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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
42static unsigned long record_size = 4096;
43module_param(record_size, ulong, 0400);
44MODULE_PARM_DESC(record_size,
45 "record size for MTD OOPS pages in bytes (default 4096)");
46
47static char mtddev[80];
48module_param_string(mtddev, mtddev, 80, 0400);
49MODULE_PARM_DESC(mtddev,
50 "name or index number of the MTD device to use");
51
52static int dump_oops = 1;
53module_param(dump_oops, int, 0600);
54MODULE_PARM_DESC(dump_oops,
55 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
56
57static 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
72static void mark_page_used(struct mtdoops_context *cxt, int page)
73{
74 set_bit(page, cxt->oops_page_used);
75}
76
77static void mark_page_unused(struct mtdoops_context *cxt, int page)
78{
79 clear_bit(page, cxt->oops_page_used);
80}
81
82static int page_is_used(struct mtdoops_context *cxt, int page)
83{
84 return test_bit(page, cxt->oops_page_used);
85}
86
87static 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
93static 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
135static 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 */
154static 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 (1) {
173 ret = mtd_block_isbad(mtd, cxt->nextpage * record_size);
174 if (!ret)
175 break;
176 if (ret < 0) {
177 printk(KERN_ERR "mtdoops: block_isbad failed, aborting\n");
178 return;
179 }
180badblock:
181 printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
182 cxt->nextpage * record_size);
183 i++;
184 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
185 if (cxt->nextpage >= cxt->oops_pages)
186 cxt->nextpage = 0;
187 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
188 printk(KERN_ERR "mtdoops: all blocks bad!\n");
189 return;
190 }
191 }
192
193 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
194 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
195
196 if (ret >= 0) {
197 printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
198 cxt->nextpage, cxt->nextcount);
199 return;
200 }
201
202 if (ret == -EIO) {
203 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
204 if (ret < 0 && ret != -EOPNOTSUPP) {
205 printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
206 return;
207 }
208 }
209 goto badblock;
210}
211
212static void mtdoops_write(struct mtdoops_context *cxt, int panic)
213{
214 struct mtd_info *mtd = cxt->mtd;
215 size_t retlen;
216 u32 *hdr;
217 int ret;
218
219 /* Add mtdoops header to the buffer */
220 hdr = cxt->oops_buf;
221 hdr[0] = cxt->nextcount;
222 hdr[1] = MTDOOPS_KERNMSG_MAGIC;
223
224 if (panic) {
225 ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
226 record_size, &retlen, cxt->oops_buf);
227 if (ret == -EOPNOTSUPP) {
228 printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
229 return;
230 }
231 } else
232 ret = mtd_write(mtd, cxt->nextpage * record_size,
233 record_size, &retlen, cxt->oops_buf);
234
235 if (retlen != record_size || ret < 0)
236 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
237 cxt->nextpage * record_size, retlen, record_size, ret);
238 mark_page_used(cxt, cxt->nextpage);
239 memset(cxt->oops_buf, 0xff, record_size);
240
241 mtdoops_inc_counter(cxt);
242}
243
244static void mtdoops_workfunc_write(struct work_struct *work)
245{
246 struct mtdoops_context *cxt =
247 container_of(work, struct mtdoops_context, work_write);
248
249 mtdoops_write(cxt, 0);
250}
251
252static void find_next_position(struct mtdoops_context *cxt)
253{
254 struct mtd_info *mtd = cxt->mtd;
255 int ret, page, maxpos = 0;
256 u32 count[2], maxcount = 0xffffffff;
257 size_t retlen;
258
259 for (page = 0; page < cxt->oops_pages; page++) {
260 if (mtd_block_isbad(mtd, page * record_size))
261 continue;
262 /* Assume the page is used */
263 mark_page_used(cxt, page);
264 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
265 &retlen, (u_char *)&count[0]);
266 if (retlen != MTDOOPS_HEADER_SIZE ||
267 (ret < 0 && !mtd_is_bitflip(ret))) {
268 printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
269 page * record_size, retlen,
270 MTDOOPS_HEADER_SIZE, ret);
271 continue;
272 }
273
274 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
275 mark_page_unused(cxt, page);
276 if (count[0] == 0xffffffff)
277 continue;
278 if (maxcount == 0xffffffff) {
279 maxcount = count[0];
280 maxpos = page;
281 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
282 maxcount = count[0];
283 maxpos = page;
284 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
285 maxcount = count[0];
286 maxpos = page;
287 } else if (count[0] > maxcount && count[0] > 0xc0000000
288 && maxcount > 0x80000000) {
289 maxcount = count[0];
290 maxpos = page;
291 }
292 }
293 if (maxcount == 0xffffffff) {
294 cxt->nextpage = 0;
295 cxt->nextcount = 1;
296 schedule_work(&cxt->work_erase);
297 return;
298 }
299
300 cxt->nextpage = maxpos;
301 cxt->nextcount = maxcount;
302
303 mtdoops_inc_counter(cxt);
304}
305
306static void mtdoops_do_dump(struct kmsg_dumper *dumper,
307 enum kmsg_dump_reason reason)
308{
309 struct mtdoops_context *cxt = container_of(dumper,
310 struct mtdoops_context, dump);
311
312 /* Only dump oopses if dump_oops is set */
313 if (reason == KMSG_DUMP_OOPS && !dump_oops)
314 return;
315
316 kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
317 record_size - MTDOOPS_HEADER_SIZE, NULL);
318
319 /* Panics must be written immediately */
320 if (reason != KMSG_DUMP_OOPS)
321 mtdoops_write(cxt, 1);
322
323 /* For other cases, schedule work to write it "nicely" */
324 schedule_work(&cxt->work_write);
325}
326
327static void mtdoops_notify_add(struct mtd_info *mtd)
328{
329 struct mtdoops_context *cxt = &oops_cxt;
330 u64 mtdoops_pages = div_u64(mtd->size, record_size);
331 int err;
332
333 if (!strcmp(mtd->name, mtddev))
334 cxt->mtd_index = mtd->index;
335
336 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
337 return;
338
339 if (mtd->size < mtd->erasesize * 2) {
340 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
341 mtd->index);
342 return;
343 }
344 if (mtd->erasesize < record_size) {
345 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
346 mtd->index);
347 return;
348 }
349 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
350 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
351 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
352 return;
353 }
354
355 /* oops_page_used is a bit field */
356 cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
357 BITS_PER_LONG) * sizeof(unsigned long));
358 if (!cxt->oops_page_used) {
359 printk(KERN_ERR "mtdoops: could not allocate page array\n");
360 return;
361 }
362
363 cxt->dump.max_reason = KMSG_DUMP_OOPS;
364 cxt->dump.dump = mtdoops_do_dump;
365 err = kmsg_dump_register(&cxt->dump);
366 if (err) {
367 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
368 vfree(cxt->oops_page_used);
369 cxt->oops_page_used = NULL;
370 return;
371 }
372
373 cxt->mtd = mtd;
374 cxt->oops_pages = (int)mtd->size / record_size;
375 find_next_position(cxt);
376 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
377}
378
379static void mtdoops_notify_remove(struct mtd_info *mtd)
380{
381 struct mtdoops_context *cxt = &oops_cxt;
382
383 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
384 return;
385
386 if (kmsg_dump_unregister(&cxt->dump) < 0)
387 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
388
389 cxt->mtd = NULL;
390 flush_work_sync(&cxt->work_erase);
391 flush_work_sync(&cxt->work_write);
392}
393
394
395static struct mtd_notifier mtdoops_notifier = {
396 .add = mtdoops_notify_add,
397 .remove = mtdoops_notify_remove,
398};
399
400static int __init mtdoops_init(void)
401{
402 struct mtdoops_context *cxt = &oops_cxt;
403 int mtd_index;
404 char *endp;
405
406 if (strlen(mtddev) == 0) {
407 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
408 return -EINVAL;
409 }
410 if ((record_size & 4095) != 0) {
411 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
412 return -EINVAL;
413 }
414 if (record_size < 4096) {
415 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
416 return -EINVAL;
417 }
418
419 /* Setup the MTD device to use */
420 cxt->mtd_index = -1;
421 mtd_index = simple_strtoul(mtddev, &endp, 0);
422 if (*endp == '\0')
423 cxt->mtd_index = mtd_index;
424
425 cxt->oops_buf = vmalloc(record_size);
426 if (!cxt->oops_buf) {
427 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
428 return -ENOMEM;
429 }
430 memset(cxt->oops_buf, 0xff, record_size);
431
432 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
433 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
434
435 register_mtd_user(&mtdoops_notifier);
436 return 0;
437}
438
439static void __exit mtdoops_exit(void)
440{
441 struct mtdoops_context *cxt = &oops_cxt;
442
443 unregister_mtd_user(&mtdoops_notifier);
444 vfree(cxt->oops_buf);
445 vfree(cxt->oops_page_used);
446}
447
448
449module_init(mtdoops_init);
450module_exit(mtdoops_exit);
451
452MODULE_LICENSE("GPL");
453MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
454MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");