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