root/arch/x86/include/asm/desc_defs.h

INCLUDED FROM

DEFINITIONS

1. gate_offset
2. gate_segment

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Written 2000 by Andi Kleen */
   3 #ifndef _ASM_X86_DESC_DEFS_H
   4 #define _ASM_X86_DESC_DEFS_H
   5 
   6 /*
   7  * Segment descriptor structure definitions, usable from both x86_64 and i386
   8  * archs.
   9  */
  10 
  11 #ifndef __ASSEMBLY__
  12 
  13 #include <linux/types.h>
  14 
  15 /* 8 byte segment descriptor */
  16 struct desc_struct {
  17         u16     limit0;
  18         u16     base0;
  19         u16     base1: 8, type: 4, s: 1, dpl: 2, p: 1;
  20         u16     limit1: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
  21 } __attribute__((packed));
  22 
  23 #define GDT_ENTRY_INIT(flags, base, limit)                      \
  24         {                                                       \
  25                 .limit0         = (u16) (limit),                \
  26                 .limit1         = ((limit) >> 16) & 0x0F,       \
  27                 .base0          = (u16) (base),                 \
  28                 .base1          = ((base) >> 16) & 0xFF,        \
  29                 .base2          = ((base) >> 24) & 0xFF,        \
  30                 .type           = (flags & 0x0f),               \
  31                 .s              = (flags >> 4) & 0x01,          \
  32                 .dpl            = (flags >> 5) & 0x03,          \
  33                 .p              = (flags >> 7) & 0x01,          \
  34                 .avl            = (flags >> 12) & 0x01,         \
  35                 .l              = (flags >> 13) & 0x01,         \
  36                 .d              = (flags >> 14) & 0x01,         \
  37                 .g              = (flags >> 15) & 0x01,         \
  38         }
  39 
  40 enum {
  41         GATE_INTERRUPT = 0xE,
  42         GATE_TRAP = 0xF,
  43         GATE_CALL = 0xC,
  44         GATE_TASK = 0x5,
  45 };
  46 
  47 enum {
  48         DESC_TSS = 0x9,
  49         DESC_LDT = 0x2,
  50         DESCTYPE_S = 0x10,      /* !system */
  51 };
  52 
  53 /* LDT or TSS descriptor in the GDT. */
  54 struct ldttss_desc {
  55         u16     limit0;
  56         u16     base0;
  57 
  58         u16     base1 : 8, type : 5, dpl : 2, p : 1;
  59         u16     limit1 : 4, zero0 : 3, g : 1, base2 : 8;
  60 #ifdef CONFIG_X86_64
  61         u32     base3;
  62         u32     zero1;
  63 #endif
  64 } __attribute__((packed));
  65 
  66 typedef struct ldttss_desc ldt_desc;
  67 typedef struct ldttss_desc tss_desc;
  68 
  69 struct idt_bits {
  70         u16             ist     : 3,
  71                         zero    : 5,
  72                         type    : 5,
  73                         dpl     : 2,
  74                         p       : 1;
  75 } __attribute__((packed));
  76 
  77 struct gate_struct {
  78         u16             offset_low;
  79         u16             segment;
  80         struct idt_bits bits;
  81         u16             offset_middle;
  82 #ifdef CONFIG_X86_64
  83         u32             offset_high;
  84         u32             reserved;
  85 #endif
  86 } __attribute__((packed));
  87 
  88 typedef struct gate_struct gate_desc;
  89 
  90 static inline unsigned long gate_offset(const gate_desc *g)
  91 {
  92 #ifdef CONFIG_X86_64
  93         return g->offset_low | ((unsigned long)g->offset_middle << 16) |
  94                 ((unsigned long) g->offset_high << 32);
  95 #else
  96         return g->offset_low | ((unsigned long)g->offset_middle << 16);
  97 #endif
  98 }
  99 
 100 static inline unsigned long gate_segment(const gate_desc *g)
 101 {
 102         return g->segment;
 103 }
 104 
 105 struct desc_ptr {
 106         unsigned short size;
 107         unsigned long address;
 108 } __attribute__((packed)) ;
 109 
 110 #endif /* !__ASSEMBLY__ */
 111 
 112 /* Access rights as returned by LAR */
 113 #define AR_TYPE_RODATA          (0 * (1 << 9))
 114 #define AR_TYPE_RWDATA          (1 * (1 << 9))
 115 #define AR_TYPE_RODATA_EXPDOWN  (2 * (1 << 9))
 116 #define AR_TYPE_RWDATA_EXPDOWN  (3 * (1 << 9))
 117 #define AR_TYPE_XOCODE          (4 * (1 << 9))
 118 #define AR_TYPE_XRCODE          (5 * (1 << 9))
 119 #define AR_TYPE_XOCODE_CONF     (6 * (1 << 9))
 120 #define AR_TYPE_XRCODE_CONF     (7 * (1 << 9))
 121 #define AR_TYPE_MASK            (7 * (1 << 9))
 122 
 123 #define AR_DPL0                 (0 * (1 << 13))
 124 #define AR_DPL3                 (3 * (1 << 13))
 125 #define AR_DPL_MASK             (3 * (1 << 13))
 126 
 127 #define AR_A                    (1 << 8)   /* "Accessed" */
 128 #define AR_S                    (1 << 12)  /* If clear, "System" segment */
 129 #define AR_P                    (1 << 15)  /* "Present" */
 130 #define AR_AVL                  (1 << 20)  /* "AVaiLable" (no HW effect) */
 131 #define AR_L                    (1 << 21)  /* "Long mode" for code segments */
 132 #define AR_DB                   (1 << 22)  /* D/B, effect depends on type */
 133 #define AR_G                    (1 << 23)  /* "Granularity" (limit in pages) */
 134 
 135 #endif /* _ASM_X86_DESC_DEFS_H */