1 /* Written 2000 by Andi Kleen */
2 #ifndef __ARCH_DESC_H
3 #define __ARCH_DESC_H
4
5 #include <linux/threads.h>
6 #include <asm/ldt.h>
7
8 #ifndef __ASSEMBLY__
9
10 #define __TSS_INDEX(n) ((n)*64)
11 #define __LDT_INDEX(n) ((n)*64)
12
13 extern __u8 gdt_table[];
14 extern __u8 gdt_end[];
15
16 enum {
17 GATE_INTERRUPT = 0xE,
18 GATE_TRAP = 0xF,
19 GATE_CALL = 0xC,
20 };
21
22 // 16byte gate
23 struct gate_struct {
24 u16 offset_low;
25 u16 segment;
26 unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
27 u16 offset_middle;
28 u32 offset_high;
29 u32 zero1;
30 } __attribute__((packed));
31
32 // 8 byte segment descriptor
33 struct desc_struct {
34 u16 limit0;
35 u16 base0;
36 unsigned base1 : 8, type : 4, s : 1, dpl : 2, p : 1;
37 unsigned limit : 4, avl : 1, l : 1, d : 1, g : 1, base2 : 8;
38 } __attribute__((packed));
39
40 // LDT or TSS descriptor in the GDT. 16 bytes.
41 struct ldttss_desc {
42 u16 limit0;
43 u16 base0;
44 unsigned base1 : 8, type : 5, dpl : 2, p : 1;
45 unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
46 u32 base3;
47 u32 zero1;
48 } __attribute__((packed));
49
50
51 struct per_cpu_gdt {
52 struct ldttss_desc tss;
53 struct ldttss_desc ldt;
54 } ____cacheline_aligned;
55
56 extern struct per_cpu_gdt gdt_cpu_table[];
57
58 #define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
59 #define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
60 #define PTR_HIGH(x) ((unsigned long)(x) >> 32)
61
62 enum {
63 DESC_TSS = 0x9,
64 DESC_LDT = 0x2,
65 };
66
67 struct desc_ptr {
68 unsigned short size;
69 unsigned long address;
70 } __attribute__((packed)) ;
71
72 #define __GDT_HEAD_SIZE 64
73 #define __CPU_DESC_INDEX(x,field) \
74 ((x) * sizeof(struct per_cpu_gdt) + offsetof(struct per_cpu_gdt, field) + __GDT_HEAD_SIZE)
75
76 #define load_TR(cpu) asm volatile("ltr %w0"::"r" (__CPU_DESC_INDEX(cpu, tss)));
77 #define __load_LDT(cpu) asm volatile("lldt %w0"::"r" (__CPU_DESC_INDEX(cpu, ldt)));
78 #define clear_LDT(n) asm volatile("lldt %w0"::"r" (0))
79
80 extern struct gate_struct idt_table[];
81
82 #define copy_16byte(dst,src) memcpy((dst), (src), 16)
83
_set_gate(void * adr,unsigned type,unsigned long func,unsigned dpl,unsigned ist)84 static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
85 {
86 struct gate_struct s;
87 s.offset_low = PTR_LOW(func);
88 s.segment = __KERNEL_CS;
89 s.ist = ist;
90 s.p = 1;
91 s.dpl = dpl;
92 s.zero0 = 0;
93 s.zero1 = 0;
94 s.type = type;
95 s.offset_middle = PTR_MIDDLE(func);
96 s.offset_high = PTR_HIGH(func);
97 copy_16byte(adr, &s);
98 }
99
set_intr_gate(int nr,void * func)100 static inline void set_intr_gate(int nr, void *func)
101 {
102 _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
103 }
104
set_intr_gate_ist(int nr,void * func,unsigned ist)105 static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
106 {
107 _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
108 }
109
set_system_gate(int nr,void * func)110 static inline void set_system_gate(int nr, void *func)
111 {
112 _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
113 }
114
set_tssldt_descriptor(struct ldttss_desc * dst,unsigned long ptr,unsigned type,unsigned size)115 static inline void set_tssldt_descriptor(struct ldttss_desc *dst, unsigned long ptr, unsigned type,
116 unsigned size)
117 {
118 memset(dst,0,16);
119 dst->limit0 = size & 0xFFFF;
120 dst->base0 = PTR_LOW(ptr);
121 dst->base1 = PTR_MIDDLE(ptr) & 0xFF;
122 dst->type = type;
123 dst->p = 1;
124 dst->limit1 = (size >> 16) & 0xF;
125 dst->base2 = (PTR_MIDDLE(ptr) >> 8) & 0xFF;
126 dst->base3 = PTR_HIGH(ptr);
127 }
128
set_tss_desc(unsigned n,void * addr)129 static inline void set_tss_desc(unsigned n, void *addr)
130 {
131 set_tssldt_descriptor((void *)&gdt_table + __CPU_DESC_INDEX(n,tss), (unsigned long)addr, DESC_TSS, IO_BITMAP_OFFSET + IO_BITMAP_BYTES + 7);
132 }
133
set_ldt_desc(unsigned n,void * addr,int size)134 static inline void set_ldt_desc(unsigned n, void *addr, int size)
135 {
136 set_tssldt_descriptor((void *)&gdt_table + __CPU_DESC_INDEX(n,ldt), (unsigned long)addr, DESC_LDT, size * 8);
137 }
138
139 /*
140 * load one particular LDT into the current CPU
141 */
load_LDT(struct mm_struct * mm)142 static inline void load_LDT (struct mm_struct *mm)
143 {
144 int cpu = smp_processor_id();
145 void *segments = mm->context.segments;
146
147 if (!segments) {
148 clear_LDT(cpu);
149 return;
150 }
151
152 set_ldt_desc(cpu, segments, LDT_ENTRIES);
153 __load_LDT(cpu);
154 }
155
156 #endif /* !__ASSEMBLY__ */
157
158 #endif
159