fault.c 26.5 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
/*
 *  Copyright (C) 1995  Linus Torvalds
Ingo Molnar's avatar
Ingo Molnar committed
3
 *  Copyright (C) 2001, 2002 Andi Kleen, SuSE Labs.
Linus Torvalds's avatar
Linus Torvalds committed
4
5
 */
#include <linux/interrupt.h>
Ingo Molnar's avatar
Ingo Molnar committed
6
7
#include <linux/mmiotrace.h>
#include <linux/bootmem.h>
Linus Torvalds's avatar
Linus Torvalds committed
8
#include <linux/compiler.h>
Harvey Harrison's avatar
Harvey Harrison committed
9
#include <linux/highmem.h>
10
#include <linux/kprobes.h>
11
#include <linux/uaccess.h>
Ingo Molnar's avatar
Ingo Molnar committed
12
13
14
15
16
17
18
#include <linux/vmalloc.h>
#include <linux/vt_kern.h>
#include <linux/signal.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <linux/module.h>
19
#include <linux/kdebug.h>
Ingo Molnar's avatar
Ingo Molnar committed
20
#include <linux/errno.h>
21
#include <linux/magic.h>
Ingo Molnar's avatar
Ingo Molnar committed
22
23
24
25
26
27
28
29
30
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/mman.h>
#include <linux/tty.h>
#include <linux/smp.h>
#include <linux/mm.h>

#include <asm-generic/sections.h>
Linus Torvalds's avatar
Linus Torvalds committed
31
32

#include <asm/tlbflush.h>
Ingo Molnar's avatar
Ingo Molnar committed
33
34
35
#include <asm/pgalloc.h>
#include <asm/segment.h>
#include <asm/system.h>
Linus Torvalds's avatar
Linus Torvalds committed
36
#include <asm/proto.h>
37
#include <asm/traps.h>
Ingo Molnar's avatar
Ingo Molnar committed
38
#include <asm/desc.h>
Linus Torvalds's avatar
Linus Torvalds committed
39

40
/*
Ingo Molnar's avatar
Ingo Molnar committed
41
42
43
44
45
46
47
 * Page fault error code bits:
 *
 *   bit 0 ==	 0: no page found	1: protection fault
 *   bit 1 ==	 0: read access		1: write access
 *   bit 2 ==	 0: kernel-mode access	1: user-mode access
 *   bit 3 ==				1: use of reserved bit detected
 *   bit 4 ==				1: fault was an instruction fetch
48
 */
Ingo Molnar's avatar
Ingo Molnar committed
49
50
51
52
53
54
55
56
enum x86_pf_error_code {

	PF_PROT		=		1 << 0,
	PF_WRITE	=		1 << 1,
	PF_USER		=		1 << 2,
	PF_RSVD		=		1 << 3,
	PF_INSTR	=		1 << 4,
};
57

58
59
60
/*
 * (returns 0 if mmiotrace is disabled)
 */
61
static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
62
{
63
64
65
66
	if (unlikely(is_kmmio_active()))
		if (kmmio_handler(regs, addr) == 1)
			return -1;
	return 0;
67
68
}

69
static inline int notify_page_fault(struct pt_regs *regs)
70
{
71
72
73
	int ret = 0;

	/* kprobe_running() needs smp_processor_id() */
74
	if (kprobes_built_in() && !user_mode_vm(regs)) {
75
76
77
78
79
		preempt_disable();
		if (kprobe_running() && kprobe_fault_handler(regs, 14))
			ret = 1;
		preempt_enable();
	}
80

81
	return ret;
82
}
83

84
/*
Ingo Molnar's avatar
Ingo Molnar committed
85
86
87
88
89
90
 * Prefetch quirks:
 *
 * 32-bit mode:
 *
 *   Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
 *   Check that here and ignore it.
91
 *
Ingo Molnar's avatar
Ingo Molnar committed
92
 * 64-bit mode:
93
 *
Ingo Molnar's avatar
Ingo Molnar committed
94
95
96
97
 *   Sometimes the CPU reports invalid exceptions on prefetch.
 *   Check that here and ignore it.
 *
 * Opcode checker based on code by Richard Brunner.
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
static inline int
check_prefetch_opcode(struct pt_regs *regs, unsigned char *instr,
		      unsigned char opcode, int *prefetch)
{
	unsigned char instr_hi = opcode & 0xf0;
	unsigned char instr_lo = opcode & 0x0f;

	switch (instr_hi) {
	case 0x20:
	case 0x30:
		/*
		 * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
		 * In X86_64 long mode, the CPU will signal invalid
		 * opcode if some of these prefixes are present so
		 * X86_64 will never get here anyway
		 */
		return ((instr_lo & 7) == 0x6);
#ifdef CONFIG_X86_64
	case 0x40:
		/*
		 * In AMD64 long mode 0x40..0x4F are valid REX prefixes
		 * Need to figure out under what instruction mode the
		 * instruction was issued. Could check the LDT for lm,
		 * but for now it's good enough to assume that long
		 * mode only uses well known segments or kernel.
		 */
		return (!user_mode(regs)) || (regs->cs == __USER_CS);
#endif
	case 0x60:
		/* 0x64 thru 0x67 are valid prefixes in all modes. */
		return (instr_lo & 0xC) == 0x4;
	case 0xF0:
		/* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */
		return !instr_lo || (instr_lo>>1) == 1;
	case 0x00:
		/* Prefetch instruction is 0x0F0D or 0x0F18 */
		if (probe_kernel_address(instr, opcode))
			return 0;

		*prefetch = (instr_lo == 0xF) &&
			(opcode == 0x0D || opcode == 0x18);
		return 0;
	default:
		return 0;
	}
}

Ingo Molnar's avatar
Ingo Molnar committed
146
147
static int
is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
148
{
Ingo Molnar's avatar
Ingo Molnar committed
149
	unsigned char *max_instr;
150
	unsigned char *instr;
151
	int prefetch = 0;
Linus Torvalds's avatar
Linus Torvalds committed
152

Ingo Molnar's avatar
Ingo Molnar committed
153
154
155
156
	/*
	 * If it was a exec (instruction fetch) fault on NX page, then
	 * do not ignore the fault:
	 */
157
	if (error_code & PF_INSTR)
Linus Torvalds's avatar
Linus Torvalds committed
158
		return 0;
159

160
	instr = (void *)convert_ip_to_linear(current, regs);
161
	max_instr = instr + 15;
Linus Torvalds's avatar
Linus Torvalds committed
162

163
	if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
Linus Torvalds's avatar
Linus Torvalds committed
164
165
		return 0;

166
	while (instr < max_instr) {
Ingo Molnar's avatar
Ingo Molnar committed
167
		unsigned char opcode;
Linus Torvalds's avatar
Linus Torvalds committed
168

169
		if (probe_kernel_address(instr, opcode))
170
			break;
Linus Torvalds's avatar
Linus Torvalds committed
171
172
173

		instr++;

174
		if (!check_prefetch_opcode(regs, instr, opcode, &prefetch))
Linus Torvalds's avatar
Linus Torvalds committed
175
176
177
178
179
			break;
	}
	return prefetch;
}

Ingo Molnar's avatar
Ingo Molnar committed
180
181
182
static void
force_sig_info_fault(int si_signo, int si_code, unsigned long address,
		     struct task_struct *tsk)
183
184
185
{
	siginfo_t info;

Ingo Molnar's avatar
Ingo Molnar committed
186
187
188
189
190
	info.si_signo	= si_signo;
	info.si_errno	= 0;
	info.si_code	= si_code;
	info.si_addr	= (void __user *)address;

191
192
193
	force_sig_info(si_signo, &info, tsk);
}

194
#ifdef CONFIG_X86_64
195
196
static int bad_address(void *p)
{
Linus Torvalds's avatar
Linus Torvalds committed
197
	unsigned long dummy;
Ingo Molnar's avatar
Ingo Molnar committed
198

199
	return probe_kernel_address((unsigned long *)p, dummy);
200
}
201
#endif
Linus Torvalds's avatar
Linus Torvalds committed
202

203
static void dump_pagetable(unsigned long address)
Linus Torvalds's avatar
Linus Torvalds committed
204
{
205
206
207
208
209
#ifdef CONFIG_X86_32
	__typeof__(pte_val(__pte(0))) page;

	page = read_cr3();
	page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT];
Ingo Molnar's avatar
Ingo Molnar committed
210

211
212
213
214
215
216
#ifdef CONFIG_X86_PAE
	printk("*pdpt = %016Lx ", page);
	if ((page >> PAGE_SHIFT) < max_low_pfn
	    && page & _PAGE_PRESENT) {
		page &= PAGE_MASK;
		page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT)
Ingo Molnar's avatar
Ingo Molnar committed
217
							& (PTRS_PER_PMD - 1)];
218
219
220
221
222
223
224
225
226
227
228
		printk(KERN_CONT "*pde = %016Lx ", page);
		page &= ~_PAGE_NX;
	}
#else
	printk("*pde = %08lx ", page);
#endif

	/*
	 * We must not directly access the pte in the highpte
	 * case if the page table is located in highmem.
	 * And let's rather not kmap-atomic the pte, just in case
Ingo Molnar's avatar
Ingo Molnar committed
229
	 * it's allocated already:
230
231
232
233
	 */
	if ((page >> PAGE_SHIFT) < max_low_pfn
	    && (page & _PAGE_PRESENT)
	    && !(page & _PAGE_PSE)) {
Ingo Molnar's avatar
Ingo Molnar committed
234

235
236
		page &= PAGE_MASK;
		page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT)
Ingo Molnar's avatar
Ingo Molnar committed
237
							& (PTRS_PER_PTE - 1)];
238
239
240
241
242
		printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page);
	}

	printk("\n");
#else /* CONFIG_X86_64 */
Linus Torvalds's avatar
Linus Torvalds committed
243
244
245
246
247
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

248
	pgd = (pgd_t *)read_cr3();
Linus Torvalds's avatar
Linus Torvalds committed
249

250
	pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
Ingo Molnar's avatar
Ingo Molnar committed
251

Linus Torvalds's avatar
Linus Torvalds committed
252
	pgd += pgd_index(address);
Ingo Molnar's avatar
Ingo Molnar committed
253
254
255
	if (bad_address(pgd))
		goto bad;

256
	printk("PGD %lx ", pgd_val(*pgd));
Ingo Molnar's avatar
Ingo Molnar committed
257
258
259

	if (!pgd_present(*pgd))
		goto out;
Linus Torvalds's avatar
Linus Torvalds committed
260

261
	pud = pud_offset(pgd, address);
Ingo Molnar's avatar
Ingo Molnar committed
262
263
264
	if (bad_address(pud))
		goto bad;

Linus Torvalds's avatar
Linus Torvalds committed
265
	printk("PUD %lx ", pud_val(*pud));
266
	if (!pud_present(*pud) || pud_large(*pud))
Ingo Molnar's avatar
Ingo Molnar committed
267
		goto out;
Linus Torvalds's avatar
Linus Torvalds committed
268
269

	pmd = pmd_offset(pud, address);
Ingo Molnar's avatar
Ingo Molnar committed
270
271
272
	if (bad_address(pmd))
		goto bad;

Linus Torvalds's avatar
Linus Torvalds committed
273
	printk("PMD %lx ", pmd_val(*pmd));
Ingo Molnar's avatar
Ingo Molnar committed
274
275
	if (!pmd_present(*pmd) || pmd_large(*pmd))
		goto out;
Linus Torvalds's avatar
Linus Torvalds committed
276
277

	pte = pte_offset_kernel(pmd, address);
Ingo Molnar's avatar
Ingo Molnar committed
278
279
280
	if (bad_address(pte))
		goto bad;

281
	printk("PTE %lx", pte_val(*pte));
Ingo Molnar's avatar
Ingo Molnar committed
282
out:
Linus Torvalds's avatar
Linus Torvalds committed
283
284
285
286
	printk("\n");
	return;
bad:
	printk("BAD\n");
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
#endif
}

#ifdef CONFIG_X86_32
static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
{
	unsigned index = pgd_index(address);
	pgd_t *pgd_k;
	pud_t *pud, *pud_k;
	pmd_t *pmd, *pmd_k;

	pgd += index;
	pgd_k = init_mm.pgd + index;

	if (!pgd_present(*pgd_k))
		return NULL;

	/*
	 * set_pgd(pgd, *pgd_k); here would be useless on PAE
	 * and redundant with the set_pmd() on non-PAE. As would
	 * set_pud.
	 */
	pud = pud_offset(pgd, address);
	pud_k = pud_offset(pgd_k, address);
	if (!pud_present(*pud_k))
		return NULL;

	pmd = pmd_offset(pud, address);
	pmd_k = pmd_offset(pud_k, address);
	if (!pmd_present(*pmd_k))
		return NULL;
Ingo Molnar's avatar
Ingo Molnar committed
318

319
320
321
	if (!pmd_present(*pmd)) {
		set_pmd(pmd, *pmd_k);
		arch_flush_lazy_mmu_mode();
Ingo Molnar's avatar
Ingo Molnar committed
322
	} else {
323
		BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
Ingo Molnar's avatar
Ingo Molnar committed
324
325
	}

326
	return pmd_k;
Linus Torvalds's avatar
Linus Torvalds committed
327
328
}

329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
/*
 * Did it hit the DOS screen memory VA from vm86 mode?
 */
static inline void
check_v8086_mode(struct pt_regs *regs, unsigned long address,
		 struct task_struct *tsk)
{
	unsigned long bit;

	if (!v8086_mode(regs))
		return;

	bit = (address - 0xA0000) >> PAGE_SHIFT;
	if (bit < 32)
		tsk->thread.screen_bitmap |= 1 << bit;
}

#else /* CONFIG_X86_64: */

348
static const char errata93_warning[] =
Linus Torvalds's avatar
Linus Torvalds committed
349
350
351
352
KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
KERN_ERR "******* Please consider a BIOS update.\n"
KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
353
354
355
356
357
358
359
360
361
362

/*
 * No vm86 mode in 64-bit mode:
 */
static inline void
check_v8086_mode(struct pt_regs *regs, unsigned long address,
		 struct task_struct *tsk)
{
}

363
#endif
Linus Torvalds's avatar
Linus Torvalds committed
364

Ingo Molnar's avatar
Ingo Molnar committed
365
366
367
368
369
370
371
372
373
374
375
376
377
/*
 * Workaround for K8 erratum #93 & buggy BIOS.
 *
 * BIOS SMM functions are required to use a specific workaround
 * to avoid corruption of the 64bit RIP register on C stepping K8.
 *
 * A lot of BIOS that didn't get tested properly miss this.
 *
 * The OS sees this as a page fault with the upper 32bits of RIP cleared.
 * Try to work around it here.
 *
 * Note we only handle faults in kernel here.
 * Does nothing on 32-bit.
378
 */
379
static int is_errata93(struct pt_regs *regs, unsigned long address)
Linus Torvalds's avatar
Linus Torvalds committed
380
{
381
#ifdef CONFIG_X86_64
Ingo Molnar's avatar
Ingo Molnar committed
382
383
	static int once;

384
	if (address != regs->ip)
Linus Torvalds's avatar
Linus Torvalds committed
385
		return 0;
Ingo Molnar's avatar
Ingo Molnar committed
386

387
	if ((address >> 32) != 0)
Linus Torvalds's avatar
Linus Torvalds committed
388
		return 0;
Ingo Molnar's avatar
Ingo Molnar committed
389

Linus Torvalds's avatar
Linus Torvalds committed
390
	address |= 0xffffffffUL << 32;
391
392
	if ((address >= (u64)_stext && address <= (u64)_etext) ||
	    (address >= MODULES_VADDR && address <= MODULES_END)) {
Ingo Molnar's avatar
Ingo Molnar committed
393
		if (!once) {
394
			printk(errata93_warning);
Ingo Molnar's avatar
Ingo Molnar committed
395
			once = 1;
Linus Torvalds's avatar
Linus Torvalds committed
396
		}
397
		regs->ip = address;
Linus Torvalds's avatar
Linus Torvalds committed
398
399
		return 1;
	}
400
#endif
Linus Torvalds's avatar
Linus Torvalds committed
401
	return 0;
402
}
Linus Torvalds's avatar
Linus Torvalds committed
403

404
/*
Ingo Molnar's avatar
Ingo Molnar committed
405
406
407
408
409
 * Work around K8 erratum #100 K8 in compat mode occasionally jumps
 * to illegal addresses >4GB.
 *
 * We catch this in the page fault handler because these addresses
 * are not reachable. Just detect this case and return.  Any code
410
411
412
413
414
 * segment in LDT is compatibility mode.
 */
static int is_errata100(struct pt_regs *regs, unsigned long address)
{
#ifdef CONFIG_X86_64
Ingo Molnar's avatar
Ingo Molnar committed
415
	if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) && (address >> 32))
416
417
418
419
420
		return 1;
#endif
	return 0;
}

421
422
423
424
static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
{
#ifdef CONFIG_X86_F00F_BUG
	unsigned long nr;
Ingo Molnar's avatar
Ingo Molnar committed
425

426
	/*
Ingo Molnar's avatar
Ingo Molnar committed
427
	 * Pentium F0 0F C7 C8 bug workaround:
428
429
430
431
432
433
434
435
436
437
438
439
440
	 */
	if (boot_cpu_data.f00f_bug) {
		nr = (address - idt_descr.address) >> 3;

		if (nr == 6) {
			do_invalid_op(regs, 0);
			return 1;
		}
	}
#endif
	return 0;
}

Ingo Molnar's avatar
Ingo Molnar committed
441
442
443
static void
show_fault_oops(struct pt_regs *regs, unsigned long error_code,
		unsigned long address)
444
{
445
446
447
#ifdef CONFIG_X86_32
	if (!oops_may_print())
		return;
448
#endif
449
450
451

#ifdef CONFIG_X86_PAE
	if (error_code & PF_INSTR) {
452
		unsigned int level;
Ingo Molnar's avatar
Ingo Molnar committed
453

454
455
		pte_t *pte = lookup_address(address, &level);

Ingo Molnar's avatar
Ingo Molnar committed
456
		if (pte && pte_present(*pte) && !pte_exec(*pte)) {
457
458
			printk(KERN_CRIT "kernel tried to execute "
				"NX-protected page - exploit attempt? "
459
				"(uid: %d)\n", current_uid());
Ingo Molnar's avatar
Ingo Molnar committed
460
		}
461
462
463
	}
#endif

464
	printk(KERN_ALERT "BUG: unable to handle kernel ");
465
	if (address < PAGE_SIZE)
466
		printk(KERN_CONT "NULL pointer dereference");
467
	else
468
		printk(KERN_CONT "paging request");
Ingo Molnar's avatar
Ingo Molnar committed
469

470
	printk(KERN_CONT " at %p\n", (void *) address);
471
	printk(KERN_ALERT "IP:");
472
	printk_address(regs->ip, 1);
Ingo Molnar's avatar
Ingo Molnar committed
473

474
475
476
	dump_pagetable(address);
}

Ingo Molnar's avatar
Ingo Molnar committed
477
478
479
static noinline void
pgtable_bad(struct pt_regs *regs, unsigned long error_code,
	    unsigned long address)
Linus Torvalds's avatar
Linus Torvalds committed
480
{
Ingo Molnar's avatar
Ingo Molnar committed
481
482
483
484
485
486
487
	struct task_struct *tsk;
	unsigned long flags;
	int sig;

	flags = oops_begin();
	tsk = current;
	sig = SIGKILL;
488

Linus Torvalds's avatar
Linus Torvalds committed
489
	printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
490
	       tsk->comm, address);
Linus Torvalds's avatar
Linus Torvalds committed
491
	dump_pagetable(address);
Ingo Molnar's avatar
Ingo Molnar committed
492
493
494
495
496

	tsk->thread.cr2		= address;
	tsk->thread.trap_no	= 14;
	tsk->thread.error_code	= error_code;

497
	if (__die("Bad pagetable", regs, error_code))
498
		sig = 0;
Ingo Molnar's avatar
Ingo Molnar committed
499

500
	oops_end(flags, regs, sig);
Linus Torvalds's avatar
Linus Torvalds committed
501
502
}

Ingo Molnar's avatar
Ingo Molnar committed
503
504
505
static noinline void
no_context(struct pt_regs *regs, unsigned long error_code,
	   unsigned long address)
506
507
{
	struct task_struct *tsk = current;
508
509
	unsigned long *stackend;

510
511
512
513
514
#ifdef CONFIG_X86_64
	unsigned long flags;
	int sig;
#endif

Ingo Molnar's avatar
Ingo Molnar committed
515
	/* Are we prepared to handle this kernel fault? */
516
517
518
519
	if (fixup_exception(regs))
		return;

	/*
Ingo Molnar's avatar
Ingo Molnar committed
520
521
522
523
524
525
526
	 * 32-bit:
	 *
	 *   Valid to do another page fault here, because if this fault
	 *   had been triggered by is_prefetch fixup_exception would have
	 *   handled it.
	 *
	 * 64-bit:
527
	 *
Ingo Molnar's avatar
Ingo Molnar committed
528
	 *   Hall of shame of CPU/BIOS bugs.
529
530
531
532
533
534
535
536
537
	 */
	if (is_prefetch(regs, error_code, address))
		return;

	if (is_errata93(regs, address))
		return;

	/*
	 * Oops. The kernel tried to access some bad page. We'll have to
Ingo Molnar's avatar
Ingo Molnar committed
538
	 * terminate things with extreme prejudice:
539
540
541
542
543
544
545
546
547
	 */
#ifdef CONFIG_X86_32
	bust_spinlocks(1);
#else
	flags = oops_begin();
#endif

	show_fault_oops(regs, error_code, address);

Ingo Molnar's avatar
Ingo Molnar committed
548
	stackend = end_of_stack(tsk);
549
550
551
	if (*stackend != STACK_END_MAGIC)
		printk(KERN_ALERT "Thread overran stack, or stack corrupted\n");

552
553
554
555
556
557
558
559
560
561
562
563
	tsk->thread.cr2 = address;
	tsk->thread.trap_no = 14;
	tsk->thread.error_code = error_code;

#ifdef CONFIG_X86_32
	die("Oops", regs, error_code);
	bust_spinlocks(0);
	do_exit(SIGKILL);
#else
	sig = SIGKILL;
	if (__die("Oops", regs, error_code))
		sig = 0;
Ingo Molnar's avatar
Ingo Molnar committed
564

565
566
	/* Executive summary in case the body of the oops scrolled away */
	printk(KERN_EMERG "CR2: %016lx\n", address);
Ingo Molnar's avatar
Ingo Molnar committed
567

568
569
570
571
	oops_end(flags, regs, sig);
#endif
}

Ingo Molnar's avatar
Ingo Molnar committed
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
/*
 * Print out info about fatal segfaults, if the show_unhandled_signals
 * sysctl is set:
 */
static inline void
show_signal_msg(struct pt_regs *regs, unsigned long error_code,
		unsigned long address, struct task_struct *tsk)
{
	if (!unhandled_signal(tsk, SIGSEGV))
		return;

	if (!printk_ratelimit())
		return;

	printk(KERN_CONT "%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
		task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
		tsk->comm, task_pid_nr(tsk), address,
		(void *)regs->ip, (void *)regs->sp, error_code);

	print_vma_addr(KERN_CONT " in ", regs->ip);

	printk(KERN_CONT "\n");
}

static void
__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
		       unsigned long address, int si_code)
599
600
601
602
603
604
{
	struct task_struct *tsk = current;

	/* User mode accesses just cause a SIGSEGV */
	if (error_code & PF_USER) {
		/*
Ingo Molnar's avatar
Ingo Molnar committed
605
		 * It's possible to have interrupts off here:
606
607
608
609
610
		 */
		local_irq_enable();

		/*
		 * Valid to do another page fault here because this one came
Ingo Molnar's avatar
Ingo Molnar committed
611
		 * from user space:
612
613
614
615
616
617
618
		 */
		if (is_prefetch(regs, error_code, address))
			return;

		if (is_errata100(regs, address))
			return;

Ingo Molnar's avatar
Ingo Molnar committed
619
620
621
622
623
624
625
		if (unlikely(show_unhandled_signals))
			show_signal_msg(regs, error_code, address, tsk);

		/* Kernel addresses are always protection faults: */
		tsk->thread.cr2		= address;
		tsk->thread.error_code	= error_code | (address >= TASK_SIZE);
		tsk->thread.trap_no	= 14;
626
627

		force_sig_info_fault(SIGSEGV, si_code, address, tsk);
Ingo Molnar's avatar
Ingo Molnar committed
628

629
630
631
632
633
634
635
636
637
		return;
	}

	if (is_f00f_bug(regs, address))
		return;

	no_context(regs, error_code, address);
}

Ingo Molnar's avatar
Ingo Molnar committed
638
639
640
static noinline void
bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
		     unsigned long address)
641
642
643
644
{
	__bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
}

Ingo Molnar's avatar
Ingo Molnar committed
645
646
647
static void
__bad_area(struct pt_regs *regs, unsigned long error_code,
	   unsigned long address, int si_code)
648
649
650
651
652
653
654
655
656
657
658
659
{
	struct mm_struct *mm = current->mm;

	/*
	 * Something tried to access memory that isn't in our memory map..
	 * Fix it, but check if it's kernel or user first..
	 */
	up_read(&mm->mmap_sem);

	__bad_area_nosemaphore(regs, error_code, address, si_code);
}

Ingo Molnar's avatar
Ingo Molnar committed
660
661
static noinline void
bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
662
663
664
665
{
	__bad_area(regs, error_code, address, SEGV_MAPERR);
}

Ingo Molnar's avatar
Ingo Molnar committed
666
667
668
static noinline void
bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
		      unsigned long address)
669
670
671
672
673
{
	__bad_area(regs, error_code, address, SEGV_ACCERR);
}

/* TODO: fixup for "mm-invoke-oom-killer-from-page-fault.patch" */
Ingo Molnar's avatar
Ingo Molnar committed
674
675
676
static void
out_of_memory(struct pt_regs *regs, unsigned long error_code,
	      unsigned long address)
677
678
679
{
	/*
	 * We ran out of memory, call the OOM killer, and return the userspace
Ingo Molnar's avatar
Ingo Molnar committed
680
	 * (which will retry the fault, or kill us if we got oom-killed):
681
682
	 */
	up_read(&current->mm->mmap_sem);
Ingo Molnar's avatar
Ingo Molnar committed
683

684
685
686
	pagefault_out_of_memory();
}

Ingo Molnar's avatar
Ingo Molnar committed
687
688
static void
do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
689
690
691
692
693
694
{
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->mm;

	up_read(&mm->mmap_sem);

Ingo Molnar's avatar
Ingo Molnar committed
695
	/* Kernel mode? Handle exceptions or die: */
696
697
	if (!(error_code & PF_USER))
		no_context(regs, error_code, address);
Ingo Molnar's avatar
Ingo Molnar committed
698

699
#ifdef CONFIG_X86_32
Ingo Molnar's avatar
Ingo Molnar committed
700
	/* User space => ok to do another page fault: */
701
702
703
	if (is_prefetch(regs, error_code, address))
		return;
#endif
Ingo Molnar's avatar
Ingo Molnar committed
704
705
706
707
708

	tsk->thread.cr2		= address;
	tsk->thread.error_code	= error_code;
	tsk->thread.trap_no	= 14;

709
710
711
	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
}

Ingo Molnar's avatar
Ingo Molnar committed
712
713
714
static noinline void
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
	       unsigned long address, unsigned int fault)
715
{
Ingo Molnar's avatar
Ingo Molnar committed
716
	if (fault & VM_FAULT_OOM) {
717
		out_of_memory(regs, error_code, address);
Ingo Molnar's avatar
Ingo Molnar committed
718
719
720
721
722
723
	} else {
		if (fault & VM_FAULT_SIGBUS)
			do_sigbus(regs, error_code, address);
		else
			BUG();
	}
724
725
}

726
727
728
729
static int spurious_fault_check(unsigned long error_code, pte_t *pte)
{
	if ((error_code & PF_WRITE) && !pte_write(*pte))
		return 0;
Ingo Molnar's avatar
Ingo Molnar committed
730

731
732
733
734
735
736
	if ((error_code & PF_INSTR) && !pte_exec(*pte))
		return 0;

	return 1;
}

737
/*
Ingo Molnar's avatar
Ingo Molnar committed
738
739
740
741
742
743
744
745
 * Handle a spurious fault caused by a stale TLB entry.
 *
 * This allows us to lazily refresh the TLB when increasing the
 * permissions of a kernel page (RO -> RW or NX -> X).  Doing it
 * eagerly is very expensive since that implies doing a full
 * cross-processor TLB flush, even if no stale TLB entries exist
 * on other processors.
 *
746
747
748
 * There are no security implications to leaving a stale TLB when
 * increasing the permissions on a page.
 */
Ingo Molnar's avatar
Ingo Molnar committed
749
750
static noinline int
spurious_fault(unsigned long error_code, unsigned long address)
751
752
753
754
755
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
756
	int ret;
757
758
759
760
761
762
763
764
765
766
767
768
769

	/* Reserved-bit violation or user access to kernel space? */
	if (error_code & (PF_USER | PF_RSVD))
		return 0;

	pgd = init_mm.pgd + pgd_index(address);
	if (!pgd_present(*pgd))
		return 0;

	pud = pud_offset(pgd, address);
	if (!pud_present(*pud))
		return 0;

770
771
772
	if (pud_large(*pud))
		return spurious_fault_check(error_code, (pte_t *) pud);

773
774
775
776
	pmd = pmd_offset(pud, address);
	if (!pmd_present(*pmd))
		return 0;

777
778
779
	if (pmd_large(*pmd))
		return spurious_fault_check(error_code, (pte_t *) pmd);

780
781
782
783
	pte = pte_offset_kernel(pmd, address);
	if (!pte_present(*pte))
		return 0;

784
785
786
787
788
	ret = spurious_fault_check(error_code, pte);
	if (!ret)
		return 0;

	/*
Ingo Molnar's avatar
Ingo Molnar committed
789
790
	 * Make sure we have permissions in PMD.
	 * If not, then there's a bug in the page tables:
791
792
793
	 */
	ret = spurious_fault_check(error_code, (pte_t *) pmd);
	WARN_ONCE(!ret, "PMD has incorrect permission bits\n");
Ingo Molnar's avatar
Ingo Molnar committed
794

795
	return ret;
796
797
}

Linus Torvalds's avatar
Linus Torvalds committed
798
/*
Ingo Molnar's avatar
Ingo Molnar committed
799
800
801
 * 32-bit:
 *
 *   Handle a fault on the vmalloc or module mapping area
802
 *
Ingo Molnar's avatar
Ingo Molnar committed
803
804
805
 * 64-bit:
 *
 *   Handle a fault on the vmalloc area
806
807
 *
 * This assumes no large pages in there.
Linus Torvalds's avatar
Linus Torvalds committed
808
 */
809
static noinline int vmalloc_fault(unsigned long address)
Linus Torvalds's avatar
Linus Torvalds committed
810
{
811
812
813
814
#ifdef CONFIG_X86_32
	unsigned long pgd_paddr;
	pmd_t *pmd_k;
	pte_t *pte_k;
815

Ingo Molnar's avatar
Ingo Molnar committed
816
	/* Make sure we are in vmalloc area: */
817
818
819
	if (!(address >= VMALLOC_START && address < VMALLOC_END))
		return -1;

820
821
822
823
824
825
826
827
828
829
830
	/*
	 * Synchronize this task's top level page-table
	 * with the 'reference' page table.
	 *
	 * Do _not_ use "current" here. We might be inside
	 * an interrupt in the middle of a task switch..
	 */
	pgd_paddr = read_cr3();
	pmd_k = vmalloc_sync_one(__va(pgd_paddr), address);
	if (!pmd_k)
		return -1;
Ingo Molnar's avatar
Ingo Molnar committed
831

832
833
834
	pte_k = pte_offset_kernel(pmd_k, address);
	if (!pte_present(*pte_k))
		return -1;
Ingo Molnar's avatar
Ingo Molnar committed
835

836
837
	return 0;
#else
Linus Torvalds's avatar
Linus Torvalds committed
838
839
840
841
842
	pgd_t *pgd, *pgd_ref;
	pud_t *pud, *pud_ref;
	pmd_t *pmd, *pmd_ref;
	pte_t *pte, *pte_ref;

Ingo Molnar's avatar
Ingo Molnar committed
843
	/* Make sure we are in vmalloc area: */
844
845
846
	if (!(address >= VMALLOC_START && address < VMALLOC_END))
		return -1;

Ingo Molnar's avatar
Ingo Molnar committed
847
848
849
850
851
	/*
	 * Copy kernel mappings over when needed. This can also
	 * happen within a race in page table update. In the later
	 * case just flush:
	 */
852
	pgd = pgd_offset(current->active_mm, address);
Linus Torvalds's avatar
Linus Torvalds committed
853
854
855
	pgd_ref = pgd_offset_k(address);
	if (pgd_none(*pgd_ref))
		return -1;
Ingo Molnar's avatar
Ingo Molnar committed
856

Linus Torvalds's avatar
Linus Torvalds committed
857
858
	if (pgd_none(*pgd))
		set_pgd(pgd, *pgd_ref);
859
	else
860
		BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
Linus Torvalds's avatar
Linus Torvalds committed
861

Ingo Molnar's avatar
Ingo Molnar committed
862
863
864
865
	/*
	 * Below here mismatches are bugs because these lower tables
	 * are shared:
	 */
Linus Torvalds's avatar
Linus Torvalds committed
866
867
868
869
870

	pud = pud_offset(pgd, address);
	pud_ref = pud_offset(pgd_ref, address);
	if (pud_none(*pud_ref))
		return -1;
Ingo Molnar's avatar
Ingo Molnar committed
871

872
	if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
Linus Torvalds's avatar
Linus Torvalds committed
873
		BUG();
Ingo Molnar's avatar
Ingo Molnar committed
874

Linus Torvalds's avatar
Linus Torvalds committed
875
876
877
878
	pmd = pmd_offset(pud, address);
	pmd_ref = pmd_offset(pud_ref, address);
	if (pmd_none(*pmd_ref))
		return -1;
Ingo Molnar's avatar
Ingo Molnar committed
879

Linus Torvalds's avatar
Linus Torvalds committed
880
881
	if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
		BUG();
Ingo Molnar's avatar
Ingo Molnar committed
882

Linus Torvalds's avatar
Linus Torvalds committed
883
884
885
	pte_ref = pte_offset_kernel(pmd_ref, address);
	if (!pte_present(*pte_ref))
		return -1;
Ingo Molnar's avatar
Ingo Molnar committed
886

Linus Torvalds's avatar
Linus Torvalds committed
887
	pte = pte_offset_kernel(pmd, address);
Ingo Molnar's avatar
Ingo Molnar committed
888
889
890
891
892
893

	/*
	 * Don't use pte_page here, because the mappings can point
	 * outside mem_map, and the NUMA hash lookup cannot handle
	 * that:
	 */
894
	if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
Linus Torvalds's avatar
Linus Torvalds committed
895
		BUG();
Ingo Molnar's avatar
Ingo Molnar committed
896

Linus Torvalds's avatar
Linus Torvalds committed
897
	return 0;
898
#endif
Linus Torvalds's avatar
Linus Torvalds committed
899
900
}

901
int show_unhandled_signals = 1;
Linus Torvalds's avatar
Linus Torvalds committed
902

Ingo Molnar's avatar
Ingo Molnar committed
903
904
static inline int
access_error(unsigned long error_code, int write, struct vm_area_struct *vma)
905
906
{
	if (write) {
Ingo Molnar's avatar
Ingo Molnar committed
907
		/* write, present and write, not present: */
908
909
		if (unlikely(!(vma->vm_flags & VM_WRITE)))
			return 1;
Ingo Molnar's avatar
Ingo Molnar committed
910
		return 0;
911
912
	}

Ingo Molnar's avatar
Ingo Molnar committed
913
914
915
916
917
918
919
920
	/* read, present: */
	if (unlikely(error_code & PF_PROT))
		return 1;

	/* read, not present: */
	if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
		return 1;

921
922
923
	return 0;
}

924
925
926
927
static int fault_in_kernel_space(unsigned long address)
{
#ifdef CONFIG_X86_32
	return address >= TASK_SIZE;
Ingo Molnar's avatar
Ingo Molnar committed
928
#else
929
	return address >= TASK_SIZE64;
Ingo Molnar's avatar
Ingo Molnar committed
930
#endif
931
932
}

Linus Torvalds's avatar
Linus Torvalds committed
933
934
935
936
937
/*
 * This routine handles page faults.  It determines the address,
 * and the problem, and then passes it off to one of the appropriate
 * routines.
 */
938
939
940
941
#ifdef CONFIG_X86_64
asmlinkage
#endif
void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
Linus Torvalds's avatar
Linus Torvalds committed
942
{
Ingo Molnar's avatar
Ingo Molnar committed
943
	struct vm_area_struct *vma;
Linus Torvalds's avatar
Linus Torvalds committed
944
	struct task_struct *tsk;
Ingo Molnar's avatar
Ingo Molnar committed
945
	unsigned long address;
Linus Torvalds's avatar
Linus Torvalds committed
946
	struct mm_struct *mm;
947
	int write;
948
	int fault;
Linus Torvalds's avatar
Linus Torvalds committed
949

950
951
	tsk = current;
	mm = tsk->mm;
Ingo Molnar's avatar
Ingo Molnar committed
952

953
954
	prefetchw(&mm->mmap_sem);

Ingo Molnar's avatar
Ingo Molnar committed
955
	/* Get the faulting address: */
956
	address = read_cr2();
Linus Torvalds's avatar
Linus Torvalds committed
957

958
	if (unlikely(kmmio_fault(regs, address)))
959
		return;
Linus Torvalds's avatar
Linus Torvalds committed
960
961
962
963
964
965
966
967
968
969
970
971

	/*
	 * We fault-in kernel-space virtual memory on-demand. The
	 * 'reference' page table is init_mm.pgd.
	 *
	 * NOTE! We MUST NOT take any locks for this case. We may
	 * be in an interrupt or a critical region, and should
	 * only copy the information from the master page table,
	 * nothing more.
	 *
	 * This verifies that the fault happens in kernel space
	 * (error_code & 4) == 0, and that the fault was not a
972
	 * protection error (error_code & 9) == 0.
Linus Torvalds's avatar
Linus Torvalds committed
973
	 */
974
	if (unlikely(fault_in_kernel_space(address))) {
975
976
977
		if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
		    vmalloc_fault(address) >= 0)
			return;
978

Ingo Molnar's avatar
Ingo Molnar committed
979
		/* Can handle a stale RO->RW TLB: */
980
		if (spurious_fault(error_code, address))
981
982
			return;

Ingo Molnar's avatar
Ingo Molnar committed
983
		/* kprobes don't want to hook the spurious faults: */
984
985
		if (notify_page_fault(regs))
			return;
986
987
		/*
		 * Don't take the mm semaphore here. If we fixup a prefetch
Ingo Molnar's avatar
Ingo Molnar committed
988
		 * fault we could otherwise deadlock:
989
		 */
990
		bad_area_nosemaphore(regs, error_code, address);
Ingo Molnar's avatar
Ingo Molnar committed
991

992
		return;
993
994
	}

Ingo Molnar's avatar
Ingo Molnar committed
995
	/* kprobes don't want to hook the spurious faults: */
996
	if (unlikely(notify_page_fault(regs)))
997
		return;
998
	/*
999
1000
1001
1002
	 * It's safe to allow irq's after cr2 has been saved and the
	 * vmalloc fault has been handled.
	 *
	 * User-mode registers count as a user access even for any
Ingo Molnar's avatar
Ingo Molnar committed
1003
	 * potential system fault or CPU buglet:
1004
	 */
1005
1006
1007
	if (user_mode_vm(regs)) {
		local_irq_enable();
		error_code |= PF_USER;
Ingo Molnar's avatar
Ingo Molnar committed
1008
1009
1010
1011
	} else {
		if (regs->flags & X86_EFLAGS_IF)
			local_irq_enable();
	}
1012

1013
	if (unlikely(error_code & PF_RSVD))
1014
		pgtable_bad(regs, error_code, address);
Linus Torvalds's avatar
Linus Torvalds committed
1015
1016

	/*
Ingo Molnar's avatar
Ingo Molnar committed
1017
1018
	 * If we're in an interrupt, have no user context or are running
	 * in an atomic region then we must not take the fault:
Linus Torvalds's avatar
Linus Torvalds committed
1019
	 */
1020
1021
1022
1023
	if (unlikely(in_atomic() || !mm)) {
		bad_area_nosemaphore(regs, error_code, address);
		return;
	}
Linus Torvalds's avatar
Linus Torvalds committed
1024

1025
1026
	/*
	 * When running in the kernel we expect faults to occur only to
Ingo Molnar's avatar
Ingo Molnar committed
1027
1028
1029
1030
1031
1032
1033
	 * addresses in user space.  All other faults represent errors in
	 * the kernel and should generate an OOPS.  Unfortunately, in the
	 * case of an erroneous fault occurring in a code path which already
	 * holds mmap_sem we will deadlock attempting to validate the fault
	 * against the address space.  Luckily the kernel only validly
	 * references user space from well defined areas of code, which are
	 * listed in the exceptions table.
Linus Torvalds's avatar
Linus Torvalds committed
1034
1035
	 *
	 * As the vast majority of faults will be valid we will only perform
Ingo Molnar's avatar
Ingo Molnar committed
1036
1037
1038
1039
	 * the source reference check when there is a possibility of a
	 * deadlock. Attempt to lock the address space, if we cannot we then
	 * validate the source. If this is invalid we can skip the address
	 * space check, thus avoiding the deadlock:
Linus Torvalds's avatar
Linus Torvalds committed
1040
	 */
1041
	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
1042
		if ((error_code & PF_USER) == 0 &&
1043
1044
1045
1046
		    !search_exception_tables(regs->ip)) {
			bad_area_nosemaphore(regs, error_code, address);
			return;
		}
Linus Torvalds's avatar
Linus Torvalds committed
1047
		down_read(&mm->mmap_sem);
1048
1049
	} else {
		/*
Ingo Molnar's avatar
Ingo Molnar committed
1050
1051
1052
		 * The above down_read_trylock() might have succeeded in
		 * which case we'll have missed the might_sleep() from
		 * down_read():
1053
1054
		 */
		might_sleep();
Linus Torvalds's avatar
Linus Torvalds committed
1055
1056
1057
	}

	vma = find_vma(mm, address);
1058
1059
1060
1061
1062
	if (unlikely(!vma)) {
		bad_area(regs, error_code, address);
		return;
	}
	if (likely(vma->vm_start <= address))
Linus Torvalds's avatar
Linus Torvalds committed
1063
		goto good_area;
1064
1065
1066
1067
	if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
		bad_area(regs, error_code, address);
		return;
	}
1068
	if (error_code & PF_USER) {
1069
1070
1071
		/*
		 * Accessing the stack below %sp is always a bug.
		 * The large cushion allows instructions like enter
Ingo Molnar's avatar
Ingo Molnar committed
1072
		 * and pusha to work. ("enter $65535, $31" pushes
1073
		 * 32 pointers and then decrements %sp by 65535.)
1074
		 */
1075
1076
1077
1078
		if (unlikely(address + 65536 + 32 * sizeof(unsigned long) < regs->sp)) {
			bad_area(regs, error_code, address);
			return;
		}
Linus Torvalds's avatar
Linus Torvalds committed
1079
	}
1080
1081
1082
1083
1084
1085
1086
1087
1088
	if (unlikely(expand_stack(vma, address))) {
		bad_area(regs, error_code, address);
		return;
	}

	/*
	 * Ok, we have a good vm_area for this memory access, so
	 * we can handle it..
	 */
Linus Torvalds's avatar
Linus Torvalds committed
1089
good_area:
1090
	write = error_code & PF_WRITE;
Ingo Molnar's avatar
Ingo Molnar committed
1091

1092
1093
1094
	if (unlikely(access_error(error_code, write, vma))) {
		bad_area_access_error(regs, error_code, address);
		return;
Linus Torvalds's avatar
Linus Torvalds committed
1095
1096
1097
1098
1099
	}

	/*
	 * If for any reason at all we couldn't handle the fault,
	 * make sure we exit gracefully rather than endlessly redo
Ingo Molnar's avatar
Ingo Molnar committed
1100
	 * the fault:
Linus Torvalds's avatar
Linus Torvalds committed
1101
	 */
Nick Piggin's avatar
Nick Piggin committed
1102
	fault = handle_mm_fault(mm, vma, address, write);
Ingo Molnar's avatar
Ingo Molnar committed
1103

Nick Piggin's avatar
Nick Piggin committed
1104
	if (unlikely(fault & VM_FAULT_ERROR)) {
1105
1106
		mm_fault_error(regs, error_code, address, fault);
		return;
Linus Torvalds's avatar
Linus Torvalds committed
1107
	}
Ingo Molnar's avatar
Ingo Molnar committed
1108

Nick Piggin's avatar
Nick Piggin committed
1109
1110
1111
1112
	if (fault & VM_FAULT_MAJOR)
		tsk->maj_flt++;
	else
		tsk->min_flt++;
1113

1114
1115
	check_v8086_mode(regs, address, tsk);

Linus Torvalds's avatar
Linus Torvalds committed
1116
1117
	up_read(&mm->mmap_sem);
}
1118

1119
DEFINE_SPINLOCK(pgd_lock);
1120
LIST_HEAD(pgd_list);
1121
1122
1123

void vmalloc_sync_all(void)
{
1124
1125
	unsigned long address;

1126
#ifdef CONFIG_X86_32
1127
1128
1129
	if (SHARED_KERNEL_PMD)
		return;

1130
1131
1132
	for (address = VMALLOC_START & PMD_MASK;
	     address >= TASK_SIZE && address < FIXADDR_TOP;
	     address += PMD_SIZE) {
Ingo Molnar's avatar
Ingo Molnar committed
1133

1134
1135
1136
1137
1138
		unsigned long flags;
		struct page *page;

		spin_lock_irqsave(&pgd_lock, flags);
		list_for_each_entry(page, &pgd_list, lru) {
Ingo Molnar's avatar
Ingo Molnar committed
1139
			if (!vmalloc_sync_one(page_address(page), address))
1140
				break;
1141
		}
1142
		spin_unlock_irqrestore(&pgd_lock, flags);
1143
1144
	}
#else /* CONFIG_X86_64 */
1145
1146
	for (address = VMALLOC_START & PGDIR_MASK; address <= VMALLOC_END;
	     address += PGDIR_SIZE) {
Ingo Molnar's avatar
Ingo Molnar committed
1147

1148
1149
1150
1151
1152
1153
		const pgd_t *pgd_ref = pgd_offset_k(address);
		unsigned long flags;
		struct page *page;

		if (pgd_none(*pgd_ref))
			continue;
Ingo Molnar's avatar
Ingo Molnar committed
1154

1155
1156
1157
1158
1159
1160
1161
1162
		spin_lock_irqsave(&pgd_lock, flags);
		list_for_each_entry(page, &pgd_list, lru) {
			pgd_t *pgd;
			pgd = (pgd_t *)page_address(page) + pgd_index(address);
			if (pgd_none(*pgd))
				set_pgd(pgd, *pgd_ref);
			else
				BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
1163
		}
1164