LXR linux/arch/x86/include/asm/desc

   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: 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 {
  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
  43enum {
  44        GATE_INTERRUPT = 0xE,
  45        GATE_TRAP = 0xF,
  46        GATE_CALL = 0xC,
  47        GATE_TASK = 0x5,
  48};
  49
  50/* 16byte gate */
  51struct gate_struct64 {
  52        u16 offset_low;
  53        u16 segment;
  54        unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
  55        u16 offset_middle;
  56        u32 offset_high;
  57        u32 zero1;
  58} __attribute__((packed));
  59
  60#define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF)
  61#define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF)
  62#define PTR_HIGH(x) ((unsigned long long)(x) >> 32)
  63
  64enum {
  65        DESC_TSS = 0x9,
  66        DESC_LDT = 0x2,
  67        DESCTYPE_S = 0x10,      /* !system */
  68};
  69
  70/* LDT or TSS descriptor in the GDT. 16 bytes. */
  71struct ldttss_desc64 {
  72        u16 limit0;
  73        u16 base0;
  74        unsigned base1 : 8, type : 5, dpl : 2, p : 1;
  75        unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
  76        u32 base3;
  77        u32 zero1;
  78} __attribute__((packed));
  79
  80#ifdef CONFIG_X86_64
  81typedef struct gate_struct64 gate_desc;
  82typedef struct ldttss_desc64 ldt_desc;
  83typedef struct ldttss_desc64 tss_desc;
  84#define gate_offset(g) ((g).offset_low | ((unsigned long)(g).offset_middle << 16) | ((unsigned long)(g).offset_high << 32))
  85#define gate_segment(g) ((g).segment)
  86#else
  87typedef struct desc_struct gate_desc;
  88typedef struct desc_struct ldt_desc;
  89typedef struct desc_struct tss_desc;
  90#define gate_offset(g)          (((g).b & 0xffff0000) | ((g).a & 0x0000ffff))
  91#define gate_segment(g)         ((g).a >> 16)
  92#endif
  93
  94struct desc_ptr {
  95        unsigned short size;
  96        unsigned long address;
  97} __attribute__((packed)) ;
  98
  99#endif /* !__ASSEMBLY__ */
 100
 101#endif /* _ASM_X86_DESC_DEFS_H */
 102