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 #define PSTORE_EFI_ATTRIBUTES \
 126         (EFI_VARIABLE_NON_VOLATILE | \
 127          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 128          EFI_VARIABLE_RUNTIME_ACCESS)
 129
 130 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 131 struct efivar_attribute efivar_attr_##_name = { \
 132         .attr = {.name = __stringify(_name), .mode = _mode}, \
 133         .show = _show, \
 134         .store = _store, \
 135 };
 136
 137 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 138 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 139
 140 /*
 141  * Prototype for sysfs creation function
 142  */
 143 static int
 144 efivar_create_sysfs_entry(struct efivars *efivars,
 145                           unsigned long variable_name_size,
 146                           efi_char16_t *variable_name,
 147                           efi_guid_t *vendor_guid);
 148
 149 /* Return the number of unicode characters in data */
 150 static unsigned long
 151 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 152 {
 153         unsigned long length = 0;
 154
 155         while (*s++ != 0 && length < maxlength)
 156                 length++;
 157         return length;
 158 }
 159
 160 static inline unsigned long
 161 utf16_strlen(efi_char16_t *s)
 162 {
 163         return utf16_strnlen(s, ~0UL);
 164 }
 165
 166 /*
 167  * Return the number of bytes is the length of this string
 168  * Note: this is NOT the same as the number of unicode characters
 169  */
 170 static inline unsigned long
 171 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 172 {
 173         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 174 }
 175
 176 static inline int
 177 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 178 {
 179         while (1) {
 180                 if (len == 0)
 181                         return 0;
 182                 if (*a < *b)
 183                         return -1;
 184                 if (*a > *b)
 185                         return 1;
 186                 if (*a == 0) /* implies *b == 0 */
 187                         return 0;
 188                 a++;
 189                 b++;
 190                 len--;
 191         }
 192 }
 193
 194 static bool
 195 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 196                      unsigned long len)
 197 {
 198         struct efi_generic_dev_path *node;
 199         int offset = 0;
 200
 201         node = (struct efi_generic_dev_path *)buffer;
 202
 203         if (len < sizeof(*node))
 204                 return false;
 205
 206         while (offset <= len - sizeof(*node) &&
 207                node->length >= sizeof(*node) &&
 208                 node->length <= len - offset) {
 209                 offset += node->length;
 210
 211                 if ((node->type == EFI_DEV_END_PATH ||
 212                      node->type == EFI_DEV_END_PATH2) &&
 213                     node->sub_type == EFI_DEV_END_ENTIRE)
 214                         return true;
 215
 216                 node = (struct efi_generic_dev_path *)(buffer + offset);
 217         }
 218
 219         /*
 220          * If we're here then either node->length pointed past the end
 221          * of the buffer or we reached the end of the buffer without
 222          * finding a device path end node.
 223          */
 224         return false;
 225 }
 226
 227 static bool
 228 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 229                     unsigned long len)
 230 {
 231         /* An array of 16-bit integers */
 232         if ((len % 2) != 0)
 233                 return false;
 234
 235         return true;
 236 }
 237
 238 static bool
 239 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 240                      unsigned long len)
 241 {
 242         u16 filepathlength;
 243         int i, desclength = 0, namelen;
 244
 245         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 246
 247         /* Either "Boot" or "Driver" followed by four digits of hex */
 248         for (i = match; i < match+4; i++) {
 249                 if (var->VariableName[i] > 127 ||
 250                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 251                         return true;
 252         }
 253
 254         /* Reject it if there's 4 digits of hex and then further content */
 255         if (namelen > match + 4)
 256                 return false;
 257
 258         /* A valid entry must be at least 8 bytes */
 259         if (len < 8)
 260                 return false;
 261
 262         filepathlength = buffer[4] | buffer[5] << 8;
 263
 264         /*
 265          * There's no stored length for the description, so it has to be
 266          * found by hand
 267          */
 268         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 269
 270         /* Each boot entry must have a descriptor */
 271         if (!desclength)
 272                 return false;
 273
 274         /*
 275          * If the sum of the length of the description, the claimed filepath
 276          * length and the original header are greater than the length of the
 277          * variable, it's malformed
 278          */
 279         if ((desclength + filepathlength + 6) > len)
 280                 return false;
 281
 282         /*
 283          * And, finally, check the filepath
 284          */
 285         return validate_device_path(var, match, buffer + desclength + 6,
 286                                     filepathlength);
 287 }
 288
 289 static bool
 290 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 291                 unsigned long len)
 292 {
 293         /* A single 16-bit integer */
 294         if (len != 2)
 295                 return false;
 296
 297         return true;
 298 }
 299
 300 static bool
 301 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 302                       unsigned long len)
 303 {
 304         int i;
 305
 306         for (i = 0; i < len; i++) {
 307                 if (buffer[i] > 127)
 308                         return false;
 309
 310                 if (buffer[i] == 0)
 311                         return true;
 312         }
 313
 314         return false;
 315 }
 316
 317 struct variable_validate {
 318         char *name;
 319         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 320                          unsigned long len);
 321 };
 322
 323 static const struct variable_validate variable_validate[] = {
 324         { "BootNext", validate_uint16 },
 325         { "BootOrder", validate_boot_order },
 326         { "DriverOrder", validate_boot_order },
 327         { "Boot*", validate_load_option },
 328         { "Driver*", validate_load_option },
 329         { "ConIn", validate_device_path },
 330         { "ConInDev", validate_device_path },
 331         { "ConOut", validate_device_path },
 332         { "ConOutDev", validate_device_path },
 333         { "ErrOut", validate_device_path },
 334         { "ErrOutDev", validate_device_path },
 335         { "Timeout", validate_uint16 },
 336         { "Lang", validate_ascii_string },
 337         { "PlatformLang", validate_ascii_string },
 338         { "", NULL },
 339 };
 340
 341 static bool
 342 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 343 {
 344         int i;
 345         u16 *unicode_name = var->VariableName;
 346
 347         for (i = 0; variable_validate[i].validate != NULL; i++) {
 348                 const char *name = variable_validate[i].name;
 349                 int match;
 350
 351                 for (match = 0; ; match++) {
 352                         char c = name[match];
 353                         u16 u = unicode_name[match];
 354
 355                         /* All special variables are plain ascii */
 356                         if (u > 127)
 357                                 return true;
 358
 359                         /* Wildcard in the matching name means we've matched */
 360                         if (c == '*')
 361                                 return variable_validate[i].validate(var,
 362                                                              match, data, len);
 363
 364                         /* Case sensitive match */
 365                         if (c != u)
 366                                 break;
 367
 368                         /* Reached the end of the string while matching */
 369                         if (!c)
 370                                 return variable_validate[i].validate(var,
 371                                                              match, data, len);
 372                 }
 373         }
 374
 375         return true;
 376 }
 377
 378 static efi_status_t
 379 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 380 {
 381         efi_status_t status;
 382
 383         var->DataSize = 1024;
 384         status = efivars->ops->get_variable(var->VariableName,
 385                                             &var->VendorGuid,
 386                                             &var->Attributes,
 387                                             &var->DataSize,
 388                                             var->Data);
 389         return status;
 390 }
 391
 392 static efi_status_t
 393 get_var_data(struct efivars *efivars, struct efi_variable *var)
 394 {
 395         efi_status_t status;
 396
 397         spin_lock(&efivars->lock);
 398         status = get_var_data_locked(efivars, var);
 399         spin_unlock(&efivars->lock);
 400
 401         if (status != EFI_SUCCESS) {
 402                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 403                         status);
 404         }
 405         return status;
 406 }
 407
 408 static ssize_t
 409 efivar_guid_read(struct efivar_entry *entry, char *buf)
 410 {
 411         struct efi_variable *var = &entry->var;
 412         char *str = buf;
 413
 414         if (!entry || !buf)
 415                 return 0;
 416
 417         efi_guid_unparse(&var->VendorGuid, str);
 418         str += strlen(str);
 419         str += sprintf(str, "\n");
 420
 421         return str - buf;
 422 }
 423
 424 static ssize_t
 425 efivar_attr_read(struct efivar_entry *entry, char *buf)
 426 {
 427         struct efi_variable *var = &entry->var;
 428         char *str = buf;
 429         efi_status_t status;
 430
 431         if (!entry || !buf)
 432                 return -EINVAL;
 433
 434         status = get_var_data(entry->efivars, var);
 435         if (status != EFI_SUCCESS)
 436                 return -EIO;
 437
 438         if (var->Attributes & 0x1)
 439                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 440         if (var->Attributes & 0x2)
 441                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 442         if (var->Attributes & 0x4)
 443                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 444         return str - buf;
 445 }
 446
 447 static ssize_t
 448 efivar_size_read(struct efivar_entry *entry, char *buf)
 449 {
 450         struct efi_variable *var = &entry->var;
 451         char *str = buf;
 452         efi_status_t status;
 453
 454         if (!entry || !buf)
 455                 return -EINVAL;
 456
 457         status = get_var_data(entry->efivars, var);
 458         if (status != EFI_SUCCESS)
 459                 return -EIO;
 460
 461         str += sprintf(str, "0x%lx\n", var->DataSize);
 462         return str - buf;
 463 }
 464
 465 static ssize_t
 466 efivar_data_read(struct efivar_entry *entry, char *buf)
 467 {
 468         struct efi_variable *var = &entry->var;
 469         efi_status_t status;
 470
 471         if (!entry || !buf)
 472                 return -EINVAL;
 473
 474         status = get_var_data(entry->efivars, var);
 475         if (status != EFI_SUCCESS)
 476                 return -EIO;
 477
 478         memcpy(buf, var->Data, var->DataSize);
 479         return var->DataSize;
 480 }
 481 /*
 482  * We allow each variable to be edited via rewriting the
 483  * entire efi variable structure.
 484  */
 485 static ssize_t
 486 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 487 {
 488         struct efi_variable *new_var, *var = &entry->var;
 489         struct efivars *efivars = entry->efivars;
 490         efi_status_t status = EFI_NOT_FOUND;
 491
 492         if (count != sizeof(struct efi_variable))
 493                 return -EINVAL;
 494
 495         new_var = (struct efi_variable *)buf;
 496         /*
 497          * If only updating the variable data, then the name
 498          * and guid should remain the same
 499          */
 500         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 501                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 502                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 503                 return -EINVAL;
 504         }
 505
 506         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 507                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 508                 return -EINVAL;
 509         }
 510
 511         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 512             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 513                 printk(KERN_ERR "efivars: Malformed variable content\n");
 514                 return -EINVAL;
 515         }
 516
 517         spin_lock(&efivars->lock);
 518         status = efivars->ops->set_variable(new_var->VariableName,
 519                                             &new_var->VendorGuid,
 520                                             new_var->Attributes,
 521                                             new_var->DataSize,
 522                                             new_var->Data);
 523
 524         spin_unlock(&efivars->lock);
 525
 526         if (status != EFI_SUCCESS) {
 527                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 528                         status);
 529                 return -EIO;
 530         }
 531
 532         memcpy(&entry->var, new_var, count);
 533         return count;
 534 }
 535
 536 static ssize_t
 537 efivar_show_raw(struct efivar_entry *entry, char *buf)
 538 {
 539         struct efi_variable *var = &entry->var;
 540         efi_status_t status;
 541
 542         if (!entry || !buf)
 543                 return 0;
 544
 545         status = get_var_data(entry->efivars, var);
 546         if (status != EFI_SUCCESS)
 547                 return -EIO;
 548
 549         memcpy(buf, var, sizeof(*var));
 550         return sizeof(*var);
 551 }
 552
 553 /*
 554  * Generic read/write functions that call the specific functions of
 555  * the attributes...
 556  */
 557 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 558                                 char *buf)
 559 {
 560         struct efivar_entry *var = to_efivar_entry(kobj);
 561         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 562         ssize_t ret = -EIO;
 563
 564         if (!capable(CAP_SYS_ADMIN))
 565                 return -EACCES;
 566
 567         if (efivar_attr->show) {
 568                 ret = efivar_attr->show(var, buf);
 569         }
 570         return ret;
 571 }
 572
 573 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 574                                 const char *buf, size_t count)
 575 {
 576         struct efivar_entry *var = to_efivar_entry(kobj);
 577         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 578         ssize_t ret = -EIO;
 579
 580         if (!capable(CAP_SYS_ADMIN))
 581                 return -EACCES;
 582
 583         if (efivar_attr->store)
 584                 ret = efivar_attr->store(var, buf, count);
 585
 586         return ret;
 587 }
 588
 589 static const struct sysfs_ops efivar_attr_ops = {
 590         .show = efivar_attr_show,
 591         .store = efivar_attr_store,
 592 };
 593
 594 static void efivar_release(struct kobject *kobj)
 595 {
 596         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 597         kfree(var);
 598 }
 599
 600 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 601 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 602 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 603 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 604 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 605
 606 static struct attribute *def_attrs[] = {
 607         &efivar_attr_guid.attr,
 608         &efivar_attr_size.attr,
 609         &efivar_attr_attributes.attr,
 610         &efivar_attr_data.attr,
 611         &efivar_attr_raw_var.attr,
 612         NULL,
 613 };
 614
 615 static struct kobj_type efivar_ktype = {
 616         .release = efivar_release,
 617         .sysfs_ops = &efivar_attr_ops,
 618         .default_attrs = def_attrs,
 619 };
 620
 621 static struct pstore_info efi_pstore_info;
 622
 623 static inline void
 624 efivar_unregister(struct efivar_entry *var)
 625 {
 626         kobject_put(&var->kobj);
 627 }
 628
 629 #ifdef CONFIG_PSTORE
 630
 631 static int efi_pstore_open(struct pstore_info *psi)
 632 {
 633         struct efivars *efivars = psi->data;
 634
 635         spin_lock(&efivars->lock);
 636         efivars->walk_entry = list_first_entry(&efivars->list,
 637                                                struct efivar_entry, list);
 638         return 0;
 639 }
 640
 641 static int efi_pstore_close(struct pstore_info *psi)
 642 {
 643         struct efivars *efivars = psi->data;
 644
 645         spin_unlock(&efivars->lock);
 646         return 0;
 647 }
 648
 649 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 650                                struct timespec *timespec,
 651                                char **buf, struct pstore_info *psi)
 652 {
 653         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 654         struct efivars *efivars = psi->data;
 655         char name[DUMP_NAME_LEN];
 656         int i;
 657         unsigned int part, size;
 658         unsigned long time;
 659
 660         while (&efivars->walk_entry->list != &efivars->list) {
 661                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 662                                  vendor)) {
 663                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 664                                 name[i] = efivars->walk_entry->var.VariableName[i];
 665                         }
 666                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 667                                 *id = part;
 668                                 timespec->tv_sec = time;
 669                                 timespec->tv_nsec = 0;
 670                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 671                                 size = efivars->walk_entry->var.DataSize;
 672                                 *buf = kmalloc(size, GFP_KERNEL);
 673                                 if (*buf == NULL)
 674                                         return -ENOMEM;
 675                                 memcpy(*buf, efivars->walk_entry->var.Data,
 676                                        size);
 677                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 678                                                    struct efivar_entry, list);
 679                                 return size;
 680                         }
 681                 }
 682                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 683                                                  struct efivar_entry, list);
 684         }
 685         return 0;
 686 }
 687
 688 static int efi_pstore_write(enum pstore_type_id type,
 689                 enum kmsg_dump_reason reason, u64 *id,
 690                 unsigned int part, size_t size, struct pstore_info *psi)
 691 {
 692         char name[DUMP_NAME_LEN];
 693         char stub_name[DUMP_NAME_LEN];
 694         efi_char16_t efi_name[DUMP_NAME_LEN];
 695         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 696         struct efivars *efivars = psi->data;
 697         struct efivar_entry *entry, *found = NULL;
 698         int i, ret = 0;
 699
 700         sprintf(stub_name, "dump-type%u-%u-", type, part);
 701         sprintf(name, "%s%lu", stub_name, get_seconds());
 702
 703         spin_lock(&efivars->lock);
 704
 705         for (i = 0; i < DUMP_NAME_LEN; i++)
 706                 efi_name[i] = stub_name[i];
 707
 708         /*
 709          * Clean up any entries with the same name
 710          */
 711
 712         list_for_each_entry(entry, &efivars->list, list) {
 713                 get_var_data_locked(efivars, &entry->var);
 714
 715                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
 716                         continue;
 717                 if (utf16_strncmp(entry->var.VariableName, efi_name,
 718                                   utf16_strlen(efi_name)))
 719                         continue;
 720                 /* Needs to be a prefix */
 721                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 722                         continue;
 723
 724                 /* found */
 725                 found = entry;
 726                 efivars->ops->set_variable(entry->var.VariableName,
 727                                            &entry->var.VendorGuid,
 728                                            PSTORE_EFI_ATTRIBUTES,
 729                                            0, NULL);
 730         }
 731
 732         if (found)
 733                 list_del(&found->list);
 734
 735         for (i = 0; i < DUMP_NAME_LEN; i++)
 736                 efi_name[i] = name[i];
 737
 738         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 739                                    size, psi->buf);
 740
 741         spin_unlock(&efivars->lock);
 742
 743         if (found)
 744                 efivar_unregister(found);
 745
 746         if (size)
 747                 ret = efivar_create_sysfs_entry(efivars,
 748                                           utf16_strsize(efi_name,
 749                                                         DUMP_NAME_LEN * 2),
 750                                           efi_name, &vendor);
 751
 752         *id = part;
 753         return ret;
 754 };
 755
 756 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 757                             struct pstore_info *psi)
 758 {
 759         efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
 760
 761         return 0;
 762 }
 763 #else
 764 static int efi_pstore_open(struct pstore_info *psi)
 765 {
 766         return 0;
 767 }
 768
 769 static int efi_pstore_close(struct pstore_info *psi)
 770 {
 771         return 0;
 772 }
 773
 774 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 775                                struct timespec *timespec,
 776                                char **buf, struct pstore_info *psi)
 777 {
 778         return -1;
 779 }
 780
 781 static int efi_pstore_write(enum pstore_type_id type,
 782                 enum kmsg_dump_reason reason, u64 *id,
 783                 unsigned int part, size_t size, struct pstore_info *psi)
 784 {
 785         return 0;
 786 }
 787
 788 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 789                             struct pstore_info *psi)
 790 {
 791         return 0;
 792 }
 793 #endif
 794
 795 static struct pstore_info efi_pstore_info = {
 796         .owner          = THIS_MODULE,
 797         .name           = "efi",
 798         .open           = efi_pstore_open,
 799         .close          = efi_pstore_close,
 800         .read           = efi_pstore_read,
 801         .write          = efi_pstore_write,
 802         .erase          = efi_pstore_erase,
 803 };
 804
 805 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 806                              struct bin_attribute *bin_attr,
 807                              char *buf, loff_t pos, size_t count)
 808 {
 809         struct efi_variable *new_var = (struct efi_variable *)buf;
 810         struct efivars *efivars = bin_attr->private;
 811         struct efivar_entry *search_efivar, *n;
 812         unsigned long strsize1, strsize2;
 813         efi_status_t status = EFI_NOT_FOUND;
 814         int found = 0;
 815
 816         if (!capable(CAP_SYS_ADMIN))
 817                 return -EACCES;
 818
 819         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 820             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 821                 printk(KERN_ERR "efivars: Malformed variable content\n");
 822                 return -EINVAL;
 823         }
 824
 825         spin_lock(&efivars->lock);
 826
 827         /*
 828          * Does this variable already exist?
 829          */
 830         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 831                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 832                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
 833                 if (strsize1 == strsize2 &&
 834                         !memcmp(&(search_efivar->var.VariableName),
 835                                 new_var->VariableName, strsize1) &&
 836                         !efi_guidcmp(search_efivar->var.VendorGuid,
 837                                 new_var->VendorGuid)) {
 838                         found = 1;
 839                         break;
 840                 }
 841         }
 842         if (found) {
 843                 spin_unlock(&efivars->lock);
 844                 return -EINVAL;
 845         }
 846
 847         /* now *really* create the variable via EFI */
 848         status = efivars->ops->set_variable(new_var->VariableName,
 849                                             &new_var->VendorGuid,
 850                                             new_var->Attributes,
 851                                             new_var->DataSize,
 852                                             new_var->Data);
 853
 854         if (status != EFI_SUCCESS) {
 855                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 856                         status);
 857                 spin_unlock(&efivars->lock);
 858                 return -EIO;
 859         }
 860         spin_unlock(&efivars->lock);
 861
 862         /* Create the entry in sysfs.  Locking is not required here */
 863         status = efivar_create_sysfs_entry(efivars,
 864                                            utf16_strsize(new_var->VariableName,
 865                                                          1024),
 866                                            new_var->VariableName,
 867                                            &new_var->VendorGuid);
 868         if (status) {
 869                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 870         }
 871         return count;
 872 }
 873
 874 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 875                              struct bin_attribute *bin_attr,
 876                              char *buf, loff_t pos, size_t count)
 877 {
 878         struct efi_variable *del_var = (struct efi_variable *)buf;
 879         struct efivars *efivars = bin_attr->private;
 880         struct efivar_entry *search_efivar, *n;
 881         unsigned long strsize1, strsize2;
 882         efi_status_t status = EFI_NOT_FOUND;
 883         int found = 0;
 884
 885         if (!capable(CAP_SYS_ADMIN))
 886                 return -EACCES;
 887
 888         spin_lock(&efivars->lock);
 889
 890         /*
 891          * Does this variable already exist?
 892          */
 893         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 894                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 895                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
 896                 if (strsize1 == strsize2 &&
 897                         !memcmp(&(search_efivar->var.VariableName),
 898                                 del_var->VariableName, strsize1) &&
 899                         !efi_guidcmp(search_efivar->var.VendorGuid,
 900                                 del_var->VendorGuid)) {
 901                         found = 1;
 902                         break;
 903                 }
 904         }
 905         if (!found) {
 906                 spin_unlock(&efivars->lock);
 907                 return -EINVAL;
 908         }
 909         /* force the Attributes/DataSize to 0 to ensure deletion */
 910         del_var->Attributes = 0;
 911         del_var->DataSize = 0;
 912
 913         status = efivars->ops->set_variable(del_var->VariableName,
 914                                             &del_var->VendorGuid,
 915                                             del_var->Attributes,
 916                                             del_var->DataSize,
 917                                             del_var->Data);
 918
 919         if (status != EFI_SUCCESS) {
 920                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 921                         status);
 922                 spin_unlock(&efivars->lock);
 923                 return -EIO;
 924         }
 925         list_del(&search_efivar->list);
 926         /* We need to release this lock before unregistering. */
 927         spin_unlock(&efivars->lock);
 928         efivar_unregister(search_efivar);
 929
 930         /* It's dead Jim.... */
 931         return count;
 932 }
 933
 934 /*
 935  * Let's not leave out systab information that snuck into
 936  * the efivars driver
 937  */
 938 static ssize_t systab_show(struct kobject *kobj,
 939                            struct kobj_attribute *attr, char *buf)
 940 {
 941         char *str = buf;
 942
 943         if (!kobj || !buf)
 944                 return -EINVAL;
 945
 946         if (efi.mps != EFI_INVALID_TABLE_ADDR)
 947                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 948         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 949                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 950         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 951                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 952         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 953                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 954         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 955                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 956         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 957                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 958         if (efi.uga != EFI_INVALID_TABLE_ADDR)
 959                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 960
 961         return str - buf;
 962 }
 963
 964 static struct kobj_attribute efi_attr_systab =
 965                         __ATTR(systab, 0400, systab_show, NULL);
 966
 967 static struct attribute *efi_subsys_attrs[] = {
 968         &efi_attr_systab.attr,
 969         NULL,   /* maybe more in the future? */
 970 };
 971
 972 static struct attribute_group efi_subsys_attr_group = {
 973         .attrs = efi_subsys_attrs,
 974 };
 975
 976 static struct kobject *efi_kobj;
 977
 978 /*
 979  * efivar_create_sysfs_entry()
 980  * Requires:
 981  *    variable_name_size = number of bytes required to hold
 982  *                         variable_name (not counting the NULL
 983  *                         character at the end.
 984  *    efivars->lock is not held on entry or exit.
 985  * Returns 1 on failure, 0 on success
 986  */
 987 static int
 988 efivar_create_sysfs_entry(struct efivars *efivars,
 989                           unsigned long variable_name_size,
 990                           efi_char16_t *variable_name,
 991                           efi_guid_t *vendor_guid)
 992 {
 993         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 994         char *short_name;
 995         struct efivar_entry *new_efivar;
 996
 997         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 998         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 999
1000         if (!short_name || !new_efivar)  {
1001                 kfree(short_name);
1002                 kfree(new_efivar);
1003                 return 1;
1004         }
1005
1006         new_efivar->efivars = efivars;
1007         memcpy(new_efivar->var.VariableName, variable_name,
1008                 variable_name_size);
1009         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1010
1011         /* Convert Unicode to normal chars (assume top bits are 0),
1012            ala UTF-8 */
1013         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1014                 short_name[i] = variable_name[i] & 0xFF;
1015         }
1016         /* This is ugly, but necessary to separate one vendor's
1017            private variables from another's.         */
1018
1019         *(short_name + strlen(short_name)) = '-';
1020         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1021
1022         new_efivar->kobj.kset = efivars->kset;
1023         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1024                                  "%s", short_name);
1025         if (i) {
1026                 kfree(short_name);
1027                 kfree(new_efivar);
1028                 return 1;
1029         }
1030
1031         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1032         kfree(short_name);
1033         short_name = NULL;
1034
1035         spin_lock(&efivars->lock);
1036         list_add(&new_efivar->list, &efivars->list);
1037         spin_unlock(&efivars->lock);
1038
1039         return 0;
1040 }
1041
1042 static int
1043 create_efivars_bin_attributes(struct efivars *efivars)
1044 {
1045         struct bin_attribute *attr;
1046         int error;
1047
1048         /* new_var */
1049         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1050         if (!attr)
1051                 return -ENOMEM;
1052
1053         attr->attr.name = "new_var";
1054         attr->attr.mode = 0200;
1055         attr->write = efivar_create;
1056         attr->private = efivars;
1057         efivars->new_var = attr;
1058
1059         /* del_var */
1060         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1061         if (!attr) {
1062                 error = -ENOMEM;
1063                 goto out_free;
1064         }
1065         attr->attr.name = "del_var";
1066         attr->attr.mode = 0200;
1067         attr->write = efivar_delete;
1068         attr->private = efivars;
1069         efivars->del_var = attr;
1070
1071         sysfs_bin_attr_init(efivars->new_var);
1072         sysfs_bin_attr_init(efivars->del_var);
1073
1074         /* Register */
1075         error = sysfs_create_bin_file(&efivars->kset->kobj,
1076                                       efivars->new_var);
1077         if (error) {
1078                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1079                         " due to error %d\n", error);
1080                 goto out_free;
1081         }
1082         error = sysfs_create_bin_file(&efivars->kset->kobj,
1083                                       efivars->del_var);
1084         if (error) {
1085                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1086                         " due to error %d\n", error);
1087                 sysfs_remove_bin_file(&efivars->kset->kobj,
1088                                       efivars->new_var);
1089                 goto out_free;
1090         }
1091
1092         return 0;
1093 out_free:
1094         kfree(efivars->del_var);
1095         efivars->del_var = NULL;
1096         kfree(efivars->new_var);
1097         efivars->new_var = NULL;
1098         return error;
1099 }
1100
1101 void unregister_efivars(struct efivars *efivars)
1102 {
1103         struct efivar_entry *entry, *n;
1104
1105         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1106                 spin_lock(&efivars->lock);
1107                 list_del(&entry->list);
1108                 spin_unlock(&efivars->lock);
1109                 efivar_unregister(entry);
1110         }
1111         if (efivars->new_var)
1112                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1113         if (efivars->del_var)
1114                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1115         kfree(efivars->new_var);
1116         kfree(efivars->del_var);
1117         kset_unregister(efivars->kset);
1118 }
1119 EXPORT_SYMBOL_GPL(unregister_efivars);
1120
1121 int register_efivars(struct efivars *efivars,
1122                      const struct efivar_operations *ops,
1123                      struct kobject *parent_kobj)
1124 {
1125         efi_status_t status = EFI_NOT_FOUND;
1126         efi_guid_t vendor_guid;
1127         efi_char16_t *variable_name;
1128         unsigned long variable_name_size = 1024;
1129         int error = 0;
1130
1131         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1132         if (!variable_name) {
1133                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1134                 return -ENOMEM;
1135         }
1136
1137         spin_lock_init(&efivars->lock);
1138         INIT_LIST_HEAD(&efivars->list);
1139         efivars->ops = ops;
1140
1141         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1142         if (!efivars->kset) {
1143                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1144                 error = -ENOMEM;
1145                 goto out;
1146         }
1147
1148         /*
1149          * Per EFI spec, the maximum storage allocated for both
1150          * the variable name and variable data is 1024 bytes.
1151          */
1152
1153         do {
1154                 variable_name_size = 1024;
1155
1156                 status = ops->get_next_variable(&variable_name_size,
1157                                                 variable_name,
1158                                                 &vendor_guid);
1159                 switch (status) {
1160                 case EFI_SUCCESS:
1161                         efivar_create_sysfs_entry(efivars,
1162                                                   variable_name_size,
1163                                                   variable_name,
1164                                                   &vendor_guid);
1165                         break;
1166                 case EFI_NOT_FOUND:
1167                         break;
1168                 default:
1169                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1170                                 status);
1171                         status = EFI_NOT_FOUND;
1172                         break;
1173                 }
1174         } while (status != EFI_NOT_FOUND);
1175
1176         error = create_efivars_bin_attributes(efivars);
1177         if (error)
1178                 unregister_efivars(efivars);
1179
1180         efivars->efi_pstore_info = efi_pstore_info;
1181
1182         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1183         if (efivars->efi_pstore_info.buf) {
1184                 efivars->efi_pstore_info.bufsize = 1024;
1185                 efivars->efi_pstore_info.data = efivars;
1186                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1187                 pstore_register(&efivars->efi_pstore_info);
1188         }
1189
1190 out:
1191         kfree(variable_name);
1192
1193         return error;
1194 }
1195 EXPORT_SYMBOL_GPL(register_efivars);
1196
1197 static struct efivars __efivars;
1198 static struct efivar_operations ops;
1199
1200 /*
1201  * For now we register the efi subsystem with the firmware subsystem
1202  * and the vars subsystem with the efi subsystem.  In the future, it
1203  * might make sense to split off the efi subsystem into its own
1204  * driver, but for now only efivars will register with it, so just
1205  * include it here.
1206  */
1207
1208 static int __init
1209 efivars_init(void)
1210 {
1211         int error = 0;
1212
1213         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1214                EFIVARS_DATE);
1215
1216         if (!efi_enabled)
1217                 return 0;
1218
1219         /* For now we'll register the efi directory at /sys/firmware/efi */
1220         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1221         if (!efi_kobj) {
1222                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1223                 return -ENOMEM;
1224         }
1225
1226         ops.get_variable = efi.get_variable;
1227         ops.set_variable = efi.set_variable;
1228         ops.get_next_variable = efi.get_next_variable;
1229         error = register_efivars(&__efivars, &ops, efi_kobj);
1230         if (error)
1231                 goto err_put;
1232
1233         /* Don't forget the systab entry */
1234         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1235         if (error) {
1236                 printk(KERN_ERR
1237                        "efivars: Sysfs attribute export failed with error %d.\n",
1238                        error);
1239                 goto err_unregister;
1240         }
1241
1242         return 0;
1243
1244 err_unregister:
1245         unregister_efivars(&__efivars);
1246 err_put:
1247         kobject_put(efi_kobj);
1248         return error;
1249 }
1250
1251 static void __exit
1252 efivars_exit(void)
1253 {
1254         if (efi_enabled) {
1255                 unregister_efivars(&__efivars);
1256                 kobject_put(efi_kobj);
1257         }
1258 }
1259
1260 module_init(efivars_init);
1261 module_exit(efivars_exit);
1262