xref: /openbmc/linux/drivers/mtd/mtdoops.c (revision 82e6fdd6)
1 /*
2  * MTD Oops/Panic logger
3  *
4  * Copyright © 2007 Nokia Corporation. All rights reserved.
5  *
6  * Author: Richard Purdie <rpurdie@openedhand.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * version 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20  * 02110-1301 USA
21  *
22  */
23 
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/console.h>
27 #include <linux/vmalloc.h>
28 #include <linux/workqueue.h>
29 #include <linux/sched.h>
30 #include <linux/wait.h>
31 #include <linux/delay.h>
32 #include <linux/interrupt.h>
33 #include <linux/mtd/mtd.h>
34 #include <linux/kmsg_dump.h>
35 
36 /* Maximum MTD partition size */
37 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
38 
39 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
40 #define MTDOOPS_HEADER_SIZE   8
41 
42 static unsigned long record_size = 4096;
43 module_param(record_size, ulong, 0400);
44 MODULE_PARM_DESC(record_size,
45 		"record size for MTD OOPS pages in bytes (default 4096)");
46 
47 static char mtddev[80];
48 module_param_string(mtddev, mtddev, 80, 0400);
49 MODULE_PARM_DESC(mtddev,
50 		"name or index number of the MTD device to use");
51 
52 static int dump_oops = 1;
53 module_param(dump_oops, int, 0600);
54 MODULE_PARM_DESC(dump_oops,
55 		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
56 
57 static struct mtdoops_context {
58 	struct kmsg_dumper dump;
59 
60 	int mtd_index;
61 	struct work_struct work_erase;
62 	struct work_struct work_write;
63 	struct mtd_info *mtd;
64 	int oops_pages;
65 	int nextpage;
66 	int nextcount;
67 	unsigned long *oops_page_used;
68 
69 	void *oops_buf;
70 } oops_cxt;
71 
72 static void mark_page_used(struct mtdoops_context *cxt, int page)
73 {
74 	set_bit(page, cxt->oops_page_used);
75 }
76 
77 static void mark_page_unused(struct mtdoops_context *cxt, int page)
78 {
79 	clear_bit(page, cxt->oops_page_used);
80 }
81 
82 static int page_is_used(struct mtdoops_context *cxt, int page)
83 {
84 	return test_bit(page, cxt->oops_page_used);
85 }
86 
87 static void mtdoops_erase_callback(struct erase_info *done)
88 {
89 	wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
90 	wake_up(wait_q);
91 }
92 
93 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
94 {
95 	struct mtd_info *mtd = cxt->mtd;
96 	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
97 	u32 start_page = start_page_offset / record_size;
98 	u32 erase_pages = mtd->erasesize / record_size;
99 	struct erase_info erase;
100 	DECLARE_WAITQUEUE(wait, current);
101 	wait_queue_head_t wait_q;
102 	int ret;
103 	int page;
104 
105 	init_waitqueue_head(&wait_q);
106 	erase.mtd = mtd;
107 	erase.callback = mtdoops_erase_callback;
108 	erase.addr = offset;
109 	erase.len = mtd->erasesize;
110 	erase.priv = (u_long)&wait_q;
111 
112 	set_current_state(TASK_INTERRUPTIBLE);
113 	add_wait_queue(&wait_q, &wait);
114 
115 	ret = mtd_erase(mtd, &erase);
116 	if (ret) {
117 		set_current_state(TASK_RUNNING);
118 		remove_wait_queue(&wait_q, &wait);
119 		printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
120 		       (unsigned long long)erase.addr,
121 		       (unsigned long long)erase.len, mtddev);
122 		return ret;
123 	}
124 
125 	schedule();  /* Wait for erase to finish. */
126 	remove_wait_queue(&wait_q, &wait);
127 
128 	/* Mark pages as unused */
129 	for (page = start_page; page < start_page + erase_pages; page++)
130 		mark_page_unused(cxt, page);
131 
132 	return 0;
133 }
134 
135 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
136 {
137 	cxt->nextpage++;
138 	if (cxt->nextpage >= cxt->oops_pages)
139 		cxt->nextpage = 0;
140 	cxt->nextcount++;
141 	if (cxt->nextcount == 0xffffffff)
142 		cxt->nextcount = 0;
143 
144 	if (page_is_used(cxt, cxt->nextpage)) {
145 		schedule_work(&cxt->work_erase);
146 		return;
147 	}
148 
149 	printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
150 	       cxt->nextpage, cxt->nextcount);
151 }
152 
153 /* Scheduled work - when we can't proceed without erasing a block */
154 static void mtdoops_workfunc_erase(struct work_struct *work)
155 {
156 	struct mtdoops_context *cxt =
157 			container_of(work, struct mtdoops_context, work_erase);
158 	struct mtd_info *mtd = cxt->mtd;
159 	int i = 0, j, ret, mod;
160 
161 	/* We were unregistered */
162 	if (!mtd)
163 		return;
164 
165 	mod = (cxt->nextpage * record_size) % mtd->erasesize;
166 	if (mod != 0) {
167 		cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
168 		if (cxt->nextpage >= cxt->oops_pages)
169 			cxt->nextpage = 0;
170 	}
171 
172 	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
173 badblock:
174 		printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
175 		       cxt->nextpage * record_size);
176 		i++;
177 		cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
178 		if (cxt->nextpage >= cxt->oops_pages)
179 			cxt->nextpage = 0;
180 		if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
181 			printk(KERN_ERR "mtdoops: all blocks bad!\n");
182 			return;
183 		}
184 	}
185 
186 	if (ret < 0) {
187 		printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
188 		return;
189 	}
190 
191 	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
192 		ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
193 
194 	if (ret >= 0) {
195 		printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
196 		       cxt->nextpage, cxt->nextcount);
197 		return;
198 	}
199 
200 	if (ret == -EIO) {
201 		ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
202 		if (ret < 0 && ret != -EOPNOTSUPP) {
203 			printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
204 			return;
205 		}
206 	}
207 	goto badblock;
208 }
209 
210 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
211 {
212 	struct mtd_info *mtd = cxt->mtd;
213 	size_t retlen;
214 	u32 *hdr;
215 	int ret;
216 
217 	/* Add mtdoops header to the buffer */
218 	hdr = cxt->oops_buf;
219 	hdr[0] = cxt->nextcount;
220 	hdr[1] = MTDOOPS_KERNMSG_MAGIC;
221 
222 	if (panic) {
223 		ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
224 				      record_size, &retlen, cxt->oops_buf);
225 		if (ret == -EOPNOTSUPP) {
226 			printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
227 			return;
228 		}
229 	} else
230 		ret = mtd_write(mtd, cxt->nextpage * record_size,
231 				record_size, &retlen, cxt->oops_buf);
232 
233 	if (retlen != record_size || ret < 0)
234 		printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
235 		       cxt->nextpage * record_size, retlen, record_size, ret);
236 	mark_page_used(cxt, cxt->nextpage);
237 	memset(cxt->oops_buf, 0xff, record_size);
238 
239 	mtdoops_inc_counter(cxt);
240 }
241 
242 static void mtdoops_workfunc_write(struct work_struct *work)
243 {
244 	struct mtdoops_context *cxt =
245 			container_of(work, struct mtdoops_context, work_write);
246 
247 	mtdoops_write(cxt, 0);
248 }
249 
250 static void find_next_position(struct mtdoops_context *cxt)
251 {
252 	struct mtd_info *mtd = cxt->mtd;
253 	int ret, page, maxpos = 0;
254 	u32 count[2], maxcount = 0xffffffff;
255 	size_t retlen;
256 
257 	for (page = 0; page < cxt->oops_pages; page++) {
258 		if (mtd_block_isbad(mtd, page * record_size))
259 			continue;
260 		/* Assume the page is used */
261 		mark_page_used(cxt, page);
262 		ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
263 			       &retlen, (u_char *)&count[0]);
264 		if (retlen != MTDOOPS_HEADER_SIZE ||
265 				(ret < 0 && !mtd_is_bitflip(ret))) {
266 			printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
267 			       page * record_size, retlen,
268 			       MTDOOPS_HEADER_SIZE, ret);
269 			continue;
270 		}
271 
272 		if (count[0] == 0xffffffff && count[1] == 0xffffffff)
273 			mark_page_unused(cxt, page);
274 		if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC)
275 			continue;
276 		if (maxcount == 0xffffffff) {
277 			maxcount = count[0];
278 			maxpos = page;
279 		} else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
280 			maxcount = count[0];
281 			maxpos = page;
282 		} else if (count[0] > maxcount && count[0] < 0xc0000000) {
283 			maxcount = count[0];
284 			maxpos = page;
285 		} else if (count[0] > maxcount && count[0] > 0xc0000000
286 					&& maxcount > 0x80000000) {
287 			maxcount = count[0];
288 			maxpos = page;
289 		}
290 	}
291 	if (maxcount == 0xffffffff) {
292 		cxt->nextpage = cxt->oops_pages - 1;
293 		cxt->nextcount = 0;
294 	}
295 	else {
296 		cxt->nextpage = maxpos;
297 		cxt->nextcount = maxcount;
298 	}
299 
300 	mtdoops_inc_counter(cxt);
301 }
302 
303 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
304 			    enum kmsg_dump_reason reason)
305 {
306 	struct mtdoops_context *cxt = container_of(dumper,
307 			struct mtdoops_context, dump);
308 
309 	/* Only dump oopses if dump_oops is set */
310 	if (reason == KMSG_DUMP_OOPS && !dump_oops)
311 		return;
312 
313 	kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
314 			     record_size - MTDOOPS_HEADER_SIZE, NULL);
315 
316 	/* Panics must be written immediately */
317 	if (reason != KMSG_DUMP_OOPS)
318 		mtdoops_write(cxt, 1);
319 
320 	/* For other cases, schedule work to write it "nicely" */
321 	schedule_work(&cxt->work_write);
322 }
323 
324 static void mtdoops_notify_add(struct mtd_info *mtd)
325 {
326 	struct mtdoops_context *cxt = &oops_cxt;
327 	u64 mtdoops_pages = div_u64(mtd->size, record_size);
328 	int err;
329 
330 	if (!strcmp(mtd->name, mtddev))
331 		cxt->mtd_index = mtd->index;
332 
333 	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
334 		return;
335 
336 	if (mtd->size < mtd->erasesize * 2) {
337 		printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
338 		       mtd->index);
339 		return;
340 	}
341 	if (mtd->erasesize < record_size) {
342 		printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
343 		       mtd->index);
344 		return;
345 	}
346 	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
347 		printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
348 		       mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
349 		return;
350 	}
351 
352 	/* oops_page_used is a bit field */
353 	cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
354 			BITS_PER_LONG) * sizeof(unsigned long));
355 	if (!cxt->oops_page_used) {
356 		printk(KERN_ERR "mtdoops: could not allocate page array\n");
357 		return;
358 	}
359 
360 	cxt->dump.max_reason = KMSG_DUMP_OOPS;
361 	cxt->dump.dump = mtdoops_do_dump;
362 	err = kmsg_dump_register(&cxt->dump);
363 	if (err) {
364 		printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
365 		vfree(cxt->oops_page_used);
366 		cxt->oops_page_used = NULL;
367 		return;
368 	}
369 
370 	cxt->mtd = mtd;
371 	cxt->oops_pages = (int)mtd->size / record_size;
372 	find_next_position(cxt);
373 	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
374 }
375 
376 static void mtdoops_notify_remove(struct mtd_info *mtd)
377 {
378 	struct mtdoops_context *cxt = &oops_cxt;
379 
380 	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
381 		return;
382 
383 	if (kmsg_dump_unregister(&cxt->dump) < 0)
384 		printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
385 
386 	cxt->mtd = NULL;
387 	flush_work(&cxt->work_erase);
388 	flush_work(&cxt->work_write);
389 }
390 
391 
392 static struct mtd_notifier mtdoops_notifier = {
393 	.add	= mtdoops_notify_add,
394 	.remove	= mtdoops_notify_remove,
395 };
396 
397 static int __init mtdoops_init(void)
398 {
399 	struct mtdoops_context *cxt = &oops_cxt;
400 	int mtd_index;
401 	char *endp;
402 
403 	if (strlen(mtddev) == 0) {
404 		printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
405 		return -EINVAL;
406 	}
407 	if ((record_size & 4095) != 0) {
408 		printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
409 		return -EINVAL;
410 	}
411 	if (record_size < 4096) {
412 		printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
413 		return -EINVAL;
414 	}
415 
416 	/* Setup the MTD device to use */
417 	cxt->mtd_index = -1;
418 	mtd_index = simple_strtoul(mtddev, &endp, 0);
419 	if (*endp == '\0')
420 		cxt->mtd_index = mtd_index;
421 
422 	cxt->oops_buf = vmalloc(record_size);
423 	if (!cxt->oops_buf) {
424 		printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
425 		return -ENOMEM;
426 	}
427 	memset(cxt->oops_buf, 0xff, record_size);
428 
429 	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
430 	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
431 
432 	register_mtd_user(&mtdoops_notifier);
433 	return 0;
434 }
435 
436 static void __exit mtdoops_exit(void)
437 {
438 	struct mtdoops_context *cxt = &oops_cxt;
439 
440 	unregister_mtd_user(&mtdoops_notifier);
441 	vfree(cxt->oops_buf);
442 	vfree(cxt->oops_page_used);
443 }
444 
445 
446 module_init(mtdoops_init);
447 module_exit(mtdoops_exit);
448 
449 MODULE_LICENSE("GPL");
450 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
451 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
452