xref: /linux/arch/x86/include/asm/desc_defs.h (revision 6c8c1406a6d6a3f2e61ac590f5c0994231bc6be7)
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 idt_data {
78 	unsigned int	vector;
79 	unsigned int	segment;
80 	struct idt_bits	bits;
81 	const void	*addr;
82 };
83 
84 struct gate_struct {
85 	u16		offset_low;
86 	u16		segment;
87 	struct idt_bits	bits;
88 	u16		offset_middle;
89 #ifdef CONFIG_X86_64
90 	u32		offset_high;
91 	u32		reserved;
92 #endif
93 } __attribute__((packed));
94 
95 typedef struct gate_struct gate_desc;
96 
97 static inline unsigned long gate_offset(const gate_desc *g)
98 {
99 #ifdef CONFIG_X86_64
100 	return g->offset_low | ((unsigned long)g->offset_middle << 16) |
101 		((unsigned long) g->offset_high << 32);
102 #else
103 	return g->offset_low | ((unsigned long)g->offset_middle << 16);
104 #endif
105 }
106 
107 static inline unsigned long gate_segment(const gate_desc *g)
108 {
109 	return g->segment;
110 }
111 
112 struct desc_ptr {
113 	unsigned short size;
114 	unsigned long address;
115 } __attribute__((packed)) ;
116 
117 #endif /* !__ASSEMBLY__ */
118 
119 /* Boot IDT definitions */
120 #define	BOOT_IDT_ENTRIES	32
121 
122 /* Access rights as returned by LAR */
123 #define AR_TYPE_RODATA		(0 * (1 << 9))
124 #define AR_TYPE_RWDATA		(1 * (1 << 9))
125 #define AR_TYPE_RODATA_EXPDOWN	(2 * (1 << 9))
126 #define AR_TYPE_RWDATA_EXPDOWN	(3 * (1 << 9))
127 #define AR_TYPE_XOCODE		(4 * (1 << 9))
128 #define AR_TYPE_XRCODE		(5 * (1 << 9))
129 #define AR_TYPE_XOCODE_CONF	(6 * (1 << 9))
130 #define AR_TYPE_XRCODE_CONF	(7 * (1 << 9))
131 #define AR_TYPE_MASK		(7 * (1 << 9))
132 
133 #define AR_DPL0			(0 * (1 << 13))
134 #define AR_DPL3			(3 * (1 << 13))
135 #define AR_DPL_MASK		(3 * (1 << 13))
136 
137 #define AR_A			(1 << 8)   /* "Accessed" */
138 #define AR_S			(1 << 12)  /* If clear, "System" segment */
139 #define AR_P			(1 << 15)  /* "Present" */
140 #define AR_AVL			(1 << 20)  /* "AVaiLable" (no HW effect) */
141 #define AR_L			(1 << 21)  /* "Long mode" for code segments */
142 #define AR_DB			(1 << 22)  /* D/B, effect depends on type */
143 #define AR_G			(1 << 23)  /* "Granularity" (limit in pages) */
144 
145 #endif /* _ASM_X86_DESC_DEFS_H */
146