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
  81 #include <asm/uaccess.h>
  82
  83 #define EFIVARS_VERSION "0.08"
  84 #define EFIVARS_DATE "2004-May-17"
  85
  86 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  87 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  88 MODULE_LICENSE("GPL");
  89 MODULE_VERSION(EFIVARS_VERSION);
  90
  91 /*
  92  * efivars_lock protects two things:
  93  * 1) efivar_list - adds, removals, reads, writes
  94  * 2) efi.[gs]et_variable() calls.
  95  * It must not be held when creating sysfs entries or calling kmalloc.
  96  * efi.get_next_variable() is only called from efivars_init(),
  97  * which is protected by the BKL, so that path is safe.
  98  */
  99 static DEFINE_SPINLOCK(efivars_lock);
 100 static LIST_HEAD(efivar_list);
 101
 102 /*
 103  * The maximum size of VariableName + Data = 1024
 104  * Therefore, it's reasonable to save that much
 105  * space in each part of the structure,
 106  * and we use a page for reading/writing.
 107  */
 108
 109 struct efi_variable {
 110         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 111         efi_guid_t    VendorGuid;
 112         unsigned long DataSize;
 113         __u8          Data[1024];
 114         efi_status_t  Status;
 115         __u32         Attributes;
 116 } __attribute__((packed));
 117
 118
 119 struct efivar_entry {
 120         struct efi_variable var;
 121         struct list_head list;
 122         struct kobject kobj;
 123 };
 124
 125 struct efivar_attribute {
 126         struct attribute attr;
 127         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 128         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 129 };
 130
 131
 132 #define EFI_ATTR(_name, _mode, _show, _store) \
 133 struct subsys_attribute efi_attr_##_name = { \
 134         .attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
 135         .show = _show, \
 136         .store = _store, \
 137 };
 138
 139 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 140 struct efivar_attribute efivar_attr_##_name = { \
 141         .attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
 142         .show = _show, \
 143         .store = _store, \
 144 };
 145
 146 #define VAR_SUBSYS_ATTR(_name, _mode, _show, _store) \
 147 struct subsys_attribute var_subsys_attr_##_name = { \
 148         .attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
 149         .show = _show, \
 150         .store = _store, \
 151 };
 152
 153 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 154 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 155
 156 /*
 157  * Prototype for sysfs creation function
 158  */
 159 static int
 160 efivar_create_sysfs_entry(unsigned long variable_name_size,
 161                                 efi_char16_t *variable_name,
 162                                 efi_guid_t *vendor_guid);
 163
 164 /* Return the number of unicode characters in data */
 165 static unsigned long
 166 utf8_strlen(efi_char16_t *data, unsigned long maxlength)
 167 {
 168         unsigned long length = 0;
 169
 170         while (*data++ != 0 && length < maxlength)
 171                 length++;
 172         return length;
 173 }
 174
 175 /*
 176  * Return the number of bytes is the length of this string
 177  * Note: this is NOT the same as the number of unicode characters
 178  */
 179 static inline unsigned long
 180 utf8_strsize(efi_char16_t *data, unsigned long maxlength)
 181 {
 182         return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 183 }
 184
 185 static efi_status_t
 186 get_var_data(struct efi_variable *var)
 187 {
 188         efi_status_t status;
 189
 190         spin_lock(&efivars_lock);
 191         var->DataSize = 1024;
 192         status = efi.get_variable(var->VariableName,
 193                                 &var->VendorGuid,
 194                                 &var->Attributes,
 195                                 &var->DataSize,
 196                                 var->Data);
 197         spin_unlock(&efivars_lock);
 198         if (status != EFI_SUCCESS) {
 199                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 200                         status);
 201         }
 202         return status;
 203 }
 204
 205 static ssize_t
 206 efivar_guid_read(struct efivar_entry *entry, char *buf)
 207 {
 208         struct efi_variable *var = &entry->var;
 209         char *str = buf;
 210
 211         if (!entry || !buf)
 212                 return 0;
 213
 214         efi_guid_unparse(&var->VendorGuid, str);
 215         str += strlen(str);
 216         str += sprintf(str, "\n");
 217
 218         return str - buf;
 219 }
 220
 221 static ssize_t
 222 efivar_attr_read(struct efivar_entry *entry, char *buf)
 223 {
 224         struct efi_variable *var = &entry->var;
 225         char *str = buf;
 226         efi_status_t status;
 227
 228         if (!entry || !buf)
 229                 return -EINVAL;
 230
 231         status = get_var_data(var);
 232         if (status != EFI_SUCCESS)
 233                 return -EIO;
 234
 235         if (var->Attributes & 0x1)
 236                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 237         if (var->Attributes & 0x2)
 238                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 239         if (var->Attributes & 0x4)
 240                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 241         return str - buf;
 242 }
 243
 244 static ssize_t
 245 efivar_size_read(struct efivar_entry *entry, char *buf)
 246 {
 247         struct efi_variable *var = &entry->var;
 248         char *str = buf;
 249         efi_status_t status;
 250
 251         if (!entry || !buf)
 252                 return -EINVAL;
 253
 254         status = get_var_data(var);
 255         if (status != EFI_SUCCESS)
 256                 return -EIO;
 257
 258         str += sprintf(str, "0x%lx\n", var->DataSize);
 259         return str - buf;
 260 }
 261
 262 static ssize_t
 263 efivar_data_read(struct efivar_entry *entry, char *buf)
 264 {
 265         struct efi_variable *var = &entry->var;
 266         efi_status_t status;
 267
 268         if (!entry || !buf)
 269                 return -EINVAL;
 270
 271         status = get_var_data(var);
 272         if (status != EFI_SUCCESS)
 273                 return -EIO;
 274
 275         memcpy(buf, var->Data, var->DataSize);
 276         return var->DataSize;
 277 }
 278 /*
 279  * We allow each variable to be edited via rewriting the
 280  * entire efi variable structure.
 281  */
 282 static ssize_t
 283 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 284 {
 285         struct efi_variable *new_var, *var = &entry->var;
 286         efi_status_t status = EFI_NOT_FOUND;
 287
 288         if (count != sizeof(struct efi_variable))
 289                 return -EINVAL;
 290
 291         new_var = (struct efi_variable *)buf;
 292         /*
 293          * If only updating the variable data, then the name
 294          * and guid should remain the same
 295          */
 296         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 297                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 298                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 299                 return -EINVAL;
 300         }
 301
 302         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 303                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 304                 return -EINVAL;
 305         }
 306
 307         spin_lock(&efivars_lock);
 308         status = efi.set_variable(new_var->VariableName,
 309                                         &new_var->VendorGuid,
 310                                         new_var->Attributes,
 311                                         new_var->DataSize,
 312                                         new_var->Data);
 313
 314         spin_unlock(&efivars_lock);
 315
 316         if (status != EFI_SUCCESS) {
 317                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 318                         status);
 319                 return -EIO;
 320         }
 321
 322         memcpy(&entry->var, new_var, count);
 323         return count;
 324 }
 325
 326 static ssize_t
 327 efivar_show_raw(struct efivar_entry *entry, char *buf)
 328 {
 329         struct efi_variable *var = &entry->var;
 330         efi_status_t status;
 331
 332         if (!entry || !buf)
 333                 return 0;
 334
 335         status = get_var_data(var);
 336         if (status != EFI_SUCCESS)
 337                 return -EIO;
 338
 339         memcpy(buf, var, sizeof(*var));
 340         return sizeof(*var);
 341 }
 342
 343 /*
 344  * Generic read/write functions that call the specific functions of
 345  * the atttributes...
 346  */
 347 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 348                                 char *buf)
 349 {
 350         struct efivar_entry *var = to_efivar_entry(kobj);
 351         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 352         ssize_t ret = -EIO;
 353
 354         if (!capable(CAP_SYS_ADMIN))
 355                 return -EACCES;
 356
 357         if (efivar_attr->show) {
 358                 ret = efivar_attr->show(var, buf);
 359         }
 360         return ret;
 361 }
 362
 363 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 364                                 const char *buf, size_t count)
 365 {
 366         struct efivar_entry *var = to_efivar_entry(kobj);
 367         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 368         ssize_t ret = -EIO;
 369
 370         if (!capable(CAP_SYS_ADMIN))
 371                 return -EACCES;
 372
 373         if (efivar_attr->store)
 374                 ret = efivar_attr->store(var, buf, count);
 375
 376         return ret;
 377 }
 378
 379 static struct sysfs_ops efivar_attr_ops = {
 380         .show = efivar_attr_show,
 381         .store = efivar_attr_store,
 382 };
 383
 384 static void efivar_release(struct kobject *kobj)
 385 {
 386         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 387         kfree(var);
 388 }
 389
 390 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 391 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 392 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 393 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 394 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 395
 396 static struct attribute *def_attrs[] = {
 397         &efivar_attr_guid.attr,
 398         &efivar_attr_size.attr,
 399         &efivar_attr_attributes.attr,
 400         &efivar_attr_data.attr,
 401         &efivar_attr_raw_var.attr,
 402         NULL,
 403 };
 404
 405 static struct kobj_type ktype_efivar = {
 406         .release = efivar_release,
 407         .sysfs_ops = &efivar_attr_ops,
 408         .default_attrs = def_attrs,
 409 };
 410
 411 static ssize_t
 412 dummy(struct subsystem *sub, char *buf)
 413 {
 414         return -ENODEV;
 415 }
 416
 417 static inline void
 418 efivar_unregister(struct efivar_entry *var)
 419 {
 420         kobject_unregister(&var->kobj);
 421 }
 422
 423
 424 static ssize_t
 425 efivar_create(struct subsystem *sub, const char *buf, size_t count)
 426 {
 427         struct efi_variable *new_var = (struct efi_variable *)buf;
 428         struct efivar_entry *search_efivar, *n;
 429         unsigned long strsize1, strsize2;
 430         efi_status_t status = EFI_NOT_FOUND;
 431         int found = 0;
 432
 433         if (!capable(CAP_SYS_ADMIN))
 434                 return -EACCES;
 435
 436         spin_lock(&efivars_lock);
 437
 438         /*
 439          * Does this variable already exist?
 440          */
 441         list_for_each_entry_safe(search_efivar, n, &efivar_list, list) {
 442                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
 443                 strsize2 = utf8_strsize(new_var->VariableName, 1024);
 444                 if (strsize1 == strsize2 &&
 445                         !memcmp(&(search_efivar->var.VariableName),
 446                                 new_var->VariableName, strsize1) &&
 447                         !efi_guidcmp(search_efivar->var.VendorGuid,
 448                                 new_var->VendorGuid)) {
 449                         found = 1;
 450                         break;
 451                 }
 452         }
 453         if (found) {
 454                 spin_unlock(&efivars_lock);
 455                 return -EINVAL;
 456         }
 457
 458         /* now *really* create the variable via EFI */
 459         status = efi.set_variable(new_var->VariableName,
 460                         &new_var->VendorGuid,
 461                         new_var->Attributes,
 462                         new_var->DataSize,
 463                         new_var->Data);
 464
 465         if (status != EFI_SUCCESS) {
 466                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 467                         status);
 468                 spin_unlock(&efivars_lock);
 469                 return -EIO;
 470         }
 471         spin_unlock(&efivars_lock);
 472
 473         /* Create the entry in sysfs.  Locking is not required here */
 474         status = efivar_create_sysfs_entry(utf8_strsize(new_var->VariableName,
 475                         1024), new_var->VariableName, &new_var->VendorGuid);
 476         if (status) {
 477                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 478         }
 479         return count;
 480 }
 481
 482 static ssize_t
 483 efivar_delete(struct subsystem *sub, const char *buf, size_t count)
 484 {
 485         struct efi_variable *del_var = (struct efi_variable *)buf;
 486         struct efivar_entry *search_efivar, *n;
 487         unsigned long strsize1, strsize2;
 488         efi_status_t status = EFI_NOT_FOUND;
 489         int found = 0;
 490
 491         if (!capable(CAP_SYS_ADMIN))
 492                 return -EACCES;
 493
 494         spin_lock(&efivars_lock);
 495
 496         /*
 497          * Does this variable already exist?
 498          */
 499         list_for_each_entry_safe(search_efivar, n, &efivar_list, list) {
 500                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
 501                 strsize2 = utf8_strsize(del_var->VariableName, 1024);
 502                 if (strsize1 == strsize2 &&
 503                         !memcmp(&(search_efivar->var.VariableName),
 504                                 del_var->VariableName, strsize1) &&
 505                         !efi_guidcmp(search_efivar->var.VendorGuid,
 506                                 del_var->VendorGuid)) {
 507                         found = 1;
 508                         break;
 509                 }
 510         }
 511         if (!found) {
 512                 spin_unlock(&efivars_lock);
 513                 return -EINVAL;
 514         }
 515         /* force the Attributes/DataSize to 0 to ensure deletion */
 516         del_var->Attributes = 0;
 517         del_var->DataSize = 0;
 518
 519         status = efi.set_variable(del_var->VariableName,
 520                         &del_var->VendorGuid,
 521                         del_var->Attributes,
 522                         del_var->DataSize,
 523                         del_var->Data);
 524
 525         if (status != EFI_SUCCESS) {
 526                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 527                         status);
 528                 spin_unlock(&efivars_lock);
 529                 return -EIO;
 530         }
 531         list_del(&search_efivar->list);
 532         /* We need to release this lock before unregistering. */
 533         spin_unlock(&efivars_lock);
 534         efivar_unregister(search_efivar);
 535
 536         /* It's dead Jim.... */
 537         return count;
 538 }
 539
 540 static VAR_SUBSYS_ATTR(new_var, 0200, dummy, efivar_create);
 541 static VAR_SUBSYS_ATTR(del_var, 0200, dummy, efivar_delete);
 542
 543 static struct subsys_attribute *var_subsys_attrs[] = {
 544         &var_subsys_attr_new_var,
 545         &var_subsys_attr_del_var,
 546         NULL,
 547 };
 548
 549 /*
 550  * Let's not leave out systab information that snuck into
 551  * the efivars driver
 552  */
 553 static ssize_t
 554 systab_read(struct subsystem *entry, char *buf)
 555 {
 556         char *str = buf;
 557
 558         if (!entry || !buf)
 559                 return -EINVAL;
 560
 561         if (efi.mps != EFI_INVALID_TABLE_ADDR)
 562                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 563         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 564                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 565         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 566                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 567         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 568                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 569         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 570                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 571         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 572                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 573         if (efi.uga != EFI_INVALID_TABLE_ADDR)
 574                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 575
 576         return str - buf;
 577 }
 578
 579 static EFI_ATTR(systab, 0400, systab_read, NULL);
 580
 581 static struct subsys_attribute *efi_subsys_attrs[] = {
 582         &efi_attr_systab,
 583         NULL,   /* maybe more in the future? */
 584 };
 585
 586 static decl_subsys(vars, &ktype_efivar, NULL);
 587 static decl_subsys(efi, NULL, NULL);
 588
 589 /*
 590  * efivar_create_sysfs_entry()
 591  * Requires:
 592  *    variable_name_size = number of bytes required to hold
 593  *                         variable_name (not counting the NULL
 594  *                         character at the end.
 595  *    efivars_lock is not held on entry or exit.
 596  * Returns 1 on failure, 0 on success
 597  */
 598 static int
 599 efivar_create_sysfs_entry(unsigned long variable_name_size,
 600                         efi_char16_t *variable_name,
 601                         efi_guid_t *vendor_guid)
 602 {
 603         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 604         char *short_name;
 605         struct efivar_entry *new_efivar;
 606
 607         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 608         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 609
 610         if (!short_name || !new_efivar)  {
 611                 kfree(short_name);
 612                 kfree(new_efivar);
 613                 return 1;
 614         }
 615
 616         memcpy(new_efivar->var.VariableName, variable_name,
 617                 variable_name_size);
 618         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
 619
 620         /* Convert Unicode to normal chars (assume top bits are 0),
 621            ala UTF-8 */
 622         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
 623                 short_name[i] = variable_name[i] & 0xFF;
 624         }
 625         /* This is ugly, but necessary to separate one vendor's
 626            private variables from another's.         */
 627
 628         *(short_name + strlen(short_name)) = '-';
 629         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
 630
 631         kobject_set_name(&new_efivar->kobj, "%s", short_name);
 632         kobj_set_kset_s(new_efivar, vars_subsys);
 633         i = kobject_register(&new_efivar->kobj);
 634         if (i) {
 635                 kfree(short_name);
 636                 kfree(new_efivar);
 637                 return 1;
 638         }
 639
 640         kfree(short_name);
 641         short_name = NULL;
 642
 643         spin_lock(&efivars_lock);
 644         list_add(&new_efivar->list, &efivar_list);
 645         spin_unlock(&efivars_lock);
 646
 647         return 0;
 648 }
 649 /*
 650  * For now we register the efi subsystem with the firmware subsystem
 651  * and the vars subsystem with the efi subsystem.  In the future, it
 652  * might make sense to split off the efi subsystem into its own
 653  * driver, but for now only efivars will register with it, so just
 654  * include it here.
 655  */
 656
 657 static int __init
 658 efivars_init(void)
 659 {
 660         efi_status_t status = EFI_NOT_FOUND;
 661         efi_guid_t vendor_guid;
 662         efi_char16_t *variable_name;
 663         struct subsys_attribute *attr;
 664         unsigned long variable_name_size = 1024;
 665         int i, error = 0;
 666
 667         if (!efi_enabled)
 668                 return -ENODEV;
 669
 670         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
 671         if (!variable_name) {
 672                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
 673                 return -ENOMEM;
 674         }
 675
 676         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 677                EFIVARS_DATE);
 678
 679         /*
 680          * For now we'll register the efi subsys within this driver
 681          */
 682
 683         error = firmware_register(&efi_subsys);
 684
 685         if (error) {
 686                 printk(KERN_ERR "efivars: Firmware registration failed with error %d.\n", error);
 687                 goto out_free;
 688         }
 689
 690         kset_set_kset_s(&vars_subsys, efi_subsys);
 691
 692         error = subsystem_register(&vars_subsys);
 693
 694         if (error) {
 695                 printk(KERN_ERR "efivars: Subsystem registration failed with error %d.\n", error);
 696                 goto out_firmware_unregister;
 697         }
 698
 699         /*
 700          * Per EFI spec, the maximum storage allocated for both
 701          * the variable name and variable data is 1024 bytes.
 702          */
 703
 704         do {
 705                 variable_name_size = 1024;
 706
 707                 status = efi.get_next_variable(&variable_name_size,
 708                                                 variable_name,
 709                                                 &vendor_guid);
 710                 switch (status) {
 711                 case EFI_SUCCESS:
 712                         efivar_create_sysfs_entry(variable_name_size,
 713                                                         variable_name,
 714                                                         &vendor_guid);
 715                         break;
 716                 case EFI_NOT_FOUND:
 717                         break;
 718                 default:
 719                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
 720                                 status);
 721                         status = EFI_NOT_FOUND;
 722                         break;
 723                 }
 724         } while (status != EFI_NOT_FOUND);
 725
 726         /*
 727          * Now add attributes to allow creation of new vars
 728          * and deletion of existing ones...
 729          */
 730
 731         for (i = 0; (attr = var_subsys_attrs[i]) && !error; i++) {
 732                 if (attr->show && attr->store)
 733                         error = subsys_create_file(&vars_subsys, attr);
 734         }
 735
 736         /* Don't forget the systab entry */
 737
 738         for (i = 0; (attr = efi_subsys_attrs[i]) && !error; i++) {
 739                 if (attr->show)
 740                         error = subsys_create_file(&efi_subsys, attr);
 741         }
 742
 743         if (error)
 744                 printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error);
 745         else
 746                 goto out_free;
 747
 748         subsystem_unregister(&vars_subsys);
 749
 750 out_firmware_unregister:
 751         firmware_unregister(&efi_subsys);
 752
 753 out_free:
 754         kfree(variable_name);
 755
 756         return error;
 757 }
 758
 759 static void __exit
 760 efivars_exit(void)
 761 {
 762         struct efivar_entry *entry, *n;
 763
 764         list_for_each_entry_safe(entry, n, &efivar_list, list) {
 765                 spin_lock(&efivars_lock);
 766                 list_del(&entry->list);
 767                 spin_unlock(&efivars_lock);
 768                 efivar_unregister(entry);
 769         }
 770
 771         subsystem_unregister(&vars_subsys);
 772         firmware_unregister(&efi_subsys);
 773 }
 774
 775 module_init(efivars_init);
 776 module_exit(efivars_exit);
 777