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 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");