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         u64 storage_size, remaining_size, max_size;
 429         efi_status_t status;
 430         const struct efivar_operations *fops = efivars->ops;
 431
 432         if (!efivars->ops->query_variable_info)
 433                 return EFI_UNSUPPORTED;
 434
 435         status = fops->query_variable_info(attributes, &storage_size,
 436                                            &remaining_size, &max_size);
 437
 438         if (status != EFI_SUCCESS)
 439                 return status;
 440
 441         if (!storage_size || size > remaining_size || size > max_size ||
 442             (remaining_size - size) < (storage_size / 2))
 443                 return EFI_OUT_OF_RESOURCES;
 444
 445         return status;
 446 }
 447
 448 static ssize_t
 449 efivar_guid_read(struct efivar_entry *entry, char *buf)
 450 {
 451         struct efi_variable *var = &entry->var;
 452         char *str = buf;
 453
 454         if (!entry || !buf)
 455                 return 0;
 456
 457         efi_guid_unparse(&var->VendorGuid, str);
 458         str += strlen(str);
 459         str += sprintf(str, "\n");
 460
 461         return str - buf;
 462 }
 463
 464 static ssize_t
 465 efivar_attr_read(struct efivar_entry *entry, char *buf)
 466 {
 467         struct efi_variable *var = &entry->var;
 468         char *str = buf;
 469         efi_status_t status;
 470
 471         if (!entry || !buf)
 472                 return -EINVAL;
 473
 474         status = get_var_data(entry->efivars, var);
 475         if (status != EFI_SUCCESS)
 476                 return -EIO;
 477
 478         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 479                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 480         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 481                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 482         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 483                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 484         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 485                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 486         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 487                 str += sprintf(str,
 488                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 489         if (var->Attributes &
 490                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 491                 str += sprintf(str,
 492                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 493         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 494                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 495         return str - buf;
 496 }
 497
 498 static ssize_t
 499 efivar_size_read(struct efivar_entry *entry, char *buf)
 500 {
 501         struct efi_variable *var = &entry->var;
 502         char *str = buf;
 503         efi_status_t status;
 504
 505         if (!entry || !buf)
 506                 return -EINVAL;
 507
 508         status = get_var_data(entry->efivars, var);
 509         if (status != EFI_SUCCESS)
 510                 return -EIO;
 511
 512         str += sprintf(str, "0x%lx\n", var->DataSize);
 513         return str - buf;
 514 }
 515
 516 static ssize_t
 517 efivar_data_read(struct efivar_entry *entry, char *buf)
 518 {
 519         struct efi_variable *var = &entry->var;
 520         efi_status_t status;
 521
 522         if (!entry || !buf)
 523                 return -EINVAL;
 524
 525         status = get_var_data(entry->efivars, var);
 526         if (status != EFI_SUCCESS)
 527                 return -EIO;
 528
 529         memcpy(buf, var->Data, var->DataSize);
 530         return var->DataSize;
 531 }
 532 /*
 533  * We allow each variable to be edited via rewriting the
 534  * entire efi variable structure.
 535  */
 536 static ssize_t
 537 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 538 {
 539         struct efi_variable *new_var, *var = &entry->var;
 540         struct efivars *efivars = entry->efivars;
 541         efi_status_t status = EFI_NOT_FOUND;
 542
 543         if (count != sizeof(struct efi_variable))
 544                 return -EINVAL;
 545
 546         new_var = (struct efi_variable *)buf;
 547         /*
 548          * If only updating the variable data, then the name
 549          * and guid should remain the same
 550          */
 551         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 552                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 553                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 554                 return -EINVAL;
 555         }
 556
 557         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 558                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 559                 return -EINVAL;
 560         }
 561
 562         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 563             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 564                 printk(KERN_ERR "efivars: Malformed variable content\n");
 565                 return -EINVAL;
 566         }
 567
 568         spin_lock_irq(&efivars->lock);
 569
 570         status = check_var_size_locked(efivars, new_var->Attributes,
 571                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 572
 573         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 574                 status = efivars->ops->set_variable(new_var->VariableName,
 575                                                     &new_var->VendorGuid,
 576                                                     new_var->Attributes,
 577                                                     new_var->DataSize,
 578                                                     new_var->Data);
 579
 580         spin_unlock_irq(&efivars->lock);
 581
 582         if (status != EFI_SUCCESS) {
 583                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 584                         status);
 585                 return -EIO;
 586         }
 587
 588         memcpy(&entry->var, new_var, count);
 589         return count;
 590 }
 591
 592 static ssize_t
 593 efivar_show_raw(struct efivar_entry *entry, char *buf)
 594 {
 595         struct efi_variable *var = &entry->var;
 596         efi_status_t status;
 597
 598         if (!entry || !buf)
 599                 return 0;
 600
 601         status = get_var_data(entry->efivars, var);
 602         if (status != EFI_SUCCESS)
 603                 return -EIO;
 604
 605         memcpy(buf, var, sizeof(*var));
 606         return sizeof(*var);
 607 }
 608
 609 /*
 610  * Generic read/write functions that call the specific functions of
 611  * the attributes...
 612  */
 613 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 614                                 char *buf)
 615 {
 616         struct efivar_entry *var = to_efivar_entry(kobj);
 617         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 618         ssize_t ret = -EIO;
 619
 620         if (!capable(CAP_SYS_ADMIN))
 621                 return -EACCES;
 622
 623         if (efivar_attr->show) {
 624                 ret = efivar_attr->show(var, buf);
 625         }
 626         return ret;
 627 }
 628
 629 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 630                                 const char *buf, size_t count)
 631 {
 632         struct efivar_entry *var = to_efivar_entry(kobj);
 633         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 634         ssize_t ret = -EIO;
 635
 636         if (!capable(CAP_SYS_ADMIN))
 637                 return -EACCES;
 638
 639         if (efivar_attr->store)
 640                 ret = efivar_attr->store(var, buf, count);
 641
 642         return ret;
 643 }
 644
 645 static const struct sysfs_ops efivar_attr_ops = {
 646         .show = efivar_attr_show,
 647         .store = efivar_attr_store,
 648 };
 649
 650 static void efivar_release(struct kobject *kobj)
 651 {
 652         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 653         kfree(var);
 654 }
 655
 656 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 657 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 658 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 659 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 660 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 661
 662 static struct attribute *def_attrs[] = {
 663         &efivar_attr_guid.attr,
 664         &efivar_attr_size.attr,
 665         &efivar_attr_attributes.attr,
 666         &efivar_attr_data.attr,
 667         &efivar_attr_raw_var.attr,
 668         NULL,
 669 };
 670
 671 static struct kobj_type efivar_ktype = {
 672         .release = efivar_release,
 673         .sysfs_ops = &efivar_attr_ops,
 674         .default_attrs = def_attrs,
 675 };
 676
 677 static inline void
 678 efivar_unregister(struct efivar_entry *var)
 679 {
 680         kobject_put(&var->kobj);
 681 }
 682
 683 static int efi_status_to_err(efi_status_t status)
 684 {
 685         int err;
 686
 687         switch (status) {
 688         case EFI_INVALID_PARAMETER:
 689                 err = -EINVAL;
 690                 break;
 691         case EFI_OUT_OF_RESOURCES:
 692                 err = -ENOSPC;
 693                 break;
 694         case EFI_DEVICE_ERROR:
 695                 err = -EIO;
 696                 break;
 697         case EFI_WRITE_PROTECTED:
 698                 err = -EROFS;
 699                 break;
 700         case EFI_SECURITY_VIOLATION:
 701                 err = -EACCES;
 702                 break;
 703         case EFI_NOT_FOUND:
 704                 err = -ENOENT;
 705                 break;
 706         default:
 707                 err = -EINVAL;
 708         }
 709
 710         return err;
 711 }
 712
 713 #ifdef CONFIG_EFI_VARS_PSTORE
 714
 715 static int efi_pstore_open(struct pstore_info *psi)
 716 {
 717         struct efivars *efivars = psi->data;
 718
 719         spin_lock_irq(&efivars->lock);
 720         efivars->walk_entry = list_first_entry(&efivars->list,
 721                                                struct efivar_entry, list);
 722         return 0;
 723 }
 724
 725 static int efi_pstore_close(struct pstore_info *psi)
 726 {
 727         struct efivars *efivars = psi->data;
 728
 729         spin_unlock_irq(&efivars->lock);
 730         return 0;
 731 }
 732
 733 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 734                                struct timespec *timespec,
 735                                char **buf, struct pstore_info *psi)
 736 {
 737         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 738         struct efivars *efivars = psi->data;
 739         char name[DUMP_NAME_LEN];
 740         int i;
 741         unsigned int part, size;
 742         unsigned long time;
 743
 744         while (&efivars->walk_entry->list != &efivars->list) {
 745                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 746                                  vendor)) {
 747                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 748                                 name[i] = efivars->walk_entry->var.VariableName[i];
 749                         }
 750                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 751                                 *id = part;
 752                                 timespec->tv_sec = time;
 753                                 timespec->tv_nsec = 0;
 754                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 755                                 size = efivars->walk_entry->var.DataSize;
 756                                 *buf = kmalloc(size, GFP_KERNEL);
 757                                 if (*buf == NULL)
 758                                         return -ENOMEM;
 759                                 memcpy(*buf, efivars->walk_entry->var.Data,
 760                                        size);
 761                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 762                                                    struct efivar_entry, list);
 763                                 return size;
 764                         }
 765                 }
 766                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 767                                                  struct efivar_entry, list);
 768         }
 769         return 0;
 770 }
 771
 772 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
 773                 unsigned int part, size_t size, struct pstore_info *psi)
 774 {
 775         char name[DUMP_NAME_LEN];
 776         char stub_name[DUMP_NAME_LEN];
 777         efi_char16_t efi_name[DUMP_NAME_LEN];
 778         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 779         struct efivars *efivars = psi->data;
 780         struct efivar_entry *entry, *found = NULL;
 781         int i, ret = 0;
 782         efi_status_t status = EFI_NOT_FOUND;
 783         unsigned long flags;
 784
 785         sprintf(stub_name, "dump-type%u-%u-", type, part);
 786         sprintf(name, "%s%lu", stub_name, get_seconds());
 787
 788         spin_lock_irqsave(&efivars->lock, flags);
 789
 790         /*
 791          * Check if there is a space enough to log.
 792          * size: a size of logging data
 793          * DUMP_NAME_LEN * 2: a maximum size of variable name
 794          */
 795
 796         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
 797                                          size + DUMP_NAME_LEN * 2);
 798
 799         if (status) {
 800                 spin_unlock_irqrestore(&efivars->lock, flags);
 801                 *id = part;
 802                 return -ENOSPC;
 803         }
 804
 805         for (i = 0; i < DUMP_NAME_LEN; i++)
 806                 efi_name[i] = stub_name[i];
 807
 808         /*
 809          * Clean up any entries with the same name
 810          */
 811
 812         list_for_each_entry(entry, &efivars->list, list) {
 813                 get_var_data_locked(efivars, &entry->var);
 814
 815                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
 816                         continue;
 817                 if (utf16_strncmp(entry->var.VariableName, efi_name,
 818                                   utf16_strlen(efi_name)))
 819                         continue;
 820                 /* Needs to be a prefix */
 821                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 822                         continue;
 823
 824                 /* found */
 825                 found = entry;
 826                 efivars->ops->set_variable(entry->var.VariableName,
 827                                            &entry->var.VendorGuid,
 828                                            PSTORE_EFI_ATTRIBUTES,
 829                                            0, NULL);
 830         }
 831
 832         if (found)
 833                 list_del(&found->list);
 834
 835         for (i = 0; i < DUMP_NAME_LEN; i++)
 836                 efi_name[i] = name[i];
 837
 838         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 839                                    size, psi->buf);
 840
 841         spin_unlock_irqrestore(&efivars->lock, flags);
 842
 843         if (found)
 844                 efivar_unregister(found);
 845
 846         if (efivar_wq_enabled)
 847                 schedule_work(&efivar_work);
 848
 849         *id = part;
 850         return ret;
 851 };
 852
 853 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 854                             struct pstore_info *psi)
 855 {
 856         efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
 857
 858         return 0;
 859 }
 860
 861 static struct pstore_info efi_pstore_info = {
 862         .owner          = THIS_MODULE,
 863         .name           = "efi",
 864         .open           = efi_pstore_open,
 865         .close          = efi_pstore_close,
 866         .read           = efi_pstore_read,
 867         .write          = efi_pstore_write,
 868         .erase          = efi_pstore_erase,
 869 };
 870
 871 static void efivar_pstore_register(struct efivars *efivars)
 872 {
 873         efivars->efi_pstore_info = efi_pstore_info;
 874         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
 875         if (efivars->efi_pstore_info.buf) {
 876                 efivars->efi_pstore_info.bufsize = 1024;
 877                 efivars->efi_pstore_info.data = efivars;
 878                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
 879                 pstore_register(&efivars->efi_pstore_info);
 880         }
 881 }
 882 #else
 883 static void efivar_pstore_register(struct efivars *efivars)
 884 {
 885         return;
 886 }
 887 #endif
 888
 889 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 890                              struct bin_attribute *bin_attr,
 891                              char *buf, loff_t pos, size_t count)
 892 {
 893         struct efi_variable *new_var = (struct efi_variable *)buf;
 894         struct efivars *efivars = bin_attr->private;
 895         struct efivar_entry *search_efivar, *n;
 896         unsigned long strsize1, strsize2;
 897         efi_status_t status = EFI_NOT_FOUND;
 898         int found = 0;
 899
 900         if (!capable(CAP_SYS_ADMIN))
 901                 return -EACCES;
 902
 903         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 904             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 905                 printk(KERN_ERR "efivars: Malformed variable content\n");
 906                 return -EINVAL;
 907         }
 908
 909         spin_lock_irq(&efivars->lock);
 910
 911         /*
 912          * Does this variable already exist?
 913          */
 914         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 915                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 916                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
 917                 if (strsize1 == strsize2 &&
 918                         !memcmp(&(search_efivar->var.VariableName),
 919                                 new_var->VariableName, strsize1) &&
 920                         !efi_guidcmp(search_efivar->var.VendorGuid,
 921                                 new_var->VendorGuid)) {
 922                         found = 1;
 923                         break;
 924                 }
 925         }
 926         if (found) {
 927                 spin_unlock_irq(&efivars->lock);
 928                 return -EINVAL;
 929         }
 930
 931         status = check_var_size_locked(efivars, new_var->Attributes,
 932                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 933
 934         if (status && status != EFI_UNSUPPORTED) {
 935                 spin_unlock_irq(&efivars->lock);
 936                 return efi_status_to_err(status);
 937         }
 938
 939         /* now *really* create the variable via EFI */
 940         status = efivars->ops->set_variable(new_var->VariableName,
 941                                             &new_var->VendorGuid,
 942                                             new_var->Attributes,
 943                                             new_var->DataSize,
 944                                             new_var->Data);
 945
 946         if (status != EFI_SUCCESS) {
 947                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 948                         status);
 949                 spin_unlock_irq(&efivars->lock);
 950                 return -EIO;
 951         }
 952         spin_unlock_irq(&efivars->lock);
 953
 954         /* Create the entry in sysfs.  Locking is not required here */
 955         status = efivar_create_sysfs_entry(efivars,
 956                                            utf16_strsize(new_var->VariableName,
 957                                                          1024),
 958                                            new_var->VariableName,
 959                                            &new_var->VendorGuid);
 960         if (status) {
 961                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 962         }
 963         return count;
 964 }
 965
 966 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 967                              struct bin_attribute *bin_attr,
 968                              char *buf, loff_t pos, size_t count)
 969 {
 970         struct efi_variable *del_var = (struct efi_variable *)buf;
 971         struct efivars *efivars = bin_attr->private;
 972         struct efivar_entry *search_efivar, *n;
 973         unsigned long strsize1, strsize2;
 974         efi_status_t status = EFI_NOT_FOUND;
 975         int found = 0;
 976
 977         if (!capable(CAP_SYS_ADMIN))
 978                 return -EACCES;
 979
 980         spin_lock_irq(&efivars->lock);
 981
 982         /*
 983          * Does this variable already exist?
 984          */
 985         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 986                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 987                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
 988                 if (strsize1 == strsize2 &&
 989                         !memcmp(&(search_efivar->var.VariableName),
 990                                 del_var->VariableName, strsize1) &&
 991                         !efi_guidcmp(search_efivar->var.VendorGuid,
 992                                 del_var->VendorGuid)) {
 993                         found = 1;
 994                         break;
 995                 }
 996         }
 997         if (!found) {
 998                 spin_unlock_irq(&efivars->lock);
 999                 return -EINVAL;
1000         }
1001         /* force the Attributes/DataSize to 0 to ensure deletion */
1002         del_var->Attributes = 0;
1003         del_var->DataSize = 0;
1004
1005         status = efivars->ops->set_variable(del_var->VariableName,
1006                                             &del_var->VendorGuid,
1007                                             del_var->Attributes,
1008                                             del_var->DataSize,
1009                                             del_var->Data);
1010
1011         if (status != EFI_SUCCESS) {
1012                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1013                         status);
1014                 spin_unlock_irq(&efivars->lock);
1015                 return -EIO;
1016         }
1017         list_del(&search_efivar->list);
1018         /* We need to release this lock before unregistering. */
1019         spin_unlock_irq(&efivars->lock);
1020         efivar_unregister(search_efivar);
1021
1022         /* It's dead Jim.... */
1023         return count;
1024 }
1025
1026 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1027 {
1028         struct efivar_entry *entry, *n;
1029         struct efivars *efivars = &__efivars;
1030         unsigned long strsize1, strsize2;
1031         bool found = false;
1032
1033         strsize1 = utf16_strsize(variable_name, 1024);
1034         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1035                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1036                 if (strsize1 == strsize2 &&
1037                         !memcmp(variable_name, &(entry->var.VariableName),
1038                                 strsize2) &&
1039                         !efi_guidcmp(entry->var.VendorGuid,
1040                                 *vendor)) {
1041                         found = true;
1042                         break;
1043                 }
1044         }
1045         return found;
1046 }
1047
1048 /*
1049  * Returns the size of variable_name, in bytes, including the
1050  * terminating NULL character, or variable_name_size if no NULL
1051  * character is found among the first variable_name_size bytes.
1052  */
1053 static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1054                                        unsigned long variable_name_size)
1055 {
1056         unsigned long len;
1057         efi_char16_t c;
1058
1059         /*
1060          * The variable name is, by definition, a NULL-terminated
1061          * string, so make absolutely sure that variable_name_size is
1062          * the value we expect it to be. If not, return the real size.
1063          */
1064         for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1065                 c = variable_name[(len / sizeof(c)) - 1];
1066                 if (!c)
1067                         break;
1068         }
1069
1070         return min(len, variable_name_size);
1071 }
1072
1073 static void efivar_update_sysfs_entries(struct work_struct *work)
1074 {
1075         struct efivars *efivars = &__efivars;
1076         efi_guid_t vendor;
1077         efi_char16_t *variable_name;
1078         unsigned long variable_name_size = 1024;
1079         efi_status_t status = EFI_NOT_FOUND;
1080         bool found;
1081
1082         /* Add new sysfs entries */
1083         while (1) {
1084                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1085                 if (!variable_name) {
1086                         pr_err("efivars: Memory allocation failed.\n");
1087                         return;
1088                 }
1089
1090                 spin_lock_irq(&efivars->lock);
1091                 found = false;
1092                 while (1) {
1093                         variable_name_size = 1024;
1094                         status = efivars->ops->get_next_variable(
1095                                                         &variable_name_size,
1096                                                         variable_name,
1097                                                         &vendor);
1098                         if (status != EFI_SUCCESS) {
1099                                 break;
1100                         } else {
1101                                 if (!variable_is_present(variable_name,
1102                                     &vendor)) {
1103                                         found = true;
1104                                         break;
1105                                 }
1106                         }
1107                 }
1108                 spin_unlock_irq(&efivars->lock);
1109
1110                 if (!found) {
1111                         kfree(variable_name);
1112                         break;
1113                 } else {
1114                         variable_name_size = var_name_strnsize(variable_name,
1115                                                                variable_name_size);
1116                         efivar_create_sysfs_entry(efivars,
1117                                                   variable_name_size,
1118                                                   variable_name, &vendor);
1119                 }
1120         }
1121 }
1122
1123 /*
1124  * Let's not leave out systab information that snuck into
1125  * the efivars driver
1126  */
1127 static ssize_t systab_show(struct kobject *kobj,
1128                            struct kobj_attribute *attr, char *buf)
1129 {
1130         char *str = buf;
1131
1132         if (!kobj || !buf)
1133                 return -EINVAL;
1134
1135         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1136                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1137         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1138                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1139         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1140                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1141         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1142                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1143         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1144                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1145         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1146                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1147         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1148                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1149
1150         return str - buf;
1151 }
1152
1153 static struct kobj_attribute efi_attr_systab =
1154                         __ATTR(systab, 0400, systab_show, NULL);
1155
1156 static struct attribute *efi_subsys_attrs[] = {
1157         &efi_attr_systab.attr,
1158         NULL,   /* maybe more in the future? */
1159 };
1160
1161 static struct attribute_group efi_subsys_attr_group = {
1162         .attrs = efi_subsys_attrs,
1163 };
1164
1165 static struct kobject *efi_kobj;
1166
1167 /*
1168  * efivar_create_sysfs_entry()
1169  * Requires:
1170  *    variable_name_size = number of bytes required to hold
1171  *                         variable_name (not counting the NULL
1172  *                         character at the end.
1173  *    efivars->lock is not held on entry or exit.
1174  * Returns 1 on failure, 0 on success
1175  */
1176 static int
1177 efivar_create_sysfs_entry(struct efivars *efivars,
1178                           unsigned long variable_name_size,
1179                           efi_char16_t *variable_name,
1180                           efi_guid_t *vendor_guid)
1181 {
1182         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1183         char *short_name;
1184         struct efivar_entry *new_efivar;
1185
1186         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1187         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1188
1189         if (!short_name || !new_efivar)  {
1190                 kfree(short_name);
1191                 kfree(new_efivar);
1192                 return 1;
1193         }
1194
1195         new_efivar->efivars = efivars;
1196         memcpy(new_efivar->var.VariableName, variable_name,
1197                 variable_name_size);
1198         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1199
1200         /* Convert Unicode to normal chars (assume top bits are 0),
1201            ala UTF-8 */
1202         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1203                 short_name[i] = variable_name[i] & 0xFF;
1204         }
1205         /* This is ugly, but necessary to separate one vendor's
1206            private variables from another's.         */
1207
1208         *(short_name + strlen(short_name)) = '-';
1209         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1210
1211         new_efivar->kobj.kset = efivars->kset;
1212         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1213                                  "%s", short_name);
1214         if (i) {
1215                 kfree(short_name);
1216                 kfree(new_efivar);
1217                 return 1;
1218         }
1219
1220         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1221         kfree(short_name);
1222         short_name = NULL;
1223
1224         spin_lock_irq(&efivars->lock);
1225         list_add(&new_efivar->list, &efivars->list);
1226         spin_unlock_irq(&efivars->lock);
1227
1228         return 0;
1229 }
1230
1231 static int
1232 create_efivars_bin_attributes(struct efivars *efivars)
1233 {
1234         struct bin_attribute *attr;
1235         int error;
1236
1237         /* new_var */
1238         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1239         if (!attr)
1240                 return -ENOMEM;
1241
1242         attr->attr.name = "new_var";
1243         attr->attr.mode = 0200;
1244         attr->write = efivar_create;
1245         attr->private = efivars;
1246         efivars->new_var = attr;
1247
1248         /* del_var */
1249         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1250         if (!attr) {
1251                 error = -ENOMEM;
1252                 goto out_free;
1253         }
1254         attr->attr.name = "del_var";
1255         attr->attr.mode = 0200;
1256         attr->write = efivar_delete;
1257         attr->private = efivars;
1258         efivars->del_var = attr;
1259
1260         sysfs_bin_attr_init(efivars->new_var);
1261         sysfs_bin_attr_init(efivars->del_var);
1262
1263         /* Register */
1264         error = sysfs_create_bin_file(&efivars->kset->kobj,
1265                                       efivars->new_var);
1266         if (error) {
1267                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1268                         " due to error %d\n", error);
1269                 goto out_free;
1270         }
1271         error = sysfs_create_bin_file(&efivars->kset->kobj,
1272                                       efivars->del_var);
1273         if (error) {
1274                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1275                         " due to error %d\n", error);
1276                 sysfs_remove_bin_file(&efivars->kset->kobj,
1277                                       efivars->new_var);
1278                 goto out_free;
1279         }
1280
1281         return 0;
1282 out_free:
1283         kfree(efivars->del_var);
1284         efivars->del_var = NULL;
1285         kfree(efivars->new_var);
1286         efivars->new_var = NULL;
1287         return error;
1288 }
1289
1290 void unregister_efivars(struct efivars *efivars)
1291 {
1292         struct efivar_entry *entry, *n;
1293
1294         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1295                 spin_lock_irq(&efivars->lock);
1296                 list_del(&entry->list);
1297                 spin_unlock_irq(&efivars->lock);
1298                 efivar_unregister(entry);
1299         }
1300         if (efivars->new_var)
1301                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1302         if (efivars->del_var)
1303                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1304         kfree(efivars->new_var);
1305         kfree(efivars->del_var);
1306         kset_unregister(efivars->kset);
1307 }
1308 EXPORT_SYMBOL_GPL(unregister_efivars);
1309
1310 /*
1311  * Print a warning when duplicate EFI variables are encountered and
1312  * disable the sysfs workqueue since the firmware is buggy.
1313  */
1314 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1315                              unsigned long len16)
1316 {
1317         size_t i, len8 = len16 / sizeof(efi_char16_t);
1318         char *s8;
1319
1320         /*
1321          * Disable the workqueue since the algorithm it uses for
1322          * detecting new variables won't work with this buggy
1323          * implementation of GetNextVariableName().
1324          */
1325         efivar_wq_enabled = false;
1326
1327         s8 = kzalloc(len8, GFP_KERNEL);
1328         if (!s8)
1329                 return;
1330
1331         for (i = 0; i < len8; i++)
1332                 s8[i] = s16[i];
1333
1334         printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
1335                s8, vendor_guid);
1336         kfree(s8);
1337 }
1338
1339 int register_efivars(struct efivars *efivars,
1340                      const struct efivar_operations *ops,
1341                      struct kobject *parent_kobj)
1342 {
1343         efi_status_t status = EFI_NOT_FOUND;
1344         efi_guid_t vendor_guid;
1345         efi_char16_t *variable_name;
1346         unsigned long variable_name_size = 1024;
1347         int error = 0;
1348
1349         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1350         if (!variable_name) {
1351                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1352                 return -ENOMEM;
1353         }
1354
1355         spin_lock_init(&efivars->lock);
1356         INIT_LIST_HEAD(&efivars->list);
1357         efivars->ops = ops;
1358
1359         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1360         if (!efivars->kset) {
1361                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1362                 error = -ENOMEM;
1363                 goto out;
1364         }
1365
1366         /*
1367          * Per EFI spec, the maximum storage allocated for both
1368          * the variable name and variable data is 1024 bytes.
1369          */
1370
1371         do {
1372                 variable_name_size = 1024;
1373
1374                 status = ops->get_next_variable(&variable_name_size,
1375                                                 variable_name,
1376                                                 &vendor_guid);
1377                 switch (status) {
1378                 case EFI_SUCCESS:
1379                         variable_name_size = var_name_strnsize(variable_name,
1380                                                                variable_name_size);
1381
1382                         /*
1383                          * Some firmware implementations return the
1384                          * same variable name on multiple calls to
1385                          * get_next_variable(). Terminate the loop
1386                          * immediately as there is no guarantee that
1387                          * we'll ever see a different variable name,
1388                          * and may end up looping here forever.
1389                          */
1390                         if (variable_is_present(variable_name, &vendor_guid)) {
1391                                 dup_variable_bug(variable_name, &vendor_guid,
1392                                                  variable_name_size);
1393                                 status = EFI_NOT_FOUND;
1394                                 break;
1395                         }
1396
1397                         efivar_create_sysfs_entry(efivars,
1398                                                   variable_name_size,
1399                                                   variable_name,
1400                                                   &vendor_guid);
1401                         break;
1402                 case EFI_NOT_FOUND:
1403                         break;
1404                 default:
1405                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1406                                 status);
1407                         status = EFI_NOT_FOUND;
1408                         break;
1409                 }
1410         } while (status != EFI_NOT_FOUND);
1411
1412         error = create_efivars_bin_attributes(efivars);
1413         if (error)
1414                 unregister_efivars(efivars);
1415
1416         if (!efivars_pstore_disable)
1417                 efivar_pstore_register(efivars);
1418
1419 out:
1420         kfree(variable_name);
1421
1422         return error;
1423 }
1424 EXPORT_SYMBOL_GPL(register_efivars);
1425
1426 static struct efivar_operations ops;
1427
1428 /*
1429  * For now we register the efi subsystem with the firmware subsystem
1430  * and the vars subsystem with the efi subsystem.  In the future, it
1431  * might make sense to split off the efi subsystem into its own
1432  * driver, but for now only efivars will register with it, so just
1433  * include it here.
1434  */
1435
1436 static int __init
1437 efivars_init(void)
1438 {
1439         int error = 0;
1440
1441         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1442                EFIVARS_DATE);
1443
1444         if (!efi_enabled(EFI_RUNTIME_SERVICES))
1445                 return 0;
1446
1447         /* For now we'll register the efi directory at /sys/firmware/efi */
1448         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1449         if (!efi_kobj) {
1450                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1451                 return -ENOMEM;
1452         }
1453
1454         ops.get_variable = efi.get_variable;
1455         ops.set_variable = efi.set_variable;
1456         ops.get_next_variable = efi.get_next_variable;
1457         ops.query_variable_info = efi.query_variable_info;
1458         error = register_efivars(&__efivars, &ops, efi_kobj);
1459         if (error)
1460                 goto err_put;
1461
1462         /* Don't forget the systab entry */
1463         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1464         if (error) {
1465                 printk(KERN_ERR
1466                        "efivars: Sysfs attribute export failed with error %d.\n",
1467                        error);
1468                 goto err_unregister;
1469         }
1470
1471         return 0;
1472
1473 err_unregister:
1474         unregister_efivars(&__efivars);
1475 err_put:
1476         kobject_put(efi_kobj);
1477         return error;
1478 }
1479
1480 static void __exit
1481 efivars_exit(void)
1482 {
1483         cancel_work_sync(&efivar_work);
1484
1485         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1486                 unregister_efivars(&__efivars);
1487                 kobject_put(efi_kobj);
1488         }
1489 }
1490
1491 module_init(efivars_init);
1492 module_exit(efivars_exit);
1493