include/asm-x86/segment.h

   1 #ifndef _ASM_X86_SEGMENT_H_
   2 #define _ASM_X86_SEGMENT_H_
   3
   4 /* Simple and small GDT entries for booting only */
   5
   6 #define GDT_ENTRY_BOOT_CS       2
   7 #define __BOOT_CS               (GDT_ENTRY_BOOT_CS * 8)
   8
   9 #define GDT_ENTRY_BOOT_DS       (GDT_ENTRY_BOOT_CS + 1)
  10 #define __BOOT_DS               (GDT_ENTRY_BOOT_DS * 8)
  11
  12 #define GDT_ENTRY_BOOT_TSS      (GDT_ENTRY_BOOT_CS + 2)
  13 #define __BOOT_TSS              (GDT_ENTRY_BOOT_TSS * 8)
  14
  15 #ifdef CONFIG_X86_32
  16 /*
  17  * The layout of the per-CPU GDT under Linux:
  18  *
  19  *   0 - null
  20  *   1 - reserved
  21  *   2 - reserved
  22  *   3 - reserved
  23  *
  24  *   4 - unused                 <==== new cacheline
  25  *   5 - unused
  26  *
  27  *  ------- start of TLS (Thread-Local Storage) segments:
  28  *
  29  *   6 - TLS segment #1                 [ glibc's TLS segment ]
  30  *   7 - TLS segment #2                 [ Wine's %fs Win32 segment ]
  31  *   8 - TLS segment #3
  32  *   9 - reserved
  33  *  10 - reserved
  34  *  11 - reserved
  35  *
  36  *  ------- start of kernel segments:
  37  *
  38  *  12 - kernel code segment            <==== new cacheline
  39  *  13 - kernel data segment
  40  *  14 - default user CS
  41  *  15 - default user DS
  42  *  16 - TSS
  43  *  17 - LDT
  44  *  18 - PNPBIOS support (16->32 gate)
  45  *  19 - PNPBIOS support
  46  *  20 - PNPBIOS support
  47  *  21 - PNPBIOS support
  48  *  22 - PNPBIOS support
  49  *  23 - APM BIOS support
  50  *  24 - APM BIOS support
  51  *  25 - APM BIOS support
  52  *
  53  *  26 - ESPFIX small SS
  54  *  27 - per-cpu                        [ offset to per-cpu data area ]
  55  *  28 - unused
  56  *  29 - unused
  57  *  30 - unused
  58  *  31 - TSS for double fault handler
  59  */
  60 #define GDT_ENTRY_TLS_MIN       6
  61 #define GDT_ENTRY_TLS_MAX       (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
  62
  63 #define GDT_ENTRY_DEFAULT_USER_CS       14
  64 #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS * 8 + 3)
  65
  66 #define GDT_ENTRY_DEFAULT_USER_DS       15
  67 #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS * 8 + 3)
  68
  69 #define GDT_ENTRY_KERNEL_BASE   12
  70
  71 #define GDT_ENTRY_KERNEL_CS             (GDT_ENTRY_KERNEL_BASE + 0)
  72 #define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8)
  73
  74 #define GDT_ENTRY_KERNEL_DS             (GDT_ENTRY_KERNEL_BASE + 1)
  75 #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8)
  76
  77 #define GDT_ENTRY_TSS                   (GDT_ENTRY_KERNEL_BASE + 4)
  78 #define GDT_ENTRY_LDT                   (GDT_ENTRY_KERNEL_BASE + 5)
  79
  80 #define GDT_ENTRY_PNPBIOS_BASE          (GDT_ENTRY_KERNEL_BASE + 6)
  81 #define GDT_ENTRY_APMBIOS_BASE          (GDT_ENTRY_KERNEL_BASE + 11)
  82
  83 #define GDT_ENTRY_ESPFIX_SS             (GDT_ENTRY_KERNEL_BASE + 14)
  84 #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
  85
  86 #define GDT_ENTRY_PERCPU                        (GDT_ENTRY_KERNEL_BASE + 15)
  87 #ifdef CONFIG_SMP
  88 #define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
  89 #else
  90 #define __KERNEL_PERCPU 0
  91 #endif
  92
  93 #define GDT_ENTRY_DOUBLEFAULT_TSS       31
  94
  95 /*
  96  * The GDT has 32 entries
  97  */
  98 #define GDT_ENTRIES 32
  99
 100 /* The PnP BIOS entries in the GDT */
 101 #define GDT_ENTRY_PNPBIOS_CS32          (GDT_ENTRY_PNPBIOS_BASE + 0)
 102 #define GDT_ENTRY_PNPBIOS_CS16          (GDT_ENTRY_PNPBIOS_BASE + 1)
 103 #define GDT_ENTRY_PNPBIOS_DS            (GDT_ENTRY_PNPBIOS_BASE + 2)
 104 #define GDT_ENTRY_PNPBIOS_TS1           (GDT_ENTRY_PNPBIOS_BASE + 3)
 105 #define GDT_ENTRY_PNPBIOS_TS2           (GDT_ENTRY_PNPBIOS_BASE + 4)
 106
 107 /* The PnP BIOS selectors */
 108 #define PNP_CS32   (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
 109 #define PNP_CS16   (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
 110 #define PNP_DS     (GDT_ENTRY_PNPBIOS_DS * 8)   /* data segment for BIOS */
 111 #define PNP_TS1    (GDT_ENTRY_PNPBIOS_TS1 * 8)  /* transfer data segment */
 112 #define PNP_TS2    (GDT_ENTRY_PNPBIOS_TS2 * 8)  /* another data segment */
 113
 114 /* Bottom two bits of selector give the ring privilege level */
 115 #define SEGMENT_RPL_MASK        0x3
 116 /* Bit 2 is table indicator (LDT/GDT) */
 117 #define SEGMENT_TI_MASK         0x4
 118
 119 /* User mode is privilege level 3 */
 120 #define USER_RPL                0x3
 121 /* LDT segment has TI set, GDT has it cleared */
 122 #define SEGMENT_LDT             0x4
 123 #define SEGMENT_GDT             0x0
 124
 125 /*
 126  * Matching rules for certain types of segments.
 127  */
 128
 129 /* Matches only __KERNEL_CS, ignoring PnP / USER / APM segments */
 130 #define SEGMENT_IS_KERNEL_CODE(x) (((x) & 0xfc) == GDT_ENTRY_KERNEL_CS * 8)
 131
 132 /* Matches __KERNEL_CS and __USER_CS (they must be 2 entries apart) */
 133 #define SEGMENT_IS_FLAT_CODE(x)  (((x) & 0xec) == GDT_ENTRY_KERNEL_CS * 8)
 134
 135 /* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
 136 #define SEGMENT_IS_PNP_CODE(x)   (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
 137
 138
 139 #else
 140 #include <asm/cache.h>
 141
 142 #define __KERNEL_CS     0x10
 143 #define __KERNEL_DS     0x18
 144
 145 #define __KERNEL32_CS   0x08
 146
 147 /*
 148  * we cannot use the same code segment descriptor for user and kernel
 149  * -- not even in the long flat mode, because of different DPL /kkeil
 150  * The segment offset needs to contain a RPL. Grr. -AK
 151  * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
 152  */
 153
 154 #define __USER32_CS   0x23   /* 4*8+3 */
 155 #define __USER_DS     0x2b   /* 5*8+3 */
 156 #define __USER_CS     0x33   /* 6*8+3 */
 157 #define __USER32_DS     __USER_DS
 158
 159 #define GDT_ENTRY_TSS 8 /* needs two entries */
 160 #define GDT_ENTRY_LDT 10 /* needs two entries */
 161 #define GDT_ENTRY_TLS_MIN 12
 162 #define GDT_ENTRY_TLS_MAX 14
 163
 164 #define GDT_ENTRY_PER_CPU 15    /* Abused to load per CPU data from limit */
 165 #define __PER_CPU_SEG   (GDT_ENTRY_PER_CPU * 8 + 3)
 166
 167 /* TLS indexes for 64bit - hardcoded in arch_prctl */
 168 #define FS_TLS 0
 169 #define GS_TLS 1
 170
 171 #define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
 172 #define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
 173
 174 #define GDT_ENTRIES 16
 175
 176 #endif
 177
 178 #ifndef CONFIG_PARAVIRT
 179 #define get_kernel_rpl()  0
 180 #endif
 181
 182 /* User mode is privilege level 3 */
 183 #define USER_RPL                0x3
 184 /* LDT segment has TI set, GDT has it cleared */
 185 #define SEGMENT_LDT             0x4
 186 #define SEGMENT_GDT             0x0
 187
 188 /* Bottom two bits of selector give the ring privilege level */
 189 #define SEGMENT_RPL_MASK        0x3
 190 /* Bit 2 is table indicator (LDT/GDT) */
 191 #define SEGMENT_TI_MASK         0x4
 192
 193 #define IDT_ENTRIES 256
 194 #define GDT_SIZE (GDT_ENTRIES * 8)
 195 #define GDT_ENTRY_TLS_ENTRIES 3
 196 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
 197
 198 #ifdef __KERNEL__
 199 #ifndef __ASSEMBLY__
 200 extern const char early_idt_handlers[IDT_ENTRIES][10];
 201 #endif
 202 #endif
 203
 204 #endif