drivers/misc/apanic.c

   1 /* drivers/misc/apanic.c
   2  *
   3  * Copyright (C) 2009 Google, Inc.
   4  * Author: San Mehat <san@android.com>
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/errno.h>
  21 #include <linux/init.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/device.h>
  24 #include <linux/types.h>
  25 #include <linux/delay.h>
  26 #include <linux/sched.h>
  27 #include <linux/wait.h>
  28 #include <linux/wakelock.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/mtd/mtd.h>
  32 #include <linux/notifier.h>
  33 #include <linux/mtd/mtd.h>
  34 #include <linux/debugfs.h>
  35 #include <linux/fs.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/mutex.h>
  38 #include <linux/workqueue.h>
  39 #include <linux/preempt.h>
  40
  41 extern void ram_console_enable_console(int);
  42
  43 struct panic_header {
  44         u32 magic;
  45 #define PANIC_MAGIC 0xdeadf00d
  46
  47         u32 version;
  48 #define PHDR_VERSION   0x01
  49
  50         u32 console_offset;
  51         u32 console_length;
  52
  53         u32 threads_offset;
  54         u32 threads_length;
  55 };
  56
  57 struct apanic_data {
  58         struct mtd_info         *mtd;
  59         struct panic_header     curr;
  60         void                    *bounce;
  61         struct proc_dir_entry   *apanic_console;
  62         struct proc_dir_entry   *apanic_threads;
  63 };
  64
  65 static struct apanic_data drv_ctx;
  66 static struct work_struct proc_removal_work;
  67 static DEFINE_MUTEX(drv_mutex);
  68
  69 static unsigned int *apanic_bbt;
  70 static unsigned int apanic_erase_blocks;
  71 static unsigned int apanic_good_blocks;
  72
  73 static void set_bb(unsigned int block, unsigned int *bbt)
  74 {
  75         unsigned int flag = 1;
  76
  77         BUG_ON(block >= apanic_erase_blocks);
  78
  79         flag = flag << (block%32);
  80         apanic_bbt[block/32] |= flag;
  81         apanic_good_blocks--;
  82 }
  83
  84 static unsigned int get_bb(unsigned int block, unsigned int *bbt)
  85 {
  86         unsigned int flag;
  87
  88         BUG_ON(block >= apanic_erase_blocks);
  89
  90         flag = 1 << (block%32);
  91         return apanic_bbt[block/32] & flag;
  92 }
  93
  94 static void alloc_bbt(struct mtd_info *mtd, unsigned int *bbt)
  95 {
  96         int bbt_size;
  97         apanic_erase_blocks = (mtd->size)>>(mtd->erasesize_shift);
  98         bbt_size = (apanic_erase_blocks+32)/32;
  99
 100         apanic_bbt = kmalloc(bbt_size*4, GFP_KERNEL);
 101         memset(apanic_bbt, 0, bbt_size*4);
 102         apanic_good_blocks = apanic_erase_blocks;
 103 }
 104 static void scan_bbt(struct mtd_info *mtd, unsigned int *bbt)
 105 {
 106         int i;
 107
 108         for (i = 0; i < apanic_erase_blocks; i++) {
 109                 if (mtd->block_isbad(mtd, i*mtd->erasesize))
 110                         set_bb(i, apanic_bbt);
 111         }
 112 }
 113
 114 #define APANIC_INVALID_OFFSET 0xFFFFFFFF
 115
 116 static unsigned int phy_offset(struct mtd_info *mtd, unsigned int offset)
 117 {
 118         unsigned int logic_block = offset>>(mtd->erasesize_shift);
 119         unsigned int phy_block;
 120         unsigned good_block = 0;
 121
 122         for (phy_block = 0; phy_block < apanic_erase_blocks; phy_block++) {
 123                 if (!get_bb(phy_block, apanic_bbt))
 124                         good_block++;
 125                 if (good_block == (logic_block + 1))
 126                         break;
 127         }
 128
 129         if (good_block != (logic_block + 1))
 130                 return APANIC_INVALID_OFFSET;
 131
 132         return offset + ((phy_block-logic_block)<<mtd->erasesize_shift);
 133 }
 134
 135 static void apanic_erase_callback(struct erase_info *done)
 136 {
 137         wait_queue_head_t *wait_q = (wait_queue_head_t *) done->priv;
 138         wake_up(wait_q);
 139 }
 140
 141 static int apanic_proc_read(char *buffer, char **start, off_t offset,
 142                                int count, int *peof, void *dat)
 143 {
 144         struct apanic_data *ctx = &drv_ctx;
 145         size_t file_length;
 146         off_t file_offset;
 147         unsigned int page_no;
 148         off_t page_offset;
 149         int rc;
 150         size_t len;
 151
 152         if (!count)
 153                 return 0;
 154
 155         mutex_lock(&drv_mutex);
 156
 157         switch ((int) dat) {
 158         case 1: /* apanic_console */
 159                 file_length = ctx->curr.console_length;
 160                 file_offset = ctx->curr.console_offset;
 161                 break;
 162         case 2: /* apanic_threads */
 163                 file_length = ctx->curr.threads_length;
 164                 file_offset = ctx->curr.threads_offset;
 165                 break;
 166         default:
 167                 pr_err("Bad dat (%d)\n", (int) dat);
 168                 mutex_unlock(&drv_mutex);
 169                 return -EINVAL;
 170         }
 171
 172         if ((offset + count) > file_length) {
 173                 mutex_unlock(&drv_mutex);
 174                 return 0;
 175         }
 176
 177         /* We only support reading a maximum of a flash page */
 178         if (count > ctx->mtd->writesize)
 179                 count = ctx->mtd->writesize;
 180
 181         page_no = (file_offset + offset) / ctx->mtd->writesize;
 182         page_offset = (file_offset + offset) % ctx->mtd->writesize;
 183
 184
 185         if (phy_offset(ctx->mtd, (page_no * ctx->mtd->writesize))
 186                 == APANIC_INVALID_OFFSET) {
 187                 pr_err("apanic: reading an invalid address\n");
 188                 mutex_unlock(&drv_mutex);
 189                 return -EINVAL;
 190         }
 191         rc = ctx->mtd->read(ctx->mtd,
 192                 phy_offset(ctx->mtd, (page_no * ctx->mtd->writesize)),
 193                 ctx->mtd->writesize,
 194                 &len, ctx->bounce);
 195
 196         if (page_offset)
 197                 count -= page_offset;
 198         memcpy(buffer, ctx->bounce + page_offset, count);
 199
 200         *start = count;
 201
 202         if ((offset + count) == file_length)
 203                 *peof = 1;
 204
 205         mutex_unlock(&drv_mutex);
 206         return count;
 207 }
 208
 209 static void mtd_panic_erase(void)
 210 {
 211         struct apanic_data *ctx = &drv_ctx;
 212         struct erase_info erase;
 213         DECLARE_WAITQUEUE(wait, current);
 214         wait_queue_head_t wait_q;
 215         int rc, i;
 216
 217         init_waitqueue_head(&wait_q);
 218         erase.mtd = ctx->mtd;
 219         erase.callback = apanic_erase_callback;
 220         erase.len = ctx->mtd->erasesize;
 221         erase.priv = (u_long)&wait_q;
 222         for (i = 0; i < ctx->mtd->size; i += ctx->mtd->erasesize) {
 223                 erase.addr = i;
 224                 set_current_state(TASK_INTERRUPTIBLE);
 225                 add_wait_queue(&wait_q, &wait);
 226
 227                 if (get_bb(erase.addr>>ctx->mtd->erasesize_shift, apanic_bbt)) {
 228                         printk(KERN_WARNING
 229                                "apanic: Skipping erase of bad "
 230                                "block @%llx\n", erase.addr);
 231                         set_current_state(TASK_RUNNING);
 232                         remove_wait_queue(&wait_q, &wait);
 233                         continue;
 234                 }
 235
 236                 rc = ctx->mtd->erase(ctx->mtd, &erase);
 237                 if (rc) {
 238                         set_current_state(TASK_RUNNING);
 239                         remove_wait_queue(&wait_q, &wait);
 240                         printk(KERN_ERR
 241                                "apanic: Erase of 0x%llx, 0x%llx failed\n",
 242                                (unsigned long long) erase.addr,
 243                                (unsigned long long) erase.len);
 244                         if (rc == -EIO) {
 245                                 if (ctx->mtd->block_markbad(ctx->mtd,
 246                                                             erase.addr)) {
 247                                         printk(KERN_ERR
 248                                                "apanic: Err marking blk bad\n");
 249                                         goto out;
 250                                 }
 251                                 printk(KERN_INFO
 252                                        "apanic: Marked a bad block"
 253                                        " @%llx\n", erase.addr);
 254                                 set_bb(erase.addr>>ctx->mtd->erasesize_shift,
 255                                         apanic_bbt);
 256                                 continue;
 257                         }
 258                         goto out;
 259                 }
 260                 schedule();
 261                 remove_wait_queue(&wait_q, &wait);
 262         }
 263         printk(KERN_DEBUG "apanic: %s partition erased\n",
 264                CONFIG_APANIC_PLABEL);
 265 out:
 266         return;
 267 }
 268
 269 static void apanic_remove_proc_work(struct work_struct *work)
 270 {
 271         struct apanic_data *ctx = &drv_ctx;
 272
 273         mutex_lock(&drv_mutex);
 274         mtd_panic_erase();
 275         memset(&ctx->curr, 0, sizeof(struct panic_header));
 276         if (ctx->apanic_console) {
 277                 remove_proc_entry("apanic_console", NULL);
 278                 ctx->apanic_console = NULL;
 279         }
 280         if (ctx->apanic_threads) {
 281                 remove_proc_entry("apanic_threads", NULL);
 282                 ctx->apanic_threads = NULL;
 283         }
 284         mutex_unlock(&drv_mutex);
 285 }
 286
 287 static int apanic_proc_write(struct file *file, const char __user *buffer,
 288                                 unsigned long count, void *data)
 289 {
 290         schedule_work(&proc_removal_work);
 291         return count;
 292 }
 293
 294 static void mtd_panic_notify_add(struct mtd_info *mtd)
 295 {
 296         struct apanic_data *ctx = &drv_ctx;
 297         struct panic_header *hdr = ctx->bounce;
 298         size_t len;
 299         int rc;
 300         int    proc_entry_created = 0;
 301
 302         if (strcmp(mtd->name, CONFIG_APANIC_PLABEL))
 303                 return;
 304
 305         ctx->mtd = mtd;
 306
 307         alloc_bbt(mtd, apanic_bbt);
 308         scan_bbt(mtd, apanic_bbt);
 309
 310         if (apanic_good_blocks == 0) {
 311                 printk(KERN_ERR "apanic: no any good blocks?!\n");
 312                 goto out_err;
 313         }
 314
 315         rc = mtd->read(mtd, phy_offset(mtd, 0), mtd->writesize,
 316                         &len, ctx->bounce);
 317         if (rc && rc == -EBADMSG) {
 318                 printk(KERN_WARNING
 319                        "apanic: Bad ECC on block 0 (ignored)\n");
 320         } else if (rc && rc != -EUCLEAN) {
 321                 printk(KERN_ERR "apanic: Error reading block 0 (%d)\n", rc);
 322                 goto out_err;
 323         }
 324
 325         if (len != mtd->writesize) {
 326                 printk(KERN_ERR "apanic: Bad read size (%d)\n", rc);
 327                 goto out_err;
 328         }
 329
 330         printk(KERN_INFO "apanic: Bound to mtd partition '%s'\n", mtd->name);
 331
 332         if (hdr->magic != PANIC_MAGIC) {
 333                 printk(KERN_INFO "apanic: No panic data available\n");
 334                 mtd_panic_erase();
 335                 return;
 336         }
 337
 338         if (hdr->version != PHDR_VERSION) {
 339                 printk(KERN_INFO "apanic: Version mismatch (%d != %d)\n",
 340                        hdr->version, PHDR_VERSION);
 341                 mtd_panic_erase();
 342                 return;
 343         }
 344
 345         memcpy(&ctx->curr, hdr, sizeof(struct panic_header));
 346
 347         printk(KERN_INFO "apanic: c(%u, %u) t(%u, %u)\n",
 348                hdr->console_offset, hdr->console_length,
 349                hdr->threads_offset, hdr->threads_length);
 350
 351         if (hdr->console_length) {
 352                 ctx->apanic_console = create_proc_entry("apanic_console",
 353                                                       S_IFREG | S_IRUGO, NULL);
 354                 if (!ctx->apanic_console)
 355                         printk(KERN_ERR "%s: failed creating procfile\n",
 356                                __func__);
 357                 else {
 358                         ctx->apanic_console->read_proc = apanic_proc_read;
 359                         ctx->apanic_console->write_proc = apanic_proc_write;
 360                         ctx->apanic_console->size = hdr->console_length;
 361                         ctx->apanic_console->data = (void *) 1;
 362                         proc_entry_created = 1;
 363                 }
 364         }
 365
 366         if (hdr->threads_length) {
 367                 ctx->apanic_threads = create_proc_entry("apanic_threads",
 368                                                        S_IFREG | S_IRUGO, NULL);
 369                 if (!ctx->apanic_threads)
 370                         printk(KERN_ERR "%s: failed creating procfile\n",
 371                                __func__);
 372                 else {
 373                         ctx->apanic_threads->read_proc = apanic_proc_read;
 374                         ctx->apanic_threads->write_proc = apanic_proc_write;
 375                         ctx->apanic_threads->size = hdr->threads_length;
 376                         ctx->apanic_threads->data = (void *) 2;
 377                         proc_entry_created = 1;
 378                 }
 379         }
 380
 381         if (!proc_entry_created)
 382                 mtd_panic_erase();
 383
 384         return;
 385 out_err:
 386         ctx->mtd = NULL;
 387 }
 388
 389 static void mtd_panic_notify_remove(struct mtd_info *mtd)
 390 {
 391         struct apanic_data *ctx = &drv_ctx;
 392         if (mtd == ctx->mtd) {
 393                 ctx->mtd = NULL;
 394                 printk(KERN_INFO "apanic: Unbound from %s\n", mtd->name);
 395         }
 396 }
 397
 398 static struct mtd_notifier mtd_panic_notifier = {
 399         .add    = mtd_panic_notify_add,
 400         .remove = mtd_panic_notify_remove,
 401 };
 402
 403 static int in_panic = 0;
 404
 405 static int apanic_writeflashpage(struct mtd_info *mtd, loff_t to,
 406                                  const u_char *buf)
 407 {
 408         int rc;
 409         size_t wlen;
 410         int panic = in_interrupt() | in_atomic();
 411
 412         if (panic && !mtd->panic_write) {
 413                 printk(KERN_EMERG "%s: No panic_write available\n", __func__);
 414                 return 0;
 415         } else if (!panic && !mtd->write) {
 416                 printk(KERN_EMERG "%s: No write available\n", __func__);
 417                 return 0;
 418         }
 419
 420         to = phy_offset(mtd, to);
 421         if (to == APANIC_INVALID_OFFSET) {
 422                 printk(KERN_EMERG "apanic: write to invalid address\n");
 423                 return 0;
 424         }
 425
 426         if (panic)
 427                 rc = mtd->panic_write(mtd, to, mtd->writesize, &wlen, buf);
 428         else
 429                 rc = mtd->write(mtd, to, mtd->writesize, &wlen, buf);
 430
 431         if (rc) {
 432                 printk(KERN_EMERG
 433                        "%s: Error writing data to flash (%d)\n",
 434                        __func__, rc);
 435                 return rc;
 436         }
 437
 438         return wlen;
 439 }
 440
 441 extern int log_buf_copy(char *dest, int idx, int len);
 442 extern void log_buf_clear(void);
 443
 444 /*
 445  * Writes the contents of the console to the specified offset in flash.
 446  * Returns number of bytes written
 447  */
 448 static int apanic_write_console(struct mtd_info *mtd, unsigned int off)
 449 {
 450         struct apanic_data *ctx = &drv_ctx;
 451         int saved_oip;
 452         int idx = 0;
 453         int rc, rc2;
 454         unsigned int last_chunk = 0;
 455
 456         while (!last_chunk) {
 457                 saved_oip = oops_in_progress;
 458                 oops_in_progress = 1;
 459                 rc = log_buf_copy(ctx->bounce, idx, mtd->writesize);
 460                 if (rc < 0)
 461                         break;
 462
 463                 if (rc != mtd->writesize)
 464                         last_chunk = rc;
 465
 466                 oops_in_progress = saved_oip;
 467                 if (rc <= 0)
 468                         break;
 469                 if (rc != mtd->writesize)
 470                         memset(ctx->bounce + rc, 0, mtd->writesize - rc);
 471
 472                 rc2 = apanic_writeflashpage(mtd, off, ctx->bounce);
 473                 if (rc2 <= 0) {
 474                         printk(KERN_EMERG
 475                                "apanic: Flash write failed (%d)\n", rc2);
 476                         return idx;
 477                 }
 478                 if (!last_chunk)
 479                         idx += rc2;
 480                 else
 481                         idx += last_chunk;
 482                 off += rc2;
 483         }
 484         return idx;
 485 }
 486
 487 static int apanic(struct notifier_block *this, unsigned long event,
 488                         void *ptr)
 489 {
 490         struct apanic_data *ctx = &drv_ctx;
 491         struct panic_header *hdr = (struct panic_header *) ctx->bounce;
 492         int console_offset = 0;
 493         int console_len = 0;
 494         int threads_offset = 0;
 495         int threads_len = 0;
 496         int rc;
 497
 498         if (in_panic)
 499                 return NOTIFY_DONE;
 500         in_panic = 1;
 501 #ifdef CONFIG_PREEMPT
 502         /* Ensure that cond_resched() won't try to preempt anybody */
 503         add_preempt_count(PREEMPT_ACTIVE);
 504 #endif
 505         touch_softlockup_watchdog();
 506
 507         if (!ctx->mtd)
 508                 goto out;
 509
 510         if (ctx->curr.magic) {
 511                 printk(KERN_EMERG "Crash partition in use!\n");
 512                 goto out;
 513         }
 514         console_offset = ctx->mtd->writesize;
 515
 516         /*
 517          * Write out the console
 518          */
 519         console_len = apanic_write_console(ctx->mtd, console_offset);
 520         if (console_len < 0) {
 521                 printk(KERN_EMERG "Error writing console to panic log! (%d)\n",
 522                        console_len);
 523                 console_len = 0;
 524         }
 525
 526         /*
 527          * Write out all threads
 528          */
 529         threads_offset = ALIGN(console_offset + console_len,
 530                                ctx->mtd->writesize);
 531         if (!threads_offset)
 532                 threads_offset = ctx->mtd->writesize;
 533
 534         ram_console_enable_console(0);
 535
 536         log_buf_clear();
 537         show_state_filter(0);
 538         threads_len = apanic_write_console(ctx->mtd, threads_offset);
 539         if (threads_len < 0) {
 540                 printk(KERN_EMERG "Error writing threads to panic log! (%d)\n",
 541                        threads_len);
 542                 threads_len = 0;
 543         }
 544
 545         /*
 546          * Finally write the panic header
 547          */
 548         memset(ctx->bounce, 0, PAGE_SIZE);
 549         hdr->magic = PANIC_MAGIC;
 550         hdr->version = PHDR_VERSION;
 551
 552         hdr->console_offset = console_offset;
 553         hdr->console_length = console_len;
 554
 555         hdr->threads_offset = threads_offset;
 556         hdr->threads_length = threads_len;
 557
 558         rc = apanic_writeflashpage(ctx->mtd, 0, ctx->bounce);
 559         if (rc <= 0) {
 560                 printk(KERN_EMERG "apanic: Header write failed (%d)\n",
 561                        rc);
 562                 goto out;
 563         }
 564
 565         printk(KERN_EMERG "apanic: Panic dump sucessfully written to flash\n");
 566
 567  out:
 568 #ifdef CONFIG_PREEMPT
 569         sub_preempt_count(PREEMPT_ACTIVE);
 570 #endif
 571         in_panic = 0;
 572         return NOTIFY_DONE;
 573 }
 574
 575 static struct notifier_block panic_blk = {
 576         .notifier_call  = apanic,
 577 };
 578
 579 static int panic_dbg_get(void *data, u64 *val)
 580 {
 581         apanic(NULL, 0, NULL);
 582         return 0;
 583 }
 584
 585 static int panic_dbg_set(void *data, u64 val)
 586 {
 587         BUG();
 588         return -1;
 589 }
 590
 591 DEFINE_SIMPLE_ATTRIBUTE(panic_dbg_fops, panic_dbg_get, panic_dbg_set, "%llu\n");
 592
 593 int __init apanic_init(void)
 594 {
 595         register_mtd_user(&mtd_panic_notifier);
 596         atomic_notifier_chain_register(&panic_notifier_list, &panic_blk);
 597         debugfs_create_file("apanic", 0644, NULL, NULL, &panic_dbg_fops);
 598         memset(&drv_ctx, 0, sizeof(drv_ctx));
 599         drv_ctx.bounce = (void *) __get_free_page(GFP_KERNEL);
 600         INIT_WORK(&proc_removal_work, apanic_remove_proc_work);
 601         printk(KERN_INFO "Android kernel panic handler initialized (bind=%s)\n",
 602                CONFIG_APANIC_PLABEL);
 603         return 0;
 604 }
 605
 606 module_init(apanic_init);