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