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
  71 #define EFIVARS_VERSION "0.08"
  72 #define EFIVARS_DATE "2004-May-17"
  73
  74 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  75 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  76 MODULE_LICENSE("GPL");
  77 MODULE_VERSION(EFIVARS_VERSION);
  78
  79 LIST_HEAD(efivar_sysfs_list);
  80 EXPORT_SYMBOL_GPL(efivar_sysfs_list);
  81
  82 static struct kset *efivars_kset;
  83
  84 static struct bin_attribute *efivars_new_var;
  85 static struct bin_attribute *efivars_del_var;
  86
  87 struct efivar_attribute {
  88         struct attribute attr;
  89         ssize_t (*show) (struct efivar_entry *entry, char *buf);
  90         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
  91 };
  92
  93 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
  94 struct efivar_attribute efivar_attr_##_name = { \
  95         .attr = {.name = __stringify(_name), .mode = _mode}, \
  96         .show = _show, \
  97         .store = _store, \
  98 };
  99
 100 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 101 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 102
 103 /*
 104  * Prototype for sysfs creation function
 105  */
 106 static int
 107 efivar_create_sysfs_entry(struct efivar_entry *new_var);
 108
 109 static ssize_t
 110 efivar_guid_read(struct efivar_entry *entry, char *buf)
 111 {
 112         struct efi_variable *var = &entry->var;
 113         char *str = buf;
 114
 115         if (!entry || !buf)
 116                 return 0;
 117
 118         efi_guid_unparse(&var->VendorGuid, str);
 119         str += strlen(str);
 120         str += sprintf(str, "\n");
 121
 122         return str - buf;
 123 }
 124
 125 static ssize_t
 126 efivar_attr_read(struct efivar_entry *entry, char *buf)
 127 {
 128         struct efi_variable *var = &entry->var;
 129         char *str = buf;
 130
 131         if (!entry || !buf)
 132                 return -EINVAL;
 133
 134         var->DataSize = 1024;
 135         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 136                 return -EIO;
 137
 138         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 139                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 140         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 141                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 142         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 143                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 144         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 145                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 146         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 147                 str += sprintf(str,
 148                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 149         if (var->Attributes &
 150                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 151                 str += sprintf(str,
 152                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 153         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 154                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 155         return str - buf;
 156 }
 157
 158 static ssize_t
 159 efivar_size_read(struct efivar_entry *entry, char *buf)
 160 {
 161         struct efi_variable *var = &entry->var;
 162         char *str = buf;
 163
 164         if (!entry || !buf)
 165                 return -EINVAL;
 166
 167         var->DataSize = 1024;
 168         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 169                 return -EIO;
 170
 171         str += sprintf(str, "0x%lx\n", var->DataSize);
 172         return str - buf;
 173 }
 174
 175 static ssize_t
 176 efivar_data_read(struct efivar_entry *entry, char *buf)
 177 {
 178         struct efi_variable *var = &entry->var;
 179
 180         if (!entry || !buf)
 181                 return -EINVAL;
 182
 183         var->DataSize = 1024;
 184         if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
 185                 return -EIO;
 186
 187         memcpy(buf, var->Data, var->DataSize);
 188         return var->DataSize;
 189 }
 190 /*
 191  * We allow each variable to be edited via rewriting the
 192  * entire efi variable structure.
 193  */
 194 static ssize_t
 195 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 196 {
 197         struct efi_variable *new_var, *var = &entry->var;
 198         int err;
 199
 200         if (count != sizeof(struct efi_variable))
 201                 return -EINVAL;
 202
 203         new_var = (struct efi_variable *)buf;
 204         /*
 205          * If only updating the variable data, then the name
 206          * and guid should remain the same
 207          */
 208         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 209                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 210                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 211                 return -EINVAL;
 212         }
 213
 214         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 215                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 216                 return -EINVAL;
 217         }
 218
 219         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 220             efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) {
 221                 printk(KERN_ERR "efivars: Malformed variable content\n");
 222                 return -EINVAL;
 223         }
 224
 225         memcpy(&entry->var, new_var, count);
 226
 227         err = efivar_entry_set(entry, new_var->Attributes,
 228                                new_var->DataSize, new_var->Data, false);
 229         if (err) {
 230                 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
 231                 return -EIO;
 232         }
 233
 234         return count;
 235 }
 236
 237 static ssize_t
 238 efivar_show_raw(struct efivar_entry *entry, char *buf)
 239 {
 240         struct efi_variable *var = &entry->var;
 241
 242         if (!entry || !buf)
 243                 return 0;
 244
 245         var->DataSize = 1024;
 246         if (efivar_entry_get(entry, &entry->var.Attributes,
 247                              &entry->var.DataSize, entry->var.Data))
 248                 return -EIO;
 249
 250         memcpy(buf, var, sizeof(*var));
 251
 252         return sizeof(*var);
 253 }
 254
 255 /*
 256  * Generic read/write functions that call the specific functions of
 257  * the attributes...
 258  */
 259 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 260                                 char *buf)
 261 {
 262         struct efivar_entry *var = to_efivar_entry(kobj);
 263         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 264         ssize_t ret = -EIO;
 265
 266         if (!capable(CAP_SYS_ADMIN))
 267                 return -EACCES;
 268
 269         if (efivar_attr->show) {
 270                 ret = efivar_attr->show(var, buf);
 271         }
 272         return ret;
 273 }
 274
 275 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 276                                 const char *buf, size_t count)
 277 {
 278         struct efivar_entry *var = to_efivar_entry(kobj);
 279         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 280         ssize_t ret = -EIO;
 281
 282         if (!capable(CAP_SYS_ADMIN))
 283                 return -EACCES;
 284
 285         if (efivar_attr->store)
 286                 ret = efivar_attr->store(var, buf, count);
 287
 288         return ret;
 289 }
 290
 291 static const struct sysfs_ops efivar_attr_ops = {
 292         .show = efivar_attr_show,
 293         .store = efivar_attr_store,
 294 };
 295
 296 static void efivar_release(struct kobject *kobj)
 297 {
 298         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 299         kfree(var);
 300 }
 301
 302 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 303 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 304 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 305 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 306 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 307
 308 static struct attribute *def_attrs[] = {
 309         &efivar_attr_guid.attr,
 310         &efivar_attr_size.attr,
 311         &efivar_attr_attributes.attr,
 312         &efivar_attr_data.attr,
 313         &efivar_attr_raw_var.attr,
 314         NULL,
 315 };
 316
 317 static struct kobj_type efivar_ktype = {
 318         .release = efivar_release,
 319         .sysfs_ops = &efivar_attr_ops,
 320         .default_attrs = def_attrs,
 321 };
 322
 323 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 324                              struct bin_attribute *bin_attr,
 325                              char *buf, loff_t pos, size_t count)
 326 {
 327         struct efi_variable *new_var = (struct efi_variable *)buf;
 328         struct efivar_entry *new_entry;
 329         int err;
 330
 331         if (!capable(CAP_SYS_ADMIN))
 332                 return -EACCES;
 333
 334         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 335             efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) {
 336                 printk(KERN_ERR "efivars: Malformed variable content\n");
 337                 return -EINVAL;
 338         }
 339
 340         new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
 341         if (!new_entry)
 342                 return -ENOMEM;
 343
 344         memcpy(&new_entry->var, new_var, sizeof(*new_var));
 345
 346         err = efivar_entry_set(new_entry, new_var->Attributes, new_var->DataSize,
 347                                new_var->Data, &efivar_sysfs_list);
 348         if (err) {
 349                 if (err == -EEXIST)
 350                         err = -EINVAL;
 351                 goto out;
 352         }
 353
 354         if (efivar_create_sysfs_entry(new_entry)) {
 355                 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
 356                 kfree(new_entry);
 357         }
 358         return count;
 359
 360 out:
 361         kfree(new_entry);
 362         return err;
 363 }
 364
 365 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 366                              struct bin_attribute *bin_attr,
 367                              char *buf, loff_t pos, size_t count)
 368 {
 369         struct efi_variable *del_var = (struct efi_variable *)buf;
 370         struct efivar_entry *entry;
 371         int err = 0;
 372
 373         if (!capable(CAP_SYS_ADMIN))
 374                 return -EACCES;
 375
 376         efivar_entry_iter_begin();
 377         entry = efivar_entry_find(del_var->VariableName, del_var->VendorGuid,
 378                                   &efivar_sysfs_list, true);
 379         if (!entry)
 380                 err = -EINVAL;
 381         else if (__efivar_entry_delete(entry))
 382                 err = -EIO;
 383
 384         efivar_entry_iter_end();
 385
 386         if (err)
 387                 return err;
 388
 389         efivar_unregister(entry);
 390
 391         /* It's dead Jim.... */
 392         return count;
 393 }
 394
 395 /**
 396  * efivar_create_sysfs_entry - create a new entry in sysfs
 397  * @new_var: efivar entry to create
 398  *
 399  * Returns 1 on failure, 0 on success
 400  */
 401 static int
 402 efivar_create_sysfs_entry(struct efivar_entry *new_var)
 403 {
 404         int i, short_name_size;
 405         char *short_name;
 406         unsigned long variable_name_size;
 407         efi_char16_t *variable_name;
 408
 409         variable_name = new_var->var.VariableName;
 410         variable_name_size = utf16_strlen(variable_name) * sizeof(efi_char16_t);
 411
 412         /*
 413          * Length of the variable bytes in ASCII, plus the '-' separator,
 414          * plus the GUID, plus trailing NUL
 415          */
 416         short_name_size = variable_name_size / sizeof(efi_char16_t)
 417                                 + 1 + EFI_VARIABLE_GUID_LEN + 1;
 418
 419         short_name = kzalloc(short_name_size, GFP_KERNEL);
 420
 421         if (!short_name) {
 422                 kfree(short_name);
 423                 return 1;
 424         }
 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         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 527         if (!entry)
 528                 return;
 529
 530         /* Add new sysfs entries */
 531         while (1) {
 532                 memset(entry, 0, sizeof(*entry));
 533
 534                 err = efivar_init(efivar_update_sysfs_entry, entry,
 535                                   true, false, &efivar_sysfs_list);
 536                 if (!err)
 537                         break;
 538
 539                 efivar_create_sysfs_entry(entry);
 540         }
 541
 542         kfree(entry);
 543 }
 544
 545 static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
 546                                   unsigned long name_size, void *data)
 547 {
 548         struct efivar_entry *entry;
 549
 550         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 551         if (!entry)
 552                 return -ENOMEM;
 553
 554         memcpy(entry->var.VariableName, name, name_size);
 555         memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
 556
 557         efivar_create_sysfs_entry(entry);
 558
 559         return 0;
 560 }
 561
 562 static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
 563 {
 564         efivar_entry_remove(entry);
 565         efivar_unregister(entry);
 566         return 0;
 567 }
 568
 569 void efivars_sysfs_exit(void)
 570 {
 571         /* Remove all entries and destroy */
 572         __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
 573
 574         if (efivars_new_var)
 575                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
 576         if (efivars_del_var)
 577                 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
 578         kfree(efivars_new_var);
 579         kfree(efivars_del_var);
 580         kset_unregister(efivars_kset);
 581 }
 582
 583 int efivars_sysfs_init(void)
 584 {
 585         struct kobject *parent_kobj = efivars_kobject();
 586         int error = 0;
 587
 588         /* No efivars has been registered yet */
 589         if (!parent_kobj)
 590                 return 0;
 591
 592         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 593                EFIVARS_DATE);
 594
 595         efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
 596         if (!efivars_kset) {
 597                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 598                 return -ENOMEM;
 599         }
 600
 601         efivar_init(efivars_sysfs_callback, NULL, false,
 602                     true, &efivar_sysfs_list);
 603
 604         error = create_efivars_bin_attributes();
 605         if (error) {
 606                 efivars_sysfs_exit();
 607                 return error;
 608         }
 609
 610         INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
 611
 612         return 0;
 613 }
 614 EXPORT_SYMBOL_GPL(efivars_sysfs_init);
 615
 616 module_init(efivars_sysfs_init);
 617 module_exit(efivars_sysfs_exit);