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 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