drivers/firmware/efivars.c

   1 /*
   2  * EFI Variables - 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_unparse()
  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/capability.h>
  69 #include <linux/types.h>
  70 #include <linux/errno.h>
  71 #include <linux/init.h>
  72 #include <linux/mm.h>
  73 #include <linux/module.h>
  74 #include <linux/string.h>
  75 #include <linux/smp.h>
  76 #include <linux/efi.h>
  77 #include <linux/sysfs.h>
  78 #include <linux/kobject.h>
  79 #include <linux/device.h>
  80 #include <linux/slab.h>
  81 #include <linux/pstore.h>
  82
  83 #include <asm/uaccess.h>
  84
  85 #define EFIVARS_VERSION "0.08"
  86 #define EFIVARS_DATE "2004-May-17"
  87
  88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  90 MODULE_LICENSE("GPL");
  91 MODULE_VERSION(EFIVARS_VERSION);
  92
  93 #define DUMP_NAME_LEN 52
  94
  95 static bool efivars_pstore_disable =
  96         IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
  97
  98 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
  99
 100 /*
 101  * The maximum size of VariableName + Data = 1024
 102  * Therefore, it's reasonable to save that much
 103  * space in each part of the structure,
 104  * and we use a page for reading/writing.
 105  */
 106
 107 struct efi_variable {
 108         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 109         efi_guid_t    VendorGuid;
 110         unsigned long DataSize;
 111         __u8          Data[1024];
 112         efi_status_t  Status;
 113         __u32         Attributes;
 114 } __attribute__((packed));
 115
 116
 117 struct efivar_entry {
 118         struct efivars *efivars;
 119         struct efi_variable var;
 120         struct list_head list;
 121         struct kobject kobj;
 122 };
 123
 124 struct efivar_attribute {
 125         struct attribute attr;
 126         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 127         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 128 };
 129
 130 static struct efivars __efivars;
 131
 132 #define PSTORE_EFI_ATTRIBUTES \
 133         (EFI_VARIABLE_NON_VOLATILE | \
 134          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 135          EFI_VARIABLE_RUNTIME_ACCESS)
 136
 137 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 138 struct efivar_attribute efivar_attr_##_name = { \
 139         .attr = {.name = __stringify(_name), .mode = _mode}, \
 140         .show = _show, \
 141         .store = _store, \
 142 };
 143
 144 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 145 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 146
 147 /*
 148  * Prototype for sysfs creation function
 149  */
 150 static int
 151 efivar_create_sysfs_entry(struct efivars *efivars,
 152                           unsigned long variable_name_size,
 153                           efi_char16_t *variable_name,
 154                           efi_guid_t *vendor_guid);
 155
 156 /*
 157  * Prototype for workqueue functions updating sysfs entry
 158  */
 159
 160 static void efivar_update_sysfs_entries(struct work_struct *);
 161 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
 162 static bool efivar_wq_enabled = true;
 163
 164 /* Return the number of unicode characters in data */
 165 static unsigned long
 166 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 167 {
 168         unsigned long length = 0;
 169
 170         while (*s++ != 0 && length < maxlength)
 171                 length++;
 172         return length;
 173 }
 174
 175 static inline unsigned long
 176 utf16_strlen(efi_char16_t *s)
 177 {
 178         return utf16_strnlen(s, ~0UL);
 179 }
 180
 181 /*
 182  * Return the number of bytes is the length of this string
 183  * Note: this is NOT the same as the number of unicode characters
 184  */
 185 static inline unsigned long
 186 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 187 {
 188         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 189 }
 190
 191 static inline int
 192 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 193 {
 194         while (1) {
 195                 if (len == 0)
 196                         return 0;
 197                 if (*a < *b)
 198                         return -1;
 199                 if (*a > *b)
 200                         return 1;
 201                 if (*a == 0) /* implies *b == 0 */
 202                         return 0;
 203                 a++;
 204                 b++;
 205                 len--;
 206         }
 207 }
 208
 209 static bool
 210 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 211                      unsigned long len)
 212 {
 213         struct efi_generic_dev_path *node;
 214         int offset = 0;
 215
 216         node = (struct efi_generic_dev_path *)buffer;
 217
 218         if (len < sizeof(*node))
 219                 return false;
 220
 221         while (offset <= len - sizeof(*node) &&
 222                node->length >= sizeof(*node) &&
 223                 node->length <= len - offset) {
 224                 offset += node->length;
 225
 226                 if ((node->type == EFI_DEV_END_PATH ||
 227                      node->type == EFI_DEV_END_PATH2) &&
 228                     node->sub_type == EFI_DEV_END_ENTIRE)
 229                         return true;
 230
 231                 node = (struct efi_generic_dev_path *)(buffer + offset);
 232         }
 233
 234         /*
 235          * If we're here then either node->length pointed past the end
 236          * of the buffer or we reached the end of the buffer without
 237          * finding a device path end node.
 238          */
 239         return false;
 240 }
 241
 242 static bool
 243 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 244                     unsigned long len)
 245 {
 246         /* An array of 16-bit integers */
 247         if ((len % 2) != 0)
 248                 return false;
 249
 250         return true;
 251 }
 252
 253 static bool
 254 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 255                      unsigned long len)
 256 {
 257         u16 filepathlength;
 258         int i, desclength = 0, namelen;
 259
 260         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 261
 262         /* Either "Boot" or "Driver" followed by four digits of hex */
 263         for (i = match; i < match+4; i++) {
 264                 if (var->VariableName[i] > 127 ||
 265                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 266                         return true;
 267         }
 268
 269         /* Reject it if there's 4 digits of hex and then further content */
 270         if (namelen > match + 4)
 271                 return false;
 272
 273         /* A valid entry must be at least 8 bytes */
 274         if (len < 8)
 275                 return false;
 276
 277         filepathlength = buffer[4] | buffer[5] << 8;
 278
 279         /*
 280          * There's no stored length for the description, so it has to be
 281          * found by hand
 282          */
 283         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 284
 285         /* Each boot entry must have a descriptor */
 286         if (!desclength)
 287                 return false;
 288
 289         /*
 290          * If the sum of the length of the description, the claimed filepath
 291          * length and the original header are greater than the length of the
 292          * variable, it's malformed
 293          */
 294         if ((desclength + filepathlength + 6) > len)
 295                 return false;
 296
 297         /*
 298          * And, finally, check the filepath
 299          */
 300         return validate_device_path(var, match, buffer + desclength + 6,
 301                                     filepathlength);
 302 }
 303
 304 static bool
 305 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 306                 unsigned long len)
 307 {
 308         /* A single 16-bit integer */
 309         if (len != 2)
 310                 return false;
 311
 312         return true;
 313 }
 314
 315 static bool
 316 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 317                       unsigned long len)
 318 {
 319         int i;
 320
 321         for (i = 0; i < len; i++) {
 322                 if (buffer[i] > 127)
 323                         return false;
 324
 325                 if (buffer[i] == 0)
 326                         return true;
 327         }
 328
 329         return false;
 330 }
 331
 332 struct variable_validate {
 333         char *name;
 334         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 335                          unsigned long len);
 336 };
 337
 338 static const struct variable_validate variable_validate[] = {
 339         { "BootNext", validate_uint16 },
 340         { "BootOrder", validate_boot_order },
 341         { "DriverOrder", validate_boot_order },
 342         { "Boot*", validate_load_option },
 343         { "Driver*", validate_load_option },
 344         { "ConIn", validate_device_path },
 345         { "ConInDev", validate_device_path },
 346         { "ConOut", validate_device_path },
 347         { "ConOutDev", validate_device_path },
 348         { "ErrOut", validate_device_path },
 349         { "ErrOutDev", validate_device_path },
 350         { "Timeout", validate_uint16 },
 351         { "Lang", validate_ascii_string },
 352         { "PlatformLang", validate_ascii_string },
 353         { "", NULL },
 354 };
 355
 356 static bool
 357 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 358 {
 359         int i;
 360         u16 *unicode_name = var->VariableName;
 361
 362         for (i = 0; variable_validate[i].validate != NULL; i++) {
 363                 const char *name = variable_validate[i].name;
 364                 int match;
 365
 366                 for (match = 0; ; match++) {
 367                         char c = name[match];
 368                         u16 u = unicode_name[match];
 369
 370                         /* All special variables are plain ascii */
 371                         if (u > 127)
 372                                 return true;
 373
 374                         /* Wildcard in the matching name means we've matched */
 375                         if (c == '*')
 376                                 return variable_validate[i].validate(var,
 377                                                              match, data, len);
 378
 379                         /* Case sensitive match */
 380                         if (c != u)
 381                                 break;
 382
 383                         /* Reached the end of the string while matching */
 384                         if (!c)
 385                                 return variable_validate[i].validate(var,
 386                                                              match, data, len);
 387                 }
 388         }
 389
 390         return true;
 391 }
 392
 393 static efi_status_t
 394 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 395 {
 396         efi_status_t status;
 397
 398         var->DataSize = 1024;
 399         status = efivars->ops->get_variable(var->VariableName,
 400                                             &var->VendorGuid,
 401                                             &var->Attributes,
 402                                             &var->DataSize,
 403                                             var->Data);
 404         return status;
 405 }
 406
 407 static efi_status_t
 408 get_var_data(struct efivars *efivars, struct efi_variable *var)
 409 {
 410         efi_status_t status;
 411         unsigned long flags;
 412
 413         spin_lock_irqsave(&efivars->lock, flags);
 414         status = get_var_data_locked(efivars, var);
 415         spin_unlock_irqrestore(&efivars->lock, flags);
 416
 417         if (status != EFI_SUCCESS) {
 418                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 419                         status);
 420         }
 421         return status;
 422 }
 423
 424 static efi_status_t
 425 check_var_size_locked(struct efivars *efivars, u32 attributes,
 426                         unsigned long size)
 427 {
 428         const struct efivar_operations *fops = efivars->ops;
 429
 430         if (!efivars->ops->query_variable_store)
 431                 return EFI_UNSUPPORTED;
 432
 433         return fops->query_variable_store(attributes, size);
 434 }
 435
 436 static ssize_t
 437 efivar_guid_read(struct efivar_entry *entry, char *buf)
 438 {
 439         struct efi_variable *var = &entry->var;
 440         char *str = buf;
 441
 442         if (!entry || !buf)
 443                 return 0;
 444
 445         efi_guid_unparse(&var->VendorGuid, str);
 446         str += strlen(str);
 447         str += sprintf(str, "\n");
 448
 449         return str - buf;
 450 }
 451
 452 static ssize_t
 453 efivar_attr_read(struct efivar_entry *entry, char *buf)
 454 {
 455         struct efi_variable *var = &entry->var;
 456         char *str = buf;
 457         efi_status_t status;
 458
 459         if (!entry || !buf)
 460                 return -EINVAL;
 461
 462         status = get_var_data(entry->efivars, var);
 463         if (status != EFI_SUCCESS)
 464                 return -EIO;
 465
 466         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 467                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 468         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 469                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 470         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 471                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 472         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 473                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 474         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 475                 str += sprintf(str,
 476                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 477         if (var->Attributes &
 478                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 479                 str += sprintf(str,
 480                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 481         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 482                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 483         return str - buf;
 484 }
 485
 486 static ssize_t
 487 efivar_size_read(struct efivar_entry *entry, char *buf)
 488 {
 489         struct efi_variable *var = &entry->var;
 490         char *str = buf;
 491         efi_status_t status;
 492
 493         if (!entry || !buf)
 494                 return -EINVAL;
 495
 496         status = get_var_data(entry->efivars, var);
 497         if (status != EFI_SUCCESS)
 498                 return -EIO;
 499
 500         str += sprintf(str, "0x%lx\n", var->DataSize);
 501         return str - buf;
 502 }
 503
 504 static ssize_t
 505 efivar_data_read(struct efivar_entry *entry, char *buf)
 506 {
 507         struct efi_variable *var = &entry->var;
 508         efi_status_t status;
 509
 510         if (!entry || !buf)
 511                 return -EINVAL;
 512
 513         status = get_var_data(entry->efivars, var);
 514         if (status != EFI_SUCCESS)
 515                 return -EIO;
 516
 517         memcpy(buf, var->Data, var->DataSize);
 518         return var->DataSize;
 519 }
 520 /*
 521  * We allow each variable to be edited via rewriting the
 522  * entire efi variable structure.
 523  */
 524 static ssize_t
 525 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 526 {
 527         struct efi_variable *new_var, *var = &entry->var;
 528         struct efivars *efivars = entry->efivars;
 529         efi_status_t status = EFI_NOT_FOUND;
 530
 531         if (count != sizeof(struct efi_variable))
 532                 return -EINVAL;
 533
 534         new_var = (struct efi_variable *)buf;
 535         /*
 536          * If only updating the variable data, then the name
 537          * and guid should remain the same
 538          */
 539         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 540                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 541                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 542                 return -EINVAL;
 543         }
 544
 545         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 546                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 547                 return -EINVAL;
 548         }
 549
 550         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 551             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 552                 printk(KERN_ERR "efivars: Malformed variable content\n");
 553                 return -EINVAL;
 554         }
 555
 556         spin_lock_irq(&efivars->lock);
 557
 558         status = check_var_size_locked(efivars, new_var->Attributes,
 559                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 560
 561         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 562                 status = efivars->ops->set_variable(new_var->VariableName,
 563                                                     &new_var->VendorGuid,
 564                                                     new_var->Attributes,
 565                                                     new_var->DataSize,
 566                                                     new_var->Data);
 567
 568         spin_unlock_irq(&efivars->lock);
 569
 570         if (status != EFI_SUCCESS) {
 571                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 572                         status);
 573                 return -EIO;
 574         }
 575
 576         memcpy(&entry->var, new_var, count);
 577         return count;
 578 }
 579
 580 static ssize_t
 581 efivar_show_raw(struct efivar_entry *entry, char *buf)
 582 {
 583         struct efi_variable *var = &entry->var;
 584         efi_status_t status;
 585
 586         if (!entry || !buf)
 587                 return 0;
 588
 589         status = get_var_data(entry->efivars, var);
 590         if (status != EFI_SUCCESS)
 591                 return -EIO;
 592
 593         memcpy(buf, var, sizeof(*var));
 594         return sizeof(*var);
 595 }
 596
 597 /*
 598  * Generic read/write functions that call the specific functions of
 599  * the attributes...
 600  */
 601 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 602                                 char *buf)
 603 {
 604         struct efivar_entry *var = to_efivar_entry(kobj);
 605         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 606         ssize_t ret = -EIO;
 607
 608         if (!capable(CAP_SYS_ADMIN))
 609                 return -EACCES;
 610
 611         if (efivar_attr->show) {
 612                 ret = efivar_attr->show(var, buf);
 613         }
 614         return ret;
 615 }
 616
 617 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 618                                 const char *buf, size_t count)
 619 {
 620         struct efivar_entry *var = to_efivar_entry(kobj);
 621         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 622         ssize_t ret = -EIO;
 623
 624         if (!capable(CAP_SYS_ADMIN))
 625                 return -EACCES;
 626
 627         if (efivar_attr->store)
 628                 ret = efivar_attr->store(var, buf, count);
 629
 630         return ret;
 631 }
 632
 633 static const struct sysfs_ops efivar_attr_ops = {
 634         .show = efivar_attr_show,
 635         .store = efivar_attr_store,
 636 };
 637
 638 static void efivar_release(struct kobject *kobj)
 639 {
 640         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 641         kfree(var);
 642 }
 643
 644 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 645 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 646 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 647 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 648 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 649
 650 static struct attribute *def_attrs[] = {
 651         &efivar_attr_guid.attr,
 652         &efivar_attr_size.attr,
 653         &efivar_attr_attributes.attr,
 654         &efivar_attr_data.attr,
 655         &efivar_attr_raw_var.attr,
 656         NULL,
 657 };
 658
 659 static struct kobj_type efivar_ktype = {
 660         .release = efivar_release,
 661         .sysfs_ops = &efivar_attr_ops,
 662         .default_attrs = def_attrs,
 663 };
 664
 665 static inline void
 666 efivar_unregister(struct efivar_entry *var)
 667 {
 668         kobject_put(&var->kobj);
 669 }
 670
 671 static int efi_status_to_err(efi_status_t status)
 672 {
 673         int err;
 674
 675         switch (status) {
 676         case EFI_INVALID_PARAMETER:
 677                 err = -EINVAL;
 678                 break;
 679         case EFI_OUT_OF_RESOURCES:
 680                 err = -ENOSPC;
 681                 break;
 682         case EFI_DEVICE_ERROR:
 683                 err = -EIO;
 684                 break;
 685         case EFI_WRITE_PROTECTED:
 686                 err = -EROFS;
 687                 break;
 688         case EFI_SECURITY_VIOLATION:
 689                 err = -EACCES;
 690                 break;
 691         case EFI_NOT_FOUND:
 692                 err = -ENOENT;
 693                 break;
 694         default:
 695                 err = -EINVAL;
 696         }
 697
 698         return err;
 699 }
 700
 701 #ifdef CONFIG_EFI_VARS_PSTORE
 702
 703 static int efi_pstore_open(struct pstore_info *psi)
 704 {
 705         struct efivars *efivars = psi->data;
 706
 707         spin_lock_irq(&efivars->lock);
 708         efivars->walk_entry = list_first_entry(&efivars->list,
 709                                                struct efivar_entry, list);
 710         return 0;
 711 }
 712
 713 static int efi_pstore_close(struct pstore_info *psi)
 714 {
 715         struct efivars *efivars = psi->data;
 716
 717         spin_unlock_irq(&efivars->lock);
 718         return 0;
 719 }
 720
 721 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 722                                struct timespec *timespec,
 723                                char **buf, struct pstore_info *psi)
 724 {
 725         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 726         struct efivars *efivars = psi->data;
 727         char name[DUMP_NAME_LEN];
 728         int i;
 729         unsigned int part, size;
 730         unsigned long time;
 731
 732         while (&efivars->walk_entry->list != &efivars->list) {
 733                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 734                                  vendor)) {
 735                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 736                                 name[i] = efivars->walk_entry->var.VariableName[i];
 737                         }
 738                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 739                                 *id = part;
 740                                 timespec->tv_sec = time;
 741                                 timespec->tv_nsec = 0;
 742                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 743                                 size = efivars->walk_entry->var.DataSize;
 744                                 *buf = kmalloc(size, GFP_KERNEL);
 745                                 if (*buf == NULL)
 746                                         return -ENOMEM;
 747                                 memcpy(*buf, efivars->walk_entry->var.Data,
 748                                        size);
 749                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 750                                                    struct efivar_entry, list);
 751                                 return size;
 752                         }
 753                 }
 754                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 755                                                  struct efivar_entry, list);
 756         }
 757         return 0;
 758 }
 759
 760 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
 761                 unsigned int part, size_t size, struct pstore_info *psi)
 762 {
 763         char name[DUMP_NAME_LEN];
 764         char stub_name[DUMP_NAME_LEN];
 765         efi_char16_t efi_name[DUMP_NAME_LEN];
 766         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 767         struct efivars *efivars = psi->data;
 768         struct efivar_entry *entry, *found = NULL;
 769         int i, ret = 0;
 770         efi_status_t status = EFI_NOT_FOUND;
 771         unsigned long flags;
 772
 773         sprintf(stub_name, "dump-type%u-%u-", type, part);
 774         sprintf(name, "%s%lu", stub_name, get_seconds());
 775
 776         spin_lock_irqsave(&efivars->lock, flags);
 777
 778         if (size) {
 779                 /*
 780                  * Check if there is a space enough to log.
 781                  * size: a size of logging data
 782                  * DUMP_NAME_LEN * 2: a maximum size of variable name
 783                  */
 784
 785                 status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
 786                                                size + DUMP_NAME_LEN * 2);
 787
 788                 if (status) {
 789                         spin_unlock_irqrestore(&efivars->lock, flags);
 790                         *id = part;
 791                         return -ENOSPC;
 792                 }
 793         }
 794
 795         for (i = 0; i < DUMP_NAME_LEN; i++)
 796                 efi_name[i] = stub_name[i];
 797
 798         /*
 799          * Clean up any entries with the same name
 800          */
 801
 802         list_for_each_entry(entry, &efivars->list, list) {
 803                 get_var_data_locked(efivars, &entry->var);
 804
 805                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
 806                         continue;
 807                 if (utf16_strncmp(entry->var.VariableName, efi_name,
 808                                   utf16_strlen(efi_name)))
 809                         continue;
 810                 /* Needs to be a prefix */
 811                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 812                         continue;
 813
 814                 /* found */
 815                 found = entry;
 816                 efivars->ops->set_variable(entry->var.VariableName,
 817                                            &entry->var.VendorGuid,
 818                                            PSTORE_EFI_ATTRIBUTES,
 819                                            0, NULL);
 820         }
 821
 822         if (found)
 823                 list_del(&found->list);
 824
 825         for (i = 0; i < DUMP_NAME_LEN; i++)
 826                 efi_name[i] = name[i];
 827
 828         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 829                                    size, psi->buf);
 830
 831         spin_unlock_irqrestore(&efivars->lock, flags);
 832
 833         if (found)
 834                 efivar_unregister(found);
 835
 836         if (efivar_wq_enabled)
 837                 schedule_work(&efivar_work);
 838
 839         *id = part;
 840         return ret;
 841 };
 842
 843 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 844                             struct pstore_info *psi)
 845 {
 846         efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
 847
 848         return 0;
 849 }
 850
 851 static struct pstore_info efi_pstore_info = {
 852         .owner          = THIS_MODULE,
 853         .name           = "efi",
 854         .open           = efi_pstore_open,
 855         .close          = efi_pstore_close,
 856         .read           = efi_pstore_read,
 857         .write          = efi_pstore_write,
 858         .erase          = efi_pstore_erase,
 859 };
 860
 861 static void efivar_pstore_register(struct efivars *efivars)
 862 {
 863         efivars->efi_pstore_info = efi_pstore_info;
 864         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
 865         if (efivars->efi_pstore_info.buf) {
 866                 efivars->efi_pstore_info.bufsize = 1024;
 867                 efivars->efi_pstore_info.data = efivars;
 868                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
 869                 pstore_register(&efivars->efi_pstore_info);
 870         }
 871 }
 872 #else
 873 static void efivar_pstore_register(struct efivars *efivars)
 874 {
 875         return;
 876 }
 877 #endif
 878
 879 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 880                              struct bin_attribute *bin_attr,
 881                              char *buf, loff_t pos, size_t count)
 882 {
 883         struct efi_variable *new_var = (struct efi_variable *)buf;
 884         struct efivars *efivars = bin_attr->private;
 885         struct efivar_entry *search_efivar, *n;
 886         unsigned long strsize1, strsize2;
 887         efi_status_t status = EFI_NOT_FOUND;
 888         int found = 0;
 889
 890         if (!capable(CAP_SYS_ADMIN))
 891                 return -EACCES;
 892
 893         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 894             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 895                 printk(KERN_ERR "efivars: Malformed variable content\n");
 896                 return -EINVAL;
 897         }
 898
 899         spin_lock_irq(&efivars->lock);
 900
 901         /*
 902          * Does this variable already exist?
 903          */
 904         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 905                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 906                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
 907                 if (strsize1 == strsize2 &&
 908                         !memcmp(&(search_efivar->var.VariableName),
 909                                 new_var->VariableName, strsize1) &&
 910                         !efi_guidcmp(search_efivar->var.VendorGuid,
 911                                 new_var->VendorGuid)) {
 912                         found = 1;
 913                         break;
 914                 }
 915         }
 916         if (found) {
 917                 spin_unlock_irq(&efivars->lock);
 918                 return -EINVAL;
 919         }
 920
 921         status = check_var_size_locked(efivars, new_var->Attributes,
 922                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 923
 924         if (status && status != EFI_UNSUPPORTED) {
 925                 spin_unlock_irq(&efivars->lock);
 926                 return efi_status_to_err(status);
 927         }
 928
 929         /* now *really* create the variable via EFI */
 930         status = efivars->ops->set_variable(new_var->VariableName,
 931                                             &new_var->VendorGuid,
 932                                             new_var->Attributes,
 933                                             new_var->DataSize,
 934                                             new_var->Data);
 935
 936         if (status != EFI_SUCCESS) {
 937                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 938                         status);
 939                 spin_unlock_irq(&efivars->lock);
 940                 return -EIO;
 941         }
 942         spin_unlock_irq(&efivars->lock);
 943
 944         /* Create the entry in sysfs.  Locking is not required here */
 945         status = efivar_create_sysfs_entry(efivars,
 946                                            utf16_strsize(new_var->VariableName,
 947                                                          1024),
 948                                            new_var->VariableName,
 949                                            &new_var->VendorGuid);
 950         if (status) {
 951                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 952         }
 953         return count;
 954 }
 955
 956 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 957                              struct bin_attribute *bin_attr,
 958                              char *buf, loff_t pos, size_t count)
 959 {
 960         struct efi_variable *del_var = (struct efi_variable *)buf;
 961         struct efivars *efivars = bin_attr->private;
 962         struct efivar_entry *search_efivar, *n;
 963         unsigned long strsize1, strsize2;
 964         efi_status_t status = EFI_NOT_FOUND;
 965         int found = 0;
 966
 967         if (!capable(CAP_SYS_ADMIN))
 968                 return -EACCES;
 969
 970         spin_lock_irq(&efivars->lock);
 971
 972         /*
 973          * Does this variable already exist?
 974          */
 975         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 976                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 977                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
 978                 if (strsize1 == strsize2 &&
 979                         !memcmp(&(search_efivar->var.VariableName),
 980                                 del_var->VariableName, strsize1) &&
 981                         !efi_guidcmp(search_efivar->var.VendorGuid,
 982                                 del_var->VendorGuid)) {
 983                         found = 1;
 984                         break;
 985                 }
 986         }
 987         if (!found) {
 988                 spin_unlock_irq(&efivars->lock);
 989                 return -EINVAL;
 990         }
 991         /* force the Attributes/DataSize to 0 to ensure deletion */
 992         del_var->Attributes = 0;
 993         del_var->DataSize = 0;
 994
 995         status = efivars->ops->set_variable(del_var->VariableName,
 996                                             &del_var->VendorGuid,
 997                                             del_var->Attributes,
 998                                             del_var->DataSize,
 999                                             del_var->Data);
1000
1001         if (status != EFI_SUCCESS) {
1002                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1003                         status);
1004                 spin_unlock_irq(&efivars->lock);
1005                 return -EIO;
1006         }
1007         list_del(&search_efivar->list);
1008         /* We need to release this lock before unregistering. */
1009         spin_unlock_irq(&efivars->lock);
1010         efivar_unregister(search_efivar);
1011
1012         /* It's dead Jim.... */
1013         return count;
1014 }
1015
1016 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1017 {
1018         struct efivar_entry *entry, *n;
1019         struct efivars *efivars = &__efivars;
1020         unsigned long strsize1, strsize2;
1021         bool found = false;
1022
1023         strsize1 = utf16_strsize(variable_name, 1024);
1024         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1025                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1026                 if (strsize1 == strsize2 &&
1027                         !memcmp(variable_name, &(entry->var.VariableName),
1028                                 strsize2) &&
1029                         !efi_guidcmp(entry->var.VendorGuid,
1030                                 *vendor)) {
1031                         found = true;
1032                         break;
1033                 }
1034         }
1035         return found;
1036 }
1037
1038 /*
1039  * Returns the size of variable_name, in bytes, including the
1040  * terminating NULL character, or variable_name_size if no NULL
1041  * character is found among the first variable_name_size bytes.
1042  */
1043 static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1044                                        unsigned long variable_name_size)
1045 {
1046         unsigned long len;
1047         efi_char16_t c;
1048
1049         /*
1050          * The variable name is, by definition, a NULL-terminated
1051          * string, so make absolutely sure that variable_name_size is
1052          * the value we expect it to be. If not, return the real size.
1053          */
1054         for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1055                 c = variable_name[(len / sizeof(c)) - 1];
1056                 if (!c)
1057                         break;
1058         }
1059
1060         return min(len, variable_name_size);
1061 }
1062
1063 static void efivar_update_sysfs_entries(struct work_struct *work)
1064 {
1065         struct efivars *efivars = &__efivars;
1066         efi_guid_t vendor;
1067         efi_char16_t *variable_name;
1068         unsigned long variable_name_size = 1024;
1069         efi_status_t status = EFI_NOT_FOUND;
1070         bool found;
1071
1072         /* Add new sysfs entries */
1073         while (1) {
1074                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1075                 if (!variable_name) {
1076                         pr_err("efivars: Memory allocation failed.\n");
1077                         return;
1078                 }
1079
1080                 spin_lock_irq(&efivars->lock);
1081                 found = false;
1082                 while (1) {
1083                         variable_name_size = 1024;
1084                         status = efivars->ops->get_next_variable(
1085                                                         &variable_name_size,
1086                                                         variable_name,
1087                                                         &vendor);
1088                         if (status != EFI_SUCCESS) {
1089                                 break;
1090                         } else {
1091                                 if (!variable_is_present(variable_name,
1092                                     &vendor)) {
1093                                         found = true;
1094                                         break;
1095                                 }
1096                         }
1097                 }
1098                 spin_unlock_irq(&efivars->lock);
1099
1100                 if (!found) {
1101                         kfree(variable_name);
1102                         break;
1103                 } else {
1104                         variable_name_size = var_name_strnsize(variable_name,
1105                                                                variable_name_size);
1106                         efivar_create_sysfs_entry(efivars,
1107                                                   variable_name_size,
1108                                                   variable_name, &vendor);
1109                 }
1110         }
1111 }
1112
1113 /*
1114  * Let's not leave out systab information that snuck into
1115  * the efivars driver
1116  */
1117 static ssize_t systab_show(struct kobject *kobj,
1118                            struct kobj_attribute *attr, char *buf)
1119 {
1120         char *str = buf;
1121
1122         if (!kobj || !buf)
1123                 return -EINVAL;
1124
1125         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1126                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1127         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1128                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1129         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1130                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1131         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1132                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1133         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1134                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1135         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1136                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1137         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1138                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1139
1140         return str - buf;
1141 }
1142
1143 static struct kobj_attribute efi_attr_systab =
1144                         __ATTR(systab, 0400, systab_show, NULL);
1145
1146 static struct attribute *efi_subsys_attrs[] = {
1147         &efi_attr_systab.attr,
1148         NULL,   /* maybe more in the future? */
1149 };
1150
1151 static struct attribute_group efi_subsys_attr_group = {
1152         .attrs = efi_subsys_attrs,
1153 };
1154
1155 static struct kobject *efi_kobj;
1156
1157 /*
1158  * efivar_create_sysfs_entry()
1159  * Requires:
1160  *    variable_name_size = number of bytes required to hold
1161  *                         variable_name (not counting the NULL
1162  *                         character at the end.
1163  *    efivars->lock is not held on entry or exit.
1164  * Returns 1 on failure, 0 on success
1165  */
1166 static int
1167 efivar_create_sysfs_entry(struct efivars *efivars,
1168                           unsigned long variable_name_size,
1169                           efi_char16_t *variable_name,
1170                           efi_guid_t *vendor_guid)
1171 {
1172         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1173         char *short_name;
1174         struct efivar_entry *new_efivar;
1175
1176         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1177         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1178
1179         if (!short_name || !new_efivar)  {
1180                 kfree(short_name);
1181                 kfree(new_efivar);
1182                 return 1;
1183         }
1184
1185         new_efivar->efivars = efivars;
1186         memcpy(new_efivar->var.VariableName, variable_name,
1187                 variable_name_size);
1188         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1189
1190         /* Convert Unicode to normal chars (assume top bits are 0),
1191            ala UTF-8 */
1192         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1193                 short_name[i] = variable_name[i] & 0xFF;
1194         }
1195         /* This is ugly, but necessary to separate one vendor's
1196            private variables from another's.         */
1197
1198         *(short_name + strlen(short_name)) = '-';
1199         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1200
1201         new_efivar->kobj.kset = efivars->kset;
1202         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1203                                  "%s", short_name);
1204         if (i) {
1205                 kfree(short_name);
1206                 kfree(new_efivar);
1207                 return 1;
1208         }
1209
1210         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1211         kfree(short_name);
1212         short_name = NULL;
1213
1214         spin_lock_irq(&efivars->lock);
1215         list_add(&new_efivar->list, &efivars->list);
1216         spin_unlock_irq(&efivars->lock);
1217
1218         return 0;
1219 }
1220
1221 static int
1222 create_efivars_bin_attributes(struct efivars *efivars)
1223 {
1224         struct bin_attribute *attr;
1225         int error;
1226
1227         /* new_var */
1228         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1229         if (!attr)
1230                 return -ENOMEM;
1231
1232         attr->attr.name = "new_var";
1233         attr->attr.mode = 0200;
1234         attr->write = efivar_create;
1235         attr->private = efivars;
1236         efivars->new_var = attr;
1237
1238         /* del_var */
1239         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1240         if (!attr) {
1241                 error = -ENOMEM;
1242                 goto out_free;
1243         }
1244         attr->attr.name = "del_var";
1245         attr->attr.mode = 0200;
1246         attr->write = efivar_delete;
1247         attr->private = efivars;
1248         efivars->del_var = attr;
1249
1250         sysfs_bin_attr_init(efivars->new_var);
1251         sysfs_bin_attr_init(efivars->del_var);
1252
1253         /* Register */
1254         error = sysfs_create_bin_file(&efivars->kset->kobj,
1255                                       efivars->new_var);
1256         if (error) {
1257                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1258                         " due to error %d\n", error);
1259                 goto out_free;
1260         }
1261         error = sysfs_create_bin_file(&efivars->kset->kobj,
1262                                       efivars->del_var);
1263         if (error) {
1264                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1265                         " due to error %d\n", error);
1266                 sysfs_remove_bin_file(&efivars->kset->kobj,
1267                                       efivars->new_var);
1268                 goto out_free;
1269         }
1270
1271         return 0;
1272 out_free:
1273         kfree(efivars->del_var);
1274         efivars->del_var = NULL;
1275         kfree(efivars->new_var);
1276         efivars->new_var = NULL;
1277         return error;
1278 }
1279
1280 void unregister_efivars(struct efivars *efivars)
1281 {
1282         struct efivar_entry *entry, *n;
1283
1284         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1285                 spin_lock_irq(&efivars->lock);
1286                 list_del(&entry->list);
1287                 spin_unlock_irq(&efivars->lock);
1288                 efivar_unregister(entry);
1289         }
1290         if (efivars->new_var)
1291                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1292         if (efivars->del_var)
1293                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1294         kfree(efivars->new_var);
1295         kfree(efivars->del_var);
1296         kset_unregister(efivars->kset);
1297 }
1298 EXPORT_SYMBOL_GPL(unregister_efivars);
1299
1300 /*
1301  * Print a warning when duplicate EFI variables are encountered and
1302  * disable the sysfs workqueue since the firmware is buggy.
1303  */
1304 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1305                              unsigned long len16)
1306 {
1307         size_t i, len8 = len16 / sizeof(efi_char16_t);
1308         char *s8;
1309
1310         /*
1311          * Disable the workqueue since the algorithm it uses for
1312          * detecting new variables won't work with this buggy
1313          * implementation of GetNextVariableName().
1314          */
1315         efivar_wq_enabled = false;
1316
1317         s8 = kzalloc(len8, GFP_KERNEL);
1318         if (!s8)
1319                 return;
1320
1321         for (i = 0; i < len8; i++)
1322                 s8[i] = s16[i];
1323
1324         printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
1325                s8, vendor_guid);
1326         kfree(s8);
1327 }
1328
1329 int register_efivars(struct efivars *efivars,
1330                      const struct efivar_operations *ops,
1331                      struct kobject *parent_kobj)
1332 {
1333         efi_status_t status = EFI_NOT_FOUND;
1334         efi_guid_t vendor_guid;
1335         efi_char16_t *variable_name;
1336         unsigned long variable_name_size = 1024;
1337         int error = 0;
1338
1339         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1340         if (!variable_name) {
1341                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1342                 return -ENOMEM;
1343         }
1344
1345         spin_lock_init(&efivars->lock);
1346         INIT_LIST_HEAD(&efivars->list);
1347         efivars->ops = ops;
1348
1349         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1350         if (!efivars->kset) {
1351                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1352                 error = -ENOMEM;
1353                 goto out;
1354         }
1355
1356         /*
1357          * Per EFI spec, the maximum storage allocated for both
1358          * the variable name and variable data is 1024 bytes.
1359          */
1360
1361         do {
1362                 variable_name_size = 1024;
1363
1364                 status = ops->get_next_variable(&variable_name_size,
1365                                                 variable_name,
1366                                                 &vendor_guid);
1367                 switch (status) {
1368                 case EFI_SUCCESS:
1369                         variable_name_size = var_name_strnsize(variable_name,
1370                                                                variable_name_size);
1371
1372                         /*
1373                          * Some firmware implementations return the
1374                          * same variable name on multiple calls to
1375                          * get_next_variable(). Terminate the loop
1376                          * immediately as there is no guarantee that
1377                          * we'll ever see a different variable name,
1378                          * and may end up looping here forever.
1379                          */
1380                         if (variable_is_present(variable_name, &vendor_guid)) {
1381                                 dup_variable_bug(variable_name, &vendor_guid,
1382                                                  variable_name_size);
1383                                 status = EFI_NOT_FOUND;
1384                                 break;
1385                         }
1386
1387                         efivar_create_sysfs_entry(efivars,
1388                                                   variable_name_size,
1389                                                   variable_name,
1390                                                   &vendor_guid);
1391                         break;
1392                 case EFI_NOT_FOUND:
1393                         break;
1394                 default:
1395                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1396                                 status);
1397                         status = EFI_NOT_FOUND;
1398                         break;
1399                 }
1400         } while (status != EFI_NOT_FOUND);
1401
1402         error = create_efivars_bin_attributes(efivars);
1403         if (error)
1404                 unregister_efivars(efivars);
1405
1406         if (!efivars_pstore_disable)
1407                 efivar_pstore_register(efivars);
1408
1409 out:
1410         kfree(variable_name);
1411
1412         return error;
1413 }
1414 EXPORT_SYMBOL_GPL(register_efivars);
1415
1416 static struct efivar_operations ops;
1417
1418 /*
1419  * For now we register the efi subsystem with the firmware subsystem
1420  * and the vars subsystem with the efi subsystem.  In the future, it
1421  * might make sense to split off the efi subsystem into its own
1422  * driver, but for now only efivars will register with it, so just
1423  * include it here.
1424  */
1425
1426 static int __init
1427 efivars_init(void)
1428 {
1429         int error = 0;
1430
1431         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1432                EFIVARS_DATE);
1433
1434         if (!efi_enabled(EFI_RUNTIME_SERVICES))
1435                 return 0;
1436
1437         /* For now we'll register the efi directory at /sys/firmware/efi */
1438         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1439         if (!efi_kobj) {
1440                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1441                 return -ENOMEM;
1442         }
1443
1444         ops.get_variable = efi.get_variable;
1445         ops.set_variable = efi.set_variable;
1446         ops.get_next_variable = efi.get_next_variable;
1447         ops.query_variable_store = efi_query_variable_store;
1448         error = register_efivars(&__efivars, &ops, efi_kobj);
1449         if (error)
1450                 goto err_put;
1451
1452         /* Don't forget the systab entry */
1453         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1454         if (error) {
1455                 printk(KERN_ERR
1456                        "efivars: Sysfs attribute export failed with error %d.\n",
1457                        error);
1458                 goto err_unregister;
1459         }
1460
1461         return 0;
1462
1463 err_unregister:
1464         unregister_efivars(&__efivars);
1465 err_put:
1466         kobject_put(efi_kobj);
1467         return error;
1468 }
1469
1470 static void __exit
1471 efivars_exit(void)
1472 {
1473         cancel_work_sync(&efivar_work);
1474
1475         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1476                 unregister_efivars(&__efivars);
1477                 kobject_put(efi_kobj);
1478         }
1479 }
1480
1481 module_init(efivars_init);
1482 module_exit(efivars_exit);
1483