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 (mtd->block_isbad) {
 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                 }
 180 badblock:
 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 (mtd->block_markbad && ret == -EIO) {
 203                 ret = mtd->block_markbad(mtd, cxt->nextpage * record_size);
 204                 if (ret < 0) {
 205                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
 206                         return;
 207                 }
 208         }
 209         goto badblock;
 210 }
 211
 212 static 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         else
 228                 ret = mtd->write(mtd, cxt->nextpage * record_size,
 229                                         record_size, &retlen, cxt->oops_buf);
 230
 231         if (retlen != record_size || ret < 0)
 232                 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
 233                        cxt->nextpage * record_size, retlen, record_size, ret);
 234         mark_page_used(cxt, cxt->nextpage);
 235         memset(cxt->oops_buf, 0xff, record_size);
 236
 237         mtdoops_inc_counter(cxt);
 238 }
 239
 240 static void mtdoops_workfunc_write(struct work_struct *work)
 241 {
 242         struct mtdoops_context *cxt =
 243                         container_of(work, struct mtdoops_context, work_write);
 244
 245         mtdoops_write(cxt, 0);
 246 }
 247
 248 static void find_next_position(struct mtdoops_context *cxt)
 249 {
 250         struct mtd_info *mtd = cxt->mtd;
 251         int ret, page, maxpos = 0;
 252         u32 count[2], maxcount = 0xffffffff;
 253         size_t retlen;
 254
 255         for (page = 0; page < cxt->oops_pages; page++) {
 256                 if (mtd->block_isbad &&
 257                     mtd->block_isbad(mtd, page * record_size))
 258                         continue;
 259                 /* Assume the page is used */
 260                 mark_page_used(cxt, page);
 261                 ret = mtd->read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
 262                                 &retlen, (u_char *) &count[0]);
 263                 if (retlen != MTDOOPS_HEADER_SIZE ||
 264                                 (ret < 0 && !mtd_is_bitflip(ret))) {
 265                         printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
 266                                page * record_size, retlen,
 267                                MTDOOPS_HEADER_SIZE, ret);
 268                         continue;
 269                 }
 270
 271                 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
 272                         mark_page_unused(cxt, page);
 273                 if (count[0] == 0xffffffff)
 274                         continue;
 275                 if (maxcount == 0xffffffff) {
 276                         maxcount = count[0];
 277                         maxpos = page;
 278                 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
 279                         maxcount = count[0];
 280                         maxpos = page;
 281                 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
 282                         maxcount = count[0];
 283                         maxpos = page;
 284                 } else if (count[0] > maxcount && count[0] > 0xc0000000
 285                                         && maxcount > 0x80000000) {
 286                         maxcount = count[0];
 287                         maxpos = page;
 288                 }
 289         }
 290         if (maxcount == 0xffffffff) {
 291                 cxt->nextpage = 0;
 292                 cxt->nextcount = 1;
 293                 schedule_work(&cxt->work_erase);
 294                 return;
 295         }
 296
 297         cxt->nextpage = maxpos;
 298         cxt->nextcount = maxcount;
 299
 300         mtdoops_inc_counter(cxt);
 301 }
 302
 303 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
 304                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
 305                 const char *s2, unsigned long l2)
 306 {
 307         struct mtdoops_context *cxt = container_of(dumper,
 308                         struct mtdoops_context, dump);
 309         unsigned long s1_start, s2_start;
 310         unsigned long l1_cpy, l2_cpy;
 311         char *dst;
 312
 313         if (reason != KMSG_DUMP_OOPS &&
 314             reason != KMSG_DUMP_PANIC &&
 315             reason != KMSG_DUMP_KEXEC)
 316                 return;
 317
 318         /* Only dump oopses if dump_oops is set */
 319         if (reason == KMSG_DUMP_OOPS && !dump_oops)
 320                 return;
 321
 322         dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */
 323         l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE);
 324         l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy);
 325
 326         s2_start = l2 - l2_cpy;
 327         s1_start = l1 - l1_cpy;
 328
 329         memcpy(dst, s1 + s1_start, l1_cpy);
 330         memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
 331
 332         /* Panics must be written immediately */
 333         if (reason != KMSG_DUMP_OOPS) {
 334                 if (!cxt->mtd->panic_write)
 335                         printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
 336                 else
 337                         mtdoops_write(cxt, 1);
 338                 return;
 339         }
 340
 341         /* For other cases, schedule work to write it "nicely" */
 342         schedule_work(&cxt->work_write);
 343 }
 344
 345 static void mtdoops_notify_add(struct mtd_info *mtd)
 346 {
 347         struct mtdoops_context *cxt = &oops_cxt;
 348         u64 mtdoops_pages = div_u64(mtd->size, record_size);
 349         int err;
 350
 351         if (!strcmp(mtd->name, mtddev))
 352                 cxt->mtd_index = mtd->index;
 353
 354         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 355                 return;
 356
 357         if (mtd->size < mtd->erasesize * 2) {
 358                 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
 359                        mtd->index);
 360                 return;
 361         }
 362         if (mtd->erasesize < record_size) {
 363                 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
 364                        mtd->index);
 365                 return;
 366         }
 367         if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
 368                 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
 369                        mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
 370                 return;
 371         }
 372
 373         /* oops_page_used is a bit field */
 374         cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
 375                         BITS_PER_LONG) * sizeof(unsigned long));
 376         if (!cxt->oops_page_used) {
 377                 printk(KERN_ERR "mtdoops: could not allocate page array\n");
 378                 return;
 379         }
 380
 381         cxt->dump.dump = mtdoops_do_dump;
 382         err = kmsg_dump_register(&cxt->dump);
 383         if (err) {
 384                 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
 385                 vfree(cxt->oops_page_used);
 386                 cxt->oops_page_used = NULL;
 387                 return;
 388         }
 389
 390         cxt->mtd = mtd;
 391         cxt->oops_pages = (int)mtd->size / record_size;
 392         find_next_position(cxt);
 393         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 394 }
 395
 396 static void mtdoops_notify_remove(struct mtd_info *mtd)
 397 {
 398         struct mtdoops_context *cxt = &oops_cxt;
 399
 400         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 401                 return;
 402
 403         if (kmsg_dump_unregister(&cxt->dump) < 0)
 404                 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
 405
 406         cxt->mtd = NULL;
 407         flush_work_sync(&cxt->work_erase);
 408         flush_work_sync(&cxt->work_write);
 409 }
 410
 411
 412 static struct mtd_notifier mtdoops_notifier = {
 413         .add    = mtdoops_notify_add,
 414         .remove = mtdoops_notify_remove,
 415 };
 416
 417 static int __init mtdoops_init(void)
 418 {
 419         struct mtdoops_context *cxt = &oops_cxt;
 420         int mtd_index;
 421         char *endp;
 422
 423         if (strlen(mtddev) == 0) {
 424                 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
 425                 return -EINVAL;
 426         }
 427         if ((record_size & 4095) != 0) {
 428                 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
 429                 return -EINVAL;
 430         }
 431         if (record_size < 4096) {
 432                 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
 433                 return -EINVAL;
 434         }
 435
 436         /* Setup the MTD device to use */
 437         cxt->mtd_index = -1;
 438         mtd_index = simple_strtoul(mtddev, &endp, 0);
 439         if (*endp == '\0')
 440                 cxt->mtd_index = mtd_index;
 441
 442         cxt->oops_buf = vmalloc(record_size);
 443         if (!cxt->oops_buf) {
 444                 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
 445                 return -ENOMEM;
 446         }
 447         memset(cxt->oops_buf, 0xff, record_size);
 448
 449         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 450         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 451
 452         register_mtd_user(&mtdoops_notifier);
 453         return 0;
 454 }
 455
 456 static void __exit mtdoops_exit(void)
 457 {
 458         struct mtdoops_context *cxt = &oops_cxt;
 459
 460         unregister_mtd_user(&mtdoops_notifier);
 461         vfree(cxt->oops_buf);
 462         vfree(cxt->oops_page_used);
 463 }
 464
 465
 466 module_init(mtdoops_init);
 467 module_exit(mtdoops_exit);
 468
 469 MODULE_LICENSE("GPL");
 470 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 471 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");