drivers/firmware/efi/efivars.c

   1 /*
   2  * Originally from efivars.c,
   3  *
   4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
   5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
   6  *
   7  * This code takes all variables accessible from EFI runtime and
   8  *  exports them via sysfs
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  * Changelog:
  25  *
  26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
  27  *   remove check for efi_enabled in exit
  28  *   add MODULE_VERSION
  29  *
  30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
  31  *   minor bug fixes
  32  *
  33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
  34  *   converted driver to export variable information via sysfs
  35  *   and moved to drivers/firmware directory
  36  *   bumped revision number to v0.07 to reflect conversion & move
  37  *
  38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
  39  *   fix locking per Peter Chubb's findings
  40  *
  41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
  42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_to_str()
  43  *
  44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
  45  *   use list_for_each_safe when deleting vars.
  46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
  47  *   v0.04 release to linux-ia64@linuxia64.org
  48  *
  49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
  50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
  51  *   efi.c own the /proc/efi directory.
  52  *   v0.03 release to linux-ia64@linuxia64.org
  53  *
  54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  55  *   At the request of Stephane, moved ownership of /proc/efi
  56  *   to efi.c, and now efivars lives under /proc/efi/vars.
  57  *
  58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  59  *   Feedback received from Stephane Eranian incorporated.
  60  *   efivar_write() checks copy_from_user() return value.
  61  *   efivar_read/write() returns proper errno.
  62  *   v0.02 release to linux-ia64@linuxia64.org
  63  *
  64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
  65  *   v0.01 release to linux-ia64@linuxia64.org
  66  */
  67
  68 #include <linux/efi.h>
  69 #include <linux/module.h>
  70 #include <linux/slab.h>
  71 #include <linux/ucs2_string.h>
  72 #include <linux/compat.h>
  73
  74 #define EFIVARS_VERSION "0.08"
  75 #define EFIVARS_DATE "2004-May-17"
  76
  77 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  78 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  79 MODULE_LICENSE("GPL");
  80 MODULE_VERSION(EFIVARS_VERSION);
  81 MODULE_ALIAS("platform:efivars");
  82
  83 LIST_HEAD(efivar_sysfs_list);
  84 EXPORT_SYMBOL_GPL(efivar_sysfs_list);
  85
  86 static struct kset *efivars_kset;
  87
  88 static struct bin_attribute *efivars_new_var;
  89 static struct bin_attribute *efivars_del_var;
  90
  91 struct compat_efi_variable {
  92         efi_char16_t  VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
  93         efi_guid_t    VendorGuid;
  94         __u32         DataSize;
  95         __u8          Data[1024];
  96         __u32         Status;
  97         __u32         Attributes;
  98 } __packed;
  99
 100 struct efivar_attribute {
 101         struct attribute attr;
 102         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 103         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 104 };
 105
 106 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 107 struct efivar_attribute efivar_attr_##_name = { \
 108         .attr = {.name = __stringify(_name), .mode = _mode}, \
 109         .show = _show, \
 110         .store = _store, \
 111 };
 112
 113 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 114 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 115
 116 /*
 117  * Prototype for sysfs creation function
 118  */
 119 static int
 120 efivar_create_sysfs_entry(struct efivar_entry *new_var);
 121
 122 static ssize_t
 123 efivar_guid_read(struct efivar_entry *entry, char *buf)
 124 {
 125         struct efi_variable *var = &entry->var;
 126         char *str = buf;
 127
 128         if (!entry || !buf)
 129                 return 0;
 130
 131         efi_guid_to_str(&var->VendorGuid, str);
 132         str += strlen(str);
 133         str += sprintf(str, "\n");
 134
 135         return str - buf;
 136 }
 137
 138 static ssize_t
 139 efivar_attr_read(struct efivar_entry *entry, char *buf)
 140 {
 141         struct efi_variable *var = &entry->var;
 142         char *str = buf;
 143
 144         if (!entry || !buf)
 145                 return -EINVAL;
 146
 147         var->DataSize = 1024;
 148         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 149                 return -EIO;
 150
 151         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 152                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 153         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 154                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 155         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 156                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 157         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 158                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 159         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 160                 str += sprintf(str,
 161                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 162         if (var->Attributes &
 163                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 164                 str += sprintf(str,
 165                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 166         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 167                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 168         return str - buf;
 169 }
 170
 171 static ssize_t
 172 efivar_size_read(struct efivar_entry *entry, char *buf)
 173 {
 174         struct efi_variable *var = &entry->var;
 175         char *str = buf;
 176
 177         if (!entry || !buf)
 178                 return -EINVAL;
 179
 180         var->DataSize = 1024;
 181         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 182                 return -EIO;
 183
 184         str += sprintf(str, "0x%lx\n", var->DataSize);
 185         return str - buf;
 186 }
 187
 188 static ssize_t
 189 efivar_data_read(struct efivar_entry *entry, char *buf)
 190 {
 191         struct efi_variable *var = &entry->var;
 192
 193         if (!entry || !buf)
 194                 return -EINVAL;
 195
 196         var->DataSize = 1024;
 197         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 198                 return -EIO;
 199
 200         memcpy(buf, var->Data, var->DataSize);
 201         return var->DataSize;
 202 }
 203
 204 static inline int
 205 sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
 206              unsigned long size, u32 attributes, u8 *data)
 207 {
 208         /*
 209          * If only updating the variable data, then the name
 210          * and guid should remain the same
 211          */
 212         if (memcmp(name, var->VariableName, sizeof(var->VariableName)) ||
 213                 efi_guidcmp(vendor, var->VendorGuid)) {
 214                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 215                 return -EINVAL;
 216         }
 217
 218         if ((size <= 0) || (attributes == 0)){
 219                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 220                 return -EINVAL;
 221         }
 222
 223         if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
 224             efivar_validate(vendor, name, data, size) == false) {
 225                 printk(KERN_ERR "efivars: Malformed variable content\n");
 226                 return -EINVAL;
 227         }
 228
 229         return 0;
 230 }
 231
 232 static inline bool is_compat(void)
 233 {
 234         if (IS_ENABLED(CONFIG_COMPAT) && in_compat_syscall())
 235                 return true;
 236
 237         return false;
 238 }
 239
 240 static void
 241 copy_out_compat(struct efi_variable *dst, struct compat_efi_variable *src)
 242 {
 243         memcpy(dst->VariableName, src->VariableName, EFI_VAR_NAME_LEN);
 244         memcpy(dst->Data, src->Data, sizeof(src->Data));
 245
 246         dst->VendorGuid = src->VendorGuid;
 247         dst->DataSize = src->DataSize;
 248         dst->Attributes = src->Attributes;
 249 }
 250
 251 /*
 252  * We allow each variable to be edited via rewriting the
 253  * entire efi variable structure.
 254  */
 255 static ssize_t
 256 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 257 {
 258         struct efi_variable *new_var, *var = &entry->var;
 259         efi_char16_t *name;
 260         unsigned long size;
 261         efi_guid_t vendor;
 262         u32 attributes;
 263         u8 *data;
 264         int err;
 265
 266         if (is_compat()) {
 267                 struct compat_efi_variable *compat;
 268
 269                 if (count != sizeof(*compat))
 270                         return -EINVAL;
 271
 272                 compat = (struct compat_efi_variable *)buf;
 273                 attributes = compat->Attributes;
 274                 vendor = compat->VendorGuid;
 275                 name = compat->VariableName;
 276                 size = compat->DataSize;
 277                 data = compat->Data;
 278
 279                 err = sanity_check(var, name, vendor, size, attributes, data);
 280                 if (err)
 281                         return err;
 282
 283                 copy_out_compat(&entry->var, compat);
 284         } else {
 285                 if (count != sizeof(struct efi_variable))
 286                         return -EINVAL;
 287
 288                 new_var = (struct efi_variable *)buf;
 289
 290                 attributes = new_var->Attributes;
 291                 vendor = new_var->VendorGuid;
 292                 name = new_var->VariableName;
 293                 size = new_var->DataSize;
 294                 data = new_var->Data;
 295
 296                 err = sanity_check(var, name, vendor, size, attributes, data);
 297                 if (err)
 298                         return err;
 299
 300                 memcpy(&entry->var, new_var, count);
 301         }
 302
 303         err = efivar_entry_set(entry, attributes, size, data, NULL);
 304         if (err) {
 305                 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
 306                 return -EIO;
 307         }
 308
 309         return count;
 310 }
 311
 312 static ssize_t
 313 efivar_show_raw(struct efivar_entry *entry, char *buf)
 314 {
 315         struct efi_variable *var = &entry->var;
 316         struct compat_efi_variable *compat;
 317         size_t size;
 318
 319         if (!entry || !buf)
 320                 return 0;
 321
 322         var->DataSize = 1024;
 323         if (efivar_entry_get(entry, &entry->var.Attributes,
 324                              &entry->var.DataSize, entry->var.Data))
 325                 return -EIO;
 326
 327         if (is_compat()) {
 328                 compat = (struct compat_efi_variable *)buf;
 329
 330                 size = sizeof(*compat);
 331                 memcpy(compat->VariableName, var->VariableName,
 332                         EFI_VAR_NAME_LEN);
 333                 memcpy(compat->Data, var->Data, sizeof(compat->Data));
 334
 335                 compat->VendorGuid = var->VendorGuid;
 336                 compat->DataSize = var->DataSize;
 337                 compat->Attributes = var->Attributes;
 338         } else {
 339                 size = sizeof(*var);
 340                 memcpy(buf, var, size);
 341         }
 342
 343         return size;
 344 }
 345
 346 /*
 347  * Generic read/write functions that call the specific functions of
 348  * the attributes...
 349  */
 350 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 351                                 char *buf)
 352 {
 353         struct efivar_entry *var = to_efivar_entry(kobj);
 354         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 355         ssize_t ret = -EIO;
 356
 357         if (!capable(CAP_SYS_ADMIN))
 358                 return -EACCES;
 359
 360         if (efivar_attr->show) {
 361                 ret = efivar_attr->show(var, buf);
 362         }
 363         return ret;
 364 }
 365
 366 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 367                                 const char *buf, size_t count)
 368 {
 369         struct efivar_entry *var = to_efivar_entry(kobj);
 370         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 371         ssize_t ret = -EIO;
 372
 373         if (!capable(CAP_SYS_ADMIN))
 374                 return -EACCES;
 375
 376         if (efivar_attr->store)
 377                 ret = efivar_attr->store(var, buf, count);
 378
 379         return ret;
 380 }
 381
 382 static const struct sysfs_ops efivar_attr_ops = {
 383         .show = efivar_attr_show,
 384         .store = efivar_attr_store,
 385 };
 386
 387 static void efivar_release(struct kobject *kobj)
 388 {
 389         struct efivar_entry *var = to_efivar_entry(kobj);
 390         kfree(var);
 391 }
 392
 393 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 394 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 395 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 396 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 397 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 398
 399 static struct attribute *def_attrs[] = {
 400         &efivar_attr_guid.attr,
 401         &efivar_attr_size.attr,
 402         &efivar_attr_attributes.attr,
 403         &efivar_attr_data.attr,
 404         &efivar_attr_raw_var.attr,
 405         NULL,
 406 };
 407
 408 static struct kobj_type efivar_ktype = {
 409         .release = efivar_release,
 410         .sysfs_ops = &efivar_attr_ops,
 411         .default_attrs = def_attrs,
 412 };
 413
 414 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 415                              struct bin_attribute *bin_attr,
 416                              char *buf, loff_t pos, size_t count)
 417 {
 418         struct compat_efi_variable *compat = (struct compat_efi_variable *)buf;
 419         struct efi_variable *new_var = (struct efi_variable *)buf;
 420         struct efivar_entry *new_entry;
 421         bool need_compat = is_compat();
 422         efi_char16_t *name;
 423         unsigned long size;
 424         u32 attributes;
 425         u8 *data;
 426         int err;
 427
 428         if (!capable(CAP_SYS_ADMIN))
 429                 return -EACCES;
 430
 431         if (need_compat) {
 432                 if (count != sizeof(*compat))
 433                         return -EINVAL;
 434
 435                 attributes = compat->Attributes;
 436                 name = compat->VariableName;
 437                 size = compat->DataSize;
 438                 data = compat->Data;
 439         } else {
 440                 if (count != sizeof(*new_var))
 441                         return -EINVAL;
 442
 443                 attributes = new_var->Attributes;
 444                 name = new_var->VariableName;
 445                 size = new_var->DataSize;
 446                 data = new_var->Data;
 447         }
 448
 449         if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
 450             efivar_validate(new_var->VendorGuid, name, data,
 451                             size) == false) {
 452                 printk(KERN_ERR "efivars: Malformed variable content\n");
 453                 return -EINVAL;
 454         }
 455
 456         new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
 457         if (!new_entry)
 458                 return -ENOMEM;
 459
 460         if (need_compat)
 461                 copy_out_compat(&new_entry->var, compat);
 462         else
 463                 memcpy(&new_entry->var, new_var, sizeof(*new_var));
 464
 465         err = efivar_entry_set(new_entry, attributes, size,
 466                                data, &efivar_sysfs_list);
 467         if (err) {
 468                 if (err == -EEXIST)
 469                         err = -EINVAL;
 470                 goto out;
 471         }
 472
 473         if (efivar_create_sysfs_entry(new_entry)) {
 474                 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
 475                 kfree(new_entry);
 476         }
 477         return count;
 478
 479 out:
 480         kfree(new_entry);
 481         return err;
 482 }
 483
 484 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 485                              struct bin_attribute *bin_attr,
 486                              char *buf, loff_t pos, size_t count)
 487 {
 488         struct efi_variable *del_var = (struct efi_variable *)buf;
 489         struct compat_efi_variable *compat;
 490         struct efivar_entry *entry;
 491         efi_char16_t *name;
 492         efi_guid_t vendor;
 493         int err = 0;
 494
 495         if (!capable(CAP_SYS_ADMIN))
 496                 return -EACCES;
 497
 498         if (is_compat()) {
 499                 if (count != sizeof(*compat))
 500                         return -EINVAL;
 501
 502                 compat = (struct compat_efi_variable *)buf;
 503                 name = compat->VariableName;
 504                 vendor = compat->VendorGuid;
 505         } else {
 506                 if (count != sizeof(*del_var))
 507                         return -EINVAL;
 508
 509                 name = del_var->VariableName;
 510                 vendor = del_var->VendorGuid;
 511         }
 512
 513         efivar_entry_iter_begin();
 514         entry = efivar_entry_find(name, vendor, &efivar_sysfs_list, true);
 515         if (!entry)
 516                 err = -EINVAL;
 517         else if (__efivar_entry_delete(entry))
 518                 err = -EIO;
 519
 520         if (err) {
 521                 efivar_entry_iter_end();
 522                 return err;
 523         }
 524
 525         if (!entry->scanning) {
 526                 efivar_entry_iter_end();
 527                 efivar_unregister(entry);
 528         } else
 529                 efivar_entry_iter_end();
 530
 531         /* It's dead Jim.... */
 532         return count;
 533 }
 534
 535 /**
 536  * efivar_create_sysfs_entry - create a new entry in sysfs
 537  * @new_var: efivar entry to create
 538  *
 539  * Returns 0 on success, negative error code on failure
 540  */
 541 static int
 542 efivar_create_sysfs_entry(struct efivar_entry *new_var)
 543 {
 544         int short_name_size;
 545         char *short_name;
 546         unsigned long utf8_name_size;
 547         efi_char16_t *variable_name = new_var->var.VariableName;
 548         int ret;
 549
 550         /*
 551          * Length of the variable bytes in UTF8, plus the '-' separator,
 552          * plus the GUID, plus trailing NUL
 553          */
 554         utf8_name_size = ucs2_utf8size(variable_name);
 555         short_name_size = utf8_name_size + 1 + EFI_VARIABLE_GUID_LEN + 1;
 556
 557         short_name = kmalloc(short_name_size, GFP_KERNEL);
 558         if (!short_name)
 559                 return -ENOMEM;
 560
 561         ucs2_as_utf8(short_name, variable_name, short_name_size);
 562
 563         /* This is ugly, but necessary to separate one vendor's
 564            private variables from another's.         */
 565         short_name[utf8_name_size] = '-';
 566         efi_guid_to_str(&new_var->var.VendorGuid,
 567                          short_name + utf8_name_size + 1);
 568
 569         new_var->kobj.kset = efivars_kset;
 570
 571         ret = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
 572                                    NULL, "%s", short_name);
 573         kfree(short_name);
 574         if (ret)
 575                 return ret;
 576
 577         kobject_uevent(&new_var->kobj, KOBJ_ADD);
 578         efivar_entry_add(new_var, &efivar_sysfs_list);
 579
 580         return 0;
 581 }
 582
 583 static int
 584 create_efivars_bin_attributes(void)
 585 {
 586         struct bin_attribute *attr;
 587         int error;
 588
 589         /* new_var */
 590         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 591         if (!attr)
 592                 return -ENOMEM;
 593
 594         attr->attr.name = "new_var";
 595         attr->attr.mode = 0200;
 596         attr->write = efivar_create;
 597         efivars_new_var = attr;
 598
 599         /* del_var */
 600         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 601         if (!attr) {
 602                 error = -ENOMEM;
 603                 goto out_free;
 604         }
 605         attr->attr.name = "del_var";
 606         attr->attr.mode = 0200;
 607         attr->write = efivar_delete;
 608         efivars_del_var = attr;
 609
 610         sysfs_bin_attr_init(efivars_new_var);
 611         sysfs_bin_attr_init(efivars_del_var);
 612
 613         /* Register */
 614         error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
 615         if (error) {
 616                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
 617                         " due to error %d\n", error);
 618                 goto out_free;
 619         }
 620
 621         error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
 622         if (error) {
 623                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
 624                         " due to error %d\n", error);
 625                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
 626                 goto out_free;
 627         }
 628
 629         return 0;
 630 out_free:
 631         kfree(efivars_del_var);
 632         efivars_del_var = NULL;
 633         kfree(efivars_new_var);
 634         efivars_new_var = NULL;
 635         return error;
 636 }
 637
 638 static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
 639                                      unsigned long name_size, void *data)
 640 {
 641         struct efivar_entry *entry = data;
 642
 643         if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
 644                 return 0;
 645
 646         memcpy(entry->var.VariableName, name, name_size);
 647         memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
 648
 649         return 1;
 650 }
 651
 652 static void efivar_update_sysfs_entries(struct work_struct *work)
 653 {
 654         struct efivar_entry *entry;
 655         int err;
 656
 657         /* Add new sysfs entries */
 658         while (1) {
 659                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 660                 if (!entry)
 661                         return;
 662
 663                 err = efivar_init(efivar_update_sysfs_entry, entry,
 664                                   false, &efivar_sysfs_list);
 665                 if (!err)
 666                         break;
 667
 668                 efivar_create_sysfs_entry(entry);
 669         }
 670
 671         kfree(entry);
 672 }
 673
 674 static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
 675                                   unsigned long name_size, void *data)
 676 {
 677         struct efivar_entry *entry;
 678
 679         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 680         if (!entry)
 681                 return -ENOMEM;
 682
 683         memcpy(entry->var.VariableName, name, name_size);
 684         memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
 685
 686         efivar_create_sysfs_entry(entry);
 687
 688         return 0;
 689 }
 690
 691 static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
 692 {
 693         efivar_entry_remove(entry);
 694         efivar_unregister(entry);
 695         return 0;
 696 }
 697
 698 static void efivars_sysfs_exit(void)
 699 {
 700         /* Remove all entries and destroy */
 701         __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
 702
 703         if (efivars_new_var)
 704                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
 705         if (efivars_del_var)
 706                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
 707         kfree(efivars_new_var);
 708         kfree(efivars_del_var);
 709         kset_unregister(efivars_kset);
 710 }
 711
 712 int efivars_sysfs_init(void)
 713 {
 714         struct kobject *parent_kobj = efivars_kobject();
 715         int error = 0;
 716
 717         if (!efi_enabled(EFI_RUNTIME_SERVICES))
 718                 return -ENODEV;
 719
 720         /* No efivars has been registered yet */
 721         if (!parent_kobj)
 722                 return 0;
 723
 724         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 725                EFIVARS_DATE);
 726
 727         efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
 728         if (!efivars_kset) {
 729                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 730                 return -ENOMEM;
 731         }
 732
 733         efivar_init(efivars_sysfs_callback, NULL, true, &efivar_sysfs_list);
 734
 735         error = create_efivars_bin_attributes();
 736         if (error) {
 737                 efivars_sysfs_exit();
 738                 return error;
 739         }
 740
 741         INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
 742
 743         return 0;
 744 }
 745 EXPORT_SYMBOL_GPL(efivars_sysfs_init);
 746
 747 module_init(efivars_sysfs_init);
 748 module_exit(efivars_sysfs_exit);