drivers/firmware/efivars.c

   1 /*
   2  * EFI Variables - efivars.c
   3  *
   4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
   5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
   6  *
   7  * This code takes all variables accessible from EFI runtime and
   8  *  exports them via sysfs
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  * Changelog:
  25  *
  26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
  27  *   remove check for efi_enabled in exit
  28  *   add MODULE_VERSION
  29  *
  30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
  31  *   minor bug fixes
  32  *
  33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
  34  *   converted driver to export variable information via sysfs
  35  *   and moved to drivers/firmware directory
  36  *   bumped revision number to v0.07 to reflect conversion & move
  37  *
  38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
  39  *   fix locking per Peter Chubb's findings
  40  *
  41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
  42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
  43  *
  44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
  45  *   use list_for_each_safe when deleting vars.
  46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
  47  *   v0.04 release to linux-ia64@linuxia64.org
  48  *
  49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
  50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
  51  *   efi.c own the /proc/efi directory.
  52  *   v0.03 release to linux-ia64@linuxia64.org
  53  *
  54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  55  *   At the request of Stephane, moved ownership of /proc/efi
  56  *   to efi.c, and now efivars lives under /proc/efi/vars.
  57  *
  58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  59  *   Feedback received from Stephane Eranian incorporated.
  60  *   efivar_write() checks copy_from_user() return value.
  61  *   efivar_read/write() returns proper errno.
  62  *   v0.02 release to linux-ia64@linuxia64.org
  63  *
  64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
  65  *   v0.01 release to linux-ia64@linuxia64.org
  66  */
  67
  68 #include <linux/capability.h>
  69 #include <linux/types.h>
  70 #include <linux/errno.h>
  71 #include <linux/init.h>
  72 #include <linux/mm.h>
  73 #include <linux/module.h>
  74 #include <linux/string.h>
  75 #include <linux/smp.h>
  76 #include <linux/efi.h>
  77 #include <linux/sysfs.h>
  78 #include <linux/kobject.h>
  79 #include <linux/device.h>
  80 #include <linux/slab.h>
  81 #include <linux/pstore.h>
  82
  83 #include <asm/uaccess.h>
  84
  85 #define EFIVARS_VERSION "0.08"
  86 #define EFIVARS_DATE "2004-May-17"
  87
  88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  90 MODULE_LICENSE("GPL");
  91 MODULE_VERSION(EFIVARS_VERSION);
  92
  93 #define DUMP_NAME_LEN 52
  94
  95 /*
  96  * The maximum size of VariableName + Data = 1024
  97  * Therefore, it's reasonable to save that much
  98  * space in each part of the structure,
  99  * and we use a page for reading/writing.
 100  */
 101
 102 struct efi_variable {
 103         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 104         efi_guid_t    VendorGuid;
 105         unsigned long DataSize;
 106         __u8          Data[1024];
 107         efi_status_t  Status;
 108         __u32         Attributes;
 109 } __attribute__((packed));
 110
 111
 112 struct efivar_entry {
 113         struct efivars *efivars;
 114         struct efi_variable var;
 115         struct list_head list;
 116         struct kobject kobj;
 117 };
 118
 119 struct efivar_attribute {
 120         struct attribute attr;
 121         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 122         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 123 };
 124
 125
 126 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 127 struct efivar_attribute efivar_attr_##_name = { \
 128         .attr = {.name = __stringify(_name), .mode = _mode}, \
 129         .show = _show, \
 130         .store = _store, \
 131 };
 132
 133 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 134 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 135
 136 /*
 137  * Prototype for sysfs creation function
 138  */
 139 static int
 140 efivar_create_sysfs_entry(struct efivars *efivars,
 141                           unsigned long variable_name_size,
 142                           efi_char16_t *variable_name,
 143                           efi_guid_t *vendor_guid);
 144
 145 /* Return the number of unicode characters in data */
 146 static unsigned long
 147 utf8_strlen(efi_char16_t *data, unsigned long maxlength)
 148 {
 149         unsigned long length = 0;
 150
 151         while (*data++ != 0 && length < maxlength)
 152                 length++;
 153         return length;
 154 }
 155
 156 /*
 157  * Return the number of bytes is the length of this string
 158  * Note: this is NOT the same as the number of unicode characters
 159  */
 160 static inline unsigned long
 161 utf8_strsize(efi_char16_t *data, unsigned long maxlength)
 162 {
 163         return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 164 }
 165
 166 static efi_status_t
 167 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 168 {
 169         efi_status_t status;
 170
 171         var->DataSize = 1024;
 172         status = efivars->ops->get_variable(var->VariableName,
 173                                             &var->VendorGuid,
 174                                             &var->Attributes,
 175                                             &var->DataSize,
 176                                             var->Data);
 177         return status;
 178 }
 179
 180 static efi_status_t
 181 get_var_data(struct efivars *efivars, struct efi_variable *var)
 182 {
 183         efi_status_t status;
 184
 185         spin_lock(&efivars->lock);
 186         status = get_var_data_locked(efivars, var);
 187         spin_unlock(&efivars->lock);
 188
 189         if (status != EFI_SUCCESS) {
 190                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 191                         status);
 192         }
 193         return status;
 194 }
 195
 196 static ssize_t
 197 efivar_guid_read(struct efivar_entry *entry, char *buf)
 198 {
 199         struct efi_variable *var = &entry->var;
 200         char *str = buf;
 201
 202         if (!entry || !buf)
 203                 return 0;
 204
 205         efi_guid_unparse(&var->VendorGuid, str);
 206         str += strlen(str);
 207         str += sprintf(str, "\n");
 208
 209         return str - buf;
 210 }
 211
 212 static ssize_t
 213 efivar_attr_read(struct efivar_entry *entry, char *buf)
 214 {
 215         struct efi_variable *var = &entry->var;
 216         char *str = buf;
 217         efi_status_t status;
 218
 219         if (!entry || !buf)
 220                 return -EINVAL;
 221
 222         status = get_var_data(entry->efivars, var);
 223         if (status != EFI_SUCCESS)
 224                 return -EIO;
 225
 226         if (var->Attributes & 0x1)
 227                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 228         if (var->Attributes & 0x2)
 229                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 230         if (var->Attributes & 0x4)
 231                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 232         return str - buf;
 233 }
 234
 235 static ssize_t
 236 efivar_size_read(struct efivar_entry *entry, char *buf)
 237 {
 238         struct efi_variable *var = &entry->var;
 239         char *str = buf;
 240         efi_status_t status;
 241
 242         if (!entry || !buf)
 243                 return -EINVAL;
 244
 245         status = get_var_data(entry->efivars, var);
 246         if (status != EFI_SUCCESS)
 247                 return -EIO;
 248
 249         str += sprintf(str, "0x%lx\n", var->DataSize);
 250         return str - buf;
 251 }
 252
 253 static ssize_t
 254 efivar_data_read(struct efivar_entry *entry, char *buf)
 255 {
 256         struct efi_variable *var = &entry->var;
 257         efi_status_t status;
 258
 259         if (!entry || !buf)
 260                 return -EINVAL;
 261
 262         status = get_var_data(entry->efivars, var);
 263         if (status != EFI_SUCCESS)
 264                 return -EIO;
 265
 266         memcpy(buf, var->Data, var->DataSize);
 267         return var->DataSize;
 268 }
 269 /*
 270  * We allow each variable to be edited via rewriting the
 271  * entire efi variable structure.
 272  */
 273 static ssize_t
 274 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 275 {
 276         struct efi_variable *new_var, *var = &entry->var;
 277         struct efivars *efivars = entry->efivars;
 278         efi_status_t status = EFI_NOT_FOUND;
 279
 280         if (count != sizeof(struct efi_variable))
 281                 return -EINVAL;
 282
 283         new_var = (struct efi_variable *)buf;
 284         /*
 285          * If only updating the variable data, then the name
 286          * and guid should remain the same
 287          */
 288         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 289                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 290                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 291                 return -EINVAL;
 292         }
 293
 294         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 295                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 296                 return -EINVAL;
 297         }
 298
 299         spin_lock(&efivars->lock);
 300         status = efivars->ops->set_variable(new_var->VariableName,
 301                                             &new_var->VendorGuid,
 302                                             new_var->Attributes,
 303                                             new_var->DataSize,
 304                                             new_var->Data);
 305
 306         spin_unlock(&efivars->lock);
 307
 308         if (status != EFI_SUCCESS) {
 309                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 310                         status);
 311                 return -EIO;
 312         }
 313
 314         memcpy(&entry->var, new_var, count);
 315         return count;
 316 }
 317
 318 static ssize_t
 319 efivar_show_raw(struct efivar_entry *entry, char *buf)
 320 {
 321         struct efi_variable *var = &entry->var;
 322         efi_status_t status;
 323
 324         if (!entry || !buf)
 325                 return 0;
 326
 327         status = get_var_data(entry->efivars, var);
 328         if (status != EFI_SUCCESS)
 329                 return -EIO;
 330
 331         memcpy(buf, var, sizeof(*var));
 332         return sizeof(*var);
 333 }
 334
 335 /*
 336  * Generic read/write functions that call the specific functions of
 337  * the attributes...
 338  */
 339 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 340                                 char *buf)
 341 {
 342         struct efivar_entry *var = to_efivar_entry(kobj);
 343         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 344         ssize_t ret = -EIO;
 345
 346         if (!capable(CAP_SYS_ADMIN))
 347                 return -EACCES;
 348
 349         if (efivar_attr->show) {
 350                 ret = efivar_attr->show(var, buf);
 351         }
 352         return ret;
 353 }
 354
 355 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 356                                 const char *buf, size_t count)
 357 {
 358         struct efivar_entry *var = to_efivar_entry(kobj);
 359         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 360         ssize_t ret = -EIO;
 361
 362         if (!capable(CAP_SYS_ADMIN))
 363                 return -EACCES;
 364
 365         if (efivar_attr->store)
 366                 ret = efivar_attr->store(var, buf, count);
 367
 368         return ret;
 369 }
 370
 371 static const struct sysfs_ops efivar_attr_ops = {
 372         .show = efivar_attr_show,
 373         .store = efivar_attr_store,
 374 };
 375
 376 static void efivar_release(struct kobject *kobj)
 377 {
 378         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 379         kfree(var);
 380 }
 381
 382 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 383 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 384 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 385 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 386 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 387
 388 static struct attribute *def_attrs[] = {
 389         &efivar_attr_guid.attr,
 390         &efivar_attr_size.attr,
 391         &efivar_attr_attributes.attr,
 392         &efivar_attr_data.attr,
 393         &efivar_attr_raw_var.attr,
 394         NULL,
 395 };
 396
 397 static struct kobj_type efivar_ktype = {
 398         .release = efivar_release,
 399         .sysfs_ops = &efivar_attr_ops,
 400         .default_attrs = def_attrs,
 401 };
 402
 403 static struct pstore_info efi_pstore_info;
 404
 405 static inline void
 406 efivar_unregister(struct efivar_entry *var)
 407 {
 408         kobject_put(&var->kobj);
 409 }
 410
 411 #ifdef CONFIG_PSTORE
 412
 413 static int efi_pstore_open(struct pstore_info *psi)
 414 {
 415         struct efivars *efivars = psi->data;
 416
 417         spin_lock(&efivars->lock);
 418         efivars->walk_entry = list_first_entry(&efivars->list,
 419                                                struct efivar_entry, list);
 420         return 0;
 421 }
 422
 423 static int efi_pstore_close(struct pstore_info *psi)
 424 {
 425         struct efivars *efivars = psi->data;
 426
 427         spin_unlock(&efivars->lock);
 428         return 0;
 429 }
 430
 431 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 432                                struct timespec *timespec, struct pstore_info *psi)
 433 {
 434         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 435         struct efivars *efivars = psi->data;
 436         char name[DUMP_NAME_LEN];
 437         int i;
 438         unsigned int part, size;
 439         unsigned long time;
 440
 441         while (&efivars->walk_entry->list != &efivars->list) {
 442                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 443                                  vendor)) {
 444                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 445                                 name[i] = efivars->walk_entry->var.VariableName[i];
 446                         }
 447                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 448                                 *id = part;
 449                                 timespec->tv_sec = time;
 450                                 timespec->tv_nsec = 0;
 451                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 452                                 size = efivars->walk_entry->var.DataSize;
 453                                 memcpy(psi->buf, efivars->walk_entry->var.Data, size);
 454                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 455                                                    struct efivar_entry, list);
 456                                 return size;
 457                         }
 458                 }
 459                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 460                                                  struct efivar_entry, list);
 461         }
 462         return 0;
 463 }
 464
 465 static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 466                             size_t size, struct pstore_info *psi)
 467 {
 468         char name[DUMP_NAME_LEN];
 469         char stub_name[DUMP_NAME_LEN];
 470         efi_char16_t efi_name[DUMP_NAME_LEN];
 471         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 472         struct efivars *efivars = psi->data;
 473         struct efivar_entry *entry, *found = NULL;
 474         int i;
 475
 476         sprintf(stub_name, "dump-type%u-%u-", type, part);
 477         sprintf(name, "%s%lu", stub_name, get_seconds());
 478
 479         spin_lock(&efivars->lock);
 480
 481         for (i = 0; i < DUMP_NAME_LEN; i++)
 482                 efi_name[i] = stub_name[i];
 483
 484         /*
 485          * Clean up any entries with the same name
 486          */
 487
 488         list_for_each_entry(entry, &efivars->list, list) {
 489                 get_var_data_locked(efivars, &entry->var);
 490
 491                 for (i = 0; i < DUMP_NAME_LEN; i++) {
 492                         if (efi_name[i] == 0) {
 493                                 found = entry;
 494                                 efivars->ops->set_variable(entry->var.VariableName,
 495                                                            &entry->var.VendorGuid,
 496                                                            EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 497                                                            0, NULL);
 498                                 break;
 499                         } else if (efi_name[i] != entry->var.VariableName[i]) {
 500                                 break;
 501                         }
 502                 }
 503         }
 504
 505         if (found)
 506                 list_del(&found->list);
 507
 508         for (i = 0; i < DUMP_NAME_LEN; i++)
 509                 efi_name[i] = name[i];
 510
 511         efivars->ops->set_variable(efi_name, &vendor,
 512                                    EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 513                                    size, psi->buf);
 514
 515         spin_unlock(&efivars->lock);
 516
 517         if (found)
 518                 efivar_unregister(found);
 519
 520         if (size)
 521                 efivar_create_sysfs_entry(efivars, utf8_strsize(efi_name, DUMP_NAME_LEN * 2),
 522                                           efi_name, &vendor);
 523
 524         return part;
 525 };
 526
 527 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 528                             struct pstore_info *psi)
 529 {
 530         efi_pstore_write(type, id, 0, psi);
 531
 532         return 0;
 533 }
 534 #else
 535 static int efi_pstore_open(struct pstore_info *psi)
 536 {
 537         return 0;
 538 }
 539
 540 static int efi_pstore_close(struct pstore_info *psi)
 541 {
 542         return 0;
 543 }
 544
 545 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 546                                struct timespec *time, struct pstore_info *psi)
 547 {
 548         return -1;
 549 }
 550
 551 static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size,
 552                             struct pstore_info *psi)
 553 {
 554         return 0;
 555 }
 556
 557 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 558                             struct pstore_info *psi)
 559 {
 560         return 0;
 561 }
 562 #endif
 563
 564 static struct pstore_info efi_pstore_info = {
 565         .owner          = THIS_MODULE,
 566         .name           = "efi",
 567         .open           = efi_pstore_open,
 568         .close          = efi_pstore_close,
 569         .read           = efi_pstore_read,
 570         .write          = efi_pstore_write,
 571         .erase          = efi_pstore_erase,
 572 };
 573
 574 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 575                              struct bin_attribute *bin_attr,
 576                              char *buf, loff_t pos, size_t count)
 577 {
 578         struct efi_variable *new_var = (struct efi_variable *)buf;
 579         struct efivars *efivars = bin_attr->private;
 580         struct efivar_entry *search_efivar, *n;
 581         unsigned long strsize1, strsize2;
 582         efi_status_t status = EFI_NOT_FOUND;
 583         int found = 0;
 584
 585         if (!capable(CAP_SYS_ADMIN))
 586                 return -EACCES;
 587
 588         spin_lock(&efivars->lock);
 589
 590         /*
 591          * Does this variable already exist?
 592          */
 593         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 594                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
 595                 strsize2 = utf8_strsize(new_var->VariableName, 1024);
 596                 if (strsize1 == strsize2 &&
 597                         !memcmp(&(search_efivar->var.VariableName),
 598                                 new_var->VariableName, strsize1) &&
 599                         !efi_guidcmp(search_efivar->var.VendorGuid,
 600                                 new_var->VendorGuid)) {
 601                         found = 1;
 602                         break;
 603                 }
 604         }
 605         if (found) {
 606                 spin_unlock(&efivars->lock);
 607                 return -EINVAL;
 608         }
 609
 610         /* now *really* create the variable via EFI */
 611         status = efivars->ops->set_variable(new_var->VariableName,
 612                                             &new_var->VendorGuid,
 613                                             new_var->Attributes,
 614                                             new_var->DataSize,
 615                                             new_var->Data);
 616
 617         if (status != EFI_SUCCESS) {
 618                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 619                         status);
 620                 spin_unlock(&efivars->lock);
 621                 return -EIO;
 622         }
 623         spin_unlock(&efivars->lock);
 624
 625         /* Create the entry in sysfs.  Locking is not required here */
 626         status = efivar_create_sysfs_entry(efivars,
 627                                            utf8_strsize(new_var->VariableName,
 628                                                         1024),
 629                                            new_var->VariableName,
 630                                            &new_var->VendorGuid);
 631         if (status) {
 632                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 633         }
 634         return count;
 635 }
 636
 637 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 638                              struct bin_attribute *bin_attr,
 639                              char *buf, loff_t pos, size_t count)
 640 {
 641         struct efi_variable *del_var = (struct efi_variable *)buf;
 642         struct efivars *efivars = bin_attr->private;
 643         struct efivar_entry *search_efivar, *n;
 644         unsigned long strsize1, strsize2;
 645         efi_status_t status = EFI_NOT_FOUND;
 646         int found = 0;
 647
 648         if (!capable(CAP_SYS_ADMIN))
 649                 return -EACCES;
 650
 651         spin_lock(&efivars->lock);
 652
 653         /*
 654          * Does this variable already exist?
 655          */
 656         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 657                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
 658                 strsize2 = utf8_strsize(del_var->VariableName, 1024);
 659                 if (strsize1 == strsize2 &&
 660                         !memcmp(&(search_efivar->var.VariableName),
 661                                 del_var->VariableName, strsize1) &&
 662                         !efi_guidcmp(search_efivar->var.VendorGuid,
 663                                 del_var->VendorGuid)) {
 664                         found = 1;
 665                         break;
 666                 }
 667         }
 668         if (!found) {
 669                 spin_unlock(&efivars->lock);
 670                 return -EINVAL;
 671         }
 672         /* force the Attributes/DataSize to 0 to ensure deletion */
 673         del_var->Attributes = 0;
 674         del_var->DataSize = 0;
 675
 676         status = efivars->ops->set_variable(del_var->VariableName,
 677                                             &del_var->VendorGuid,
 678                                             del_var->Attributes,
 679                                             del_var->DataSize,
 680                                             del_var->Data);
 681
 682         if (status != EFI_SUCCESS) {
 683                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 684                         status);
 685                 spin_unlock(&efivars->lock);
 686                 return -EIO;
 687         }
 688         list_del(&search_efivar->list);
 689         /* We need to release this lock before unregistering. */
 690         spin_unlock(&efivars->lock);
 691         efivar_unregister(search_efivar);
 692
 693         /* It's dead Jim.... */
 694         return count;
 695 }
 696
 697 /*
 698  * Let's not leave out systab information that snuck into
 699  * the efivars driver
 700  */
 701 static ssize_t systab_show(struct kobject *kobj,
 702                            struct kobj_attribute *attr, char *buf)
 703 {
 704         char *str = buf;
 705
 706         if (!kobj || !buf)
 707                 return -EINVAL;
 708
 709         if (efi.mps != EFI_INVALID_TABLE_ADDR)
 710                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 711         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 712                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 713         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 714                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 715         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 716                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 717         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 718                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 719         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 720                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 721         if (efi.uga != EFI_INVALID_TABLE_ADDR)
 722                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 723
 724         return str - buf;
 725 }
 726
 727 static struct kobj_attribute efi_attr_systab =
 728                         __ATTR(systab, 0400, systab_show, NULL);
 729
 730 static struct attribute *efi_subsys_attrs[] = {
 731         &efi_attr_systab.attr,
 732         NULL,   /* maybe more in the future? */
 733 };
 734
 735 static struct attribute_group efi_subsys_attr_group = {
 736         .attrs = efi_subsys_attrs,
 737 };
 738
 739 static struct kobject *efi_kobj;
 740
 741 /*
 742  * efivar_create_sysfs_entry()
 743  * Requires:
 744  *    variable_name_size = number of bytes required to hold
 745  *                         variable_name (not counting the NULL
 746  *                         character at the end.
 747  *    efivars->lock is not held on entry or exit.
 748  * Returns 1 on failure, 0 on success
 749  */
 750 static int
 751 efivar_create_sysfs_entry(struct efivars *efivars,
 752                           unsigned long variable_name_size,
 753                           efi_char16_t *variable_name,
 754                           efi_guid_t *vendor_guid)
 755 {
 756         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 757         char *short_name;
 758         struct efivar_entry *new_efivar;
 759
 760         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 761         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 762
 763         if (!short_name || !new_efivar)  {
 764                 kfree(short_name);
 765                 kfree(new_efivar);
 766                 return 1;
 767         }
 768
 769         new_efivar->efivars = efivars;
 770         memcpy(new_efivar->var.VariableName, variable_name,
 771                 variable_name_size);
 772         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
 773
 774         /* Convert Unicode to normal chars (assume top bits are 0),
 775            ala UTF-8 */
 776         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
 777                 short_name[i] = variable_name[i] & 0xFF;
 778         }
 779         /* This is ugly, but necessary to separate one vendor's
 780            private variables from another's.         */
 781
 782         *(short_name + strlen(short_name)) = '-';
 783         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
 784
 785         new_efivar->kobj.kset = efivars->kset;
 786         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
 787                                  "%s", short_name);
 788         if (i) {
 789                 kfree(short_name);
 790                 kfree(new_efivar);
 791                 return 1;
 792         }
 793
 794         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
 795         kfree(short_name);
 796         short_name = NULL;
 797
 798         spin_lock(&efivars->lock);
 799         list_add(&new_efivar->list, &efivars->list);
 800         spin_unlock(&efivars->lock);
 801
 802         return 0;
 803 }
 804
 805 static int
 806 create_efivars_bin_attributes(struct efivars *efivars)
 807 {
 808         struct bin_attribute *attr;
 809         int error;
 810
 811         /* new_var */
 812         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 813         if (!attr)
 814                 return -ENOMEM;
 815
 816         attr->attr.name = "new_var";
 817         attr->attr.mode = 0200;
 818         attr->write = efivar_create;
 819         attr->private = efivars;
 820         efivars->new_var = attr;
 821
 822         /* del_var */
 823         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 824         if (!attr) {
 825                 error = -ENOMEM;
 826                 goto out_free;
 827         }
 828         attr->attr.name = "del_var";
 829         attr->attr.mode = 0200;
 830         attr->write = efivar_delete;
 831         attr->private = efivars;
 832         efivars->del_var = attr;
 833
 834         sysfs_bin_attr_init(efivars->new_var);
 835         sysfs_bin_attr_init(efivars->del_var);
 836
 837         /* Register */
 838         error = sysfs_create_bin_file(&efivars->kset->kobj,
 839                                       efivars->new_var);
 840         if (error) {
 841                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
 842                         " due to error %d\n", error);
 843                 goto out_free;
 844         }
 845         error = sysfs_create_bin_file(&efivars->kset->kobj,
 846                                       efivars->del_var);
 847         if (error) {
 848                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
 849                         " due to error %d\n", error);
 850                 sysfs_remove_bin_file(&efivars->kset->kobj,
 851                                       efivars->new_var);
 852                 goto out_free;
 853         }
 854
 855         return 0;
 856 out_free:
 857         kfree(efivars->del_var);
 858         efivars->del_var = NULL;
 859         kfree(efivars->new_var);
 860         efivars->new_var = NULL;
 861         return error;
 862 }
 863
 864 void unregister_efivars(struct efivars *efivars)
 865 {
 866         struct efivar_entry *entry, *n;
 867
 868         list_for_each_entry_safe(entry, n, &efivars->list, list) {
 869                 spin_lock(&efivars->lock);
 870                 list_del(&entry->list);
 871                 spin_unlock(&efivars->lock);
 872                 efivar_unregister(entry);
 873         }
 874         if (efivars->new_var)
 875                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
 876         if (efivars->del_var)
 877                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
 878         kfree(efivars->new_var);
 879         kfree(efivars->del_var);
 880         kset_unregister(efivars->kset);
 881 }
 882 EXPORT_SYMBOL_GPL(unregister_efivars);
 883
 884 int register_efivars(struct efivars *efivars,
 885                      const struct efivar_operations *ops,
 886                      struct kobject *parent_kobj)
 887 {
 888         efi_status_t status = EFI_NOT_FOUND;
 889         efi_guid_t vendor_guid;
 890         efi_char16_t *variable_name;
 891         unsigned long variable_name_size = 1024;
 892         int error = 0;
 893
 894         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
 895         if (!variable_name) {
 896                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
 897                 return -ENOMEM;
 898         }
 899
 900         spin_lock_init(&efivars->lock);
 901         INIT_LIST_HEAD(&efivars->list);
 902         efivars->ops = ops;
 903
 904         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
 905         if (!efivars->kset) {
 906                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 907                 error = -ENOMEM;
 908                 goto out;
 909         }
 910
 911         /*
 912          * Per EFI spec, the maximum storage allocated for both
 913          * the variable name and variable data is 1024 bytes.
 914          */
 915
 916         do {
 917                 variable_name_size = 1024;
 918
 919                 status = ops->get_next_variable(&variable_name_size,
 920                                                 variable_name,
 921                                                 &vendor_guid);
 922                 switch (status) {
 923                 case EFI_SUCCESS:
 924                         efivar_create_sysfs_entry(efivars,
 925                                                   variable_name_size,
 926                                                   variable_name,
 927                                                   &vendor_guid);
 928                         break;
 929                 case EFI_NOT_FOUND:
 930                         break;
 931                 default:
 932                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
 933                                 status);
 934                         status = EFI_NOT_FOUND;
 935                         break;
 936                 }
 937         } while (status != EFI_NOT_FOUND);
 938
 939         error = create_efivars_bin_attributes(efivars);
 940         if (error)
 941                 unregister_efivars(efivars);
 942
 943         efivars->efi_pstore_info = efi_pstore_info;
 944
 945         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
 946         if (efivars->efi_pstore_info.buf) {
 947                 efivars->efi_pstore_info.bufsize = 1024;
 948                 efivars->efi_pstore_info.data = efivars;
 949                 mutex_init(&efivars->efi_pstore_info.buf_mutex);
 950                 pstore_register(&efivars->efi_pstore_info);
 951         }
 952
 953 out:
 954         kfree(variable_name);
 955
 956         return error;
 957 }
 958 EXPORT_SYMBOL_GPL(register_efivars);
 959
 960 static struct efivars __efivars;
 961 static struct efivar_operations ops;
 962
 963 /*
 964  * For now we register the efi subsystem with the firmware subsystem
 965  * and the vars subsystem with the efi subsystem.  In the future, it
 966  * might make sense to split off the efi subsystem into its own
 967  * driver, but for now only efivars will register with it, so just
 968  * include it here.
 969  */
 970
 971 static int __init
 972 efivars_init(void)
 973 {
 974         int error = 0;
 975
 976         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 977                EFIVARS_DATE);
 978
 979         if (!efi_enabled)
 980                 return 0;
 981
 982         /* For now we'll register the efi directory at /sys/firmware/efi */
 983         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
 984         if (!efi_kobj) {
 985                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
 986                 return -ENOMEM;
 987         }
 988
 989         ops.get_variable = efi.get_variable;
 990         ops.set_variable = efi.set_variable;
 991         ops.get_next_variable = efi.get_next_variable;
 992         error = register_efivars(&__efivars, &ops, efi_kobj);
 993         if (error)
 994                 goto err_put;
 995
 996         /* Don't forget the systab entry */
 997         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
 998         if (error) {
 999                 printk(KERN_ERR
1000                        "efivars: Sysfs attribute export failed with error %d.\n",
1001                        error);
1002                 goto err_unregister;
1003         }
1004
1005         return 0;
1006
1007 err_unregister:
1008         unregister_efivars(&__efivars);
1009 err_put:
1010         kobject_put(efi_kobj);
1011         return error;
1012 }
1013
1014 static void __exit
1015 efivars_exit(void)
1016 {
1017         if (efi_enabled) {
1018                 unregister_efivars(&__efivars);
1019                 kobject_put(efi_kobj);
1020         }
1021 }
1022
1023 module_init(efivars_init);
1024 module_exit(efivars_exit);
1025