LXR linux/include/asm-x86/desc

   1/* Written 2000 by Andi Kleen */
   2#ifndef __ARCH_DESC_DEFS_H
   3#define __ARCH_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: Acessing 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 acessors, and doing this allow us to do it
  18 * incrementally. We keep the signature as a struct, rather than an union,
  19 * so we can get rid of it transparently in the future -- glommer
  20 */
  21// 8 byte segment descriptor
  22struct desc_struct {
  23        union {
  24                struct { unsigned int a, b; };
  25                struct {
  26                        u16 limit0;
  27                        u16 base0;
  28                        unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1;
  29                        unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
  30                };
  31
  32        };
  33} __attribute__((packed));
  34
  35enum {
  36        GATE_INTERRUPT = 0xE,
  37        GATE_TRAP = 0xF,
  38        GATE_CALL = 0xC,
  39        GATE_TASK = 0x5,
  40};
  41
  42// 16byte gate
  43struct gate_struct64 {
  44        u16 offset_low;
  45        u16 segment;
  46        unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
  47        u16 offset_middle;
  48        u32 offset_high;
  49        u32 zero1;
  50} __attribute__((packed));
  51
  52#define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF)
  53#define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF)
  54#define PTR_HIGH(x) ((unsigned long long)(x) >> 32)
  55
  56enum {
  57        DESC_TSS = 0x9,
  58        DESC_LDT = 0x2,
  59        DESCTYPE_S =    0x10,   /* !system */
  60};
  61
  62// LDT or TSS descriptor in the GDT. 16 bytes.
  63struct ldttss_desc64 {
  64        u16 limit0;
  65        u16 base0;
  66        unsigned base1 : 8, type : 5, dpl : 2, p : 1;
  67        unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
  68        u32 base3;
  69        u32 zero1;
  70} __attribute__((packed));
  71
  72#ifdef CONFIG_X86_64
  73typedef struct gate_struct64 gate_desc;
  74typedef struct ldttss_desc64 ldt_desc;
  75typedef struct ldttss_desc64 tss_desc;
  76#else
  77typedef struct desc_struct gate_desc;
  78typedef struct desc_struct ldt_desc;
  79typedef struct desc_struct tss_desc;
  80#endif
  81
  82struct desc_ptr {
  83        unsigned short size;
  84        unsigned long address;
  85} __attribute__((packed)) ;
  86
  87
  88#endif /* !__ASSEMBLY__ */
  89
  90#endif
  91