segment */
127 
128 /* Bottom two bits of selector give the ring privilege level */
129 #define SEGMENT_RPL_MASK        0x3
130 /* Bit 2 is table indicator (LDT/GDT) */
131 #define SEGMENT_TI_MASK         0x4
132 
133 /* User mode is privilege level 3 */
134 #define USER_RPL                0x3
135 /* LDT segment has TI set, GDT has it cleared */
136 #define SEGMENT_LDT             0x4
137 #define SEGMENT_GDT             0x0
138 
139 /*
140  * Matching rules for certain types of segments.
141  */
142 
143 /* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
144 #define SEGMENT_IS_PNP_CODE(x)   (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
145 
146 
147 #else
148 #include <asm/cache.h>
149 
150 #define GDT_ENTRY_KERNEL32_CS 1
151 #define GDT_ENTRY_KERNEL_CS 2
152 #define GDT_ENTRY_KERNEL_DS 3
153 
154 #define __KERNEL32_CS   (GDT_ENTRY_KERNEL32_CS * 8)
155 
156 /*
157  * we cannot use the same code segment descriptor for user and kernel
158  * -- not even in the long flat mode, because of different DPL /kkeil
159  * The segment offset needs to contain a RPL. Grr. -AK
160  * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
161  */
162 #define GDT_ENTRY_DEFAULT_USER32_CS 4
163 #define GDT_ENTRY_DEFAULT_USER_DS 5
164 #define GDT_ENTRY_DEFAULT_USER_CS 6
165 #define __USER32_CS   (GDT_ENTRY_DEFAULT_USER32_CS * 8 + 3)
166 #define __USER32_DS     __USER_DS
167 
168 #define GDT_ENTRY_TSS 8 /* needs two entries */
169 #define GDT_ENTRY_LDT 10 /* needs two entries */
170 #define GDT_ENTRY_TLS_MIN 12
171 #define GDT_ENTRY_TLS_MAX 14
172 
173 #define GDT_ENTRY_PER_CPU 15    /* Abused to load per CPU data from limit */
174 #define __PER_CPU_SEG   (GDT_ENTRY_PER_CPU * 8 + 3)
175 
176 /* TLS indexes for 64bit - hardcoded in arch_prctl */
177 #define FS_TLS 0
178 #define GS_TLS 1
179 
180 #define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
181 #define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
182 
183 #define GDT_ENTRIES 16
184 
185 #endif
186 
187 #define __KERNEL_CS     (GDT_ENTRY_KERNEL_CS*8)
188 #define __KERNEL_DS     (GDT_ENTRY_KERNEL_DS*8)
189 #define __USER_DS       (GDT_ENTRY_DEFAULT_USER_DS*8+3)
190 #define __USER_CS       (GDT_ENTRY_DEFAULT_USER_CS*8+3)
191 #ifndef CONFIG_PARAVIRT
192 #define get_kernel_rpl()  0
193 #endif
194 
195 /* User mode is privilege level 3 */
196 #define USER_RPL                0x3
197 /* LDT segment has TI set, GDT has it cleared */
198 #define SEGMENT_LDT             0x4
199 #define SEGMENT_GDT             0x0
200 
201 /* Bottom two bits of selector give the ring privilege level */
202 #define SEGMENT_RPL_MASK        0x3
203 /* Bit 2 is table indicator (LDT/GDT) */
204 #define SEGMENT_TI_MASK         0x4
205 
206 #define IDT_ENTRIES 256
207 #define NUM_EXCEPTION_VECTORS 32
208 #define GDT_SIZE (GDT_ENTRIES * 8)
209 #define GDT_ENTRY_TLS_ENTRIES 3
210 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
211 
212 #ifdef __KERNEL__
213 #ifndef __ASSEMBLY__
214 extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][10];
215 #endif
216 #endif
217 
218 #endif /* _ASM_X86_SEGMENT_H */
219 

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