summaryrefslogtreecommitdiff
path: root/arch/i386/kernel/paravirt.c
blob: 79c167fcaee9d97558c173bde5647bdd83445ebb (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
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
/*  Paravirtualization interfaces
    Copyright (C) 2006 Rusty Russell IBM Corporation

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/bcd.h>
#include <linux/highmem.h>

#include <asm/bug.h>
#include <asm/paravirt.h>
#include <asm/desc.h>
#include <asm/setup.h>
#include <asm/arch_hooks.h>
#include <asm/time.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/fixmap.h>
#include <asm/apic.h>
#include <asm/tlbflush.h>
#include <asm/timer.h>

/* nop stub */
void _paravirt_nop(void)
{
}

static void __init default_banner(void)
{
	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
	       paravirt_ops.name);
}

char *memory_setup(void)
{
	return paravirt_ops.memory_setup();
}

/* Simple instruction patching code. */
#define DEF_NATIVE(name, code)					\
	extern const char start_##name[], end_##name[];		\
	asm("start_" #name ": " code "; end_" #name ":")

DEF_NATIVE(irq_disable, "cli");
DEF_NATIVE(irq_enable, "sti");
DEF_NATIVE(restore_fl, "push %eax; popf");
DEF_NATIVE(save_fl, "pushf; pop %eax");
DEF_NATIVE(iret, "iret");
DEF_NATIVE(irq_enable_sysexit, "sti; sysexit");
DEF_NATIVE(read_cr2, "mov %cr2, %eax");
DEF_NATIVE(write_cr3, "mov %eax, %cr3");
DEF_NATIVE(read_cr3, "mov %cr3, %eax");
DEF_NATIVE(clts, "clts");
DEF_NATIVE(read_tsc, "rdtsc");

DEF_NATIVE(ud2a, "ud2a");

static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len)
{
	const unsigned char *start, *end;
	unsigned ret;

	switch(type) {
#define SITE(x)	case PARAVIRT_PATCH(x):	start = start_##x; end = end_##x; goto patch_site
		SITE(irq_disable);
		SITE(irq_enable);
		SITE(restore_fl);
		SITE(save_fl);
		SITE(iret);
		SITE(irq_enable_sysexit);
		SITE(read_cr2);
		SITE(read_cr3);
		SITE(write_cr3);
		SITE(clts);
		SITE(read_tsc);
#undef SITE

	patch_site:
		ret = paravirt_patch_insns(insns, len, start, end);
		break;

	case PARAVIRT_PATCH(make_pgd):
	case PARAVIRT_PATCH(make_pte):
	case PARAVIRT_PATCH(pgd_val):
	case PARAVIRT_PATCH(pte_val):
#ifdef CONFIG_X86_PAE
	case PARAVIRT_PATCH(make_pmd):
	case PARAVIRT_PATCH(pmd_val):
#endif
		/* These functions end up returning exactly what
		   they're passed, in the same registers. */
		ret = paravirt_patch_nop();
		break;

	default:
		ret = paravirt_patch_default(type, clobbers, insns, len);
		break;
	}

	return ret;
}

unsigned paravirt_patch_nop(void)
{
	return 0;
}

unsigned paravirt_patch_ignore(unsigned len)
{
	return len;
}

struct branch {
	unsigned char opcode;
	u32 delta;
} __attribute__((packed));

unsigned paravirt_patch_call(void *target, u16 tgt_clobbers,
			     void *site, u16 site_clobbers,
			     unsigned len)
{
	unsigned char *call = site;
	unsigned long delta = (unsigned long)target - (unsigned long)(call+5);
	struct branch b;

	if (tgt_clobbers & ~site_clobbers)
		return len;	/* target would clobber too much for this site */
	if (len < 5)
		return len;	/* call too long for patch site */

	b.opcode = 0xe8; /* call */
	b.delta = delta;
	BUILD_BUG_ON(sizeof(b) != 5);
	text_poke(call, (unsigned char *)&b, 5);

	return 5;
}

unsigned paravirt_patch_jmp(void *target, void *site, unsigned len)
{
	unsigned char *jmp = site;
	unsigned long delta = (unsigned long)target - (unsigned long)(jmp+5);

	if (len < 5)
		return len;	/* call too long for patch site */

	b.opcode = 0xe9;	/* jmp */
	b.delta = delta;
	text_poke(call, (unsigned char *)&b, 5);

	return 5;
}

unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len)
{
	void *opfunc = *((void **)&paravirt_ops + type);
	unsigned ret;

	if (opfunc == NULL)
		/* If there's no function, patch it with a ud2a (BUG) */
		ret = paravirt_patch_insns(site, len, start_ud2a, end_ud2a);
	else if (opfunc == paravirt_nop)
		/* If the operation is a nop, then nop the callsite */
		ret = paravirt_patch_nop();
	else if (type == PARAVIRT_PATCH(iret) ||
		 type == PARAVIRT_PATCH(irq_enable_sysexit))
		/* If operation requires a jmp, then jmp */
		ret = paravirt_patch_jmp(opfunc, site, len);
	else
		/* Otherwise call the function; assume target could
		   clobber any caller-save reg */
		ret = paravirt_patch_call(opfunc, CLBR_ANY,
					  site, clobbers, len);

	return ret;
}

unsigned paravirt_patch_insns(void *site, unsigned len,
			      const char *start, const char *end)
{
	unsigned insn_len = end - start;

	if (insn_len > len || start == NULL)
		insn_len = len;
	else
		memcpy(site, start, insn_len);

	return insn_len;
}

void init_IRQ(void)
{
	paravirt_ops.init_IRQ();
}

static void native_flush_tlb(void)
{
	__native_flush_tlb();
}

/*
 * Global pages have to be flushed a bit differently. Not a real
 * performance problem because this does not happen often.
 */
static void native_flush_tlb_global(void)
{
	__native_flush_tlb_global();
}

static void native_flush_tlb_single(unsigned long addr)
{
	__native_flush_tlb_single(addr);
}

/* These are in entry.S */
extern void native_iret(void);
extern void native_irq_enable_sysexit(void);

static int __init print_banner(void)
{
	paravirt_ops.banner();
	return 0;
}
core_initcall(print_banner);

static struct resource reserve_ioports = {
	.start = 0,
	.end = IO_SPACE_LIMIT,
	.name = "paravirt-ioport",
	.flags = IORESOURCE_IO | IORESOURCE_BUSY,
};

static struct resource reserve_iomem = {
	.start = 0,
	.end = -1,
	.name = "paravirt-iomem",
	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
};

/*
 * Reserve the whole legacy IO space to prevent any legacy drivers
 * from wasting time probing for their hardware.  This is a fairly
 * brute-force approach to disabling all non-virtual drivers.
 *
 * Note that this must be called very early to have any effect.
 */
int paravirt_disable_iospace(void)
{
	int ret;

	ret = request_resource(&ioport_resource, &reserve_ioports);
	if (ret == 0) {
		ret = request_resource(&iomem_resource, &reserve_iomem);
		if (ret)
			release_resource(&reserve_ioports);
	}

	return ret;
}

struct paravirt_ops paravirt_ops = {
	.name = "bare hardware",
	.paravirt_enabled = 0,
	.kernel_rpl = 0,
	.shared_kernel_pmd = 1,	/* Only used when CONFIG_X86_PAE is set */

 	.patch = native_patch,
	.banner = default_banner,
	.arch_setup = paravirt_nop,
	.memory_setup = machine_specific_memory_setup,
	.get_wallclock = native_get_wallclock,
	.set_wallclock = native_set_wallclock,
	.time_init = hpet_time_init,
	.init_IRQ = native_init_IRQ,

	.cpuid = native_cpuid,
	.get_debugreg = native_get_debugreg,
	.set_debugreg = native_set_debugreg,
	.clts = native_clts,
	.read_cr0 = native_read_cr0,
	.write_cr0 = native_write_cr0,
	.read_cr2 = native_read_cr2,
	.write_cr2 = native_write_cr2,
	.read_cr3 = native_read_cr3,
	.write_cr3 = native_write_cr3,
	.read_cr4 = native_read_cr4,
	.read_cr4_safe = native_read_cr4_safe,
	.write_cr4 = native_write_cr4,
	.save_fl = native_save_fl,
	.restore_fl = native_restore_fl,
	.irq_disable = native_irq_disable,
	.irq_enable = native_irq_enable,
	.safe_halt = native_safe_halt,
	.halt = native_halt,
	.wbinvd = native_wbinvd,
	.read_msr = native_read_msr_safe,
	.write_msr = native_write_msr_safe,
	.read_tsc = native_read_tsc,
	.read_pmc = native_read_pmc,
	.sched_clock = native_sched_clock,
	.get_cpu_khz = native_calculate_cpu_khz,
	.load_tr_desc = native_load_tr_desc,
	.set_ldt = native_set_ldt,
	.load_gdt = native_load_gdt,
	.load_idt = native_load_idt,
	.store_gdt = native_store_gdt,
	.store_idt = native_store_idt,
	.store_tr = native_store_tr,
	.load_tls = native_load_tls,
	.write_ldt_entry = write_dt_entry,
	.write_gdt_entry = write_dt_entry,
	.write_idt_entry = write_dt_entry,
	.load_esp0 = native_load_esp0,

	.set_iopl_mask = native_set_iopl_mask,
	.io_delay = native_io_delay,

#ifdef CONFIG_X86_LOCAL_APIC
	.apic_write = native_apic_write,
	.apic_write_atomic = native_apic_write_atomic,
	.apic_read = native_apic_read,
	.setup_boot_clock = setup_boot_APIC_clock,
	.setup_secondary_clock = setup_secondary_APIC_clock,
	.startup_ipi_hook = paravirt_nop,
#endif
	.set_lazy_mode = paravirt_nop,

	.pagetable_setup_start = native_pagetable_setup_start,
	.pagetable_setup_done = native_pagetable_setup_done,

	.flush_tlb_user = native_flush_tlb,
	.flush_tlb_kernel = native_flush_tlb_global,
	.flush_tlb_single = native_flush_tlb_single,
	.flush_tlb_others = native_flush_tlb_others,

	.alloc_pt = paravirt_nop,
	.alloc_pd = paravirt_nop,
	.alloc_pd_clone = paravirt_nop,
	.release_pt = paravirt_nop,
	.release_pd = paravirt_nop,

	.set_pte = native_set_pte,
	.set_pte_at = native_set_pte_at,
	.set_pmd = native_set_pmd,
	.pte_update = paravirt_nop,
	.pte_update_defer = paravirt_nop,

#ifdef CONFIG_HIGHPTE
	.kmap_atomic_pte = kmap_atomic,
#endif

#ifdef CONFIG_X86_PAE
	.set_pte_atomic = native_set_pte_atomic,
	.set_pte_present = native_set_pte_present,
	.set_pud = native_set_pud,
	.pte_clear = native_pte_clear,
	.pmd_clear = native_pmd_clear,

	.pmd_val = native_pmd_val,
	.make_pmd = native_make_pmd,
#endif

	.pte_val = native_pte_val,
	.pgd_val = native_pgd_val,

	.make_pte = native_make_pte,
	.make_pgd = native_make_pgd,

	.irq_enable_sysexit = native_irq_enable_sysexit,
	.iret = native_iret,

	.dup_mmap = paravirt_nop,
	.exit_mmap = paravirt_nop,
	.activate_mm = paravirt_nop,
};

EXPORT_SYMBOL(paravirt_ops);