drivers/firmware/efi/efivars.c

   1 /*
   2  * Originally from 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/efi.h>
  69 #include <linux/module.h>
  70 #include <linux/slab.h>
  71 #include <linux/ucs2_string.h>
  72
  73 #define EFIVARS_VERSION "0.08"
  74 #define EFIVARS_DATE "2004-May-17"
  75
  76 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  77 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  78 MODULE_LICENSE("GPL");
  79 MODULE_VERSION(EFIVARS_VERSION);
  80
  81 LIST_HEAD(efivar_sysfs_list);
  82 EXPORT_SYMBOL_GPL(efivar_sysfs_list);
  83
  84 static struct kset *efivars_kset;
  85
  86 static struct bin_attribute *efivars_new_var;
  87 static struct bin_attribute *efivars_del_var;
  88
  89 struct efivar_attribute {
  90         struct attribute attr;
  91         ssize_t (*show) (struct efivar_entry *entry, char *buf);
  92         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
  93 };
  94
  95 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
  96 struct efivar_attribute efivar_attr_##_name = { \
  97         .attr = {.name = __stringify(_name), .mode = _mode}, \
  98         .show = _show, \
  99         .store = _store, \
 100 };
 101
 102 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 103 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 104
 105 /*
 106  * Prototype for sysfs creation function
 107  */
 108 static int
 109 efivar_create_sysfs_entry(struct efivar_entry *new_var);
 110
 111 static ssize_t
 112 efivar_guid_read(struct efivar_entry *entry, char *buf)
 113 {
 114         struct efi_variable *var = &entry->var;
 115         char *str = buf;
 116
 117         if (!entry || !buf)
 118                 return 0;
 119
 120         efi_guid_unparse(&var->VendorGuid, str);
 121         str += strlen(str);
 122         str += sprintf(str, "\n");
 123
 124         return str - buf;
 125 }
 126
 127 static ssize_t
 128 efivar_attr_read(struct efivar_entry *entry, char *buf)
 129 {
 130         struct efi_variable *var = &entry->var;
 131         char *str = buf;
 132
 133         if (!entry || !buf)
 134                 return -EINVAL;
 135
 136         var->DataSize = 1024;
 137         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 138                 return -EIO;
 139
 140         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 141                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 142         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 143                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 144         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 145                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 146         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 147                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 148         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 149                 str += sprintf(str,
 150                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 151         if (var->Attributes &
 152                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 153                 str += sprintf(str,
 154                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 155         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 156                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 157         return str - buf;
 158 }
 159
 160 static ssize_t
 161 efivar_size_read(struct efivar_entry *entry, char *buf)
 162 {
 163         struct efi_variable *var = &entry->var;
 164         char *str = buf;
 165
 166         if (!entry || !buf)
 167                 return -EINVAL;
 168
 169         var->DataSize = 1024;
 170         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 171                 return -EIO;
 172
 173         str += sprintf(str, "0x%lx\n", var->DataSize);
 174         return str - buf;
 175 }
 176
 177 static ssize_t
 178 efivar_data_read(struct efivar_entry *entry, char *buf)
 179 {
 180         struct efi_variable *var = &entry->var;
 181
 182         if (!entry || !buf)
 183                 return -EINVAL;
 184
 185         var->DataSize = 1024;
 186         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 187                 return -EIO;
 188
 189         memcpy(buf, var->Data, var->DataSize);
 190         return var->DataSize;
 191 }
 192 /*
 193  * We allow each variable to be edited via rewriting the
 194  * entire efi variable structure.
 195  */
 196 static ssize_t
 197 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 198 {
 199         struct efi_variable *new_var, *var = &entry->var;
 200         int err;
 201
 202         if (count != sizeof(struct efi_variable))
 203                 return -EINVAL;
 204
 205         new_var = (struct efi_variable *)buf;
 206         /*
 207          * If only updating the variable data, then the name
 208          * and guid should remain the same
 209          */
 210         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 211                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 212                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 213                 return -EINVAL;
 214         }
 215
 216         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 217                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 218                 return -EINVAL;
 219         }
 220
 221         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 222             efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) {
 223                 printk(KERN_ERR "efivars: Malformed variable content\n");
 224                 return -EINVAL;
 225         }
 226
 227         memcpy(&entry->var, new_var, count);
 228
 229         err = efivar_entry_set(entry, new_var->Attributes,
 230                                new_var->DataSize, new_var->Data, false);
 231         if (err) {
 232                 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
 233                 return -EIO;
 234         }
 235
 236         return count;
 237 }
 238
 239 static ssize_t
 240 efivar_show_raw(struct efivar_entry *entry, char *buf)
 241 {
 242         struct efi_variable *var = &entry->var;
 243
 244         if (!entry || !buf)
 245                 return 0;
 246
 247         var->DataSize = 1024;
 248         if (efivar_entry_get(entry, &entry->var.Attributes,
 249                              &entry->var.DataSize, entry->var.Data))
 250                 return -EIO;
 251
 252         memcpy(buf, var, sizeof(*var));
 253
 254         return sizeof(*var);
 255 }
 256
 257 /*
 258  * Generic read/write functions that call the specific functions of
 259  * the attributes...
 260  */
 261 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 262                                 char *buf)
 263 {
 264         struct efivar_entry *var = to_efivar_entry(kobj);
 265         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 266         ssize_t ret = -EIO;
 267
 268         if (!capable(CAP_SYS_ADMIN))
 269                 return -EACCES;
 270
 271         if (efivar_attr->show) {
 272                 ret = efivar_attr->show(var, buf);
 273         }
 274         return ret;
 275 }
 276
 277 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 278                                 const char *buf, size_t count)
 279 {
 280         struct efivar_entry *var = to_efivar_entry(kobj);
 281         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 282         ssize_t ret = -EIO;
 283
 284         if (!capable(CAP_SYS_ADMIN))
 285                 return -EACCES;
 286
 287         if (efivar_attr->store)
 288                 ret = efivar_attr->store(var, buf, count);
 289
 290         return ret;
 291 }
 292
 293 static const struct sysfs_ops efivar_attr_ops = {
 294         .show = efivar_attr_show,
 295         .store = efivar_attr_store,
 296 };
 297
 298 static void efivar_release(struct kobject *kobj)
 299 {
 300         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 301         kfree(var);
 302 }
 303
 304 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 305 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 306 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 307 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 308 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 309
 310 static struct attribute *def_attrs[] = {
 311         &efivar_attr_guid.attr,
 312         &efivar_attr_size.attr,
 313         &efivar_attr_attributes.attr,
 314         &efivar_attr_data.attr,
 315         &efivar_attr_raw_var.attr,
 316         NULL,
 317 };
 318
 319 static struct kobj_type efivar_ktype = {
 320         .release = efivar_release,
 321         .sysfs_ops = &efivar_attr_ops,
 322         .default_attrs = def_attrs,
 323 };
 324
 325 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 326                              struct bin_attribute *bin_attr,
 327                              char *buf, loff_t pos, size_t count)
 328 {
 329         struct efi_variable *new_var = (struct efi_variable *)buf;
 330         struct efivar_entry *new_entry;
 331         int err;
 332
 333         if (!capable(CAP_SYS_ADMIN))
 334                 return -EACCES;
 335
 336         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 337             efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) {
 338                 printk(KERN_ERR "efivars: Malformed variable content\n");
 339                 return -EINVAL;
 340         }
 341
 342         new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
 343         if (!new_entry)
 344                 return -ENOMEM;
 345
 346         memcpy(&new_entry->var, new_var, sizeof(*new_var));
 347
 348         err = efivar_entry_set(new_entry, new_var->Attributes, new_var->DataSize,
 349                                new_var->Data, &efivar_sysfs_list);
 350         if (err) {
 351                 if (err == -EEXIST)
 352                         err = -EINVAL;
 353                 goto out;
 354         }
 355
 356         if (efivar_create_sysfs_entry(new_entry)) {
 357                 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
 358                 kfree(new_entry);
 359         }
 360         return count;
 361
 362 out:
 363         kfree(new_entry);
 364         return err;
 365 }
 366
 367 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 368                              struct bin_attribute *bin_attr,
 369                              char *buf, loff_t pos, size_t count)
 370 {
 371         struct efi_variable *del_var = (struct efi_variable *)buf;
 372         struct efivar_entry *entry;
 373         int err = 0;
 374
 375         if (!capable(CAP_SYS_ADMIN))
 376                 return -EACCES;
 377
 378         efivar_entry_iter_begin();
 379         entry = efivar_entry_find(del_var->VariableName, del_var->VendorGuid,
 380                                   &efivar_sysfs_list, true);
 381         if (!entry)
 382                 err = -EINVAL;
 383         else if (__efivar_entry_delete(entry))
 384                 err = -EIO;
 385
 386         efivar_entry_iter_end();
 387
 388         if (err)
 389                 return err;
 390
 391         efivar_unregister(entry);
 392
 393         /* It's dead Jim.... */
 394         return count;
 395 }
 396
 397 /**
 398  * efivar_create_sysfs_entry - create a new entry in sysfs
 399  * @new_var: efivar entry to create
 400  *
 401  * Returns 1 on failure, 0 on success
 402  */
 403 static int
 404 efivar_create_sysfs_entry(struct efivar_entry *new_var)
 405 {
 406         int i, short_name_size;
 407         char *short_name;
 408         unsigned long variable_name_size;
 409         efi_char16_t *variable_name;
 410
 411         variable_name = new_var->var.VariableName;
 412         variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
 413
 414         /*
 415          * Length of the variable bytes in ASCII, plus the '-' separator,
 416          * plus the GUID, plus trailing NUL
 417          */
 418         short_name_size = variable_name_size / sizeof(efi_char16_t)
 419                                 + 1 + EFI_VARIABLE_GUID_LEN + 1;
 420
 421         short_name = kzalloc(short_name_size, GFP_KERNEL);
 422
 423         if (!short_name)
 424                 return 1;
 425
 426         /* Convert Unicode to normal chars (assume top bits are 0),
 427            ala UTF-8 */
 428         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
 429                 short_name[i] = variable_name[i] & 0xFF;
 430         }
 431         /* This is ugly, but necessary to separate one vendor's
 432            private variables from another's.         */
 433
 434         *(short_name + strlen(short_name)) = '-';
 435         efi_guid_unparse(&new_var->var.VendorGuid,
 436                          short_name + strlen(short_name));
 437
 438         new_var->kobj.kset = efivars_kset;
 439
 440         i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
 441                                    NULL, "%s", short_name);
 442         kfree(short_name);
 443         if (i)
 444                 return 1;
 445
 446         kobject_uevent(&new_var->kobj, KOBJ_ADD);
 447         efivar_entry_add(new_var, &efivar_sysfs_list);
 448
 449         return 0;
 450 }
 451
 452 static int
 453 create_efivars_bin_attributes(void)
 454 {
 455         struct bin_attribute *attr;
 456         int error;
 457
 458         /* new_var */
 459         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 460         if (!attr)
 461                 return -ENOMEM;
 462
 463         attr->attr.name = "new_var";
 464         attr->attr.mode = 0200;
 465         attr->write = efivar_create;
 466         efivars_new_var = attr;
 467
 468         /* del_var */
 469         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 470         if (!attr) {
 471                 error = -ENOMEM;
 472                 goto out_free;
 473         }
 474         attr->attr.name = "del_var";
 475         attr->attr.mode = 0200;
 476         attr->write = efivar_delete;
 477         efivars_del_var = attr;
 478
 479         sysfs_bin_attr_init(efivars_new_var);
 480         sysfs_bin_attr_init(efivars_del_var);
 481
 482         /* Register */
 483         error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
 484         if (error) {
 485                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
 486                         " due to error %d\n", error);
 487                 goto out_free;
 488         }
 489
 490         error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
 491         if (error) {
 492                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
 493                         " due to error %d\n", error);
 494                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
 495                 goto out_free;
 496         }
 497
 498         return 0;
 499 out_free:
 500         kfree(efivars_del_var);
 501         efivars_del_var = NULL;
 502         kfree(efivars_new_var);
 503         efivars_new_var = NULL;
 504         return error;
 505 }
 506
 507 static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
 508                                      unsigned long name_size, void *data)
 509 {
 510         struct efivar_entry *entry = data;
 511
 512         if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
 513                 return 0;
 514
 515         memcpy(entry->var.VariableName, name, name_size);
 516         memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
 517
 518         return 1;
 519 }
 520
 521 static void efivar_update_sysfs_entries(struct work_struct *work)
 522 {
 523         struct efivar_entry *entry;
 524         int err;
 525
 526         /* Add new sysfs entries */
 527         while (1) {
 528                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 529                 if (!entry)
 530                         return;
 531
 532                 err = efivar_init(efivar_update_sysfs_entry, entry,
 533                                   true, false, &efivar_sysfs_list);
 534                 if (!err)
 535                         break;
 536
 537                 efivar_create_sysfs_entry(entry);
 538         }
 539
 540         kfree(entry);
 541 }
 542
 543 static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
 544                                   unsigned long name_size, void *data)
 545 {
 546         struct efivar_entry *entry;
 547
 548         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 549         if (!entry)
 550                 return -ENOMEM;
 551
 552         memcpy(entry->var.VariableName, name, name_size);
 553         memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
 554
 555         efivar_create_sysfs_entry(entry);
 556
 557         return 0;
 558 }
 559
 560 static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
 561 {
 562         efivar_entry_remove(entry);
 563         efivar_unregister(entry);
 564         return 0;
 565 }
 566
 567 void efivars_sysfs_exit(void)
 568 {
 569         /* Remove all entries and destroy */
 570         __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
 571
 572         if (efivars_new_var)
 573                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
 574         if (efivars_del_var)
 575                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
 576         kfree(efivars_new_var);
 577         kfree(efivars_del_var);
 578         kset_unregister(efivars_kset);
 579 }
 580
 581 int efivars_sysfs_init(void)
 582 {
 583         struct kobject *parent_kobj = efivars_kobject();
 584         int error = 0;
 585
 586         /* No efivars has been registered yet */
 587         if (!parent_kobj)
 588                 return 0;
 589
 590         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 591                EFIVARS_DATE);
 592
 593         efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
 594         if (!efivars_kset) {
 595                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 596                 return -ENOMEM;
 597         }
 598
 599         efivar_init(efivars_sysfs_callback, NULL, false,
 600                     true, &efivar_sysfs_list);
 601
 602         error = create_efivars_bin_attributes();
 603         if (error) {
 604                 efivars_sysfs_exit();
 605                 return error;
 606         }
 607
 608         INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
 609
 610         return 0;
 611 }
 612 EXPORT_SYMBOL_GPL(efivars_sysfs_init);
 613
 614 module_init(efivars_sysfs_init);
 615 module_exit(efivars_sysfs_exit);