arch/x86/include/asm/desc_defs.h

   1 /* Written 2000 by Andi Kleen */
   2 #ifndef _ASM_X86_DESC_DEFS_H
   3 #define _ASM_X86_DESC_DEFS_H
   4
   5 /*
   6  * Segment descriptor structure definitions, usable from both x86_64 and i386
   7  * archs.
   8  */
   9
  10 #ifndef __ASSEMBLY__
  11
  12 #include <linux/types.h>
  13
  14 /*
  15  * FIXME: Accessing the desc_struct through its fields is more elegant,
  16  * and should be the one valid thing to do. However, a lot of open code
  17  * still touches the a and b accessors, and doing this allow us to do it
  18  * incrementally. We keep the signature as a struct, rather than a union,
  19  * so we can get rid of it transparently in the future -- glommer
  20  */
  21 /* 8 byte segment descriptor */
  22 struct desc_struct {
  23         union {
  24                 struct {
  25                         unsigned int a;
  26                         unsigned int b;
  27                 };
  28                 struct {
  29                         u16 limit0;
  30                         u16 base0;
  31                         unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1;
  32                         unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
  33                 };
  34         };
  35 } __attribute__((packed));
  36
  37 #define GDT_ENTRY_INIT(flags, base, limit) { { { \
  38                 .a = ((limit) & 0xffff) | (((base) & 0xffff) << 16), \
  39                 .b = (((base) & 0xff0000) >> 16) | (((flags) & 0xf0ff) << 8) | \
  40                         ((limit) & 0xf0000) | ((base) & 0xff000000), \
  41         } } }
  42
  43 enum {
  44         GATE_INTERRUPT = 0xE,
  45         GATE_TRAP = 0xF,
  46         GATE_CALL = 0xC,
  47         GATE_TASK = 0x5,
  48 };
  49
  50 enum {
  51         DESC_TSS = 0x9,
  52         DESC_LDT = 0x2,
  53         DESCTYPE_S = 0x10,      /* !system */
  54 };
  55
  56 /* LDT or TSS descriptor in the GDT. 16 bytes. */
  57 struct ldttss_desc64 {
  58         u16 limit0;
  59         u16 base0;
  60         unsigned base1 : 8, type : 5, dpl : 2, p : 1;
  61         unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
  62         u32 base3;
  63         u32 zero1;
  64 } __attribute__((packed));
  65
  66
  67 #ifdef CONFIG_X86_64
  68 typedef struct ldttss_desc64 ldt_desc;
  69 typedef struct ldttss_desc64 tss_desc;
  70 #else
  71 typedef struct desc_struct ldt_desc;
  72 typedef struct desc_struct tss_desc;
  73 #endif
  74
  75 struct idt_bits {
  76         u16             ist     : 3,
  77                         zero    : 5,
  78                         type    : 5,
  79                         dpl     : 2,
  80                         p       : 1;
  81 } __attribute__((packed));
  82
  83 struct gate_struct {
  84         u16             offset_low;
  85         u16             segment;
  86         struct idt_bits bits;
  87         u16             offset_middle;
  88 #ifdef CONFIG_X86_64
  89         u32             offset_high;
  90         u32             reserved;
  91 #endif
  92 } __attribute__((packed));
  93
  94 typedef struct gate_struct gate_desc;
  95
  96 static inline unsigned long gate_offset(const gate_desc *g)
  97 {
  98 #ifdef CONFIG_X86_64
  99         return g->offset_low | ((unsigned long)g->offset_middle << 16) |
 100                 ((unsigned long) g->offset_high << 32);
 101 #else
 102         return g->offset_low | ((unsigned long)g->offset_middle << 16);
 103 #endif
 104 }
 105
 106 static inline unsigned long gate_segment(const gate_desc *g)
 107 {
 108         return g->segment;
 109 }
 110
 111 struct desc_ptr {
 112         unsigned short size;
 113         unsigned long address;
 114 } __attribute__((packed)) ;
 115
 116 #endif /* !__ASSEMBLY__ */
 117
 118 /* Access rights as returned by LAR */
 119 #define AR_TYPE_RODATA          (0 * (1 << 9))
 120 #define AR_TYPE_RWDATA          (1 * (1 << 9))
 121 #define AR_TYPE_RODATA_EXPDOWN  (2 * (1 << 9))
 122 #define AR_TYPE_RWDATA_EXPDOWN  (3 * (1 << 9))
 123 #define AR_TYPE_XOCODE          (4 * (1 << 9))
 124 #define AR_TYPE_XRCODE          (5 * (1 << 9))
 125 #define AR_TYPE_XOCODE_CONF     (6 * (1 << 9))
 126 #define AR_TYPE_XRCODE_CONF     (7 * (1 << 9))
 127 #define AR_TYPE_MASK            (7 * (1 << 9))
 128
 129 #define AR_DPL0                 (0 * (1 << 13))
 130 #define AR_DPL3                 (3 * (1 << 13))
 131 #define AR_DPL_MASK             (3 * (1 << 13))
 132
 133 #define AR_A                    (1 << 8)   /* "Accessed" */
 134 #define AR_S                    (1 << 12)  /* If clear, "System" segment */
 135 #define AR_P                    (1 << 15)  /* "Present" */
 136 #define AR_AVL                  (1 << 20)  /* "AVaiLable" (no HW effect) */
 137 #define AR_L                    (1 << 21)  /* "Long mode" for code segments */
 138 #define AR_DB                   (1 << 22)  /* D/B, effect depends on type */
 139 #define AR_G                    (1 << 23)  /* "Granularity" (limit in pages) */
 140
 141 #endif /* _ASM_X86_DESC_DEFS_H */