arch/x86/include/asm/segment.h

   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 - stack_canary-20                [ for stack protector ]
  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_STACK_CANARY          (GDT_ENTRY_KERNEL_BASE + 16)
  99 #ifdef CONFIG_CC_STACKPROTECTOR
 100 #define __KERNEL_STACK_CANARY           (GDT_ENTRY_STACK_CANARY * 8)
 101 #else
 102 #define __KERNEL_STACK_CANARY           0
 103 #endif
 104
 105 #define GDT_ENTRY_DOUBLEFAULT_TSS       31
 106
 107 /*
 108  * The GDT has 32 entries
 109  */
 110 #define GDT_ENTRIES 32
 111
 112 /* The PnP BIOS entries in the GDT */
 113 #define GDT_ENTRY_PNPBIOS_CS32          (GDT_ENTRY_PNPBIOS_BASE + 0)
 114 #define GDT_ENTRY_PNPBIOS_CS16          (GDT_ENTRY_PNPBIOS_BASE + 1)
 115 #define GDT_ENTRY_PNPBIOS_DS            (GDT_ENTRY_PNPBIOS_BASE + 2)
 116 #define GDT_ENTRY_PNPBIOS_TS1           (GDT_ENTRY_PNPBIOS_BASE + 3)
 117 #define GDT_ENTRY_PNPBIOS_TS2           (GDT_ENTRY_PNPBIOS_BASE + 4)
 118
 119 /* The PnP BIOS selectors */
 120 #define PNP_CS32   (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
 121 #define PNP_CS16   (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
 122 #define PNP_DS     (GDT_ENTRY_PNPBIOS_DS * 8)   /* data segment for BIOS */
 123 #define PNP_TS1    (GDT_ENTRY_PNPBIOS_TS1 * 8)  /* transfer data segment */
 124 #define PNP_TS2    (GDT_ENTRY_PNPBIOS_TS2 * 8)  /* another data segment */
 125
 126 /* Bottom two bits of selector give the ring privilege level */
 127 #define SEGMENT_RPL_MASK        0x3
 128 /* Bit 2 is table indicator (LDT/GDT) */
 129 #define SEGMENT_TI_MASK         0x4
 130
 131 /* User mode is privilege level 3 */
 132 #define USER_RPL                0x3
 133 /* LDT segment has TI set, GDT has it cleared */
 134 #define SEGMENT_LDT             0x4
 135 #define SEGMENT_GDT             0x0
 136
 137 /*
 138  * Matching rules for certain types of segments.
 139  */
 140
 141 /* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
 142 #define SEGMENT_IS_PNP_CODE(x)   (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
 143
 144
 145 #else
 146 #include <asm/cache.h>
 147
 148 #define GDT_ENTRY_KERNEL32_CS 1
 149 #define GDT_ENTRY_KERNEL_CS 2
 150 #define GDT_ENTRY_KERNEL_DS 3
 151
 152 #define __KERNEL32_CS   (GDT_ENTRY_KERNEL32_CS * 8)
 153
 154 /*
 155  * we cannot use the same code segment descriptor for user and kernel
 156  * -- not even in the long flat mode, because of different DPL /kkeil
 157  * The segment offset needs to contain a RPL. Grr. -AK
 158  * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
 159  */
 160 #define GDT_ENTRY_DEFAULT_USER32_CS 4
 161 #define GDT_ENTRY_DEFAULT_USER_DS 5
 162 #define GDT_ENTRY_DEFAULT_USER_CS 6
 163 #define __USER32_CS   (GDT_ENTRY_DEFAULT_USER32_CS * 8 + 3)
 164 #define __USER32_DS     __USER_DS
 165
 166 #define GDT_ENTRY_TSS 8 /* needs two entries */
 167 #define GDT_ENTRY_LDT 10 /* needs two entries */
 168 #define GDT_ENTRY_TLS_MIN 12
 169 #define GDT_ENTRY_TLS_MAX 14
 170
 171 #define GDT_ENTRY_PER_CPU 15    /* Abused to load per CPU data from limit */
 172 #define __PER_CPU_SEG   (GDT_ENTRY_PER_CPU * 8 + 3)
 173
 174 /* TLS indexes for 64bit - hardcoded in arch_prctl */
 175 #define FS_TLS 0
 176 #define GS_TLS 1
 177
 178 #define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
 179 #define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
 180
 181 #define GDT_ENTRIES 16
 182
 183 #endif
 184
 185 #define __KERNEL_CS     (GDT_ENTRY_KERNEL_CS * 8)
 186 #define __KERNEL_DS     (GDT_ENTRY_KERNEL_DS * 8)
 187 #define __USER_DS     (GDT_ENTRY_DEFAULT_USER_DS* 8 + 3)
 188 #define __USER_CS     (GDT_ENTRY_DEFAULT_USER_CS* 8 + 3)
 189 #ifndef CONFIG_PARAVIRT
 190 #define get_kernel_rpl()  0
 191 #endif
 192
 193 /* User mode is privilege level 3 */
 194 #define USER_RPL                0x3
 195 /* LDT segment has TI set, GDT has it cleared */
 196 #define SEGMENT_LDT             0x4
 197 #define SEGMENT_GDT             0x0
 198
 199 /* Bottom two bits of selector give the ring privilege level */
 200 #define SEGMENT_RPL_MASK        0x3
 201 /* Bit 2 is table indicator (LDT/GDT) */
 202 #define SEGMENT_TI_MASK         0x4
 203
 204 #define IDT_ENTRIES 256
 205 #define NUM_EXCEPTION_VECTORS 32
 206 #define GDT_SIZE (GDT_ENTRIES * 8)
 207 #define GDT_ENTRY_TLS_ENTRIES 3
 208 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
 209
 210 #ifdef __KERNEL__
 211 #ifndef __ASSEMBLY__
 212 extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][10];
 213 #endif
 214 #endif
 215
 216 #endif /* _ASM_X86_SEGMENT_H */