drivers/firmware/efivars.c

   1 /*
   2  * EFI Variables - efivars.c
   3  *
   4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
   5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
   6  *
   7  * This code takes all variables accessible from EFI runtime and
   8  *  exports them via sysfs
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  * Changelog:
  25  *
  26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
  27  *   remove check for efi_enabled in exit
  28  *   add MODULE_VERSION
  29  *
  30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
  31  *   minor bug fixes
  32  *
  33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
  34  *   converted driver to export variable information via sysfs
  35  *   and moved to drivers/firmware directory
  36  *   bumped revision number to v0.07 to reflect conversion & move
  37  *
  38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
  39  *   fix locking per Peter Chubb's findings
  40  *
  41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
  42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
  43  *
  44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
  45  *   use list_for_each_safe when deleting vars.
  46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
  47  *   v0.04 release to linux-ia64@linuxia64.org
  48  *
  49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
  50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
  51  *   efi.c own the /proc/efi directory.
  52  *   v0.03 release to linux-ia64@linuxia64.org
  53  *
  54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  55  *   At the request of Stephane, moved ownership of /proc/efi
  56  *   to efi.c, and now efivars lives under /proc/efi/vars.
  57  *
  58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  59  *   Feedback received from Stephane Eranian incorporated.
  60  *   efivar_write() checks copy_from_user() return value.
  61  *   efivar_read/write() returns proper errno.
  62  *   v0.02 release to linux-ia64@linuxia64.org
  63  *
  64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
  65  *   v0.01 release to linux-ia64@linuxia64.org
  66  */
  67
  68 #include <linux/capability.h>
  69 #include <linux/types.h>
  70 #include <linux/errno.h>
  71 #include <linux/init.h>
  72 #include <linux/mm.h>
  73 #include <linux/module.h>
  74 #include <linux/string.h>
  75 #include <linux/smp.h>
  76 #include <linux/efi.h>
  77 #include <linux/sysfs.h>
  78 #include <linux/kobject.h>
  79 #include <linux/device.h>
  80 #include <linux/slab.h>
  81 #include <linux/pstore.h>
  82
  83 #include <asm/uaccess.h>
  84
  85 #define EFIVARS_VERSION "0.08"
  86 #define EFIVARS_DATE "2004-May-17"
  87
  88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  90 MODULE_LICENSE("GPL");
  91 MODULE_VERSION(EFIVARS_VERSION);
  92
  93 #define DUMP_NAME_LEN 52
  94
  95 static bool efivars_pstore_disable =
  96         IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
  97
  98 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
  99
 100 /*
 101  * The maximum size of VariableName + Data = 1024
 102  * Therefore, it's reasonable to save that much
 103  * space in each part of the structure,
 104  * and we use a page for reading/writing.
 105  */
 106
 107 struct efi_variable {
 108         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 109         efi_guid_t    VendorGuid;
 110         unsigned long DataSize;
 111         __u8          Data[1024];
 112         efi_status_t  Status;
 113         __u32         Attributes;
 114 } __attribute__((packed));
 115
 116
 117 struct efivar_entry {
 118         struct efivars *efivars;
 119         struct efi_variable var;
 120         struct list_head list;
 121         struct kobject kobj;
 122 };
 123
 124 struct efivar_attribute {
 125         struct attribute attr;
 126         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 127         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 128 };
 129
 130 static struct efivars __efivars;
 131
 132 #define PSTORE_EFI_ATTRIBUTES \
 133         (EFI_VARIABLE_NON_VOLATILE | \
 134          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 135          EFI_VARIABLE_RUNTIME_ACCESS)
 136
 137 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 138 struct efivar_attribute efivar_attr_##_name = { \
 139         .attr = {.name = __stringify(_name), .mode = _mode}, \
 140         .show = _show, \
 141         .store = _store, \
 142 };
 143
 144 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 145 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 146
 147 /*
 148  * Prototype for sysfs creation function
 149  */
 150 static int
 151 efivar_create_sysfs_entry(struct efivars *efivars,
 152                           unsigned long variable_name_size,
 153                           efi_char16_t *variable_name,
 154                           efi_guid_t *vendor_guid);
 155
 156 /*
 157  * Prototype for workqueue functions updating sysfs entry
 158  */
 159
 160 static void efivar_update_sysfs_entries(struct work_struct *);
 161 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
 162
 163 /* Return the number of unicode characters in data */
 164 static unsigned long
 165 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 166 {
 167         unsigned long length = 0;
 168
 169         while (*s++ != 0 && length < maxlength)
 170                 length++;
 171         return length;
 172 }
 173
 174 static inline unsigned long
 175 utf16_strlen(efi_char16_t *s)
 176 {
 177         return utf16_strnlen(s, ~0UL);
 178 }
 179
 180 /*
 181  * Return the number of bytes is the length of this string
 182  * Note: this is NOT the same as the number of unicode characters
 183  */
 184 static inline unsigned long
 185 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 186 {
 187         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 188 }
 189
 190 static inline int
 191 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 192 {
 193         while (1) {
 194                 if (len == 0)
 195                         return 0;
 196                 if (*a < *b)
 197                         return -1;
 198                 if (*a > *b)
 199                         return 1;
 200                 if (*a == 0) /* implies *b == 0 */
 201                         return 0;
 202                 a++;
 203                 b++;
 204                 len--;
 205         }
 206 }
 207
 208 static bool
 209 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 210                      unsigned long len)
 211 {
 212         struct efi_generic_dev_path *node;
 213         int offset = 0;
 214
 215         node = (struct efi_generic_dev_path *)buffer;
 216
 217         if (len < sizeof(*node))
 218                 return false;
 219
 220         while (offset <= len - sizeof(*node) &&
 221                node->length >= sizeof(*node) &&
 222                 node->length <= len - offset) {
 223                 offset += node->length;
 224
 225                 if ((node->type == EFI_DEV_END_PATH ||
 226                      node->type == EFI_DEV_END_PATH2) &&
 227                     node->sub_type == EFI_DEV_END_ENTIRE)
 228                         return true;
 229
 230                 node = (struct efi_generic_dev_path *)(buffer + offset);
 231         }
 232
 233         /*
 234          * If we're here then either node->length pointed past the end
 235          * of the buffer or we reached the end of the buffer without
 236          * finding a device path end node.
 237          */
 238         return false;
 239 }
 240
 241 static bool
 242 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 243                     unsigned long len)
 244 {
 245         /* An array of 16-bit integers */
 246         if ((len % 2) != 0)
 247                 return false;
 248
 249         return true;
 250 }
 251
 252 static bool
 253 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 254                      unsigned long len)
 255 {
 256         u16 filepathlength;
 257         int i, desclength = 0, namelen;
 258
 259         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 260
 261         /* Either "Boot" or "Driver" followed by four digits of hex */
 262         for (i = match; i < match+4; i++) {
 263                 if (var->VariableName[i] > 127 ||
 264                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 265                         return true;
 266         }
 267
 268         /* Reject it if there's 4 digits of hex and then further content */
 269         if (namelen > match + 4)
 270                 return false;
 271
 272         /* A valid entry must be at least 8 bytes */
 273         if (len < 8)
 274                 return false;
 275
 276         filepathlength = buffer[4] | buffer[5] << 8;
 277
 278         /*
 279          * There's no stored length for the description, so it has to be
 280          * found by hand
 281          */
 282         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 283
 284         /* Each boot entry must have a descriptor */
 285         if (!desclength)
 286                 return false;
 287
 288         /*
 289          * If the sum of the length of the description, the claimed filepath
 290          * length and the original header are greater than the length of the
 291          * variable, it's malformed
 292          */
 293         if ((desclength + filepathlength + 6) > len)
 294                 return false;
 295
 296         /*
 297          * And, finally, check the filepath
 298          */
 299         return validate_device_path(var, match, buffer + desclength + 6,
 300                                     filepathlength);
 301 }
 302
 303 static bool
 304 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 305                 unsigned long len)
 306 {
 307         /* A single 16-bit integer */
 308         if (len != 2)
 309                 return false;
 310
 311         return true;
 312 }
 313
 314 static bool
 315 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 316                       unsigned long len)
 317 {
 318         int i;
 319
 320         for (i = 0; i < len; i++) {
 321                 if (buffer[i] > 127)
 322                         return false;
 323
 324                 if (buffer[i] == 0)
 325                         return true;
 326         }
 327
 328         return false;
 329 }
 330
 331 struct variable_validate {
 332         char *name;
 333         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 334                          unsigned long len);
 335 };
 336
 337 static const struct variable_validate variable_validate[] = {
 338         { "BootNext", validate_uint16 },
 339         { "BootOrder", validate_boot_order },
 340         { "DriverOrder", validate_boot_order },
 341         { "Boot*", validate_load_option },
 342         { "Driver*", validate_load_option },
 343         { "ConIn", validate_device_path },
 344         { "ConInDev", validate_device_path },
 345         { "ConOut", validate_device_path },
 346         { "ConOutDev", validate_device_path },
 347         { "ErrOut", validate_device_path },
 348         { "ErrOutDev", validate_device_path },
 349         { "Timeout", validate_uint16 },
 350         { "Lang", validate_ascii_string },
 351         { "PlatformLang", validate_ascii_string },
 352         { "", NULL },
 353 };
 354
 355 static bool
 356 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 357 {
 358         int i;
 359         u16 *unicode_name = var->VariableName;
 360
 361         for (i = 0; variable_validate[i].validate != NULL; i++) {
 362                 const char *name = variable_validate[i].name;
 363                 int match;
 364
 365                 for (match = 0; ; match++) {
 366                         char c = name[match];
 367                         u16 u = unicode_name[match];
 368
 369                         /* All special variables are plain ascii */
 370                         if (u > 127)
 371                                 return true;
 372
 373                         /* Wildcard in the matching name means we've matched */
 374                         if (c == '*')
 375                                 return variable_validate[i].validate(var,
 376                                                              match, data, len);
 377
 378                         /* Case sensitive match */
 379                         if (c != u)
 380                                 break;
 381
 382                         /* Reached the end of the string while matching */
 383                         if (!c)
 384                                 return variable_validate[i].validate(var,
 385                                                              match, data, len);
 386                 }
 387         }
 388
 389         return true;
 390 }
 391
 392 static efi_status_t
 393 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 394 {
 395         efi_status_t status;
 396
 397         var->DataSize = 1024;
 398         status = efivars->ops->get_variable(var->VariableName,
 399                                             &var->VendorGuid,
 400                                             &var->Attributes,
 401                                             &var->DataSize,
 402                                             var->Data);
 403         return status;
 404 }
 405
 406 static efi_status_t
 407 get_var_data(struct efivars *efivars, struct efi_variable *var)
 408 {
 409         efi_status_t status;
 410         unsigned long flags;
 411
 412         spin_lock_irqsave(&efivars->lock, flags);
 413         status = get_var_data_locked(efivars, var);
 414         spin_unlock_irqrestore(&efivars->lock, flags);
 415
 416         if (status != EFI_SUCCESS) {
 417                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 418                         status);
 419         }
 420         return status;
 421 }
 422
 423 static efi_status_t
 424 check_var_size_locked(struct efivars *efivars, u32 attributes,
 425                         unsigned long size)
 426 {
 427         u64 storage_size, remaining_size, max_size;
 428         efi_status_t status;
 429         const struct efivar_operations *fops = efivars->ops;
 430
 431         if (!efivars->ops->query_variable_info)
 432                 return EFI_UNSUPPORTED;
 433
 434         status = fops->query_variable_info(attributes, &storage_size,
 435                                            &remaining_size, &max_size);
 436
 437         if (status != EFI_SUCCESS)
 438                 return status;
 439
 440         if (!storage_size || size > remaining_size || size > max_size ||
 441             (remaining_size - size) < (storage_size / 2))
 442                 return EFI_OUT_OF_RESOURCES;
 443
 444         return status;
 445 }
 446
 447 static ssize_t
 448 efivar_guid_read(struct efivar_entry *entry, char *buf)
 449 {
 450         struct efi_variable *var = &entry->var;
 451         char *str = buf;
 452
 453         if (!entry || !buf)
 454                 return 0;
 455
 456         efi_guid_unparse(&var->VendorGuid, str);
 457         str += strlen(str);
 458         str += sprintf(str, "\n");
 459
 460         return str - buf;
 461 }
 462
 463 static ssize_t
 464 efivar_attr_read(struct efivar_entry *entry, char *buf)
 465 {
 466         struct efi_variable *var = &entry->var;
 467         char *str = buf;
 468         efi_status_t status;
 469
 470         if (!entry || !buf)
 471                 return -EINVAL;
 472
 473         status = get_var_data(entry->efivars, var);
 474         if (status != EFI_SUCCESS)
 475                 return -EIO;
 476
 477         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 478                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 479         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 480                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 481         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 482                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 483         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 484                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 485         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 486                 str += sprintf(str,
 487                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 488         if (var->Attributes &
 489                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 490                 str += sprintf(str,
 491                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 492         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 493                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 494         return str - buf;
 495 }
 496
 497 static ssize_t
 498 efivar_size_read(struct efivar_entry *entry, char *buf)
 499 {
 500         struct efi_variable *var = &entry->var;
 501         char *str = buf;
 502         efi_status_t status;
 503
 504         if (!entry || !buf)
 505                 return -EINVAL;
 506
 507         status = get_var_data(entry->efivars, var);
 508         if (status != EFI_SUCCESS)
 509                 return -EIO;
 510
 511         str += sprintf(str, "0x%lx\n", var->DataSize);
 512         return str - buf;
 513 }
 514
 515 static ssize_t
 516 efivar_data_read(struct efivar_entry *entry, char *buf)
 517 {
 518         struct efi_variable *var = &entry->var;
 519         efi_status_t status;
 520
 521         if (!entry || !buf)
 522                 return -EINVAL;
 523
 524         status = get_var_data(entry->efivars, var);
 525         if (status != EFI_SUCCESS)
 526                 return -EIO;
 527
 528         memcpy(buf, var->Data, var->DataSize);
 529         return var->DataSize;
 530 }
 531 /*
 532  * We allow each variable to be edited via rewriting the
 533  * entire efi variable structure.
 534  */
 535 static ssize_t
 536 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 537 {
 538         struct efi_variable *new_var, *var = &entry->var;
 539         struct efivars *efivars = entry->efivars;
 540         efi_status_t status = EFI_NOT_FOUND;
 541
 542         if (count != sizeof(struct efi_variable))
 543                 return -EINVAL;
 544
 545         new_var = (struct efi_variable *)buf;
 546         /*
 547          * If only updating the variable data, then the name
 548          * and guid should remain the same
 549          */
 550         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 551                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 552                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 553                 return -EINVAL;
 554         }
 555
 556         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 557                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 558                 return -EINVAL;
 559         }
 560
 561         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 562             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 563                 printk(KERN_ERR "efivars: Malformed variable content\n");
 564                 return -EINVAL;
 565         }
 566
 567         spin_lock_irq(&efivars->lock);
 568
 569         status = check_var_size_locked(efivars, new_var->Attributes,
 570                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 571
 572         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 573                 status = efivars->ops->set_variable(new_var->VariableName,
 574                                                     &new_var->VendorGuid,
 575                                                     new_var->Attributes,
 576                                                     new_var->DataSize,
 577                                                     new_var->Data);
 578
 579         spin_unlock_irq(&efivars->lock);
 580
 581         if (status != EFI_SUCCESS) {
 582                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 583                         status);
 584                 return -EIO;
 585         }
 586
 587         memcpy(&entry->var, new_var, count);
 588         return count;
 589 }
 590
 591 static ssize_t
 592 efivar_show_raw(struct efivar_entry *entry, char *buf)
 593 {
 594         struct efi_variable *var = &entry->var;
 595         efi_status_t status;
 596
 597         if (!entry || !buf)
 598                 return 0;
 599
 600         status = get_var_data(entry->efivars, var);
 601         if (status != EFI_SUCCESS)
 602                 return -EIO;
 603
 604         memcpy(buf, var, sizeof(*var));
 605         return sizeof(*var);
 606 }
 607
 608 /*
 609  * Generic read/write functions that call the specific functions of
 610  * the attributes...
 611  */
 612 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 613                                 char *buf)
 614 {
 615         struct efivar_entry *var = to_efivar_entry(kobj);
 616         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 617         ssize_t ret = -EIO;
 618
 619         if (!capable(CAP_SYS_ADMIN))
 620                 return -EACCES;
 621
 622         if (efivar_attr->show) {
 623                 ret = efivar_attr->show(var, buf);
 624         }
 625         return ret;
 626 }
 627
 628 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 629                                 const char *buf, size_t count)
 630 {
 631         struct efivar_entry *var = to_efivar_entry(kobj);
 632         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 633         ssize_t ret = -EIO;
 634
 635         if (!capable(CAP_SYS_ADMIN))
 636                 return -EACCES;
 637
 638         if (efivar_attr->store)
 639                 ret = efivar_attr->store(var, buf, count);
 640
 641         return ret;
 642 }
 643
 644 static const struct sysfs_ops efivar_attr_ops = {
 645         .show = efivar_attr_show,
 646         .store = efivar_attr_store,
 647 };
 648
 649 static void efivar_release(struct kobject *kobj)
 650 {
 651         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 652         kfree(var);
 653 }
 654
 655 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 656 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 657 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 658 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 659 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 660
 661 static struct attribute *def_attrs[] = {
 662         &efivar_attr_guid.attr,
 663         &efivar_attr_size.attr,
 664         &efivar_attr_attributes.attr,
 665         &efivar_attr_data.attr,
 666         &efivar_attr_raw_var.attr,
 667         NULL,
 668 };
 669
 670 static struct kobj_type efivar_ktype = {
 671         .release = efivar_release,
 672         .sysfs_ops = &efivar_attr_ops,
 673         .default_attrs = def_attrs,
 674 };
 675
 676 static inline void
 677 efivar_unregister(struct efivar_entry *var)
 678 {
 679         kobject_put(&var->kobj);
 680 }
 681
 682 static int efi_status_to_err(efi_status_t status)
 683 {
 684         int err;
 685
 686         switch (status) {
 687         case EFI_INVALID_PARAMETER:
 688                 err = -EINVAL;
 689                 break;
 690         case EFI_OUT_OF_RESOURCES:
 691                 err = -ENOSPC;
 692                 break;
 693         case EFI_DEVICE_ERROR:
 694                 err = -EIO;
 695                 break;
 696         case EFI_WRITE_PROTECTED:
 697                 err = -EROFS;
 698                 break;
 699         case EFI_SECURITY_VIOLATION:
 700                 err = -EACCES;
 701                 break;
 702         case EFI_NOT_FOUND:
 703                 err = -ENOENT;
 704                 break;
 705         default:
 706                 err = -EINVAL;
 707         }
 708
 709         return err;
 710 }
 711
 712 #ifdef CONFIG_EFI_VARS_PSTORE
 713
 714 static int efi_pstore_open(struct pstore_info *psi)
 715 {
 716         struct efivars *efivars = psi->data;
 717
 718         spin_lock_irq(&efivars->lock);
 719         efivars->walk_entry = list_first_entry(&efivars->list,
 720                                                struct efivar_entry, list);
 721         return 0;
 722 }
 723
 724 static int efi_pstore_close(struct pstore_info *psi)
 725 {
 726         struct efivars *efivars = psi->data;
 727
 728         spin_unlock_irq(&efivars->lock);
 729         return 0;
 730 }
 731
 732 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 733                                struct timespec *timespec,
 734                                char **buf, struct pstore_info *psi)
 735 {
 736         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 737         struct efivars *efivars = psi->data;
 738         char name[DUMP_NAME_LEN];
 739         int i;
 740         unsigned int part, size;
 741         unsigned long time;
 742
 743         while (&efivars->walk_entry->list != &efivars->list) {
 744                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 745                                  vendor)) {
 746                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 747                                 name[i] = efivars->walk_entry->var.VariableName[i];
 748                         }
 749                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 750                                 *id = part;
 751                                 timespec->tv_sec = time;
 752                                 timespec->tv_nsec = 0;
 753                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 754                                 size = efivars->walk_entry->var.DataSize;
 755                                 *buf = kmalloc(size, GFP_KERNEL);
 756                                 if (*buf == NULL)
 757                                         return -ENOMEM;
 758                                 memcpy(*buf, efivars->walk_entry->var.Data,
 759                                        size);
 760                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 761                                                    struct efivar_entry, list);
 762                                 return size;
 763                         }
 764                 }
 765                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 766                                                  struct efivar_entry, list);
 767         }
 768         return 0;
 769 }
 770
 771 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
 772                 unsigned int part, size_t size, struct pstore_info *psi)
 773 {
 774         char name[DUMP_NAME_LEN];
 775         char stub_name[DUMP_NAME_LEN];
 776         efi_char16_t efi_name[DUMP_NAME_LEN];
 777         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 778         struct efivars *efivars = psi->data;
 779         struct efivar_entry *entry, *found = NULL;
 780         int i, ret = 0;
 781         efi_status_t status = EFI_NOT_FOUND;
 782         unsigned long flags;
 783
 784         sprintf(stub_name, "dump-type%u-%u-", type, part);
 785         sprintf(name, "%s%lu", stub_name, get_seconds());
 786
 787         spin_lock_irqsave(&efivars->lock, flags);
 788
 789         /*
 790          * Check if there is a space enough to log.
 791          * size: a size of logging data
 792          * DUMP_NAME_LEN * 2: a maximum size of variable name
 793          */
 794
 795         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
 796                                          size + DUMP_NAME_LEN * 2);
 797
 798         if (status) {
 799                 spin_unlock_irqrestore(&efivars->lock, flags);
 800                 *id = part;
 801                 return -ENOSPC;
 802         }
 803
 804         for (i = 0; i < DUMP_NAME_LEN; i++)
 805                 efi_name[i] = stub_name[i];
 806
 807         /*
 808          * Clean up any entries with the same name
 809          */
 810
 811         list_for_each_entry(entry, &efivars->list, list) {
 812                 get_var_data_locked(efivars, &entry->var);
 813
 814                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
 815                         continue;
 816                 if (utf16_strncmp(entry->var.VariableName, efi_name,
 817                                   utf16_strlen(efi_name)))
 818                         continue;
 819                 /* Needs to be a prefix */
 820                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 821                         continue;
 822
 823                 /* found */
 824                 found = entry;
 825                 efivars->ops->set_variable(entry->var.VariableName,
 826                                            &entry->var.VendorGuid,
 827                                            PSTORE_EFI_ATTRIBUTES,
 828                                            0, NULL);
 829         }
 830
 831         if (found)
 832                 list_del(&found->list);
 833
 834         for (i = 0; i < DUMP_NAME_LEN; i++)
 835                 efi_name[i] = name[i];
 836
 837         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 838                                    size, psi->buf);
 839
 840         spin_unlock_irqrestore(&efivars->lock, flags);
 841
 842         if (found)
 843                 efivar_unregister(found);
 844
 845         schedule_work(&efivar_work);
 846
 847         *id = part;
 848         return ret;
 849 };
 850
 851 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 852                             struct pstore_info *psi)
 853 {
 854         efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
 855
 856         return 0;
 857 }
 858
 859 static struct pstore_info efi_pstore_info = {
 860         .owner          = THIS_MODULE,
 861         .name           = "efi",
 862         .open           = efi_pstore_open,
 863         .close          = efi_pstore_close,
 864         .read           = efi_pstore_read,
 865         .write          = efi_pstore_write,
 866         .erase          = efi_pstore_erase,
 867 };
 868
 869 static void efivar_pstore_register(struct efivars *efivars)
 870 {
 871         efivars->efi_pstore_info = efi_pstore_info;
 872         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
 873         if (efivars->efi_pstore_info.buf) {
 874                 efivars->efi_pstore_info.bufsize = 1024;
 875                 efivars->efi_pstore_info.data = efivars;
 876                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
 877                 pstore_register(&efivars->efi_pstore_info);
 878         }
 879 }
 880 #else
 881 static void efivar_pstore_register(struct efivars *efivars)
 882 {
 883         return;
 884 }
 885 #endif
 886
 887 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 888                              struct bin_attribute *bin_attr,
 889                              char *buf, loff_t pos, size_t count)
 890 {
 891         struct efi_variable *new_var = (struct efi_variable *)buf;
 892         struct efivars *efivars = bin_attr->private;
 893         struct efivar_entry *search_efivar, *n;
 894         unsigned long strsize1, strsize2;
 895         efi_status_t status = EFI_NOT_FOUND;
 896         int found = 0;
 897
 898         if (!capable(CAP_SYS_ADMIN))
 899                 return -EACCES;
 900
 901         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 902             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 903                 printk(KERN_ERR "efivars: Malformed variable content\n");
 904                 return -EINVAL;
 905         }
 906
 907         spin_lock_irq(&efivars->lock);
 908
 909         /*
 910          * Does this variable already exist?
 911          */
 912         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 913                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 914                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
 915                 if (strsize1 == strsize2 &&
 916                         !memcmp(&(search_efivar->var.VariableName),
 917                                 new_var->VariableName, strsize1) &&
 918                         !efi_guidcmp(search_efivar->var.VendorGuid,
 919                                 new_var->VendorGuid)) {
 920                         found = 1;
 921                         break;
 922                 }
 923         }
 924         if (found) {
 925                 spin_unlock_irq(&efivars->lock);
 926                 return -EINVAL;
 927         }
 928
 929         status = check_var_size_locked(efivars, new_var->Attributes,
 930                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 931
 932         if (status && status != EFI_UNSUPPORTED) {
 933                 spin_unlock_irq(&efivars->lock);
 934                 return efi_status_to_err(status);
 935         }
 936
 937         /* now *really* create the variable via EFI */
 938         status = efivars->ops->set_variable(new_var->VariableName,
 939                                             &new_var->VendorGuid,
 940                                             new_var->Attributes,
 941                                             new_var->DataSize,
 942                                             new_var->Data);
 943
 944         if (status != EFI_SUCCESS) {
 945                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 946                         status);
 947                 spin_unlock_irq(&efivars->lock);
 948                 return -EIO;
 949         }
 950         spin_unlock_irq(&efivars->lock);
 951
 952         /* Create the entry in sysfs.  Locking is not required here */
 953         status = efivar_create_sysfs_entry(efivars,
 954                                            utf16_strsize(new_var->VariableName,
 955                                                          1024),
 956                                            new_var->VariableName,
 957                                            &new_var->VendorGuid);
 958         if (status) {
 959                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 960         }
 961         return count;
 962 }
 963
 964 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 965                              struct bin_attribute *bin_attr,
 966                              char *buf, loff_t pos, size_t count)
 967 {
 968         struct efi_variable *del_var = (struct efi_variable *)buf;
 969         struct efivars *efivars = bin_attr->private;
 970         struct efivar_entry *search_efivar, *n;
 971         unsigned long strsize1, strsize2;
 972         efi_status_t status = EFI_NOT_FOUND;
 973         int found = 0;
 974
 975         if (!capable(CAP_SYS_ADMIN))
 976                 return -EACCES;
 977
 978         spin_lock_irq(&efivars->lock);
 979
 980         /*
 981          * Does this variable already exist?
 982          */
 983         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 984                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 985                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
 986                 if (strsize1 == strsize2 &&
 987                         !memcmp(&(search_efivar->var.VariableName),
 988                                 del_var->VariableName, strsize1) &&
 989                         !efi_guidcmp(search_efivar->var.VendorGuid,
 990                                 del_var->VendorGuid)) {
 991                         found = 1;
 992                         break;
 993                 }
 994         }
 995         if (!found) {
 996                 spin_unlock_irq(&efivars->lock);
 997                 return -EINVAL;
 998         }
 999         /* force the Attributes/DataSize to 0 to ensure deletion */
1000         del_var->Attributes = 0;
1001         del_var->DataSize = 0;
1002
1003         status = efivars->ops->set_variable(del_var->VariableName,
1004                                             &del_var->VendorGuid,
1005                                             del_var->Attributes,
1006                                             del_var->DataSize,
1007                                             del_var->Data);
1008
1009         if (status != EFI_SUCCESS) {
1010                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1011                         status);
1012                 spin_unlock_irq(&efivars->lock);
1013                 return -EIO;
1014         }
1015         list_del(&search_efivar->list);
1016         /* We need to release this lock before unregistering. */
1017         spin_unlock_irq(&efivars->lock);
1018         efivar_unregister(search_efivar);
1019
1020         /* It's dead Jim.... */
1021         return count;
1022 }
1023
1024 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1025 {
1026         struct efivar_entry *entry, *n;
1027         struct efivars *efivars = &__efivars;
1028         unsigned long strsize1, strsize2;
1029         bool found = false;
1030
1031         strsize1 = utf16_strsize(variable_name, 1024);
1032         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1033                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1034                 if (strsize1 == strsize2 &&
1035                         !memcmp(variable_name, &(entry->var.VariableName),
1036                                 strsize2) &&
1037                         !efi_guidcmp(entry->var.VendorGuid,
1038                                 *vendor)) {
1039                         found = true;
1040                         break;
1041                 }
1042         }
1043         return found;
1044 }
1045
1046 static void efivar_update_sysfs_entries(struct work_struct *work)
1047 {
1048         struct efivars *efivars = &__efivars;
1049         efi_guid_t vendor;
1050         efi_char16_t *variable_name;
1051         unsigned long variable_name_size = 1024;
1052         efi_status_t status = EFI_NOT_FOUND;
1053         bool found;
1054
1055         /* Add new sysfs entries */
1056         while (1) {
1057                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1058                 if (!variable_name) {
1059                         pr_err("efivars: Memory allocation failed.\n");
1060                         return;
1061                 }
1062
1063                 spin_lock_irq(&efivars->lock);
1064                 found = false;
1065                 while (1) {
1066                         variable_name_size = 1024;
1067                         status = efivars->ops->get_next_variable(
1068                                                         &variable_name_size,
1069                                                         variable_name,
1070                                                         &vendor);
1071                         if (status != EFI_SUCCESS) {
1072                                 break;
1073                         } else {
1074                                 if (!variable_is_present(variable_name,
1075                                     &vendor)) {
1076                                         found = true;
1077                                         break;
1078                                 }
1079                         }
1080                 }
1081                 spin_unlock_irq(&efivars->lock);
1082
1083                 if (!found) {
1084                         kfree(variable_name);
1085                         break;
1086                 } else
1087                         efivar_create_sysfs_entry(efivars,
1088                                                   variable_name_size,
1089                                                   variable_name, &vendor);
1090         }
1091 }
1092
1093 /*
1094  * Let's not leave out systab information that snuck into
1095  * the efivars driver
1096  */
1097 static ssize_t systab_show(struct kobject *kobj,
1098                            struct kobj_attribute *attr, char *buf)
1099 {
1100         char *str = buf;
1101
1102         if (!kobj || !buf)
1103                 return -EINVAL;
1104
1105         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1106                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1107         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1108                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1109         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1110                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1111         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1112                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1113         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1114                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1115         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1116                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1117         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1118                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1119
1120         return str - buf;
1121 }
1122
1123 static struct kobj_attribute efi_attr_systab =
1124                         __ATTR(systab, 0400, systab_show, NULL);
1125
1126 static struct attribute *efi_subsys_attrs[] = {
1127         &efi_attr_systab.attr,
1128         NULL,   /* maybe more in the future? */
1129 };
1130
1131 static struct attribute_group efi_subsys_attr_group = {
1132         .attrs = efi_subsys_attrs,
1133 };
1134
1135 static struct kobject *efi_kobj;
1136
1137 /*
1138  * efivar_create_sysfs_entry()
1139  * Requires:
1140  *    variable_name_size = number of bytes required to hold
1141  *                         variable_name (not counting the NULL
1142  *                         character at the end.
1143  *    efivars->lock is not held on entry or exit.
1144  * Returns 1 on failure, 0 on success
1145  */
1146 static int
1147 efivar_create_sysfs_entry(struct efivars *efivars,
1148                           unsigned long variable_name_size,
1149                           efi_char16_t *variable_name,
1150                           efi_guid_t *vendor_guid)
1151 {
1152         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1153         char *short_name;
1154         struct efivar_entry *new_efivar;
1155
1156         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1157         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1158
1159         if (!short_name || !new_efivar)  {
1160                 kfree(short_name);
1161                 kfree(new_efivar);
1162                 return 1;
1163         }
1164
1165         new_efivar->efivars = efivars;
1166         memcpy(new_efivar->var.VariableName, variable_name,
1167                 variable_name_size);
1168         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1169
1170         /* Convert Unicode to normal chars (assume top bits are 0),
1171            ala UTF-8 */
1172         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1173                 short_name[i] = variable_name[i] & 0xFF;
1174         }
1175         /* This is ugly, but necessary to separate one vendor's
1176            private variables from another's.         */
1177
1178         *(short_name + strlen(short_name)) = '-';
1179         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1180
1181         new_efivar->kobj.kset = efivars->kset;
1182         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1183                                  "%s", short_name);
1184         if (i) {
1185                 kfree(short_name);
1186                 kfree(new_efivar);
1187                 return 1;
1188         }
1189
1190         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1191         kfree(short_name);
1192         short_name = NULL;
1193
1194         spin_lock_irq(&efivars->lock);
1195         list_add(&new_efivar->list, &efivars->list);
1196         spin_unlock_irq(&efivars->lock);
1197
1198         return 0;
1199 }
1200
1201 static int
1202 create_efivars_bin_attributes(struct efivars *efivars)
1203 {
1204         struct bin_attribute *attr;
1205         int error;
1206
1207         /* new_var */
1208         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1209         if (!attr)
1210                 return -ENOMEM;
1211
1212         attr->attr.name = "new_var";
1213         attr->attr.mode = 0200;
1214         attr->write = efivar_create;
1215         attr->private = efivars;
1216         efivars->new_var = attr;
1217
1218         /* del_var */
1219         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1220         if (!attr) {
1221                 error = -ENOMEM;
1222                 goto out_free;
1223         }
1224         attr->attr.name = "del_var";
1225         attr->attr.mode = 0200;
1226         attr->write = efivar_delete;
1227         attr->private = efivars;
1228         efivars->del_var = attr;
1229
1230         sysfs_bin_attr_init(efivars->new_var);
1231         sysfs_bin_attr_init(efivars->del_var);
1232
1233         /* Register */
1234         error = sysfs_create_bin_file(&efivars->kset->kobj,
1235                                       efivars->new_var);
1236         if (error) {
1237                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1238                         " due to error %d\n", error);
1239                 goto out_free;
1240         }
1241         error = sysfs_create_bin_file(&efivars->kset->kobj,
1242                                       efivars->del_var);
1243         if (error) {
1244                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1245                         " due to error %d\n", error);
1246                 sysfs_remove_bin_file(&efivars->kset->kobj,
1247                                       efivars->new_var);
1248                 goto out_free;
1249         }
1250
1251         return 0;
1252 out_free:
1253         kfree(efivars->del_var);
1254         efivars->del_var = NULL;
1255         kfree(efivars->new_var);
1256         efivars->new_var = NULL;
1257         return error;
1258 }
1259
1260 void unregister_efivars(struct efivars *efivars)
1261 {
1262         struct efivar_entry *entry, *n;
1263
1264         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1265                 spin_lock_irq(&efivars->lock);
1266                 list_del(&entry->list);
1267                 spin_unlock_irq(&efivars->lock);
1268                 efivar_unregister(entry);
1269         }
1270         if (efivars->new_var)
1271                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1272         if (efivars->del_var)
1273                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1274         kfree(efivars->new_var);
1275         kfree(efivars->del_var);
1276         kset_unregister(efivars->kset);
1277 }
1278 EXPORT_SYMBOL_GPL(unregister_efivars);
1279
1280 int register_efivars(struct efivars *efivars,
1281                      const struct efivar_operations *ops,
1282                      struct kobject *parent_kobj)
1283 {
1284         efi_status_t status = EFI_NOT_FOUND;
1285         efi_guid_t vendor_guid;
1286         efi_char16_t *variable_name;
1287         unsigned long variable_name_size = 1024;
1288         int error = 0;
1289
1290         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1291         if (!variable_name) {
1292                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1293                 return -ENOMEM;
1294         }
1295
1296         spin_lock_init(&efivars->lock);
1297         INIT_LIST_HEAD(&efivars->list);
1298         efivars->ops = ops;
1299
1300         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1301         if (!efivars->kset) {
1302                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1303                 error = -ENOMEM;
1304                 goto out;
1305         }
1306
1307         /*
1308          * Per EFI spec, the maximum storage allocated for both
1309          * the variable name and variable data is 1024 bytes.
1310          */
1311
1312         do {
1313                 variable_name_size = 1024;
1314
1315                 status = ops->get_next_variable(&variable_name_size,
1316                                                 variable_name,
1317                                                 &vendor_guid);
1318                 switch (status) {
1319                 case EFI_SUCCESS:
1320                         efivar_create_sysfs_entry(efivars,
1321                                                   variable_name_size,
1322                                                   variable_name,
1323                                                   &vendor_guid);
1324                         break;
1325                 case EFI_NOT_FOUND:
1326                         break;
1327                 default:
1328                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1329                                 status);
1330                         status = EFI_NOT_FOUND;
1331                         break;
1332                 }
1333         } while (status != EFI_NOT_FOUND);
1334
1335         error = create_efivars_bin_attributes(efivars);
1336         if (error)
1337                 unregister_efivars(efivars);
1338
1339         if (!efivars_pstore_disable)
1340                 efivar_pstore_register(efivars);
1341
1342 out:
1343         kfree(variable_name);
1344
1345         return error;
1346 }
1347 EXPORT_SYMBOL_GPL(register_efivars);
1348
1349 static struct efivar_operations ops;
1350
1351 /*
1352  * For now we register the efi subsystem with the firmware subsystem
1353  * and the vars subsystem with the efi subsystem.  In the future, it
1354  * might make sense to split off the efi subsystem into its own
1355  * driver, but for now only efivars will register with it, so just
1356  * include it here.
1357  */
1358
1359 static int __init
1360 efivars_init(void)
1361 {
1362         int error = 0;
1363
1364         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1365                EFIVARS_DATE);
1366
1367         if (!efi_enabled(EFI_RUNTIME_SERVICES))
1368                 return 0;
1369
1370         /* For now we'll register the efi directory at /sys/firmware/efi */
1371         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1372         if (!efi_kobj) {
1373                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1374                 return -ENOMEM;
1375         }
1376
1377         ops.get_variable = efi.get_variable;
1378         ops.set_variable = efi.set_variable;
1379         ops.get_next_variable = efi.get_next_variable;
1380         ops.query_variable_info = efi.query_variable_info;
1381         error = register_efivars(&__efivars, &ops, efi_kobj);
1382         if (error)
1383                 goto err_put;
1384
1385         /* Don't forget the systab entry */
1386         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1387         if (error) {
1388                 printk(KERN_ERR
1389                        "efivars: Sysfs attribute export failed with error %d.\n",
1390                        error);
1391                 goto err_unregister;
1392         }
1393
1394         return 0;
1395
1396 err_unregister:
1397         unregister_efivars(&__efivars);
1398 err_put:
1399         kobject_put(efi_kobj);
1400         return error;
1401 }
1402
1403 static void __exit
1404 efivars_exit(void)
1405 {
1406         cancel_work_sync(&efivar_work);
1407
1408         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1409                 unregister_efivars(&__efivars);
1410                 kobject_put(efi_kobj);
1411         }
1412 }
1413
1414 module_init(efivars_init);
1415 module_exit(efivars_exit);
1416