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