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 int efi_status_to_err(efi_status_t status)
 657 {
 658         int err;
 659
 660         switch (status) {
 661         case EFI_INVALID_PARAMETER:
 662                 err = -EINVAL;
 663                 break;
 664         case EFI_OUT_OF_RESOURCES:
 665                 err = -ENOSPC;
 666                 break;
 667         case EFI_DEVICE_ERROR:
 668                 err = -EIO;
 669                 break;
 670         case EFI_WRITE_PROTECTED:
 671                 err = -EROFS;
 672                 break;
 673         case EFI_SECURITY_VIOLATION:
 674                 err = -EACCES;
 675                 break;
 676         case EFI_NOT_FOUND:
 677                 err = -ENOENT;
 678                 break;
 679         default:
 680                 err = -EINVAL;
 681         }
 682
 683         return err;
 684 }
 685
 686 static ssize_t efivarfs_file_write(struct file *file,
 687                 const char __user *userbuf, size_t count, loff_t *ppos)
 688 {
 689         struct efivar_entry *var = file->private_data;
 690         struct efivars *efivars;
 691         efi_status_t status;
 692         void *data;
 693         u32 attributes;
 694         struct inode *inode = file->f_mapping->host;
 695         unsigned long datasize = count - sizeof(attributes);
 696         unsigned long newdatasize;
 697         u64 storage_size, remaining_size, max_size;
 698         ssize_t bytes = 0;
 699
 700         if (count < sizeof(attributes))
 701                 return -EINVAL;
 702
 703         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 704                 return -EFAULT;
 705
 706         if (attributes & ~(EFI_VARIABLE_MASK))
 707                 return -EINVAL;
 708
 709         efivars = var->efivars;
 710
 711         /*
 712          * Ensure that the user can't allocate arbitrarily large
 713          * amounts of memory. Pick a default size of 64K if
 714          * QueryVariableInfo() isn't supported by the firmware.
 715          */
 716         spin_lock(&efivars->lock);
 717
 718         if (!efivars->ops->query_variable_info)
 719                 status = EFI_UNSUPPORTED;
 720         else {
 721                 const struct efivar_operations *fops = efivars->ops;
 722                 status = fops->query_variable_info(attributes, &storage_size,
 723                                                    &remaining_size, &max_size);
 724         }
 725
 726         spin_unlock(&efivars->lock);
 727
 728         if (status != EFI_SUCCESS) {
 729                 if (status != EFI_UNSUPPORTED)
 730                         return efi_status_to_err(status);
 731
 732                 remaining_size = 65536;
 733         }
 734
 735         if (datasize > remaining_size)
 736                 return -ENOSPC;
 737
 738         data = kmalloc(datasize, GFP_KERNEL);
 739         if (!data)
 740                 return -ENOMEM;
 741
 742         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 743                 bytes = -EFAULT;
 744                 goto out;
 745         }
 746
 747         if (validate_var(&var->var, data, datasize) == false) {
 748                 bytes = -EINVAL;
 749                 goto out;
 750         }
 751
 752         /*
 753          * The lock here protects the get_variable call, the conditional
 754          * set_variable call, and removal of the variable from the efivars
 755          * list (in the case of an authenticated delete).
 756          */
 757         spin_lock(&efivars->lock);
 758
 759         status = efivars->ops->set_variable(var->var.VariableName,
 760                                             &var->var.VendorGuid,
 761                                             attributes, datasize,
 762                                             data);
 763
 764         if (status != EFI_SUCCESS) {
 765                 spin_unlock(&efivars->lock);
 766                 kfree(data);
 767
 768                 return efi_status_to_err(status);
 769         }
 770
 771         bytes = count;
 772
 773         /*
 774          * Writing to the variable may have caused a change in size (which
 775          * could either be an append or an overwrite), or the variable to be
 776          * deleted. Perform a GetVariable() so we can tell what actually
 777          * happened.
 778          */
 779         newdatasize = 0;
 780         status = efivars->ops->get_variable(var->var.VariableName,
 781                                             &var->var.VendorGuid,
 782                                             NULL, &newdatasize,
 783                                             NULL);
 784
 785         if (status == EFI_BUFFER_TOO_SMALL) {
 786                 spin_unlock(&efivars->lock);
 787                 mutex_lock(&inode->i_mutex);
 788                 i_size_write(inode, newdatasize + sizeof(attributes));
 789                 mutex_unlock(&inode->i_mutex);
 790
 791         } else if (status == EFI_NOT_FOUND) {
 792                 list_del(&var->list);
 793                 spin_unlock(&efivars->lock);
 794                 efivar_unregister(var);
 795                 drop_nlink(inode);
 796                 dput(file->f_dentry);
 797
 798         } else {
 799                 spin_unlock(&efivars->lock);
 800                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
 801                                 "status = %lx\n", status);
 802         }
 803
 804 out:
 805         kfree(data);
 806
 807         return bytes;
 808 }
 809
 810 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 811                 size_t count, loff_t *ppos)
 812 {
 813         struct efivar_entry *var = file->private_data;
 814         struct efivars *efivars = var->efivars;
 815         efi_status_t status;
 816         unsigned long datasize = 0;
 817         u32 attributes;
 818         void *data;
 819         ssize_t size = 0;
 820
 821         spin_lock(&efivars->lock);
 822         status = efivars->ops->get_variable(var->var.VariableName,
 823                                             &var->var.VendorGuid,
 824                                             &attributes, &datasize, NULL);
 825         spin_unlock(&efivars->lock);
 826
 827         if (status != EFI_BUFFER_TOO_SMALL)
 828                 return efi_status_to_err(status);
 829
 830         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 831
 832         if (!data)
 833                 return -ENOMEM;
 834
 835         spin_lock(&efivars->lock);
 836         status = efivars->ops->get_variable(var->var.VariableName,
 837                                             &var->var.VendorGuid,
 838                                             &attributes, &datasize,
 839                                             (data + sizeof(attributes)));
 840         spin_unlock(&efivars->lock);
 841
 842         if (status != EFI_SUCCESS) {
 843                 size = efi_status_to_err(status);
 844                 goto out_free;
 845         }
 846
 847         memcpy(data, &attributes, sizeof(attributes));
 848         size = simple_read_from_buffer(userbuf, count, ppos,
 849                                        data, datasize + sizeof(attributes));
 850 out_free:
 851         kfree(data);
 852
 853         return size;
 854 }
 855
 856 static void efivarfs_evict_inode(struct inode *inode)
 857 {
 858         clear_inode(inode);
 859 }
 860
 861 static const struct super_operations efivarfs_ops = {
 862         .statfs = simple_statfs,
 863         .drop_inode = generic_delete_inode,
 864         .evict_inode = efivarfs_evict_inode,
 865         .show_options = generic_show_options,
 866 };
 867
 868 static struct super_block *efivarfs_sb;
 869
 870 static const struct inode_operations efivarfs_dir_inode_operations;
 871
 872 static const struct file_operations efivarfs_file_operations = {
 873         .open   = efivarfs_file_open,
 874         .read   = efivarfs_file_read,
 875         .write  = efivarfs_file_write,
 876         .llseek = no_llseek,
 877 };
 878
 879 static struct inode *efivarfs_get_inode(struct super_block *sb,
 880                                 const struct inode *dir, int mode, dev_t dev)
 881 {
 882         struct inode *inode = new_inode(sb);
 883
 884         if (inode) {
 885                 inode->i_ino = get_next_ino();
 886                 inode->i_mode = mode;
 887                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 888                 switch (mode & S_IFMT) {
 889                 case S_IFREG:
 890                         inode->i_fop = &efivarfs_file_operations;
 891                         break;
 892                 case S_IFDIR:
 893                         inode->i_op = &efivarfs_dir_inode_operations;
 894                         inode->i_fop = &simple_dir_operations;
 895                         inc_nlink(inode);
 896                         break;
 897                 }
 898         }
 899         return inode;
 900 }
 901
 902 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
 903 {
 904         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
 905         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
 906         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
 907         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
 908         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
 909         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
 910         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
 911         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
 912         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
 913         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
 914         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
 915         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
 916         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
 917         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
 918         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
 919         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
 920 }
 921
 922 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 923                           umode_t mode, bool excl)
 924 {
 925         struct inode *inode;
 926         struct efivars *efivars = &__efivars;
 927         struct efivar_entry *var;
 928         int namelen, i = 0, err = 0;
 929
 930         /*
 931          * We need a GUID, plus at least one letter for the variable name,
 932          * plus the '-' separator
 933          */
 934         if (dentry->d_name.len < GUID_LEN + 2)
 935                 return -EINVAL;
 936
 937         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
 938         if (!inode)
 939                 return -ENOMEM;
 940
 941         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 942         if (!var) {
 943                 err = -ENOMEM;
 944                 goto out;
 945         }
 946
 947         /* length of the variable name itself: remove GUID and separator */
 948         namelen = dentry->d_name.len - GUID_LEN - 1;
 949
 950         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
 951                         &var->var.VendorGuid);
 952
 953         for (i = 0; i < namelen; i++)
 954                 var->var.VariableName[i] = dentry->d_name.name[i];
 955
 956         var->var.VariableName[i] = '\0';
 957
 958         inode->i_private = var;
 959         var->efivars = efivars;
 960         var->kobj.kset = efivars->kset;
 961
 962         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
 963                              dentry->d_name.name);
 964         if (err)
 965                 goto out;
 966
 967         kobject_uevent(&var->kobj, KOBJ_ADD);
 968         spin_lock(&efivars->lock);
 969         list_add(&var->list, &efivars->list);
 970         spin_unlock(&efivars->lock);
 971         d_instantiate(dentry, inode);
 972         dget(dentry);
 973 out:
 974         if (err) {
 975                 kfree(var);
 976                 iput(inode);
 977         }
 978         return err;
 979 }
 980
 981 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
 982 {
 983         struct efivar_entry *var = dentry->d_inode->i_private;
 984         struct efivars *efivars = var->efivars;
 985         efi_status_t status;
 986
 987         spin_lock(&efivars->lock);
 988
 989         status = efivars->ops->set_variable(var->var.VariableName,
 990                                             &var->var.VendorGuid,
 991                                             0, 0, NULL);
 992
 993         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
 994                 list_del(&var->list);
 995                 spin_unlock(&efivars->lock);
 996                 efivar_unregister(var);
 997                 drop_nlink(dir);
 998                 dput(dentry);
 999                 return 0;
1000         }
1001
1002         spin_unlock(&efivars->lock);
1003         return -EINVAL;
1004 };
1005
1006 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1007 {
1008         struct inode *inode = NULL;
1009         struct dentry *root;
1010         struct efivar_entry *entry, *n;
1011         struct efivars *efivars = &__efivars;
1012         char *name;
1013
1014         efivarfs_sb = sb;
1015
1016         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1017         sb->s_blocksize         = PAGE_CACHE_SIZE;
1018         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1019         sb->s_magic             = EFIVARFS_MAGIC;
1020         sb->s_op                = &efivarfs_ops;
1021         sb->s_time_gran         = 1;
1022
1023         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1024         if (!inode)
1025                 return -ENOMEM;
1026         inode->i_op = &efivarfs_dir_inode_operations;
1027
1028         root = d_make_root(inode);
1029         sb->s_root = root;
1030         if (!root)
1031                 return -ENOMEM;
1032
1033         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1034                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1035                 unsigned long size = 0;
1036                 int len, i;
1037
1038                 inode = NULL;
1039
1040                 len = utf16_strlen(entry->var.VariableName);
1041
1042                 /* name, plus '-', plus GUID, plus NUL*/
1043                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1044                 if (!name)
1045                         goto fail;
1046
1047                 for (i = 0; i < len; i++)
1048                         name[i] = entry->var.VariableName[i] & 0xFF;
1049
1050                 name[len] = '-';
1051
1052                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1053
1054                 name[len+GUID_LEN+1] = '\0';
1055
1056                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1057                                           S_IFREG | 0644, 0);
1058                 if (!inode)
1059                         goto fail_name;
1060
1061                 dentry = d_alloc_name(root, name);
1062                 if (!dentry)
1063                         goto fail_inode;
1064
1065                 /* copied by the above to local storage in the dentry. */
1066                 kfree(name);
1067
1068                 spin_lock(&efivars->lock);
1069                 efivars->ops->get_variable(entry->var.VariableName,
1070                                            &entry->var.VendorGuid,
1071                                            &entry->var.Attributes,
1072                                            &size,
1073                                            NULL);
1074                 spin_unlock(&efivars->lock);
1075
1076                 mutex_lock(&inode->i_mutex);
1077                 inode->i_private = entry;
1078                 i_size_write(inode, size+4);
1079                 mutex_unlock(&inode->i_mutex);
1080                 d_add(dentry, inode);
1081         }
1082
1083         return 0;
1084
1085 fail_inode:
1086         iput(inode);
1087 fail_name:
1088         kfree(name);
1089 fail:
1090         return -ENOMEM;
1091 }
1092
1093 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1094                                     int flags, const char *dev_name, void *data)
1095 {
1096         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1097 }
1098
1099 static void efivarfs_kill_sb(struct super_block *sb)
1100 {
1101         kill_litter_super(sb);
1102         efivarfs_sb = NULL;
1103 }
1104
1105 static struct file_system_type efivarfs_type = {
1106         .name    = "efivarfs",
1107         .mount   = efivarfs_mount,
1108         .kill_sb = efivarfs_kill_sb,
1109 };
1110
1111 static const struct inode_operations efivarfs_dir_inode_operations = {
1112         .lookup = simple_lookup,
1113         .unlink = efivarfs_unlink,
1114         .create = efivarfs_create,
1115 };
1116
1117 static struct pstore_info efi_pstore_info;
1118
1119 #ifdef CONFIG_PSTORE
1120
1121 static int efi_pstore_open(struct pstore_info *psi)
1122 {
1123         struct efivars *efivars = psi->data;
1124
1125         spin_lock(&efivars->lock);
1126         efivars->walk_entry = list_first_entry(&efivars->list,
1127                                                struct efivar_entry, list);
1128         return 0;
1129 }
1130
1131 static int efi_pstore_close(struct pstore_info *psi)
1132 {
1133         struct efivars *efivars = psi->data;
1134
1135         spin_unlock(&efivars->lock);
1136         return 0;
1137 }
1138
1139 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1140                                int *count, struct timespec *timespec,
1141                                char **buf, struct pstore_info *psi)
1142 {
1143         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1144         struct efivars *efivars = psi->data;
1145         char name[DUMP_NAME_LEN];
1146         int i;
1147         int cnt;
1148         unsigned int part, size;
1149         unsigned long time;
1150
1151         while (&efivars->walk_entry->list != &efivars->list) {
1152                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1153                                  vendor)) {
1154                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1155                                 name[i] = efivars->walk_entry->var.VariableName[i];
1156                         }
1157                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1158                                    type, &part, &cnt, &time) == 4) {
1159                                 *id = part;
1160                                 *count = cnt;
1161                                 timespec->tv_sec = time;
1162                                 timespec->tv_nsec = 0;
1163                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1164                                    type, &part, &time) == 3) {
1165                                 /*
1166                                  * Check if an old format,
1167                                  * which doesn't support holding
1168                                  * multiple logs, remains.
1169                                  */
1170                                 *id = part;
1171                                 *count = 0;
1172                                 timespec->tv_sec = time;
1173                                 timespec->tv_nsec = 0;
1174                         } else {
1175                                 efivars->walk_entry = list_entry(
1176                                                 efivars->walk_entry->list.next,
1177                                                 struct efivar_entry, list);
1178                                 continue;
1179                         }
1180
1181                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1182                         size = efivars->walk_entry->var.DataSize;
1183                         *buf = kmalloc(size, GFP_KERNEL);
1184                         if (*buf == NULL)
1185                                 return -ENOMEM;
1186                         memcpy(*buf, efivars->walk_entry->var.Data,
1187                                size);
1188                         efivars->walk_entry = list_entry(
1189                                         efivars->walk_entry->list.next,
1190                                         struct efivar_entry, list);
1191                         return size;
1192                 }
1193                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1194                                                  struct efivar_entry, list);
1195         }
1196         return 0;
1197 }
1198
1199 static int efi_pstore_write(enum pstore_type_id type,
1200                 enum kmsg_dump_reason reason, u64 *id,
1201                 unsigned int part, int count, size_t size,
1202                 struct pstore_info *psi)
1203 {
1204         char name[DUMP_NAME_LEN];
1205         efi_char16_t efi_name[DUMP_NAME_LEN];
1206         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1207         struct efivars *efivars = psi->data;
1208         int i, ret = 0;
1209         u64 storage_space, remaining_space, max_variable_size;
1210         efi_status_t status = EFI_NOT_FOUND;
1211
1212         spin_lock(&efivars->lock);
1213
1214         /*
1215          * Check if there is a space enough to log.
1216          * size: a size of logging data
1217          * DUMP_NAME_LEN * 2: a maximum size of variable name
1218          */
1219         status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
1220                                                    &storage_space,
1221                                                    &remaining_space,
1222                                                    &max_variable_size);
1223         if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
1224                 spin_unlock(&efivars->lock);
1225                 *id = part;
1226                 return -ENOSPC;
1227         }
1228
1229         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1230                 get_seconds());
1231
1232         for (i = 0; i < DUMP_NAME_LEN; i++)
1233                 efi_name[i] = name[i];
1234
1235         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1236                                    size, psi->buf);
1237
1238         spin_unlock(&efivars->lock);
1239
1240         if (size)
1241                 ret = efivar_create_sysfs_entry(efivars,
1242                                           utf16_strsize(efi_name,
1243                                                         DUMP_NAME_LEN * 2),
1244                                           efi_name, &vendor);
1245
1246         *id = part;
1247         return ret;
1248 };
1249
1250 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1251                             struct timespec time, struct pstore_info *psi)
1252 {
1253         char name[DUMP_NAME_LEN];
1254         efi_char16_t efi_name[DUMP_NAME_LEN];
1255         char name_old[DUMP_NAME_LEN];
1256         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1257         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1258         struct efivars *efivars = psi->data;
1259         struct efivar_entry *entry, *found = NULL;
1260         int i;
1261
1262         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1263                 time.tv_sec);
1264
1265         spin_lock(&efivars->lock);
1266
1267         for (i = 0; i < DUMP_NAME_LEN; i++)
1268                 efi_name[i] = name[i];
1269
1270         /*
1271          * Clean up an entry with the same name
1272          */
1273
1274         list_for_each_entry(entry, &efivars->list, list) {
1275                 get_var_data_locked(efivars, &entry->var);
1276
1277                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1278                         continue;
1279                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1280                                   utf16_strlen(efi_name))) {
1281                         /*
1282                          * Check if an old format,
1283                          * which doesn't support holding
1284                          * multiple logs, remains.
1285                          */
1286                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1287                                 (unsigned int)id, time.tv_sec);
1288
1289                         for (i = 0; i < DUMP_NAME_LEN; i++)
1290                                 efi_name_old[i] = name_old[i];
1291
1292                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1293                                           utf16_strlen(efi_name_old)))
1294                                 continue;
1295                 }
1296
1297                 /* found */
1298                 found = entry;
1299                 efivars->ops->set_variable(entry->var.VariableName,
1300                                            &entry->var.VendorGuid,
1301                                            PSTORE_EFI_ATTRIBUTES,
1302                                            0, NULL);
1303                 break;
1304         }
1305
1306         if (found)
1307                 list_del(&found->list);
1308
1309         spin_unlock(&efivars->lock);
1310
1311         if (found)
1312                 efivar_unregister(found);
1313
1314         return 0;
1315 }
1316 #else
1317 static int efi_pstore_open(struct pstore_info *psi)
1318 {
1319         return 0;
1320 }
1321
1322 static int efi_pstore_close(struct pstore_info *psi)
1323 {
1324         return 0;
1325 }
1326
1327 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1328                                struct timespec *timespec,
1329                                char **buf, struct pstore_info *psi)
1330 {
1331         return -1;
1332 }
1333
1334 static int efi_pstore_write(enum pstore_type_id type,
1335                 enum kmsg_dump_reason reason, u64 *id,
1336                 unsigned int part, int count, size_t size,
1337                 struct pstore_info *psi)
1338 {
1339         return 0;
1340 }
1341
1342 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1343                             struct timespec time, struct pstore_info *psi)
1344 {
1345         return 0;
1346 }
1347 #endif
1348
1349 static struct pstore_info efi_pstore_info = {
1350         .owner          = THIS_MODULE,
1351         .name           = "efi",
1352         .open           = efi_pstore_open,
1353         .close          = efi_pstore_close,
1354         .read           = efi_pstore_read,
1355         .write          = efi_pstore_write,
1356         .erase          = efi_pstore_erase,
1357 };
1358
1359 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1360                              struct bin_attribute *bin_attr,
1361                              char *buf, loff_t pos, size_t count)
1362 {
1363         struct efi_variable *new_var = (struct efi_variable *)buf;
1364         struct efivars *efivars = bin_attr->private;
1365         struct efivar_entry *search_efivar, *n;
1366         unsigned long strsize1, strsize2;
1367         efi_status_t status = EFI_NOT_FOUND;
1368         int found = 0;
1369
1370         if (!capable(CAP_SYS_ADMIN))
1371                 return -EACCES;
1372
1373         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1374             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1375                 printk(KERN_ERR "efivars: Malformed variable content\n");
1376                 return -EINVAL;
1377         }
1378
1379         spin_lock(&efivars->lock);
1380
1381         /*
1382          * Does this variable already exist?
1383          */
1384         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1385                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1386                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1387                 if (strsize1 == strsize2 &&
1388                         !memcmp(&(search_efivar->var.VariableName),
1389                                 new_var->VariableName, strsize1) &&
1390                         !efi_guidcmp(search_efivar->var.VendorGuid,
1391                                 new_var->VendorGuid)) {
1392                         found = 1;
1393                         break;
1394                 }
1395         }
1396         if (found) {
1397                 spin_unlock(&efivars->lock);
1398                 return -EINVAL;
1399         }
1400
1401         /* now *really* create the variable via EFI */
1402         status = efivars->ops->set_variable(new_var->VariableName,
1403                                             &new_var->VendorGuid,
1404                                             new_var->Attributes,
1405                                             new_var->DataSize,
1406                                             new_var->Data);
1407
1408         if (status != EFI_SUCCESS) {
1409                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1410                         status);
1411                 spin_unlock(&efivars->lock);
1412                 return -EIO;
1413         }
1414         spin_unlock(&efivars->lock);
1415
1416         /* Create the entry in sysfs.  Locking is not required here */
1417         status = efivar_create_sysfs_entry(efivars,
1418                                            utf16_strsize(new_var->VariableName,
1419                                                          1024),
1420                                            new_var->VariableName,
1421                                            &new_var->VendorGuid);
1422         if (status) {
1423                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1424         }
1425         return count;
1426 }
1427
1428 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1429                              struct bin_attribute *bin_attr,
1430                              char *buf, loff_t pos, size_t count)
1431 {
1432         struct efi_variable *del_var = (struct efi_variable *)buf;
1433         struct efivars *efivars = bin_attr->private;
1434         struct efivar_entry *search_efivar, *n;
1435         unsigned long strsize1, strsize2;
1436         efi_status_t status = EFI_NOT_FOUND;
1437         int found = 0;
1438
1439         if (!capable(CAP_SYS_ADMIN))
1440                 return -EACCES;
1441
1442         spin_lock(&efivars->lock);
1443
1444         /*
1445          * Does this variable already exist?
1446          */
1447         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1448                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1449                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1450                 if (strsize1 == strsize2 &&
1451                         !memcmp(&(search_efivar->var.VariableName),
1452                                 del_var->VariableName, strsize1) &&
1453                         !efi_guidcmp(search_efivar->var.VendorGuid,
1454                                 del_var->VendorGuid)) {
1455                         found = 1;
1456                         break;
1457                 }
1458         }
1459         if (!found) {
1460                 spin_unlock(&efivars->lock);
1461                 return -EINVAL;
1462         }
1463         /* force the Attributes/DataSize to 0 to ensure deletion */
1464         del_var->Attributes = 0;
1465         del_var->DataSize = 0;
1466
1467         status = efivars->ops->set_variable(del_var->VariableName,
1468                                             &del_var->VendorGuid,
1469                                             del_var->Attributes,
1470                                             del_var->DataSize,
1471                                             del_var->Data);
1472
1473         if (status != EFI_SUCCESS) {
1474                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1475                         status);
1476                 spin_unlock(&efivars->lock);
1477                 return -EIO;
1478         }
1479         list_del(&search_efivar->list);
1480         /* We need to release this lock before unregistering. */
1481         spin_unlock(&efivars->lock);
1482         efivar_unregister(search_efivar);
1483
1484         /* It's dead Jim.... */
1485         return count;
1486 }
1487
1488 /*
1489  * Let's not leave out systab information that snuck into
1490  * the efivars driver
1491  */
1492 static ssize_t systab_show(struct kobject *kobj,
1493                            struct kobj_attribute *attr, char *buf)
1494 {
1495         char *str = buf;
1496
1497         if (!kobj || !buf)
1498                 return -EINVAL;
1499
1500         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1501                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1502         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1503                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1504         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1505                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1506         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1507                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1508         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1509                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1510         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1511                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1512         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1513                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1514
1515         return str - buf;
1516 }
1517
1518 static struct kobj_attribute efi_attr_systab =
1519                         __ATTR(systab, 0400, systab_show, NULL);
1520
1521 static struct attribute *efi_subsys_attrs[] = {
1522         &efi_attr_systab.attr,
1523         NULL,   /* maybe more in the future? */
1524 };
1525
1526 static struct attribute_group efi_subsys_attr_group = {
1527         .attrs = efi_subsys_attrs,
1528 };
1529
1530 static struct kobject *efi_kobj;
1531
1532 /*
1533  * efivar_create_sysfs_entry()
1534  * Requires:
1535  *    variable_name_size = number of bytes required to hold
1536  *                         variable_name (not counting the NULL
1537  *                         character at the end.
1538  *    efivars->lock is not held on entry or exit.
1539  * Returns 1 on failure, 0 on success
1540  */
1541 static int
1542 efivar_create_sysfs_entry(struct efivars *efivars,
1543                           unsigned long variable_name_size,
1544                           efi_char16_t *variable_name,
1545                           efi_guid_t *vendor_guid)
1546 {
1547         int i, short_name_size;
1548         char *short_name;
1549         struct efivar_entry *new_efivar;
1550
1551         /*
1552          * Length of the variable bytes in ASCII, plus the '-' separator,
1553          * plus the GUID, plus trailing NUL
1554          */
1555         short_name_size = variable_name_size / sizeof(efi_char16_t)
1556                                 + 1 + GUID_LEN + 1;
1557
1558         short_name = kzalloc(short_name_size, GFP_KERNEL);
1559         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1560
1561         if (!short_name || !new_efivar)  {
1562                 kfree(short_name);
1563                 kfree(new_efivar);
1564                 return 1;
1565         }
1566
1567         new_efivar->efivars = efivars;
1568         memcpy(new_efivar->var.VariableName, variable_name,
1569                 variable_name_size);
1570         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1571
1572         /* Convert Unicode to normal chars (assume top bits are 0),
1573            ala UTF-8 */
1574         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1575                 short_name[i] = variable_name[i] & 0xFF;
1576         }
1577         /* This is ugly, but necessary to separate one vendor's
1578            private variables from another's.         */
1579
1580         *(short_name + strlen(short_name)) = '-';
1581         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1582
1583         new_efivar->kobj.kset = efivars->kset;
1584         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1585                                  "%s", short_name);
1586         if (i) {
1587                 kfree(short_name);
1588                 kfree(new_efivar);
1589                 return 1;
1590         }
1591
1592         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1593         kfree(short_name);
1594         short_name = NULL;
1595
1596         spin_lock(&efivars->lock);
1597         list_add(&new_efivar->list, &efivars->list);
1598         spin_unlock(&efivars->lock);
1599
1600         return 0;
1601 }
1602
1603 static int
1604 create_efivars_bin_attributes(struct efivars *efivars)
1605 {
1606         struct bin_attribute *attr;
1607         int error;
1608
1609         /* new_var */
1610         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1611         if (!attr)
1612                 return -ENOMEM;
1613
1614         attr->attr.name = "new_var";
1615         attr->attr.mode = 0200;
1616         attr->write = efivar_create;
1617         attr->private = efivars;
1618         efivars->new_var = attr;
1619
1620         /* del_var */
1621         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1622         if (!attr) {
1623                 error = -ENOMEM;
1624                 goto out_free;
1625         }
1626         attr->attr.name = "del_var";
1627         attr->attr.mode = 0200;
1628         attr->write = efivar_delete;
1629         attr->private = efivars;
1630         efivars->del_var = attr;
1631
1632         sysfs_bin_attr_init(efivars->new_var);
1633         sysfs_bin_attr_init(efivars->del_var);
1634
1635         /* Register */
1636         error = sysfs_create_bin_file(&efivars->kset->kobj,
1637                                       efivars->new_var);
1638         if (error) {
1639                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1640                         " due to error %d\n", error);
1641                 goto out_free;
1642         }
1643         error = sysfs_create_bin_file(&efivars->kset->kobj,
1644                                       efivars->del_var);
1645         if (error) {
1646                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1647                         " due to error %d\n", error);
1648                 sysfs_remove_bin_file(&efivars->kset->kobj,
1649                                       efivars->new_var);
1650                 goto out_free;
1651         }
1652
1653         return 0;
1654 out_free:
1655         kfree(efivars->del_var);
1656         efivars->del_var = NULL;
1657         kfree(efivars->new_var);
1658         efivars->new_var = NULL;
1659         return error;
1660 }
1661
1662 void unregister_efivars(struct efivars *efivars)
1663 {
1664         struct efivar_entry *entry, *n;
1665
1666         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1667                 spin_lock(&efivars->lock);
1668                 list_del(&entry->list);
1669                 spin_unlock(&efivars->lock);
1670                 efivar_unregister(entry);
1671         }
1672         if (efivars->new_var)
1673                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1674         if (efivars->del_var)
1675                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1676         kfree(efivars->new_var);
1677         kfree(efivars->del_var);
1678         kobject_put(efivars->kobject);
1679         kset_unregister(efivars->kset);
1680 }
1681 EXPORT_SYMBOL_GPL(unregister_efivars);
1682
1683 int register_efivars(struct efivars *efivars,
1684                      const struct efivar_operations *ops,
1685                      struct kobject *parent_kobj)
1686 {
1687         efi_status_t status = EFI_NOT_FOUND;
1688         efi_guid_t vendor_guid;
1689         efi_char16_t *variable_name;
1690         unsigned long variable_name_size = 1024;
1691         int error = 0;
1692
1693         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1694         if (!variable_name) {
1695                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1696                 return -ENOMEM;
1697         }
1698
1699         spin_lock_init(&efivars->lock);
1700         INIT_LIST_HEAD(&efivars->list);
1701         efivars->ops = ops;
1702
1703         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1704         if (!efivars->kset) {
1705                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1706                 error = -ENOMEM;
1707                 goto out;
1708         }
1709
1710         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1711         if (!efivars->kobject) {
1712                 pr_err("efivars: Subsystem registration failed.\n");
1713                 error = -ENOMEM;
1714                 kset_unregister(efivars->kset);
1715                 goto out;
1716         }
1717
1718         /*
1719          * Per EFI spec, the maximum storage allocated for both
1720          * the variable name and variable data is 1024 bytes.
1721          */
1722
1723         do {
1724                 variable_name_size = 1024;
1725
1726                 status = ops->get_next_variable(&variable_name_size,
1727                                                 variable_name,
1728                                                 &vendor_guid);
1729                 switch (status) {
1730                 case EFI_SUCCESS:
1731                         efivar_create_sysfs_entry(efivars,
1732                                                   variable_name_size,
1733                                                   variable_name,
1734                                                   &vendor_guid);
1735                         break;
1736                 case EFI_NOT_FOUND:
1737                         break;
1738                 default:
1739                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1740                                 status);
1741                         status = EFI_NOT_FOUND;
1742                         break;
1743                 }
1744         } while (status != EFI_NOT_FOUND);
1745
1746         error = create_efivars_bin_attributes(efivars);
1747         if (error)
1748                 unregister_efivars(efivars);
1749
1750         efivars->efi_pstore_info = efi_pstore_info;
1751
1752         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1753         if (efivars->efi_pstore_info.buf) {
1754                 efivars->efi_pstore_info.bufsize = 1024;
1755                 efivars->efi_pstore_info.data = efivars;
1756                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1757                 pstore_register(&efivars->efi_pstore_info);
1758         }
1759
1760         register_filesystem(&efivarfs_type);
1761
1762 out:
1763         kfree(variable_name);
1764
1765         return error;
1766 }
1767 EXPORT_SYMBOL_GPL(register_efivars);
1768
1769 /*
1770  * For now we register the efi subsystem with the firmware subsystem
1771  * and the vars subsystem with the efi subsystem.  In the future, it
1772  * might make sense to split off the efi subsystem into its own
1773  * driver, but for now only efivars will register with it, so just
1774  * include it here.
1775  */
1776
1777 static int __init
1778 efivars_init(void)
1779 {
1780         int error = 0;
1781
1782         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1783                EFIVARS_DATE);
1784
1785         if (!efi_enabled)
1786                 return 0;
1787
1788         /* For now we'll register the efi directory at /sys/firmware/efi */
1789         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1790         if (!efi_kobj) {
1791                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1792                 return -ENOMEM;
1793         }
1794
1795         ops.get_variable = efi.get_variable;
1796         ops.set_variable = efi.set_variable;
1797         ops.get_next_variable = efi.get_next_variable;
1798         ops.query_variable_info = efi.query_variable_info;
1799
1800         error = register_efivars(&__efivars, &ops, efi_kobj);
1801         if (error)
1802                 goto err_put;
1803
1804         /* Don't forget the systab entry */
1805         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1806         if (error) {
1807                 printk(KERN_ERR
1808                        "efivars: Sysfs attribute export failed with error %d.\n",
1809                        error);
1810                 goto err_unregister;
1811         }
1812
1813         return 0;
1814
1815 err_unregister:
1816         unregister_efivars(&__efivars);
1817 err_put:
1818         kobject_put(efi_kobj);
1819         return error;
1820 }
1821
1822 static void __exit
1823 efivars_exit(void)
1824 {
1825         if (efi_enabled) {
1826                 unregister_efivars(&__efivars);
1827                 kobject_put(efi_kobj);
1828         }
1829 }
1830
1831 module_init(efivars_init);
1832 module_exit(efivars_exit);
1833