drivers/firmware/dmi-sysfs.c

   1 /*
   2  * dmi-sysfs.c
   3  *
   4  * This module exports the DMI tables read-only to userspace through the
   5  * sysfs file system.
   6  *
   7  * Data is currently found below
   8  *    /sys/firmware/dmi/...
   9  *
  10  * DMI attributes are presented in attribute files with names
  11  * formatted using %d-%d, so that the first integer indicates the
  12  * structure type (0-255), and the second field is the instance of that
  13  * entry.
  14  *
  15  * Copyright 2011 Google, Inc.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/kobject.h>
  23 #include <linux/dmi.h>
  24 #include <linux/capability.h>
  25 #include <linux/slab.h>
  26 #include <linux/list.h>
  27 #include <linux/io.h>
  28 #include <asm/dmi.h>
  29
  30 #define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
  31                               the top entry type is only 8 bits */
  32
  33 struct dmi_sysfs_entry {
  34         struct dmi_header dh;
  35         struct kobject kobj;
  36         int instance;
  37         int position;
  38         struct list_head list;
  39         struct kobject *child;
  40 };
  41
  42 /*
  43  * Global list of dmi_sysfs_entry.  Even though this should only be
  44  * manipulated at setup and teardown, the lazy nature of the kobject
  45  * system means we get lazy removes.
  46  */
  47 static LIST_HEAD(entry_list);
  48 static DEFINE_SPINLOCK(entry_list_lock);
  49
  50 /* dmi_sysfs_attribute - Top level attribute. used by all entries. */
  51 struct dmi_sysfs_attribute {
  52         struct attribute attr;
  53         ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
  54 };
  55
  56 #define DMI_SYSFS_ATTR(_entry, _name) \
  57 struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
  58         .attr = {.name = __stringify(_name), .mode = 0400}, \
  59         .show = dmi_sysfs_##_entry##_##_name, \
  60 }
  61
  62 /*
  63  * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
  64  * mapped in.  Use in conjunction with dmi_sysfs_specialize_attr_ops.
  65  */
  66 struct dmi_sysfs_mapped_attribute {
  67         struct attribute attr;
  68         ssize_t (*show)(struct dmi_sysfs_entry *entry,
  69                         const struct dmi_header *dh,
  70                         char *buf);
  71 };
  72
  73 #define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
  74 struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
  75         .attr = {.name = __stringify(_name), .mode = 0400}, \
  76         .show = dmi_sysfs_##_entry##_##_name, \
  77 }
  78
  79 /*************************************************
  80  * Generic DMI entry support.
  81  *************************************************/
  82 static void dmi_entry_free(struct kobject *kobj)
  83 {
  84         kfree(kobj);
  85 }
  86
  87 static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
  88 {
  89         return container_of(kobj, struct dmi_sysfs_entry, kobj);
  90 }
  91
  92 static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
  93 {
  94         return container_of(attr, struct dmi_sysfs_attribute, attr);
  95 }
  96
  97 static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
  98                                    struct attribute *_attr, char *buf)
  99 {
 100         struct dmi_sysfs_entry *entry = to_entry(kobj);
 101         struct dmi_sysfs_attribute *attr = to_attr(_attr);
 102
 103         /* DMI stuff is only ever admin visible */
 104         if (!capable(CAP_SYS_ADMIN))
 105                 return -EACCES;
 106
 107         return attr->show(entry, buf);
 108 }
 109
 110 static const struct sysfs_ops dmi_sysfs_attr_ops = {
 111         .show = dmi_sysfs_attr_show,
 112 };
 113
 114 typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
 115                                 const struct dmi_header *dh, void *);
 116
 117 struct find_dmi_data {
 118         struct dmi_sysfs_entry  *entry;
 119         dmi_callback            callback;
 120         void                    *private;
 121         int                     instance_countdown;
 122         ssize_t                 ret;
 123 };
 124
 125 static void find_dmi_entry_helper(const struct dmi_header *dh,
 126                                   void *_data)
 127 {
 128         struct find_dmi_data *data = _data;
 129         struct dmi_sysfs_entry *entry = data->entry;
 130
 131         /* Is this the entry we want? */
 132         if (dh->type != entry->dh.type)
 133                 return;
 134
 135         if (data->instance_countdown != 0) {
 136                 /* try the next instance? */
 137                 data->instance_countdown--;
 138                 return;
 139         }
 140
 141         /*
 142          * Don't ever revisit the instance.  Short circuit later
 143          * instances by letting the instance_countdown run negative
 144          */
 145         data->instance_countdown--;
 146
 147         /* Found the entry */
 148         data->ret = data->callback(entry, dh, data->private);
 149 }
 150
 151 /* State for passing the read parameters through dmi_find_entry() */
 152 struct dmi_read_state {
 153         char *buf;
 154         loff_t pos;
 155         size_t count;
 156 };
 157
 158 static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
 159                               dmi_callback callback, void *private)
 160 {
 161         struct find_dmi_data data = {
 162                 .entry = entry,
 163                 .callback = callback,
 164                 .private = private,
 165                 .instance_countdown = entry->instance,
 166                 .ret = -EIO,  /* To signal the entry disappeared */
 167         };
 168         int ret;
 169
 170         ret = dmi_walk(find_dmi_entry_helper, &data);
 171         /* This shouldn't happen, but just in case. */
 172         if (ret)
 173                 return -EINVAL;
 174         return data.ret;
 175 }
 176
 177 /*
 178  * Calculate and return the byte length of the dmi entry identified by
 179  * dh.  This includes both the formatted portion as well as the
 180  * unformatted string space, including the two trailing nul characters.
 181  */
 182 static size_t dmi_entry_length(const struct dmi_header *dh)
 183 {
 184         const char *p = (const char *)dh;
 185
 186         p += dh->length;
 187
 188         while (p[0] || p[1])
 189                 p++;
 190
 191         return 2 + p - (const char *)dh;
 192 }
 193
 194 /*************************************************
 195  * Support bits for specialized DMI entry support
 196  *************************************************/
 197 struct dmi_entry_attr_show_data {
 198         struct attribute *attr;
 199         char *buf;
 200 };
 201
 202 static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
 203                                           const struct dmi_header *dh,
 204                                           void *_data)
 205 {
 206         struct dmi_entry_attr_show_data *data = _data;
 207         struct dmi_sysfs_mapped_attribute *attr;
 208
 209         attr = container_of(data->attr,
 210                             struct dmi_sysfs_mapped_attribute, attr);
 211         return attr->show(entry, dh, data->buf);
 212 }
 213
 214 static ssize_t dmi_entry_attr_show(struct kobject *kobj,
 215                                    struct attribute *attr,
 216                                    char *buf)
 217 {
 218         struct dmi_entry_attr_show_data data = {
 219                 .attr = attr,
 220                 .buf  = buf,
 221         };
 222         /* Find the entry according to our parent and call the
 223          * normalized show method hanging off of the attribute */
 224         return find_dmi_entry(to_entry(kobj->parent),
 225                               dmi_entry_attr_show_helper, &data);
 226 }
 227
 228 static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
 229         .show = dmi_entry_attr_show,
 230 };
 231
 232 /*************************************************
 233  * Specialized DMI entry support.
 234  *************************************************/
 235
 236 /*** Type 15 - System Event Table ***/
 237
 238 #define DMI_SEL_ACCESS_METHOD_IO8       0x00
 239 #define DMI_SEL_ACCESS_METHOD_IO2x8     0x01
 240 #define DMI_SEL_ACCESS_METHOD_IO16      0x02
 241 #define DMI_SEL_ACCESS_METHOD_PHYS32    0x03
 242 #define DMI_SEL_ACCESS_METHOD_GPNV      0x04
 243
 244 struct dmi_system_event_log {
 245         struct dmi_header header;
 246         u16     area_length;
 247         u16     header_start_offset;
 248         u16     data_start_offset;
 249         u8      access_method;
 250         u8      status;
 251         u32     change_token;
 252         union {
 253                 struct {
 254                         u16 index_addr;
 255                         u16 data_addr;
 256                 } io;
 257                 u32     phys_addr32;
 258                 u16     gpnv_handle;
 259                 u32     access_method_address;
 260         };
 261         u8      header_format;
 262         u8      type_descriptors_supported_count;
 263         u8      per_log_type_descriptor_length;
 264         u8      supported_log_type_descriptos[0];
 265 } __packed;
 266
 267 #define DMI_SYSFS_SEL_FIELD(_field) \
 268 static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
 269                                       const struct dmi_header *dh, \
 270                                       char *buf) \
 271 { \
 272         struct dmi_system_event_log sel; \
 273         if (sizeof(sel) > dmi_entry_length(dh)) \
 274                 return -EIO; \
 275         memcpy(&sel, dh, sizeof(sel)); \
 276         return sprintf(buf, "%u\n", sel._field); \
 277 } \
 278 static DMI_SYSFS_MAPPED_ATTR(sel, _field)
 279
 280 DMI_SYSFS_SEL_FIELD(area_length);
 281 DMI_SYSFS_SEL_FIELD(header_start_offset);
 282 DMI_SYSFS_SEL_FIELD(data_start_offset);
 283 DMI_SYSFS_SEL_FIELD(access_method);
 284 DMI_SYSFS_SEL_FIELD(status);
 285 DMI_SYSFS_SEL_FIELD(change_token);
 286 DMI_SYSFS_SEL_FIELD(access_method_address);
 287 DMI_SYSFS_SEL_FIELD(header_format);
 288 DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
 289 DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);
 290
 291 static struct attribute *dmi_sysfs_sel_attrs[] = {
 292         &dmi_sysfs_attr_sel_area_length.attr,
 293         &dmi_sysfs_attr_sel_header_start_offset.attr,
 294         &dmi_sysfs_attr_sel_data_start_offset.attr,
 295         &dmi_sysfs_attr_sel_access_method.attr,
 296         &dmi_sysfs_attr_sel_status.attr,
 297         &dmi_sysfs_attr_sel_change_token.attr,
 298         &dmi_sysfs_attr_sel_access_method_address.attr,
 299         &dmi_sysfs_attr_sel_header_format.attr,
 300         &dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
 301         &dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
 302         NULL,
 303 };
 304
 305
 306 static struct kobj_type dmi_system_event_log_ktype = {
 307         .release = dmi_entry_free,
 308         .sysfs_ops = &dmi_sysfs_specialize_attr_ops,
 309         .default_attrs = dmi_sysfs_sel_attrs,
 310 };
 311
 312 typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
 313                             loff_t offset);
 314
 315 static DEFINE_MUTEX(io_port_lock);
 316
 317 static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
 318                                    loff_t offset)
 319 {
 320         u8 ret;
 321
 322         mutex_lock(&io_port_lock);
 323         outb((u8)offset, sel->io.index_addr);
 324         ret = inb(sel->io.data_addr);
 325         mutex_unlock(&io_port_lock);
 326         return ret;
 327 }
 328
 329 static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
 330                                      loff_t offset)
 331 {
 332         u8 ret;
 333
 334         mutex_lock(&io_port_lock);
 335         outb((u8)offset, sel->io.index_addr);
 336         outb((u8)(offset >> 8), sel->io.index_addr + 1);
 337         ret = inb(sel->io.data_addr);
 338         mutex_unlock(&io_port_lock);
 339         return ret;
 340 }
 341
 342 static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
 343                                     loff_t offset)
 344 {
 345         u8 ret;
 346
 347         mutex_lock(&io_port_lock);
 348         outw((u16)offset, sel->io.index_addr);
 349         ret = inb(sel->io.data_addr);
 350         mutex_unlock(&io_port_lock);
 351         return ret;
 352 }
 353
 354 static sel_io_reader sel_io_readers[] = {
 355         [DMI_SEL_ACCESS_METHOD_IO8]     = read_sel_8bit_indexed_io,
 356         [DMI_SEL_ACCESS_METHOD_IO2x8]   = read_sel_2x8bit_indexed_io,
 357         [DMI_SEL_ACCESS_METHOD_IO16]    = read_sel_16bit_indexed_io,
 358 };
 359
 360 static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
 361                                    const struct dmi_system_event_log *sel,
 362                                    char *buf, loff_t pos, size_t count)
 363 {
 364         ssize_t wrote = 0;
 365
 366         sel_io_reader io_reader = sel_io_readers[sel->access_method];
 367
 368         while (count && pos < sel->area_length) {
 369                 count--;
 370                 *(buf++) = io_reader(sel, pos++);
 371                 wrote++;
 372         }
 373
 374         return wrote;
 375 }
 376
 377 static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
 378                                        const struct dmi_system_event_log *sel,
 379                                        char *buf, loff_t pos, size_t count)
 380 {
 381         u8 __iomem *mapped;
 382         ssize_t wrote = 0;
 383
 384         mapped = dmi_remap(sel->access_method_address, sel->area_length);
 385         if (!mapped)
 386                 return -EIO;
 387
 388         while (count && pos < sel->area_length) {
 389                 count--;
 390                 *(buf++) = readb(mapped + pos++);
 391                 wrote++;
 392         }
 393
 394         dmi_unmap(mapped);
 395         return wrote;
 396 }
 397
 398 static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
 399                                        const struct dmi_header *dh,
 400                                        void *_state)
 401 {
 402         struct dmi_read_state *state = _state;
 403         struct dmi_system_event_log sel;
 404
 405         if (sizeof(sel) > dmi_entry_length(dh))
 406                 return -EIO;
 407
 408         memcpy(&sel, dh, sizeof(sel));
 409
 410         switch (sel.access_method) {
 411         case DMI_SEL_ACCESS_METHOD_IO8:
 412         case DMI_SEL_ACCESS_METHOD_IO2x8:
 413         case DMI_SEL_ACCESS_METHOD_IO16:
 414                 return dmi_sel_raw_read_io(entry, &sel, state->buf,
 415                                            state->pos, state->count);
 416         case DMI_SEL_ACCESS_METHOD_PHYS32:
 417                 return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
 418                                                state->pos, state->count);
 419         case DMI_SEL_ACCESS_METHOD_GPNV:
 420                 pr_info("dmi-sysfs: GPNV support missing.\n");
 421                 return -EIO;
 422         default:
 423                 pr_info("dmi-sysfs: Unknown access method %02x\n",
 424                         sel.access_method);
 425                 return -EIO;
 426         }
 427 }
 428
 429 static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj,
 430                                 struct bin_attribute *bin_attr,
 431                                 char *buf, loff_t pos, size_t count)
 432 {
 433         struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
 434         struct dmi_read_state state = {
 435                 .buf = buf,
 436                 .pos = pos,
 437                 .count = count,
 438         };
 439
 440         return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
 441 }
 442
 443 static struct bin_attribute dmi_sel_raw_attr = {
 444         .attr = {.name = "raw_event_log", .mode = 0400},
 445         .read = dmi_sel_raw_read,
 446 };
 447
 448 static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
 449 {
 450         int ret;
 451
 452         entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL);
 453         if (!entry->child)
 454                 return -ENOMEM;
 455         ret = kobject_init_and_add(entry->child,
 456                                    &dmi_system_event_log_ktype,
 457                                    &entry->kobj,
 458                                    "system_event_log");
 459         if (ret)
 460                 goto out_free;
 461
 462         ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr);
 463         if (ret)
 464                 goto out_del;
 465
 466         return 0;
 467
 468 out_del:
 469         kobject_del(entry->child);
 470 out_free:
 471         kfree(entry->child);
 472         return ret;
 473 }
 474
 475 /*************************************************
 476  * Generic DMI entry support.
 477  *************************************************/
 478
 479 static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
 480 {
 481         return sprintf(buf, "%d\n", entry->dh.length);
 482 }
 483
 484 static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
 485 {
 486         return sprintf(buf, "%d\n", entry->dh.handle);
 487 }
 488
 489 static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
 490 {
 491         return sprintf(buf, "%d\n", entry->dh.type);
 492 }
 493
 494 static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
 495                                         char *buf)
 496 {
 497         return sprintf(buf, "%d\n", entry->instance);
 498 }
 499
 500 static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
 501                                         char *buf)
 502 {
 503         return sprintf(buf, "%d\n", entry->position);
 504 }
 505
 506 static DMI_SYSFS_ATTR(entry, length);
 507 static DMI_SYSFS_ATTR(entry, handle);
 508 static DMI_SYSFS_ATTR(entry, type);
 509 static DMI_SYSFS_ATTR(entry, instance);
 510 static DMI_SYSFS_ATTR(entry, position);
 511
 512 static struct attribute *dmi_sysfs_entry_attrs[] = {
 513         &dmi_sysfs_attr_entry_length.attr,
 514         &dmi_sysfs_attr_entry_handle.attr,
 515         &dmi_sysfs_attr_entry_type.attr,
 516         &dmi_sysfs_attr_entry_instance.attr,
 517         &dmi_sysfs_attr_entry_position.attr,
 518         NULL,
 519 };
 520
 521 static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
 522                                          const struct dmi_header *dh,
 523                                          void *_state)
 524 {
 525         struct dmi_read_state *state = _state;
 526         size_t entry_length;
 527
 528         entry_length = dmi_entry_length(dh);
 529
 530         return memory_read_from_buffer(state->buf, state->count,
 531                                        &state->pos, dh, entry_length);
 532 }
 533
 534 static ssize_t dmi_entry_raw_read(struct file *filp,
 535                                   struct kobject *kobj,
 536                                   struct bin_attribute *bin_attr,
 537                                   char *buf, loff_t pos, size_t count)
 538 {
 539         struct dmi_sysfs_entry *entry = to_entry(kobj);
 540         struct dmi_read_state state = {
 541                 .buf = buf,
 542                 .pos = pos,
 543                 .count = count,
 544         };
 545
 546         return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
 547 }
 548
 549 static const struct bin_attribute dmi_entry_raw_attr = {
 550         .attr = {.name = "raw", .mode = 0400},
 551         .read = dmi_entry_raw_read,
 552 };
 553
 554 static void dmi_sysfs_entry_release(struct kobject *kobj)
 555 {
 556         struct dmi_sysfs_entry *entry = to_entry(kobj);
 557
 558         spin_lock(&entry_list_lock);
 559         list_del(&entry->list);
 560         spin_unlock(&entry_list_lock);
 561         kfree(entry);
 562 }
 563
 564 static struct kobj_type dmi_sysfs_entry_ktype = {
 565         .release = dmi_sysfs_entry_release,
 566         .sysfs_ops = &dmi_sysfs_attr_ops,
 567         .default_attrs = dmi_sysfs_entry_attrs,
 568 };
 569
 570 static struct kset *dmi_kset;
 571
 572 /* Global count of all instances seen.  Only for setup */
 573 static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];
 574
 575 /* Global positional count of all entries seen.  Only for setup */
 576 static int __initdata position_count;
 577
 578 static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
 579                                              void *_ret)
 580 {
 581         struct dmi_sysfs_entry *entry;
 582         int *ret = _ret;
 583
 584         /* If a previous entry saw an error, short circuit */
 585         if (*ret)
 586                 return;
 587
 588         /* Allocate and register a new entry into the entries set */
 589         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 590         if (!entry) {
 591                 *ret = -ENOMEM;
 592                 return;
 593         }
 594
 595         /* Set the key */
 596         memcpy(&entry->dh, dh, sizeof(*dh));
 597         entry->instance = instance_counts[dh->type]++;
 598         entry->position = position_count++;
 599
 600         entry->kobj.kset = dmi_kset;
 601         *ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
 602                                     "%d-%d", dh->type, entry->instance);
 603
 604         if (*ret) {
 605                 kfree(entry);
 606                 return;
 607         }
 608
 609         /* Thread on the global list for cleanup */
 610         spin_lock(&entry_list_lock);
 611         list_add_tail(&entry->list, &entry_list);
 612         spin_unlock(&entry_list_lock);
 613
 614         /* Handle specializations by type */
 615         switch (dh->type) {
 616         case DMI_ENTRY_SYSTEM_EVENT_LOG:
 617                 *ret = dmi_system_event_log(entry);
 618                 break;
 619         default:
 620                 /* No specialization */
 621                 break;
 622         }
 623         if (*ret)
 624                 goto out_err;
 625
 626         /* Create the raw binary file to access the entry */
 627         *ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr);
 628         if (*ret)
 629                 goto out_err;
 630
 631         return;
 632 out_err:
 633         kobject_put(entry->child);
 634         kobject_put(&entry->kobj);
 635         return;
 636 }
 637
 638 static void cleanup_entry_list(void)
 639 {
 640         struct dmi_sysfs_entry *entry, *next;
 641
 642         /* No locks, we are on our way out */
 643         list_for_each_entry_safe(entry, next, &entry_list, list) {
 644                 kobject_put(entry->child);
 645                 kobject_put(&entry->kobj);
 646         }
 647 }
 648
 649 static int __init dmi_sysfs_init(void)
 650 {
 651         int error;
 652         int val;
 653
 654         if (!dmi_kobj) {
 655                 pr_debug("dmi-sysfs: dmi entry is absent.\n");
 656                 error = -ENODATA;
 657                 goto err;
 658         }
 659
 660         dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
 661         if (!dmi_kset) {
 662                 error = -ENOMEM;
 663                 goto err;
 664         }
 665
 666         val = 0;
 667         error = dmi_walk(dmi_sysfs_register_handle, &val);
 668         if (error)
 669                 goto err;
 670         if (val) {
 671                 error = val;
 672                 goto err;
 673         }
 674
 675         pr_debug("dmi-sysfs: loaded.\n");
 676
 677         return 0;
 678 err:
 679         cleanup_entry_list();
 680         kset_unregister(dmi_kset);
 681         return error;
 682 }
 683
 684 /* clean up everything. */
 685 static void __exit dmi_sysfs_exit(void)
 686 {
 687         pr_debug("dmi-sysfs: unloading.\n");
 688         cleanup_entry_list();
 689         kset_unregister(dmi_kset);
 690 }
 691
 692 module_init(dmi_sysfs_init);
 693 module_exit(dmi_sysfs_exit);
 694
 695 MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
 696 MODULE_DESCRIPTION("DMI sysfs support");
 697 MODULE_LICENSE("GPL");