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 /*
 107  * The maximum size of VariableName + Data = 1024
 108  * Therefore, it's reasonable to save that much
 109  * space in each part of the structure,
 110  * and we use a page for reading/writing.
 111  */
 112
 113 struct efi_variable {
 114         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 115         efi_guid_t    VendorGuid;
 116         unsigned long DataSize;
 117         __u8          Data[1024];
 118         efi_status_t  Status;
 119         __u32         Attributes;
 120 } __attribute__((packed));
 121
 122 struct efivar_entry {
 123         struct efivars *efivars;
 124         struct efi_variable var;
 125         struct list_head list;
 126         struct kobject kobj;
 127 };
 128
 129 struct efivar_attribute {
 130         struct attribute attr;
 131         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 132         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 133 };
 134
 135 static struct efivars __efivars;
 136 static struct efivar_operations ops;
 137
 138 #define PSTORE_EFI_ATTRIBUTES \
 139         (EFI_VARIABLE_NON_VOLATILE | \
 140          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 141          EFI_VARIABLE_RUNTIME_ACCESS)
 142
 143 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 144 struct efivar_attribute efivar_attr_##_name = { \
 145         .attr = {.name = __stringify(_name), .mode = _mode}, \
 146         .show = _show, \
 147         .store = _store, \
 148 };
 149
 150 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 151 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 152
 153 /*
 154  * Prototype for sysfs creation function
 155  */
 156 static int
 157 efivar_create_sysfs_entry(struct efivars *efivars,
 158                           unsigned long variable_name_size,
 159                           efi_char16_t *variable_name,
 160                           efi_guid_t *vendor_guid);
 161
 162 /*
 163  * Prototype for workqueue functions updating sysfs entry
 164  */
 165
 166 static void efivar_update_sysfs_entries(struct work_struct *);
 167 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
 168
 169 /* Return the number of unicode characters in data */
 170 static unsigned long
 171 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 172 {
 173         unsigned long length = 0;
 174
 175         while (*s++ != 0 && length < maxlength)
 176                 length++;
 177         return length;
 178 }
 179
 180 static inline unsigned long
 181 utf16_strlen(efi_char16_t *s)
 182 {
 183         return utf16_strnlen(s, ~0UL);
 184 }
 185
 186 /*
 187  * Return the number of bytes is the length of this string
 188  * Note: this is NOT the same as the number of unicode characters
 189  */
 190 static inline unsigned long
 191 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 192 {
 193         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 194 }
 195
 196 static inline int
 197 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 198 {
 199         while (1) {
 200                 if (len == 0)
 201                         return 0;
 202                 if (*a < *b)
 203                         return -1;
 204                 if (*a > *b)
 205                         return 1;
 206                 if (*a == 0) /* implies *b == 0 */
 207                         return 0;
 208                 a++;
 209                 b++;
 210                 len--;
 211         }
 212 }
 213
 214 static bool
 215 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 216                      unsigned long len)
 217 {
 218         struct efi_generic_dev_path *node;
 219         int offset = 0;
 220
 221         node = (struct efi_generic_dev_path *)buffer;
 222
 223         if (len < sizeof(*node))
 224                 return false;
 225
 226         while (offset <= len - sizeof(*node) &&
 227                node->length >= sizeof(*node) &&
 228                 node->length <= len - offset) {
 229                 offset += node->length;
 230
 231                 if ((node->type == EFI_DEV_END_PATH ||
 232                      node->type == EFI_DEV_END_PATH2) &&
 233                     node->sub_type == EFI_DEV_END_ENTIRE)
 234                         return true;
 235
 236                 node = (struct efi_generic_dev_path *)(buffer + offset);
 237         }
 238
 239         /*
 240          * If we're here then either node->length pointed past the end
 241          * of the buffer or we reached the end of the buffer without
 242          * finding a device path end node.
 243          */
 244         return false;
 245 }
 246
 247 static bool
 248 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 249                     unsigned long len)
 250 {
 251         /* An array of 16-bit integers */
 252         if ((len % 2) != 0)
 253                 return false;
 254
 255         return true;
 256 }
 257
 258 static bool
 259 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 260                      unsigned long len)
 261 {
 262         u16 filepathlength;
 263         int i, desclength = 0, namelen;
 264
 265         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 266
 267         /* Either "Boot" or "Driver" followed by four digits of hex */
 268         for (i = match; i < match+4; i++) {
 269                 if (var->VariableName[i] > 127 ||
 270                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 271                         return true;
 272         }
 273
 274         /* Reject it if there's 4 digits of hex and then further content */
 275         if (namelen > match + 4)
 276                 return false;
 277
 278         /* A valid entry must be at least 8 bytes */
 279         if (len < 8)
 280                 return false;
 281
 282         filepathlength = buffer[4] | buffer[5] << 8;
 283
 284         /*
 285          * There's no stored length for the description, so it has to be
 286          * found by hand
 287          */
 288         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 289
 290         /* Each boot entry must have a descriptor */
 291         if (!desclength)
 292                 return false;
 293
 294         /*
 295          * If the sum of the length of the description, the claimed filepath
 296          * length and the original header are greater than the length of the
 297          * variable, it's malformed
 298          */
 299         if ((desclength + filepathlength + 6) > len)
 300                 return false;
 301
 302         /*
 303          * And, finally, check the filepath
 304          */
 305         return validate_device_path(var, match, buffer + desclength + 6,
 306                                     filepathlength);
 307 }
 308
 309 static bool
 310 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 311                 unsigned long len)
 312 {
 313         /* A single 16-bit integer */
 314         if (len != 2)
 315                 return false;
 316
 317         return true;
 318 }
 319
 320 static bool
 321 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 322                       unsigned long len)
 323 {
 324         int i;
 325
 326         for (i = 0; i < len; i++) {
 327                 if (buffer[i] > 127)
 328                         return false;
 329
 330                 if (buffer[i] == 0)
 331                         return true;
 332         }
 333
 334         return false;
 335 }
 336
 337 struct variable_validate {
 338         char *name;
 339         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 340                          unsigned long len);
 341 };
 342
 343 static const struct variable_validate variable_validate[] = {
 344         { "BootNext", validate_uint16 },
 345         { "BootOrder", validate_boot_order },
 346         { "DriverOrder", validate_boot_order },
 347         { "Boot*", validate_load_option },
 348         { "Driver*", validate_load_option },
 349         { "ConIn", validate_device_path },
 350         { "ConInDev", validate_device_path },
 351         { "ConOut", validate_device_path },
 352         { "ConOutDev", validate_device_path },
 353         { "ErrOut", validate_device_path },
 354         { "ErrOutDev", validate_device_path },
 355         { "Timeout", validate_uint16 },
 356         { "Lang", validate_ascii_string },
 357         { "PlatformLang", validate_ascii_string },
 358         { "", NULL },
 359 };
 360
 361 static bool
 362 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 363 {
 364         int i;
 365         u16 *unicode_name = var->VariableName;
 366
 367         for (i = 0; variable_validate[i].validate != NULL; i++) {
 368                 const char *name = variable_validate[i].name;
 369                 int match;
 370
 371                 for (match = 0; ; match++) {
 372                         char c = name[match];
 373                         u16 u = unicode_name[match];
 374
 375                         /* All special variables are plain ascii */
 376                         if (u > 127)
 377                                 return true;
 378
 379                         /* Wildcard in the matching name means we've matched */
 380                         if (c == '*')
 381                                 return variable_validate[i].validate(var,
 382                                                              match, data, len);
 383
 384                         /* Case sensitive match */
 385                         if (c != u)
 386                                 break;
 387
 388                         /* Reached the end of the string while matching */
 389                         if (!c)
 390                                 return variable_validate[i].validate(var,
 391                                                              match, data, len);
 392                 }
 393         }
 394
 395         return true;
 396 }
 397
 398 static efi_status_t
 399 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 400 {
 401         efi_status_t status;
 402
 403         var->DataSize = 1024;
 404         status = efivars->ops->get_variable(var->VariableName,
 405                                             &var->VendorGuid,
 406                                             &var->Attributes,
 407                                             &var->DataSize,
 408                                             var->Data);
 409         return status;
 410 }
 411
 412 static efi_status_t
 413 get_var_data(struct efivars *efivars, struct efi_variable *var)
 414 {
 415         efi_status_t status;
 416         unsigned long flags;
 417
 418         spin_lock_irqsave(&efivars->lock, flags);
 419         status = get_var_data_locked(efivars, var);
 420         spin_unlock_irqrestore(&efivars->lock, flags);
 421
 422         if (status != EFI_SUCCESS) {
 423                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 424                         status);
 425         }
 426         return status;
 427 }
 428
 429 static efi_status_t
 430 check_var_size_locked(struct efivars *efivars, u32 attributes,
 431                         unsigned long size)
 432 {
 433         u64 storage_size, remaining_size, max_size;
 434         efi_status_t status;
 435         const struct efivar_operations *fops = efivars->ops;
 436
 437         if (!efivars->ops->query_variable_info)
 438                 return EFI_UNSUPPORTED;
 439
 440         status = fops->query_variable_info(attributes, &storage_size,
 441                                            &remaining_size, &max_size);
 442
 443         if (status != EFI_SUCCESS)
 444                 return status;
 445
 446         if (!storage_size || size > remaining_size || size > max_size ||
 447             (remaining_size - size) < (storage_size / 2))
 448                 return EFI_OUT_OF_RESOURCES;
 449
 450         return status;
 451 }
 452
 453
 454 static efi_status_t
 455 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
 456 {
 457         efi_status_t status;
 458         unsigned long flags;
 459
 460         spin_lock_irqsave(&efivars->lock, flags);
 461         status = check_var_size_locked(efivars, attributes, size);
 462         spin_unlock_irqrestore(&efivars->lock, flags);
 463
 464         return status;
 465 }
 466
 467 static ssize_t
 468 efivar_guid_read(struct efivar_entry *entry, char *buf)
 469 {
 470         struct efi_variable *var = &entry->var;
 471         char *str = buf;
 472
 473         if (!entry || !buf)
 474                 return 0;
 475
 476         efi_guid_unparse(&var->VendorGuid, str);
 477         str += strlen(str);
 478         str += sprintf(str, "\n");
 479
 480         return str - buf;
 481 }
 482
 483 static ssize_t
 484 efivar_attr_read(struct efivar_entry *entry, char *buf)
 485 {
 486         struct efi_variable *var = &entry->var;
 487         char *str = buf;
 488         efi_status_t status;
 489
 490         if (!entry || !buf)
 491                 return -EINVAL;
 492
 493         status = get_var_data(entry->efivars, var);
 494         if (status != EFI_SUCCESS)
 495                 return -EIO;
 496
 497         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 498                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 499         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 500                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 501         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 502                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 503         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 504                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 505         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 506                 str += sprintf(str,
 507                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 508         if (var->Attributes &
 509                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 510                 str += sprintf(str,
 511                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 512         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 513                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 514         return str - buf;
 515 }
 516
 517 static ssize_t
 518 efivar_size_read(struct efivar_entry *entry, char *buf)
 519 {
 520         struct efi_variable *var = &entry->var;
 521         char *str = buf;
 522         efi_status_t status;
 523
 524         if (!entry || !buf)
 525                 return -EINVAL;
 526
 527         status = get_var_data(entry->efivars, var);
 528         if (status != EFI_SUCCESS)
 529                 return -EIO;
 530
 531         str += sprintf(str, "0x%lx\n", var->DataSize);
 532         return str - buf;
 533 }
 534
 535 static ssize_t
 536 efivar_data_read(struct efivar_entry *entry, char *buf)
 537 {
 538         struct efi_variable *var = &entry->var;
 539         efi_status_t status;
 540
 541         if (!entry || !buf)
 542                 return -EINVAL;
 543
 544         status = get_var_data(entry->efivars, var);
 545         if (status != EFI_SUCCESS)
 546                 return -EIO;
 547
 548         memcpy(buf, var->Data, var->DataSize);
 549         return var->DataSize;
 550 }
 551 /*
 552  * We allow each variable to be edited via rewriting the
 553  * entire efi variable structure.
 554  */
 555 static ssize_t
 556 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 557 {
 558         struct efi_variable *new_var, *var = &entry->var;
 559         struct efivars *efivars = entry->efivars;
 560         efi_status_t status = EFI_NOT_FOUND;
 561
 562         if (count != sizeof(struct efi_variable))
 563                 return -EINVAL;
 564
 565         new_var = (struct efi_variable *)buf;
 566         /*
 567          * If only updating the variable data, then the name
 568          * and guid should remain the same
 569          */
 570         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 571                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 572                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 573                 return -EINVAL;
 574         }
 575
 576         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 577                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 578                 return -EINVAL;
 579         }
 580
 581         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 582             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 583                 printk(KERN_ERR "efivars: Malformed variable content\n");
 584                 return -EINVAL;
 585         }
 586
 587         spin_lock_irq(&efivars->lock);
 588
 589         status = check_var_size_locked(efivars, new_var->Attributes,
 590                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 591
 592         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 593                 status = efivars->ops->set_variable(new_var->VariableName,
 594                                                     &new_var->VendorGuid,
 595                                                     new_var->Attributes,
 596                                                     new_var->DataSize,
 597                                                     new_var->Data);
 598
 599         spin_unlock_irq(&efivars->lock);
 600
 601         if (status != EFI_SUCCESS) {
 602                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 603                         status);
 604                 return -EIO;
 605         }
 606
 607         memcpy(&entry->var, new_var, count);
 608         return count;
 609 }
 610
 611 static ssize_t
 612 efivar_show_raw(struct efivar_entry *entry, char *buf)
 613 {
 614         struct efi_variable *var = &entry->var;
 615         efi_status_t status;
 616
 617         if (!entry || !buf)
 618                 return 0;
 619
 620         status = get_var_data(entry->efivars, var);
 621         if (status != EFI_SUCCESS)
 622                 return -EIO;
 623
 624         memcpy(buf, var, sizeof(*var));
 625         return sizeof(*var);
 626 }
 627
 628 /*
 629  * Generic read/write functions that call the specific functions of
 630  * the attributes...
 631  */
 632 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 633                                 char *buf)
 634 {
 635         struct efivar_entry *var = to_efivar_entry(kobj);
 636         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 637         ssize_t ret = -EIO;
 638
 639         if (!capable(CAP_SYS_ADMIN))
 640                 return -EACCES;
 641
 642         if (efivar_attr->show) {
 643                 ret = efivar_attr->show(var, buf);
 644         }
 645         return ret;
 646 }
 647
 648 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 649                                 const char *buf, size_t count)
 650 {
 651         struct efivar_entry *var = to_efivar_entry(kobj);
 652         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 653         ssize_t ret = -EIO;
 654
 655         if (!capable(CAP_SYS_ADMIN))
 656                 return -EACCES;
 657
 658         if (efivar_attr->store)
 659                 ret = efivar_attr->store(var, buf, count);
 660
 661         return ret;
 662 }
 663
 664 static const struct sysfs_ops efivar_attr_ops = {
 665         .show = efivar_attr_show,
 666         .store = efivar_attr_store,
 667 };
 668
 669 static void efivar_release(struct kobject *kobj)
 670 {
 671         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 672         kfree(var);
 673 }
 674
 675 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 676 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 677 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 678 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 679 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 680
 681 static struct attribute *def_attrs[] = {
 682         &efivar_attr_guid.attr,
 683         &efivar_attr_size.attr,
 684         &efivar_attr_attributes.attr,
 685         &efivar_attr_data.attr,
 686         &efivar_attr_raw_var.attr,
 687         NULL,
 688 };
 689
 690 static struct kobj_type efivar_ktype = {
 691         .release = efivar_release,
 692         .sysfs_ops = &efivar_attr_ops,
 693         .default_attrs = def_attrs,
 694 };
 695
 696 static inline void
 697 efivar_unregister(struct efivar_entry *var)
 698 {
 699         kobject_put(&var->kobj);
 700 }
 701
 702 static int efivarfs_file_open(struct inode *inode, struct file *file)
 703 {
 704         file->private_data = inode->i_private;
 705         return 0;
 706 }
 707
 708 static int efi_status_to_err(efi_status_t status)
 709 {
 710         int err;
 711
 712         switch (status) {
 713         case EFI_INVALID_PARAMETER:
 714                 err = -EINVAL;
 715                 break;
 716         case EFI_OUT_OF_RESOURCES:
 717                 err = -ENOSPC;
 718                 break;
 719         case EFI_DEVICE_ERROR:
 720                 err = -EIO;
 721                 break;
 722         case EFI_WRITE_PROTECTED:
 723                 err = -EROFS;
 724                 break;
 725         case EFI_SECURITY_VIOLATION:
 726                 err = -EACCES;
 727                 break;
 728         case EFI_NOT_FOUND:
 729                 err = -EIO;
 730                 break;
 731         default:
 732                 err = -EINVAL;
 733         }
 734
 735         return err;
 736 }
 737
 738 static ssize_t efivarfs_file_write(struct file *file,
 739                 const char __user *userbuf, size_t count, loff_t *ppos)
 740 {
 741         struct efivar_entry *var = file->private_data;
 742         struct efivars *efivars;
 743         efi_status_t status;
 744         void *data;
 745         u32 attributes;
 746         struct inode *inode = file->f_mapping->host;
 747         unsigned long datasize = count - sizeof(attributes);
 748         unsigned long newdatasize, varsize;
 749         ssize_t bytes = 0;
 750
 751         if (count < sizeof(attributes))
 752                 return -EINVAL;
 753
 754         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 755                 return -EFAULT;
 756
 757         if (attributes & ~(EFI_VARIABLE_MASK))
 758                 return -EINVAL;
 759
 760         efivars = var->efivars;
 761
 762         /*
 763          * Ensure that the user can't allocate arbitrarily large
 764          * amounts of memory. Pick a default size of 64K if
 765          * QueryVariableInfo() isn't supported by the firmware.
 766          */
 767
 768         varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
 769         status = check_var_size(efivars, attributes, varsize);
 770
 771         if (status != EFI_SUCCESS) {
 772                 if (status != EFI_UNSUPPORTED)
 773                         return efi_status_to_err(status);
 774
 775                 if (datasize > 65536)
 776                         return -ENOSPC;
 777         }
 778
 779         data = kmalloc(datasize, GFP_KERNEL);
 780         if (!data)
 781                 return -ENOMEM;
 782
 783         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 784                 bytes = -EFAULT;
 785                 goto out;
 786         }
 787
 788         if (validate_var(&var->var, data, datasize) == false) {
 789                 bytes = -EINVAL;
 790                 goto out;
 791         }
 792
 793         /*
 794          * The lock here protects the get_variable call, the conditional
 795          * set_variable call, and removal of the variable from the efivars
 796          * list (in the case of an authenticated delete).
 797          */
 798         spin_lock_irq(&efivars->lock);
 799
 800         /*
 801          * Ensure that the available space hasn't shrunk below the safe level
 802          */
 803
 804         status = check_var_size_locked(efivars, attributes, varsize);
 805
 806         if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
 807                 spin_unlock_irq(&efivars->lock);
 808                 kfree(data);
 809
 810                 return efi_status_to_err(status);
 811         }
 812
 813         status = efivars->ops->set_variable(var->var.VariableName,
 814                                             &var->var.VendorGuid,
 815                                             attributes, datasize,
 816                                             data);
 817
 818         if (status != EFI_SUCCESS) {
 819                 spin_unlock_irq(&efivars->lock);
 820                 kfree(data);
 821
 822                 return efi_status_to_err(status);
 823         }
 824
 825         bytes = count;
 826
 827         /*
 828          * Writing to the variable may have caused a change in size (which
 829          * could either be an append or an overwrite), or the variable to be
 830          * deleted. Perform a GetVariable() so we can tell what actually
 831          * happened.
 832          */
 833         newdatasize = 0;
 834         status = efivars->ops->get_variable(var->var.VariableName,
 835                                             &var->var.VendorGuid,
 836                                             NULL, &newdatasize,
 837                                             NULL);
 838
 839         if (status == EFI_BUFFER_TOO_SMALL) {
 840                 spin_unlock_irq(&efivars->lock);
 841                 mutex_lock(&inode->i_mutex);
 842                 i_size_write(inode, newdatasize + sizeof(attributes));
 843                 mutex_unlock(&inode->i_mutex);
 844
 845         } else if (status == EFI_NOT_FOUND) {
 846                 list_del(&var->list);
 847                 spin_unlock_irq(&efivars->lock);
 848                 efivar_unregister(var);
 849                 drop_nlink(inode);
 850                 d_delete(file->f_dentry);
 851                 dput(file->f_dentry);
 852
 853         } else {
 854                 spin_unlock_irq(&efivars->lock);
 855                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
 856                                 "status = %lx\n", status);
 857         }
 858
 859 out:
 860         kfree(data);
 861
 862         return bytes;
 863 }
 864
 865 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 866                 size_t count, loff_t *ppos)
 867 {
 868         struct efivar_entry *var = file->private_data;
 869         struct efivars *efivars = var->efivars;
 870         efi_status_t status;
 871         unsigned long datasize = 0;
 872         u32 attributes;
 873         void *data;
 874         ssize_t size = 0;
 875
 876         spin_lock_irq(&efivars->lock);
 877         status = efivars->ops->get_variable(var->var.VariableName,
 878                                             &var->var.VendorGuid,
 879                                             &attributes, &datasize, NULL);
 880         spin_unlock_irq(&efivars->lock);
 881
 882         if (status != EFI_BUFFER_TOO_SMALL)
 883                 return efi_status_to_err(status);
 884
 885         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 886
 887         if (!data)
 888                 return -ENOMEM;
 889
 890         spin_lock_irq(&efivars->lock);
 891         status = efivars->ops->get_variable(var->var.VariableName,
 892                                             &var->var.VendorGuid,
 893                                             &attributes, &datasize,
 894                                             (data + sizeof(attributes)));
 895         spin_unlock_irq(&efivars->lock);
 896
 897         if (status != EFI_SUCCESS) {
 898                 size = efi_status_to_err(status);
 899                 goto out_free;
 900         }
 901
 902         memcpy(data, &attributes, sizeof(attributes));
 903         size = simple_read_from_buffer(userbuf, count, ppos,
 904                                        data, datasize + sizeof(attributes));
 905 out_free:
 906         kfree(data);
 907
 908         return size;
 909 }
 910
 911 static void efivarfs_evict_inode(struct inode *inode)
 912 {
 913         clear_inode(inode);
 914 }
 915
 916 static const struct super_operations efivarfs_ops = {
 917         .statfs = simple_statfs,
 918         .drop_inode = generic_delete_inode,
 919         .evict_inode = efivarfs_evict_inode,
 920         .show_options = generic_show_options,
 921 };
 922
 923 static struct super_block *efivarfs_sb;
 924
 925 static const struct inode_operations efivarfs_dir_inode_operations;
 926
 927 static const struct file_operations efivarfs_file_operations = {
 928         .open   = efivarfs_file_open,
 929         .read   = efivarfs_file_read,
 930         .write  = efivarfs_file_write,
 931         .llseek = no_llseek,
 932 };
 933
 934 static struct inode *efivarfs_get_inode(struct super_block *sb,
 935                                 const struct inode *dir, int mode, dev_t dev)
 936 {
 937         struct inode *inode = new_inode(sb);
 938
 939         if (inode) {
 940                 inode->i_ino = get_next_ino();
 941                 inode->i_mode = mode;
 942                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 943                 switch (mode & S_IFMT) {
 944                 case S_IFREG:
 945                         inode->i_fop = &efivarfs_file_operations;
 946                         break;
 947                 case S_IFDIR:
 948                         inode->i_op = &efivarfs_dir_inode_operations;
 949                         inode->i_fop = &simple_dir_operations;
 950                         inc_nlink(inode);
 951                         break;
 952                 }
 953         }
 954         return inode;
 955 }
 956
 957 /*
 958  * Return true if 'str' is a valid efivarfs filename of the form,
 959  *
 960  *      VariableName-12345678-1234-1234-1234-1234567891bc
 961  */
 962 static bool efivarfs_valid_name(const char *str, int len)
 963 {
 964         static const char dashes[GUID_LEN] = {
 965                 [8] = 1, [13] = 1, [18] = 1, [23] = 1
 966         };
 967         const char *s = str + len - GUID_LEN;
 968         int i;
 969
 970         /*
 971          * We need a GUID, plus at least one letter for the variable name,
 972          * plus the '-' separator
 973          */
 974         if (len < GUID_LEN + 2)
 975                 return false;
 976
 977         /* GUID must be preceded by a '-' */
 978         if (*(s - 1) != '-')
 979                 return false;
 980
 981         /*
 982          * Validate that 's' is of the correct format, e.g.
 983          *
 984          *      12345678-1234-1234-1234-123456789abc
 985          */
 986         for (i = 0; i < GUID_LEN; i++) {
 987                 if (dashes[i]) {
 988                         if (*s++ != '-')
 989                                 return false;
 990                 } else {
 991                         if (!isxdigit(*s++))
 992                                 return false;
 993                 }
 994         }
 995
 996         return true;
 997 }
 998
 999 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
1000 {
1001         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
1002         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
1003         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
1004         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
1005         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
1006         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
1007         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
1008         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
1009         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
1010         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1011         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1012         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1013         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1014         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1015         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1016         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1017 }
1018
1019 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1020                           umode_t mode, bool excl)
1021 {
1022         struct inode *inode;
1023         struct efivars *efivars = &__efivars;
1024         struct efivar_entry *var;
1025         int namelen, i = 0, err = 0;
1026
1027         if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1028                 return -EINVAL;
1029
1030         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1031         if (!inode)
1032                 return -ENOMEM;
1033
1034         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1035         if (!var) {
1036                 err = -ENOMEM;
1037                 goto out;
1038         }
1039
1040         /* length of the variable name itself: remove GUID and separator */
1041         namelen = dentry->d_name.len - GUID_LEN - 1;
1042
1043         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1044                         &var->var.VendorGuid);
1045
1046         for (i = 0; i < namelen; i++)
1047                 var->var.VariableName[i] = dentry->d_name.name[i];
1048
1049         var->var.VariableName[i] = '\0';
1050
1051         inode->i_private = var;
1052         var->efivars = efivars;
1053         var->kobj.kset = efivars->kset;
1054
1055         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1056                              dentry->d_name.name);
1057         if (err)
1058                 goto out;
1059
1060         kobject_uevent(&var->kobj, KOBJ_ADD);
1061         spin_lock_irq(&efivars->lock);
1062         list_add(&var->list, &efivars->list);
1063         spin_unlock_irq(&efivars->lock);
1064         d_instantiate(dentry, inode);
1065         dget(dentry);
1066 out:
1067         if (err) {
1068                 kfree(var);
1069                 iput(inode);
1070         }
1071         return err;
1072 }
1073
1074 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1075 {
1076         struct efivar_entry *var = dentry->d_inode->i_private;
1077         struct efivars *efivars = var->efivars;
1078         efi_status_t status;
1079
1080         spin_lock_irq(&efivars->lock);
1081
1082         status = efivars->ops->set_variable(var->var.VariableName,
1083                                             &var->var.VendorGuid,
1084                                             0, 0, NULL);
1085
1086         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1087                 list_del(&var->list);
1088                 spin_unlock_irq(&efivars->lock);
1089                 efivar_unregister(var);
1090                 drop_nlink(dentry->d_inode);
1091                 dput(dentry);
1092                 return 0;
1093         }
1094
1095         spin_unlock_irq(&efivars->lock);
1096         return -EINVAL;
1097 };
1098
1099 /*
1100  * Compare two efivarfs file names.
1101  *
1102  * An efivarfs filename is composed of two parts,
1103  *
1104  *      1. A case-sensitive variable name
1105  *      2. A case-insensitive GUID
1106  *
1107  * So we need to perform a case-sensitive match on part 1 and a
1108  * case-insensitive match on part 2.
1109  */
1110 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1111                               const struct dentry *dentry, const struct inode *inode,
1112                               unsigned int len, const char *str,
1113                               const struct qstr *name)
1114 {
1115         int guid = len - GUID_LEN;
1116
1117         if (name->len != len)
1118                 return 1;
1119
1120         /* Case-sensitive compare for the variable name */
1121         if (memcmp(str, name->name, guid))
1122                 return 1;
1123
1124         /* Case-insensitive compare for the GUID */
1125         return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1126 }
1127
1128 static int efivarfs_d_hash(const struct dentry *dentry,
1129                            const struct inode *inode, struct qstr *qstr)
1130 {
1131         unsigned long hash = init_name_hash();
1132         const unsigned char *s = qstr->name;
1133         unsigned int len = qstr->len;
1134
1135         if (!efivarfs_valid_name(s, len))
1136                 return -EINVAL;
1137
1138         while (len-- > GUID_LEN)
1139                 hash = partial_name_hash(*s++, hash);
1140
1141         /* GUID is case-insensitive. */
1142         while (len--)
1143                 hash = partial_name_hash(tolower(*s++), hash);
1144
1145         qstr->hash = end_name_hash(hash);
1146         return 0;
1147 }
1148
1149 /*
1150  * Retaining negative dentries for an in-memory filesystem just wastes
1151  * memory and lookup time: arrange for them to be deleted immediately.
1152  */
1153 static int efivarfs_delete_dentry(const struct dentry *dentry)
1154 {
1155         return 1;
1156 }
1157
1158 static struct dentry_operations efivarfs_d_ops = {
1159         .d_compare = efivarfs_d_compare,
1160         .d_hash = efivarfs_d_hash,
1161         .d_delete = efivarfs_delete_dentry,
1162 };
1163
1164 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1165 {
1166         struct qstr q;
1167
1168         q.name = name;
1169         q.len = strlen(name);
1170
1171         if (efivarfs_d_hash(NULL, NULL, &q))
1172                 return NULL;
1173
1174         return d_alloc(parent, &q);
1175 }
1176
1177 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1178 {
1179         struct inode *inode = NULL;
1180         struct dentry *root;
1181         struct efivar_entry *entry, *n;
1182         struct efivars *efivars = &__efivars;
1183         char *name;
1184
1185         efivarfs_sb = sb;
1186
1187         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1188         sb->s_blocksize         = PAGE_CACHE_SIZE;
1189         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1190         sb->s_magic             = EFIVARFS_MAGIC;
1191         sb->s_op                = &efivarfs_ops;
1192         sb->s_d_op              = &efivarfs_d_ops;
1193         sb->s_time_gran         = 1;
1194
1195         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1196         if (!inode)
1197                 return -ENOMEM;
1198         inode->i_op = &efivarfs_dir_inode_operations;
1199
1200         root = d_make_root(inode);
1201         sb->s_root = root;
1202         if (!root)
1203                 return -ENOMEM;
1204
1205         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1206                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1207                 unsigned long size = 0;
1208                 int len, i;
1209
1210                 inode = NULL;
1211
1212                 len = utf16_strlen(entry->var.VariableName);
1213
1214                 /* name, plus '-', plus GUID, plus NUL*/
1215                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1216                 if (!name)
1217                         goto fail;
1218
1219                 for (i = 0; i < len; i++)
1220                         name[i] = entry->var.VariableName[i] & 0xFF;
1221
1222                 name[len] = '-';
1223
1224                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1225
1226                 name[len+GUID_LEN+1] = '\0';
1227
1228                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1229                                           S_IFREG | 0644, 0);
1230                 if (!inode)
1231                         goto fail_name;
1232
1233                 dentry = efivarfs_alloc_dentry(root, name);
1234                 if (!dentry)
1235                         goto fail_inode;
1236
1237                 /* copied by the above to local storage in the dentry. */
1238                 kfree(name);
1239
1240                 spin_lock_irq(&efivars->lock);
1241                 efivars->ops->get_variable(entry->var.VariableName,
1242                                            &entry->var.VendorGuid,
1243                                            &entry->var.Attributes,
1244                                            &size,
1245                                            NULL);
1246                 spin_unlock_irq(&efivars->lock);
1247
1248                 mutex_lock(&inode->i_mutex);
1249                 inode->i_private = entry;
1250                 i_size_write(inode, size + sizeof(entry->var.Attributes));
1251                 mutex_unlock(&inode->i_mutex);
1252                 d_add(dentry, inode);
1253         }
1254
1255         return 0;
1256
1257 fail_inode:
1258         iput(inode);
1259 fail_name:
1260         kfree(name);
1261 fail:
1262         return -ENOMEM;
1263 }
1264
1265 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1266                                     int flags, const char *dev_name, void *data)
1267 {
1268         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1269 }
1270
1271 static void efivarfs_kill_sb(struct super_block *sb)
1272 {
1273         kill_litter_super(sb);
1274         efivarfs_sb = NULL;
1275 }
1276
1277 static struct file_system_type efivarfs_type = {
1278         .name    = "efivarfs",
1279         .mount   = efivarfs_mount,
1280         .kill_sb = efivarfs_kill_sb,
1281 };
1282
1283 /*
1284  * Handle negative dentry.
1285  */
1286 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1287                                       unsigned int flags)
1288 {
1289         if (dentry->d_name.len > NAME_MAX)
1290                 return ERR_PTR(-ENAMETOOLONG);
1291         d_add(dentry, NULL);
1292         return NULL;
1293 }
1294
1295 static const struct inode_operations efivarfs_dir_inode_operations = {
1296         .lookup = efivarfs_lookup,
1297         .unlink = efivarfs_unlink,
1298         .create = efivarfs_create,
1299 };
1300
1301 static struct pstore_info efi_pstore_info;
1302
1303 #ifdef CONFIG_PSTORE
1304
1305 static int efi_pstore_open(struct pstore_info *psi)
1306 {
1307         struct efivars *efivars = psi->data;
1308
1309         spin_lock_irq(&efivars->lock);
1310         efivars->walk_entry = list_first_entry(&efivars->list,
1311                                                struct efivar_entry, list);
1312         return 0;
1313 }
1314
1315 static int efi_pstore_close(struct pstore_info *psi)
1316 {
1317         struct efivars *efivars = psi->data;
1318
1319         spin_unlock_irq(&efivars->lock);
1320         return 0;
1321 }
1322
1323 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1324                                int *count, struct timespec *timespec,
1325                                char **buf, struct pstore_info *psi)
1326 {
1327         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1328         struct efivars *efivars = psi->data;
1329         char name[DUMP_NAME_LEN];
1330         int i;
1331         int cnt;
1332         unsigned int part, size;
1333         unsigned long time;
1334
1335         while (&efivars->walk_entry->list != &efivars->list) {
1336                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1337                                  vendor)) {
1338                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1339                                 name[i] = efivars->walk_entry->var.VariableName[i];
1340                         }
1341                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1342                                    type, &part, &cnt, &time) == 4) {
1343                                 *id = part;
1344                                 *count = cnt;
1345                                 timespec->tv_sec = time;
1346                                 timespec->tv_nsec = 0;
1347                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1348                                    type, &part, &time) == 3) {
1349                                 /*
1350                                  * Check if an old format,
1351                                  * which doesn't support holding
1352                                  * multiple logs, remains.
1353                                  */
1354                                 *id = part;
1355                                 *count = 0;
1356                                 timespec->tv_sec = time;
1357                                 timespec->tv_nsec = 0;
1358                         } else {
1359                                 efivars->walk_entry = list_entry(
1360                                                 efivars->walk_entry->list.next,
1361                                                 struct efivar_entry, list);
1362                                 continue;
1363                         }
1364
1365                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1366                         size = efivars->walk_entry->var.DataSize;
1367                         *buf = kmalloc(size, GFP_KERNEL);
1368                         if (*buf == NULL)
1369                                 return -ENOMEM;
1370                         memcpy(*buf, efivars->walk_entry->var.Data,
1371                                size);
1372                         efivars->walk_entry = list_entry(
1373                                         efivars->walk_entry->list.next,
1374                                         struct efivar_entry, list);
1375                         return size;
1376                 }
1377                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1378                                                  struct efivar_entry, list);
1379         }
1380         return 0;
1381 }
1382
1383 static int efi_pstore_write(enum pstore_type_id type,
1384                 enum kmsg_dump_reason reason, u64 *id,
1385                 unsigned int part, int count, size_t size,
1386                 struct pstore_info *psi)
1387 {
1388         char name[DUMP_NAME_LEN];
1389         efi_char16_t efi_name[DUMP_NAME_LEN];
1390         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1391         struct efivars *efivars = psi->data;
1392         int i, ret = 0;
1393         efi_status_t status = EFI_NOT_FOUND;
1394         unsigned long flags;
1395
1396         if (pstore_cannot_block_path(reason)) {
1397                 /*
1398                  * If the lock is taken by another cpu in non-blocking path,
1399                  * this driver returns without entering firmware to avoid
1400                  * hanging up.
1401                  */
1402                 if (!spin_trylock_irqsave(&efivars->lock, flags))
1403                         return -EBUSY;
1404         } else
1405                 spin_lock_irqsave(&efivars->lock, flags);
1406
1407         /*
1408          * Check if there is a space enough to log.
1409          * size: a size of logging data
1410          * DUMP_NAME_LEN * 2: a maximum size of variable name
1411          */
1412
1413         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1414                                          size + DUMP_NAME_LEN * 2);
1415
1416         if (status) {
1417                 spin_unlock_irqrestore(&efivars->lock, flags);
1418                 *id = part;
1419                 return -ENOSPC;
1420         }
1421
1422         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1423                 get_seconds());
1424
1425         for (i = 0; i < DUMP_NAME_LEN; i++)
1426                 efi_name[i] = name[i];
1427
1428         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1429                                    size, psi->buf);
1430
1431         spin_unlock_irqrestore(&efivars->lock, flags);
1432
1433         if (reason == KMSG_DUMP_OOPS)
1434                 schedule_work(&efivar_work);
1435
1436         *id = part;
1437         return ret;
1438 };
1439
1440 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1441                             struct timespec time, struct pstore_info *psi)
1442 {
1443         char name[DUMP_NAME_LEN];
1444         efi_char16_t efi_name[DUMP_NAME_LEN];
1445         char name_old[DUMP_NAME_LEN];
1446         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1447         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1448         struct efivars *efivars = psi->data;
1449         struct efivar_entry *entry, *found = NULL;
1450         int i;
1451
1452         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1453                 time.tv_sec);
1454
1455         spin_lock_irq(&efivars->lock);
1456
1457         for (i = 0; i < DUMP_NAME_LEN; i++)
1458                 efi_name[i] = name[i];
1459
1460         /*
1461          * Clean up an entry with the same name
1462          */
1463
1464         list_for_each_entry(entry, &efivars->list, list) {
1465                 get_var_data_locked(efivars, &entry->var);
1466
1467                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1468                         continue;
1469                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1470                                   utf16_strlen(efi_name))) {
1471                         /*
1472                          * Check if an old format,
1473                          * which doesn't support holding
1474                          * multiple logs, remains.
1475                          */
1476                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1477                                 (unsigned int)id, time.tv_sec);
1478
1479                         for (i = 0; i < DUMP_NAME_LEN; i++)
1480                                 efi_name_old[i] = name_old[i];
1481
1482                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1483                                           utf16_strlen(efi_name_old)))
1484                                 continue;
1485                 }
1486
1487                 /* found */
1488                 found = entry;
1489                 efivars->ops->set_variable(entry->var.VariableName,
1490                                            &entry->var.VendorGuid,
1491                                            PSTORE_EFI_ATTRIBUTES,
1492                                            0, NULL);
1493                 break;
1494         }
1495
1496         if (found)
1497                 list_del(&found->list);
1498
1499         spin_unlock_irq(&efivars->lock);
1500
1501         if (found)
1502                 efivar_unregister(found);
1503
1504         return 0;
1505 }
1506 #else
1507 static int efi_pstore_open(struct pstore_info *psi)
1508 {
1509         return 0;
1510 }
1511
1512 static int efi_pstore_close(struct pstore_info *psi)
1513 {
1514         return 0;
1515 }
1516
1517 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1518                                struct timespec *timespec,
1519                                char **buf, struct pstore_info *psi)
1520 {
1521         return -1;
1522 }
1523
1524 static int efi_pstore_write(enum pstore_type_id type,
1525                 enum kmsg_dump_reason reason, u64 *id,
1526                 unsigned int part, int count, size_t size,
1527                 struct pstore_info *psi)
1528 {
1529         return 0;
1530 }
1531
1532 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1533                             struct timespec time, struct pstore_info *psi)
1534 {
1535         return 0;
1536 }
1537 #endif
1538
1539 static struct pstore_info efi_pstore_info = {
1540         .owner          = THIS_MODULE,
1541         .name           = "efi",
1542         .open           = efi_pstore_open,
1543         .close          = efi_pstore_close,
1544         .read           = efi_pstore_read,
1545         .write          = efi_pstore_write,
1546         .erase          = efi_pstore_erase,
1547 };
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         efivars->efi_pstore_info = efi_pstore_info;
2018
2019         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
2020         if (efivars->efi_pstore_info.buf) {
2021                 efivars->efi_pstore_info.bufsize = 1024;
2022                 efivars->efi_pstore_info.data = efivars;
2023                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
2024                 pstore_register(&efivars->efi_pstore_info);
2025         }
2026
2027         register_filesystem(&efivarfs_type);
2028
2029 out:
2030         kfree(variable_name);
2031
2032         return error;
2033 }
2034 EXPORT_SYMBOL_GPL(register_efivars);
2035
2036 /*
2037  * For now we register the efi subsystem with the firmware subsystem
2038  * and the vars subsystem with the efi subsystem.  In the future, it
2039  * might make sense to split off the efi subsystem into its own
2040  * driver, but for now only efivars will register with it, so just
2041  * include it here.
2042  */
2043
2044 static int __init
2045 efivars_init(void)
2046 {
2047         int error = 0;
2048
2049         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2050                EFIVARS_DATE);
2051
2052         if (!efi_enabled(EFI_RUNTIME_SERVICES))
2053                 return 0;
2054
2055         /* For now we'll register the efi directory at /sys/firmware/efi */
2056         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2057         if (!efi_kobj) {
2058                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2059                 return -ENOMEM;
2060         }
2061
2062         ops.get_variable = efi.get_variable;
2063         ops.set_variable = efi.set_variable;
2064         ops.get_next_variable = efi.get_next_variable;
2065         ops.query_variable_info = efi.query_variable_info;
2066
2067         error = register_efivars(&__efivars, &ops, efi_kobj);
2068         if (error)
2069                 goto err_put;
2070
2071         /* Don't forget the systab entry */
2072         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2073         if (error) {
2074                 printk(KERN_ERR
2075                        "efivars: Sysfs attribute export failed with error %d.\n",
2076                        error);
2077                 goto err_unregister;
2078         }
2079
2080         return 0;
2081
2082 err_unregister:
2083         unregister_efivars(&__efivars);
2084 err_put:
2085         kobject_put(efi_kobj);
2086         return error;
2087 }
2088
2089 static void __exit
2090 efivars_exit(void)
2091 {
2092         cancel_work_sync(&efivar_work);
2093
2094         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2095                 unregister_efivars(&__efivars);
2096                 kobject_put(efi_kobj);
2097         }
2098 }
2099
2100 module_init(efivars_init);
2101 module_exit(efivars_exit);
2102