drivers/firmware/efivars.c

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