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 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 148 {
 149         unsigned long length = 0;
 150
 151         while (*s++ != 0 && length < maxlength)
 152                 length++;
 153         return length;
 154 }
 155
 156 static unsigned long
 157 utf16_strlen(efi_char16_t *s)
 158 {
 159         return utf16_strnlen(s, ~0UL);
 160 }
 161
 162 /*
 163  * Return the number of bytes is the length of this string
 164  * Note: this is NOT the same as the number of unicode characters
 165  */
 166 static inline unsigned long
 167 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 168 {
 169         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 170 }
 171
 172 static inline int
 173 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 174 {
 175         while (1) {
 176                 if (len == 0)
 177                         return 0;
 178                 if (*a < *b)
 179                         return -1;
 180                 if (*a > *b)
 181                         return 1;
 182                 if (*a == 0) /* implies *b == 0 */
 183                         return 0;
 184                 a++;
 185                 b++;
 186                 len--;
 187         }
 188 }
 189
 190 static efi_status_t
 191 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 192 {
 193         efi_status_t status;
 194
 195         var->DataSize = 1024;
 196         status = efivars->ops->get_variable(var->VariableName,
 197                                             &var->VendorGuid,
 198                                             &var->Attributes,
 199                                             &var->DataSize,
 200                                             var->Data);
 201         return status;
 202 }
 203
 204 static efi_status_t
 205 get_var_data(struct efivars *efivars, struct efi_variable *var)
 206 {
 207         efi_status_t status;
 208
 209         spin_lock(&efivars->lock);
 210         status = get_var_data_locked(efivars, var);
 211         spin_unlock(&efivars->lock);
 212
 213         if (status != EFI_SUCCESS) {
 214                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 215                         status);
 216         }
 217         return status;
 218 }
 219
 220 static ssize_t
 221 efivar_guid_read(struct efivar_entry *entry, char *buf)
 222 {
 223         struct efi_variable *var = &entry->var;
 224         char *str = buf;
 225
 226         if (!entry || !buf)
 227                 return 0;
 228
 229         efi_guid_unparse(&var->VendorGuid, str);
 230         str += strlen(str);
 231         str += sprintf(str, "\n");
 232
 233         return str - buf;
 234 }
 235
 236 static ssize_t
 237 efivar_attr_read(struct efivar_entry *entry, char *buf)
 238 {
 239         struct efi_variable *var = &entry->var;
 240         char *str = buf;
 241         efi_status_t status;
 242
 243         if (!entry || !buf)
 244                 return -EINVAL;
 245
 246         status = get_var_data(entry->efivars, var);
 247         if (status != EFI_SUCCESS)
 248                 return -EIO;
 249
 250         if (var->Attributes & 0x1)
 251                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 252         if (var->Attributes & 0x2)
 253                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 254         if (var->Attributes & 0x4)
 255                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 256         return str - buf;
 257 }
 258
 259 static ssize_t
 260 efivar_size_read(struct efivar_entry *entry, char *buf)
 261 {
 262         struct efi_variable *var = &entry->var;
 263         char *str = buf;
 264         efi_status_t status;
 265
 266         if (!entry || !buf)
 267                 return -EINVAL;
 268
 269         status = get_var_data(entry->efivars, var);
 270         if (status != EFI_SUCCESS)
 271                 return -EIO;
 272
 273         str += sprintf(str, "0x%lx\n", var->DataSize);
 274         return str - buf;
 275 }
 276
 277 static ssize_t
 278 efivar_data_read(struct efivar_entry *entry, char *buf)
 279 {
 280         struct efi_variable *var = &entry->var;
 281         efi_status_t status;
 282
 283         if (!entry || !buf)
 284                 return -EINVAL;
 285
 286         status = get_var_data(entry->efivars, var);
 287         if (status != EFI_SUCCESS)
 288                 return -EIO;
 289
 290         memcpy(buf, var->Data, var->DataSize);
 291         return var->DataSize;
 292 }
 293 /*
 294  * We allow each variable to be edited via rewriting the
 295  * entire efi variable structure.
 296  */
 297 static ssize_t
 298 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 299 {
 300         struct efi_variable *new_var, *var = &entry->var;
 301         struct efivars *efivars = entry->efivars;
 302         efi_status_t status = EFI_NOT_FOUND;
 303
 304         if (count != sizeof(struct efi_variable))
 305                 return -EINVAL;
 306
 307         new_var = (struct efi_variable *)buf;
 308         /*
 309          * If only updating the variable data, then the name
 310          * and guid should remain the same
 311          */
 312         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 313                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 314                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 315                 return -EINVAL;
 316         }
 317
 318         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 319                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 320                 return -EINVAL;
 321         }
 322
 323         spin_lock(&efivars->lock);
 324         status = efivars->ops->set_variable(new_var->VariableName,
 325                                             &new_var->VendorGuid,
 326                                             new_var->Attributes,
 327                                             new_var->DataSize,
 328                                             new_var->Data);
 329
 330         spin_unlock(&efivars->lock);
 331
 332         if (status != EFI_SUCCESS) {
 333                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 334                         status);
 335                 return -EIO;
 336         }
 337
 338         memcpy(&entry->var, new_var, count);
 339         return count;
 340 }
 341
 342 static ssize_t
 343 efivar_show_raw(struct efivar_entry *entry, char *buf)
 344 {
 345         struct efi_variable *var = &entry->var;
 346         efi_status_t status;
 347
 348         if (!entry || !buf)
 349                 return 0;
 350
 351         status = get_var_data(entry->efivars, var);
 352         if (status != EFI_SUCCESS)
 353                 return -EIO;
 354
 355         memcpy(buf, var, sizeof(*var));
 356         return sizeof(*var);
 357 }
 358
 359 /*
 360  * Generic read/write functions that call the specific functions of
 361  * the attributes...
 362  */
 363 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 364                                 char *buf)
 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->show) {
 374                 ret = efivar_attr->show(var, buf);
 375         }
 376         return ret;
 377 }
 378
 379 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 380                                 const char *buf, size_t count)
 381 {
 382         struct efivar_entry *var = to_efivar_entry(kobj);
 383         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 384         ssize_t ret = -EIO;
 385
 386         if (!capable(CAP_SYS_ADMIN))
 387                 return -EACCES;
 388
 389         if (efivar_attr->store)
 390                 ret = efivar_attr->store(var, buf, count);
 391
 392         return ret;
 393 }
 394
 395 static const struct sysfs_ops efivar_attr_ops = {
 396         .show = efivar_attr_show,
 397         .store = efivar_attr_store,
 398 };
 399
 400 static void efivar_release(struct kobject *kobj)
 401 {
 402         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 403         kfree(var);
 404 }
 405
 406 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 407 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 408 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 409 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 410 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 411
 412 static struct attribute *def_attrs[] = {
 413         &efivar_attr_guid.attr,
 414         &efivar_attr_size.attr,
 415         &efivar_attr_attributes.attr,
 416         &efivar_attr_data.attr,
 417         &efivar_attr_raw_var.attr,
 418         NULL,
 419 };
 420
 421 static struct kobj_type efivar_ktype = {
 422         .release = efivar_release,
 423         .sysfs_ops = &efivar_attr_ops,
 424         .default_attrs = def_attrs,
 425 };
 426
 427 static struct pstore_info efi_pstore_info;
 428
 429 static inline void
 430 efivar_unregister(struct efivar_entry *var)
 431 {
 432         kobject_put(&var->kobj);
 433 }
 434
 435 #ifdef CONFIG_PSTORE
 436
 437 static int efi_pstore_open(struct pstore_info *psi)
 438 {
 439         struct efivars *efivars = psi->data;
 440
 441         spin_lock(&efivars->lock);
 442         efivars->walk_entry = list_first_entry(&efivars->list,
 443                                                struct efivar_entry, list);
 444         return 0;
 445 }
 446
 447 static int efi_pstore_close(struct pstore_info *psi)
 448 {
 449         struct efivars *efivars = psi->data;
 450
 451         spin_unlock(&efivars->lock);
 452         return 0;
 453 }
 454
 455 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 456                                struct timespec *timespec, struct pstore_info *psi)
 457 {
 458         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 459         struct efivars *efivars = psi->data;
 460         char name[DUMP_NAME_LEN];
 461         int i;
 462         unsigned int part, size;
 463         unsigned long time;
 464
 465         while (&efivars->walk_entry->list != &efivars->list) {
 466                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 467                                  vendor)) {
 468                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 469                                 name[i] = efivars->walk_entry->var.VariableName[i];
 470                         }
 471                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 472                                 *id = part;
 473                                 timespec->tv_sec = time;
 474                                 timespec->tv_nsec = 0;
 475                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 476                                 size = efivars->walk_entry->var.DataSize;
 477                                 memcpy(psi->buf, efivars->walk_entry->var.Data, size);
 478                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 479                                                    struct efivar_entry, list);
 480                                 return size;
 481                         }
 482                 }
 483                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 484                                                  struct efivar_entry, list);
 485         }
 486         return 0;
 487 }
 488
 489 static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 490                             size_t size, struct pstore_info *psi)
 491 {
 492         char name[DUMP_NAME_LEN];
 493         char stub_name[DUMP_NAME_LEN];
 494         efi_char16_t efi_name[DUMP_NAME_LEN];
 495         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 496         struct efivars *efivars = psi->data;
 497         struct efivar_entry *entry, *found = NULL;
 498         int i;
 499
 500         sprintf(stub_name, "dump-type%u-%u-", type, part);
 501         sprintf(name, "%s%lu", stub_name, get_seconds());
 502
 503         spin_lock(&efivars->lock);
 504
 505         for (i = 0; i < DUMP_NAME_LEN; i++)
 506                 efi_name[i] = stub_name[i];
 507
 508         /*
 509          * Clean up any entries with the same name
 510          */
 511
 512         list_for_each_entry(entry, &efivars->list, list) {
 513                 get_var_data_locked(efivars, &entry->var);
 514
 515                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
 516                         continue;
 517                 if (utf16_strncmp(entry->var.VariableName, efi_name,
 518                                   utf16_strlen(efi_name)))
 519                         continue;
 520                 /* Needs to be a prefix */
 521                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 522                         continue;
 523
 524                 /* found */
 525                 found = entry;
 526                 efivars->ops->set_variable(entry->var.VariableName, &entry->var.VendorGuid,
 527                                            EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 528                                            0, NULL);
 529         }
 530
 531         if (found)
 532                 list_del(&found->list);
 533
 534         for (i = 0; i < DUMP_NAME_LEN; i++)
 535                 efi_name[i] = name[i];
 536
 537         efivars->ops->set_variable(efi_name, &vendor,
 538                                    EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 539                                    size, psi->buf);
 540
 541         spin_unlock(&efivars->lock);
 542
 543         if (found)
 544                 efivar_unregister(found);
 545
 546         if (size)
 547                 efivar_create_sysfs_entry(efivars,
 548                                           utf16_strsize(efi_name,
 549                                                         DUMP_NAME_LEN * 2),
 550                                           efi_name, &vendor);
 551
 552         return part;
 553 };
 554
 555 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 556                             struct pstore_info *psi)
 557 {
 558         efi_pstore_write(type, id, 0, psi);
 559
 560         return 0;
 561 }
 562 #else
 563 static int efi_pstore_open(struct pstore_info *psi)
 564 {
 565         return 0;
 566 }
 567
 568 static int efi_pstore_close(struct pstore_info *psi)
 569 {
 570         return 0;
 571 }
 572
 573 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 574                                struct timespec *time, struct pstore_info *psi)
 575 {
 576         return -1;
 577 }
 578
 579 static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size,
 580                             struct pstore_info *psi)
 581 {
 582         return 0;
 583 }
 584
 585 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 586                             struct pstore_info *psi)
 587 {
 588         return 0;
 589 }
 590 #endif
 591
 592 static struct pstore_info efi_pstore_info = {
 593         .owner          = THIS_MODULE,
 594         .name           = "efi",
 595         .open           = efi_pstore_open,
 596         .close          = efi_pstore_close,
 597         .read           = efi_pstore_read,
 598         .write          = efi_pstore_write,
 599         .erase          = efi_pstore_erase,
 600 };
 601
 602 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 603                              struct bin_attribute *bin_attr,
 604                              char *buf, loff_t pos, size_t count)
 605 {
 606         struct efi_variable *new_var = (struct efi_variable *)buf;
 607         struct efivars *efivars = bin_attr->private;
 608         struct efivar_entry *search_efivar, *n;
 609         unsigned long strsize1, strsize2;
 610         efi_status_t status = EFI_NOT_FOUND;
 611         int found = 0;
 612
 613         if (!capable(CAP_SYS_ADMIN))
 614                 return -EACCES;
 615
 616         spin_lock(&efivars->lock);
 617
 618         /*
 619          * Does this variable already exist?
 620          */
 621         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 622                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 623                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
 624                 if (strsize1 == strsize2 &&
 625                         !memcmp(&(search_efivar->var.VariableName),
 626                                 new_var->VariableName, strsize1) &&
 627                         !efi_guidcmp(search_efivar->var.VendorGuid,
 628                                 new_var->VendorGuid)) {
 629                         found = 1;
 630                         break;
 631                 }
 632         }
 633         if (found) {
 634                 spin_unlock(&efivars->lock);
 635                 return -EINVAL;
 636         }
 637
 638         /* now *really* create the variable via EFI */
 639         status = efivars->ops->set_variable(new_var->VariableName,
 640                                             &new_var->VendorGuid,
 641                                             new_var->Attributes,
 642                                             new_var->DataSize,
 643                                             new_var->Data);
 644
 645         if (status != EFI_SUCCESS) {
 646                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 647                         status);
 648                 spin_unlock(&efivars->lock);
 649                 return -EIO;
 650         }
 651         spin_unlock(&efivars->lock);
 652
 653         /* Create the entry in sysfs.  Locking is not required here */
 654         status = efivar_create_sysfs_entry(efivars,
 655                                            utf16_strsize(new_var->VariableName,
 656                                                          1024),
 657                                            new_var->VariableName,
 658                                            &new_var->VendorGuid);
 659         if (status) {
 660                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 661         }
 662         return count;
 663 }
 664
 665 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 666                              struct bin_attribute *bin_attr,
 667                              char *buf, loff_t pos, size_t count)
 668 {
 669         struct efi_variable *del_var = (struct efi_variable *)buf;
 670         struct efivars *efivars = bin_attr->private;
 671         struct efivar_entry *search_efivar, *n;
 672         unsigned long strsize1, strsize2;
 673         efi_status_t status = EFI_NOT_FOUND;
 674         int found = 0;
 675
 676         if (!capable(CAP_SYS_ADMIN))
 677                 return -EACCES;
 678
 679         spin_lock(&efivars->lock);
 680
 681         /*
 682          * Does this variable already exist?
 683          */
 684         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 685                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 686                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
 687                 if (strsize1 == strsize2 &&
 688                         !memcmp(&(search_efivar->var.VariableName),
 689                                 del_var->VariableName, strsize1) &&
 690                         !efi_guidcmp(search_efivar->var.VendorGuid,
 691                                 del_var->VendorGuid)) {
 692                         found = 1;
 693                         break;
 694                 }
 695         }
 696         if (!found) {
 697                 spin_unlock(&efivars->lock);
 698                 return -EINVAL;
 699         }
 700         /* force the Attributes/DataSize to 0 to ensure deletion */
 701         del_var->Attributes = 0;
 702         del_var->DataSize = 0;
 703
 704         status = efivars->ops->set_variable(del_var->VariableName,
 705                                             &del_var->VendorGuid,
 706                                             del_var->Attributes,
 707                                             del_var->DataSize,
 708                                             del_var->Data);
 709
 710         if (status != EFI_SUCCESS) {
 711                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 712                         status);
 713                 spin_unlock(&efivars->lock);
 714                 return -EIO;
 715         }
 716         list_del(&search_efivar->list);
 717         /* We need to release this lock before unregistering. */
 718         spin_unlock(&efivars->lock);
 719         efivar_unregister(search_efivar);
 720
 721         /* It's dead Jim.... */
 722         return count;
 723 }
 724
 725 /*
 726  * Let's not leave out systab information that snuck into
 727  * the efivars driver
 728  */
 729 static ssize_t systab_show(struct kobject *kobj,
 730                            struct kobj_attribute *attr, char *buf)
 731 {
 732         char *str = buf;
 733
 734         if (!kobj || !buf)
 735                 return -EINVAL;
 736
 737         if (efi.mps != EFI_INVALID_TABLE_ADDR)
 738                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 739         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 740                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 741         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 742                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 743         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 744                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 745         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 746                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 747         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 748                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 749         if (efi.uga != EFI_INVALID_TABLE_ADDR)
 750                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 751
 752         return str - buf;
 753 }
 754
 755 static struct kobj_attribute efi_attr_systab =
 756                         __ATTR(systab, 0400, systab_show, NULL);
 757
 758 static struct attribute *efi_subsys_attrs[] = {
 759         &efi_attr_systab.attr,
 760         NULL,   /* maybe more in the future? */
 761 };
 762
 763 static struct attribute_group efi_subsys_attr_group = {
 764         .attrs = efi_subsys_attrs,
 765 };
 766
 767 static struct kobject *efi_kobj;
 768
 769 /*
 770  * efivar_create_sysfs_entry()
 771  * Requires:
 772  *    variable_name_size = number of bytes required to hold
 773  *                         variable_name (not counting the NULL
 774  *                         character at the end.
 775  *    efivars->lock is not held on entry or exit.
 776  * Returns 1 on failure, 0 on success
 777  */
 778 static int
 779 efivar_create_sysfs_entry(struct efivars *efivars,
 780                           unsigned long variable_name_size,
 781                           efi_char16_t *variable_name,
 782                           efi_guid_t *vendor_guid)
 783 {
 784         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 785         char *short_name;
 786         struct efivar_entry *new_efivar;
 787
 788         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 789         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 790
 791         if (!short_name || !new_efivar)  {
 792                 kfree(short_name);
 793                 kfree(new_efivar);
 794                 return 1;
 795         }
 796
 797         new_efivar->efivars = efivars;
 798         memcpy(new_efivar->var.VariableName, variable_name,
 799                 variable_name_size);
 800         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
 801
 802         /* Convert Unicode to normal chars (assume top bits are 0),
 803            ala UTF-8 */
 804         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
 805                 short_name[i] = variable_name[i] & 0xFF;
 806         }
 807         /* This is ugly, but necessary to separate one vendor's
 808            private variables from another's.         */
 809
 810         *(short_name + strlen(short_name)) = '-';
 811         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
 812
 813         new_efivar->kobj.kset = efivars->kset;
 814         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
 815                                  "%s", short_name);
 816         if (i) {
 817                 kfree(short_name);
 818                 kfree(new_efivar);
 819                 return 1;
 820         }
 821
 822         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
 823         kfree(short_name);
 824         short_name = NULL;
 825
 826         spin_lock(&efivars->lock);
 827         list_add(&new_efivar->list, &efivars->list);
 828         spin_unlock(&efivars->lock);
 829
 830         return 0;
 831 }
 832
 833 static int
 834 create_efivars_bin_attributes(struct efivars *efivars)
 835 {
 836         struct bin_attribute *attr;
 837         int error;
 838
 839         /* new_var */
 840         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 841         if (!attr)
 842                 return -ENOMEM;
 843
 844         attr->attr.name = "new_var";
 845         attr->attr.mode = 0200;
 846         attr->write = efivar_create;
 847         attr->private = efivars;
 848         efivars->new_var = attr;
 849
 850         /* del_var */
 851         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 852         if (!attr) {
 853                 error = -ENOMEM;
 854                 goto out_free;
 855         }
 856         attr->attr.name = "del_var";
 857         attr->attr.mode = 0200;
 858         attr->write = efivar_delete;
 859         attr->private = efivars;
 860         efivars->del_var = attr;
 861
 862         sysfs_bin_attr_init(efivars->new_var);
 863         sysfs_bin_attr_init(efivars->del_var);
 864
 865         /* Register */
 866         error = sysfs_create_bin_file(&efivars->kset->kobj,
 867                                       efivars->new_var);
 868         if (error) {
 869                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
 870                         " due to error %d\n", error);
 871                 goto out_free;
 872         }
 873         error = sysfs_create_bin_file(&efivars->kset->kobj,
 874                                       efivars->del_var);
 875         if (error) {
 876                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
 877                         " due to error %d\n", error);
 878                 sysfs_remove_bin_file(&efivars->kset->kobj,
 879                                       efivars->new_var);
 880                 goto out_free;
 881         }
 882
 883         return 0;
 884 out_free:
 885         kfree(efivars->del_var);
 886         efivars->del_var = NULL;
 887         kfree(efivars->new_var);
 888         efivars->new_var = NULL;
 889         return error;
 890 }
 891
 892 void unregister_efivars(struct efivars *efivars)
 893 {
 894         struct efivar_entry *entry, *n;
 895
 896         list_for_each_entry_safe(entry, n, &efivars->list, list) {
 897                 spin_lock(&efivars->lock);
 898                 list_del(&entry->list);
 899                 spin_unlock(&efivars->lock);
 900                 efivar_unregister(entry);
 901         }
 902         if (efivars->new_var)
 903                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
 904         if (efivars->del_var)
 905                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
 906         kfree(efivars->new_var);
 907         kfree(efivars->del_var);
 908         kset_unregister(efivars->kset);
 909 }
 910 EXPORT_SYMBOL_GPL(unregister_efivars);
 911
 912 int register_efivars(struct efivars *efivars,
 913                      const struct efivar_operations *ops,
 914                      struct kobject *parent_kobj)
 915 {
 916         efi_status_t status = EFI_NOT_FOUND;
 917         efi_guid_t vendor_guid;
 918         efi_char16_t *variable_name;
 919         unsigned long variable_name_size = 1024;
 920         int error = 0;
 921
 922         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
 923         if (!variable_name) {
 924                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
 925                 return -ENOMEM;
 926         }
 927
 928         spin_lock_init(&efivars->lock);
 929         INIT_LIST_HEAD(&efivars->list);
 930         efivars->ops = ops;
 931
 932         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
 933         if (!efivars->kset) {
 934                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 935                 error = -ENOMEM;
 936                 goto out;
 937         }
 938
 939         /*
 940          * Per EFI spec, the maximum storage allocated for both
 941          * the variable name and variable data is 1024 bytes.
 942          */
 943
 944         do {
 945                 variable_name_size = 1024;
 946
 947                 status = ops->get_next_variable(&variable_name_size,
 948                                                 variable_name,
 949                                                 &vendor_guid);
 950                 switch (status) {
 951                 case EFI_SUCCESS:
 952                         efivar_create_sysfs_entry(efivars,
 953                                                   variable_name_size,
 954                                                   variable_name,
 955                                                   &vendor_guid);
 956                         break;
 957                 case EFI_NOT_FOUND:
 958                         break;
 959                 default:
 960                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
 961                                 status);
 962                         status = EFI_NOT_FOUND;
 963                         break;
 964                 }
 965         } while (status != EFI_NOT_FOUND);
 966
 967         error = create_efivars_bin_attributes(efivars);
 968         if (error)
 969                 unregister_efivars(efivars);
 970
 971         efivars->efi_pstore_info = efi_pstore_info;
 972
 973         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
 974         if (efivars->efi_pstore_info.buf) {
 975                 efivars->efi_pstore_info.bufsize = 1024;
 976                 efivars->efi_pstore_info.data = efivars;
 977                 mutex_init(&efivars->efi_pstore_info.buf_mutex);
 978                 pstore_register(&efivars->efi_pstore_info);
 979         }
 980
 981 out:
 982         kfree(variable_name);
 983
 984         return error;
 985 }
 986 EXPORT_SYMBOL_GPL(register_efivars);
 987
 988 static struct efivars __efivars;
 989 static struct efivar_operations ops;
 990
 991 /*
 992  * For now we register the efi subsystem with the firmware subsystem
 993  * and the vars subsystem with the efi subsystem.  In the future, it
 994  * might make sense to split off the efi subsystem into its own
 995  * driver, but for now only efivars will register with it, so just
 996  * include it here.
 997  */
 998
 999 static int __init
1000 efivars_init(void)
1001 {
1002         int error = 0;
1003
1004         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1005                EFIVARS_DATE);
1006
1007         if (!efi_enabled)
1008                 return 0;
1009
1010         /* For now we'll register the efi directory at /sys/firmware/efi */
1011         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1012         if (!efi_kobj) {
1013                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1014                 return -ENOMEM;
1015         }
1016
1017         ops.get_variable = efi.get_variable;
1018         ops.set_variable = efi.set_variable;
1019         ops.get_next_variable = efi.get_next_variable;
1020         error = register_efivars(&__efivars, &ops, efi_kobj);
1021         if (error)
1022                 goto err_put;
1023
1024         /* Don't forget the systab entry */
1025         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1026         if (error) {
1027                 printk(KERN_ERR
1028                        "efivars: Sysfs attribute export failed with error %d.\n",
1029                        error);
1030                 goto err_unregister;
1031         }
1032
1033         return 0;
1034
1035 err_unregister:
1036         unregister_efivars(&__efivars);
1037 err_put:
1038         kobject_put(efi_kobj);
1039         return error;
1040 }
1041
1042 static void __exit
1043 efivars_exit(void)
1044 {
1045         if (efi_enabled) {
1046                 unregister_efivars(&__efivars);
1047                 kobject_put(efi_kobj);
1048         }
1049 }
1050
1051 module_init(efivars_init);
1052 module_exit(efivars_exit);
1053