drivers/firmware/efivars.c

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