aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/misc/lkdtm.c
blob: 49c7a23f02fc554f3232295ed7a80b90b96bdc16 (plain) (blame)
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
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
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
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
/*
 * Kprobe module for testing crash dumps
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2006
 *
 * Author: Ankita Garg <ankita@in.ibm.com>
 *
 * This module induces system failures at predefined crashpoints to
 * evaluate the reliability of crash dumps obtained using different dumping
 * solutions.
 *
 * It is adapted from the Linux Kernel Dump Test Tool by
 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
 *
 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
 *
 * See Documentation/fault-injection/provoke-crashes.txt for instructions
 */

#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/kprobes.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/hrtimer.h>
#include <linux/slab.h>
#include <scsi/scsi_cmnd.h>
#include <linux/debugfs.h>
#include <linux/vmalloc.h>
#include <linux/mman.h>

#ifdef CONFIG_IDE
#include <linux/ide.h>
#endif

/*
 * Make sure our attempts to over run the kernel stack doesn't trigger
 * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
 * recurse past the end of THREAD_SIZE by default.
 */
#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
#define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
#else
#define REC_STACK_SIZE (THREAD_SIZE / 8)
#endif
#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)

#define DEFAULT_COUNT 10
#define EXEC_SIZE 64

enum cname {
	CN_INVALID,
	CN_INT_HARDWARE_ENTRY,
	CN_INT_HW_IRQ_EN,
	CN_INT_TASKLET_ENTRY,
	CN_FS_DEVRW,
	CN_MEM_SWAPOUT,
	CN_TIMERADD,
	CN_SCSI_DISPATCH_CMD,
	CN_IDE_CORE_CP,
	CN_DIRECT,
};

enum ctype {
	CT_NONE,
	CT_PANIC,
	CT_BUG,
	CT_WARNING,
	CT_EXCEPTION,
	CT_LOOP,
	CT_OVERFLOW,
	CT_CORRUPT_STACK,
	CT_UNALIGNED_LOAD_STORE_WRITE,
	CT_OVERWRITE_ALLOCATION,
	CT_WRITE_AFTER_FREE,
	CT_SOFTLOCKUP,
	CT_HARDLOCKUP,
	CT_SPINLOCKUP,
	CT_HUNG_TASK,
	CT_EXEC_DATA,
	CT_EXEC_STACK,
	CT_EXEC_KMALLOC,
	CT_EXEC_VMALLOC,
	CT_EXEC_USERSPACE,
	CT_ACCESS_USERSPACE,
	CT_WRITE_RO,
};

static char* cp_name[] = {
	"INT_HARDWARE_ENTRY",
	"INT_HW_IRQ_EN",
	"INT_TASKLET_ENTRY",
	"FS_DEVRW",
	"MEM_SWAPOUT",
	"TIMERADD",
	"SCSI_DISPATCH_CMD",
	"IDE_CORE_CP",
	"DIRECT",
};

static char* cp_type[] = {
	"PANIC",
	"BUG",
	"WARNING",
	"EXCEPTION",
	"LOOP",
	"OVERFLOW",
	"CORRUPT_STACK",
	"UNALIGNED_LOAD_STORE_WRITE",
	"OVERWRITE_ALLOCATION",
	"WRITE_AFTER_FREE",
	"SOFTLOCKUP",
	"HARDLOCKUP",
	"SPINLOCKUP",
	"HUNG_TASK",
	"EXEC_DATA",
	"EXEC_STACK",
	"EXEC_KMALLOC",
	"EXEC_VMALLOC",
	"EXEC_USERSPACE",
	"ACCESS_USERSPACE",
	"WRITE_RO",
};

static struct jprobe lkdtm;

static int lkdtm_parse_commandline(void);
static void lkdtm_handler(void);

static char* cpoint_name;
static char* cpoint_type;
static int cpoint_count = DEFAULT_COUNT;
static int recur_count = REC_NUM_DEFAULT;

static enum cname cpoint = CN_INVALID;
static enum ctype cptype = CT_NONE;
static int count = DEFAULT_COUNT;
static DEFINE_SPINLOCK(count_lock);
static DEFINE_SPINLOCK(lock_me_up);

static u8 data_area[EXEC_SIZE];

static const unsigned long rodata = 0xAA55AA55;

module_param(recur_count, int, 0644);
MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
module_param(cpoint_name, charp, 0444);
MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
module_param(cpoint_type, charp, 0444);
MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
				"hitting the crash point");
module_param(cpoint_count, int, 0644);
MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
				"crash point is to be hit to trigger action");

static unsigned int jp_do_irq(unsigned int irq)
{
	lkdtm_handler();
	jprobe_return();
	return 0;
}

static irqreturn_t jp_handle_irq_event(unsigned int irq,
				       struct irqaction *action)
{
	lkdtm_handler();
	jprobe_return();
	return 0;
}

static void jp_tasklet_action(struct softirq_action *a)
{
	lkdtm_handler();
	jprobe_return();
}

static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
{
	lkdtm_handler();
	jprobe_return();
}

struct scan_control;

static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
					     struct zone *zone,
					     struct scan_control *sc)
{
	lkdtm_handler();
	jprobe_return();
	return 0;
}

static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
			    const enum hrtimer_mode mode)
{
	lkdtm_handler();
	jprobe_return();
	return 0;
}

static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
{
	lkdtm_handler();
	jprobe_return();
	return 0;
}

#ifdef CONFIG_IDE
static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
			struct block_device *bdev, unsigned int cmd,
			unsigned long arg)
{
	lkdtm_handler();
	jprobe_return();
	return 0;
}
#endif

/* Return the crashpoint number or NONE if the name is invalid */
static enum ctype parse_cp_type(const char *what, size_t count)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
		if (!strcmp(what, cp_type[i]))
			return i + 1;
	}

	return CT_NONE;
}

static const char *cp_type_to_str(enum ctype type)
{
	if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
		return "None";

	return cp_type[type - 1];
}

static const char *cp_name_to_str(enum cname name)
{
	if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
		return "INVALID";

	return cp_name[name - 1];
}


static int lkdtm_parse_commandline(void)
{
	int i;
	unsigned long flags;

	if (cpoint_count < 1 || recur_count < 1)
		return -EINVAL;

	spin_lock_irqsave(&count_lock, flags);
	count = cpoint_count;
	spin_unlock_irqrestore(&count_lock, flags);

	/* No special parameters */
	if (!cpoint_type && !cpoint_name)
		return 0;

	/* Neither or both of these need to be set */
	if (!cpoint_type || !cpoint_name)
		return -EINVAL;

	cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
	if (cptype == CT_NONE)
		return -EINVAL;

	for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
		if (!strcmp(cpoint_name, cp_name[i])) {
			cpoint = i + 1;
			return 0;
		}
	}

	/* Could not find a valid crash point */
	return -EINVAL;
}

static int recursive_loop(int remaining)
{
	char buf[REC_STACK_SIZE];

	/* Make sure compiler does not optimize this away. */
	memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
	if (!remaining)
		return 0;
	else
		return recursive_loop(remaining - 1);
}

static void do_nothing(void)
{
	return;
}

static noinline void corrupt_stack(void)
{
	/* Use default char array length that triggers stack protection. */
	char data[8];

	memset((void *)data, 0, 64);
}

static void execute_location(void *dst)
{
	void (*func)(void) = dst;

	memcpy(dst, do_nothing, EXEC_SIZE);
	func();
}

static void execute_user_location(void *dst)
{
	/* Intentionally crossing kernel/user memory boundary. */
	void (*func)(void) = dst;

	if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
		return;
	func();
}

static void lkdtm_do_action(enum ctype which)
{
	switch (which) {
	case CT_PANIC:
		panic("dumptest");
		break;
	case CT_BUG:
		BUG();
		break;
	case CT_WARNING:
		WARN_ON(1);
		break;
	case CT_EXCEPTION:
		*((int *) 0) = 0;
		break;
	case CT_LOOP:
		for (;;)
			;
		break;
	case CT_OVERFLOW:
		(void) recursive_loop(recur_count);
		break;
	case CT_CORRUPT_STACK:
		corrupt_stack();
		break;
	case CT_UNALIGNED_LOAD_STORE_WRITE: {
		static u8 data[5] __attribute__((aligned(4))) = {1, 2,
				3, 4, 5};
		u32 *p;
		u32 val = 0x12345678;

		p = (u32 *)(data + 1);
		if (*p == 0)
			val = 0x87654321;
		*p = val;
		 break;
	}
	case CT_OVERWRITE_ALLOCATION: {
		size_t len = 1020;
		u32 *data = kmalloc(len, GFP_KERNEL);

		data[1024 / sizeof(u32)] = 0x12345678;
		kfree(data);
		break;
	}
	case CT_WRITE_AFTER_FREE: {
		size_t len = 1024;
		u32 *data = kmalloc(len, GFP_KERNEL);

		kfree(data);
		schedule();
		memset(data, 0x78, len);
		break;
	}
	case CT_SOFTLOCKUP:
		preempt_disable();
		for (;;)
			cpu_relax();
		break;
	case CT_HARDLOCKUP:
		local_irq_disable();
		for (;;)
			cpu_relax();
		break;
	case CT_SPINLOCKUP:
		/* Must be called twice to trigger. */
		spin_lock(&lock_me_up);
		/* Let sparse know we intended to exit holding the lock. */
		__release(&lock_me_up);
		break;
	case CT_HUNG_TASK:
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule();
		break;
	case CT_EXEC_DATA:
		execute_location(data_area);
		break;
	case CT_EXEC_STACK: {
		u8 stack_area[EXEC_SIZE];
		execute_location(stack_area);
		break;
	}
	case CT_EXEC_KMALLOC: {
		u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
		execute_location(kmalloc_area);
		kfree(kmalloc_area);
		break;
	}
	case CT_EXEC_VMALLOC: {
		u32 *vmalloc_area = vmalloc(EXEC_SIZE);
		execute_location(vmalloc_area);
		vfree(vmalloc_area);
		break;
	}
	case CT_EXEC_USERSPACE: {
		unsigned long user_addr;

		user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
				    PROT_READ | PROT_WRITE | PROT_EXEC,
				    MAP_ANONYMOUS | MAP_PRIVATE, 0);
		if (user_addr >= TASK_SIZE) {
			pr_warn("Failed to allocate user memory\n");
			return;
		}
		execute_user_location((void *)user_addr);
		vm_munmap(user_addr, PAGE_SIZE);
		break;
	}
	case CT_ACCESS_USERSPACE: {
		unsigned long user_addr, tmp;
		unsigned long *ptr;

		user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
				    PROT_READ | PROT_WRITE | PROT_EXEC,
				    MAP_ANONYMOUS | MAP_PRIVATE, 0);
		if (user_addr >= TASK_SIZE) {
			pr_warn("Failed to allocate user memory\n");
			return;
		}

		ptr = (unsigned long *)user_addr;
		tmp = *ptr;
		tmp += 0xc0dec0de;
		*ptr = tmp;

		vm_munmap(user_addr, PAGE_SIZE);

		break;
	}
	case CT_WRITE_RO: {
		unsigned long *ptr;

		ptr = (unsigned long *)&rodata;
		*ptr ^= 0xabcd1234;

		break;
	}
	case CT_NONE:
	default:
		break;
	}

}

static void lkdtm_handler(void)
{
	unsigned long flags;
	bool do_it = false;

	spin_lock_irqsave(&count_lock, flags);
	count--;
	printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
			cp_name_to_str(cpoint), cp_type_to_str(cptype), count);

	if (count == 0) {
		do_it = true;
		count = cpoint_count;
	}
	spin_unlock_irqrestore(&count_lock, flags);

	if (do_it)
		lkdtm_do_action(cptype);
}

static int lkdtm_register_cpoint(enum cname which)
{
	int ret;

	cpoint = CN_INVALID;
	if (lkdtm.entry != NULL)
		unregister_jprobe(&lkdtm);

	switch (which) {
	case CN_DIRECT:
		lkdtm_do_action(cptype);
		return 0;
	case CN_INT_HARDWARE_ENTRY:
		lkdtm.kp.symbol_name = "do_IRQ";
		lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
		break;
	case CN_INT_HW_IRQ_EN:
		lkdtm.kp.symbol_name = "handle_IRQ_event";
		lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
		break;
	case CN_INT_TASKLET_ENTRY:
		lkdtm.kp.symbol_name = "tasklet_action";
		lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
		break;
	case CN_FS_DEVRW:
		lkdtm.kp.symbol_name = "ll_rw_block";
		lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
		break;
	case CN_MEM_SWAPOUT:
		lkdtm.kp.symbol_name = "shrink_inactive_list";
		lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
		break;
	case CN_TIMERADD:
		lkdtm.kp.symbol_name = "hrtimer_start";
		lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
		break;
	case CN_SCSI_DISPATCH_CMD:
		lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
		lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
		break;
	case CN_IDE_CORE_CP:
#ifdef CONFIG_IDE
		lkdtm.kp.symbol_name = "generic_ide_ioctl";
		lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
#else
		printk(KERN_INFO "lkdtm: Crash point not available\n");
		return -EINVAL;
#endif
		break;
	default:
		printk(KERN_INFO "lkdtm: Invalid Crash Point\n");
		return -EINVAL;
	}

	cpoint = which;
	if ((ret = register_jprobe(&lkdtm)) < 0) {
		printk(KERN_INFO "lkdtm: Couldn't register jprobe\n");
		cpoint = CN_INVALID;
	}

	return ret;
}

static ssize_t do_register_entry(enum cname which, struct file *f,
		const char __user *user_buf, size_t count, loff_t *off)
{
	char *buf;
	int err;

	if (count >= PAGE_SIZE)
		return -EINVAL;

	buf = (char *)__get_free_page(GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	if (copy_from_user(buf, user_buf, count)) {
		free_page((unsigned long) buf);
		return -EFAULT;
	}
	/* NULL-terminate and remove enter */
	buf[count] = '\0';
	strim(buf);

	cptype = parse_cp_type(buf, count);
	free_page((unsigned long) buf);

	if (cptype == CT_NONE)
		return -EINVAL;

	err = lkdtm_register_cpoint(which);
	if (err < 0)
		return err;

	*off += count;

	return count;
}

/* Generic read callback that just prints out the available crash types */
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
		size_t count, loff_t *off)
{
	char *buf;
	int i, n, out;

	buf = (char *)__get_free_page(GFP_KERNEL);
	if (buf == NULL)
		return -ENOMEM;

	n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
	for (i = 0; i < ARRAY_SIZE(cp_type); i++)
		n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
	buf[n] = '\0';

	out = simple_read_from_buffer(user_buf, count, off,
				      buf, n);
	free_page((unsigned long) buf);

	return out;
}

static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
{
	return 0;
}


static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
}

static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
}

static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
}

static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
}

static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
}

static ssize_t timeradd_entry(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_TIMERADD, f, buf, count, off);
}

static ssize_t scsi_dispatch_cmd_entry(struct file *f,
		const char __user *buf, size_t count, loff_t *off)
{
	return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
}

static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
		size_t count, loff_t *off)
{
	return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
}

/* Special entry to just crash directly. Available without KPROBEs */
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
		size_t count, loff_t *off)
{
	enum ctype type;
	char *buf;

	if (count >= PAGE_SIZE)
		return -EINVAL;
	if (count < 1)
		return -EINVAL;

	buf = (char *)__get_free_page(GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	if (copy_from_user(buf, user_buf, count)) {
		free_page((unsigned long) buf);
		return -EFAULT;
	}
	/* NULL-terminate and remove enter */
	buf[count] = '\0';
	strim(buf);

	type = parse_cp_type(buf, count);
	free_page((unsigned long) buf);
	if (type == CT_NONE)
		return -EINVAL;

	printk(KERN_INFO "lkdtm: Performing direct entry %s\n",
			cp_type_to_str(type));
	lkdtm_do_action(type);
	*off += count;

	return count;
}

struct crash_entry {
	const char *name;
	const struct file_operations fops;
};

static const struct crash_entry crash_entries[] = {
	{"DIRECT", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = direct_entry} },
	{"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = int_hardware_entry} },
	{"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = int_hw_irq_en} },
	{"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = int_tasklet_entry} },
	{"FS_DEVRW", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = fs_devrw_entry} },
	{"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = mem_swapout_entry} },
	{"TIMERADD", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = timeradd_entry} },
	{"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = scsi_dispatch_cmd_entry} },
	{"IDE_CORE_CP",	{.read = lkdtm_debugfs_read,
			.llseek = generic_file_llseek,
			.open = lkdtm_debugfs_open,
			.write = ide_core_cp_entry} },
};

static struct dentry *lkdtm_debugfs_root;

static int __init lkdtm_module_init(void)
{
	int ret = -EINVAL;
	int n_debugfs_entries = 1; /* Assume only the direct entry */
	int i;

	/* Register debugfs interface */
	lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
	if (!lkdtm_debugfs_root) {
		printk(KERN_ERR "lkdtm: creating root dir failed\n");
		return -ENODEV;
	}

#ifdef CONFIG_KPROBES
	n_debugfs_entries = ARRAY_SIZE(crash_entries);
#endif

	for (i = 0; i < n_debugfs_entries; i++) {
		const struct crash_entry *cur = &crash_entries[i];
		struct dentry *de;

		de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
				NULL, &cur->fops);
		if (de == NULL) {
			printk(KERN_ERR "lkdtm: could not create %s\n",
					cur->name);
			goto out_err;
		}
	}

	if (lkdtm_parse_commandline() == -EINVAL) {
		printk(KERN_INFO "lkdtm: Invalid command\n");
		goto out_err;
	}

	if (cpoint != CN_INVALID && cptype != CT_NONE) {
		ret = lkdtm_register_cpoint(cpoint);
		if (ret < 0) {
			printk(KERN_INFO "lkdtm: Invalid crash point %d\n",
					cpoint);
			goto out_err;
		}
		printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n",
				cpoint_name, cpoint_type);
	} else {
		printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n");
	}

	return 0;

out_err:
	debugfs_remove_recursive(lkdtm_debugfs_root);
	return ret;
}

static void __exit lkdtm_module_exit(void)
{
	debugfs_remove_recursive(lkdtm_debugfs_root);

	unregister_jprobe(&lkdtm);
	printk(KERN_INFO "lkdtm: Crash point unregistered\n");
}

module_init(lkdtm_module_init);
module_exit(lkdtm_module_exit);

MODULE_LICENSE("GPL");