fs/pstore/platform.c

   1 /*
   2  * Persistent Storage - platform driver interface parts.
   3  *
   4  * Copyright (C) 2007-2008 Google, Inc.
   5  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <linux/atomic.h>
  22 #include <linux/types.h>
  23 #include <linux/errno.h>
  24 #include <linux/init.h>
  25 #include <linux/kmsg_dump.h>
  26 #include <linux/console.h>
  27 #include <linux/module.h>
  28 #include <linux/pstore.h>
  29 #include <linux/zlib.h>
  30 #include <linux/string.h>
  31 #include <linux/timer.h>
  32 #include <linux/slab.h>
  33 #include <linux/uaccess.h>
  34 #include <linux/hardirq.h>
  35 #include <linux/jiffies.h>
  36 #include <linux/workqueue.h>
  37
  38 #include "internal.h"
  39
  40 /*
  41  * We defer making "oops" entries appear in pstore - see
  42  * whether the system is actually still running well enough
  43  * to let someone see the entry
  44  */
  45 static int pstore_update_ms = -1;
  46 module_param_named(update_ms, pstore_update_ms, int, 0600);
  47 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
  48                  "(default is -1, which means runtime updates are disabled; "
  49                  "enabling this option is not safe, it may lead to further "
  50                  "corruption on Oopses)");
  51
  52 static int pstore_new_entry;
  53
  54 static void pstore_timefunc(unsigned long);
  55 static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
  56
  57 static void pstore_dowork(struct work_struct *);
  58 static DECLARE_WORK(pstore_work, pstore_dowork);
  59
  60 /*
  61  * pstore_lock just protects "psinfo" during
  62  * calls to pstore_register()
  63  */
  64 static DEFINE_SPINLOCK(pstore_lock);
  65 struct pstore_info *psinfo;
  66
  67 static char *backend;
  68
  69 /* Compression parameters */
  70 #define COMPR_LEVEL 6
  71 #define WINDOW_BITS 12
  72 #define MEM_LEVEL 4
  73 static struct z_stream_s stream;
  74
  75 static char *big_oops_buf;
  76 static size_t big_oops_buf_sz;
  77
  78 /* How much of the console log to snapshot */
  79 static unsigned long kmsg_bytes = 10240;
  80
  81 void pstore_set_kmsg_bytes(int bytes)
  82 {
  83         kmsg_bytes = bytes;
  84 }
  85
  86 /* Tag each group of saved records with a sequence number */
  87 static int      oopscount;
  88
  89 static const char *get_reason_str(enum kmsg_dump_reason reason)
  90 {
  91         switch (reason) {
  92         case KMSG_DUMP_PANIC:
  93                 return "Panic";
  94         case KMSG_DUMP_OOPS:
  95                 return "Oops";
  96         case KMSG_DUMP_EMERG:
  97                 return "Emergency";
  98         case KMSG_DUMP_RESTART:
  99                 return "Restart";
 100         case KMSG_DUMP_HALT:
 101                 return "Halt";
 102         case KMSG_DUMP_POWEROFF:
 103                 return "Poweroff";
 104         default:
 105                 return "Unknown";
 106         }
 107 }
 108
 109 bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
 110 {
 111         /*
 112          * In case of NMI path, pstore shouldn't be blocked
 113          * regardless of reason.
 114          */
 115         if (in_nmi())
 116                 return true;
 117
 118         switch (reason) {
 119         /* In panic case, other cpus are stopped by smp_send_stop(). */
 120         case KMSG_DUMP_PANIC:
 121         /* Emergency restart shouldn't be blocked by spin lock. */
 122         case KMSG_DUMP_EMERG:
 123                 return true;
 124         default:
 125                 return false;
 126         }
 127 }
 128 EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
 129
 130 /* Derived from logfs_compress() */
 131 static int pstore_compress(const void *in, void *out, size_t inlen,
 132                                                         size_t outlen)
 133 {
 134         int err, ret;
 135
 136         ret = -EIO;
 137         err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
 138                                                 MEM_LEVEL, Z_DEFAULT_STRATEGY);
 139         if (err != Z_OK)
 140                 goto error;
 141
 142         stream.next_in = in;
 143         stream.avail_in = inlen;
 144         stream.total_in = 0;
 145         stream.next_out = out;
 146         stream.avail_out = outlen;
 147         stream.total_out = 0;
 148
 149         err = zlib_deflate(&stream, Z_FINISH);
 150         if (err != Z_STREAM_END)
 151                 goto error;
 152
 153         err = zlib_deflateEnd(&stream);
 154         if (err != Z_OK)
 155                 goto error;
 156
 157         if (stream.total_out >= stream.total_in)
 158                 goto error;
 159
 160         ret = stream.total_out;
 161 error:
 162         return ret;
 163 }
 164
 165 /* Derived from logfs_uncompress */
 166 static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
 167 {
 168         int err, ret;
 169
 170         ret = -EIO;
 171         err = zlib_inflateInit(&stream);
 172         if (err != Z_OK)
 173                 goto error;
 174
 175         stream.next_in = in;
 176         stream.avail_in = inlen;
 177         stream.total_in = 0;
 178         stream.next_out = out;
 179         stream.avail_out = outlen;
 180         stream.total_out = 0;
 181
 182         err = zlib_inflate(&stream, Z_FINISH);
 183         if (err != Z_STREAM_END)
 184                 goto error;
 185
 186         err = zlib_inflateEnd(&stream);
 187         if (err != Z_OK)
 188                 goto error;
 189
 190         ret = stream.total_out;
 191 error:
 192         return ret;
 193 }
 194
 195 static void allocate_buf_for_compression(void)
 196 {
 197         size_t size;
 198
 199         big_oops_buf_sz = (psinfo->bufsize * 100) / 45;
 200         big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
 201         if (big_oops_buf) {
 202                 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
 203                         zlib_inflate_workspacesize());
 204                 stream.workspace = kmalloc(size, GFP_KERNEL);
 205                 if (!stream.workspace) {
 206                         pr_err("pstore: No memory for compression workspace; "
 207                                 "skipping compression\n");
 208                         kfree(big_oops_buf);
 209                         big_oops_buf = NULL;
 210                 }
 211         } else {
 212                 pr_err("No memory for uncompressed data; "
 213                         "skipping compression\n");
 214                 stream.workspace = NULL;
 215         }
 216
 217 }
 218
 219 /*
 220  * Called when compression fails, since the printk buffer
 221  * would be fetched for compression calling it again when
 222  * compression fails would have moved the iterator of
 223  * printk buffer which results in fetching old contents.
 224  * Copy the recent messages from big_oops_buf to psinfo->buf
 225  */
 226 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
 227 {
 228         size_t total_len;
 229         size_t diff;
 230
 231         total_len = hsize + len;
 232
 233         if (total_len > psinfo->bufsize) {
 234                 diff = total_len - psinfo->bufsize + hsize;
 235                 memcpy(psinfo->buf, big_oops_buf, hsize);
 236                 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
 237                                         psinfo->bufsize - hsize);
 238                 total_len = psinfo->bufsize;
 239         } else
 240                 memcpy(psinfo->buf, big_oops_buf, total_len);
 241
 242         return total_len;
 243 }
 244
 245 /*
 246  * callback from kmsg_dump. (s2,l2) has the most recently
 247  * written bytes, older bytes are in (s1,l1). Save as much
 248  * as we can from the end of the buffer.
 249  */
 250 static void pstore_dump(struct kmsg_dumper *dumper,
 251                         enum kmsg_dump_reason reason)
 252 {
 253         unsigned long   total = 0;
 254         const char      *why;
 255         u64             id;
 256         unsigned int    part = 1;
 257         unsigned long   flags = 0;
 258         int             is_locked = 0;
 259         int             ret;
 260
 261         why = get_reason_str(reason);
 262
 263         if (pstore_cannot_block_path(reason)) {
 264                 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
 265                 if (!is_locked) {
 266                         pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
 267                                        , in_nmi() ? "NMI" : why);
 268                 }
 269         } else
 270                 spin_lock_irqsave(&psinfo->buf_lock, flags);
 271         oopscount++;
 272         while (total < kmsg_bytes) {
 273                 char *dst;
 274                 unsigned long size;
 275                 int hsize;
 276                 int zipped_len = -1;
 277                 size_t len;
 278                 bool compressed;
 279                 size_t total_len;
 280
 281                 if (big_oops_buf) {
 282                         dst = big_oops_buf;
 283                         hsize = sprintf(dst, "%s#%d Part%d\n", why,
 284                                                         oopscount, part);
 285                         size = big_oops_buf_sz - hsize;
 286
 287                         if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
 288                                                                 size, &len))
 289                                 break;
 290
 291                         zipped_len = pstore_compress(dst, psinfo->buf,
 292                                                 hsize + len, psinfo->bufsize);
 293
 294                         if (zipped_len > 0) {
 295                                 compressed = true;
 296                                 total_len = zipped_len;
 297                         } else {
 298                                 pr_err("pstore: compression failed for Part %d"
 299                                         " returned %d\n", part, zipped_len);
 300                                 pr_err("pstore: Capture uncompressed"
 301                                         " oops/panic report of Part %d\n", part);
 302                                 compressed = false;
 303                                 total_len = copy_kmsg_to_buffer(hsize, len);
 304                         }
 305                 } else {
 306                         dst = psinfo->buf;
 307                         hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount,
 308                                                                         part);
 309                         size = psinfo->bufsize - hsize;
 310                         dst += hsize;
 311
 312                         if (!kmsg_dump_get_buffer(dumper, true, dst,
 313                                                                 size, &len))
 314                                 break;
 315
 316                         compressed = false;
 317                         total_len = hsize + len;
 318                 }
 319
 320                 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
 321                                     oopscount, compressed, total_len, psinfo);
 322                 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
 323                         pstore_new_entry = 1;
 324
 325                 total += total_len;
 326                 part++;
 327         }
 328         if (pstore_cannot_block_path(reason)) {
 329                 if (is_locked)
 330                         spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 331         } else
 332                 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 333 }
 334
 335 static struct kmsg_dumper pstore_dumper = {
 336         .dump = pstore_dump,
 337 };
 338
 339 #ifdef CONFIG_PSTORE_CONSOLE
 340 static void pstore_console_write(struct console *con, const char *s, unsigned c)
 341 {
 342         const char *e = s + c;
 343
 344         while (s < e) {
 345                 unsigned long flags;
 346                 u64 id;
 347
 348                 if (c > psinfo->bufsize)
 349                         c = psinfo->bufsize;
 350
 351                 if (oops_in_progress) {
 352                         if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
 353                                 break;
 354                 } else {
 355                         spin_lock_irqsave(&psinfo->buf_lock, flags);
 356                 }
 357                 memcpy(psinfo->buf, s, c);
 358                 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
 359                 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 360                 s += c;
 361                 c = e - s;
 362         }
 363 }
 364
 365 static struct console pstore_console = {
 366         .name   = "pstore",
 367         .write  = pstore_console_write,
 368         .flags  = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
 369         .index  = -1,
 370 };
 371
 372 static void pstore_register_console(void)
 373 {
 374         register_console(&pstore_console);
 375 }
 376 #else
 377 static void pstore_register_console(void) {}
 378 #endif
 379
 380 static int pstore_write_compat(enum pstore_type_id type,
 381                                enum kmsg_dump_reason reason,
 382                                u64 *id, unsigned int part, int count,
 383                                bool compressed, size_t size,
 384                                struct pstore_info *psi)
 385 {
 386         return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
 387                              size, psi);
 388 }
 389
 390 /*
 391  * platform specific persistent storage driver registers with
 392  * us here. If pstore is already mounted, call the platform
 393  * read function right away to populate the file system. If not
 394  * then the pstore mount code will call us later to fill out
 395  * the file system.
 396  *
 397  * Register with kmsg_dump to save last part of console log on panic.
 398  */
 399 int pstore_register(struct pstore_info *psi)
 400 {
 401         struct module *owner = psi->owner;
 402
 403         if (backend && strcmp(backend, psi->name))
 404                 return -EPERM;
 405
 406         spin_lock(&pstore_lock);
 407         if (psinfo) {
 408                 spin_unlock(&pstore_lock);
 409                 return -EBUSY;
 410         }
 411
 412         if (!psi->write)
 413                 psi->write = pstore_write_compat;
 414         psinfo = psi;
 415         mutex_init(&psinfo->read_mutex);
 416         spin_unlock(&pstore_lock);
 417
 418         if (owner && !try_module_get(owner)) {
 419                 psinfo = NULL;
 420                 return -EINVAL;
 421         }
 422
 423         allocate_buf_for_compression();
 424
 425         if (pstore_is_mounted())
 426                 pstore_get_records(0);
 427
 428         kmsg_dump_register(&pstore_dumper);
 429         pstore_register_console();
 430         pstore_register_ftrace();
 431
 432         if (pstore_update_ms >= 0) {
 433                 pstore_timer.expires = jiffies +
 434                         msecs_to_jiffies(pstore_update_ms);
 435                 add_timer(&pstore_timer);
 436         }
 437
 438         pr_info("pstore: Registered %s as persistent store backend\n",
 439                 psi->name);
 440
 441         return 0;
 442 }
 443 EXPORT_SYMBOL_GPL(pstore_register);
 444
 445 /*
 446  * Read all the records from the persistent store. Create
 447  * files in our filesystem.  Don't warn about -EEXIST errors
 448  * when we are re-scanning the backing store looking to add new
 449  * error records.
 450  */
 451 void pstore_get_records(int quiet)
 452 {
 453         struct pstore_info *psi = psinfo;
 454         char                    *buf = NULL;
 455         ssize_t                 size;
 456         u64                     id;
 457         int                     count;
 458         enum pstore_type_id     type;
 459         struct timespec         time;
 460         int                     failed = 0, rc;
 461         bool                    compressed;
 462         int                     unzipped_len = -1;
 463
 464         if (!psi)
 465                 return;
 466
 467         mutex_lock(&psi->read_mutex);
 468         if (psi->open && psi->open(psi))
 469                 goto out;
 470
 471         while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
 472                                 psi)) > 0) {
 473                 if (compressed && (type == PSTORE_TYPE_DMESG)) {
 474                         if (big_oops_buf)
 475                                 unzipped_len = pstore_decompress(buf,
 476                                                         big_oops_buf, size,
 477                                                         big_oops_buf_sz);
 478
 479                         if (unzipped_len > 0) {
 480                                 buf = big_oops_buf;
 481                                 size = unzipped_len;
 482                                 compressed = false;
 483                         } else {
 484                                 pr_err("pstore: decompression failed;"
 485                                         "returned %d\n", unzipped_len);
 486                                 compressed = true;
 487                         }
 488                 }
 489                 rc = pstore_mkfile(type, psi->name, id, count, buf,
 490                                   compressed, (size_t)size, time, psi);
 491                 if (unzipped_len < 0) {
 492                         /* Free buffer other than big oops */
 493                         kfree(buf);
 494                         buf = NULL;
 495                 } else
 496                         unzipped_len = -1;
 497                 if (rc && (rc != -EEXIST || !quiet))
 498                         failed++;
 499         }
 500         if (psi->close)
 501                 psi->close(psi);
 502 out:
 503         mutex_unlock(&psi->read_mutex);
 504
 505         if (failed)
 506                 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
 507                        failed, psi->name);
 508 }
 509
 510 static void pstore_dowork(struct work_struct *work)
 511 {
 512         pstore_get_records(1);
 513 }
 514
 515 static void pstore_timefunc(unsigned long dummy)
 516 {
 517         if (pstore_new_entry) {
 518                 pstore_new_entry = 0;
 519                 schedule_work(&pstore_work);
 520         }
 521
 522         mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
 523 }
 524
 525 module_param(backend, charp, 0444);
 526 MODULE_PARM_DESC(backend, "Pstore backend to use");