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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MTD Oops/Panic logger
4 *
5 * Copyright © 2007 Nokia Corporation. All rights reserved.
6 *
7 * Author: Richard Purdie <rpurdie@openedhand.com>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/console.h>
15#include <linux/vmalloc.h>
16#include <linux/workqueue.h>
17#include <linux/sched.h>
18#include <linux/wait.h>
19#include <linux/delay.h>
20#include <linux/interrupt.h>
21#include <linux/timekeeping.h>
22#include <linux/mtd/mtd.h>
23#include <linux/kmsg_dump.h>
24
25/* Maximum MTD partition size */
26#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
27
28static unsigned long record_size = 4096;
29module_param(record_size, ulong, 0400);
30MODULE_PARM_DESC(record_size,
31 "record size for MTD OOPS pages in bytes (default 4096)");
32
33static char mtddev[80];
34module_param_string(mtddev, mtddev, 80, 0400);
35MODULE_PARM_DESC(mtddev,
36 "name or index number of the MTD device to use");
37
38static int dump_oops = 1;
39module_param(dump_oops, int, 0600);
40MODULE_PARM_DESC(dump_oops,
41 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
42
43#define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00 /* Original */
44#define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00 /* Adds the timestamp */
45
46struct mtdoops_hdr {
47 u32 seq;
48 u32 magic;
49 ktime_t timestamp;
50} __packed;
51
52static struct mtdoops_context {
53 struct kmsg_dumper dump;
54
55 int mtd_index;
56 struct work_struct work_erase;
57 struct work_struct work_write;
58 struct mtd_info *mtd;
59 int oops_pages;
60 int nextpage;
61 int nextcount;
62 unsigned long *oops_page_used;
63
64 unsigned long oops_buf_busy;
65 void *oops_buf;
66} oops_cxt;
67
68static void mark_page_used(struct mtdoops_context *cxt, int page)
69{
70 set_bit(page, cxt->oops_page_used);
71}
72
73static void mark_page_unused(struct mtdoops_context *cxt, int page)
74{
75 clear_bit(page, cxt->oops_page_used);
76}
77
78static int page_is_used(struct mtdoops_context *cxt, int page)
79{
80 return test_bit(page, cxt->oops_page_used);
81}
82
83static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
84{
85 struct mtd_info *mtd = cxt->mtd;
86 u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
87 u32 start_page = start_page_offset / record_size;
88 u32 erase_pages = mtd->erasesize / record_size;
89 struct erase_info erase;
90 int ret;
91 int page;
92
93 erase.addr = offset;
94 erase.len = mtd->erasesize;
95
96 ret = mtd_erase(mtd, &erase);
97 if (ret) {
98 pr_warn("erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
99 (unsigned long long)erase.addr,
100 (unsigned long long)erase.len, mtddev);
101 return ret;
102 }
103
104 /* Mark pages as unused */
105 for (page = start_page; page < start_page + erase_pages; page++)
106 mark_page_unused(cxt, page);
107
108 return 0;
109}
110
111static void mtdoops_erase(struct mtdoops_context *cxt)
112{
113 struct mtd_info *mtd = cxt->mtd;
114 int i = 0, j, ret, mod;
115
116 /* We were unregistered */
117 if (!mtd)
118 return;
119
120 mod = (cxt->nextpage * record_size) % mtd->erasesize;
121 if (mod != 0) {
122 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
123 if (cxt->nextpage >= cxt->oops_pages)
124 cxt->nextpage = 0;
125 }
126
127 while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
128badblock:
129 pr_warn("bad block at %08lx\n",
130 cxt->nextpage * record_size);
131 i++;
132 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
133 if (cxt->nextpage >= cxt->oops_pages)
134 cxt->nextpage = 0;
135 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
136 pr_err("all blocks bad!\n");
137 return;
138 }
139 }
140
141 if (ret < 0) {
142 pr_err("mtd_block_isbad failed, aborting\n");
143 return;
144 }
145
146 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
147 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
148
149 if (ret >= 0) {
150 pr_debug("ready %d, %d\n",
151 cxt->nextpage, cxt->nextcount);
152 return;
153 }
154
155 if (ret == -EIO) {
156 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
157 if (ret < 0 && ret != -EOPNOTSUPP) {
158 pr_err("block_markbad failed, aborting\n");
159 return;
160 }
161 }
162 goto badblock;
163}
164
165/* Scheduled work - when we can't proceed without erasing a block */
166static void mtdoops_workfunc_erase(struct work_struct *work)
167{
168 struct mtdoops_context *cxt =
169 container_of(work, struct mtdoops_context, work_erase);
170 mtdoops_erase(cxt);
171}
172
173static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic)
174{
175 cxt->nextpage++;
176 if (cxt->nextpage >= cxt->oops_pages)
177 cxt->nextpage = 0;
178 cxt->nextcount++;
179 if (cxt->nextcount == 0xffffffff)
180 cxt->nextcount = 0;
181
182 if (page_is_used(cxt, cxt->nextpage)) {
183 pr_debug("not ready %d, %d (erase %s)\n",
184 cxt->nextpage, cxt->nextcount,
185 panic ? "immediately" : "scheduled");
186 if (panic) {
187 /* In case of panic, erase immediately */
188 mtdoops_erase(cxt);
189 } else {
190 /* Otherwise, schedule work to erase it "nicely" */
191 schedule_work(&cxt->work_erase);
192 }
193 } else {
194 pr_debug("ready %d, %d (no erase)\n",
195 cxt->nextpage, cxt->nextcount);
196 }
197}
198
199static void mtdoops_write(struct mtdoops_context *cxt, int panic)
200{
201 struct mtd_info *mtd = cxt->mtd;
202 size_t retlen;
203 struct mtdoops_hdr *hdr;
204 int ret;
205
206 if (test_and_set_bit(0, &cxt->oops_buf_busy))
207 return;
208
209 /* Add mtdoops header to the buffer */
210 hdr = (struct mtdoops_hdr *)cxt->oops_buf;
211 hdr->seq = cxt->nextcount;
212 hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2;
213 hdr->timestamp = ktime_get_real();
214
215 if (panic) {
216 ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
217 record_size, &retlen, cxt->oops_buf);
218 if (ret == -EOPNOTSUPP) {
219 pr_err("Cannot write from panic without panic_write\n");
220 goto out;
221 }
222 } else
223 ret = mtd_write(mtd, cxt->nextpage * record_size,
224 record_size, &retlen, cxt->oops_buf);
225
226 if (retlen != record_size || ret < 0)
227 pr_err("write failure at %ld (%td of %ld written), error %d\n",
228 cxt->nextpage * record_size, retlen, record_size, ret);
229 mark_page_used(cxt, cxt->nextpage);
230 memset(cxt->oops_buf, 0xff, record_size);
231
232 mtdoops_inc_counter(cxt, panic);
233out:
234 clear_bit(0, &cxt->oops_buf_busy);
235}
236
237static void mtdoops_workfunc_write(struct work_struct *work)
238{
239 struct mtdoops_context *cxt =
240 container_of(work, struct mtdoops_context, work_write);
241
242 mtdoops_write(cxt, 0);
243}
244
245static void find_next_position(struct mtdoops_context *cxt)
246{
247 struct mtd_info *mtd = cxt->mtd;
248 struct mtdoops_hdr hdr;
249 int ret, page, maxpos = 0;
250 u32 maxcount = 0xffffffff;
251 size_t retlen;
252
253 for (page = 0; page < cxt->oops_pages; page++) {
254 if (mtd_block_isbad(mtd, page * record_size))
255 continue;
256 /* Assume the page is used */
257 mark_page_used(cxt, page);
258 ret = mtd_read(mtd, page * record_size, sizeof(hdr),
259 &retlen, (u_char *)&hdr);
260 if (retlen != sizeof(hdr) ||
261 (ret < 0 && !mtd_is_bitflip(ret))) {
262 pr_err("read failure at %ld (%zu of %zu read), err %d\n",
263 page * record_size, retlen, sizeof(hdr), ret);
264 continue;
265 }
266
267 if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
268 mark_page_unused(cxt, page);
269 if (hdr.seq == 0xffffffff ||
270 (hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 &&
271 hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2))
272 continue;
273 if (maxcount == 0xffffffff) {
274 maxcount = hdr.seq;
275 maxpos = page;
276 } else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
277 maxcount = hdr.seq;
278 maxpos = page;
279 } else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
280 maxcount = hdr.seq;
281 maxpos = page;
282 } else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
283 && maxcount > 0x80000000) {
284 maxcount = hdr.seq;
285 maxpos = page;
286 }
287 }
288 if (maxcount == 0xffffffff) {
289 cxt->nextpage = cxt->oops_pages - 1;
290 cxt->nextcount = 0;
291 }
292 else {
293 cxt->nextpage = maxpos;
294 cxt->nextcount = maxcount;
295 }
296
297 mtdoops_inc_counter(cxt, 0);
298}
299
300static void mtdoops_do_dump(struct kmsg_dumper *dumper,
301 enum kmsg_dump_reason reason)
302{
303 struct mtdoops_context *cxt = container_of(dumper,
304 struct mtdoops_context, dump);
305 struct kmsg_dump_iter iter;
306
307 /* Only dump oopses if dump_oops is set */
308 if (reason == KMSG_DUMP_OOPS && !dump_oops)
309 return;
310
311 kmsg_dump_rewind(&iter);
312
313 if (test_and_set_bit(0, &cxt->oops_buf_busy))
314 return;
315 kmsg_dump_get_buffer(&iter, true,
316 cxt->oops_buf + sizeof(struct mtdoops_hdr),
317 record_size - sizeof(struct mtdoops_hdr), NULL);
318 clear_bit(0, &cxt->oops_buf_busy);
319
320 if (reason != KMSG_DUMP_OOPS) {
321 /* Panics must be written immediately */
322 mtdoops_write(cxt, 1);
323 } else {
324 /* For other cases, schedule work to write it "nicely" */
325 schedule_work(&cxt->work_write);
326 }
327}
328
329static void mtdoops_notify_add(struct mtd_info *mtd)
330{
331 struct mtdoops_context *cxt = &oops_cxt;
332 u64 mtdoops_pages = div_u64(mtd->size, record_size);
333 int err;
334
335 if (!strcmp(mtd->name, mtddev))
336 cxt->mtd_index = mtd->index;
337
338 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
339 return;
340
341 if (mtd->size < mtd->erasesize * 2) {
342 pr_err("MTD partition %d not big enough for mtdoops\n",
343 mtd->index);
344 return;
345 }
346 if (mtd->erasesize < record_size) {
347 pr_err("eraseblock size of MTD partition %d too small\n",
348 mtd->index);
349 return;
350 }
351 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
352 pr_err("mtd%d is too large (limit is %d MiB)\n",
353 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
354 return;
355 }
356
357 /* oops_page_used is a bit field */
358 cxt->oops_page_used =
359 vmalloc(array_size(sizeof(unsigned long),
360 DIV_ROUND_UP(mtdoops_pages,
361 BITS_PER_LONG)));
362 if (!cxt->oops_page_used) {
363 pr_err("could not allocate page array\n");
364 return;
365 }
366
367 cxt->dump.max_reason = KMSG_DUMP_OOPS;
368 cxt->dump.dump = mtdoops_do_dump;
369 err = kmsg_dump_register(&cxt->dump);
370 if (err) {
371 pr_err("registering kmsg dumper failed, error %d\n", err);
372 vfree(cxt->oops_page_used);
373 cxt->oops_page_used = NULL;
374 return;
375 }
376
377 cxt->mtd = mtd;
378 cxt->oops_pages = (int)mtd->size / record_size;
379 find_next_position(cxt);
380 pr_info("Attached to MTD device %d\n", mtd->index);
381}
382
383static void mtdoops_notify_remove(struct mtd_info *mtd)
384{
385 struct mtdoops_context *cxt = &oops_cxt;
386
387 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
388 return;
389
390 if (kmsg_dump_unregister(&cxt->dump) < 0)
391 pr_warn("could not unregister kmsg_dumper\n");
392
393 cxt->mtd = NULL;
394 flush_work(&cxt->work_erase);
395 flush_work(&cxt->work_write);
396}
397
398
399static struct mtd_notifier mtdoops_notifier = {
400 .add = mtdoops_notify_add,
401 .remove = mtdoops_notify_remove,
402};
403
404static int __init mtdoops_init(void)
405{
406 struct mtdoops_context *cxt = &oops_cxt;
407 int mtd_index;
408 char *endp;
409
410 if (strlen(mtddev) == 0) {
411 pr_err("mtd device (mtddev=name/number) must be supplied\n");
412 return -EINVAL;
413 }
414 if ((record_size & 4095) != 0) {
415 pr_err("record_size must be a multiple of 4096\n");
416 return -EINVAL;
417 }
418 if (record_size < 4096) {
419 pr_err("record_size must be over 4096 bytes\n");
420 return -EINVAL;
421 }
422
423 /* Setup the MTD device to use */
424 cxt->mtd_index = -1;
425 mtd_index = simple_strtoul(mtddev, &endp, 0);
426 if (*endp == '\0')
427 cxt->mtd_index = mtd_index;
428
429 cxt->oops_buf = vmalloc(record_size);
430 if (!cxt->oops_buf)
431 return -ENOMEM;
432 memset(cxt->oops_buf, 0xff, record_size);
433 cxt->oops_buf_busy = 0;
434
435 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
436 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
437
438 register_mtd_user(&mtdoops_notifier);
439 return 0;
440}
441
442static void __exit mtdoops_exit(void)
443{
444 struct mtdoops_context *cxt = &oops_cxt;
445
446 unregister_mtd_user(&mtdoops_notifier);
447 vfree(cxt->oops_buf);
448 vfree(cxt->oops_page_used);
449}
450
451
452module_init(mtdoops_init);
453module_exit(mtdoops_exit);
454
455MODULE_LICENSE("GPL");
456MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
457MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
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 ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
173badblock:
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
210static 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
242static 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
250static 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
303static 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
324static 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
376static 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
392static struct mtd_notifier mtdoops_notifier = {
393 .add = mtdoops_notify_add,
394 .remove = mtdoops_notify_remove,
395};
396
397static 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
436static 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
446module_init(mtdoops_init);
447module_exit(mtdoops_exit);
448
449MODULE_LICENSE("GPL");
450MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
451MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");