1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
/* Written 2000 by Andi Kleen */
#ifndef __ARCH_DESC_H
#define __ARCH_DESC_H
#include <linux/threads.h>
#include <asm/ldt.h>
#ifndef __ASSEMBLY__
#include <linux/string.h>
#include <linux/smp.h>
#include <asm/segment.h>
#include <asm/mmu.h>
// 8 byte segment descriptor
struct desc_struct {
u16 limit0;
u16 base0;
unsigned base1 : 8, type : 4, s : 1, dpl : 2, p : 1;
unsigned limit : 4, avl : 1, l : 1, d : 1, g : 1, base2 : 8;
} __attribute__((packed));
struct n_desc_struct {
unsigned int a,b;
};
extern struct desc_struct cpu_gdt_table[NR_CPUS][GDT_ENTRIES];
enum {
GATE_INTERRUPT = 0xE,
GATE_TRAP = 0xF,
GATE_CALL = 0xC,
};
// 16byte gate
struct gate_struct {
u16 offset_low;
u16 segment;
unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
u16 offset_middle;
u32 offset_high;
u32 zero1;
} __attribute__((packed));
#define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
#define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
#define PTR_HIGH(x) ((unsigned long)(x) >> 32)
enum {
DESC_TSS = 0x9,
DESC_LDT = 0x2,
};
// LDT or TSS descriptor in the GDT. 16 bytes.
struct ldttss_desc {
u16 limit0;
u16 base0;
unsigned base1 : 8, type : 5, dpl : 2, p : 1;
unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
u32 base3;
u32 zero1;
} __attribute__((packed));
struct desc_ptr {
unsigned short size;
unsigned long address;
} __attribute__((packed)) ;
#define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
#define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
#define clear_LDT() asm volatile("lldt %w0"::"r" (0))
/*
* This is the ldt that every process will get unless we need
* something other than this.
*/
extern struct desc_struct default_ldt[];
extern struct gate_struct idt_table[];
extern struct desc_ptr cpu_gdt_descr[];
static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
{
struct gate_struct s;
s.offset_low = PTR_LOW(func);
s.segment = __KERNEL_CS;
s.ist = ist;
s.p = 1;
s.dpl = dpl;
s.zero0 = 0;
s.zero1 = 0;
s.type = type;
s.offset_middle = PTR_MIDDLE(func);
s.offset_high = PTR_HIGH(func);
/* does not need to be atomic because it is only done once at setup time */
memcpy(adr, &s, 16);
}
static inline void set_intr_gate(int nr, void *func)
{
BUG_ON((unsigned)nr > 0xFF);
_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
}
static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
{
BUG_ON((unsigned)nr > 0xFF);
_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
}
static inline void set_system_gate(int nr, void *func)
{
BUG_ON((unsigned)nr > 0xFF);
_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
}
static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type,
unsigned size)
{
struct ldttss_desc d;
memset(&d,0,sizeof(d));
d.limit0 = size & 0xFFFF;
d.base0 = PTR_LOW(tss);
d.base1 = PTR_MIDDLE(tss) & 0xFF;
d.type = type;
d.p = 1;
d.limit1 = (size >> 16) & 0xF;
d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
d.base3 = PTR_HIGH(tss);
memcpy(ptr, &d, 16);
}
static inline void set_tss_desc(unsigned cpu, void *addr)
{
/*
* sizeof(unsigned long) coming from an extra "long" at the end
* of the iobitmap. See tss_struct definition in processor.h
*
* -1? seg base+limit should be pointing to the address of the
* last valid byte
*/
set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_TSS],
(unsigned long)addr, DESC_TSS,
IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1);
}
static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
{
set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_LDT], (unsigned long)addr,
DESC_LDT, size * 8 - 1);
}
static inline void set_seg_base(unsigned cpu, int entry, void *base)
{
struct desc_struct *d = &cpu_gdt_table[cpu][entry];
u32 addr = (u32)(u64)base;
BUG_ON((u64)base >> 32);
d->base0 = addr & 0xffff;
d->base1 = (addr >> 16) & 0xff;
d->base2 = (addr >> 24) & 0xff;
}
#define LDT_entry_a(info) \
((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
/* Don't allow setting of the lm bit. It is useless anyways because
64bit system calls require __USER_CS. */
#define LDT_entry_b(info) \
(((info)->base_addr & 0xff000000) | \
(((info)->base_addr & 0x00ff0000) >> 16) | \
((info)->limit & 0xf0000) | \
(((info)->read_exec_only ^ 1) << 9) | \
((info)->contents << 10) | \
(((info)->seg_not_present ^ 1) << 15) | \
((info)->seg_32bit << 22) | \
((info)->limit_in_pages << 23) | \
((info)->useable << 20) | \
/* ((info)->lm << 21) | */ \
0x7000)
#define LDT_empty(info) (\
(info)->base_addr == 0 && \
(info)->limit == 0 && \
(info)->contents == 0 && \
(info)->read_exec_only == 1 && \
(info)->seg_32bit == 0 && \
(info)->limit_in_pages == 0 && \
(info)->seg_not_present == 1 && \
(info)->useable == 0 && \
(info)->lm == 0)
#if TLS_SIZE != 24
# error update this code.
#endif
static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
{
u64 *gdt = (u64 *)(cpu_gdt_table[cpu] + GDT_ENTRY_TLS_MIN);
gdt[0] = t->tls_array[0];
gdt[1] = t->tls_array[1];
gdt[2] = t->tls_array[2];
}
/*
* load one particular LDT into the current CPU
*/
static inline void load_LDT_nolock (mm_context_t *pc, int cpu)
{
int count = pc->size;
if (likely(!count)) {
clear_LDT();
return;
}
set_ldt_desc(cpu, pc->ldt, count);
load_LDT_desc();
}
static inline void load_LDT(mm_context_t *pc)
{
int cpu = get_cpu();
load_LDT_nolock(pc, cpu);
put_cpu();
}
extern struct desc_ptr idt_descr;
#endif /* !__ASSEMBLY__ */
#endif
|
