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