xref: /openbmc/linux/arch/x86/include/asm/desc_defs.h (revision 9ac8d3fb)
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 */
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 enum {
38 	GATE_INTERRUPT = 0xE,
39 	GATE_TRAP = 0xF,
40 	GATE_CALL = 0xC,
41 	GATE_TASK = 0x5,
42 };
43 
44 /* 16byte gate */
45 struct gate_struct64 {
46 	u16 offset_low;
47 	u16 segment;
48 	unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
49 	u16 offset_middle;
50 	u32 offset_high;
51 	u32 zero1;
52 } __attribute__((packed));
53 
54 #define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF)
55 #define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF)
56 #define PTR_HIGH(x) ((unsigned long long)(x) >> 32)
57 
58 enum {
59 	DESC_TSS = 0x9,
60 	DESC_LDT = 0x2,
61 	DESCTYPE_S = 0x10,	/* !system */
62 };
63 
64 /* LDT or TSS descriptor in the GDT. 16 bytes. */
65 struct ldttss_desc64 {
66 	u16 limit0;
67 	u16 base0;
68 	unsigned base1 : 8, type : 5, dpl : 2, p : 1;
69 	unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
70 	u32 base3;
71 	u32 zero1;
72 } __attribute__((packed));
73 
74 #ifdef CONFIG_X86_64
75 typedef struct gate_struct64 gate_desc;
76 typedef struct ldttss_desc64 ldt_desc;
77 typedef struct ldttss_desc64 tss_desc;
78 #define gate_offset(g) ((g).offset_low | ((unsigned long)(g).offset_middle << 16) | ((unsigned long)(g).offset_high << 32))
79 #define gate_segment(g) ((g).segment)
80 #else
81 typedef struct desc_struct gate_desc;
82 typedef struct desc_struct ldt_desc;
83 typedef struct desc_struct tss_desc;
84 #define gate_offset(g)		(((g).b & 0xffff0000) | ((g).a & 0x0000ffff))
85 #define gate_segment(g)		((g).a >> 16)
86 #endif
87 
88 struct desc_ptr {
89 	unsigned short size;
90 	unsigned long address;
91 } __attribute__((packed)) ;
92 
93 #endif /* !__ASSEMBLY__ */
94 
95 #endif /* _ASM_X86_DESC_DEFS_H */
96