drivers/firmware/efivars.c

   1 /*
   2  * EFI Variables - efivars.c
   3  *
   4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
   5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
   6  *
   7  * This code takes all variables accessible from EFI runtime and
   8  *  exports them via sysfs
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  * Changelog:
  25  *
  26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
  27  *   remove check for efi_enabled in exit
  28  *   add MODULE_VERSION
  29  *
  30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
  31  *   minor bug fixes
  32  *
  33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
  34  *   converted driver to export variable information via sysfs
  35  *   and moved to drivers/firmware directory
  36  *   bumped revision number to v0.07 to reflect conversion & move
  37  *
  38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
  39  *   fix locking per Peter Chubb's findings
  40  *
  41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
  42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
  43  *
  44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
  45  *   use list_for_each_safe when deleting vars.
  46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
  47  *   v0.04 release to linux-ia64@linuxia64.org
  48  *
  49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
  50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
  51  *   efi.c own the /proc/efi directory.
  52  *   v0.03 release to linux-ia64@linuxia64.org
  53  *
  54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  55  *   At the request of Stephane, moved ownership of /proc/efi
  56  *   to efi.c, and now efivars lives under /proc/efi/vars.
  57  *
  58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  59  *   Feedback received from Stephane Eranian incorporated.
  60  *   efivar_write() checks copy_from_user() return value.
  61  *   efivar_read/write() returns proper errno.
  62  *   v0.02 release to linux-ia64@linuxia64.org
  63  *
  64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
  65  *   v0.01 release to linux-ia64@linuxia64.org
  66  */
  67
  68 #include <linux/capability.h>
  69 #include <linux/types.h>
  70 #include <linux/errno.h>
  71 #include <linux/init.h>
  72 #include <linux/mm.h>
  73 #include <linux/module.h>
  74 #include <linux/string.h>
  75 #include <linux/smp.h>
  76 #include <linux/efi.h>
  77 #include <linux/sysfs.h>
  78 #include <linux/kobject.h>
  79 #include <linux/device.h>
  80 #include <linux/slab.h>
  81 #include <linux/pstore.h>
  82 #include <linux/ctype.h>
  83
  84 #include <linux/fs.h>
  85 #include <linux/ramfs.h>
  86 #include <linux/pagemap.h>
  87
  88 #include <asm/uaccess.h>
  89
  90 #define EFIVARS_VERSION "0.08"
  91 #define EFIVARS_DATE "2004-May-17"
  92
  93 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  94 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  95 MODULE_LICENSE("GPL");
  96 MODULE_VERSION(EFIVARS_VERSION);
  97
  98 #define DUMP_NAME_LEN 52
  99
 100 /*
 101  * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
 102  * not including trailing NUL
 103  */
 104 #define GUID_LEN 36
 105
 106 /*
 107  * The maximum size of VariableName + Data = 1024
 108  * Therefore, it's reasonable to save that much
 109  * space in each part of the structure,
 110  * and we use a page for reading/writing.
 111  */
 112
 113 struct efi_variable {
 114         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 115         efi_guid_t    VendorGuid;
 116         unsigned long DataSize;
 117         __u8          Data[1024];
 118         efi_status_t  Status;
 119         __u32         Attributes;
 120 } __attribute__((packed));
 121
 122 struct efivar_entry {
 123         struct efivars *efivars;
 124         struct efi_variable var;
 125         struct list_head list;
 126         struct kobject kobj;
 127 };
 128
 129 struct efivar_attribute {
 130         struct attribute attr;
 131         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 132         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 133 };
 134
 135 static struct efivars __efivars;
 136 static struct efivar_operations ops;
 137
 138 #define PSTORE_EFI_ATTRIBUTES \
 139         (EFI_VARIABLE_NON_VOLATILE | \
 140          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 141          EFI_VARIABLE_RUNTIME_ACCESS)
 142
 143 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 144 struct efivar_attribute efivar_attr_##_name = { \
 145         .attr = {.name = __stringify(_name), .mode = _mode}, \
 146         .show = _show, \
 147         .store = _store, \
 148 };
 149
 150 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 151 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 152
 153 /*
 154  * Prototype for sysfs creation function
 155  */
 156 static int
 157 efivar_create_sysfs_entry(struct efivars *efivars,
 158                           unsigned long variable_name_size,
 159                           efi_char16_t *variable_name,
 160                           efi_guid_t *vendor_guid);
 161
 162 /* Return the number of unicode characters in data */
 163 static unsigned long
 164 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 165 {
 166         unsigned long length = 0;
 167
 168         while (*s++ != 0 && length < maxlength)
 169                 length++;
 170         return length;
 171 }
 172
 173 static inline unsigned long
 174 utf16_strlen(efi_char16_t *s)
 175 {
 176         return utf16_strnlen(s, ~0UL);
 177 }
 178
 179 /*
 180  * Return the number of bytes is the length of this string
 181  * Note: this is NOT the same as the number of unicode characters
 182  */
 183 static inline unsigned long
 184 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 185 {
 186         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 187 }
 188
 189 static inline int
 190 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 191 {
 192         while (1) {
 193                 if (len == 0)
 194                         return 0;
 195                 if (*a < *b)
 196                         return -1;
 197                 if (*a > *b)
 198                         return 1;
 199                 if (*a == 0) /* implies *b == 0 */
 200                         return 0;
 201                 a++;
 202                 b++;
 203                 len--;
 204         }
 205 }
 206
 207 static bool
 208 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 209                      unsigned long len)
 210 {
 211         struct efi_generic_dev_path *node;
 212         int offset = 0;
 213
 214         node = (struct efi_generic_dev_path *)buffer;
 215
 216         if (len < sizeof(*node))
 217                 return false;
 218
 219         while (offset <= len - sizeof(*node) &&
 220                node->length >= sizeof(*node) &&
 221                 node->length <= len - offset) {
 222                 offset += node->length;
 223
 224                 if ((node->type == EFI_DEV_END_PATH ||
 225                      node->type == EFI_DEV_END_PATH2) &&
 226                     node->sub_type == EFI_DEV_END_ENTIRE)
 227                         return true;
 228
 229                 node = (struct efi_generic_dev_path *)(buffer + offset);
 230         }
 231
 232         /*
 233          * If we're here then either node->length pointed past the end
 234          * of the buffer or we reached the end of the buffer without
 235          * finding a device path end node.
 236          */
 237         return false;
 238 }
 239
 240 static bool
 241 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 242                     unsigned long len)
 243 {
 244         /* An array of 16-bit integers */
 245         if ((len % 2) != 0)
 246                 return false;
 247
 248         return true;
 249 }
 250
 251 static bool
 252 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 253                      unsigned long len)
 254 {
 255         u16 filepathlength;
 256         int i, desclength = 0, namelen;
 257
 258         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 259
 260         /* Either "Boot" or "Driver" followed by four digits of hex */
 261         for (i = match; i < match+4; i++) {
 262                 if (var->VariableName[i] > 127 ||
 263                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 264                         return true;
 265         }
 266
 267         /* Reject it if there's 4 digits of hex and then further content */
 268         if (namelen > match + 4)
 269                 return false;
 270
 271         /* A valid entry must be at least 8 bytes */
 272         if (len < 8)
 273                 return false;
 274
 275         filepathlength = buffer[4] | buffer[5] << 8;
 276
 277         /*
 278          * There's no stored length for the description, so it has to be
 279          * found by hand
 280          */
 281         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 282
 283         /* Each boot entry must have a descriptor */
 284         if (!desclength)
 285                 return false;
 286
 287         /*
 288          * If the sum of the length of the description, the claimed filepath
 289          * length and the original header are greater than the length of the
 290          * variable, it's malformed
 291          */
 292         if ((desclength + filepathlength + 6) > len)
 293                 return false;
 294
 295         /*
 296          * And, finally, check the filepath
 297          */
 298         return validate_device_path(var, match, buffer + desclength + 6,
 299                                     filepathlength);
 300 }
 301
 302 static bool
 303 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 304                 unsigned long len)
 305 {
 306         /* A single 16-bit integer */
 307         if (len != 2)
 308                 return false;
 309
 310         return true;
 311 }
 312
 313 static bool
 314 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 315                       unsigned long len)
 316 {
 317         int i;
 318
 319         for (i = 0; i < len; i++) {
 320                 if (buffer[i] > 127)
 321                         return false;
 322
 323                 if (buffer[i] == 0)
 324                         return true;
 325         }
 326
 327         return false;
 328 }
 329
 330 struct variable_validate {
 331         char *name;
 332         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 333                          unsigned long len);
 334 };
 335
 336 static const struct variable_validate variable_validate[] = {
 337         { "BootNext", validate_uint16 },
 338         { "BootOrder", validate_boot_order },
 339         { "DriverOrder", validate_boot_order },
 340         { "Boot*", validate_load_option },
 341         { "Driver*", validate_load_option },
 342         { "ConIn", validate_device_path },
 343         { "ConInDev", validate_device_path },
 344         { "ConOut", validate_device_path },
 345         { "ConOutDev", validate_device_path },
 346         { "ErrOut", validate_device_path },
 347         { "ErrOutDev", validate_device_path },
 348         { "Timeout", validate_uint16 },
 349         { "Lang", validate_ascii_string },
 350         { "PlatformLang", validate_ascii_string },
 351         { "", NULL },
 352 };
 353
 354 static bool
 355 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 356 {
 357         int i;
 358         u16 *unicode_name = var->VariableName;
 359
 360         for (i = 0; variable_validate[i].validate != NULL; i++) {
 361                 const char *name = variable_validate[i].name;
 362                 int match;
 363
 364                 for (match = 0; ; match++) {
 365                         char c = name[match];
 366                         u16 u = unicode_name[match];
 367
 368                         /* All special variables are plain ascii */
 369                         if (u > 127)
 370                                 return true;
 371
 372                         /* Wildcard in the matching name means we've matched */
 373                         if (c == '*')
 374                                 return variable_validate[i].validate(var,
 375                                                              match, data, len);
 376
 377                         /* Case sensitive match */
 378                         if (c != u)
 379                                 break;
 380
 381                         /* Reached the end of the string while matching */
 382                         if (!c)
 383                                 return variable_validate[i].validate(var,
 384                                                              match, data, len);
 385                 }
 386         }
 387
 388         return true;
 389 }
 390
 391 static efi_status_t
 392 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 393 {
 394         efi_status_t status;
 395
 396         var->DataSize = 1024;
 397         status = efivars->ops->get_variable(var->VariableName,
 398                                             &var->VendorGuid,
 399                                             &var->Attributes,
 400                                             &var->DataSize,
 401                                             var->Data);
 402         return status;
 403 }
 404
 405 static efi_status_t
 406 get_var_data(struct efivars *efivars, struct efi_variable *var)
 407 {
 408         efi_status_t status;
 409         unsigned long flags;
 410
 411         spin_lock_irqsave(&efivars->lock, flags);
 412         status = get_var_data_locked(efivars, var);
 413         spin_unlock_irqrestore(&efivars->lock, flags);
 414
 415         if (status != EFI_SUCCESS) {
 416                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 417                         status);
 418         }
 419         return status;
 420 }
 421
 422 static efi_status_t
 423 check_var_size_locked(struct efivars *efivars, u32 attributes,
 424                         unsigned long size)
 425 {
 426         u64 storage_size, remaining_size, max_size;
 427         efi_status_t status;
 428         const struct efivar_operations *fops = efivars->ops;
 429
 430         if (!efivars->ops->query_variable_info)
 431                 return EFI_UNSUPPORTED;
 432
 433         status = fops->query_variable_info(attributes, &storage_size,
 434                                            &remaining_size, &max_size);
 435
 436         if (status != EFI_SUCCESS)
 437                 return status;
 438
 439         if (!storage_size || size > remaining_size || size > max_size ||
 440             (remaining_size - size) < (storage_size / 2))
 441                 return EFI_OUT_OF_RESOURCES;
 442
 443         return status;
 444 }
 445
 446
 447 static efi_status_t
 448 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
 449 {
 450         efi_status_t status;
 451         unsigned long flags;
 452
 453         spin_lock_irqsave(&efivars->lock, flags);
 454         status = check_var_size_locked(efivars, attributes, size);
 455         spin_unlock_irqrestore(&efivars->lock, flags);
 456
 457         return status;
 458 }
 459
 460 static ssize_t
 461 efivar_guid_read(struct efivar_entry *entry, char *buf)
 462 {
 463         struct efi_variable *var = &entry->var;
 464         char *str = buf;
 465
 466         if (!entry || !buf)
 467                 return 0;
 468
 469         efi_guid_unparse(&var->VendorGuid, str);
 470         str += strlen(str);
 471         str += sprintf(str, "\n");
 472
 473         return str - buf;
 474 }
 475
 476 static ssize_t
 477 efivar_attr_read(struct efivar_entry *entry, char *buf)
 478 {
 479         struct efi_variable *var = &entry->var;
 480         char *str = buf;
 481         efi_status_t status;
 482
 483         if (!entry || !buf)
 484                 return -EINVAL;
 485
 486         status = get_var_data(entry->efivars, var);
 487         if (status != EFI_SUCCESS)
 488                 return -EIO;
 489
 490         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 491                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 492         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 493                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 494         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 495                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 496         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 497                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 498         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 499                 str += sprintf(str,
 500                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 501         if (var->Attributes &
 502                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 503                 str += sprintf(str,
 504                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 505         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 506                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 507         return str - buf;
 508 }
 509
 510 static ssize_t
 511 efivar_size_read(struct efivar_entry *entry, char *buf)
 512 {
 513         struct efi_variable *var = &entry->var;
 514         char *str = buf;
 515         efi_status_t status;
 516
 517         if (!entry || !buf)
 518                 return -EINVAL;
 519
 520         status = get_var_data(entry->efivars, var);
 521         if (status != EFI_SUCCESS)
 522                 return -EIO;
 523
 524         str += sprintf(str, "0x%lx\n", var->DataSize);
 525         return str - buf;
 526 }
 527
 528 static ssize_t
 529 efivar_data_read(struct efivar_entry *entry, char *buf)
 530 {
 531         struct efi_variable *var = &entry->var;
 532         efi_status_t status;
 533
 534         if (!entry || !buf)
 535                 return -EINVAL;
 536
 537         status = get_var_data(entry->efivars, var);
 538         if (status != EFI_SUCCESS)
 539                 return -EIO;
 540
 541         memcpy(buf, var->Data, var->DataSize);
 542         return var->DataSize;
 543 }
 544 /*
 545  * We allow each variable to be edited via rewriting the
 546  * entire efi variable structure.
 547  */
 548 static ssize_t
 549 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 550 {
 551         struct efi_variable *new_var, *var = &entry->var;
 552         struct efivars *efivars = entry->efivars;
 553         efi_status_t status = EFI_NOT_FOUND;
 554
 555         if (count != sizeof(struct efi_variable))
 556                 return -EINVAL;
 557
 558         new_var = (struct efi_variable *)buf;
 559         /*
 560          * If only updating the variable data, then the name
 561          * and guid should remain the same
 562          */
 563         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 564                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 565                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 566                 return -EINVAL;
 567         }
 568
 569         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 570                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 571                 return -EINVAL;
 572         }
 573
 574         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 575             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 576                 printk(KERN_ERR "efivars: Malformed variable content\n");
 577                 return -EINVAL;
 578         }
 579
 580         spin_lock_irq(&efivars->lock);
 581
 582         status = check_var_size_locked(efivars, new_var->Attributes,
 583                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
 584
 585         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 586                 status = efivars->ops->set_variable(new_var->VariableName,
 587                                                     &new_var->VendorGuid,
 588                                                     new_var->Attributes,
 589                                                     new_var->DataSize,
 590                                                     new_var->Data);
 591
 592         spin_unlock_irq(&efivars->lock);
 593
 594         if (status != EFI_SUCCESS) {
 595                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 596                         status);
 597                 return -EIO;
 598         }
 599
 600         memcpy(&entry->var, new_var, count);
 601         return count;
 602 }
 603
 604 static ssize_t
 605 efivar_show_raw(struct efivar_entry *entry, char *buf)
 606 {
 607         struct efi_variable *var = &entry->var;
 608         efi_status_t status;
 609
 610         if (!entry || !buf)
 611                 return 0;
 612
 613         status = get_var_data(entry->efivars, var);
 614         if (status != EFI_SUCCESS)
 615                 return -EIO;
 616
 617         memcpy(buf, var, sizeof(*var));
 618         return sizeof(*var);
 619 }
 620
 621 /*
 622  * Generic read/write functions that call the specific functions of
 623  * the attributes...
 624  */
 625 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 626                                 char *buf)
 627 {
 628         struct efivar_entry *var = to_efivar_entry(kobj);
 629         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 630         ssize_t ret = -EIO;
 631
 632         if (!capable(CAP_SYS_ADMIN))
 633                 return -EACCES;
 634
 635         if (efivar_attr->show) {
 636                 ret = efivar_attr->show(var, buf);
 637         }
 638         return ret;
 639 }
 640
 641 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 642                                 const char *buf, size_t count)
 643 {
 644         struct efivar_entry *var = to_efivar_entry(kobj);
 645         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 646         ssize_t ret = -EIO;
 647
 648         if (!capable(CAP_SYS_ADMIN))
 649                 return -EACCES;
 650
 651         if (efivar_attr->store)
 652                 ret = efivar_attr->store(var, buf, count);
 653
 654         return ret;
 655 }
 656
 657 static const struct sysfs_ops efivar_attr_ops = {
 658         .show = efivar_attr_show,
 659         .store = efivar_attr_store,
 660 };
 661
 662 static void efivar_release(struct kobject *kobj)
 663 {
 664         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 665         kfree(var);
 666 }
 667
 668 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 669 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 670 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 671 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 672 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 673
 674 static struct attribute *def_attrs[] = {
 675         &efivar_attr_guid.attr,
 676         &efivar_attr_size.attr,
 677         &efivar_attr_attributes.attr,
 678         &efivar_attr_data.attr,
 679         &efivar_attr_raw_var.attr,
 680         NULL,
 681 };
 682
 683 static struct kobj_type efivar_ktype = {
 684         .release = efivar_release,
 685         .sysfs_ops = &efivar_attr_ops,
 686         .default_attrs = def_attrs,
 687 };
 688
 689 static inline void
 690 efivar_unregister(struct efivar_entry *var)
 691 {
 692         kobject_put(&var->kobj);
 693 }
 694
 695 static int efivarfs_file_open(struct inode *inode, struct file *file)
 696 {
 697         file->private_data = inode->i_private;
 698         return 0;
 699 }
 700
 701 static int efi_status_to_err(efi_status_t status)
 702 {
 703         int err;
 704
 705         switch (status) {
 706         case EFI_INVALID_PARAMETER:
 707                 err = -EINVAL;
 708                 break;
 709         case EFI_OUT_OF_RESOURCES:
 710                 err = -ENOSPC;
 711                 break;
 712         case EFI_DEVICE_ERROR:
 713                 err = -EIO;
 714                 break;
 715         case EFI_WRITE_PROTECTED:
 716                 err = -EROFS;
 717                 break;
 718         case EFI_SECURITY_VIOLATION:
 719                 err = -EACCES;
 720                 break;
 721         case EFI_NOT_FOUND:
 722                 err = -EIO;
 723                 break;
 724         default:
 725                 err = -EINVAL;
 726         }
 727
 728         return err;
 729 }
 730
 731 static ssize_t efivarfs_file_write(struct file *file,
 732                 const char __user *userbuf, size_t count, loff_t *ppos)
 733 {
 734         struct efivar_entry *var = file->private_data;
 735         struct efivars *efivars;
 736         efi_status_t status;
 737         void *data;
 738         u32 attributes;
 739         struct inode *inode = file->f_mapping->host;
 740         unsigned long datasize = count - sizeof(attributes);
 741         unsigned long newdatasize, varsize;
 742         ssize_t bytes = 0;
 743
 744         if (count < sizeof(attributes))
 745                 return -EINVAL;
 746
 747         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 748                 return -EFAULT;
 749
 750         if (attributes & ~(EFI_VARIABLE_MASK))
 751                 return -EINVAL;
 752
 753         efivars = var->efivars;
 754
 755         /*
 756          * Ensure that the user can't allocate arbitrarily large
 757          * amounts of memory. Pick a default size of 64K if
 758          * QueryVariableInfo() isn't supported by the firmware.
 759          */
 760
 761         varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
 762         status = check_var_size(efivars, attributes, varsize);
 763
 764         if (status != EFI_SUCCESS) {
 765                 if (status != EFI_UNSUPPORTED)
 766                         return efi_status_to_err(status);
 767
 768                 if (datasize > 65536)
 769                         return -ENOSPC;
 770         }
 771
 772         data = kmalloc(datasize, GFP_KERNEL);
 773         if (!data)
 774                 return -ENOMEM;
 775
 776         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 777                 bytes = -EFAULT;
 778                 goto out;
 779         }
 780
 781         if (validate_var(&var->var, data, datasize) == false) {
 782                 bytes = -EINVAL;
 783                 goto out;
 784         }
 785
 786         /*
 787          * The lock here protects the get_variable call, the conditional
 788          * set_variable call, and removal of the variable from the efivars
 789          * list (in the case of an authenticated delete).
 790          */
 791         spin_lock_irq(&efivars->lock);
 792
 793         /*
 794          * Ensure that the available space hasn't shrunk below the safe level
 795          */
 796
 797         status = check_var_size_locked(efivars, attributes, varsize);
 798
 799         if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
 800                 spin_unlock_irq(&efivars->lock);
 801                 kfree(data);
 802
 803                 return efi_status_to_err(status);
 804         }
 805
 806         status = efivars->ops->set_variable(var->var.VariableName,
 807                                             &var->var.VendorGuid,
 808                                             attributes, datasize,
 809                                             data);
 810
 811         if (status != EFI_SUCCESS) {
 812                 spin_unlock_irq(&efivars->lock);
 813                 kfree(data);
 814
 815                 return efi_status_to_err(status);
 816         }
 817
 818         bytes = count;
 819
 820         /*
 821          * Writing to the variable may have caused a change in size (which
 822          * could either be an append or an overwrite), or the variable to be
 823          * deleted. Perform a GetVariable() so we can tell what actually
 824          * happened.
 825          */
 826         newdatasize = 0;
 827         status = efivars->ops->get_variable(var->var.VariableName,
 828                                             &var->var.VendorGuid,
 829                                             NULL, &newdatasize,
 830                                             NULL);
 831
 832         if (status == EFI_BUFFER_TOO_SMALL) {
 833                 spin_unlock_irq(&efivars->lock);
 834                 mutex_lock(&inode->i_mutex);
 835                 i_size_write(inode, newdatasize + sizeof(attributes));
 836                 mutex_unlock(&inode->i_mutex);
 837
 838         } else if (status == EFI_NOT_FOUND) {
 839                 list_del(&var->list);
 840                 spin_unlock_irq(&efivars->lock);
 841                 efivar_unregister(var);
 842                 drop_nlink(inode);
 843                 d_delete(file->f_dentry);
 844                 dput(file->f_dentry);
 845
 846         } else {
 847                 spin_unlock_irq(&efivars->lock);
 848                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
 849                                 "status = %lx\n", status);
 850         }
 851
 852 out:
 853         kfree(data);
 854
 855         return bytes;
 856 }
 857
 858 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 859                 size_t count, loff_t *ppos)
 860 {
 861         struct efivar_entry *var = file->private_data;
 862         struct efivars *efivars = var->efivars;
 863         efi_status_t status;
 864         unsigned long datasize = 0;
 865         u32 attributes;
 866         void *data;
 867         ssize_t size = 0;
 868
 869         spin_lock_irq(&efivars->lock);
 870         status = efivars->ops->get_variable(var->var.VariableName,
 871                                             &var->var.VendorGuid,
 872                                             &attributes, &datasize, NULL);
 873         spin_unlock_irq(&efivars->lock);
 874
 875         if (status != EFI_BUFFER_TOO_SMALL)
 876                 return efi_status_to_err(status);
 877
 878         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 879
 880         if (!data)
 881                 return -ENOMEM;
 882
 883         spin_lock_irq(&efivars->lock);
 884         status = efivars->ops->get_variable(var->var.VariableName,
 885                                             &var->var.VendorGuid,
 886                                             &attributes, &datasize,
 887                                             (data + sizeof(attributes)));
 888         spin_unlock_irq(&efivars->lock);
 889
 890         if (status != EFI_SUCCESS) {
 891                 size = efi_status_to_err(status);
 892                 goto out_free;
 893         }
 894
 895         memcpy(data, &attributes, sizeof(attributes));
 896         size = simple_read_from_buffer(userbuf, count, ppos,
 897                                        data, datasize + sizeof(attributes));
 898 out_free:
 899         kfree(data);
 900
 901         return size;
 902 }
 903
 904 static void efivarfs_evict_inode(struct inode *inode)
 905 {
 906         clear_inode(inode);
 907 }
 908
 909 static const struct super_operations efivarfs_ops = {
 910         .statfs = simple_statfs,
 911         .drop_inode = generic_delete_inode,
 912         .evict_inode = efivarfs_evict_inode,
 913         .show_options = generic_show_options,
 914 };
 915
 916 static struct super_block *efivarfs_sb;
 917
 918 static const struct inode_operations efivarfs_dir_inode_operations;
 919
 920 static const struct file_operations efivarfs_file_operations = {
 921         .open   = efivarfs_file_open,
 922         .read   = efivarfs_file_read,
 923         .write  = efivarfs_file_write,
 924         .llseek = no_llseek,
 925 };
 926
 927 static struct inode *efivarfs_get_inode(struct super_block *sb,
 928                                 const struct inode *dir, int mode, dev_t dev)
 929 {
 930         struct inode *inode = new_inode(sb);
 931
 932         if (inode) {
 933                 inode->i_ino = get_next_ino();
 934                 inode->i_mode = mode;
 935                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 936                 switch (mode & S_IFMT) {
 937                 case S_IFREG:
 938                         inode->i_fop = &efivarfs_file_operations;
 939                         break;
 940                 case S_IFDIR:
 941                         inode->i_op = &efivarfs_dir_inode_operations;
 942                         inode->i_fop = &simple_dir_operations;
 943                         inc_nlink(inode);
 944                         break;
 945                 }
 946         }
 947         return inode;
 948 }
 949
 950 /*
 951  * Return true if 'str' is a valid efivarfs filename of the form,
 952  *
 953  *      VariableName-12345678-1234-1234-1234-1234567891bc
 954  */
 955 static bool efivarfs_valid_name(const char *str, int len)
 956 {
 957         static const char dashes[GUID_LEN] = {
 958                 [8] = 1, [13] = 1, [18] = 1, [23] = 1
 959         };
 960         const char *s = str + len - GUID_LEN;
 961         int i;
 962
 963         /*
 964          * We need a GUID, plus at least one letter for the variable name,
 965          * plus the '-' separator
 966          */
 967         if (len < GUID_LEN + 2)
 968                 return false;
 969
 970         /* GUID must be preceded by a '-' */
 971         if (*(s - 1) != '-')
 972                 return false;
 973
 974         /*
 975          * Validate that 's' is of the correct format, e.g.
 976          *
 977          *      12345678-1234-1234-1234-123456789abc
 978          */
 979         for (i = 0; i < GUID_LEN; i++) {
 980                 if (dashes[i]) {
 981                         if (*s++ != '-')
 982                                 return false;
 983                 } else {
 984                         if (!isxdigit(*s++))
 985                                 return false;
 986                 }
 987         }
 988
 989         return true;
 990 }
 991
 992 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
 993 {
 994         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
 995         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
 996         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
 997         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
 998         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
 999         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
1000         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
1001         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
1002         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
1003         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1004         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1005         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1006         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1007         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1008         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1009         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1010 }
1011
1012 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1013                           umode_t mode, bool excl)
1014 {
1015         struct inode *inode;
1016         struct efivars *efivars = &__efivars;
1017         struct efivar_entry *var;
1018         int namelen, i = 0, err = 0;
1019
1020         if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1021                 return -EINVAL;
1022
1023         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1024         if (!inode)
1025                 return -ENOMEM;
1026
1027         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1028         if (!var) {
1029                 err = -ENOMEM;
1030                 goto out;
1031         }
1032
1033         /* length of the variable name itself: remove GUID and separator */
1034         namelen = dentry->d_name.len - GUID_LEN - 1;
1035
1036         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1037                         &var->var.VendorGuid);
1038
1039         for (i = 0; i < namelen; i++)
1040                 var->var.VariableName[i] = dentry->d_name.name[i];
1041
1042         var->var.VariableName[i] = '\0';
1043
1044         inode->i_private = var;
1045         var->efivars = efivars;
1046         var->kobj.kset = efivars->kset;
1047
1048         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1049                              dentry->d_name.name);
1050         if (err)
1051                 goto out;
1052
1053         kobject_uevent(&var->kobj, KOBJ_ADD);
1054         spin_lock_irq(&efivars->lock);
1055         list_add(&var->list, &efivars->list);
1056         spin_unlock_irq(&efivars->lock);
1057         d_instantiate(dentry, inode);
1058         dget(dentry);
1059 out:
1060         if (err) {
1061                 kfree(var);
1062                 iput(inode);
1063         }
1064         return err;
1065 }
1066
1067 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1068 {
1069         struct efivar_entry *var = dentry->d_inode->i_private;
1070         struct efivars *efivars = var->efivars;
1071         efi_status_t status;
1072
1073         spin_lock_irq(&efivars->lock);
1074
1075         status = efivars->ops->set_variable(var->var.VariableName,
1076                                             &var->var.VendorGuid,
1077                                             0, 0, NULL);
1078
1079         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1080                 list_del(&var->list);
1081                 spin_unlock_irq(&efivars->lock);
1082                 efivar_unregister(var);
1083                 drop_nlink(dentry->d_inode);
1084                 dput(dentry);
1085                 return 0;
1086         }
1087
1088         spin_unlock_irq(&efivars->lock);
1089         return -EINVAL;
1090 };
1091
1092 /*
1093  * Compare two efivarfs file names.
1094  *
1095  * An efivarfs filename is composed of two parts,
1096  *
1097  *      1. A case-sensitive variable name
1098  *      2. A case-insensitive GUID
1099  *
1100  * So we need to perform a case-sensitive match on part 1 and a
1101  * case-insensitive match on part 2.
1102  */
1103 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1104                               const struct dentry *dentry, const struct inode *inode,
1105                               unsigned int len, const char *str,
1106                               const struct qstr *name)
1107 {
1108         int guid = len - GUID_LEN;
1109
1110         if (name->len != len)
1111                 return 1;
1112
1113         /* Case-sensitive compare for the variable name */
1114         if (memcmp(str, name->name, guid))
1115                 return 1;
1116
1117         /* Case-insensitive compare for the GUID */
1118         return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1119 }
1120
1121 static int efivarfs_d_hash(const struct dentry *dentry,
1122                            const struct inode *inode, struct qstr *qstr)
1123 {
1124         unsigned long hash = init_name_hash();
1125         const unsigned char *s = qstr->name;
1126         unsigned int len = qstr->len;
1127
1128         if (!efivarfs_valid_name(s, len))
1129                 return -EINVAL;
1130
1131         while (len-- > GUID_LEN)
1132                 hash = partial_name_hash(*s++, hash);
1133
1134         /* GUID is case-insensitive. */
1135         while (len--)
1136                 hash = partial_name_hash(tolower(*s++), hash);
1137
1138         qstr->hash = end_name_hash(hash);
1139         return 0;
1140 }
1141
1142 /*
1143  * Retaining negative dentries for an in-memory filesystem just wastes
1144  * memory and lookup time: arrange for them to be deleted immediately.
1145  */
1146 static int efivarfs_delete_dentry(const struct dentry *dentry)
1147 {
1148         return 1;
1149 }
1150
1151 static struct dentry_operations efivarfs_d_ops = {
1152         .d_compare = efivarfs_d_compare,
1153         .d_hash = efivarfs_d_hash,
1154         .d_delete = efivarfs_delete_dentry,
1155 };
1156
1157 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1158 {
1159         struct dentry *d;
1160         struct qstr q;
1161         int err;
1162
1163         q.name = name;
1164         q.len = strlen(name);
1165
1166         err = efivarfs_d_hash(NULL, NULL, &q);
1167         if (err)
1168                 return ERR_PTR(err);
1169
1170         d = d_alloc(parent, &q);
1171         if (d)
1172                 return d;
1173
1174         return ERR_PTR(-ENOMEM);
1175 }
1176
1177 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1178 {
1179         struct inode *inode = NULL;
1180         struct dentry *root;
1181         struct efivar_entry *entry, *n;
1182         struct efivars *efivars = &__efivars;
1183         char *name;
1184         int err = -ENOMEM;
1185
1186         efivarfs_sb = sb;
1187
1188         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1189         sb->s_blocksize         = PAGE_CACHE_SIZE;
1190         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1191         sb->s_magic             = EFIVARFS_MAGIC;
1192         sb->s_op                = &efivarfs_ops;
1193         sb->s_d_op              = &efivarfs_d_ops;
1194         sb->s_time_gran         = 1;
1195
1196         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1197         if (!inode)
1198                 return -ENOMEM;
1199         inode->i_op = &efivarfs_dir_inode_operations;
1200
1201         root = d_make_root(inode);
1202         sb->s_root = root;
1203         if (!root)
1204                 return -ENOMEM;
1205
1206         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1207                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1208                 unsigned long size = 0;
1209                 int len, i;
1210
1211                 inode = NULL;
1212
1213                 len = utf16_strlen(entry->var.VariableName);
1214
1215                 /* name, plus '-', plus GUID, plus NUL*/
1216                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1217                 if (!name)
1218                         goto fail;
1219
1220                 for (i = 0; i < len; i++)
1221                         name[i] = entry->var.VariableName[i] & 0xFF;
1222
1223                 name[len] = '-';
1224
1225                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1226
1227                 name[len+GUID_LEN+1] = '\0';
1228
1229                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1230                                           S_IFREG | 0644, 0);
1231                 if (!inode)
1232                         goto fail_name;
1233
1234                 dentry = efivarfs_alloc_dentry(root, name);
1235                 if (IS_ERR(dentry)) {
1236                         err = PTR_ERR(dentry);
1237                         goto fail_inode;
1238                 }
1239
1240                 /* copied by the above to local storage in the dentry. */
1241                 kfree(name);
1242
1243                 spin_lock_irq(&efivars->lock);
1244                 efivars->ops->get_variable(entry->var.VariableName,
1245                                            &entry->var.VendorGuid,
1246                                            &entry->var.Attributes,
1247                                            &size,
1248                                            NULL);
1249                 spin_unlock_irq(&efivars->lock);
1250
1251                 mutex_lock(&inode->i_mutex);
1252                 inode->i_private = entry;
1253                 i_size_write(inode, size+4);
1254                 mutex_unlock(&inode->i_mutex);
1255                 d_add(dentry, inode);
1256         }
1257
1258         return 0;
1259
1260 fail_inode:
1261         iput(inode);
1262 fail_name:
1263         kfree(name);
1264 fail:
1265         return err;
1266 }
1267
1268 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1269                                     int flags, const char *dev_name, void *data)
1270 {
1271         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1272 }
1273
1274 static void efivarfs_kill_sb(struct super_block *sb)
1275 {
1276         kill_litter_super(sb);
1277         efivarfs_sb = NULL;
1278 }
1279
1280 static struct file_system_type efivarfs_type = {
1281         .name    = "efivarfs",
1282         .mount   = efivarfs_mount,
1283         .kill_sb = efivarfs_kill_sb,
1284 };
1285
1286 /*
1287  * Handle negative dentry.
1288  */
1289 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1290                                       unsigned int flags)
1291 {
1292         if (dentry->d_name.len > NAME_MAX)
1293                 return ERR_PTR(-ENAMETOOLONG);
1294         d_add(dentry, NULL);
1295         return NULL;
1296 }
1297
1298 static const struct inode_operations efivarfs_dir_inode_operations = {
1299         .lookup = efivarfs_lookup,
1300         .unlink = efivarfs_unlink,
1301         .create = efivarfs_create,
1302 };
1303
1304 static struct pstore_info efi_pstore_info;
1305
1306 #ifdef CONFIG_PSTORE
1307
1308 static int efi_pstore_open(struct pstore_info *psi)
1309 {
1310         struct efivars *efivars = psi->data;
1311
1312         spin_lock_irq(&efivars->lock);
1313         efivars->walk_entry = list_first_entry(&efivars->list,
1314                                                struct efivar_entry, list);
1315         return 0;
1316 }
1317
1318 static int efi_pstore_close(struct pstore_info *psi)
1319 {
1320         struct efivars *efivars = psi->data;
1321
1322         spin_unlock_irq(&efivars->lock);
1323         return 0;
1324 }
1325
1326 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1327                                int *count, struct timespec *timespec,
1328                                char **buf, struct pstore_info *psi)
1329 {
1330         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1331         struct efivars *efivars = psi->data;
1332         char name[DUMP_NAME_LEN];
1333         int i;
1334         int cnt;
1335         unsigned int part, size;
1336         unsigned long time;
1337
1338         while (&efivars->walk_entry->list != &efivars->list) {
1339                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1340                                  vendor)) {
1341                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1342                                 name[i] = efivars->walk_entry->var.VariableName[i];
1343                         }
1344                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1345                                    type, &part, &cnt, &time) == 4) {
1346                                 *id = part;
1347                                 *count = cnt;
1348                                 timespec->tv_sec = time;
1349                                 timespec->tv_nsec = 0;
1350                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1351                                    type, &part, &time) == 3) {
1352                                 /*
1353                                  * Check if an old format,
1354                                  * which doesn't support holding
1355                                  * multiple logs, remains.
1356                                  */
1357                                 *id = part;
1358                                 *count = 0;
1359                                 timespec->tv_sec = time;
1360                                 timespec->tv_nsec = 0;
1361                         } else {
1362                                 efivars->walk_entry = list_entry(
1363                                                 efivars->walk_entry->list.next,
1364                                                 struct efivar_entry, list);
1365                                 continue;
1366                         }
1367
1368                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1369                         size = efivars->walk_entry->var.DataSize;
1370                         *buf = kmalloc(size, GFP_KERNEL);
1371                         if (*buf == NULL)
1372                                 return -ENOMEM;
1373                         memcpy(*buf, efivars->walk_entry->var.Data,
1374                                size);
1375                         efivars->walk_entry = list_entry(
1376                                         efivars->walk_entry->list.next,
1377                                         struct efivar_entry, list);
1378                         return size;
1379                 }
1380                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1381                                                  struct efivar_entry, list);
1382         }
1383         return 0;
1384 }
1385
1386 static int efi_pstore_write(enum pstore_type_id type,
1387                 enum kmsg_dump_reason reason, u64 *id,
1388                 unsigned int part, int count, size_t size,
1389                 struct pstore_info *psi)
1390 {
1391         char name[DUMP_NAME_LEN];
1392         efi_char16_t efi_name[DUMP_NAME_LEN];
1393         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1394         struct efivars *efivars = psi->data;
1395         int i, ret = 0;
1396         efi_status_t status = EFI_NOT_FOUND;
1397         unsigned long flags;
1398
1399         spin_lock_irqsave(&efivars->lock, flags);
1400
1401         /*
1402          * Check if there is a space enough to log.
1403          * size: a size of logging data
1404          * DUMP_NAME_LEN * 2: a maximum size of variable name
1405          */
1406
1407         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1408                                          size + DUMP_NAME_LEN * 2);
1409
1410         if (status) {
1411                 spin_unlock_irqrestore(&efivars->lock, flags);
1412                 *id = part;
1413                 return -ENOSPC;
1414         }
1415
1416         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1417                 get_seconds());
1418
1419         for (i = 0; i < DUMP_NAME_LEN; i++)
1420                 efi_name[i] = name[i];
1421
1422         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1423                                    size, psi->buf);
1424
1425         spin_unlock_irqrestore(&efivars->lock, flags);
1426
1427         if (size)
1428                 ret = efivar_create_sysfs_entry(efivars,
1429                                           utf16_strsize(efi_name,
1430                                                         DUMP_NAME_LEN * 2),
1431                                           efi_name, &vendor);
1432
1433         *id = part;
1434         return ret;
1435 };
1436
1437 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1438                             struct timespec time, struct pstore_info *psi)
1439 {
1440         char name[DUMP_NAME_LEN];
1441         efi_char16_t efi_name[DUMP_NAME_LEN];
1442         char name_old[DUMP_NAME_LEN];
1443         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1444         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1445         struct efivars *efivars = psi->data;
1446         struct efivar_entry *entry, *found = NULL;
1447         int i;
1448
1449         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1450                 time.tv_sec);
1451
1452         spin_lock_irq(&efivars->lock);
1453
1454         for (i = 0; i < DUMP_NAME_LEN; i++)
1455                 efi_name[i] = name[i];
1456
1457         /*
1458          * Clean up an entry with the same name
1459          */
1460
1461         list_for_each_entry(entry, &efivars->list, list) {
1462                 get_var_data_locked(efivars, &entry->var);
1463
1464                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1465                         continue;
1466                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1467                                   utf16_strlen(efi_name))) {
1468                         /*
1469                          * Check if an old format,
1470                          * which doesn't support holding
1471                          * multiple logs, remains.
1472                          */
1473                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1474                                 (unsigned int)id, time.tv_sec);
1475
1476                         for (i = 0; i < DUMP_NAME_LEN; i++)
1477                                 efi_name_old[i] = name_old[i];
1478
1479                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1480                                           utf16_strlen(efi_name_old)))
1481                                 continue;
1482                 }
1483
1484                 /* found */
1485                 found = entry;
1486                 efivars->ops->set_variable(entry->var.VariableName,
1487                                            &entry->var.VendorGuid,
1488                                            PSTORE_EFI_ATTRIBUTES,
1489                                            0, NULL);
1490                 break;
1491         }
1492
1493         if (found)
1494                 list_del(&found->list);
1495
1496         spin_unlock_irq(&efivars->lock);
1497
1498         if (found)
1499                 efivar_unregister(found);
1500
1501         return 0;
1502 }
1503 #else
1504 static int efi_pstore_open(struct pstore_info *psi)
1505 {
1506         return 0;
1507 }
1508
1509 static int efi_pstore_close(struct pstore_info *psi)
1510 {
1511         return 0;
1512 }
1513
1514 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1515                                struct timespec *timespec,
1516                                char **buf, struct pstore_info *psi)
1517 {
1518         return -1;
1519 }
1520
1521 static int efi_pstore_write(enum pstore_type_id type,
1522                 enum kmsg_dump_reason reason, u64 *id,
1523                 unsigned int part, int count, size_t size,
1524                 struct pstore_info *psi)
1525 {
1526         return 0;
1527 }
1528
1529 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1530                             struct timespec time, struct pstore_info *psi)
1531 {
1532         return 0;
1533 }
1534 #endif
1535
1536 static struct pstore_info efi_pstore_info = {
1537         .owner          = THIS_MODULE,
1538         .name           = "efi",
1539         .open           = efi_pstore_open,
1540         .close          = efi_pstore_close,
1541         .read           = efi_pstore_read,
1542         .write          = efi_pstore_write,
1543         .erase          = efi_pstore_erase,
1544 };
1545
1546 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1547                              struct bin_attribute *bin_attr,
1548                              char *buf, loff_t pos, size_t count)
1549 {
1550         struct efi_variable *new_var = (struct efi_variable *)buf;
1551         struct efivars *efivars = bin_attr->private;
1552         struct efivar_entry *search_efivar, *n;
1553         unsigned long strsize1, strsize2;
1554         efi_status_t status = EFI_NOT_FOUND;
1555         int found = 0;
1556
1557         if (!capable(CAP_SYS_ADMIN))
1558                 return -EACCES;
1559
1560         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1561             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1562                 printk(KERN_ERR "efivars: Malformed variable content\n");
1563                 return -EINVAL;
1564         }
1565
1566         spin_lock_irq(&efivars->lock);
1567
1568         /*
1569          * Does this variable already exist?
1570          */
1571         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1572                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1573                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1574                 if (strsize1 == strsize2 &&
1575                         !memcmp(&(search_efivar->var.VariableName),
1576                                 new_var->VariableName, strsize1) &&
1577                         !efi_guidcmp(search_efivar->var.VendorGuid,
1578                                 new_var->VendorGuid)) {
1579                         found = 1;
1580                         break;
1581                 }
1582         }
1583         if (found) {
1584                 spin_unlock_irq(&efivars->lock);
1585                 return -EINVAL;
1586         }
1587
1588         status = check_var_size_locked(efivars, new_var->Attributes,
1589                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
1590
1591         if (status && status != EFI_UNSUPPORTED) {
1592                 spin_unlock_irq(&efivars->lock);
1593                 return efi_status_to_err(status);
1594         }
1595
1596         /* now *really* create the variable via EFI */
1597         status = efivars->ops->set_variable(new_var->VariableName,
1598                                             &new_var->VendorGuid,
1599                                             new_var->Attributes,
1600                                             new_var->DataSize,
1601                                             new_var->Data);
1602
1603         if (status != EFI_SUCCESS) {
1604                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1605                         status);
1606                 spin_unlock_irq(&efivars->lock);
1607                 return -EIO;
1608         }
1609         spin_unlock_irq(&efivars->lock);
1610
1611         /* Create the entry in sysfs.  Locking is not required here */
1612         status = efivar_create_sysfs_entry(efivars,
1613                                            utf16_strsize(new_var->VariableName,
1614                                                          1024),
1615                                            new_var->VariableName,
1616                                            &new_var->VendorGuid);
1617         if (status) {
1618                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1619         }
1620         return count;
1621 }
1622
1623 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1624                              struct bin_attribute *bin_attr,
1625                              char *buf, loff_t pos, size_t count)
1626 {
1627         struct efi_variable *del_var = (struct efi_variable *)buf;
1628         struct efivars *efivars = bin_attr->private;
1629         struct efivar_entry *search_efivar, *n;
1630         unsigned long strsize1, strsize2;
1631         efi_status_t status = EFI_NOT_FOUND;
1632         int found = 0;
1633
1634         if (!capable(CAP_SYS_ADMIN))
1635                 return -EACCES;
1636
1637         spin_lock_irq(&efivars->lock);
1638
1639         /*
1640          * Does this variable already exist?
1641          */
1642         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1643                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1644                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1645                 if (strsize1 == strsize2 &&
1646                         !memcmp(&(search_efivar->var.VariableName),
1647                                 del_var->VariableName, strsize1) &&
1648                         !efi_guidcmp(search_efivar->var.VendorGuid,
1649                                 del_var->VendorGuid)) {
1650                         found = 1;
1651                         break;
1652                 }
1653         }
1654         if (!found) {
1655                 spin_unlock_irq(&efivars->lock);
1656                 return -EINVAL;
1657         }
1658         /* force the Attributes/DataSize to 0 to ensure deletion */
1659         del_var->Attributes = 0;
1660         del_var->DataSize = 0;
1661
1662         status = efivars->ops->set_variable(del_var->VariableName,
1663                                             &del_var->VendorGuid,
1664                                             del_var->Attributes,
1665                                             del_var->DataSize,
1666                                             del_var->Data);
1667
1668         if (status != EFI_SUCCESS) {
1669                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1670                         status);
1671                 spin_unlock_irq(&efivars->lock);
1672                 return -EIO;
1673         }
1674         list_del(&search_efivar->list);
1675         /* We need to release this lock before unregistering. */
1676         spin_unlock_irq(&efivars->lock);
1677         efivar_unregister(search_efivar);
1678
1679         /* It's dead Jim.... */
1680         return count;
1681 }
1682
1683 /*
1684  * Let's not leave out systab information that snuck into
1685  * the efivars driver
1686  */
1687 static ssize_t systab_show(struct kobject *kobj,
1688                            struct kobj_attribute *attr, char *buf)
1689 {
1690         char *str = buf;
1691
1692         if (!kobj || !buf)
1693                 return -EINVAL;
1694
1695         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1696                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1697         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1698                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1699         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1700                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1701         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1702                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1703         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1704                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1705         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1706                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1707         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1708                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1709
1710         return str - buf;
1711 }
1712
1713 static struct kobj_attribute efi_attr_systab =
1714                         __ATTR(systab, 0400, systab_show, NULL);
1715
1716 static struct attribute *efi_subsys_attrs[] = {
1717         &efi_attr_systab.attr,
1718         NULL,   /* maybe more in the future? */
1719 };
1720
1721 static struct attribute_group efi_subsys_attr_group = {
1722         .attrs = efi_subsys_attrs,
1723 };
1724
1725 static struct kobject *efi_kobj;
1726
1727 /*
1728  * efivar_create_sysfs_entry()
1729  * Requires:
1730  *    variable_name_size = number of bytes required to hold
1731  *                         variable_name (not counting the NULL
1732  *                         character at the end.
1733  *    efivars->lock is not held on entry or exit.
1734  * Returns 1 on failure, 0 on success
1735  */
1736 static int
1737 efivar_create_sysfs_entry(struct efivars *efivars,
1738                           unsigned long variable_name_size,
1739                           efi_char16_t *variable_name,
1740                           efi_guid_t *vendor_guid)
1741 {
1742         int i, short_name_size;
1743         char *short_name;
1744         struct efivar_entry *new_efivar;
1745
1746         /*
1747          * Length of the variable bytes in ASCII, plus the '-' separator,
1748          * plus the GUID, plus trailing NUL
1749          */
1750         short_name_size = variable_name_size / sizeof(efi_char16_t)
1751                                 + 1 + GUID_LEN + 1;
1752
1753         short_name = kzalloc(short_name_size, GFP_KERNEL);
1754         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1755
1756         if (!short_name || !new_efivar)  {
1757                 kfree(short_name);
1758                 kfree(new_efivar);
1759                 return 1;
1760         }
1761
1762         new_efivar->efivars = efivars;
1763         memcpy(new_efivar->var.VariableName, variable_name,
1764                 variable_name_size);
1765         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1766
1767         /* Convert Unicode to normal chars (assume top bits are 0),
1768            ala UTF-8 */
1769         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1770                 short_name[i] = variable_name[i] & 0xFF;
1771         }
1772         /* This is ugly, but necessary to separate one vendor's
1773            private variables from another's.         */
1774
1775         *(short_name + strlen(short_name)) = '-';
1776         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1777
1778         new_efivar->kobj.kset = efivars->kset;
1779         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1780                                  "%s", short_name);
1781         if (i) {
1782                 kfree(short_name);
1783                 kfree(new_efivar);
1784                 return 1;
1785         }
1786
1787         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1788         kfree(short_name);
1789         short_name = NULL;
1790
1791         spin_lock_irq(&efivars->lock);
1792         list_add(&new_efivar->list, &efivars->list);
1793         spin_unlock_irq(&efivars->lock);
1794
1795         return 0;
1796 }
1797
1798 static int
1799 create_efivars_bin_attributes(struct efivars *efivars)
1800 {
1801         struct bin_attribute *attr;
1802         int error;
1803
1804         /* new_var */
1805         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1806         if (!attr)
1807                 return -ENOMEM;
1808
1809         attr->attr.name = "new_var";
1810         attr->attr.mode = 0200;
1811         attr->write = efivar_create;
1812         attr->private = efivars;
1813         efivars->new_var = attr;
1814
1815         /* del_var */
1816         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1817         if (!attr) {
1818                 error = -ENOMEM;
1819                 goto out_free;
1820         }
1821         attr->attr.name = "del_var";
1822         attr->attr.mode = 0200;
1823         attr->write = efivar_delete;
1824         attr->private = efivars;
1825         efivars->del_var = attr;
1826
1827         sysfs_bin_attr_init(efivars->new_var);
1828         sysfs_bin_attr_init(efivars->del_var);
1829
1830         /* Register */
1831         error = sysfs_create_bin_file(&efivars->kset->kobj,
1832                                       efivars->new_var);
1833         if (error) {
1834                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1835                         " due to error %d\n", error);
1836                 goto out_free;
1837         }
1838         error = sysfs_create_bin_file(&efivars->kset->kobj,
1839                                       efivars->del_var);
1840         if (error) {
1841                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1842                         " due to error %d\n", error);
1843                 sysfs_remove_bin_file(&efivars->kset->kobj,
1844                                       efivars->new_var);
1845                 goto out_free;
1846         }
1847
1848         return 0;
1849 out_free:
1850         kfree(efivars->del_var);
1851         efivars->del_var = NULL;
1852         kfree(efivars->new_var);
1853         efivars->new_var = NULL;
1854         return error;
1855 }
1856
1857 void unregister_efivars(struct efivars *efivars)
1858 {
1859         struct efivar_entry *entry, *n;
1860
1861         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1862                 spin_lock_irq(&efivars->lock);
1863                 list_del(&entry->list);
1864                 spin_unlock_irq(&efivars->lock);
1865                 efivar_unregister(entry);
1866         }
1867         if (efivars->new_var)
1868                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1869         if (efivars->del_var)
1870                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1871         kfree(efivars->new_var);
1872         kfree(efivars->del_var);
1873         kobject_put(efivars->kobject);
1874         kset_unregister(efivars->kset);
1875 }
1876 EXPORT_SYMBOL_GPL(unregister_efivars);
1877
1878 int register_efivars(struct efivars *efivars,
1879                      const struct efivar_operations *ops,
1880                      struct kobject *parent_kobj)
1881 {
1882         efi_status_t status = EFI_NOT_FOUND;
1883         efi_guid_t vendor_guid;
1884         efi_char16_t *variable_name;
1885         unsigned long variable_name_size = 1024;
1886         int error = 0;
1887
1888         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1889         if (!variable_name) {
1890                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1891                 return -ENOMEM;
1892         }
1893
1894         spin_lock_init(&efivars->lock);
1895         INIT_LIST_HEAD(&efivars->list);
1896         efivars->ops = ops;
1897
1898         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1899         if (!efivars->kset) {
1900                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1901                 error = -ENOMEM;
1902                 goto out;
1903         }
1904
1905         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1906         if (!efivars->kobject) {
1907                 pr_err("efivars: Subsystem registration failed.\n");
1908                 error = -ENOMEM;
1909                 kset_unregister(efivars->kset);
1910                 goto out;
1911         }
1912
1913         /*
1914          * Per EFI spec, the maximum storage allocated for both
1915          * the variable name and variable data is 1024 bytes.
1916          */
1917
1918         do {
1919                 variable_name_size = 1024;
1920
1921                 status = ops->get_next_variable(&variable_name_size,
1922                                                 variable_name,
1923                                                 &vendor_guid);
1924                 switch (status) {
1925                 case EFI_SUCCESS:
1926                         efivar_create_sysfs_entry(efivars,
1927                                                   variable_name_size,
1928                                                   variable_name,
1929                                                   &vendor_guid);
1930                         break;
1931                 case EFI_NOT_FOUND:
1932                         break;
1933                 default:
1934                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1935                                 status);
1936                         status = EFI_NOT_FOUND;
1937                         break;
1938                 }
1939         } while (status != EFI_NOT_FOUND);
1940
1941         error = create_efivars_bin_attributes(efivars);
1942         if (error)
1943                 unregister_efivars(efivars);
1944
1945         efivars->efi_pstore_info = efi_pstore_info;
1946
1947         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1948         if (efivars->efi_pstore_info.buf) {
1949                 efivars->efi_pstore_info.bufsize = 1024;
1950                 efivars->efi_pstore_info.data = efivars;
1951                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1952                 pstore_register(&efivars->efi_pstore_info);
1953         }
1954
1955         register_filesystem(&efivarfs_type);
1956
1957 out:
1958         kfree(variable_name);
1959
1960         return error;
1961 }
1962 EXPORT_SYMBOL_GPL(register_efivars);
1963
1964 /*
1965  * For now we register the efi subsystem with the firmware subsystem
1966  * and the vars subsystem with the efi subsystem.  In the future, it
1967  * might make sense to split off the efi subsystem into its own
1968  * driver, but for now only efivars will register with it, so just
1969  * include it here.
1970  */
1971
1972 static int __init
1973 efivars_init(void)
1974 {
1975         int error = 0;
1976
1977         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1978                EFIVARS_DATE);
1979
1980         if (!efi_enabled(EFI_RUNTIME_SERVICES))
1981                 return 0;
1982
1983         /* For now we'll register the efi directory at /sys/firmware/efi */
1984         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1985         if (!efi_kobj) {
1986                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1987                 return -ENOMEM;
1988         }
1989
1990         ops.get_variable = efi.get_variable;
1991         ops.set_variable = efi.set_variable;
1992         ops.get_next_variable = efi.get_next_variable;
1993         ops.query_variable_info = efi.query_variable_info;
1994
1995         error = register_efivars(&__efivars, &ops, efi_kobj);
1996         if (error)
1997                 goto err_put;
1998
1999         /* Don't forget the systab entry */
2000         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2001         if (error) {
2002                 printk(KERN_ERR
2003                        "efivars: Sysfs attribute export failed with error %d.\n",
2004                        error);
2005                 goto err_unregister;
2006         }
2007
2008         return 0;
2009
2010 err_unregister:
2011         unregister_efivars(&__efivars);
2012 err_put:
2013         kobject_put(efi_kobj);
2014         return error;
2015 }
2016
2017 static void __exit
2018 efivars_exit(void)
2019 {
2020         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2021                 unregister_efivars(&__efivars);
2022                 kobject_put(efi_kobj);
2023         }
2024 }
2025
2026 module_init(efivars_init);
2027 module_exit(efivars_exit);
2028