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 static bool efivar_wq_enabled = true;
 174
 175 /* Return the number of unicode characters in data */
 176 static unsigned long
 177 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 178 {
 179         unsigned long length = 0;
 180
 181         while (*s++ != 0 && length < maxlength)
 182                 length++;
 183         return length;
 184 }
 185
 186 static inline unsigned long
 187 utf16_strlen(efi_char16_t *s)
 188 {
 189         return utf16_strnlen(s, ~0UL);
 190 }
 191
 192 /*
 193  * Return the number of bytes is the length of this string
 194  * Note: this is NOT the same as the number of unicode characters
 195  */
 196 static inline unsigned long
 197 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 198 {
 199         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 200 }
 201
 202 static inline int
 203 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 204 {
 205         while (1) {
 206                 if (len == 0)
 207                         return 0;
 208                 if (*a < *b)
 209                         return -1;
 210                 if (*a > *b)
 211                         return 1;
 212                 if (*a == 0) /* implies *b == 0 */
 213                         return 0;
 214                 a++;
 215                 b++;
 216                 len--;
 217         }
 218 }
 219
 220 static bool
 221 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 222                      unsigned long len)
 223 {
 224         struct efi_generic_dev_path *node;
 225         int offset = 0;
 226
 227         node = (struct efi_generic_dev_path *)buffer;
 228
 229         if (len < sizeof(*node))
 230                 return false;
 231
 232         while (offset <= len - sizeof(*node) &&
 233                node->length >= sizeof(*node) &&
 234                 node->length <= len - offset) {
 235                 offset += node->length;
 236
 237                 if ((node->type == EFI_DEV_END_PATH ||
 238                      node->type == EFI_DEV_END_PATH2) &&
 239                     node->sub_type == EFI_DEV_END_ENTIRE)
 240                         return true;
 241
 242                 node = (struct efi_generic_dev_path *)(buffer + offset);
 243         }
 244
 245         /*
 246          * If we're here then either node->length pointed past the end
 247          * of the buffer or we reached the end of the buffer without
 248          * finding a device path end node.
 249          */
 250         return false;
 251 }
 252
 253 static bool
 254 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 255                     unsigned long len)
 256 {
 257         /* An array of 16-bit integers */
 258         if ((len % 2) != 0)
 259                 return false;
 260
 261         return true;
 262 }
 263
 264 static bool
 265 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 266                      unsigned long len)
 267 {
 268         u16 filepathlength;
 269         int i, desclength = 0, namelen;
 270
 271         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 272
 273         /* Either "Boot" or "Driver" followed by four digits of hex */
 274         for (i = match; i < match+4; i++) {
 275                 if (var->VariableName[i] > 127 ||
 276                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 277                         return true;
 278         }
 279
 280         /* Reject it if there's 4 digits of hex and then further content */
 281         if (namelen > match + 4)
 282                 return false;
 283
 284         /* A valid entry must be at least 8 bytes */
 285         if (len < 8)
 286                 return false;
 287
 288         filepathlength = buffer[4] | buffer[5] << 8;
 289
 290         /*
 291          * There's no stored length for the description, so it has to be
 292          * found by hand
 293          */
 294         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 295
 296         /* Each boot entry must have a descriptor */
 297         if (!desclength)
 298                 return false;
 299
 300         /*
 301          * If the sum of the length of the description, the claimed filepath
 302          * length and the original header are greater than the length of the
 303          * variable, it's malformed
 304          */
 305         if ((desclength + filepathlength + 6) > len)
 306                 return false;
 307
 308         /*
 309          * And, finally, check the filepath
 310          */
 311         return validate_device_path(var, match, buffer + desclength + 6,
 312                                     filepathlength);
 313 }
 314
 315 static bool
 316 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 317                 unsigned long len)
 318 {
 319         /* A single 16-bit integer */
 320         if (len != 2)
 321                 return false;
 322
 323         return true;
 324 }
 325
 326 static bool
 327 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 328                       unsigned long len)
 329 {
 330         int i;
 331
 332         for (i = 0; i < len; i++) {
 333                 if (buffer[i] > 127)
 334                         return false;
 335
 336                 if (buffer[i] == 0)
 337                         return true;
 338         }
 339
 340         return false;
 341 }
 342
 343 struct variable_validate {
 344         char *name;
 345         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 346                          unsigned long len);
 347 };
 348
 349 static const struct variable_validate variable_validate[] = {
 350         { "BootNext", validate_uint16 },
 351         { "BootOrder", validate_boot_order },
 352         { "DriverOrder", validate_boot_order },
 353         { "Boot*", validate_load_option },
 354         { "Driver*", validate_load_option },
 355         { "ConIn", validate_device_path },
 356         { "ConInDev", validate_device_path },
 357         { "ConOut", validate_device_path },
 358         { "ConOutDev", validate_device_path },
 359         { "ErrOut", validate_device_path },
 360         { "ErrOutDev", validate_device_path },
 361         { "Timeout", validate_uint16 },
 362         { "Lang", validate_ascii_string },
 363         { "PlatformLang", validate_ascii_string },
 364         { "", NULL },
 365 };
 366
 367 static bool
 368 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 369 {
 370         int i;
 371         u16 *unicode_name = var->VariableName;
 372
 373         for (i = 0; variable_validate[i].validate != NULL; i++) {
 374                 const char *name = variable_validate[i].name;
 375                 int match;
 376
 377                 for (match = 0; ; match++) {
 378                         char c = name[match];
 379                         u16 u = unicode_name[match];
 380
 381                         /* All special variables are plain ascii */
 382                         if (u > 127)
 383                                 return true;
 384
 385                         /* Wildcard in the matching name means we've matched */
 386                         if (c == '*')
 387                                 return variable_validate[i].validate(var,
 388                                                              match, data, len);
 389
 390                         /* Case sensitive match */
 391                         if (c != u)
 392                                 break;
 393
 394                         /* Reached the end of the string while matching */
 395                         if (!c)
 396                                 return variable_validate[i].validate(var,
 397                                                              match, data, len);
 398                 }
 399         }
 400
 401         return true;
 402 }
 403
 404 static efi_status_t
 405 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 406 {
 407         efi_status_t status;
 408
 409         var->DataSize = 1024;
 410         status = efivars->ops->get_variable(var->VariableName,
 411                                             &var->VendorGuid,
 412                                             &var->Attributes,
 413                                             &var->DataSize,
 414                                             var->Data);
 415         return status;
 416 }
 417
 418 static efi_status_t
 419 get_var_data(struct efivars *efivars, struct efi_variable *var)
 420 {
 421         efi_status_t status;
 422         unsigned long flags;
 423
 424         spin_lock_irqsave(&efivars->lock, flags);
 425         status = get_var_data_locked(efivars, var);
 426         spin_unlock_irqrestore(&efivars->lock, flags);
 427
 428         if (status != EFI_SUCCESS) {
 429                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 430                         status);
 431         }
 432         return status;
 433 }
 434
 435 static efi_status_t
 436 check_var_size_locked(struct efivars *efivars, u32 attributes,
 437                         unsigned long size)
 438 {
 439         u64 storage_size, remaining_size, max_size;
 440         efi_status_t status;
 441         const struct efivar_operations *fops = efivars->ops;
 442
 443         if (!efivars->ops->query_variable_info)
 444                 return EFI_UNSUPPORTED;
 445
 446         status = fops->query_variable_info(attributes, &storage_size,
 447                                            &remaining_size, &max_size);
 448
 449         if (status != EFI_SUCCESS)
 450                 return status;
 451
 452         if (!storage_size || size > remaining_size || size > max_size ||
 453             (remaining_size - size) < (storage_size / 2))
 454                 return EFI_OUT_OF_RESOURCES;
 455
 456         return status;
 457 }
 458
 459
 460 static efi_status_t
 461 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
 462 {
 463         efi_status_t status;
 464         unsigned long flags;
 465
 466         spin_lock_irqsave(&efivars->lock, flags);
 467         status = check_var_size_locked(efivars, attributes, size);
 468         spin_unlock_irqrestore(&efivars->lock, flags);
 469
 470         return status;
 471 }
 472
 473 static ssize_t
 474 efivar_guid_read(struct efivar_entry *entry, char *buf)
 475 {
 476         struct efi_variable *var = &entry->var;
 477         char *str = buf;
 478
 479         if (!entry || !buf)
 480                 return 0;
 481
 482         efi_guid_unparse(&var->VendorGuid, str);
 483         str += strlen(str);
 484         str += sprintf(str, "\n");
 485
 486         return str - buf;
 487 }
 488
 489 static ssize_t
 490 efivar_attr_read(struct efivar_entry *entry, char *buf)
 491 {
 492         struct efi_variable *var = &entry->var;
 493         char *str = buf;
 494         efi_status_t status;
 495
 496         if (!entry || !buf)
 497                 return -EINVAL;
 498
 499         status = get_var_data(entry->efivars, var);
 500         if (status != EFI_SUCCESS)
 501                 return -EIO;
 502
 503         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 504                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 505         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 506                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 507         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 508                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 509         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 510                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 511         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 512                 str += sprintf(str,
 513                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 514         if (var->Attributes &
 515                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 516                 str += sprintf(str,
 517                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 518         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 519                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 520         return str - buf;
 521 }
 522
 523 static ssize_t
 524 efivar_size_read(struct efivar_entry *entry, char *buf)
 525 {
 526         struct efi_variable *var = &entry->var;
 527         char *str = buf;
 528         efi_status_t status;
 529
 530         if (!entry || !buf)
 531                 return -EINVAL;
 532
 533         status = get_var_data(entry->efivars, var);
 534         if (status != EFI_SUCCESS)
 535                 return -EIO;
 536
 537         str += sprintf(str, "0x%lx\n", var->DataSize);
 538         return str - buf;
 539 }
 540
 541 static ssize_t
 542 efivar_data_read(struct efivar_entry *entry, char *buf)
 543 {
 544         struct efi_variable *var = &entry->var;
 545         efi_status_t status;
 546
 547         if (!entry || !buf)
 548                 return -EINVAL;
 549
 550         status = get_var_data(entry->efivars, var);
 551         if (status != EFI_SUCCESS)
 552                 return -EIO;
 553
 554         memcpy(buf, var->Data, var->DataSize);
 555         return var->DataSize;
 556 }
 557 /*
 558  * We allow each variable to be edited via rewriting the
 559  * entire efi variable structure.
 560  */
 561 static ssize_t
 562 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 563 {
 564         struct efi_variable *new_var, *var = &entry->var;
 565         struct efivars *efivars = entry->efivars;
 566         efi_status_t status = EFI_NOT_FOUND;
 567
 568         if (count != sizeof(struct efi_variable))
 569                 return -EINVAL;
 570
 571         new_var = (struct efi_variable *)buf;
 572         /*
 573          * If only updating the variable data, then the name
 574          * and guid should remain the same
 575          */
 576         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 577                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 578                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 579                 return -EINVAL;
 580         }
 581
 582         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 583                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 584                 return -EINVAL;
 585         }
 586
 587         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 588             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 589                 printk(KERN_ERR "efivars: Malformed variable content\n");
 590                 return -EINVAL;
 591         }
 592
 593         spin_lock_irq(&efivars->lock);
 594
 595         status = check_var_size_locked(efivars, new_var->Attributes,
 596                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 597
 598         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 599                 status = efivars->ops->set_variable(new_var->VariableName,
 600                                                     &new_var->VendorGuid,
 601                                                     new_var->Attributes,
 602                                                     new_var->DataSize,
 603                                                     new_var->Data);
 604
 605         spin_unlock_irq(&efivars->lock);
 606
 607         if (status != EFI_SUCCESS) {
 608                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 609                         status);
 610                 return -EIO;
 611         }
 612
 613         memcpy(&entry->var, new_var, count);
 614         return count;
 615 }
 616
 617 static ssize_t
 618 efivar_show_raw(struct efivar_entry *entry, char *buf)
 619 {
 620         struct efi_variable *var = &entry->var;
 621         efi_status_t status;
 622
 623         if (!entry || !buf)
 624                 return 0;
 625
 626         status = get_var_data(entry->efivars, var);
 627         if (status != EFI_SUCCESS)
 628                 return -EIO;
 629
 630         memcpy(buf, var, sizeof(*var));
 631         return sizeof(*var);
 632 }
 633
 634 /*
 635  * Generic read/write functions that call the specific functions of
 636  * the attributes...
 637  */
 638 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 639                                 char *buf)
 640 {
 641         struct efivar_entry *var = to_efivar_entry(kobj);
 642         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 643         ssize_t ret = -EIO;
 644
 645         if (!capable(CAP_SYS_ADMIN))
 646                 return -EACCES;
 647
 648         if (efivar_attr->show) {
 649                 ret = efivar_attr->show(var, buf);
 650         }
 651         return ret;
 652 }
 653
 654 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 655                                 const char *buf, size_t count)
 656 {
 657         struct efivar_entry *var = to_efivar_entry(kobj);
 658         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 659         ssize_t ret = -EIO;
 660
 661         if (!capable(CAP_SYS_ADMIN))
 662                 return -EACCES;
 663
 664         if (efivar_attr->store)
 665                 ret = efivar_attr->store(var, buf, count);
 666
 667         return ret;
 668 }
 669
 670 static const struct sysfs_ops efivar_attr_ops = {
 671         .show = efivar_attr_show,
 672         .store = efivar_attr_store,
 673 };
 674
 675 static void efivar_release(struct kobject *kobj)
 676 {
 677         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 678         kfree(var);
 679 }
 680
 681 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 682 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 683 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 684 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 685 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 686
 687 static struct attribute *def_attrs[] = {
 688         &efivar_attr_guid.attr,
 689         &efivar_attr_size.attr,
 690         &efivar_attr_attributes.attr,
 691         &efivar_attr_data.attr,
 692         &efivar_attr_raw_var.attr,
 693         NULL,
 694 };
 695
 696 static struct kobj_type efivar_ktype = {
 697         .release = efivar_release,
 698         .sysfs_ops = &efivar_attr_ops,
 699         .default_attrs = def_attrs,
 700 };
 701
 702 static inline void
 703 efivar_unregister(struct efivar_entry *var)
 704 {
 705         kobject_put(&var->kobj);
 706 }
 707
 708 static int efivarfs_file_open(struct inode *inode, struct file *file)
 709 {
 710         file->private_data = inode->i_private;
 711         return 0;
 712 }
 713
 714 static int efi_status_to_err(efi_status_t status)
 715 {
 716         int err;
 717
 718         switch (status) {
 719         case EFI_INVALID_PARAMETER:
 720                 err = -EINVAL;
 721                 break;
 722         case EFI_OUT_OF_RESOURCES:
 723                 err = -ENOSPC;
 724                 break;
 725         case EFI_DEVICE_ERROR:
 726                 err = -EIO;
 727                 break;
 728         case EFI_WRITE_PROTECTED:
 729                 err = -EROFS;
 730                 break;
 731         case EFI_SECURITY_VIOLATION:
 732                 err = -EACCES;
 733                 break;
 734         case EFI_NOT_FOUND:
 735                 err = -EIO;
 736                 break;
 737         default:
 738                 err = -EINVAL;
 739         }
 740
 741         return err;
 742 }
 743
 744 static ssize_t efivarfs_file_write(struct file *file,
 745                 const char __user *userbuf, size_t count, loff_t *ppos)
 746 {
 747         struct efivar_entry *var = file->private_data;
 748         struct efivars *efivars;
 749         efi_status_t status;
 750         void *data;
 751         u32 attributes;
 752         struct inode *inode = file->f_mapping->host;
 753         unsigned long datasize = count - sizeof(attributes);
 754         unsigned long newdatasize, varsize;
 755         ssize_t bytes = 0;
 756
 757         if (count < sizeof(attributes))
 758                 return -EINVAL;
 759
 760         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 761                 return -EFAULT;
 762
 763         if (attributes & ~(EFI_VARIABLE_MASK))
 764                 return -EINVAL;
 765
 766         efivars = var->efivars;
 767
 768         /*
 769          * Ensure that the user can't allocate arbitrarily large
 770          * amounts of memory. Pick a default size of 64K if
 771          * QueryVariableInfo() isn't supported by the firmware.
 772          */
 773
 774         varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
 775         status = check_var_size(efivars, attributes, varsize);
 776
 777         if (status != EFI_SUCCESS) {
 778                 if (status != EFI_UNSUPPORTED)
 779                         return efi_status_to_err(status);
 780
 781                 if (datasize > 65536)
 782                         return -ENOSPC;
 783         }
 784
 785         data = kmalloc(datasize, GFP_KERNEL);
 786         if (!data)
 787                 return -ENOMEM;
 788
 789         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 790                 bytes = -EFAULT;
 791                 goto out;
 792         }
 793
 794         if (validate_var(&var->var, data, datasize) == false) {
 795                 bytes = -EINVAL;
 796                 goto out;
 797         }
 798
 799         /*
 800          * The lock here protects the get_variable call, the conditional
 801          * set_variable call, and removal of the variable from the efivars
 802          * list (in the case of an authenticated delete).
 803          */
 804         spin_lock_irq(&efivars->lock);
 805
 806         /*
 807          * Ensure that the available space hasn't shrunk below the safe level
 808          */
 809
 810         status = check_var_size_locked(efivars, attributes, varsize);
 811
 812         if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
 813                 spin_unlock_irq(&efivars->lock);
 814                 kfree(data);
 815
 816                 return efi_status_to_err(status);
 817         }
 818
 819         status = efivars->ops->set_variable(var->var.VariableName,
 820                                             &var->var.VendorGuid,
 821                                             attributes, datasize,
 822                                             data);
 823
 824         if (status != EFI_SUCCESS) {
 825                 spin_unlock_irq(&efivars->lock);
 826                 kfree(data);
 827
 828                 return efi_status_to_err(status);
 829         }
 830
 831         bytes = count;
 832
 833         /*
 834          * Writing to the variable may have caused a change in size (which
 835          * could either be an append or an overwrite), or the variable to be
 836          * deleted. Perform a GetVariable() so we can tell what actually
 837          * happened.
 838          */
 839         newdatasize = 0;
 840         status = efivars->ops->get_variable(var->var.VariableName,
 841                                             &var->var.VendorGuid,
 842                                             NULL, &newdatasize,
 843                                             NULL);
 844
 845         if (status == EFI_BUFFER_TOO_SMALL) {
 846                 spin_unlock_irq(&efivars->lock);
 847                 mutex_lock(&inode->i_mutex);
 848                 i_size_write(inode, newdatasize + sizeof(attributes));
 849                 mutex_unlock(&inode->i_mutex);
 850
 851         } else if (status == EFI_NOT_FOUND) {
 852                 list_del(&var->list);
 853                 spin_unlock_irq(&efivars->lock);
 854                 efivar_unregister(var);
 855                 drop_nlink(inode);
 856                 d_delete(file->f_dentry);
 857                 dput(file->f_dentry);
 858
 859         } else {
 860                 spin_unlock_irq(&efivars->lock);
 861                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
 862                                 "status = %lx\n", status);
 863         }
 864
 865 out:
 866         kfree(data);
 867
 868         return bytes;
 869 }
 870
 871 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 872                 size_t count, loff_t *ppos)
 873 {
 874         struct efivar_entry *var = file->private_data;
 875         struct efivars *efivars = var->efivars;
 876         efi_status_t status;
 877         unsigned long datasize = 0;
 878         u32 attributes;
 879         void *data;
 880         ssize_t size = 0;
 881
 882         spin_lock_irq(&efivars->lock);
 883         status = efivars->ops->get_variable(var->var.VariableName,
 884                                             &var->var.VendorGuid,
 885                                             &attributes, &datasize, NULL);
 886         spin_unlock_irq(&efivars->lock);
 887
 888         if (status != EFI_BUFFER_TOO_SMALL)
 889                 return efi_status_to_err(status);
 890
 891         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 892
 893         if (!data)
 894                 return -ENOMEM;
 895
 896         spin_lock_irq(&efivars->lock);
 897         status = efivars->ops->get_variable(var->var.VariableName,
 898                                             &var->var.VendorGuid,
 899                                             &attributes, &datasize,
 900                                             (data + sizeof(attributes)));
 901         spin_unlock_irq(&efivars->lock);
 902
 903         if (status != EFI_SUCCESS) {
 904                 size = efi_status_to_err(status);
 905                 goto out_free;
 906         }
 907
 908         memcpy(data, &attributes, sizeof(attributes));
 909         size = simple_read_from_buffer(userbuf, count, ppos,
 910                                        data, datasize + sizeof(attributes));
 911 out_free:
 912         kfree(data);
 913
 914         return size;
 915 }
 916
 917 static void efivarfs_evict_inode(struct inode *inode)
 918 {
 919         clear_inode(inode);
 920 }
 921
 922 static const struct super_operations efivarfs_ops = {
 923         .statfs = simple_statfs,
 924         .drop_inode = generic_delete_inode,
 925         .evict_inode = efivarfs_evict_inode,
 926         .show_options = generic_show_options,
 927 };
 928
 929 static struct super_block *efivarfs_sb;
 930
 931 static const struct inode_operations efivarfs_dir_inode_operations;
 932
 933 static const struct file_operations efivarfs_file_operations = {
 934         .open   = efivarfs_file_open,
 935         .read   = efivarfs_file_read,
 936         .write  = efivarfs_file_write,
 937         .llseek = no_llseek,
 938 };
 939
 940 static struct inode *efivarfs_get_inode(struct super_block *sb,
 941                                 const struct inode *dir, int mode, dev_t dev)
 942 {
 943         struct inode *inode = new_inode(sb);
 944
 945         if (inode) {
 946                 inode->i_ino = get_next_ino();
 947                 inode->i_mode = mode;
 948                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 949                 switch (mode & S_IFMT) {
 950                 case S_IFREG:
 951                         inode->i_fop = &efivarfs_file_operations;
 952                         break;
 953                 case S_IFDIR:
 954                         inode->i_op = &efivarfs_dir_inode_operations;
 955                         inode->i_fop = &simple_dir_operations;
 956                         inc_nlink(inode);
 957                         break;
 958                 }
 959         }
 960         return inode;
 961 }
 962
 963 /*
 964  * Return true if 'str' is a valid efivarfs filename of the form,
 965  *
 966  *      VariableName-12345678-1234-1234-1234-1234567891bc
 967  */
 968 static bool efivarfs_valid_name(const char *str, int len)
 969 {
 970         static const char dashes[GUID_LEN] = {
 971                 [8] = 1, [13] = 1, [18] = 1, [23] = 1
 972         };
 973         const char *s = str + len - GUID_LEN;
 974         int i;
 975
 976         /*
 977          * We need a GUID, plus at least one letter for the variable name,
 978          * plus the '-' separator
 979          */
 980         if (len < GUID_LEN + 2)
 981                 return false;
 982
 983         /* GUID must be preceded by a '-' */
 984         if (*(s - 1) != '-')
 985                 return false;
 986
 987         /*
 988          * Validate that 's' is of the correct format, e.g.
 989          *
 990          *      12345678-1234-1234-1234-123456789abc
 991          */
 992         for (i = 0; i < GUID_LEN; i++) {
 993                 if (dashes[i]) {
 994                         if (*s++ != '-')
 995                                 return false;
 996                 } else {
 997                         if (!isxdigit(*s++))
 998                                 return false;
 999                 }
1000         }
1001
1002         return true;
1003 }
1004
1005 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
1006 {
1007         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
1008         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
1009         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
1010         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
1011         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
1012         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
1013         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
1014         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
1015         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
1016         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1017         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1018         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1019         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1020         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1021         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1022         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1023 }
1024
1025 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1026                           umode_t mode, bool excl)
1027 {
1028         struct inode *inode;
1029         struct efivars *efivars = &__efivars;
1030         struct efivar_entry *var;
1031         int namelen, i = 0, err = 0;
1032
1033         if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1034                 return -EINVAL;
1035
1036         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1037         if (!inode)
1038                 return -ENOMEM;
1039
1040         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1041         if (!var) {
1042                 err = -ENOMEM;
1043                 goto out;
1044         }
1045
1046         /* length of the variable name itself: remove GUID and separator */
1047         namelen = dentry->d_name.len - GUID_LEN - 1;
1048
1049         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1050                         &var->var.VendorGuid);
1051
1052         for (i = 0; i < namelen; i++)
1053                 var->var.VariableName[i] = dentry->d_name.name[i];
1054
1055         var->var.VariableName[i] = '\0';
1056
1057         inode->i_private = var;
1058         var->efivars = efivars;
1059         var->kobj.kset = efivars->kset;
1060
1061         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1062                              dentry->d_name.name);
1063         if (err)
1064                 goto out;
1065
1066         kobject_uevent(&var->kobj, KOBJ_ADD);
1067         spin_lock_irq(&efivars->lock);
1068         list_add(&var->list, &efivars->list);
1069         spin_unlock_irq(&efivars->lock);
1070         d_instantiate(dentry, inode);
1071         dget(dentry);
1072 out:
1073         if (err) {
1074                 kfree(var);
1075                 iput(inode);
1076         }
1077         return err;
1078 }
1079
1080 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1081 {
1082         struct efivar_entry *var = dentry->d_inode->i_private;
1083         struct efivars *efivars = var->efivars;
1084         efi_status_t status;
1085
1086         spin_lock_irq(&efivars->lock);
1087
1088         status = efivars->ops->set_variable(var->var.VariableName,
1089                                             &var->var.VendorGuid,
1090                                             0, 0, NULL);
1091
1092         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1093                 list_del(&var->list);
1094                 spin_unlock_irq(&efivars->lock);
1095                 efivar_unregister(var);
1096                 drop_nlink(dentry->d_inode);
1097                 dput(dentry);
1098                 return 0;
1099         }
1100
1101         spin_unlock_irq(&efivars->lock);
1102         return -EINVAL;
1103 };
1104
1105 /*
1106  * Compare two efivarfs file names.
1107  *
1108  * An efivarfs filename is composed of two parts,
1109  *
1110  *      1. A case-sensitive variable name
1111  *      2. A case-insensitive GUID
1112  *
1113  * So we need to perform a case-sensitive match on part 1 and a
1114  * case-insensitive match on part 2.
1115  */
1116 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1117                               const struct dentry *dentry, const struct inode *inode,
1118                               unsigned int len, const char *str,
1119                               const struct qstr *name)
1120 {
1121         int guid = len - GUID_LEN;
1122
1123         if (name->len != len)
1124                 return 1;
1125
1126         /* Case-sensitive compare for the variable name */
1127         if (memcmp(str, name->name, guid))
1128                 return 1;
1129
1130         /* Case-insensitive compare for the GUID */
1131         return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1132 }
1133
1134 static int efivarfs_d_hash(const struct dentry *dentry,
1135                            const struct inode *inode, struct qstr *qstr)
1136 {
1137         unsigned long hash = init_name_hash();
1138         const unsigned char *s = qstr->name;
1139         unsigned int len = qstr->len;
1140
1141         if (!efivarfs_valid_name(s, len))
1142                 return -EINVAL;
1143
1144         while (len-- > GUID_LEN)
1145                 hash = partial_name_hash(*s++, hash);
1146
1147         /* GUID is case-insensitive. */
1148         while (len--)
1149                 hash = partial_name_hash(tolower(*s++), hash);
1150
1151         qstr->hash = end_name_hash(hash);
1152         return 0;
1153 }
1154
1155 /*
1156  * Retaining negative dentries for an in-memory filesystem just wastes
1157  * memory and lookup time: arrange for them to be deleted immediately.
1158  */
1159 static int efivarfs_delete_dentry(const struct dentry *dentry)
1160 {
1161         return 1;
1162 }
1163
1164 static struct dentry_operations efivarfs_d_ops = {
1165         .d_compare = efivarfs_d_compare,
1166         .d_hash = efivarfs_d_hash,
1167         .d_delete = efivarfs_delete_dentry,
1168 };
1169
1170 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1171 {
1172         struct dentry *d;
1173         struct qstr q;
1174         int err;
1175
1176         q.name = name;
1177         q.len = strlen(name);
1178
1179         err = efivarfs_d_hash(NULL, NULL, &q);
1180         if (err)
1181                 return ERR_PTR(err);
1182
1183         d = d_alloc(parent, &q);
1184         if (d)
1185                 return d;
1186
1187         return ERR_PTR(-ENOMEM);
1188 }
1189
1190 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1191 {
1192         struct inode *inode = NULL;
1193         struct dentry *root;
1194         struct efivar_entry *entry, *n;
1195         struct efivars *efivars = &__efivars;
1196         char *name;
1197         int err = -ENOMEM;
1198
1199         efivarfs_sb = sb;
1200
1201         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1202         sb->s_blocksize         = PAGE_CACHE_SIZE;
1203         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1204         sb->s_magic             = EFIVARFS_MAGIC;
1205         sb->s_op                = &efivarfs_ops;
1206         sb->s_d_op              = &efivarfs_d_ops;
1207         sb->s_time_gran         = 1;
1208
1209         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1210         if (!inode)
1211                 return -ENOMEM;
1212         inode->i_op = &efivarfs_dir_inode_operations;
1213
1214         root = d_make_root(inode);
1215         sb->s_root = root;
1216         if (!root)
1217                 return -ENOMEM;
1218
1219         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1220                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1221                 unsigned long size = 0;
1222                 int len, i;
1223
1224                 inode = NULL;
1225
1226                 len = utf16_strlen(entry->var.VariableName);
1227
1228                 /* name, plus '-', plus GUID, plus NUL*/
1229                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1230                 if (!name)
1231                         goto fail;
1232
1233                 for (i = 0; i < len; i++)
1234                         name[i] = entry->var.VariableName[i] & 0xFF;
1235
1236                 name[len] = '-';
1237
1238                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1239
1240                 name[len+GUID_LEN+1] = '\0';
1241
1242                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1243                                           S_IFREG | 0644, 0);
1244                 if (!inode)
1245                         goto fail_name;
1246
1247                 dentry = efivarfs_alloc_dentry(root, name);
1248                 if (IS_ERR(dentry)) {
1249                         err = PTR_ERR(dentry);
1250                         goto fail_inode;
1251                 }
1252
1253                 /* copied by the above to local storage in the dentry. */
1254                 kfree(name);
1255
1256                 spin_lock_irq(&efivars->lock);
1257                 efivars->ops->get_variable(entry->var.VariableName,
1258                                            &entry->var.VendorGuid,
1259                                            &entry->var.Attributes,
1260                                            &size,
1261                                            NULL);
1262                 spin_unlock_irq(&efivars->lock);
1263
1264                 mutex_lock(&inode->i_mutex);
1265                 inode->i_private = entry;
1266                 i_size_write(inode, size + sizeof(entry->var.Attributes));
1267                 mutex_unlock(&inode->i_mutex);
1268                 d_add(dentry, inode);
1269         }
1270
1271         return 0;
1272
1273 fail_inode:
1274         iput(inode);
1275 fail_name:
1276         kfree(name);
1277 fail:
1278         return err;
1279 }
1280
1281 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1282                                     int flags, const char *dev_name, void *data)
1283 {
1284         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1285 }
1286
1287 static void efivarfs_kill_sb(struct super_block *sb)
1288 {
1289         kill_litter_super(sb);
1290         efivarfs_sb = NULL;
1291 }
1292
1293 static struct file_system_type efivarfs_type = {
1294         .name    = "efivarfs",
1295         .mount   = efivarfs_mount,
1296         .kill_sb = efivarfs_kill_sb,
1297 };
1298 MODULE_ALIAS_FS("efivarfs");
1299
1300 /*
1301  * Handle negative dentry.
1302  */
1303 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1304                                       unsigned int flags)
1305 {
1306         if (dentry->d_name.len > NAME_MAX)
1307                 return ERR_PTR(-ENAMETOOLONG);
1308         d_add(dentry, NULL);
1309         return NULL;
1310 }
1311
1312 static const struct inode_operations efivarfs_dir_inode_operations = {
1313         .lookup = efivarfs_lookup,
1314         .unlink = efivarfs_unlink,
1315         .create = efivarfs_create,
1316 };
1317
1318 #ifdef CONFIG_EFI_VARS_PSTORE
1319
1320 static int efi_pstore_open(struct pstore_info *psi)
1321 {
1322         struct efivars *efivars = psi->data;
1323
1324         spin_lock_irq(&efivars->lock);
1325         efivars->walk_entry = list_first_entry(&efivars->list,
1326                                                struct efivar_entry, list);
1327         return 0;
1328 }
1329
1330 static int efi_pstore_close(struct pstore_info *psi)
1331 {
1332         struct efivars *efivars = psi->data;
1333
1334         spin_unlock_irq(&efivars->lock);
1335         return 0;
1336 }
1337
1338 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1339                                int *count, struct timespec *timespec,
1340                                char **buf, struct pstore_info *psi)
1341 {
1342         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1343         struct efivars *efivars = psi->data;
1344         char name[DUMP_NAME_LEN];
1345         int i;
1346         int cnt;
1347         unsigned int part, size;
1348         unsigned long time;
1349
1350         while (&efivars->walk_entry->list != &efivars->list) {
1351                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1352                                  vendor)) {
1353                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1354                                 name[i] = efivars->walk_entry->var.VariableName[i];
1355                         }
1356                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1357                                    type, &part, &cnt, &time) == 4) {
1358                                 *id = part;
1359                                 *count = cnt;
1360                                 timespec->tv_sec = time;
1361                                 timespec->tv_nsec = 0;
1362                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1363                                    type, &part, &time) == 3) {
1364                                 /*
1365                                  * Check if an old format,
1366                                  * which doesn't support holding
1367                                  * multiple logs, remains.
1368                                  */
1369                                 *id = part;
1370                                 *count = 0;
1371                                 timespec->tv_sec = time;
1372                                 timespec->tv_nsec = 0;
1373                         } else {
1374                                 efivars->walk_entry = list_entry(
1375                                                 efivars->walk_entry->list.next,
1376                                                 struct efivar_entry, list);
1377                                 continue;
1378                         }
1379
1380                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1381                         size = efivars->walk_entry->var.DataSize;
1382                         *buf = kmalloc(size, GFP_KERNEL);
1383                         if (*buf == NULL)
1384                                 return -ENOMEM;
1385                         memcpy(*buf, efivars->walk_entry->var.Data,
1386                                size);
1387                         efivars->walk_entry = list_entry(
1388                                         efivars->walk_entry->list.next,
1389                                         struct efivar_entry, list);
1390                         return size;
1391                 }
1392                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1393                                                  struct efivar_entry, list);
1394         }
1395         return 0;
1396 }
1397
1398 static int efi_pstore_write(enum pstore_type_id type,
1399                 enum kmsg_dump_reason reason, u64 *id,
1400                 unsigned int part, int count, size_t size,
1401                 struct pstore_info *psi)
1402 {
1403         char name[DUMP_NAME_LEN];
1404         efi_char16_t efi_name[DUMP_NAME_LEN];
1405         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1406         struct efivars *efivars = psi->data;
1407         int i, ret = 0;
1408         efi_status_t status = EFI_NOT_FOUND;
1409         unsigned long flags;
1410
1411         if (pstore_cannot_block_path(reason)) {
1412                 /*
1413                  * If the lock is taken by another cpu in non-blocking path,
1414                  * this driver returns without entering firmware to avoid
1415                  * hanging up.
1416                  */
1417                 if (!spin_trylock_irqsave(&efivars->lock, flags))
1418                         return -EBUSY;
1419         } else
1420                 spin_lock_irqsave(&efivars->lock, flags);
1421
1422         /*
1423          * Check if there is a space enough to log.
1424          * size: a size of logging data
1425          * DUMP_NAME_LEN * 2: a maximum size of variable name
1426          */
1427
1428         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1429                                          size + DUMP_NAME_LEN * 2);
1430
1431         if (status) {
1432                 spin_unlock_irqrestore(&efivars->lock, flags);
1433                 *id = part;
1434                 return -ENOSPC;
1435         }
1436
1437         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1438                 get_seconds());
1439
1440         for (i = 0; i < DUMP_NAME_LEN; i++)
1441                 efi_name[i] = name[i];
1442
1443         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1444                                    size, psi->buf);
1445
1446         spin_unlock_irqrestore(&efivars->lock, flags);
1447
1448         if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
1449                 schedule_work(&efivar_work);
1450
1451         *id = part;
1452         return ret;
1453 };
1454
1455 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1456                             struct timespec time, struct pstore_info *psi)
1457 {
1458         char name[DUMP_NAME_LEN];
1459         efi_char16_t efi_name[DUMP_NAME_LEN];
1460         char name_old[DUMP_NAME_LEN];
1461         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1462         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1463         struct efivars *efivars = psi->data;
1464         struct efivar_entry *entry, *found = NULL;
1465         int i;
1466
1467         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1468                 time.tv_sec);
1469
1470         spin_lock_irq(&efivars->lock);
1471
1472         for (i = 0; i < DUMP_NAME_LEN; i++)
1473                 efi_name[i] = name[i];
1474
1475         /*
1476          * Clean up an entry with the same name
1477          */
1478
1479         list_for_each_entry(entry, &efivars->list, list) {
1480                 get_var_data_locked(efivars, &entry->var);
1481
1482                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1483                         continue;
1484                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1485                                   utf16_strlen(efi_name))) {
1486                         /*
1487                          * Check if an old format,
1488                          * which doesn't support holding
1489                          * multiple logs, remains.
1490                          */
1491                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1492                                 (unsigned int)id, time.tv_sec);
1493
1494                         for (i = 0; i < DUMP_NAME_LEN; i++)
1495                                 efi_name_old[i] = name_old[i];
1496
1497                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1498                                           utf16_strlen(efi_name_old)))
1499                                 continue;
1500                 }
1501
1502                 /* found */
1503                 found = entry;
1504                 efivars->ops->set_variable(entry->var.VariableName,
1505                                            &entry->var.VendorGuid,
1506                                            PSTORE_EFI_ATTRIBUTES,
1507                                            0, NULL);
1508                 break;
1509         }
1510
1511         if (found)
1512                 list_del(&found->list);
1513
1514         spin_unlock_irq(&efivars->lock);
1515
1516         if (found)
1517                 efivar_unregister(found);
1518
1519         return 0;
1520 }
1521
1522 static struct pstore_info efi_pstore_info = {
1523         .owner          = THIS_MODULE,
1524         .name           = "efi",
1525         .open           = efi_pstore_open,
1526         .close          = efi_pstore_close,
1527         .read           = efi_pstore_read,
1528         .write          = efi_pstore_write,
1529         .erase          = efi_pstore_erase,
1530 };
1531
1532 static void efivar_pstore_register(struct efivars *efivars)
1533 {
1534         efivars->efi_pstore_info = efi_pstore_info;
1535         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1536         if (efivars->efi_pstore_info.buf) {
1537                 efivars->efi_pstore_info.bufsize = 1024;
1538                 efivars->efi_pstore_info.data = efivars;
1539                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1540                 pstore_register(&efivars->efi_pstore_info);
1541         }
1542 }
1543 #else
1544 static void efivar_pstore_register(struct efivars *efivars)
1545 {
1546         return;
1547 }
1548 #endif
1549
1550 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1551                              struct bin_attribute *bin_attr,
1552                              char *buf, loff_t pos, size_t count)
1553 {
1554         struct efi_variable *new_var = (struct efi_variable *)buf;
1555         struct efivars *efivars = bin_attr->private;
1556         struct efivar_entry *search_efivar, *n;
1557         unsigned long strsize1, strsize2;
1558         efi_status_t status = EFI_NOT_FOUND;
1559         int found = 0;
1560
1561         if (!capable(CAP_SYS_ADMIN))
1562                 return -EACCES;
1563
1564         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1565             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1566                 printk(KERN_ERR "efivars: Malformed variable content\n");
1567                 return -EINVAL;
1568         }
1569
1570         spin_lock_irq(&efivars->lock);
1571
1572         /*
1573          * Does this variable already exist?
1574          */
1575         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1576                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1577                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1578                 if (strsize1 == strsize2 &&
1579                         !memcmp(&(search_efivar->var.VariableName),
1580                                 new_var->VariableName, strsize1) &&
1581                         !efi_guidcmp(search_efivar->var.VendorGuid,
1582                                 new_var->VendorGuid)) {
1583                         found = 1;
1584                         break;
1585                 }
1586         }
1587         if (found) {
1588                 spin_unlock_irq(&efivars->lock);
1589                 return -EINVAL;
1590         }
1591
1592         status = check_var_size_locked(efivars, new_var->Attributes,
1593                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
1594
1595         if (status && status != EFI_UNSUPPORTED) {
1596                 spin_unlock_irq(&efivars->lock);
1597                 return efi_status_to_err(status);
1598         }
1599
1600         /* now *really* create the variable via EFI */
1601         status = efivars->ops->set_variable(new_var->VariableName,
1602                                             &new_var->VendorGuid,
1603                                             new_var->Attributes,
1604                                             new_var->DataSize,
1605                                             new_var->Data);
1606
1607         if (status != EFI_SUCCESS) {
1608                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1609                         status);
1610                 spin_unlock_irq(&efivars->lock);
1611                 return -EIO;
1612         }
1613         spin_unlock_irq(&efivars->lock);
1614
1615         /* Create the entry in sysfs.  Locking is not required here */
1616         status = efivar_create_sysfs_entry(efivars,
1617                                            utf16_strsize(new_var->VariableName,
1618                                                          1024),
1619                                            new_var->VariableName,
1620                                            &new_var->VendorGuid);
1621         if (status) {
1622                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1623         }
1624         return count;
1625 }
1626
1627 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1628                              struct bin_attribute *bin_attr,
1629                              char *buf, loff_t pos, size_t count)
1630 {
1631         struct efi_variable *del_var = (struct efi_variable *)buf;
1632         struct efivars *efivars = bin_attr->private;
1633         struct efivar_entry *search_efivar, *n;
1634         unsigned long strsize1, strsize2;
1635         efi_status_t status = EFI_NOT_FOUND;
1636         int found = 0;
1637
1638         if (!capable(CAP_SYS_ADMIN))
1639                 return -EACCES;
1640
1641         spin_lock_irq(&efivars->lock);
1642
1643         /*
1644          * Does this variable already exist?
1645          */
1646         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1647                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1648                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1649                 if (strsize1 == strsize2 &&
1650                         !memcmp(&(search_efivar->var.VariableName),
1651                                 del_var->VariableName, strsize1) &&
1652                         !efi_guidcmp(search_efivar->var.VendorGuid,
1653                                 del_var->VendorGuid)) {
1654                         found = 1;
1655                         break;
1656                 }
1657         }
1658         if (!found) {
1659                 spin_unlock_irq(&efivars->lock);
1660                 return -EINVAL;
1661         }
1662         /* force the Attributes/DataSize to 0 to ensure deletion */
1663         del_var->Attributes = 0;
1664         del_var->DataSize = 0;
1665
1666         status = efivars->ops->set_variable(del_var->VariableName,
1667                                             &del_var->VendorGuid,
1668                                             del_var->Attributes,
1669                                             del_var->DataSize,
1670                                             del_var->Data);
1671
1672         if (status != EFI_SUCCESS) {
1673                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1674                         status);
1675                 spin_unlock_irq(&efivars->lock);
1676                 return -EIO;
1677         }
1678         list_del(&search_efivar->list);
1679         /* We need to release this lock before unregistering. */
1680         spin_unlock_irq(&efivars->lock);
1681         efivar_unregister(search_efivar);
1682
1683         /* It's dead Jim.... */
1684         return count;
1685 }
1686
1687 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1688 {
1689         struct efivar_entry *entry, *n;
1690         struct efivars *efivars = &__efivars;
1691         unsigned long strsize1, strsize2;
1692         bool found = false;
1693
1694         strsize1 = utf16_strsize(variable_name, 1024);
1695         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1696                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1697                 if (strsize1 == strsize2 &&
1698                         !memcmp(variable_name, &(entry->var.VariableName),
1699                                 strsize2) &&
1700                         !efi_guidcmp(entry->var.VendorGuid,
1701                                 *vendor)) {
1702                         found = true;
1703                         break;
1704                 }
1705         }
1706         return found;
1707 }
1708
1709 /*
1710  * Returns the size of variable_name, in bytes, including the
1711  * terminating NULL character, or variable_name_size if no NULL
1712  * character is found among the first variable_name_size bytes.
1713  */
1714 static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1715                                        unsigned long variable_name_size)
1716 {
1717         unsigned long len;
1718         efi_char16_t c;
1719
1720         /*
1721          * The variable name is, by definition, a NULL-terminated
1722          * string, so make absolutely sure that variable_name_size is
1723          * the value we expect it to be. If not, return the real size.
1724          */
1725         for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1726                 c = variable_name[(len / sizeof(c)) - 1];
1727                 if (!c)
1728                         break;
1729         }
1730
1731         return min(len, variable_name_size);
1732 }
1733
1734 static void efivar_update_sysfs_entries(struct work_struct *work)
1735 {
1736         struct efivars *efivars = &__efivars;
1737         efi_guid_t vendor;
1738         efi_char16_t *variable_name;
1739         unsigned long variable_name_size = 1024;
1740         efi_status_t status = EFI_NOT_FOUND;
1741         bool found;
1742
1743         /* Add new sysfs entries */
1744         while (1) {
1745                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1746                 if (!variable_name) {
1747                         pr_err("efivars: Memory allocation failed.\n");
1748                         return;
1749                 }
1750
1751                 spin_lock_irq(&efivars->lock);
1752                 found = false;
1753                 while (1) {
1754                         variable_name_size = 1024;
1755                         status = efivars->ops->get_next_variable(
1756                                                         &variable_name_size,
1757                                                         variable_name,
1758                                                         &vendor);
1759                         if (status != EFI_SUCCESS) {
1760                                 break;
1761                         } else {
1762                                 if (!variable_is_present(variable_name,
1763                                     &vendor)) {
1764                                         found = true;
1765                                         break;
1766                                 }
1767                         }
1768                 }
1769                 spin_unlock_irq(&efivars->lock);
1770
1771                 if (!found) {
1772                         kfree(variable_name);
1773                         break;
1774                 } else {
1775                         variable_name_size = var_name_strnsize(variable_name,
1776                                                                variable_name_size);
1777                         efivar_create_sysfs_entry(efivars,
1778                                                   variable_name_size,
1779                                                   variable_name, &vendor);
1780                 }
1781         }
1782 }
1783
1784 /*
1785  * Let's not leave out systab information that snuck into
1786  * the efivars driver
1787  */
1788 static ssize_t systab_show(struct kobject *kobj,
1789                            struct kobj_attribute *attr, char *buf)
1790 {
1791         char *str = buf;
1792
1793         if (!kobj || !buf)
1794                 return -EINVAL;
1795
1796         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1797                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1798         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1799                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1800         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1801                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1802         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1803                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1804         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1805                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1806         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1807                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1808         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1809                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1810
1811         return str - buf;
1812 }
1813
1814 static struct kobj_attribute efi_attr_systab =
1815                         __ATTR(systab, 0400, systab_show, NULL);
1816
1817 static struct attribute *efi_subsys_attrs[] = {
1818         &efi_attr_systab.attr,
1819         NULL,   /* maybe more in the future? */
1820 };
1821
1822 static struct attribute_group efi_subsys_attr_group = {
1823         .attrs = efi_subsys_attrs,
1824 };
1825
1826 static struct kobject *efi_kobj;
1827
1828 /*
1829  * efivar_create_sysfs_entry()
1830  * Requires:
1831  *    variable_name_size = number of bytes required to hold
1832  *                         variable_name (not counting the NULL
1833  *                         character at the end.
1834  *    efivars->lock is not held on entry or exit.
1835  * Returns 1 on failure, 0 on success
1836  */
1837 static int
1838 efivar_create_sysfs_entry(struct efivars *efivars,
1839                           unsigned long variable_name_size,
1840                           efi_char16_t *variable_name,
1841                           efi_guid_t *vendor_guid)
1842 {
1843         int i, short_name_size;
1844         char *short_name;
1845         struct efivar_entry *new_efivar;
1846
1847         /*
1848          * Length of the variable bytes in ASCII, plus the '-' separator,
1849          * plus the GUID, plus trailing NUL
1850          */
1851         short_name_size = variable_name_size / sizeof(efi_char16_t)
1852                                 + 1 + GUID_LEN + 1;
1853
1854         short_name = kzalloc(short_name_size, GFP_KERNEL);
1855         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1856
1857         if (!short_name || !new_efivar)  {
1858                 kfree(short_name);
1859                 kfree(new_efivar);
1860                 return 1;
1861         }
1862
1863         new_efivar->efivars = efivars;
1864         memcpy(new_efivar->var.VariableName, variable_name,
1865                 variable_name_size);
1866         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1867
1868         /* Convert Unicode to normal chars (assume top bits are 0),
1869            ala UTF-8 */
1870         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1871                 short_name[i] = variable_name[i] & 0xFF;
1872         }
1873         /* This is ugly, but necessary to separate one vendor's
1874            private variables from another's.         */
1875
1876         *(short_name + strlen(short_name)) = '-';
1877         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1878
1879         new_efivar->kobj.kset = efivars->kset;
1880         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1881                                  "%s", short_name);
1882         if (i) {
1883                 kfree(short_name);
1884                 kfree(new_efivar);
1885                 return 1;
1886         }
1887
1888         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1889         kfree(short_name);
1890         short_name = NULL;
1891
1892         spin_lock_irq(&efivars->lock);
1893         list_add(&new_efivar->list, &efivars->list);
1894         spin_unlock_irq(&efivars->lock);
1895
1896         return 0;
1897 }
1898
1899 static int
1900 create_efivars_bin_attributes(struct efivars *efivars)
1901 {
1902         struct bin_attribute *attr;
1903         int error;
1904
1905         /* new_var */
1906         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1907         if (!attr)
1908                 return -ENOMEM;
1909
1910         attr->attr.name = "new_var";
1911         attr->attr.mode = 0200;
1912         attr->write = efivar_create;
1913         attr->private = efivars;
1914         efivars->new_var = attr;
1915
1916         /* del_var */
1917         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1918         if (!attr) {
1919                 error = -ENOMEM;
1920                 goto out_free;
1921         }
1922         attr->attr.name = "del_var";
1923         attr->attr.mode = 0200;
1924         attr->write = efivar_delete;
1925         attr->private = efivars;
1926         efivars->del_var = attr;
1927
1928         sysfs_bin_attr_init(efivars->new_var);
1929         sysfs_bin_attr_init(efivars->del_var);
1930
1931         /* Register */
1932         error = sysfs_create_bin_file(&efivars->kset->kobj,
1933                                       efivars->new_var);
1934         if (error) {
1935                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1936                         " due to error %d\n", error);
1937                 goto out_free;
1938         }
1939         error = sysfs_create_bin_file(&efivars->kset->kobj,
1940                                       efivars->del_var);
1941         if (error) {
1942                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1943                         " due to error %d\n", error);
1944                 sysfs_remove_bin_file(&efivars->kset->kobj,
1945                                       efivars->new_var);
1946                 goto out_free;
1947         }
1948
1949         return 0;
1950 out_free:
1951         kfree(efivars->del_var);
1952         efivars->del_var = NULL;
1953         kfree(efivars->new_var);
1954         efivars->new_var = NULL;
1955         return error;
1956 }
1957
1958 void unregister_efivars(struct efivars *efivars)
1959 {
1960         struct efivar_entry *entry, *n;
1961
1962         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1963                 spin_lock_irq(&efivars->lock);
1964                 list_del(&entry->list);
1965                 spin_unlock_irq(&efivars->lock);
1966                 efivar_unregister(entry);
1967         }
1968         if (efivars->new_var)
1969                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1970         if (efivars->del_var)
1971                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1972         kfree(efivars->new_var);
1973         kfree(efivars->del_var);
1974         kobject_put(efivars->kobject);
1975         kset_unregister(efivars->kset);
1976 }
1977 EXPORT_SYMBOL_GPL(unregister_efivars);
1978
1979 /*
1980  * Print a warning when duplicate EFI variables are encountered and
1981  * disable the sysfs workqueue since the firmware is buggy.
1982  */
1983 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1984                              unsigned long len16)
1985 {
1986         size_t i, len8 = len16 / sizeof(efi_char16_t);
1987         char *s8;
1988
1989         /*
1990          * Disable the workqueue since the algorithm it uses for
1991          * detecting new variables won't work with this buggy
1992          * implementation of GetNextVariableName().
1993          */
1994         efivar_wq_enabled = false;
1995
1996         s8 = kzalloc(len8, GFP_KERNEL);
1997         if (!s8)
1998                 return;
1999
2000         for (i = 0; i < len8; i++)
2001                 s8[i] = s16[i];
2002
2003         printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
2004                s8, vendor_guid);
2005         kfree(s8);
2006 }
2007
2008 int register_efivars(struct efivars *efivars,
2009                      const struct efivar_operations *ops,
2010                      struct kobject *parent_kobj)
2011 {
2012         efi_status_t status = EFI_NOT_FOUND;
2013         efi_guid_t vendor_guid;
2014         efi_char16_t *variable_name;
2015         unsigned long variable_name_size = 1024;
2016         int error = 0;
2017
2018         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
2019         if (!variable_name) {
2020                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
2021                 return -ENOMEM;
2022         }
2023
2024         spin_lock_init(&efivars->lock);
2025         INIT_LIST_HEAD(&efivars->list);
2026         efivars->ops = ops;
2027
2028         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
2029         if (!efivars->kset) {
2030                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
2031                 error = -ENOMEM;
2032                 goto out;
2033         }
2034
2035         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
2036         if (!efivars->kobject) {
2037                 pr_err("efivars: Subsystem registration failed.\n");
2038                 error = -ENOMEM;
2039                 kset_unregister(efivars->kset);
2040                 goto out;
2041         }
2042
2043         /*
2044          * Per EFI spec, the maximum storage allocated for both
2045          * the variable name and variable data is 1024 bytes.
2046          */
2047
2048         do {
2049                 variable_name_size = 1024;
2050
2051                 status = ops->get_next_variable(&variable_name_size,
2052                                                 variable_name,
2053                                                 &vendor_guid);
2054                 switch (status) {
2055                 case EFI_SUCCESS:
2056                         variable_name_size = var_name_strnsize(variable_name,
2057                                                                variable_name_size);
2058
2059                         /*
2060                          * Some firmware implementations return the
2061                          * same variable name on multiple calls to
2062                          * get_next_variable(). Terminate the loop
2063                          * immediately as there is no guarantee that
2064                          * we'll ever see a different variable name,
2065                          * and may end up looping here forever.
2066                          */
2067                         if (variable_is_present(variable_name, &vendor_guid)) {
2068                                 dup_variable_bug(variable_name, &vendor_guid,
2069                                                  variable_name_size);
2070                                 status = EFI_NOT_FOUND;
2071                                 break;
2072                         }
2073
2074                         efivar_create_sysfs_entry(efivars,
2075                                                   variable_name_size,
2076                                                   variable_name,
2077                                                   &vendor_guid);
2078                         break;
2079                 case EFI_NOT_FOUND:
2080                         break;
2081                 default:
2082                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
2083                                 status);
2084                         status = EFI_NOT_FOUND;
2085                         break;
2086                 }
2087         } while (status != EFI_NOT_FOUND);
2088
2089         error = create_efivars_bin_attributes(efivars);
2090         if (error)
2091                 unregister_efivars(efivars);
2092
2093         if (!efivars_pstore_disable)
2094                 efivar_pstore_register(efivars);
2095
2096         register_filesystem(&efivarfs_type);
2097
2098 out:
2099         kfree(variable_name);
2100
2101         return error;
2102 }
2103 EXPORT_SYMBOL_GPL(register_efivars);
2104
2105 /*
2106  * For now we register the efi subsystem with the firmware subsystem
2107  * and the vars subsystem with the efi subsystem.  In the future, it
2108  * might make sense to split off the efi subsystem into its own
2109  * driver, but for now only efivars will register with it, so just
2110  * include it here.
2111  */
2112
2113 static int __init
2114 efivars_init(void)
2115 {
2116         int error = 0;
2117
2118         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2119                EFIVARS_DATE);
2120
2121         if (!efi_enabled(EFI_RUNTIME_SERVICES))
2122                 return 0;
2123
2124         /* For now we'll register the efi directory at /sys/firmware/efi */
2125         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2126         if (!efi_kobj) {
2127                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2128                 return -ENOMEM;
2129         }
2130
2131         ops.get_variable = efi.get_variable;
2132         ops.set_variable = efi.set_variable;
2133         ops.get_next_variable = efi.get_next_variable;
2134         ops.query_variable_info = efi.query_variable_info;
2135
2136         error = register_efivars(&__efivars, &ops, efi_kobj);
2137         if (error)
2138                 goto err_put;
2139
2140         /* Don't forget the systab entry */
2141         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2142         if (error) {
2143                 printk(KERN_ERR
2144                        "efivars: Sysfs attribute export failed with error %d.\n",
2145                        error);
2146                 goto err_unregister;
2147         }
2148
2149         return 0;
2150
2151 err_unregister:
2152         unregister_efivars(&__efivars);
2153 err_put:
2154         kobject_put(efi_kobj);
2155         return error;
2156 }
2157
2158 static void __exit
2159 efivars_exit(void)
2160 {
2161         cancel_work_sync(&efivar_work);
2162
2163         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2164                 unregister_efivars(&__efivars);
2165                 kobject_put(efi_kobj);
2166         }
2167 }
2168
2169 module_init(efivars_init);
2170 module_exit(efivars_exit);
2171