summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/mtdoops.c
blob: 2f11585b5613eeb24c0a15bbbc7e4caea3ca22e5 (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
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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * MTD Oops/Panic logger
 *
 * Copyright © 2007 Nokia Corporation. All rights reserved.
 *
 * Author: Richard Purdie <rpurdie@openedhand.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/timekeeping.h>
#include <linux/mtd/mtd.h>
#include <linux/kmsg_dump.h>

/* Maximum MTD partition size */
#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)

static unsigned long record_size = 4096;
module_param(record_size, ulong, 0400);
MODULE_PARM_DESC(record_size,
		"record size for MTD OOPS pages in bytes (default 4096)");

static char mtddev[80];
module_param_string(mtddev, mtddev, 80, 0400);
MODULE_PARM_DESC(mtddev,
		"name or index number of the MTD device to use");

static int dump_oops = 1;
module_param(dump_oops, int, 0600);
MODULE_PARM_DESC(dump_oops,
		"set to 1 to dump oopses, 0 to only dump panics (default 1)");

#define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00  /* Original */
#define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00  /* Adds the timestamp */

struct mtdoops_hdr {
	u32 seq;
	u32 magic;
	ktime_t timestamp;
} __packed;

static struct mtdoops_context {
	struct kmsg_dumper dump;

	int mtd_index;
	struct work_struct work_erase;
	struct work_struct work_write;
	struct mtd_info *mtd;
	int oops_pages;
	int nextpage;
	int nextcount;
	unsigned long *oops_page_used;

	unsigned long oops_buf_busy;
	void *oops_buf;
} oops_cxt;

static void mark_page_used(struct mtdoops_context *cxt, int page)
{
	set_bit(page, cxt->oops_page_used);
}

static void mark_page_unused(struct mtdoops_context *cxt, int page)
{
	clear_bit(page, cxt->oops_page_used);
}

static int page_is_used(struct mtdoops_context *cxt, int page)
{
	return test_bit(page, cxt->oops_page_used);
}

static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
{
	struct mtd_info *mtd = cxt->mtd;
	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
	u32 start_page = start_page_offset / record_size;
	u32 erase_pages = mtd->erasesize / record_size;
	struct erase_info erase;
	int ret;
	int page;

	erase.addr = offset;
	erase.len = mtd->erasesize;

	ret = mtd_erase(mtd, &erase);
	if (ret) {
		pr_warn("erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
			(unsigned long long)erase.addr,
			(unsigned long long)erase.len, mtddev);
		return ret;
	}

	/* Mark pages as unused */
	for (page = start_page; page < start_page + erase_pages; page++)
		mark_page_unused(cxt, page);

	return 0;
}

static void mtdoops_erase(struct mtdoops_context *cxt)
{
	struct mtd_info *mtd = cxt->mtd;
	int i = 0, j, ret, mod;

	/* We were unregistered */
	if (!mtd)
		return;

	mod = (cxt->nextpage * record_size) % mtd->erasesize;
	if (mod != 0) {
		cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
		if (cxt->nextpage >= cxt->oops_pages)
			cxt->nextpage = 0;
	}

	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
badblock:
		pr_warn("bad block at %08lx\n",
			cxt->nextpage * record_size);
		i++;
		cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
		if (cxt->nextpage >= cxt->oops_pages)
			cxt->nextpage = 0;
		if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
			pr_err("all blocks bad!\n");
			return;
		}
	}

	if (ret < 0) {
		pr_err("mtd_block_isbad failed, aborting\n");
		return;
	}

	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
		ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);

	if (ret >= 0) {
		pr_debug("ready %d, %d\n",
			 cxt->nextpage, cxt->nextcount);
		return;
	}

	if (ret == -EIO) {
		ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
		if (ret < 0 && ret != -EOPNOTSUPP) {
			pr_err("block_markbad failed, aborting\n");
			return;
		}
	}
	goto badblock;
}

/* Scheduled work - when we can't proceed without erasing a block */
static void mtdoops_workfunc_erase(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_erase);
	mtdoops_erase(cxt);
}

static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic)
{
	cxt->nextpage++;
	if (cxt->nextpage >= cxt->oops_pages)
		cxt->nextpage = 0;
	cxt->nextcount++;
	if (cxt->nextcount == 0xffffffff)
		cxt->nextcount = 0;

	if (page_is_used(cxt, cxt->nextpage)) {
		pr_debug("not ready %d, %d (erase %s)\n",
			 cxt->nextpage, cxt->nextcount,
			 panic ? "immediately" : "scheduled");
		if (panic) {
			/* In case of panic, erase immediately */
			mtdoops_erase(cxt);
		} else {
			/* Otherwise, schedule work to erase it "nicely" */
			schedule_work(&cxt->work_erase);
		}
	} else {
		pr_debug("ready %d, %d (no erase)\n",
			 cxt->nextpage, cxt->nextcount);
	}
}

static void mtdoops_write(struct mtdoops_context *cxt, int panic)
{
	struct mtd_info *mtd = cxt->mtd;
	size_t retlen;
	struct mtdoops_hdr *hdr;
	int ret;

	if (test_and_set_bit(0, &cxt->oops_buf_busy))
		return;

	/* Add mtdoops header to the buffer */
	hdr = (struct mtdoops_hdr *)cxt->oops_buf;
	hdr->seq = cxt->nextcount;
	hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2;
	hdr->timestamp = ktime_get_real();

	if (panic) {
		ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
				      record_size, &retlen, cxt->oops_buf);
		if (ret == -EOPNOTSUPP) {
			pr_err("Cannot write from panic without panic_write\n");
			goto out;
		}
	} else
		ret = mtd_write(mtd, cxt->nextpage * record_size,
				record_size, &retlen, cxt->oops_buf);

	if (retlen != record_size || ret < 0)
		pr_err("write failure at %ld (%td of %ld written), error %d\n",
		       cxt->nextpage * record_size, retlen, record_size, ret);
	mark_page_used(cxt, cxt->nextpage);
	memset(cxt->oops_buf, 0xff, record_size);

	mtdoops_inc_counter(cxt, panic);
out:
	clear_bit(0, &cxt->oops_buf_busy);
}

static void mtdoops_workfunc_write(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_write);

	mtdoops_write(cxt, 0);
}

static void find_next_position(struct mtdoops_context *cxt)
{
	struct mtd_info *mtd = cxt->mtd;
	struct mtdoops_hdr hdr;
	int ret, page, maxpos = 0;
	u32 maxcount = 0xffffffff;
	size_t retlen;

	for (page = 0; page < cxt->oops_pages; page++) {
		if (mtd_block_isbad(mtd, page * record_size))
			continue;
		/* Assume the page is used */
		mark_page_used(cxt, page);
		ret = mtd_read(mtd, page * record_size, sizeof(hdr),
			       &retlen, (u_char *)&hdr);
		if (retlen != sizeof(hdr) ||
				(ret < 0 && !mtd_is_bitflip(ret))) {
			pr_err("read failure at %ld (%zu of %zu read), err %d\n",
			       page * record_size, retlen, sizeof(hdr), ret);
			continue;
		}

		if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
			mark_page_unused(cxt, page);
		if (hdr.seq == 0xffffffff ||
		    (hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 &&
		     hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2))
			continue;
		if (maxcount == 0xffffffff) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
					&& maxcount > 0x80000000) {
			maxcount = hdr.seq;
			maxpos = page;
		}
	}
	if (maxcount == 0xffffffff) {
		cxt->nextpage = cxt->oops_pages - 1;
		cxt->nextcount = 0;
	}
	else {
		cxt->nextpage = maxpos;
		cxt->nextcount = maxcount;
	}

	mtdoops_inc_counter(cxt, 0);
}

static void mtdoops_do_dump(struct kmsg_dumper *dumper,
			    enum kmsg_dump_reason reason)
{
	struct mtdoops_context *cxt = container_of(dumper,
			struct mtdoops_context, dump);
	struct kmsg_dump_iter iter;

	/* Only dump oopses if dump_oops is set */
	if (reason == KMSG_DUMP_OOPS && !dump_oops)
		return;

	kmsg_dump_rewind(&iter);

	if (test_and_set_bit(0, &cxt->oops_buf_busy))
		return;
	kmsg_dump_get_buffer(&iter, true,
			     cxt->oops_buf + sizeof(struct mtdoops_hdr),
			     record_size - sizeof(struct mtdoops_hdr), NULL);
	clear_bit(0, &cxt->oops_buf_busy);

	if (reason != KMSG_DUMP_OOPS) {
		/* Panics must be written immediately */
		mtdoops_write(cxt, 1);
	} else {
		/* For other cases, schedule work to write it "nicely" */
		schedule_work(&cxt->work_write);
	}
}

static void mtdoops_notify_add(struct mtd_info *mtd)
{
	struct mtdoops_context *cxt = &oops_cxt;
	u64 mtdoops_pages = div_u64(mtd->size, record_size);
	int err;

	if (!strcmp(mtd->name, mtddev))
		cxt->mtd_index = mtd->index;

	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
		return;

	if (mtd->size < mtd->erasesize * 2) {
		pr_err("MTD partition %d not big enough for mtdoops\n",
		       mtd->index);
		return;
	}
	if (mtd->erasesize < record_size) {
		pr_err("eraseblock size of MTD partition %d too small\n",
		       mtd->index);
		return;
	}
	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
		pr_err("mtd%d is too large (limit is %d MiB)\n",
		       mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
		return;
	}

	/* oops_page_used is a bit field */
	cxt->oops_page_used =
		vmalloc(array_size(sizeof(unsigned long),
				   DIV_ROUND_UP(mtdoops_pages,
						BITS_PER_LONG)));
	if (!cxt->oops_page_used) {
		pr_err("could not allocate page array\n");
		return;
	}

	cxt->dump.max_reason = KMSG_DUMP_OOPS;
	cxt->dump.dump = mtdoops_do_dump;
	err = kmsg_dump_register(&cxt->dump);
	if (err) {
		pr_err("registering kmsg dumper failed, error %d\n", err);
		vfree(cxt->oops_page_used);
		cxt->oops_page_used = NULL;
		return;
	}

	cxt->mtd = mtd;
	cxt->oops_pages = (int)mtd->size / record_size;
	find_next_position(cxt);
	pr_info("Attached to MTD device %d\n", mtd->index);
}

static void mtdoops_notify_remove(struct mtd_info *mtd)
{
	struct mtdoops_context *cxt = &oops_cxt;

	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
		return;

	if (kmsg_dump_unregister(&cxt->dump) < 0)
		pr_warn("could not unregister kmsg_dumper\n");

	cxt->mtd = NULL;
	flush_work(&cxt->work_erase);
	flush_work(&cxt->work_write);
}


static struct mtd_notifier mtdoops_notifier = {
	.add	= mtdoops_notify_add,
	.remove	= mtdoops_notify_remove,
};

static int __init mtdoops_init(void)
{
	struct mtdoops_context *cxt = &oops_cxt;
	int mtd_index;
	char *endp;

	if (strlen(mtddev) == 0) {
		pr_err("mtd device (mtddev=name/number) must be supplied\n");
		return -EINVAL;
	}
	if ((record_size & 4095) != 0) {
		pr_err("record_size must be a multiple of 4096\n");
		return -EINVAL;
	}
	if (record_size < 4096) {
		pr_err("record_size must be over 4096 bytes\n");
		return -EINVAL;
	}

	/* Setup the MTD device to use */
	cxt->mtd_index = -1;
	mtd_index = simple_strtoul(mtddev, &endp, 0);
	if (*endp == '\0')
		cxt->mtd_index = mtd_index;

	cxt->oops_buf = vmalloc(record_size);
	if (!cxt->oops_buf)
		return -ENOMEM;
	memset(cxt->oops_buf, 0xff, record_size);
	cxt->oops_buf_busy = 0;

	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);

	register_mtd_user(&mtdoops_notifier);
	return 0;
}

static void __exit mtdoops_exit(void)
{
	struct mtdoops_context *cxt = &oops_cxt;

	unregister_mtd_user(&mtdoops_notifier);
	vfree(cxt->oops_buf);
	vfree(cxt->oops_page_used);
}


module_init(mtdoops_init);
module_exit(mtdoops_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");