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 ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
 173badblock:
 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
 210static 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
 242static 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
 250static 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)
 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 = 0;
 293                cxt->nextcount = 1;
 294                schedule_work(&cxt->work_erase);
 295                return;
 296        }
 297
 298        cxt->nextpage = maxpos;
 299        cxt->nextcount = maxcount;
 300
 301        mtdoops_inc_counter(cxt);
 302}
 303
 304static void mtdoops_do_dump(struct kmsg_dumper *dumper,
 305                            enum kmsg_dump_reason reason)
 306{
 307        struct mtdoops_context *cxt = container_of(dumper,
 308                        struct mtdoops_context, dump);
 309
 310        /* Only dump oopses if dump_oops is set */
 311        if (reason == KMSG_DUMP_OOPS && !dump_oops)
 312                return;
 313
 314        kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
 315                             record_size - MTDOOPS_HEADER_SIZE, NULL);
 316
 317        /* Panics must be written immediately */
 318        if (reason != KMSG_DUMP_OOPS)
 319                mtdoops_write(cxt, 1);
 320
 321        /* For other cases, schedule work to write it "nicely" */
 322        schedule_work(&cxt->work_write);
 323}
 324
 325static void mtdoops_notify_add(struct mtd_info *mtd)
 326{
 327        struct mtdoops_context *cxt = &oops_cxt;
 328        u64 mtdoops_pages = div_u64(mtd->size, record_size);
 329        int err;
 330
 331        if (!strcmp(mtd->name, mtddev))
 332                cxt->mtd_index = mtd->index;
 333
 334        if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 335                return;
 336
 337        if (mtd->size < mtd->erasesize * 2) {
 338                printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
 339                       mtd->index);
 340                return;
 341        }
 342        if (mtd->erasesize < record_size) {
 343                printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
 344                       mtd->index);
 345                return;
 346        }
 347        if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
 348                printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
 349                       mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
 350                return;
 351        }
 352
 353        /* oops_page_used is a bit field */
 354        cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
 355                        BITS_PER_LONG) * sizeof(unsigned long));
 356        if (!cxt->oops_page_used) {
 357                printk(KERN_ERR "mtdoops: could not allocate page array\n");
 358                return;
 359        }
 360
 361        cxt->dump.max_reason = KMSG_DUMP_OOPS;
 362        cxt->dump.dump = mtdoops_do_dump;
 363        err = kmsg_dump_register(&cxt->dump);
 364        if (err) {
 365                printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
 366                vfree(cxt->oops_page_used);
 367                cxt->oops_page_used = NULL;
 368                return;
 369        }
 370
 371        cxt->mtd = mtd;
 372        cxt->oops_pages = (int)mtd->size / record_size;
 373        find_next_position(cxt);
 374        printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 375}
 376
 377static void mtdoops_notify_remove(struct mtd_info *mtd)
 378{
 379        struct mtdoops_context *cxt = &oops_cxt;
 380
 381        if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
 382                return;
 383
 384        if (kmsg_dump_unregister(&cxt->dump) < 0)
 385                printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
 386
 387        cxt->mtd = NULL;
 388        flush_work(&cxt->work_erase);
 389        flush_work(&cxt->work_write);
 390}
 391
 392
 393static struct mtd_notifier mtdoops_notifier = {
 394        .add    = mtdoops_notify_add,
 395        .remove = mtdoops_notify_remove,
 396};
 397
 398static int __init mtdoops_init(void)
 399{
 400        struct mtdoops_context *cxt = &oops_cxt;
 401        int mtd_index;
 402        char *endp;
 403
 404        if (strlen(mtddev) == 0) {
 405                printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
 406                return -EINVAL;
 407        }
 408        if ((record_size & 4095) != 0) {
 409                printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
 410                return -EINVAL;
 411        }
 412        if (record_size < 4096) {
 413                printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
 414                return -EINVAL;
 415        }
 416
 417        /* Setup the MTD device to use */
 418        cxt->mtd_index = -1;
 419        mtd_index = simple_strtoul(mtddev, &endp, 0);
 420        if (*endp == '\0')
 421                cxt->mtd_index = mtd_index;
 422
 423        cxt->oops_buf = vmalloc(record_size);
 424        if (!cxt->oops_buf) {
 425                printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
 426                return -ENOMEM;
 427        }
 428        memset(cxt->oops_buf, 0xff, record_size);
 429
 430        INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
 431        INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
 432
 433        register_mtd_user(&mtdoops_notifier);
 434        return 0;
 435}
 436
 437static void __exit mtdoops_exit(void)
 438{
 439        struct mtdoops_context *cxt = &oops_cxt;
 440
 441        unregister_mtd_user(&mtdoops_notifier);
 442        vfree(cxt->oops_buf);
 443        vfree(cxt->oops_page_used);
 444}
 445
 446
 447module_init(mtdoops_init);
 448module_exit(mtdoops_exit);
 449
 450MODULE_LICENSE("GPL");
 451MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 452MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
 453
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