drivers/firmware/dmi-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * dmi-sysfs.c
   4  *
   5  * This module exports the DMI tables read-only to userspace through the
   6  * sysfs file system.
   7  *
   8  * Data is currently found below
   9  *    /sys/firmware/dmi/...
  10  *
  11  * DMI attributes are presented in attribute files with names
  12  * formatted using %d-%d, so that the first integer indicates the
  13  * structure type (0-255), and the second field is the instance of that
  14  * entry.
  15  *
  16  * Copyright 2011 Google, Inc.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kobject.h>
  24 #include <linux/dmi.h>
  25 #include <linux/capability.h>
  26 #include <linux/slab.h>
  27 #include <linux/list.h>
  28 #include <linux/io.h>
  29 #include <asm/dmi.h>
  30
  31 #define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
  32                               the top entry type is only 8 bits */
  33
  34 struct dmi_sysfs_entry {
  35         struct dmi_header dh;
  36         struct kobject kobj;
  37         int instance;
  38         int position;
  39         struct list_head list;
  40         struct kobject *child;
  41 };
  42
  43 /*
  44  * Global list of dmi_sysfs_entry.  Even though this should only be
  45  * manipulated at setup and teardown, the lazy nature of the kobject
  46  * system means we get lazy removes.
  47  */
  48 static LIST_HEAD(entry_list);
  49 static DEFINE_SPINLOCK(entry_list_lock);
  50
  51 /* dmi_sysfs_attribute - Top level attribute. used by all entries. */
  52 struct dmi_sysfs_attribute {
  53         struct attribute attr;
  54         ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
  55 };
  56
  57 #define DMI_SYSFS_ATTR(_entry, _name) \
  58 struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
  59         .attr = {.name = __stringify(_name), .mode = 0400}, \
  60         .show = dmi_sysfs_##_entry##_##_name, \
  61 }
  62
  63 /*
  64  * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
  65  * mapped in.  Use in conjunction with dmi_sysfs_specialize_attr_ops.
  66  */
  67 struct dmi_sysfs_mapped_attribute {
  68         struct attribute attr;
  69         ssize_t (*show)(struct dmi_sysfs_entry *entry,
  70                         const struct dmi_header *dh,
  71                         char *buf);
  72 };
  73
  74 #define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
  75 struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
  76         .attr = {.name = __stringify(_name), .mode = 0400}, \
  77         .show = dmi_sysfs_##_entry##_##_name, \
  78 }
  79
  80 /*************************************************
  81  * Generic DMI entry support.
  82  *************************************************/
  83 static void dmi_entry_free(struct kobject *kobj)
  84 {
  85         kfree(kobj);
  86 }
  87
  88 static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
  89 {
  90         return container_of(kobj, struct dmi_sysfs_entry, kobj);
  91 }
  92
  93 static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
  94 {
  95         return container_of(attr, struct dmi_sysfs_attribute, attr);
  96 }
  97
  98 static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
  99                                    struct attribute *_attr, char *buf)
 100 {
 101         struct dmi_sysfs_entry *entry = to_entry(kobj);
 102         struct dmi_sysfs_attribute *attr = to_attr(_attr);
 103
 104         /* DMI stuff is only ever admin visible */
 105         if (!capable(CAP_SYS_ADMIN))
 106                 return -EACCES;
 107
 108         return attr->show(entry, buf);
 109 }
 110
 111 static const struct sysfs_ops dmi_sysfs_attr_ops = {
 112         .show = dmi_sysfs_attr_show,
 113 };
 114
 115 typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
 116                                 const struct dmi_header *dh, void *);
 117
 118 struct find_dmi_data {
 119         struct dmi_sysfs_entry  *entry;
 120         dmi_callback            callback;
 121         void                    *private;
 122         int                     instance_countdown;
 123         ssize_t                 ret;
 124 };
 125
 126 static void find_dmi_entry_helper(const struct dmi_header *dh,
 127                                   void *_data)
 128 {
 129         struct find_dmi_data *data = _data;
 130         struct dmi_sysfs_entry *entry = data->entry;
 131
 132         /* Is this the entry we want? */
 133         if (dh->type != entry->dh.type)
 134                 return;
 135
 136         if (data->instance_countdown != 0) {
 137                 /* try the next instance? */
 138                 data->instance_countdown--;
 139                 return;
 140         }
 141
 142         /*
 143          * Don't ever revisit the instance.  Short circuit later
 144          * instances by letting the instance_countdown run negative
 145          */
 146         data->instance_countdown--;
 147
 148         /* Found the entry */
 149         data->ret = data->callback(entry, dh, data->private);
 150 }
 151
 152 /* State for passing the read parameters through dmi_find_entry() */
 153 struct dmi_read_state {
 154         char *buf;
 155         loff_t pos;
 156         size_t count;
 157 };
 158
 159 static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
 160                               dmi_callback callback, void *private)
 161 {
 162         struct find_dmi_data data = {
 163                 .entry = entry,
 164                 .callback = callback,
 165                 .private = private,
 166                 .instance_countdown = entry->instance,
 167                 .ret = -EIO,  /* To signal the entry disappeared */
 168         };
 169         int ret;
 170
 171         ret = dmi_walk(find_dmi_entry_helper, &data);
 172         /* This shouldn't happen, but just in case. */
 173         if (ret)
 174                 return -EINVAL;
 175         return data.ret;
 176 }
 177
 178 /*
 179  * Calculate and return the byte length of the dmi entry identified by
 180  * dh.  This includes both the formatted portion as well as the
 181  * unformatted string space, including the two trailing nul characters.
 182  */
 183 static size_t dmi_entry_length(const struct dmi_header *dh)
 184 {
 185         const char *p = (const char *)dh;
 186
 187         p += dh->length;
 188
 189         while (p[0] || p[1])
 190                 p++;
 191
 192         return 2 + p - (const char *)dh;
 193 }
 194
 195 /*************************************************
 196  * Support bits for specialized DMI entry support
 197  *************************************************/
 198 struct dmi_entry_attr_show_data {
 199         struct attribute *attr;
 200         char *buf;
 201 };
 202
 203 static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
 204                                           const struct dmi_header *dh,
 205                                           void *_data)
 206 {
 207         struct dmi_entry_attr_show_data *data = _data;
 208         struct dmi_sysfs_mapped_attribute *attr;
 209
 210         attr = container_of(data->attr,
 211                             struct dmi_sysfs_mapped_attribute, attr);
 212         return attr->show(entry, dh, data->buf);
 213 }
 214
 215 static ssize_t dmi_entry_attr_show(struct kobject *kobj,
 216                                    struct attribute *attr,
 217                                    char *buf)
 218 {
 219         struct dmi_entry_attr_show_data data = {
 220                 .attr = attr,
 221                 .buf  = buf,
 222         };
 223         /* Find the entry according to our parent and call the
 224          * normalized show method hanging off of the attribute */
 225         return find_dmi_entry(to_entry(kobj->parent),
 226                               dmi_entry_attr_show_helper, &data);
 227 }
 228
 229 static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
 230         .show = dmi_entry_attr_show,
 231 };
 232
 233 /*************************************************
 234  * Specialized DMI entry support.
 235  *************************************************/
 236
 237 /*** Type 15 - System Event Table ***/
 238
 239 #define DMI_SEL_ACCESS_METHOD_IO8       0x00
 240 #define DMI_SEL_ACCESS_METHOD_IO2x8     0x01
 241 #define DMI_SEL_ACCESS_METHOD_IO16      0x02
 242 #define DMI_SEL_ACCESS_METHOD_PHYS32    0x03
 243 #define DMI_SEL_ACCESS_METHOD_GPNV      0x04
 244
 245 struct dmi_system_event_log {
 246         struct dmi_header header;
 247         u16     area_length;
 248         u16     header_start_offset;
 249         u16     data_start_offset;
 250         u8      access_method;
 251         u8      status;
 252         u32     change_token;
 253         union {
 254                 struct {
 255                         u16 index_addr;
 256                         u16 data_addr;
 257                 } io;
 258                 u32     phys_addr32;
 259                 u16     gpnv_handle;
 260                 u32     access_method_address;
 261         };
 262         u8      header_format;
 263         u8      type_descriptors_supported_count;
 264         u8      per_log_type_descriptor_length;
 265         u8      supported_log_type_descriptos[];
 266 } __packed;
 267
 268 #define DMI_SYSFS_SEL_FIELD(_field) \
 269 static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
 270                                       const struct dmi_header *dh, \
 271                                       char *buf) \
 272 { \
 273         struct dmi_system_event_log sel; \
 274         if (sizeof(sel) > dmi_entry_length(dh)) \
 275                 return -EIO; \
 276         memcpy(&sel, dh, sizeof(sel)); \
 277         return sprintf(buf, "%u\n", sel._field); \
 278 } \
 279 static DMI_SYSFS_MAPPED_ATTR(sel, _field)
 280
 281 DMI_SYSFS_SEL_FIELD(area_length);
 282 DMI_SYSFS_SEL_FIELD(header_start_offset);
 283 DMI_SYSFS_SEL_FIELD(data_start_offset);
 284 DMI_SYSFS_SEL_FIELD(access_method);
 285 DMI_SYSFS_SEL_FIELD(status);
 286 DMI_SYSFS_SEL_FIELD(change_token);
 287 DMI_SYSFS_SEL_FIELD(access_method_address);
 288 DMI_SYSFS_SEL_FIELD(header_format);
 289 DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
 290 DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);
 291
 292 static struct attribute *dmi_sysfs_sel_attrs[] = {
 293         &dmi_sysfs_attr_sel_area_length.attr,
 294         &dmi_sysfs_attr_sel_header_start_offset.attr,
 295         &dmi_sysfs_attr_sel_data_start_offset.attr,
 296         &dmi_sysfs_attr_sel_access_method.attr,
 297         &dmi_sysfs_attr_sel_status.attr,
 298         &dmi_sysfs_attr_sel_change_token.attr,
 299         &dmi_sysfs_attr_sel_access_method_address.attr,
 300         &dmi_sysfs_attr_sel_header_format.attr,
 301         &dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
 302         &dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
 303         NULL,
 304 };
 305 ATTRIBUTE_GROUPS(dmi_sysfs_sel);
 306
 307 static const struct kobj_type dmi_system_event_log_ktype = {
 308         .release = dmi_entry_free,
 309         .sysfs_ops = &dmi_sysfs_specialize_attr_ops,
 310         .default_groups = dmi_sysfs_sel_groups,
 311 };
 312
 313 #ifdef CONFIG_HAS_IOPORT
 314 typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
 315                             loff_t offset);
 316
 317 static DEFINE_MUTEX(io_port_lock);
 318
 319 static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
 320                                    loff_t offset)
 321 {
 322         u8 ret;
 323
 324         mutex_lock(&io_port_lock);
 325         outb((u8)offset, sel->io.index_addr);
 326         ret = inb(sel->io.data_addr);
 327         mutex_unlock(&io_port_lock);
 328         return ret;
 329 }
 330
 331 static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
 332                                      loff_t offset)
 333 {
 334         u8 ret;
 335
 336         mutex_lock(&io_port_lock);
 337         outb((u8)offset, sel->io.index_addr);
 338         outb((u8)(offset >> 8), sel->io.index_addr + 1);
 339         ret = inb(sel->io.data_addr);
 340         mutex_unlock(&io_port_lock);
 341         return ret;
 342 }
 343
 344 static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
 345                                     loff_t offset)
 346 {
 347         u8 ret;
 348
 349         mutex_lock(&io_port_lock);
 350         outw((u16)offset, sel->io.index_addr);
 351         ret = inb(sel->io.data_addr);
 352         mutex_unlock(&io_port_lock);
 353         return ret;
 354 }
 355
 356 static sel_io_reader sel_io_readers[] = {
 357         [DMI_SEL_ACCESS_METHOD_IO8]     = read_sel_8bit_indexed_io,
 358         [DMI_SEL_ACCESS_METHOD_IO2x8]   = read_sel_2x8bit_indexed_io,
 359         [DMI_SEL_ACCESS_METHOD_IO16]    = read_sel_16bit_indexed_io,
 360 };
 361
 362 static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
 363                                    const struct dmi_system_event_log *sel,
 364                                    char *buf, loff_t pos, size_t count)
 365 {
 366         ssize_t wrote = 0;
 367
 368         sel_io_reader io_reader = sel_io_readers[sel->access_method];
 369
 370         while (count && pos < sel->area_length) {
 371                 count--;
 372                 *(buf++) = io_reader(sel, pos++);
 373                 wrote++;
 374         }
 375
 376         return wrote;
 377 }
 378 #endif
 379
 380 static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
 381                                        const struct dmi_system_event_log *sel,
 382                                        char *buf, loff_t pos, size_t count)
 383 {
 384         u8 __iomem *mapped;
 385         ssize_t wrote = 0;
 386
 387         mapped = dmi_remap(sel->access_method_address, sel->area_length);
 388         if (!mapped)
 389                 return -EIO;
 390
 391         while (count && pos < sel->area_length) {
 392                 count--;
 393                 *(buf++) = readb(mapped + pos++);
 394                 wrote++;
 395         }
 396
 397         dmi_unmap(mapped);
 398         return wrote;
 399 }
 400
 401 static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
 402                                        const struct dmi_header *dh,
 403                                        void *_state)
 404 {
 405         struct dmi_read_state *state = _state;
 406         struct dmi_system_event_log sel;
 407
 408         if (sizeof(sel) > dmi_entry_length(dh))
 409                 return -EIO;
 410
 411         memcpy(&sel, dh, sizeof(sel));
 412
 413         switch (sel.access_method) {
 414 #ifdef CONFIG_HAS_IOPORT
 415         case DMI_SEL_ACCESS_METHOD_IO8:
 416         case DMI_SEL_ACCESS_METHOD_IO2x8:
 417         case DMI_SEL_ACCESS_METHOD_IO16:
 418                 return dmi_sel_raw_read_io(entry, &sel, state->buf,
 419                                            state->pos, state->count);
 420 #endif
 421         case DMI_SEL_ACCESS_METHOD_PHYS32:
 422                 return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
 423                                                state->pos, state->count);
 424         case DMI_SEL_ACCESS_METHOD_GPNV:
 425                 pr_info_ratelimited("dmi-sysfs: GPNV support missing.\n");
 426                 return -EIO;
 427         default:
 428                 pr_info_ratelimited("dmi-sysfs: Unknown access method %02x\n",
 429                         sel.access_method);
 430                 return -EIO;
 431         }
 432 }
 433
 434 static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj,
 435                                 struct bin_attribute *bin_attr,
 436                                 char *buf, loff_t pos, size_t count)
 437 {
 438         struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
 439         struct dmi_read_state state = {
 440                 .buf = buf,
 441                 .pos = pos,
 442                 .count = count,
 443         };
 444
 445         return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
 446 }
 447
 448 static struct bin_attribute dmi_sel_raw_attr = {
 449         .attr = {.name = "raw_event_log", .mode = 0400},
 450         .read = dmi_sel_raw_read,
 451 };
 452
 453 static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
 454 {
 455         int ret;
 456
 457         entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL);
 458         if (!entry->child)
 459                 return -ENOMEM;
 460         ret = kobject_init_and_add(entry->child,
 461                                    &dmi_system_event_log_ktype,
 462                                    &entry->kobj,
 463                                    "system_event_log");
 464         if (ret)
 465                 goto out_free;
 466
 467         ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr);
 468         if (ret)
 469                 goto out_del;
 470
 471         return 0;
 472
 473 out_del:
 474         kobject_del(entry->child);
 475 out_free:
 476         kfree(entry->child);
 477         return ret;
 478 }
 479
 480 /*************************************************
 481  * Generic DMI entry support.
 482  *************************************************/
 483
 484 static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
 485 {
 486         return sprintf(buf, "%d\n", entry->dh.length);
 487 }
 488
 489 static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
 490 {
 491         return sprintf(buf, "%d\n", entry->dh.handle);
 492 }
 493
 494 static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
 495 {
 496         return sprintf(buf, "%d\n", entry->dh.type);
 497 }
 498
 499 static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
 500                                         char *buf)
 501 {
 502         return sprintf(buf, "%d\n", entry->instance);
 503 }
 504
 505 static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
 506                                         char *buf)
 507 {
 508         return sprintf(buf, "%d\n", entry->position);
 509 }
 510
 511 static DMI_SYSFS_ATTR(entry, length);
 512 static DMI_SYSFS_ATTR(entry, handle);
 513 static DMI_SYSFS_ATTR(entry, type);
 514 static DMI_SYSFS_ATTR(entry, instance);
 515 static DMI_SYSFS_ATTR(entry, position);
 516
 517 static struct attribute *dmi_sysfs_entry_attrs[] = {
 518         &dmi_sysfs_attr_entry_length.attr,
 519         &dmi_sysfs_attr_entry_handle.attr,
 520         &dmi_sysfs_attr_entry_type.attr,
 521         &dmi_sysfs_attr_entry_instance.attr,
 522         &dmi_sysfs_attr_entry_position.attr,
 523         NULL,
 524 };
 525 ATTRIBUTE_GROUPS(dmi_sysfs_entry);
 526
 527 static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
 528                                          const struct dmi_header *dh,
 529                                          void *_state)
 530 {
 531         struct dmi_read_state *state = _state;
 532         size_t entry_length;
 533
 534         entry_length = dmi_entry_length(dh);
 535
 536         return memory_read_from_buffer(state->buf, state->count,
 537                                        &state->pos, dh, entry_length);
 538 }
 539
 540 static ssize_t dmi_entry_raw_read(struct file *filp,
 541                                   struct kobject *kobj,
 542                                   struct bin_attribute *bin_attr,
 543                                   char *buf, loff_t pos, size_t count)
 544 {
 545         struct dmi_sysfs_entry *entry = to_entry(kobj);
 546         struct dmi_read_state state = {
 547                 .buf = buf,
 548                 .pos = pos,
 549                 .count = count,
 550         };
 551
 552         return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
 553 }
 554
 555 static const struct bin_attribute dmi_entry_raw_attr = {
 556         .attr = {.name = "raw", .mode = 0400},
 557         .read = dmi_entry_raw_read,
 558 };
 559
 560 static void dmi_sysfs_entry_release(struct kobject *kobj)
 561 {
 562         struct dmi_sysfs_entry *entry = to_entry(kobj);
 563
 564         spin_lock(&entry_list_lock);
 565         list_del(&entry->list);
 566         spin_unlock(&entry_list_lock);
 567         kfree(entry);
 568 }
 569
 570 static const struct kobj_type dmi_sysfs_entry_ktype = {
 571         .release = dmi_sysfs_entry_release,
 572         .sysfs_ops = &dmi_sysfs_attr_ops,
 573         .default_groups = dmi_sysfs_entry_groups,
 574 };
 575
 576 static struct kset *dmi_kset;
 577
 578 /* Global count of all instances seen.  Only for setup */
 579 static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];
 580
 581 /* Global positional count of all entries seen.  Only for setup */
 582 static int __initdata position_count;
 583
 584 static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
 585                                              void *_ret)
 586 {
 587         struct dmi_sysfs_entry *entry;
 588         int *ret = _ret;
 589
 590         /* If a previous entry saw an error, short circuit */
 591         if (*ret)
 592                 return;
 593
 594         /* Allocate and register a new entry into the entries set */
 595         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 596         if (!entry) {
 597                 *ret = -ENOMEM;
 598                 return;
 599         }
 600
 601         /* Set the key */
 602         memcpy(&entry->dh, dh, sizeof(*dh));
 603         entry->instance = instance_counts[dh->type]++;
 604         entry->position = position_count++;
 605
 606         entry->kobj.kset = dmi_kset;
 607         *ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
 608                                     "%d-%d", dh->type, entry->instance);
 609
 610         /* Thread on the global list for cleanup */
 611         spin_lock(&entry_list_lock);
 612         list_add_tail(&entry->list, &entry_list);
 613         spin_unlock(&entry_list_lock);
 614
 615         if (*ret) {
 616                 kobject_put(&entry->kobj);
 617                 return;
 618         }
 619
 620         /* Handle specializations by type */
 621         switch (dh->type) {
 622         case DMI_ENTRY_SYSTEM_EVENT_LOG:
 623                 *ret = dmi_system_event_log(entry);
 624                 break;
 625         default:
 626                 /* No specialization */
 627                 break;
 628         }
 629         if (*ret)
 630                 goto out_err;
 631
 632         /* Create the raw binary file to access the entry */
 633         *ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr);
 634         if (*ret)
 635                 goto out_err;
 636
 637         return;
 638 out_err:
 639         kobject_put(entry->child);
 640         kobject_put(&entry->kobj);
 641         return;
 642 }
 643
 644 static void cleanup_entry_list(void)
 645 {
 646         struct dmi_sysfs_entry *entry, *next;
 647
 648         /* No locks, we are on our way out */
 649         list_for_each_entry_safe(entry, next, &entry_list, list) {
 650                 kobject_put(entry->child);
 651                 kobject_put(&entry->kobj);
 652         }
 653 }
 654
 655 static int __init dmi_sysfs_init(void)
 656 {
 657         int error;
 658         int val;
 659
 660         if (!dmi_kobj) {
 661                 pr_debug("dmi-sysfs: dmi entry is absent.\n");
 662                 error = -ENODATA;
 663                 goto err;
 664         }
 665
 666         dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
 667         if (!dmi_kset) {
 668                 error = -ENOMEM;
 669                 goto err;
 670         }
 671
 672         val = 0;
 673         error = dmi_walk(dmi_sysfs_register_handle, &val);
 674         if (error)
 675                 goto err;
 676         if (val) {
 677                 error = val;
 678                 goto err;
 679         }
 680
 681         pr_debug("dmi-sysfs: loaded.\n");
 682
 683         return 0;
 684 err:
 685         cleanup_entry_list();
 686         kset_unregister(dmi_kset);
 687         return error;
 688 }
 689
 690 /* clean up everything. */
 691 static void __exit dmi_sysfs_exit(void)
 692 {
 693         pr_debug("dmi-sysfs: unloading.\n");
 694         cleanup_entry_list();
 695         kset_unregister(dmi_kset);
 696 }
 697
 698 module_init(dmi_sysfs_init);
 699 module_exit(dmi_sysfs_exit);
 700
 701 MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
 702 MODULE_DESCRIPTION("DMI sysfs support");
 703 MODULE_LICENSE("GPL");