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 #include <linux/ctype.h>
  83
  84 #include <linux/fs.h>
  85 #include <linux/ramfs.h>
  86 #include <linux/pagemap.h>
  87
  88 #include <asm/uaccess.h>
  89
  90 #define EFIVARS_VERSION "0.08"
  91 #define EFIVARS_DATE "2004-May-17"
  92
  93 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  94 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  95 MODULE_LICENSE("GPL");
  96 MODULE_VERSION(EFIVARS_VERSION);
  97
  98 #define DUMP_NAME_LEN 52
  99
 100 /*
 101  * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
 102  * not including trailing NUL
 103  */
 104 #define GUID_LEN 36
 105
 106 static bool efivars_pstore_disable =
 107         IS_ENABLED(EFI_VARS_PSTORE_DEFAULT_DISABLE);
 108
 109 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
 110
 111 /*
 112  * The maximum size of VariableName + Data = 1024
 113  * Therefore, it's reasonable to save that much
 114  * space in each part of the structure,
 115  * and we use a page for reading/writing.
 116  */
 117
 118 struct efi_variable {
 119         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 120         efi_guid_t    VendorGuid;
 121         unsigned long DataSize;
 122         __u8          Data[1024];
 123         efi_status_t  Status;
 124         __u32         Attributes;
 125 } __attribute__((packed));
 126
 127 struct efivar_entry {
 128         struct efivars *efivars;
 129         struct efi_variable var;
 130         struct list_head list;
 131         struct kobject kobj;
 132 };
 133
 134 struct efivar_attribute {
 135         struct attribute attr;
 136         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 137         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 138 };
 139
 140 static struct efivars __efivars;
 141 static struct efivar_operations ops;
 142
 143 #define PSTORE_EFI_ATTRIBUTES \
 144         (EFI_VARIABLE_NON_VOLATILE | \
 145          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 146          EFI_VARIABLE_RUNTIME_ACCESS)
 147
 148 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 149 struct efivar_attribute efivar_attr_##_name = { \
 150         .attr = {.name = __stringify(_name), .mode = _mode}, \
 151         .show = _show, \
 152         .store = _store, \
 153 };
 154
 155 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 156 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 157
 158 /*
 159  * Prototype for sysfs creation function
 160  */
 161 static int
 162 efivar_create_sysfs_entry(struct efivars *efivars,
 163                           unsigned long variable_name_size,
 164                           efi_char16_t *variable_name,
 165                           efi_guid_t *vendor_guid);
 166
 167 /*
 168  * Prototype for workqueue functions updating sysfs entry
 169  */
 170
 171 static void efivar_update_sysfs_entries(struct work_struct *);
 172 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
 173
 174 /* Return the number of unicode characters in data */
 175 static unsigned long
 176 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 177 {
 178         unsigned long length = 0;
 179
 180         while (*s++ != 0 && length < maxlength)
 181                 length++;
 182         return length;
 183 }
 184
 185 static inline unsigned long
 186 utf16_strlen(efi_char16_t *s)
 187 {
 188         return utf16_strnlen(s, ~0UL);
 189 }
 190
 191 /*
 192  * Return the number of bytes is the length of this string
 193  * Note: this is NOT the same as the number of unicode characters
 194  */
 195 static inline unsigned long
 196 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 197 {
 198         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 199 }
 200
 201 static inline int
 202 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 203 {
 204         while (1) {
 205                 if (len == 0)
 206                         return 0;
 207                 if (*a < *b)
 208                         return -1;
 209                 if (*a > *b)
 210                         return 1;
 211                 if (*a == 0) /* implies *b == 0 */
 212                         return 0;
 213                 a++;
 214                 b++;
 215                 len--;
 216         }
 217 }
 218
 219 static bool
 220 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 221                      unsigned long len)
 222 {
 223         struct efi_generic_dev_path *node;
 224         int offset = 0;
 225
 226         node = (struct efi_generic_dev_path *)buffer;
 227
 228         if (len < sizeof(*node))
 229                 return false;
 230
 231         while (offset <= len - sizeof(*node) &&
 232                node->length >= sizeof(*node) &&
 233                 node->length <= len - offset) {
 234                 offset += node->length;
 235
 236                 if ((node->type == EFI_DEV_END_PATH ||
 237                      node->type == EFI_DEV_END_PATH2) &&
 238                     node->sub_type == EFI_DEV_END_ENTIRE)
 239                         return true;
 240
 241                 node = (struct efi_generic_dev_path *)(buffer + offset);
 242         }
 243
 244         /*
 245          * If we're here then either node->length pointed past the end
 246          * of the buffer or we reached the end of the buffer without
 247          * finding a device path end node.
 248          */
 249         return false;
 250 }
 251
 252 static bool
 253 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 254                     unsigned long len)
 255 {
 256         /* An array of 16-bit integers */
 257         if ((len % 2) != 0)
 258                 return false;
 259
 260         return true;
 261 }
 262
 263 static bool
 264 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 265                      unsigned long len)
 266 {
 267         u16 filepathlength;
 268         int i, desclength = 0, namelen;
 269
 270         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 271
 272         /* Either "Boot" or "Driver" followed by four digits of hex */
 273         for (i = match; i < match+4; i++) {
 274                 if (var->VariableName[i] > 127 ||
 275                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 276                         return true;
 277         }
 278
 279         /* Reject it if there's 4 digits of hex and then further content */
 280         if (namelen > match + 4)
 281                 return false;
 282
 283         /* A valid entry must be at least 8 bytes */
 284         if (len < 8)
 285                 return false;
 286
 287         filepathlength = buffer[4] | buffer[5] << 8;
 288
 289         /*
 290          * There's no stored length for the description, so it has to be
 291          * found by hand
 292          */
 293         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 294
 295         /* Each boot entry must have a descriptor */
 296         if (!desclength)
 297                 return false;
 298
 299         /*
 300          * If the sum of the length of the description, the claimed filepath
 301          * length and the original header are greater than the length of the
 302          * variable, it's malformed
 303          */
 304         if ((desclength + filepathlength + 6) > len)
 305                 return false;
 306
 307         /*
 308          * And, finally, check the filepath
 309          */
 310         return validate_device_path(var, match, buffer + desclength + 6,
 311                                     filepathlength);
 312 }
 313
 314 static bool
 315 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 316                 unsigned long len)
 317 {
 318         /* A single 16-bit integer */
 319         if (len != 2)
 320                 return false;
 321
 322         return true;
 323 }
 324
 325 static bool
 326 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 327                       unsigned long len)
 328 {
 329         int i;
 330
 331         for (i = 0; i < len; i++) {
 332                 if (buffer[i] > 127)
 333                         return false;
 334
 335                 if (buffer[i] == 0)
 336                         return true;
 337         }
 338
 339         return false;
 340 }
 341
 342 struct variable_validate {
 343         char *name;
 344         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 345                          unsigned long len);
 346 };
 347
 348 static const struct variable_validate variable_validate[] = {
 349         { "BootNext", validate_uint16 },
 350         { "BootOrder", validate_boot_order },
 351         { "DriverOrder", validate_boot_order },
 352         { "Boot*", validate_load_option },
 353         { "Driver*", validate_load_option },
 354         { "ConIn", validate_device_path },
 355         { "ConInDev", validate_device_path },
 356         { "ConOut", validate_device_path },
 357         { "ConOutDev", validate_device_path },
 358         { "ErrOut", validate_device_path },
 359         { "ErrOutDev", validate_device_path },
 360         { "Timeout", validate_uint16 },
 361         { "Lang", validate_ascii_string },
 362         { "PlatformLang", validate_ascii_string },
 363         { "", NULL },
 364 };
 365
 366 static bool
 367 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 368 {
 369         int i;
 370         u16 *unicode_name = var->VariableName;
 371
 372         for (i = 0; variable_validate[i].validate != NULL; i++) {
 373                 const char *name = variable_validate[i].name;
 374                 int match;
 375
 376                 for (match = 0; ; match++) {
 377                         char c = name[match];
 378                         u16 u = unicode_name[match];
 379
 380                         /* All special variables are plain ascii */
 381                         if (u > 127)
 382                                 return true;
 383
 384                         /* Wildcard in the matching name means we've matched */
 385                         if (c == '*')
 386                                 return variable_validate[i].validate(var,
 387                                                              match, data, len);
 388
 389                         /* Case sensitive match */
 390                         if (c != u)
 391                                 break;
 392
 393                         /* Reached the end of the string while matching */
 394                         if (!c)
 395                                 return variable_validate[i].validate(var,
 396                                                              match, data, len);
 397                 }
 398         }
 399
 400         return true;
 401 }
 402
 403 static efi_status_t
 404 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 405 {
 406         efi_status_t status;
 407
 408         var->DataSize = 1024;
 409         status = efivars->ops->get_variable(var->VariableName,
 410                                             &var->VendorGuid,
 411                                             &var->Attributes,
 412                                             &var->DataSize,
 413                                             var->Data);
 414         return status;
 415 }
 416
 417 static efi_status_t
 418 get_var_data(struct efivars *efivars, struct efi_variable *var)
 419 {
 420         efi_status_t status;
 421         unsigned long flags;
 422
 423         spin_lock_irqsave(&efivars->lock, flags);
 424         status = get_var_data_locked(efivars, var);
 425         spin_unlock_irqrestore(&efivars->lock, flags);
 426
 427         if (status != EFI_SUCCESS) {
 428                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 429                         status);
 430         }
 431         return status;
 432 }
 433
 434 static efi_status_t
 435 check_var_size_locked(struct efivars *efivars, u32 attributes,
 436                         unsigned long size)
 437 {
 438         u64 storage_size, remaining_size, max_size;
 439         efi_status_t status;
 440         const struct efivar_operations *fops = efivars->ops;
 441
 442         if (!efivars->ops->query_variable_info)
 443                 return EFI_UNSUPPORTED;
 444
 445         status = fops->query_variable_info(attributes, &storage_size,
 446                                            &remaining_size, &max_size);
 447
 448         if (status != EFI_SUCCESS)
 449                 return status;
 450
 451         if (!storage_size || size > remaining_size || size > max_size ||
 452             (remaining_size - size) < (storage_size / 2))
 453                 return EFI_OUT_OF_RESOURCES;
 454
 455         return status;
 456 }
 457
 458
 459 static efi_status_t
 460 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
 461 {
 462         efi_status_t status;
 463         unsigned long flags;
 464
 465         spin_lock_irqsave(&efivars->lock, flags);
 466         status = check_var_size_locked(efivars, attributes, size);
 467         spin_unlock_irqrestore(&efivars->lock, flags);
 468
 469         return status;
 470 }
 471
 472 static ssize_t
 473 efivar_guid_read(struct efivar_entry *entry, char *buf)
 474 {
 475         struct efi_variable *var = &entry->var;
 476         char *str = buf;
 477
 478         if (!entry || !buf)
 479                 return 0;
 480
 481         efi_guid_unparse(&var->VendorGuid, str);
 482         str += strlen(str);
 483         str += sprintf(str, "\n");
 484
 485         return str - buf;
 486 }
 487
 488 static ssize_t
 489 efivar_attr_read(struct efivar_entry *entry, char *buf)
 490 {
 491         struct efi_variable *var = &entry->var;
 492         char *str = buf;
 493         efi_status_t status;
 494
 495         if (!entry || !buf)
 496                 return -EINVAL;
 497
 498         status = get_var_data(entry->efivars, var);
 499         if (status != EFI_SUCCESS)
 500                 return -EIO;
 501
 502         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 503                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 504         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 505                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 506         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 507                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 508         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 509                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 510         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 511                 str += sprintf(str,
 512                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 513         if (var->Attributes &
 514                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 515                 str += sprintf(str,
 516                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 517         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 518                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 519         return str - buf;
 520 }
 521
 522 static ssize_t
 523 efivar_size_read(struct efivar_entry *entry, char *buf)
 524 {
 525         struct efi_variable *var = &entry->var;
 526         char *str = buf;
 527         efi_status_t status;
 528
 529         if (!entry || !buf)
 530                 return -EINVAL;
 531
 532         status = get_var_data(entry->efivars, var);
 533         if (status != EFI_SUCCESS)
 534                 return -EIO;
 535
 536         str += sprintf(str, "0x%lx\n", var->DataSize);
 537         return str - buf;
 538 }
 539
 540 static ssize_t
 541 efivar_data_read(struct efivar_entry *entry, char *buf)
 542 {
 543         struct efi_variable *var = &entry->var;
 544         efi_status_t status;
 545
 546         if (!entry || !buf)
 547                 return -EINVAL;
 548
 549         status = get_var_data(entry->efivars, var);
 550         if (status != EFI_SUCCESS)
 551                 return -EIO;
 552
 553         memcpy(buf, var->Data, var->DataSize);
 554         return var->DataSize;
 555 }
 556 /*
 557  * We allow each variable to be edited via rewriting the
 558  * entire efi variable structure.
 559  */
 560 static ssize_t
 561 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 562 {
 563         struct efi_variable *new_var, *var = &entry->var;
 564         struct efivars *efivars = entry->efivars;
 565         efi_status_t status = EFI_NOT_FOUND;
 566
 567         if (count != sizeof(struct efi_variable))
 568                 return -EINVAL;
 569
 570         new_var = (struct efi_variable *)buf;
 571         /*
 572          * If only updating the variable data, then the name
 573          * and guid should remain the same
 574          */
 575         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 576                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 577                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 578                 return -EINVAL;
 579         }
 580
 581         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 582                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 583                 return -EINVAL;
 584         }
 585
 586         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 587             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 588                 printk(KERN_ERR "efivars: Malformed variable content\n");
 589                 return -EINVAL;
 590         }
 591
 592         spin_lock_irq(&efivars->lock);
 593
 594         status = check_var_size_locked(efivars, new_var->Attributes,
 595                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 596
 597         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 598                 status = efivars->ops->set_variable(new_var->VariableName,
 599                                                     &new_var->VendorGuid,
 600                                                     new_var->Attributes,
 601                                                     new_var->DataSize,
 602                                                     new_var->Data);
 603
 604         spin_unlock_irq(&efivars->lock);
 605
 606         if (status != EFI_SUCCESS) {
 607                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 608                         status);
 609                 return -EIO;
 610         }
 611
 612         memcpy(&entry->var, new_var, count);
 613         return count;
 614 }
 615
 616 static ssize_t
 617 efivar_show_raw(struct efivar_entry *entry, char *buf)
 618 {
 619         struct efi_variable *var = &entry->var;
 620         efi_status_t status;
 621
 622         if (!entry || !buf)
 623                 return 0;
 624
 625         status = get_var_data(entry->efivars, var);
 626         if (status != EFI_SUCCESS)
 627                 return -EIO;
 628
 629         memcpy(buf, var, sizeof(*var));
 630         return sizeof(*var);
 631 }
 632
 633 /*
 634  * Generic read/write functions that call the specific functions of
 635  * the attributes...
 636  */
 637 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 638                                 char *buf)
 639 {
 640         struct efivar_entry *var = to_efivar_entry(kobj);
 641         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 642         ssize_t ret = -EIO;
 643
 644         if (!capable(CAP_SYS_ADMIN))
 645                 return -EACCES;
 646
 647         if (efivar_attr->show) {
 648                 ret = efivar_attr->show(var, buf);
 649         }
 650         return ret;
 651 }
 652
 653 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 654                                 const char *buf, size_t count)
 655 {
 656         struct efivar_entry *var = to_efivar_entry(kobj);
 657         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 658         ssize_t ret = -EIO;
 659
 660         if (!capable(CAP_SYS_ADMIN))
 661                 return -EACCES;
 662
 663         if (efivar_attr->store)
 664                 ret = efivar_attr->store(var, buf, count);
 665
 666         return ret;
 667 }
 668
 669 static const struct sysfs_ops efivar_attr_ops = {
 670         .show = efivar_attr_show,
 671         .store = efivar_attr_store,
 672 };
 673
 674 static void efivar_release(struct kobject *kobj)
 675 {
 676         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 677         kfree(var);
 678 }
 679
 680 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 681 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 682 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 683 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 684 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 685
 686 static struct attribute *def_attrs[] = {
 687         &efivar_attr_guid.attr,
 688         &efivar_attr_size.attr,
 689         &efivar_attr_attributes.attr,
 690         &efivar_attr_data.attr,
 691         &efivar_attr_raw_var.attr,
 692         NULL,
 693 };
 694
 695 static struct kobj_type efivar_ktype = {
 696         .release = efivar_release,
 697         .sysfs_ops = &efivar_attr_ops,
 698         .default_attrs = def_attrs,
 699 };
 700
 701 static inline void
 702 efivar_unregister(struct efivar_entry *var)
 703 {
 704         kobject_put(&var->kobj);
 705 }
 706
 707 static int efivarfs_file_open(struct inode *inode, struct file *file)
 708 {
 709         file->private_data = inode->i_private;
 710         return 0;
 711 }
 712
 713 static int efi_status_to_err(efi_status_t status)
 714 {
 715         int err;
 716
 717         switch (status) {
 718         case EFI_INVALID_PARAMETER:
 719                 err = -EINVAL;
 720                 break;
 721         case EFI_OUT_OF_RESOURCES:
 722                 err = -ENOSPC;
 723                 break;
 724         case EFI_DEVICE_ERROR:
 725                 err = -EIO;
 726                 break;
 727         case EFI_WRITE_PROTECTED:
 728                 err = -EROFS;
 729                 break;
 730         case EFI_SECURITY_VIOLATION:
 731                 err = -EACCES;
 732                 break;
 733         case EFI_NOT_FOUND:
 734                 err = -EIO;
 735                 break;
 736         default:
 737                 err = -EINVAL;
 738         }
 739
 740         return err;
 741 }
 742
 743 static ssize_t efivarfs_file_write(struct file *file,
 744                 const char __user *userbuf, size_t count, loff_t *ppos)
 745 {
 746         struct efivar_entry *var = file->private_data;
 747         struct efivars *efivars;
 748         efi_status_t status;
 749         void *data;
 750         u32 attributes;
 751         struct inode *inode = file->f_mapping->host;
 752         unsigned long datasize = count - sizeof(attributes);
 753         unsigned long newdatasize, varsize;
 754         ssize_t bytes = 0;
 755
 756         if (count < sizeof(attributes))
 757                 return -EINVAL;
 758
 759         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 760                 return -EFAULT;
 761
 762         if (attributes & ~(EFI_VARIABLE_MASK))
 763                 return -EINVAL;
 764
 765         efivars = var->efivars;
 766
 767         /*
 768          * Ensure that the user can't allocate arbitrarily large
 769          * amounts of memory. Pick a default size of 64K if
 770          * QueryVariableInfo() isn't supported by the firmware.
 771          */
 772
 773         varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
 774         status = check_var_size(efivars, attributes, varsize);
 775
 776         if (status != EFI_SUCCESS) {
 777                 if (status != EFI_UNSUPPORTED)
 778                         return efi_status_to_err(status);
 779
 780                 if (datasize > 65536)
 781                         return -ENOSPC;
 782         }
 783
 784         data = kmalloc(datasize, GFP_KERNEL);
 785         if (!data)
 786                 return -ENOMEM;
 787
 788         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 789                 bytes = -EFAULT;
 790                 goto out;
 791         }
 792
 793         if (validate_var(&var->var, data, datasize) == false) {
 794                 bytes = -EINVAL;
 795                 goto out;
 796         }
 797
 798         /*
 799          * The lock here protects the get_variable call, the conditional
 800          * set_variable call, and removal of the variable from the efivars
 801          * list (in the case of an authenticated delete).
 802          */
 803         spin_lock_irq(&efivars->lock);
 804
 805         /*
 806          * Ensure that the available space hasn't shrunk below the safe level
 807          */
 808
 809         status = check_var_size_locked(efivars, attributes, varsize);
 810
 811         if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
 812                 spin_unlock_irq(&efivars->lock);
 813                 kfree(data);
 814
 815                 return efi_status_to_err(status);
 816         }
 817
 818         status = efivars->ops->set_variable(var->var.VariableName,
 819                                             &var->var.VendorGuid,
 820                                             attributes, datasize,
 821                                             data);
 822
 823         if (status != EFI_SUCCESS) {
 824                 spin_unlock_irq(&efivars->lock);
 825                 kfree(data);
 826
 827                 return efi_status_to_err(status);
 828         }
 829
 830         bytes = count;
 831
 832         /*
 833          * Writing to the variable may have caused a change in size (which
 834          * could either be an append or an overwrite), or the variable to be
 835          * deleted. Perform a GetVariable() so we can tell what actually
 836          * happened.
 837          */
 838         newdatasize = 0;
 839         status = efivars->ops->get_variable(var->var.VariableName,
 840                                             &var->var.VendorGuid,
 841                                             NULL, &newdatasize,
 842                                             NULL);
 843
 844         if (status == EFI_BUFFER_TOO_SMALL) {
 845                 spin_unlock_irq(&efivars->lock);
 846                 mutex_lock(&inode->i_mutex);
 847                 i_size_write(inode, newdatasize + sizeof(attributes));
 848                 mutex_unlock(&inode->i_mutex);
 849
 850         } else if (status == EFI_NOT_FOUND) {
 851                 list_del(&var->list);
 852                 spin_unlock_irq(&efivars->lock);
 853                 efivar_unregister(var);
 854                 drop_nlink(inode);
 855                 d_delete(file->f_dentry);
 856                 dput(file->f_dentry);
 857
 858         } else {
 859                 spin_unlock_irq(&efivars->lock);
 860                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
 861                                 "status = %lx\n", status);
 862         }
 863
 864 out:
 865         kfree(data);
 866
 867         return bytes;
 868 }
 869
 870 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 871                 size_t count, loff_t *ppos)
 872 {
 873         struct efivar_entry *var = file->private_data;
 874         struct efivars *efivars = var->efivars;
 875         efi_status_t status;
 876         unsigned long datasize = 0;
 877         u32 attributes;
 878         void *data;
 879         ssize_t size = 0;
 880
 881         spin_lock_irq(&efivars->lock);
 882         status = efivars->ops->get_variable(var->var.VariableName,
 883                                             &var->var.VendorGuid,
 884                                             &attributes, &datasize, NULL);
 885         spin_unlock_irq(&efivars->lock);
 886
 887         if (status != EFI_BUFFER_TOO_SMALL)
 888                 return efi_status_to_err(status);
 889
 890         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 891
 892         if (!data)
 893                 return -ENOMEM;
 894
 895         spin_lock_irq(&efivars->lock);
 896         status = efivars->ops->get_variable(var->var.VariableName,
 897                                             &var->var.VendorGuid,
 898                                             &attributes, &datasize,
 899                                             (data + sizeof(attributes)));
 900         spin_unlock_irq(&efivars->lock);
 901
 902         if (status != EFI_SUCCESS) {
 903                 size = efi_status_to_err(status);
 904                 goto out_free;
 905         }
 906
 907         memcpy(data, &attributes, sizeof(attributes));
 908         size = simple_read_from_buffer(userbuf, count, ppos,
 909                                        data, datasize + sizeof(attributes));
 910 out_free:
 911         kfree(data);
 912
 913         return size;
 914 }
 915
 916 static void efivarfs_evict_inode(struct inode *inode)
 917 {
 918         clear_inode(inode);
 919 }
 920
 921 static const struct super_operations efivarfs_ops = {
 922         .statfs = simple_statfs,
 923         .drop_inode = generic_delete_inode,
 924         .evict_inode = efivarfs_evict_inode,
 925         .show_options = generic_show_options,
 926 };
 927
 928 static struct super_block *efivarfs_sb;
 929
 930 static const struct inode_operations efivarfs_dir_inode_operations;
 931
 932 static const struct file_operations efivarfs_file_operations = {
 933         .open   = efivarfs_file_open,
 934         .read   = efivarfs_file_read,
 935         .write  = efivarfs_file_write,
 936         .llseek = no_llseek,
 937 };
 938
 939 static struct inode *efivarfs_get_inode(struct super_block *sb,
 940                                 const struct inode *dir, int mode, dev_t dev)
 941 {
 942         struct inode *inode = new_inode(sb);
 943
 944         if (inode) {
 945                 inode->i_ino = get_next_ino();
 946                 inode->i_mode = mode;
 947                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 948                 switch (mode & S_IFMT) {
 949                 case S_IFREG:
 950                         inode->i_fop = &efivarfs_file_operations;
 951                         break;
 952                 case S_IFDIR:
 953                         inode->i_op = &efivarfs_dir_inode_operations;
 954                         inode->i_fop = &simple_dir_operations;
 955                         inc_nlink(inode);
 956                         break;
 957                 }
 958         }
 959         return inode;
 960 }
 961
 962 /*
 963  * Return true if 'str' is a valid efivarfs filename of the form,
 964  *
 965  *      VariableName-12345678-1234-1234-1234-1234567891bc
 966  */
 967 static bool efivarfs_valid_name(const char *str, int len)
 968 {
 969         static const char dashes[GUID_LEN] = {
 970                 [8] = 1, [13] = 1, [18] = 1, [23] = 1
 971         };
 972         const char *s = str + len - GUID_LEN;
 973         int i;
 974
 975         /*
 976          * We need a GUID, plus at least one letter for the variable name,
 977          * plus the '-' separator
 978          */
 979         if (len < GUID_LEN + 2)
 980                 return false;
 981
 982         /* GUID must be preceded by a '-' */
 983         if (*(s - 1) != '-')
 984                 return false;
 985
 986         /*
 987          * Validate that 's' is of the correct format, e.g.
 988          *
 989          *      12345678-1234-1234-1234-123456789abc
 990          */
 991         for (i = 0; i < GUID_LEN; i++) {
 992                 if (dashes[i]) {
 993                         if (*s++ != '-')
 994                                 return false;
 995                 } else {
 996                         if (!isxdigit(*s++))
 997                                 return false;
 998                 }
 999         }
1000
1001         return true;
1002 }
1003
1004 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
1005 {
1006         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
1007         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
1008         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
1009         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
1010         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
1011         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
1012         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
1013         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
1014         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
1015         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1016         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1017         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1018         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1019         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1020         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1021         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1022 }
1023
1024 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1025                           umode_t mode, bool excl)
1026 {
1027         struct inode *inode;
1028         struct efivars *efivars = &__efivars;
1029         struct efivar_entry *var;
1030         int namelen, i = 0, err = 0;
1031
1032         if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1033                 return -EINVAL;
1034
1035         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1036         if (!inode)
1037                 return -ENOMEM;
1038
1039         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1040         if (!var) {
1041                 err = -ENOMEM;
1042                 goto out;
1043         }
1044
1045         /* length of the variable name itself: remove GUID and separator */
1046         namelen = dentry->d_name.len - GUID_LEN - 1;
1047
1048         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1049                         &var->var.VendorGuid);
1050
1051         for (i = 0; i < namelen; i++)
1052                 var->var.VariableName[i] = dentry->d_name.name[i];
1053
1054         var->var.VariableName[i] = '\0';
1055
1056         inode->i_private = var;
1057         var->efivars = efivars;
1058         var->kobj.kset = efivars->kset;
1059
1060         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1061                              dentry->d_name.name);
1062         if (err)
1063                 goto out;
1064
1065         kobject_uevent(&var->kobj, KOBJ_ADD);
1066         spin_lock_irq(&efivars->lock);
1067         list_add(&var->list, &efivars->list);
1068         spin_unlock_irq(&efivars->lock);
1069         d_instantiate(dentry, inode);
1070         dget(dentry);
1071 out:
1072         if (err) {
1073                 kfree(var);
1074                 iput(inode);
1075         }
1076         return err;
1077 }
1078
1079 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1080 {
1081         struct efivar_entry *var = dentry->d_inode->i_private;
1082         struct efivars *efivars = var->efivars;
1083         efi_status_t status;
1084
1085         spin_lock_irq(&efivars->lock);
1086
1087         status = efivars->ops->set_variable(var->var.VariableName,
1088                                             &var->var.VendorGuid,
1089                                             0, 0, NULL);
1090
1091         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1092                 list_del(&var->list);
1093                 spin_unlock_irq(&efivars->lock);
1094                 efivar_unregister(var);
1095                 drop_nlink(dentry->d_inode);
1096                 dput(dentry);
1097                 return 0;
1098         }
1099
1100         spin_unlock_irq(&efivars->lock);
1101         return -EINVAL;
1102 };
1103
1104 /*
1105  * Compare two efivarfs file names.
1106  *
1107  * An efivarfs filename is composed of two parts,
1108  *
1109  *      1. A case-sensitive variable name
1110  *      2. A case-insensitive GUID
1111  *
1112  * So we need to perform a case-sensitive match on part 1 and a
1113  * case-insensitive match on part 2.
1114  */
1115 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1116                               const struct dentry *dentry, const struct inode *inode,
1117                               unsigned int len, const char *str,
1118                               const struct qstr *name)
1119 {
1120         int guid = len - GUID_LEN;
1121
1122         if (name->len != len)
1123                 return 1;
1124
1125         /* Case-sensitive compare for the variable name */
1126         if (memcmp(str, name->name, guid))
1127                 return 1;
1128
1129         /* Case-insensitive compare for the GUID */
1130         return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1131 }
1132
1133 static int efivarfs_d_hash(const struct dentry *dentry,
1134                            const struct inode *inode, struct qstr *qstr)
1135 {
1136         unsigned long hash = init_name_hash();
1137         const unsigned char *s = qstr->name;
1138         unsigned int len = qstr->len;
1139
1140         if (!efivarfs_valid_name(s, len))
1141                 return -EINVAL;
1142
1143         while (len-- > GUID_LEN)
1144                 hash = partial_name_hash(*s++, hash);
1145
1146         /* GUID is case-insensitive. */
1147         while (len--)
1148                 hash = partial_name_hash(tolower(*s++), hash);
1149
1150         qstr->hash = end_name_hash(hash);
1151         return 0;
1152 }
1153
1154 /*
1155  * Retaining negative dentries for an in-memory filesystem just wastes
1156  * memory and lookup time: arrange for them to be deleted immediately.
1157  */
1158 static int efivarfs_delete_dentry(const struct dentry *dentry)
1159 {
1160         return 1;
1161 }
1162
1163 static struct dentry_operations efivarfs_d_ops = {
1164         .d_compare = efivarfs_d_compare,
1165         .d_hash = efivarfs_d_hash,
1166         .d_delete = efivarfs_delete_dentry,
1167 };
1168
1169 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1170 {
1171         struct dentry *d;
1172         struct qstr q;
1173         int err;
1174
1175         q.name = name;
1176         q.len = strlen(name);
1177
1178         err = efivarfs_d_hash(NULL, NULL, &q);
1179         if (err)
1180                 return ERR_PTR(err);
1181
1182         d = d_alloc(parent, &q);
1183         if (d)
1184                 return d;
1185
1186         return ERR_PTR(-ENOMEM);
1187 }
1188
1189 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1190 {
1191         struct inode *inode = NULL;
1192         struct dentry *root;
1193         struct efivar_entry *entry, *n;
1194         struct efivars *efivars = &__efivars;
1195         char *name;
1196         int err = -ENOMEM;
1197
1198         efivarfs_sb = sb;
1199
1200         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1201         sb->s_blocksize         = PAGE_CACHE_SIZE;
1202         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1203         sb->s_magic             = EFIVARFS_MAGIC;
1204         sb->s_op                = &efivarfs_ops;
1205         sb->s_d_op              = &efivarfs_d_ops;
1206         sb->s_time_gran         = 1;
1207
1208         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1209         if (!inode)
1210                 return -ENOMEM;
1211         inode->i_op = &efivarfs_dir_inode_operations;
1212
1213         root = d_make_root(inode);
1214         sb->s_root = root;
1215         if (!root)
1216                 return -ENOMEM;
1217
1218         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1219                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1220                 unsigned long size = 0;
1221                 int len, i;
1222
1223                 inode = NULL;
1224
1225                 len = utf16_strlen(entry->var.VariableName);
1226
1227                 /* name, plus '-', plus GUID, plus NUL*/
1228                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1229                 if (!name)
1230                         goto fail;
1231
1232                 for (i = 0; i < len; i++)
1233                         name[i] = entry->var.VariableName[i] & 0xFF;
1234
1235                 name[len] = '-';
1236
1237                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1238
1239                 name[len+GUID_LEN+1] = '\0';
1240
1241                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1242                                           S_IFREG | 0644, 0);
1243                 if (!inode)
1244                         goto fail_name;
1245
1246                 dentry = efivarfs_alloc_dentry(root, name);
1247                 if (IS_ERR(dentry)) {
1248                         err = PTR_ERR(dentry);
1249                         goto fail_inode;
1250                 }
1251
1252                 /* copied by the above to local storage in the dentry. */
1253                 kfree(name);
1254
1255                 spin_lock_irq(&efivars->lock);
1256                 efivars->ops->get_variable(entry->var.VariableName,
1257                                            &entry->var.VendorGuid,
1258                                            &entry->var.Attributes,
1259                                            &size,
1260                                            NULL);
1261                 spin_unlock_irq(&efivars->lock);
1262
1263                 mutex_lock(&inode->i_mutex);
1264                 inode->i_private = entry;
1265                 i_size_write(inode, size + sizeof(entry->var.Attributes));
1266                 mutex_unlock(&inode->i_mutex);
1267                 d_add(dentry, inode);
1268         }
1269
1270         return 0;
1271
1272 fail_inode:
1273         iput(inode);
1274 fail_name:
1275         kfree(name);
1276 fail:
1277         return err;
1278 }
1279
1280 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1281                                     int flags, const char *dev_name, void *data)
1282 {
1283         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1284 }
1285
1286 static void efivarfs_kill_sb(struct super_block *sb)
1287 {
1288         kill_litter_super(sb);
1289         efivarfs_sb = NULL;
1290 }
1291
1292 static struct file_system_type efivarfs_type = {
1293         .name    = "efivarfs",
1294         .mount   = efivarfs_mount,
1295         .kill_sb = efivarfs_kill_sb,
1296 };
1297 MODULE_ALIAS_FS("efivarfs");
1298
1299 /*
1300  * Handle negative dentry.
1301  */
1302 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1303                                       unsigned int flags)
1304 {
1305         if (dentry->d_name.len > NAME_MAX)
1306                 return ERR_PTR(-ENAMETOOLONG);
1307         d_add(dentry, NULL);
1308         return NULL;
1309 }
1310
1311 static const struct inode_operations efivarfs_dir_inode_operations = {
1312         .lookup = efivarfs_lookup,
1313         .unlink = efivarfs_unlink,
1314         .create = efivarfs_create,
1315 };
1316
1317 #ifdef CONFIG_EFI_VARS_PSTORE
1318
1319 static int efi_pstore_open(struct pstore_info *psi)
1320 {
1321         struct efivars *efivars = psi->data;
1322
1323         spin_lock_irq(&efivars->lock);
1324         efivars->walk_entry = list_first_entry(&efivars->list,
1325                                                struct efivar_entry, list);
1326         return 0;
1327 }
1328
1329 static int efi_pstore_close(struct pstore_info *psi)
1330 {
1331         struct efivars *efivars = psi->data;
1332
1333         spin_unlock_irq(&efivars->lock);
1334         return 0;
1335 }
1336
1337 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1338                                int *count, struct timespec *timespec,
1339                                char **buf, struct pstore_info *psi)
1340 {
1341         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1342         struct efivars *efivars = psi->data;
1343         char name[DUMP_NAME_LEN];
1344         int i;
1345         int cnt;
1346         unsigned int part, size;
1347         unsigned long time;
1348
1349         while (&efivars->walk_entry->list != &efivars->list) {
1350                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1351                                  vendor)) {
1352                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1353                                 name[i] = efivars->walk_entry->var.VariableName[i];
1354                         }
1355                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1356                                    type, &part, &cnt, &time) == 4) {
1357                                 *id = part;
1358                                 *count = cnt;
1359                                 timespec->tv_sec = time;
1360                                 timespec->tv_nsec = 0;
1361                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1362                                    type, &part, &time) == 3) {
1363                                 /*
1364                                  * Check if an old format,
1365                                  * which doesn't support holding
1366                                  * multiple logs, remains.
1367                                  */
1368                                 *id = part;
1369                                 *count = 0;
1370                                 timespec->tv_sec = time;
1371                                 timespec->tv_nsec = 0;
1372                         } else {
1373                                 efivars->walk_entry = list_entry(
1374                                                 efivars->walk_entry->list.next,
1375                                                 struct efivar_entry, list);
1376                                 continue;
1377                         }
1378
1379                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1380                         size = efivars->walk_entry->var.DataSize;
1381                         *buf = kmalloc(size, GFP_KERNEL);
1382                         if (*buf == NULL)
1383                                 return -ENOMEM;
1384                         memcpy(*buf, efivars->walk_entry->var.Data,
1385                                size);
1386                         efivars->walk_entry = list_entry(
1387                                         efivars->walk_entry->list.next,
1388                                         struct efivar_entry, list);
1389                         return size;
1390                 }
1391                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1392                                                  struct efivar_entry, list);
1393         }
1394         return 0;
1395 }
1396
1397 static int efi_pstore_write(enum pstore_type_id type,
1398                 enum kmsg_dump_reason reason, u64 *id,
1399                 unsigned int part, int count, size_t size,
1400                 struct pstore_info *psi)
1401 {
1402         char name[DUMP_NAME_LEN];
1403         efi_char16_t efi_name[DUMP_NAME_LEN];
1404         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1405         struct efivars *efivars = psi->data;
1406         int i, ret = 0;
1407         efi_status_t status = EFI_NOT_FOUND;
1408         unsigned long flags;
1409
1410         if (pstore_cannot_block_path(reason)) {
1411                 /*
1412                  * If the lock is taken by another cpu in non-blocking path,
1413                  * this driver returns without entering firmware to avoid
1414                  * hanging up.
1415                  */
1416                 if (!spin_trylock_irqsave(&efivars->lock, flags))
1417                         return -EBUSY;
1418         } else
1419                 spin_lock_irqsave(&efivars->lock, flags);
1420
1421         /*
1422          * Check if there is a space enough to log.
1423          * size: a size of logging data
1424          * DUMP_NAME_LEN * 2: a maximum size of variable name
1425          */
1426
1427         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1428                                          size + DUMP_NAME_LEN * 2);
1429
1430         if (status) {
1431                 spin_unlock_irqrestore(&efivars->lock, flags);
1432                 *id = part;
1433                 return -ENOSPC;
1434         }
1435
1436         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1437                 get_seconds());
1438
1439         for (i = 0; i < DUMP_NAME_LEN; i++)
1440                 efi_name[i] = name[i];
1441
1442         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1443                                    size, psi->buf);
1444
1445         spin_unlock_irqrestore(&efivars->lock, flags);
1446
1447         if (reason == KMSG_DUMP_OOPS)
1448                 schedule_work(&efivar_work);
1449
1450         *id = part;
1451         return ret;
1452 };
1453
1454 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1455                             struct timespec time, struct pstore_info *psi)
1456 {
1457         char name[DUMP_NAME_LEN];
1458         efi_char16_t efi_name[DUMP_NAME_LEN];
1459         char name_old[DUMP_NAME_LEN];
1460         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1461         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1462         struct efivars *efivars = psi->data;
1463         struct efivar_entry *entry, *found = NULL;
1464         int i;
1465
1466         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1467                 time.tv_sec);
1468
1469         spin_lock_irq(&efivars->lock);
1470
1471         for (i = 0; i < DUMP_NAME_LEN; i++)
1472                 efi_name[i] = name[i];
1473
1474         /*
1475          * Clean up an entry with the same name
1476          */
1477
1478         list_for_each_entry(entry, &efivars->list, list) {
1479                 get_var_data_locked(efivars, &entry->var);
1480
1481                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1482                         continue;
1483                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1484                                   utf16_strlen(efi_name))) {
1485                         /*
1486                          * Check if an old format,
1487                          * which doesn't support holding
1488                          * multiple logs, remains.
1489                          */
1490                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1491                                 (unsigned int)id, time.tv_sec);
1492
1493                         for (i = 0; i < DUMP_NAME_LEN; i++)
1494                                 efi_name_old[i] = name_old[i];
1495
1496                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1497                                           utf16_strlen(efi_name_old)))
1498                                 continue;
1499                 }
1500
1501                 /* found */
1502                 found = entry;
1503                 efivars->ops->set_variable(entry->var.VariableName,
1504                                            &entry->var.VendorGuid,
1505                                            PSTORE_EFI_ATTRIBUTES,
1506                                            0, NULL);
1507                 break;
1508         }
1509
1510         if (found)
1511                 list_del(&found->list);
1512
1513         spin_unlock_irq(&efivars->lock);
1514
1515         if (found)
1516                 efivar_unregister(found);
1517
1518         return 0;
1519 }
1520
1521 static struct pstore_info efi_pstore_info = {
1522         .owner          = THIS_MODULE,
1523         .name           = "efi",
1524         .open           = efi_pstore_open,
1525         .close          = efi_pstore_close,
1526         .read           = efi_pstore_read,
1527         .write          = efi_pstore_write,
1528         .erase          = efi_pstore_erase,
1529 };
1530
1531 static void efivar_pstore_register(struct efivars *efivars)
1532 {
1533         efivars->efi_pstore_info = efi_pstore_info;
1534         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1535         if (efivars->efi_pstore_info.buf) {
1536                 efivars->efi_pstore_info.bufsize = 1024;
1537                 efivars->efi_pstore_info.data = efivars;
1538                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1539                 pstore_register(&efivars->efi_pstore_info);
1540         }
1541 }
1542 #else
1543 static void efivar_pstore_register(struct efivars *efivars)
1544 {
1545         return;
1546 }
1547 #endif
1548
1549 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1550                              struct bin_attribute *bin_attr,
1551                              char *buf, loff_t pos, size_t count)
1552 {
1553         struct efi_variable *new_var = (struct efi_variable *)buf;
1554         struct efivars *efivars = bin_attr->private;
1555         struct efivar_entry *search_efivar, *n;
1556         unsigned long strsize1, strsize2;
1557         efi_status_t status = EFI_NOT_FOUND;
1558         int found = 0;
1559
1560         if (!capable(CAP_SYS_ADMIN))
1561                 return -EACCES;
1562
1563         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1564             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1565                 printk(KERN_ERR "efivars: Malformed variable content\n");
1566                 return -EINVAL;
1567         }
1568
1569         spin_lock_irq(&efivars->lock);
1570
1571         /*
1572          * Does this variable already exist?
1573          */
1574         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1575                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1576                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1577                 if (strsize1 == strsize2 &&
1578                         !memcmp(&(search_efivar->var.VariableName),
1579                                 new_var->VariableName, strsize1) &&
1580                         !efi_guidcmp(search_efivar->var.VendorGuid,
1581                                 new_var->VendorGuid)) {
1582                         found = 1;
1583                         break;
1584                 }
1585         }
1586         if (found) {
1587                 spin_unlock_irq(&efivars->lock);
1588                 return -EINVAL;
1589         }
1590
1591         status = check_var_size_locked(efivars, new_var->Attributes,
1592                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
1593
1594         if (status && status != EFI_UNSUPPORTED) {
1595                 spin_unlock_irq(&efivars->lock);
1596                 return efi_status_to_err(status);
1597         }
1598
1599         /* now *really* create the variable via EFI */
1600         status = efivars->ops->set_variable(new_var->VariableName,
1601                                             &new_var->VendorGuid,
1602                                             new_var->Attributes,
1603                                             new_var->DataSize,
1604                                             new_var->Data);
1605
1606         if (status != EFI_SUCCESS) {
1607                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1608                         status);
1609                 spin_unlock_irq(&efivars->lock);
1610                 return -EIO;
1611         }
1612         spin_unlock_irq(&efivars->lock);
1613
1614         /* Create the entry in sysfs.  Locking is not required here */
1615         status = efivar_create_sysfs_entry(efivars,
1616                                            utf16_strsize(new_var->VariableName,
1617                                                          1024),
1618                                            new_var->VariableName,
1619                                            &new_var->VendorGuid);
1620         if (status) {
1621                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1622         }
1623         return count;
1624 }
1625
1626 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1627                              struct bin_attribute *bin_attr,
1628                              char *buf, loff_t pos, size_t count)
1629 {
1630         struct efi_variable *del_var = (struct efi_variable *)buf;
1631         struct efivars *efivars = bin_attr->private;
1632         struct efivar_entry *search_efivar, *n;
1633         unsigned long strsize1, strsize2;
1634         efi_status_t status = EFI_NOT_FOUND;
1635         int found = 0;
1636
1637         if (!capable(CAP_SYS_ADMIN))
1638                 return -EACCES;
1639
1640         spin_lock_irq(&efivars->lock);
1641
1642         /*
1643          * Does this variable already exist?
1644          */
1645         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1646                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1647                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1648                 if (strsize1 == strsize2 &&
1649                         !memcmp(&(search_efivar->var.VariableName),
1650                                 del_var->VariableName, strsize1) &&
1651                         !efi_guidcmp(search_efivar->var.VendorGuid,
1652                                 del_var->VendorGuid)) {
1653                         found = 1;
1654                         break;
1655                 }
1656         }
1657         if (!found) {
1658                 spin_unlock_irq(&efivars->lock);
1659                 return -EINVAL;
1660         }
1661         /* force the Attributes/DataSize to 0 to ensure deletion */
1662         del_var->Attributes = 0;
1663         del_var->DataSize = 0;
1664
1665         status = efivars->ops->set_variable(del_var->VariableName,
1666                                             &del_var->VendorGuid,
1667                                             del_var->Attributes,
1668                                             del_var->DataSize,
1669                                             del_var->Data);
1670
1671         if (status != EFI_SUCCESS) {
1672                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1673                         status);
1674                 spin_unlock_irq(&efivars->lock);
1675                 return -EIO;
1676         }
1677         list_del(&search_efivar->list);
1678         /* We need to release this lock before unregistering. */
1679         spin_unlock_irq(&efivars->lock);
1680         efivar_unregister(search_efivar);
1681
1682         /* It's dead Jim.... */
1683         return count;
1684 }
1685
1686 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1687 {
1688         struct efivar_entry *entry, *n;
1689         struct efivars *efivars = &__efivars;
1690         unsigned long strsize1, strsize2;
1691         bool found = false;
1692
1693         strsize1 = utf16_strsize(variable_name, 1024);
1694         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1695                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1696                 if (strsize1 == strsize2 &&
1697                         !memcmp(variable_name, &(entry->var.VariableName),
1698                                 strsize2) &&
1699                         !efi_guidcmp(entry->var.VendorGuid,
1700                                 *vendor)) {
1701                         found = true;
1702                         break;
1703                 }
1704         }
1705         return found;
1706 }
1707
1708 static void efivar_update_sysfs_entries(struct work_struct *work)
1709 {
1710         struct efivars *efivars = &__efivars;
1711         efi_guid_t vendor;
1712         efi_char16_t *variable_name;
1713         unsigned long variable_name_size = 1024;
1714         efi_status_t status = EFI_NOT_FOUND;
1715         bool found;
1716
1717         /* Add new sysfs entries */
1718         while (1) {
1719                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1720                 if (!variable_name) {
1721                         pr_err("efivars: Memory allocation failed.\n");
1722                         return;
1723                 }
1724
1725                 spin_lock_irq(&efivars->lock);
1726                 found = false;
1727                 while (1) {
1728                         variable_name_size = 1024;
1729                         status = efivars->ops->get_next_variable(
1730                                                         &variable_name_size,
1731                                                         variable_name,
1732                                                         &vendor);
1733                         if (status != EFI_SUCCESS) {
1734                                 break;
1735                         } else {
1736                                 if (!variable_is_present(variable_name,
1737                                     &vendor)) {
1738                                         found = true;
1739                                         break;
1740                                 }
1741                         }
1742                 }
1743                 spin_unlock_irq(&efivars->lock);
1744
1745                 if (!found) {
1746                         kfree(variable_name);
1747                         break;
1748                 } else
1749                         efivar_create_sysfs_entry(efivars,
1750                                                   variable_name_size,
1751                                                   variable_name, &vendor);
1752         }
1753 }
1754
1755 /*
1756  * Let's not leave out systab information that snuck into
1757  * the efivars driver
1758  */
1759 static ssize_t systab_show(struct kobject *kobj,
1760                            struct kobj_attribute *attr, char *buf)
1761 {
1762         char *str = buf;
1763
1764         if (!kobj || !buf)
1765                 return -EINVAL;
1766
1767         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1768                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1769         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1770                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1771         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1772                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1773         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1774                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1775         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1776                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1777         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1778                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1779         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1780                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1781
1782         return str - buf;
1783 }
1784
1785 static struct kobj_attribute efi_attr_systab =
1786                         __ATTR(systab, 0400, systab_show, NULL);
1787
1788 static struct attribute *efi_subsys_attrs[] = {
1789         &efi_attr_systab.attr,
1790         NULL,   /* maybe more in the future? */
1791 };
1792
1793 static struct attribute_group efi_subsys_attr_group = {
1794         .attrs = efi_subsys_attrs,
1795 };
1796
1797 static struct kobject *efi_kobj;
1798
1799 /*
1800  * efivar_create_sysfs_entry()
1801  * Requires:
1802  *    variable_name_size = number of bytes required to hold
1803  *                         variable_name (not counting the NULL
1804  *                         character at the end.
1805  *    efivars->lock is not held on entry or exit.
1806  * Returns 1 on failure, 0 on success
1807  */
1808 static int
1809 efivar_create_sysfs_entry(struct efivars *efivars,
1810                           unsigned long variable_name_size,
1811                           efi_char16_t *variable_name,
1812                           efi_guid_t *vendor_guid)
1813 {
1814         int i, short_name_size;
1815         char *short_name;
1816         struct efivar_entry *new_efivar;
1817
1818         /*
1819          * Length of the variable bytes in ASCII, plus the '-' separator,
1820          * plus the GUID, plus trailing NUL
1821          */
1822         short_name_size = variable_name_size / sizeof(efi_char16_t)
1823                                 + 1 + GUID_LEN + 1;
1824
1825         short_name = kzalloc(short_name_size, GFP_KERNEL);
1826         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1827
1828         if (!short_name || !new_efivar)  {
1829                 kfree(short_name);
1830                 kfree(new_efivar);
1831                 return 1;
1832         }
1833
1834         new_efivar->efivars = efivars;
1835         memcpy(new_efivar->var.VariableName, variable_name,
1836                 variable_name_size);
1837         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1838
1839         /* Convert Unicode to normal chars (assume top bits are 0),
1840            ala UTF-8 */
1841         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1842                 short_name[i] = variable_name[i] & 0xFF;
1843         }
1844         /* This is ugly, but necessary to separate one vendor's
1845            private variables from another's.         */
1846
1847         *(short_name + strlen(short_name)) = '-';
1848         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1849
1850         new_efivar->kobj.kset = efivars->kset;
1851         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1852                                  "%s", short_name);
1853         if (i) {
1854                 kfree(short_name);
1855                 kfree(new_efivar);
1856                 return 1;
1857         }
1858
1859         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1860         kfree(short_name);
1861         short_name = NULL;
1862
1863         spin_lock_irq(&efivars->lock);
1864         list_add(&new_efivar->list, &efivars->list);
1865         spin_unlock_irq(&efivars->lock);
1866
1867         return 0;
1868 }
1869
1870 static int
1871 create_efivars_bin_attributes(struct efivars *efivars)
1872 {
1873         struct bin_attribute *attr;
1874         int error;
1875
1876         /* new_var */
1877         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1878         if (!attr)
1879                 return -ENOMEM;
1880
1881         attr->attr.name = "new_var";
1882         attr->attr.mode = 0200;
1883         attr->write = efivar_create;
1884         attr->private = efivars;
1885         efivars->new_var = attr;
1886
1887         /* del_var */
1888         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1889         if (!attr) {
1890                 error = -ENOMEM;
1891                 goto out_free;
1892         }
1893         attr->attr.name = "del_var";
1894         attr->attr.mode = 0200;
1895         attr->write = efivar_delete;
1896         attr->private = efivars;
1897         efivars->del_var = attr;
1898
1899         sysfs_bin_attr_init(efivars->new_var);
1900         sysfs_bin_attr_init(efivars->del_var);
1901
1902         /* Register */
1903         error = sysfs_create_bin_file(&efivars->kset->kobj,
1904                                       efivars->new_var);
1905         if (error) {
1906                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1907                         " due to error %d\n", error);
1908                 goto out_free;
1909         }
1910         error = sysfs_create_bin_file(&efivars->kset->kobj,
1911                                       efivars->del_var);
1912         if (error) {
1913                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1914                         " due to error %d\n", error);
1915                 sysfs_remove_bin_file(&efivars->kset->kobj,
1916                                       efivars->new_var);
1917                 goto out_free;
1918         }
1919
1920         return 0;
1921 out_free:
1922         kfree(efivars->del_var);
1923         efivars->del_var = NULL;
1924         kfree(efivars->new_var);
1925         efivars->new_var = NULL;
1926         return error;
1927 }
1928
1929 void unregister_efivars(struct efivars *efivars)
1930 {
1931         struct efivar_entry *entry, *n;
1932
1933         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1934                 spin_lock_irq(&efivars->lock);
1935                 list_del(&entry->list);
1936                 spin_unlock_irq(&efivars->lock);
1937                 efivar_unregister(entry);
1938         }
1939         if (efivars->new_var)
1940                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1941         if (efivars->del_var)
1942                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1943         kfree(efivars->new_var);
1944         kfree(efivars->del_var);
1945         kobject_put(efivars->kobject);
1946         kset_unregister(efivars->kset);
1947 }
1948 EXPORT_SYMBOL_GPL(unregister_efivars);
1949
1950 int register_efivars(struct efivars *efivars,
1951                      const struct efivar_operations *ops,
1952                      struct kobject *parent_kobj)
1953 {
1954         efi_status_t status = EFI_NOT_FOUND;
1955         efi_guid_t vendor_guid;
1956         efi_char16_t *variable_name;
1957         unsigned long variable_name_size = 1024;
1958         int error = 0;
1959
1960         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1961         if (!variable_name) {
1962                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1963                 return -ENOMEM;
1964         }
1965
1966         spin_lock_init(&efivars->lock);
1967         INIT_LIST_HEAD(&efivars->list);
1968         efivars->ops = ops;
1969
1970         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1971         if (!efivars->kset) {
1972                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1973                 error = -ENOMEM;
1974                 goto out;
1975         }
1976
1977         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1978         if (!efivars->kobject) {
1979                 pr_err("efivars: Subsystem registration failed.\n");
1980                 error = -ENOMEM;
1981                 kset_unregister(efivars->kset);
1982                 goto out;
1983         }
1984
1985         /*
1986          * Per EFI spec, the maximum storage allocated for both
1987          * the variable name and variable data is 1024 bytes.
1988          */
1989
1990         do {
1991                 variable_name_size = 1024;
1992
1993                 status = ops->get_next_variable(&variable_name_size,
1994                                                 variable_name,
1995                                                 &vendor_guid);
1996                 switch (status) {
1997                 case EFI_SUCCESS:
1998                         efivar_create_sysfs_entry(efivars,
1999                                                   variable_name_size,
2000                                                   variable_name,
2001                                                   &vendor_guid);
2002                         break;
2003                 case EFI_NOT_FOUND:
2004                         break;
2005                 default:
2006                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
2007                                 status);
2008                         status = EFI_NOT_FOUND;
2009                         break;
2010                 }
2011         } while (status != EFI_NOT_FOUND);
2012
2013         error = create_efivars_bin_attributes(efivars);
2014         if (error)
2015                 unregister_efivars(efivars);
2016
2017         if (!efivars_pstore_disable)
2018                 efivar_pstore_register(efivars);
2019
2020         register_filesystem(&efivarfs_type);
2021
2022 out:
2023         kfree(variable_name);
2024
2025         return error;
2026 }
2027 EXPORT_SYMBOL_GPL(register_efivars);
2028
2029 /*
2030  * For now we register the efi subsystem with the firmware subsystem
2031  * and the vars subsystem with the efi subsystem.  In the future, it
2032  * might make sense to split off the efi subsystem into its own
2033  * driver, but for now only efivars will register with it, so just
2034  * include it here.
2035  */
2036
2037 static int __init
2038 efivars_init(void)
2039 {
2040         int error = 0;
2041
2042         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2043                EFIVARS_DATE);
2044
2045         if (!efi_enabled(EFI_RUNTIME_SERVICES))
2046                 return 0;
2047
2048         /* For now we'll register the efi directory at /sys/firmware/efi */
2049         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2050         if (!efi_kobj) {
2051                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2052                 return -ENOMEM;
2053         }
2054
2055         ops.get_variable = efi.get_variable;
2056         ops.set_variable = efi.set_variable;
2057         ops.get_next_variable = efi.get_next_variable;
2058         ops.query_variable_info = efi.query_variable_info;
2059
2060         error = register_efivars(&__efivars, &ops, efi_kobj);
2061         if (error)
2062                 goto err_put;
2063
2064         /* Don't forget the systab entry */
2065         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2066         if (error) {
2067                 printk(KERN_ERR
2068                        "efivars: Sysfs attribute export failed with error %d.\n",
2069                        error);
2070                 goto err_unregister;
2071         }
2072
2073         return 0;
2074
2075 err_unregister:
2076         unregister_efivars(&__efivars);
2077 err_put:
2078         kobject_put(efi_kobj);
2079         return error;
2080 }
2081
2082 static void __exit
2083 efivars_exit(void)
2084 {
2085         cancel_work_sync(&efivar_work);
2086
2087         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2088                 unregister_efivars(&__efivars);
2089                 kobject_put(efi_kobj);
2090         }
2091 }
2092
2093 module_init(efivars_init);
2094 module_exit(efivars_exit);
2095