drivers/mtd/mtdoops.c

   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 int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
  88 {
  89         struct mtd_info *mtd = cxt->mtd;
  90         u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
  91         u32 start_page = start_page_offset / record_size;
  92         u32 erase_pages = mtd->erasesize / record_size;
  93         struct erase_info erase;
  94         int ret;
  95         int page;
  96
  97         erase.addr = offset;
  98         erase.len = mtd->erasesize;
  99
 100         ret = mtd_erase(mtd, &erase);
 101         if (ret) {
 102                 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
 103                        (unsigned long long)erase.addr,
 104                        (unsigned long long)erase.len, mtddev);
 105                 return ret;
 106         }
 107
 108         /* Mark pages as unused */
 109         for (page = start_page; page < start_page + erase_pages; page++)
 110                 mark_page_unused(cxt, page);
 111
 112         return 0;
 113 }
 114
 115 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
 116 {
 117         cxt->nextpage++;
 118         if (cxt->nextpage >= cxt->oops_pages)
 119                 cxt->nextpage = 0;
 120         cxt->nextcount++;
 121         if (cxt->nextcount == 0xffffffff)
 122                 cxt->nextcount = 0;
 123
 124         if (page_is_used(cxt, cxt->nextpage)) {
 125                 schedule_work(&cxt->work_erase);
 126                 return;
 127         }
 128
 129         printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
 130                cxt->nextpage, cxt->nextcount);
 131 }
 132
 133 /* Scheduled work - when we can't proceed without erasing a block */
 134 static void mtdoops_workfunc_erase(struct work_struct *work)
 135 {
 136         struct mtdoops_context *cxt =
 137                         container_of(work, struct mtdoops_context, work_erase);
 138         struct mtd_info *mtd = cxt->mtd;
 139         int i = 0, j, ret, mod;
 140
 141         /* We were unregistered */
 142         if (!mtd)
 143                 return;
 144
 145         mod = (cxt->nextpage * record_size) % mtd->erasesize;
 146         if (mod != 0) {
 147                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
 148                 if (cxt->nextpage >= cxt->oops_pages)
 149                         cxt->nextpage = 0;
 150         }
 151
 152         while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
 153 badblock:
 154                 printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
 155                        cxt->nextpage * record_size);
 156                 i++;
 157                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
 158                 if (cxt->nextpage >= cxt->oops_pages)
 159                         cxt->nextpage = 0;
 160                 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
 161                         printk(KERN_ERR "mtdoops: all blocks bad!\n");
 162                         return;
 163                 }
 164         }
 165
 166         if (ret < 0) {
 167                 printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
 168                 return;
 169         }
 170
 171         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
 172                 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
 173
 174         if (ret >= 0) {
 175                 printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
 176                        cxt->nextpage, cxt->nextcount);
 177                 return;
 178         }
 179
 180         if (ret == -EIO) {
 181                 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
 182                 if (ret < 0 && ret != -EOPNOTSUPP) {
 183                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
 184                         return;
 185                 }
 186         }
 187         goto badblock;
 188 }
 189
 190 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 191 {
 192         struct mtd_info *mtd = cxt->mtd;
 193         size_t retlen;
 194         u32 *hdr;
 195         int ret;
 196
 197         /* Add mtdoops header to the buffer */
 198         hdr = cxt->oops_buf;
 199         hdr[0] = cxt->nextcount;
 200         hdr[1] = MTDOOPS_KERNMSG_MAGIC;
 201
 202         if (panic) {
 203                 ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
 204                                       record_size, &retlen, cxt->oops_buf);
 205                 if (ret == -EOPNOTSUPP) {
 206                         printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
 207                         return;
 208                 }
 209         } else
 210                 ret = mtd_write(mtd, cxt->nextpage * record_size,
 211                                 record_size, &retlen, cxt->oops_buf);
 212
 213         if (retlen != record_size || ret < 0)
 214                 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
 215                        cxt->nextpage * record_size, retlen, record_size, ret);
 216         mark_page_used(cxt, cxt->nextpage);
 217         memset(cxt->oops_buf, 0xff, record_size);
 218
 219         mtdoops_inc_counter(cxt);
 220 }
 221
 222 static void mtdoops_workfunc_write(struct work_struct *work)
 223 {
 224         struct mtdoops_context *cxt =
 225                         container_of(work, struct mtdoops_context, work_write);
 226
 227         mtdoops_write(cxt, 0);
 228 }
 229
 230 static void find_next_position(struct mtdoops_context *cxt)
 231 {
 232         struct mtd_info *mtd = cxt->mtd;
 233         int ret, page, maxpos = 0;
 234         u32 count[2], maxcount = 0xffffffff;
 235         size_t retlen;
 236
 237         for (page = 0; page < cxt->oops_pages; page++) {
 238                 if (mtd_block_isbad(mtd, page * record_size))
 239                         continue;
 240                 /* Assume the page is used */
 241                 mark_page_used(cxt, page);
 242                 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
 243                                &retlen, (u_char *)&count[0]);
 244                 if (retlen != MTDOOPS_HEADER_SIZE ||
 245                                 (ret < 0 && !mtd_is_bitflip(ret))) {
 246                         printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
 247                                page * record_size, retlen,
 248                                MTDOOPS_HEADER_SIZE, ret);
 249                         continue;
 250                 }
 251
 252                 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
 253                         mark_page_unused(cxt, page);
 254                 if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC)
 255                         continue;
 256                 if (maxcount == 0xffffffff) {
 257                         maxcount = count[0];
 258                         maxpos = page;
 259                 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
 260                         maxcount = count[0];
 261                         maxpos = page;
 262                 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
 263                         maxcount = count[0];
 264                         maxpos = page;
 265                 } else if (count[0] > maxcount && count[0] > 0xc0000000
 266                                         && maxcount > 0x80000000) {
 267                         maxcount = count[0];
 268                         maxpos = page;
 269                 }
 270         }
 271         if (maxcount == 0xffffffff) {
 272                 cxt->nextpage = cxt->oops_pages - 1;
 273                 cxt->nextcount = 0;
 274         }
 275         else {
 276                 cxt->nextpage = maxpos;
 277                 cxt->nextcount = maxcount;
 278         }
 279
 280         mtdoops_inc_counter(cxt);
 281 }
 282
 283 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
 284                             enum kmsg_dump_reason reason)
 285 {
 286         struct mtdoops_context *cxt = container_of(dumper,
 287                         struct mtdoops_context, dump);
 288
 289         /* Only dump oopses if dump_oops is set */
 290         if (reason == KMSG_DUMP_OOPS && !dump_oops)
 291                 return;
 292
 293         kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
 294                              record_size - MTDOOPS_HEADER_SIZE, NULL);
 295
 296         /* Panics must be written immediately */
 297         if (reason != KMSG_DUMP_OOPS)
 298                 mtdoops_write(cxt, 1);
 299
 300         /* For other cases, schedule work to write it "nicely" */
 301         schedule_work(&cxt->work_write);
 302 }
 303
 304 static void mtdoops_notify_add(struct mtd_info *mtd)
 305 {
 306         struct mtdoops_context *cxt = &oops_cxt;
 307         u64 mtdoops_pages = div_u64(mtd->size, record_size);
 308         int err;
 309
 310         if (!strcmp(mtd->name, mtddev))
 311                 cxt->mtd_index = mtd->index;
 312
 313         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 314                 return;
 315
 316         if (mtd->size < mtd->erasesize * 2) {
 317                 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
 318                        mtd->index);
 319                 return;
 320         }
 321         if (mtd->erasesize < record_size) {
 322                 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
 323                        mtd->index);
 324                 return;
 325         }
 326         if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
 327                 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
 328                        mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
 329                 return;
 330         }
 331
 332         /* oops_page_used is a bit field */
 333         cxt->oops_page_used =
 334                 vmalloc(array_size(sizeof(unsigned long),
 335                                    DIV_ROUND_UP(mtdoops_pages,
 336                                                 BITS_PER_LONG)));
 337         if (!cxt->oops_page_used) {
 338                 printk(KERN_ERR "mtdoops: could not allocate page array\n");
 339                 return;
 340         }
 341
 342         cxt->dump.max_reason = KMSG_DUMP_OOPS;
 343         cxt->dump.dump = mtdoops_do_dump;
 344         err = kmsg_dump_register(&cxt->dump);
 345         if (err) {
 346                 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
 347                 vfree(cxt->oops_page_used);
 348                 cxt->oops_page_used = NULL;
 349                 return;
 350         }
 351
 352         cxt->mtd = mtd;
 353         cxt->oops_pages = (int)mtd->size / record_size;
 354         find_next_position(cxt);
 355         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 356 }
 357
 358 static void mtdoops_notify_remove(struct mtd_info *mtd)
 359 {
 360         struct mtdoops_context *cxt = &oops_cxt;
 361
 362         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 363                 return;
 364
 365         if (kmsg_dump_unregister(&cxt->dump) < 0)
 366                 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
 367
 368         cxt->mtd = NULL;
 369         flush_work(&cxt->work_erase);
 370         flush_work(&cxt->work_write);
 371 }
 372
 373
 374 static struct mtd_notifier mtdoops_notifier = {
 375         .add    = mtdoops_notify_add,
 376         .remove = mtdoops_notify_remove,
 377 };
 378
 379 static int __init mtdoops_init(void)
 380 {
 381         struct mtdoops_context *cxt = &oops_cxt;
 382         int mtd_index;
 383         char *endp;
 384
 385         if (strlen(mtddev) == 0) {
 386                 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
 387                 return -EINVAL;
 388         }
 389         if ((record_size & 4095) != 0) {
 390                 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
 391                 return -EINVAL;
 392         }
 393         if (record_size < 4096) {
 394                 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
 395                 return -EINVAL;
 396         }
 397
 398         /* Setup the MTD device to use */
 399         cxt->mtd_index = -1;
 400         mtd_index = simple_strtoul(mtddev, &endp, 0);
 401         if (*endp == '\0')
 402                 cxt->mtd_index = mtd_index;
 403
 404         cxt->oops_buf = vmalloc(record_size);
 405         if (!cxt->oops_buf) {
 406                 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
 407                 return -ENOMEM;
 408         }
 409         memset(cxt->oops_buf, 0xff, record_size);
 410
 411         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 412         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 413
 414         register_mtd_user(&mtdoops_notifier);
 415         return 0;
 416 }
 417
 418 static void __exit mtdoops_exit(void)
 419 {
 420         struct mtdoops_context *cxt = &oops_cxt;
 421
 422         unregister_mtd_user(&mtdoops_notifier);
 423         vfree(cxt->oops_buf);
 424         vfree(cxt->oops_page_used);
 425 }
 426
 427
 428 module_init(mtdoops_init);
 429 module_exit(mtdoops_exit);
 430
 431 MODULE_LICENSE("GPL");
 432 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 433 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");