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
  82 #include <asm/uaccess.h>
  83
  84 #define EFIVARS_VERSION "0.08"
  85 #define EFIVARS_DATE "2004-May-17"
  86
  87 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  88 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  89 MODULE_LICENSE("GPL");
  90 MODULE_VERSION(EFIVARS_VERSION);
  91
  92 /*
  93  * efivars_lock protects two things:
  94  * 1) efivar_list - adds, removals, reads, writes
  95  * 2) efi.[gs]et_variable() calls.
  96  * It must not be held when creating sysfs entries or calling kmalloc.
  97  * efi.get_next_variable() is only called from efivars_init(),
  98  * which is protected by the BKL, so that path is safe.
  99  */
 100 static DEFINE_SPINLOCK(efivars_lock);
 101 static LIST_HEAD(efivar_list);
 102
 103 /*
 104  * The maximum size of VariableName + Data = 1024
 105  * Therefore, it's reasonable to save that much
 106  * space in each part of the structure,
 107  * and we use a page for reading/writing.
 108  */
 109
 110 struct efi_variable {
 111         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 112         efi_guid_t    VendorGuid;
 113         unsigned long DataSize;
 114         __u8          Data[1024];
 115         efi_status_t  Status;
 116         __u32         Attributes;
 117 } __attribute__((packed));
 118
 119
 120 struct efivar_entry {
 121         struct efi_variable var;
 122         struct list_head list;
 123         struct kobject kobj;
 124 };
 125
 126 struct efivar_attribute {
 127         struct attribute attr;
 128         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 129         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 130 };
 131
 132
 133 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 134 struct efivar_attribute efivar_attr_##_name = { \
 135         .attr = {.name = __stringify(_name), .mode = _mode}, \
 136         .show = _show, \
 137         .store = _store, \
 138 };
 139
 140 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 141 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 142
 143 /*
 144  * Prototype for sysfs creation function
 145  */
 146 static int
 147 efivar_create_sysfs_entry(unsigned long variable_name_size,
 148                                 efi_char16_t *variable_name,
 149                                 efi_guid_t *vendor_guid);
 150
 151 /* Return the number of unicode characters in data */
 152 static unsigned long
 153 utf8_strlen(efi_char16_t *data, unsigned long maxlength)
 154 {
 155         unsigned long length = 0;
 156
 157         while (*data++ != 0 && length < maxlength)
 158                 length++;
 159         return length;
 160 }
 161
 162 /*
 163  * Return the number of bytes is the length of this string
 164  * Note: this is NOT the same as the number of unicode characters
 165  */
 166 static inline unsigned long
 167 utf8_strsize(efi_char16_t *data, unsigned long maxlength)
 168 {
 169         return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 170 }
 171
 172 static efi_status_t
 173 get_var_data(struct efi_variable *var)
 174 {
 175         efi_status_t status;
 176
 177         spin_lock(&efivars_lock);
 178         var->DataSize = 1024;
 179         status = efi.get_variable(var->VariableName,
 180                                 &var->VendorGuid,
 181                                 &var->Attributes,
 182                                 &var->DataSize,
 183                                 var->Data);
 184         spin_unlock(&efivars_lock);
 185         if (status != EFI_SUCCESS) {
 186                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 187                         status);
 188         }
 189         return status;
 190 }
 191
 192 static ssize_t
 193 efivar_guid_read(struct efivar_entry *entry, char *buf)
 194 {
 195         struct efi_variable *var = &entry->var;
 196         char *str = buf;
 197
 198         if (!entry || !buf)
 199                 return 0;
 200
 201         efi_guid_unparse(&var->VendorGuid, str);
 202         str += strlen(str);
 203         str += sprintf(str, "\n");
 204
 205         return str - buf;
 206 }
 207
 208 static ssize_t
 209 efivar_attr_read(struct efivar_entry *entry, char *buf)
 210 {
 211         struct efi_variable *var = &entry->var;
 212         char *str = buf;
 213         efi_status_t status;
 214
 215         if (!entry || !buf)
 216                 return -EINVAL;
 217
 218         status = get_var_data(var);
 219         if (status != EFI_SUCCESS)
 220                 return -EIO;
 221
 222         if (var->Attributes & 0x1)
 223                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 224         if (var->Attributes & 0x2)
 225                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 226         if (var->Attributes & 0x4)
 227                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 228         return str - buf;
 229 }
 230
 231 static ssize_t
 232 efivar_size_read(struct efivar_entry *entry, char *buf)
 233 {
 234         struct efi_variable *var = &entry->var;
 235         char *str = buf;
 236         efi_status_t status;
 237
 238         if (!entry || !buf)
 239                 return -EINVAL;
 240
 241         status = get_var_data(var);
 242         if (status != EFI_SUCCESS)
 243                 return -EIO;
 244
 245         str += sprintf(str, "0x%lx\n", var->DataSize);
 246         return str - buf;
 247 }
 248
 249 static ssize_t
 250 efivar_data_read(struct efivar_entry *entry, char *buf)
 251 {
 252         struct efi_variable *var = &entry->var;
 253         efi_status_t status;
 254
 255         if (!entry || !buf)
 256                 return -EINVAL;
 257
 258         status = get_var_data(var);
 259         if (status != EFI_SUCCESS)
 260                 return -EIO;
 261
 262         memcpy(buf, var->Data, var->DataSize);
 263         return var->DataSize;
 264 }
 265 /*
 266  * We allow each variable to be edited via rewriting the
 267  * entire efi variable structure.
 268  */
 269 static ssize_t
 270 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 271 {
 272         struct efi_variable *new_var, *var = &entry->var;
 273         efi_status_t status = EFI_NOT_FOUND;
 274
 275         if (count != sizeof(struct efi_variable))
 276                 return -EINVAL;
 277
 278         new_var = (struct efi_variable *)buf;
 279         /*
 280          * If only updating the variable data, then the name
 281          * and guid should remain the same
 282          */
 283         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 284                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 285                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 286                 return -EINVAL;
 287         }
 288
 289         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 290                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 291                 return -EINVAL;
 292         }
 293
 294         spin_lock(&efivars_lock);
 295         status = efi.set_variable(new_var->VariableName,
 296                                         &new_var->VendorGuid,
 297                                         new_var->Attributes,
 298                                         new_var->DataSize,
 299                                         new_var->Data);
 300
 301         spin_unlock(&efivars_lock);
 302
 303         if (status != EFI_SUCCESS) {
 304                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 305                         status);
 306                 return -EIO;
 307         }
 308
 309         memcpy(&entry->var, new_var, count);
 310         return count;
 311 }
 312
 313 static ssize_t
 314 efivar_show_raw(struct efivar_entry *entry, char *buf)
 315 {
 316         struct efi_variable *var = &entry->var;
 317         efi_status_t status;
 318
 319         if (!entry || !buf)
 320                 return 0;
 321
 322         status = get_var_data(var);
 323         if (status != EFI_SUCCESS)
 324                 return -EIO;
 325
 326         memcpy(buf, var, sizeof(*var));
 327         return sizeof(*var);
 328 }
 329
 330 /*
 331  * Generic read/write functions that call the specific functions of
 332  * the atttributes...
 333  */
 334 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 335                                 char *buf)
 336 {
 337         struct efivar_entry *var = to_efivar_entry(kobj);
 338         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 339         ssize_t ret = -EIO;
 340
 341         if (!capable(CAP_SYS_ADMIN))
 342                 return -EACCES;
 343
 344         if (efivar_attr->show) {
 345                 ret = efivar_attr->show(var, buf);
 346         }
 347         return ret;
 348 }
 349
 350 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 351                                 const char *buf, size_t count)
 352 {
 353         struct efivar_entry *var = to_efivar_entry(kobj);
 354         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 355         ssize_t ret = -EIO;
 356
 357         if (!capable(CAP_SYS_ADMIN))
 358                 return -EACCES;
 359
 360         if (efivar_attr->store)
 361                 ret = efivar_attr->store(var, buf, count);
 362
 363         return ret;
 364 }
 365
 366 static const struct sysfs_ops efivar_attr_ops = {
 367         .show = efivar_attr_show,
 368         .store = efivar_attr_store,
 369 };
 370
 371 static void efivar_release(struct kobject *kobj)
 372 {
 373         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 374         kfree(var);
 375 }
 376
 377 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 378 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 379 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 380 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 381 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 382
 383 static struct attribute *def_attrs[] = {
 384         &efivar_attr_guid.attr,
 385         &efivar_attr_size.attr,
 386         &efivar_attr_attributes.attr,
 387         &efivar_attr_data.attr,
 388         &efivar_attr_raw_var.attr,
 389         NULL,
 390 };
 391
 392 static struct kobj_type efivar_ktype = {
 393         .release = efivar_release,
 394         .sysfs_ops = &efivar_attr_ops,
 395         .default_attrs = def_attrs,
 396 };
 397
 398 static inline void
 399 efivar_unregister(struct efivar_entry *var)
 400 {
 401         kobject_put(&var->kobj);
 402 }
 403
 404
 405 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 406                              struct bin_attribute *bin_attr,
 407                              char *buf, loff_t pos, size_t count)
 408 {
 409         struct efi_variable *new_var = (struct efi_variable *)buf;
 410         struct efivar_entry *search_efivar, *n;
 411         unsigned long strsize1, strsize2;
 412         efi_status_t status = EFI_NOT_FOUND;
 413         int found = 0;
 414
 415         if (!capable(CAP_SYS_ADMIN))
 416                 return -EACCES;
 417
 418         spin_lock(&efivars_lock);
 419
 420         /*
 421          * Does this variable already exist?
 422          */
 423         list_for_each_entry_safe(search_efivar, n, &efivar_list, list) {
 424                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
 425                 strsize2 = utf8_strsize(new_var->VariableName, 1024);
 426                 if (strsize1 == strsize2 &&
 427                         !memcmp(&(search_efivar->var.VariableName),
 428                                 new_var->VariableName, strsize1) &&
 429                         !efi_guidcmp(search_efivar->var.VendorGuid,
 430                                 new_var->VendorGuid)) {
 431                         found = 1;
 432                         break;
 433                 }
 434         }
 435         if (found) {
 436                 spin_unlock(&efivars_lock);
 437                 return -EINVAL;
 438         }
 439
 440         /* now *really* create the variable via EFI */
 441         status = efi.set_variable(new_var->VariableName,
 442                         &new_var->VendorGuid,
 443                         new_var->Attributes,
 444                         new_var->DataSize,
 445                         new_var->Data);
 446
 447         if (status != EFI_SUCCESS) {
 448                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 449                         status);
 450                 spin_unlock(&efivars_lock);
 451                 return -EIO;
 452         }
 453         spin_unlock(&efivars_lock);
 454
 455         /* Create the entry in sysfs.  Locking is not required here */
 456         status = efivar_create_sysfs_entry(utf8_strsize(new_var->VariableName,
 457                         1024), new_var->VariableName, &new_var->VendorGuid);
 458         if (status) {
 459                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 460         }
 461         return count;
 462 }
 463
 464 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 465                              struct bin_attribute *bin_attr,
 466                              char *buf, loff_t pos, size_t count)
 467 {
 468         struct efi_variable *del_var = (struct efi_variable *)buf;
 469         struct efivar_entry *search_efivar, *n;
 470         unsigned long strsize1, strsize2;
 471         efi_status_t status = EFI_NOT_FOUND;
 472         int found = 0;
 473
 474         if (!capable(CAP_SYS_ADMIN))
 475                 return -EACCES;
 476
 477         spin_lock(&efivars_lock);
 478
 479         /*
 480          * Does this variable already exist?
 481          */
 482         list_for_each_entry_safe(search_efivar, n, &efivar_list, list) {
 483                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
 484                 strsize2 = utf8_strsize(del_var->VariableName, 1024);
 485                 if (strsize1 == strsize2 &&
 486                         !memcmp(&(search_efivar->var.VariableName),
 487                                 del_var->VariableName, strsize1) &&
 488                         !efi_guidcmp(search_efivar->var.VendorGuid,
 489                                 del_var->VendorGuid)) {
 490                         found = 1;
 491                         break;
 492                 }
 493         }
 494         if (!found) {
 495                 spin_unlock(&efivars_lock);
 496                 return -EINVAL;
 497         }
 498         /* force the Attributes/DataSize to 0 to ensure deletion */
 499         del_var->Attributes = 0;
 500         del_var->DataSize = 0;
 501
 502         status = efi.set_variable(del_var->VariableName,
 503                         &del_var->VendorGuid,
 504                         del_var->Attributes,
 505                         del_var->DataSize,
 506                         del_var->Data);
 507
 508         if (status != EFI_SUCCESS) {
 509                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 510                         status);
 511                 spin_unlock(&efivars_lock);
 512                 return -EIO;
 513         }
 514         list_del(&search_efivar->list);
 515         /* We need to release this lock before unregistering. */
 516         spin_unlock(&efivars_lock);
 517         efivar_unregister(search_efivar);
 518
 519         /* It's dead Jim.... */
 520         return count;
 521 }
 522
 523 static struct bin_attribute var_subsys_attr_new_var = {
 524         .attr = {.name = "new_var", .mode = 0200},
 525         .write = efivar_create,
 526 };
 527
 528 static struct bin_attribute var_subsys_attr_del_var = {
 529         .attr = {.name = "del_var", .mode = 0200},
 530         .write = efivar_delete,
 531 };
 532
 533 /*
 534  * Let's not leave out systab information that snuck into
 535  * the efivars driver
 536  */
 537 static ssize_t systab_show(struct kobject *kobj,
 538                            struct kobj_attribute *attr, char *buf)
 539 {
 540         char *str = buf;
 541
 542         if (!kobj || !buf)
 543                 return -EINVAL;
 544
 545         if (efi.mps != EFI_INVALID_TABLE_ADDR)
 546                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 547         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 548                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 549         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 550                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 551         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 552                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 553         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 554                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 555         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 556                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 557         if (efi.uga != EFI_INVALID_TABLE_ADDR)
 558                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 559
 560         return str - buf;
 561 }
 562
 563 static struct kobj_attribute efi_attr_systab =
 564                         __ATTR(systab, 0400, systab_show, NULL);
 565
 566 static struct attribute *efi_subsys_attrs[] = {
 567         &efi_attr_systab.attr,
 568         NULL,   /* maybe more in the future? */
 569 };
 570
 571 static struct attribute_group efi_subsys_attr_group = {
 572         .attrs = efi_subsys_attrs,
 573 };
 574
 575
 576 static struct kset *vars_kset;
 577 static struct kobject *efi_kobj;
 578
 579 /*
 580  * efivar_create_sysfs_entry()
 581  * Requires:
 582  *    variable_name_size = number of bytes required to hold
 583  *                         variable_name (not counting the NULL
 584  *                         character at the end.
 585  *    efivars_lock is not held on entry or exit.
 586  * Returns 1 on failure, 0 on success
 587  */
 588 static int
 589 efivar_create_sysfs_entry(unsigned long variable_name_size,
 590                         efi_char16_t *variable_name,
 591                         efi_guid_t *vendor_guid)
 592 {
 593         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 594         char *short_name;
 595         struct efivar_entry *new_efivar;
 596
 597         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 598         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 599
 600         if (!short_name || !new_efivar)  {
 601                 kfree(short_name);
 602                 kfree(new_efivar);
 603                 return 1;
 604         }
 605
 606         memcpy(new_efivar->var.VariableName, variable_name,
 607                 variable_name_size);
 608         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
 609
 610         /* Convert Unicode to normal chars (assume top bits are 0),
 611            ala UTF-8 */
 612         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
 613                 short_name[i] = variable_name[i] & 0xFF;
 614         }
 615         /* This is ugly, but necessary to separate one vendor's
 616            private variables from another's.         */
 617
 618         *(short_name + strlen(short_name)) = '-';
 619         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
 620
 621         new_efivar->kobj.kset = vars_kset;
 622         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
 623                                  "%s", short_name);
 624         if (i) {
 625                 kfree(short_name);
 626                 kfree(new_efivar);
 627                 return 1;
 628         }
 629
 630         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
 631         kfree(short_name);
 632         short_name = NULL;
 633
 634         spin_lock(&efivars_lock);
 635         list_add(&new_efivar->list, &efivar_list);
 636         spin_unlock(&efivars_lock);
 637
 638         return 0;
 639 }
 640 /*
 641  * For now we register the efi subsystem with the firmware subsystem
 642  * and the vars subsystem with the efi subsystem.  In the future, it
 643  * might make sense to split off the efi subsystem into its own
 644  * driver, but for now only efivars will register with it, so just
 645  * include it here.
 646  */
 647
 648 static int __init
 649 efivars_init(void)
 650 {
 651         efi_status_t status = EFI_NOT_FOUND;
 652         efi_guid_t vendor_guid;
 653         efi_char16_t *variable_name;
 654         unsigned long variable_name_size = 1024;
 655         int error = 0;
 656
 657         if (!efi_enabled)
 658                 return -ENODEV;
 659
 660         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
 661         if (!variable_name) {
 662                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
 663                 return -ENOMEM;
 664         }
 665
 666         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 667                EFIVARS_DATE);
 668
 669         /* For now we'll register the efi directory at /sys/firmware/efi */
 670         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
 671         if (!efi_kobj) {
 672                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
 673                 error = -ENOMEM;
 674                 goto out_free;
 675         }
 676
 677         vars_kset = kset_create_and_add("vars", NULL, efi_kobj);
 678         if (!vars_kset) {
 679                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 680                 error = -ENOMEM;
 681                 goto out_firmware_unregister;
 682         }
 683
 684         /*
 685          * Per EFI spec, the maximum storage allocated for both
 686          * the variable name and variable data is 1024 bytes.
 687          */
 688
 689         do {
 690                 variable_name_size = 1024;
 691
 692                 status = efi.get_next_variable(&variable_name_size,
 693                                                 variable_name,
 694                                                 &vendor_guid);
 695                 switch (status) {
 696                 case EFI_SUCCESS:
 697                         efivar_create_sysfs_entry(variable_name_size,
 698                                                         variable_name,
 699                                                         &vendor_guid);
 700                         break;
 701                 case EFI_NOT_FOUND:
 702                         break;
 703                 default:
 704                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
 705                                 status);
 706                         status = EFI_NOT_FOUND;
 707                         break;
 708                 }
 709         } while (status != EFI_NOT_FOUND);
 710
 711         /*
 712          * Now add attributes to allow creation of new vars
 713          * and deletion of existing ones...
 714          */
 715         error = sysfs_create_bin_file(&vars_kset->kobj,
 716                                       &var_subsys_attr_new_var);
 717         if (error)
 718                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
 719                         " due to error %d\n", error);
 720         error = sysfs_create_bin_file(&vars_kset->kobj,
 721                                       &var_subsys_attr_del_var);
 722         if (error)
 723                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
 724                         " due to error %d\n", error);
 725
 726         /* Don't forget the systab entry */
 727         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
 728         if (error)
 729                 printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error);
 730         else
 731                 goto out_free;
 732
 733         kset_unregister(vars_kset);
 734
 735 out_firmware_unregister:
 736         kobject_put(efi_kobj);
 737
 738 out_free:
 739         kfree(variable_name);
 740
 741         return error;
 742 }
 743
 744 static void __exit
 745 efivars_exit(void)
 746 {
 747         struct efivar_entry *entry, *n;
 748
 749         list_for_each_entry_safe(entry, n, &efivar_list, list) {
 750                 spin_lock(&efivars_lock);
 751                 list_del(&entry->list);
 752                 spin_unlock(&efivars_lock);
 753                 efivar_unregister(entry);
 754         }
 755
 756         kset_unregister(vars_kset);
 757         kobject_put(efi_kobj);
 758 }
 759
 760 module_init(efivars_init);
 761 module_exit(efivars_exit);
 762