aboutsummaryrefslogtreecommitdiff
path: root/include/asm-x86/desc_32.h
blob: 41d8214c6173878d9e1aa350eb926c971c9fa726 (plain)
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
231
232
233
234
235
236
237
238
239
240
#ifndef __ARCH_DESC_H
#define __ARCH_DESC_H

#include <asm/ldt.h>
#include <asm/segment.h>
#include <asm/desc_defs.h>

#ifndef __ASSEMBLY__

#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/percpu.h>

#include <asm/mmu.h>

struct gdt_page
{
	struct desc_struct gdt[GDT_ENTRIES];
} __attribute__((aligned(PAGE_SIZE)));
DECLARE_PER_CPU(struct gdt_page, gdt_page);

static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
{
	return per_cpu(gdt_page, cpu).gdt;
}

extern struct desc_ptr idt_descr;
extern gate_desc idt_table[];
extern void set_intr_gate(unsigned int irq, void * addr);

static inline void pack_descriptor(struct desc_struct *desc,
	unsigned long base, unsigned long limit, unsigned char type, unsigned char flags)
{
	desc->a = ((base & 0xffff) << 16) | (limit & 0xffff);
	desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
		(limit & 0x000f0000) | ((type & 0xff) << 8) | ((flags & 0xf) << 20);
	desc->p = 1;
}

static inline void pack_gate(gate_desc *gate,
	unsigned long base, unsigned short seg, unsigned char type, unsigned char flags)
{
	gate->a = (seg << 16) | (base & 0xffff);
	gate->b = (base & 0xffff0000) | ((type & 0xff) << 8) | (flags & 0xff);
}

#define DESCTYPE_LDT 	0x82	/* present, system, DPL-0, LDT */
#define DESCTYPE_TSS 	0x89	/* present, system, DPL-0, 32-bit TSS */
#define DESCTYPE_TASK	0x85	/* present, system, DPL-0, task gate */
#define DESCTYPE_INT	0x8e	/* present, system, DPL-0, interrupt gate */
#define DESCTYPE_TRAP	0x8f	/* present, system, DPL-0, trap gate */
#define DESCTYPE_DPL3	0x60	/* DPL-3 */
#define DESCTYPE_S	0x10	/* !system */

#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#define load_TR_desc() native_load_tr_desc()
#define load_gdt(dtr) native_load_gdt(dtr)
#define load_idt(dtr) native_load_idt(dtr)
#define load_tr(tr) __asm__ __volatile("ltr %0"::"m" (tr))
#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"m" (ldt))

#define store_gdt(dtr) native_store_gdt(dtr)
#define store_idt(dtr) native_store_idt(dtr)
#define store_tr(tr) (tr = native_store_tr())
#define store_ldt(ldt) __asm__ ("sldt %0":"=m" (ldt))

#define load_TLS(t, cpu) native_load_tls(t, cpu)
#define set_ldt native_set_ldt

#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_gdt_entry(dt, entry, desc, type) \
				native_write_gdt_entry(dt, entry, desc, type)
#define write_idt_entry(dt, entry, g) native_write_idt_entry(dt, entry, g)
#endif

static inline void native_write_idt_entry(gate_desc *idt, int entry,
					  const gate_desc *gate)
{
	memcpy(&idt[entry], gate, sizeof(*gate));
}

static inline void native_write_gdt_entry(struct desc_struct *gdt, int entry,
					  const void *desc, int type)
{
	memcpy(&gdt[entry], desc, sizeof(struct desc_struct));
}

static inline void write_dt_entry(struct desc_struct *dt,
				  int entry, u32 entry_low, u32 entry_high)
{
	dt[entry].a = entry_low;
	dt[entry].b = entry_high;
}


static inline void native_set_ldt(const void *addr, unsigned int entries)
{
	if (likely(entries == 0))
		__asm__ __volatile__("lldt %w0"::"q" (0));
	else {
		unsigned cpu = smp_processor_id();
		ldt_desc ldt;

		pack_descriptor(&ldt, (unsigned long)addr,
				entries * sizeof(struct desc_struct) - 1,
				DESC_LDT, 0);
		write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
				&ldt, DESC_LDT);
		__asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
	}
}


static inline void native_load_tr_desc(void)
{
	asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
}

static inline void native_load_gdt(const struct desc_ptr *dtr)
{
	asm volatile("lgdt %0"::"m" (*dtr));
}

static inline void native_load_idt(const struct desc_ptr *dtr)
{
	asm volatile("lidt %0"::"m" (*dtr));
}

static inline void native_store_gdt(struct desc_ptr *dtr)
{
	asm ("sgdt %0":"=m" (*dtr));
}

static inline void native_store_idt(struct desc_ptr *dtr)
{
	asm ("sidt %0":"=m" (*dtr));
}

static inline unsigned long native_store_tr(void)
{
	unsigned long tr;
	asm ("str %0":"=r" (tr));
	return tr;
}

static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
{
	unsigned int i;
	struct desc_struct *gdt = get_cpu_gdt_table(cpu);

	for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
		gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
}

static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
{
	gate_desc g;
	pack_gate(&g, (unsigned long)addr, seg, type, 0);
	write_idt_entry(idt_table, gate, &g);
}

static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
{
	tss_desc tss;
	pack_descriptor(&tss, (unsigned long)addr,
			offsetof(struct tss_struct, __cacheline_filler) - 1,
			DESC_TSS, 0);
	write_gdt_entry(get_cpu_gdt_table(cpu), entry, &tss, DESC_TSS);
}


#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)

#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	)

static inline void clear_LDT(void)
{
	set_ldt(NULL, 0);
}

/*
 * load one particular LDT into the current CPU
 */
static inline void load_LDT_nolock(mm_context_t *pc)
{
	set_ldt(pc->ldt, pc->size);
}

static inline void load_LDT(mm_context_t *pc)
{
	preempt_disable();
	load_LDT_nolock(pc);
	preempt_enable();
}

static inline unsigned long get_desc_base(unsigned long *desc)
{
	unsigned long base;
	base = ((desc[0] >> 16)  & 0x0000ffff) |
		((desc[1] << 16) & 0x00ff0000) |
		(desc[1] & 0xff000000);
	return base;
}

#else /* __ASSEMBLY__ */

/*
 * GET_DESC_BASE reads the descriptor base of the specified segment.
 *
 * Args:
 *    idx - descriptor index
 *    gdt - GDT pointer
 *    base - 32bit register to which the base will be written
 *    lo_w - lo word of the "base" register
 *    lo_b - lo byte of the "base" register
 *    hi_b - hi byte of the low word of the "base" register
 *
 * Example:
 *    GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
 *    Will read the base address of GDT_ENTRY_ESPFIX_SS and put it into %eax.
 */
#define GET_DESC_BASE(idx, gdt, base, lo_w, lo_b, hi_b) \
	movb idx*8+4(gdt), lo_b; \
	movb idx*8+7(gdt), hi_b; \
	shll $16, base; \
	movw idx*8+2(gdt), lo_w;

#endif /* !__ASSEMBLY__ */

#endif