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 <linux/fs.h>
  84 #include <linux/ramfs.h>
  85 #include <linux/pagemap.h>
  86
  87 #include <asm/uaccess.h>
  88
  89 #define EFIVARS_VERSION "0.08"
  90 #define EFIVARS_DATE "2004-May-17"
  91
  92 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  93 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  94 MODULE_LICENSE("GPL");
  95 MODULE_VERSION(EFIVARS_VERSION);
  96
  97 #define DUMP_NAME_LEN 52
  98
  99 /*
 100  * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
 101  * not including trailing NUL
 102  */
 103 #define GUID_LEN 36
 104
 105 /*
 106  * The maximum size of VariableName + Data = 1024
 107  * Therefore, it's reasonable to save that much
 108  * space in each part of the structure,
 109  * and we use a page for reading/writing.
 110  */
 111
 112 struct efi_variable {
 113         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 114         efi_guid_t    VendorGuid;
 115         unsigned long DataSize;
 116         __u8          Data[1024];
 117         efi_status_t  Status;
 118         __u32         Attributes;
 119 } __attribute__((packed));
 120
 121 struct efivar_entry {
 122         struct efivars *efivars;
 123         struct efi_variable var;
 124         struct list_head list;
 125         struct kobject kobj;
 126 };
 127
 128 struct efivar_attribute {
 129         struct attribute attr;
 130         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 131         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 132 };
 133
 134 static struct efivars __efivars;
 135 static struct efivar_operations ops;
 136
 137 #define PSTORE_EFI_ATTRIBUTES \
 138         (EFI_VARIABLE_NON_VOLATILE | \
 139          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 140          EFI_VARIABLE_RUNTIME_ACCESS)
 141
 142 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 143 struct efivar_attribute efivar_attr_##_name = { \
 144         .attr = {.name = __stringify(_name), .mode = _mode}, \
 145         .show = _show, \
 146         .store = _store, \
 147 };
 148
 149 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 150 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 151
 152 /*
 153  * Prototype for sysfs creation function
 154  */
 155 static int
 156 efivar_create_sysfs_entry(struct efivars *efivars,
 157                           unsigned long variable_name_size,
 158                           efi_char16_t *variable_name,
 159                           efi_guid_t *vendor_guid);
 160
 161 /*
 162  * Prototype for workqueue functions updating sysfs entry
 163  */
 164
 165 static void efivar_update_sysfs_entries(struct work_struct *);
 166 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
 167
 168 /* Return the number of unicode characters in data */
 169 static unsigned long
 170 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 171 {
 172         unsigned long length = 0;
 173
 174         while (*s++ != 0 && length < maxlength)
 175                 length++;
 176         return length;
 177 }
 178
 179 static inline unsigned long
 180 utf16_strlen(efi_char16_t *s)
 181 {
 182         return utf16_strnlen(s, ~0UL);
 183 }
 184
 185 /*
 186  * Return the number of bytes is the length of this string
 187  * Note: this is NOT the same as the number of unicode characters
 188  */
 189 static inline unsigned long
 190 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 191 {
 192         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 193 }
 194
 195 static inline int
 196 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 197 {
 198         while (1) {
 199                 if (len == 0)
 200                         return 0;
 201                 if (*a < *b)
 202                         return -1;
 203                 if (*a > *b)
 204                         return 1;
 205                 if (*a == 0) /* implies *b == 0 */
 206                         return 0;
 207                 a++;
 208                 b++;
 209                 len--;
 210         }
 211 }
 212
 213 static bool
 214 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 215                      unsigned long len)
 216 {
 217         struct efi_generic_dev_path *node;
 218         int offset = 0;
 219
 220         node = (struct efi_generic_dev_path *)buffer;
 221
 222         if (len < sizeof(*node))
 223                 return false;
 224
 225         while (offset <= len - sizeof(*node) &&
 226                node->length >= sizeof(*node) &&
 227                 node->length <= len - offset) {
 228                 offset += node->length;
 229
 230                 if ((node->type == EFI_DEV_END_PATH ||
 231                      node->type == EFI_DEV_END_PATH2) &&
 232                     node->sub_type == EFI_DEV_END_ENTIRE)
 233                         return true;
 234
 235                 node = (struct efi_generic_dev_path *)(buffer + offset);
 236         }
 237
 238         /*
 239          * If we're here then either node->length pointed past the end
 240          * of the buffer or we reached the end of the buffer without
 241          * finding a device path end node.
 242          */
 243         return false;
 244 }
 245
 246 static bool
 247 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 248                     unsigned long len)
 249 {
 250         /* An array of 16-bit integers */
 251         if ((len % 2) != 0)
 252                 return false;
 253
 254         return true;
 255 }
 256
 257 static bool
 258 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 259                      unsigned long len)
 260 {
 261         u16 filepathlength;
 262         int i, desclength = 0, namelen;
 263
 264         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 265
 266         /* Either "Boot" or "Driver" followed by four digits of hex */
 267         for (i = match; i < match+4; i++) {
 268                 if (var->VariableName[i] > 127 ||
 269                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
 270                         return true;
 271         }
 272
 273         /* Reject it if there's 4 digits of hex and then further content */
 274         if (namelen > match + 4)
 275                 return false;
 276
 277         /* A valid entry must be at least 8 bytes */
 278         if (len < 8)
 279                 return false;
 280
 281         filepathlength = buffer[4] | buffer[5] << 8;
 282
 283         /*
 284          * There's no stored length for the description, so it has to be
 285          * found by hand
 286          */
 287         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 288
 289         /* Each boot entry must have a descriptor */
 290         if (!desclength)
 291                 return false;
 292
 293         /*
 294          * If the sum of the length of the description, the claimed filepath
 295          * length and the original header are greater than the length of the
 296          * variable, it's malformed
 297          */
 298         if ((desclength + filepathlength + 6) > len)
 299                 return false;
 300
 301         /*
 302          * And, finally, check the filepath
 303          */
 304         return validate_device_path(var, match, buffer + desclength + 6,
 305                                     filepathlength);
 306 }
 307
 308 static bool
 309 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 310                 unsigned long len)
 311 {
 312         /* A single 16-bit integer */
 313         if (len != 2)
 314                 return false;
 315
 316         return true;
 317 }
 318
 319 static bool
 320 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 321                       unsigned long len)
 322 {
 323         int i;
 324
 325         for (i = 0; i < len; i++) {
 326                 if (buffer[i] > 127)
 327                         return false;
 328
 329                 if (buffer[i] == 0)
 330                         return true;
 331         }
 332
 333         return false;
 334 }
 335
 336 struct variable_validate {
 337         char *name;
 338         bool (*validate)(struct efi_variable *var, int match, u8 *data,
 339                          unsigned long len);
 340 };
 341
 342 static const struct variable_validate variable_validate[] = {
 343         { "BootNext", validate_uint16 },
 344         { "BootOrder", validate_boot_order },
 345         { "DriverOrder", validate_boot_order },
 346         { "Boot*", validate_load_option },
 347         { "Driver*", validate_load_option },
 348         { "ConIn", validate_device_path },
 349         { "ConInDev", validate_device_path },
 350         { "ConOut", validate_device_path },
 351         { "ConOutDev", validate_device_path },
 352         { "ErrOut", validate_device_path },
 353         { "ErrOutDev", validate_device_path },
 354         { "Timeout", validate_uint16 },
 355         { "Lang", validate_ascii_string },
 356         { "PlatformLang", validate_ascii_string },
 357         { "", NULL },
 358 };
 359
 360 static bool
 361 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 362 {
 363         int i;
 364         u16 *unicode_name = var->VariableName;
 365
 366         for (i = 0; variable_validate[i].validate != NULL; i++) {
 367                 const char *name = variable_validate[i].name;
 368                 int match;
 369
 370                 for (match = 0; ; match++) {
 371                         char c = name[match];
 372                         u16 u = unicode_name[match];
 373
 374                         /* All special variables are plain ascii */
 375                         if (u > 127)
 376                                 return true;
 377
 378                         /* Wildcard in the matching name means we've matched */
 379                         if (c == '*')
 380                                 return variable_validate[i].validate(var,
 381                                                              match, data, len);
 382
 383                         /* Case sensitive match */
 384                         if (c != u)
 385                                 break;
 386
 387                         /* Reached the end of the string while matching */
 388                         if (!c)
 389                                 return variable_validate[i].validate(var,
 390                                                              match, data, len);
 391                 }
 392         }
 393
 394         return true;
 395 }
 396
 397 static efi_status_t
 398 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 399 {
 400         efi_status_t status;
 401
 402         var->DataSize = 1024;
 403         status = efivars->ops->get_variable(var->VariableName,
 404                                             &var->VendorGuid,
 405                                             &var->Attributes,
 406                                             &var->DataSize,
 407                                             var->Data);
 408         return status;
 409 }
 410
 411 static efi_status_t
 412 get_var_data(struct efivars *efivars, struct efi_variable *var)
 413 {
 414         efi_status_t status;
 415         unsigned long flags;
 416
 417         spin_lock_irqsave(&efivars->lock, flags);
 418         status = get_var_data_locked(efivars, var);
 419         spin_unlock_irqrestore(&efivars->lock, flags);
 420
 421         if (status != EFI_SUCCESS) {
 422                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 423                         status);
 424         }
 425         return status;
 426 }
 427
 428 static ssize_t
 429 efivar_guid_read(struct efivar_entry *entry, char *buf)
 430 {
 431         struct efi_variable *var = &entry->var;
 432         char *str = buf;
 433
 434         if (!entry || !buf)
 435                 return 0;
 436
 437         efi_guid_unparse(&var->VendorGuid, str);
 438         str += strlen(str);
 439         str += sprintf(str, "\n");
 440
 441         return str - buf;
 442 }
 443
 444 static ssize_t
 445 efivar_attr_read(struct efivar_entry *entry, char *buf)
 446 {
 447         struct efi_variable *var = &entry->var;
 448         char *str = buf;
 449         efi_status_t status;
 450
 451         if (!entry || !buf)
 452                 return -EINVAL;
 453
 454         status = get_var_data(entry->efivars, var);
 455         if (status != EFI_SUCCESS)
 456                 return -EIO;
 457
 458         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 459                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 460         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 461                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 462         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 463                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 464         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 465                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 466         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 467                 str += sprintf(str,
 468                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 469         if (var->Attributes &
 470                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 471                 str += sprintf(str,
 472                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 473         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 474                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 475         return str - buf;
 476 }
 477
 478 static ssize_t
 479 efivar_size_read(struct efivar_entry *entry, char *buf)
 480 {
 481         struct efi_variable *var = &entry->var;
 482         char *str = buf;
 483         efi_status_t status;
 484
 485         if (!entry || !buf)
 486                 return -EINVAL;
 487
 488         status = get_var_data(entry->efivars, var);
 489         if (status != EFI_SUCCESS)
 490                 return -EIO;
 491
 492         str += sprintf(str, "0x%lx\n", var->DataSize);
 493         return str - buf;
 494 }
 495
 496 static ssize_t
 497 efivar_data_read(struct efivar_entry *entry, char *buf)
 498 {
 499         struct efi_variable *var = &entry->var;
 500         efi_status_t status;
 501
 502         if (!entry || !buf)
 503                 return -EINVAL;
 504
 505         status = get_var_data(entry->efivars, var);
 506         if (status != EFI_SUCCESS)
 507                 return -EIO;
 508
 509         memcpy(buf, var->Data, var->DataSize);
 510         return var->DataSize;
 511 }
 512 /*
 513  * We allow each variable to be edited via rewriting the
 514  * entire efi variable structure.
 515  */
 516 static ssize_t
 517 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 518 {
 519         struct efi_variable *new_var, *var = &entry->var;
 520         struct efivars *efivars = entry->efivars;
 521         efi_status_t status = EFI_NOT_FOUND;
 522
 523         if (count != sizeof(struct efi_variable))
 524                 return -EINVAL;
 525
 526         new_var = (struct efi_variable *)buf;
 527         /*
 528          * If only updating the variable data, then the name
 529          * and guid should remain the same
 530          */
 531         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 532                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 533                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 534                 return -EINVAL;
 535         }
 536
 537         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 538                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 539                 return -EINVAL;
 540         }
 541
 542         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 543             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 544                 printk(KERN_ERR "efivars: Malformed variable content\n");
 545                 return -EINVAL;
 546         }
 547
 548         spin_lock_irq(&efivars->lock);
 549         status = efivars->ops->set_variable(new_var->VariableName,
 550                                             &new_var->VendorGuid,
 551                                             new_var->Attributes,
 552                                             new_var->DataSize,
 553                                             new_var->Data);
 554
 555         spin_unlock_irq(&efivars->lock);
 556
 557         if (status != EFI_SUCCESS) {
 558                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 559                         status);
 560                 return -EIO;
 561         }
 562
 563         memcpy(&entry->var, new_var, count);
 564         return count;
 565 }
 566
 567 static ssize_t
 568 efivar_show_raw(struct efivar_entry *entry, char *buf)
 569 {
 570         struct efi_variable *var = &entry->var;
 571         efi_status_t status;
 572
 573         if (!entry || !buf)
 574                 return 0;
 575
 576         status = get_var_data(entry->efivars, var);
 577         if (status != EFI_SUCCESS)
 578                 return -EIO;
 579
 580         memcpy(buf, var, sizeof(*var));
 581         return sizeof(*var);
 582 }
 583
 584 /*
 585  * Generic read/write functions that call the specific functions of
 586  * the attributes...
 587  */
 588 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 589                                 char *buf)
 590 {
 591         struct efivar_entry *var = to_efivar_entry(kobj);
 592         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 593         ssize_t ret = -EIO;
 594
 595         if (!capable(CAP_SYS_ADMIN))
 596                 return -EACCES;
 597
 598         if (efivar_attr->show) {
 599                 ret = efivar_attr->show(var, buf);
 600         }
 601         return ret;
 602 }
 603
 604 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 605                                 const char *buf, size_t count)
 606 {
 607         struct efivar_entry *var = to_efivar_entry(kobj);
 608         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 609         ssize_t ret = -EIO;
 610
 611         if (!capable(CAP_SYS_ADMIN))
 612                 return -EACCES;
 613
 614         if (efivar_attr->store)
 615                 ret = efivar_attr->store(var, buf, count);
 616
 617         return ret;
 618 }
 619
 620 static const struct sysfs_ops efivar_attr_ops = {
 621         .show = efivar_attr_show,
 622         .store = efivar_attr_store,
 623 };
 624
 625 static void efivar_release(struct kobject *kobj)
 626 {
 627         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 628         kfree(var);
 629 }
 630
 631 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 632 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 633 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 634 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 635 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 636
 637 static struct attribute *def_attrs[] = {
 638         &efivar_attr_guid.attr,
 639         &efivar_attr_size.attr,
 640         &efivar_attr_attributes.attr,
 641         &efivar_attr_data.attr,
 642         &efivar_attr_raw_var.attr,
 643         NULL,
 644 };
 645
 646 static struct kobj_type efivar_ktype = {
 647         .release = efivar_release,
 648         .sysfs_ops = &efivar_attr_ops,
 649         .default_attrs = def_attrs,
 650 };
 651
 652 static inline void
 653 efivar_unregister(struct efivar_entry *var)
 654 {
 655         kobject_put(&var->kobj);
 656 }
 657
 658 static int efivarfs_file_open(struct inode *inode, struct file *file)
 659 {
 660         file->private_data = inode->i_private;
 661         return 0;
 662 }
 663
 664 static int efi_status_to_err(efi_status_t status)
 665 {
 666         int err;
 667
 668         switch (status) {
 669         case EFI_INVALID_PARAMETER:
 670                 err = -EINVAL;
 671                 break;
 672         case EFI_OUT_OF_RESOURCES:
 673                 err = -ENOSPC;
 674                 break;
 675         case EFI_DEVICE_ERROR:
 676                 err = -EIO;
 677                 break;
 678         case EFI_WRITE_PROTECTED:
 679                 err = -EROFS;
 680                 break;
 681         case EFI_SECURITY_VIOLATION:
 682                 err = -EACCES;
 683                 break;
 684         case EFI_NOT_FOUND:
 685                 err = -EIO;
 686                 break;
 687         default:
 688                 err = -EINVAL;
 689         }
 690
 691         return err;
 692 }
 693
 694 static ssize_t efivarfs_file_write(struct file *file,
 695                 const char __user *userbuf, size_t count, loff_t *ppos)
 696 {
 697         struct efivar_entry *var = file->private_data;
 698         struct efivars *efivars;
 699         efi_status_t status;
 700         void *data;
 701         u32 attributes;
 702         struct inode *inode = file->f_mapping->host;
 703         unsigned long datasize = count - sizeof(attributes);
 704         unsigned long newdatasize;
 705         u64 storage_size, remaining_size, max_size;
 706         ssize_t bytes = 0;
 707
 708         if (count < sizeof(attributes))
 709                 return -EINVAL;
 710
 711         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 712                 return -EFAULT;
 713
 714         if (attributes & ~(EFI_VARIABLE_MASK))
 715                 return -EINVAL;
 716
 717         efivars = var->efivars;
 718
 719         /*
 720          * Ensure that the user can't allocate arbitrarily large
 721          * amounts of memory. Pick a default size of 64K if
 722          * QueryVariableInfo() isn't supported by the firmware.
 723          */
 724         spin_lock_irq(&efivars->lock);
 725
 726         if (!efivars->ops->query_variable_info)
 727                 status = EFI_UNSUPPORTED;
 728         else {
 729                 const struct efivar_operations *fops = efivars->ops;
 730                 status = fops->query_variable_info(attributes, &storage_size,
 731                                                    &remaining_size, &max_size);
 732         }
 733
 734         spin_unlock_irq(&efivars->lock);
 735
 736         if (status != EFI_SUCCESS) {
 737                 if (status != EFI_UNSUPPORTED)
 738                         return efi_status_to_err(status);
 739
 740                 remaining_size = 65536;
 741         }
 742
 743         if (datasize > remaining_size)
 744                 return -ENOSPC;
 745
 746         data = kmalloc(datasize, GFP_KERNEL);
 747         if (!data)
 748                 return -ENOMEM;
 749
 750         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 751                 bytes = -EFAULT;
 752                 goto out;
 753         }
 754
 755         if (validate_var(&var->var, data, datasize) == false) {
 756                 bytes = -EINVAL;
 757                 goto out;
 758         }
 759
 760         /*
 761          * The lock here protects the get_variable call, the conditional
 762          * set_variable call, and removal of the variable from the efivars
 763          * list (in the case of an authenticated delete).
 764          */
 765         spin_lock_irq(&efivars->lock);
 766
 767         status = efivars->ops->set_variable(var->var.VariableName,
 768                                             &var->var.VendorGuid,
 769                                             attributes, datasize,
 770                                             data);
 771
 772         if (status != EFI_SUCCESS) {
 773                 spin_unlock_irq(&efivars->lock);
 774                 kfree(data);
 775
 776                 return efi_status_to_err(status);
 777         }
 778
 779         bytes = count;
 780
 781         /*
 782          * Writing to the variable may have caused a change in size (which
 783          * could either be an append or an overwrite), or the variable to be
 784          * deleted. Perform a GetVariable() so we can tell what actually
 785          * happened.
 786          */
 787         newdatasize = 0;
 788         status = efivars->ops->get_variable(var->var.VariableName,
 789                                             &var->var.VendorGuid,
 790                                             NULL, &newdatasize,
 791                                             NULL);
 792
 793         if (status == EFI_BUFFER_TOO_SMALL) {
 794                 spin_unlock_irq(&efivars->lock);
 795                 mutex_lock(&inode->i_mutex);
 796                 i_size_write(inode, newdatasize + sizeof(attributes));
 797                 mutex_unlock(&inode->i_mutex);
 798
 799         } else if (status == EFI_NOT_FOUND) {
 800                 list_del(&var->list);
 801                 spin_unlock_irq(&efivars->lock);
 802                 efivar_unregister(var);
 803                 drop_nlink(inode);
 804                 d_delete(file->f_dentry);
 805                 dput(file->f_dentry);
 806
 807         } else {
 808                 spin_unlock_irq(&efivars->lock);
 809                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
 810                                 "status = %lx\n", status);
 811         }
 812
 813 out:
 814         kfree(data);
 815
 816         return bytes;
 817 }
 818
 819 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 820                 size_t count, loff_t *ppos)
 821 {
 822         struct efivar_entry *var = file->private_data;
 823         struct efivars *efivars = var->efivars;
 824         efi_status_t status;
 825         unsigned long datasize = 0;
 826         u32 attributes;
 827         void *data;
 828         ssize_t size = 0;
 829
 830         spin_lock_irq(&efivars->lock);
 831         status = efivars->ops->get_variable(var->var.VariableName,
 832                                             &var->var.VendorGuid,
 833                                             &attributes, &datasize, NULL);
 834         spin_unlock_irq(&efivars->lock);
 835
 836         if (status != EFI_BUFFER_TOO_SMALL)
 837                 return efi_status_to_err(status);
 838
 839         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 840
 841         if (!data)
 842                 return -ENOMEM;
 843
 844         spin_lock_irq(&efivars->lock);
 845         status = efivars->ops->get_variable(var->var.VariableName,
 846                                             &var->var.VendorGuid,
 847                                             &attributes, &datasize,
 848                                             (data + sizeof(attributes)));
 849         spin_unlock_irq(&efivars->lock);
 850
 851         if (status != EFI_SUCCESS) {
 852                 size = efi_status_to_err(status);
 853                 goto out_free;
 854         }
 855
 856         memcpy(data, &attributes, sizeof(attributes));
 857         size = simple_read_from_buffer(userbuf, count, ppos,
 858                                        data, datasize + sizeof(attributes));
 859 out_free:
 860         kfree(data);
 861
 862         return size;
 863 }
 864
 865 static void efivarfs_evict_inode(struct inode *inode)
 866 {
 867         clear_inode(inode);
 868 }
 869
 870 static const struct super_operations efivarfs_ops = {
 871         .statfs = simple_statfs,
 872         .drop_inode = generic_delete_inode,
 873         .evict_inode = efivarfs_evict_inode,
 874         .show_options = generic_show_options,
 875 };
 876
 877 static struct super_block *efivarfs_sb;
 878
 879 static const struct inode_operations efivarfs_dir_inode_operations;
 880
 881 static const struct file_operations efivarfs_file_operations = {
 882         .open   = efivarfs_file_open,
 883         .read   = efivarfs_file_read,
 884         .write  = efivarfs_file_write,
 885         .llseek = no_llseek,
 886 };
 887
 888 static struct inode *efivarfs_get_inode(struct super_block *sb,
 889                                 const struct inode *dir, int mode, dev_t dev)
 890 {
 891         struct inode *inode = new_inode(sb);
 892
 893         if (inode) {
 894                 inode->i_ino = get_next_ino();
 895                 inode->i_mode = mode;
 896                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 897                 switch (mode & S_IFMT) {
 898                 case S_IFREG:
 899                         inode->i_fop = &efivarfs_file_operations;
 900                         break;
 901                 case S_IFDIR:
 902                         inode->i_op = &efivarfs_dir_inode_operations;
 903                         inode->i_fop = &simple_dir_operations;
 904                         inc_nlink(inode);
 905                         break;
 906                 }
 907         }
 908         return inode;
 909 }
 910
 911 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
 912 {
 913         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
 914         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
 915         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
 916         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
 917         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
 918         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
 919         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
 920         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
 921         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
 922         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
 923         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
 924         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
 925         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
 926         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
 927         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
 928         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
 929 }
 930
 931 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 932                           umode_t mode, bool excl)
 933 {
 934         struct inode *inode;
 935         struct efivars *efivars = &__efivars;
 936         struct efivar_entry *var;
 937         int namelen, i = 0, err = 0;
 938
 939         /*
 940          * We need a GUID, plus at least one letter for the variable name,
 941          * plus the '-' separator
 942          */
 943         if (dentry->d_name.len < GUID_LEN + 2)
 944                 return -EINVAL;
 945
 946         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
 947         if (!inode)
 948                 return -ENOMEM;
 949
 950         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 951         if (!var) {
 952                 err = -ENOMEM;
 953                 goto out;
 954         }
 955
 956         /* length of the variable name itself: remove GUID and separator */
 957         namelen = dentry->d_name.len - GUID_LEN - 1;
 958
 959         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
 960                         &var->var.VendorGuid);
 961
 962         for (i = 0; i < namelen; i++)
 963                 var->var.VariableName[i] = dentry->d_name.name[i];
 964
 965         var->var.VariableName[i] = '\0';
 966
 967         inode->i_private = var;
 968         var->efivars = efivars;
 969         var->kobj.kset = efivars->kset;
 970
 971         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
 972                              dentry->d_name.name);
 973         if (err)
 974                 goto out;
 975
 976         kobject_uevent(&var->kobj, KOBJ_ADD);
 977         spin_lock_irq(&efivars->lock);
 978         list_add(&var->list, &efivars->list);
 979         spin_unlock_irq(&efivars->lock);
 980         d_instantiate(dentry, inode);
 981         dget(dentry);
 982 out:
 983         if (err) {
 984                 kfree(var);
 985                 iput(inode);
 986         }
 987         return err;
 988 }
 989
 990 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
 991 {
 992         struct efivar_entry *var = dentry->d_inode->i_private;
 993         struct efivars *efivars = var->efivars;
 994         efi_status_t status;
 995
 996         spin_lock_irq(&efivars->lock);
 997
 998         status = efivars->ops->set_variable(var->var.VariableName,
 999                                             &var->var.VendorGuid,
1000                                             0, 0, NULL);
1001
1002         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1003                 list_del(&var->list);
1004                 spin_unlock_irq(&efivars->lock);
1005                 efivar_unregister(var);
1006                 drop_nlink(dentry->d_inode);
1007                 dput(dentry);
1008                 return 0;
1009         }
1010
1011         spin_unlock_irq(&efivars->lock);
1012         return -EINVAL;
1013 };
1014
1015 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1016 {
1017         struct inode *inode = NULL;
1018         struct dentry *root;
1019         struct efivar_entry *entry, *n;
1020         struct efivars *efivars = &__efivars;
1021         char *name;
1022
1023         efivarfs_sb = sb;
1024
1025         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1026         sb->s_blocksize         = PAGE_CACHE_SIZE;
1027         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1028         sb->s_magic             = EFIVARFS_MAGIC;
1029         sb->s_op                = &efivarfs_ops;
1030         sb->s_time_gran         = 1;
1031
1032         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1033         if (!inode)
1034                 return -ENOMEM;
1035         inode->i_op = &efivarfs_dir_inode_operations;
1036
1037         root = d_make_root(inode);
1038         sb->s_root = root;
1039         if (!root)
1040                 return -ENOMEM;
1041
1042         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1043                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1044                 unsigned long size = 0;
1045                 int len, i;
1046
1047                 inode = NULL;
1048
1049                 len = utf16_strlen(entry->var.VariableName);
1050
1051                 /* name, plus '-', plus GUID, plus NUL*/
1052                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1053                 if (!name)
1054                         goto fail;
1055
1056                 for (i = 0; i < len; i++)
1057                         name[i] = entry->var.VariableName[i] & 0xFF;
1058
1059                 name[len] = '-';
1060
1061                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1062
1063                 name[len+GUID_LEN+1] = '\0';
1064
1065                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1066                                           S_IFREG | 0644, 0);
1067                 if (!inode)
1068                         goto fail_name;
1069
1070                 dentry = d_alloc_name(root, name);
1071                 if (!dentry)
1072                         goto fail_inode;
1073
1074                 /* copied by the above to local storage in the dentry. */
1075                 kfree(name);
1076
1077                 spin_lock_irq(&efivars->lock);
1078                 efivars->ops->get_variable(entry->var.VariableName,
1079                                            &entry->var.VendorGuid,
1080                                            &entry->var.Attributes,
1081                                            &size,
1082                                            NULL);
1083                 spin_unlock_irq(&efivars->lock);
1084
1085                 mutex_lock(&inode->i_mutex);
1086                 inode->i_private = entry;
1087                 i_size_write(inode, size+4);
1088                 mutex_unlock(&inode->i_mutex);
1089                 d_add(dentry, inode);
1090         }
1091
1092         return 0;
1093
1094 fail_inode:
1095         iput(inode);
1096 fail_name:
1097         kfree(name);
1098 fail:
1099         return -ENOMEM;
1100 }
1101
1102 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1103                                     int flags, const char *dev_name, void *data)
1104 {
1105         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1106 }
1107
1108 static void efivarfs_kill_sb(struct super_block *sb)
1109 {
1110         kill_litter_super(sb);
1111         efivarfs_sb = NULL;
1112 }
1113
1114 static struct file_system_type efivarfs_type = {
1115         .name    = "efivarfs",
1116         .mount   = efivarfs_mount,
1117         .kill_sb = efivarfs_kill_sb,
1118 };
1119
1120 static const struct inode_operations efivarfs_dir_inode_operations = {
1121         .lookup = simple_lookup,
1122         .unlink = efivarfs_unlink,
1123         .create = efivarfs_create,
1124 };
1125
1126 static struct pstore_info efi_pstore_info;
1127
1128 #ifdef CONFIG_PSTORE
1129
1130 static int efi_pstore_open(struct pstore_info *psi)
1131 {
1132         struct efivars *efivars = psi->data;
1133
1134         spin_lock_irq(&efivars->lock);
1135         efivars->walk_entry = list_first_entry(&efivars->list,
1136                                                struct efivar_entry, list);
1137         return 0;
1138 }
1139
1140 static int efi_pstore_close(struct pstore_info *psi)
1141 {
1142         struct efivars *efivars = psi->data;
1143
1144         spin_unlock_irq(&efivars->lock);
1145         return 0;
1146 }
1147
1148 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1149                                int *count, struct timespec *timespec,
1150                                char **buf, struct pstore_info *psi)
1151 {
1152         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1153         struct efivars *efivars = psi->data;
1154         char name[DUMP_NAME_LEN];
1155         int i;
1156         int cnt;
1157         unsigned int part, size;
1158         unsigned long time;
1159
1160         while (&efivars->walk_entry->list != &efivars->list) {
1161                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1162                                  vendor)) {
1163                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1164                                 name[i] = efivars->walk_entry->var.VariableName[i];
1165                         }
1166                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1167                                    type, &part, &cnt, &time) == 4) {
1168                                 *id = part;
1169                                 *count = cnt;
1170                                 timespec->tv_sec = time;
1171                                 timespec->tv_nsec = 0;
1172                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1173                                    type, &part, &time) == 3) {
1174                                 /*
1175                                  * Check if an old format,
1176                                  * which doesn't support holding
1177                                  * multiple logs, remains.
1178                                  */
1179                                 *id = part;
1180                                 *count = 0;
1181                                 timespec->tv_sec = time;
1182                                 timespec->tv_nsec = 0;
1183                         } else {
1184                                 efivars->walk_entry = list_entry(
1185                                                 efivars->walk_entry->list.next,
1186                                                 struct efivar_entry, list);
1187                                 continue;
1188                         }
1189
1190                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1191                         size = efivars->walk_entry->var.DataSize;
1192                         *buf = kmalloc(size, GFP_KERNEL);
1193                         if (*buf == NULL)
1194                                 return -ENOMEM;
1195                         memcpy(*buf, efivars->walk_entry->var.Data,
1196                                size);
1197                         efivars->walk_entry = list_entry(
1198                                         efivars->walk_entry->list.next,
1199                                         struct efivar_entry, list);
1200                         return size;
1201                 }
1202                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1203                                                  struct efivar_entry, list);
1204         }
1205         return 0;
1206 }
1207
1208 static int efi_pstore_write(enum pstore_type_id type,
1209                 enum kmsg_dump_reason reason, u64 *id,
1210                 unsigned int part, int count, size_t size,
1211                 struct pstore_info *psi)
1212 {
1213         char name[DUMP_NAME_LEN];
1214         efi_char16_t efi_name[DUMP_NAME_LEN];
1215         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1216         struct efivars *efivars = psi->data;
1217         int i, ret = 0;
1218         u64 storage_space, remaining_space, max_variable_size;
1219         efi_status_t status = EFI_NOT_FOUND;
1220         unsigned long flags;
1221
1222         if (pstore_cannot_block_path(reason)) {
1223                 /*
1224                  * If the lock is taken by another cpu in non-blocking path,
1225                  * this driver returns without entering firmware to avoid
1226                  * hanging up.
1227                  */
1228                 if (!spin_trylock_irqsave(&efivars->lock, flags))
1229                         return -EBUSY;
1230         } else
1231                 spin_lock_irqsave(&efivars->lock, flags);
1232
1233         /*
1234          * Check if there is a space enough to log.
1235          * size: a size of logging data
1236          * DUMP_NAME_LEN * 2: a maximum size of variable name
1237          */
1238         status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
1239                                                    &storage_space,
1240                                                    &remaining_space,
1241                                                    &max_variable_size);
1242         if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
1243                 spin_unlock_irqrestore(&efivars->lock, flags);
1244                 *id = part;
1245                 return -ENOSPC;
1246         }
1247
1248         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1249                 get_seconds());
1250
1251         for (i = 0; i < DUMP_NAME_LEN; i++)
1252                 efi_name[i] = name[i];
1253
1254         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1255                                    size, psi->buf);
1256
1257         spin_unlock_irqrestore(&efivars->lock, flags);
1258
1259         if (reason == KMSG_DUMP_OOPS)
1260                 schedule_work(&efivar_work);
1261
1262         *id = part;
1263         return ret;
1264 };
1265
1266 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1267                             struct timespec time, struct pstore_info *psi)
1268 {
1269         char name[DUMP_NAME_LEN];
1270         efi_char16_t efi_name[DUMP_NAME_LEN];
1271         char name_old[DUMP_NAME_LEN];
1272         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1273         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1274         struct efivars *efivars = psi->data;
1275         struct efivar_entry *entry, *found = NULL;
1276         int i;
1277
1278         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1279                 time.tv_sec);
1280
1281         spin_lock_irq(&efivars->lock);
1282
1283         for (i = 0; i < DUMP_NAME_LEN; i++)
1284                 efi_name[i] = name[i];
1285
1286         /*
1287          * Clean up an entry with the same name
1288          */
1289
1290         list_for_each_entry(entry, &efivars->list, list) {
1291                 get_var_data_locked(efivars, &entry->var);
1292
1293                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1294                         continue;
1295                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1296                                   utf16_strlen(efi_name))) {
1297                         /*
1298                          * Check if an old format,
1299                          * which doesn't support holding
1300                          * multiple logs, remains.
1301                          */
1302                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1303                                 (unsigned int)id, time.tv_sec);
1304
1305                         for (i = 0; i < DUMP_NAME_LEN; i++)
1306                                 efi_name_old[i] = name_old[i];
1307
1308                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1309                                           utf16_strlen(efi_name_old)))
1310                                 continue;
1311                 }
1312
1313                 /* found */
1314                 found = entry;
1315                 efivars->ops->set_variable(entry->var.VariableName,
1316                                            &entry->var.VendorGuid,
1317                                            PSTORE_EFI_ATTRIBUTES,
1318                                            0, NULL);
1319                 break;
1320         }
1321
1322         if (found)
1323                 list_del(&found->list);
1324
1325         spin_unlock_irq(&efivars->lock);
1326
1327         if (found)
1328                 efivar_unregister(found);
1329
1330         return 0;
1331 }
1332 #else
1333 static int efi_pstore_open(struct pstore_info *psi)
1334 {
1335         return 0;
1336 }
1337
1338 static int efi_pstore_close(struct pstore_info *psi)
1339 {
1340         return 0;
1341 }
1342
1343 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1344                                struct timespec *timespec,
1345                                char **buf, struct pstore_info *psi)
1346 {
1347         return -1;
1348 }
1349
1350 static int efi_pstore_write(enum pstore_type_id type,
1351                 enum kmsg_dump_reason reason, u64 *id,
1352                 unsigned int part, int count, size_t size,
1353                 struct pstore_info *psi)
1354 {
1355         return 0;
1356 }
1357
1358 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1359                             struct timespec time, struct pstore_info *psi)
1360 {
1361         return 0;
1362 }
1363 #endif
1364
1365 static struct pstore_info efi_pstore_info = {
1366         .owner          = THIS_MODULE,
1367         .name           = "efi",
1368         .open           = efi_pstore_open,
1369         .close          = efi_pstore_close,
1370         .read           = efi_pstore_read,
1371         .write          = efi_pstore_write,
1372         .erase          = efi_pstore_erase,
1373 };
1374
1375 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1376                              struct bin_attribute *bin_attr,
1377                              char *buf, loff_t pos, size_t count)
1378 {
1379         struct efi_variable *new_var = (struct efi_variable *)buf;
1380         struct efivars *efivars = bin_attr->private;
1381         struct efivar_entry *search_efivar, *n;
1382         unsigned long strsize1, strsize2;
1383         efi_status_t status = EFI_NOT_FOUND;
1384         int found = 0;
1385
1386         if (!capable(CAP_SYS_ADMIN))
1387                 return -EACCES;
1388
1389         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1390             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1391                 printk(KERN_ERR "efivars: Malformed variable content\n");
1392                 return -EINVAL;
1393         }
1394
1395         spin_lock_irq(&efivars->lock);
1396
1397         /*
1398          * Does this variable already exist?
1399          */
1400         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1401                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1402                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1403                 if (strsize1 == strsize2 &&
1404                         !memcmp(&(search_efivar->var.VariableName),
1405                                 new_var->VariableName, strsize1) &&
1406                         !efi_guidcmp(search_efivar->var.VendorGuid,
1407                                 new_var->VendorGuid)) {
1408                         found = 1;
1409                         break;
1410                 }
1411         }
1412         if (found) {
1413                 spin_unlock_irq(&efivars->lock);
1414                 return -EINVAL;
1415         }
1416
1417         /* now *really* create the variable via EFI */
1418         status = efivars->ops->set_variable(new_var->VariableName,
1419                                             &new_var->VendorGuid,
1420                                             new_var->Attributes,
1421                                             new_var->DataSize,
1422                                             new_var->Data);
1423
1424         if (status != EFI_SUCCESS) {
1425                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1426                         status);
1427                 spin_unlock_irq(&efivars->lock);
1428                 return -EIO;
1429         }
1430         spin_unlock_irq(&efivars->lock);
1431
1432         /* Create the entry in sysfs.  Locking is not required here */
1433         status = efivar_create_sysfs_entry(efivars,
1434                                            utf16_strsize(new_var->VariableName,
1435                                                          1024),
1436                                            new_var->VariableName,
1437                                            &new_var->VendorGuid);
1438         if (status) {
1439                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1440         }
1441         return count;
1442 }
1443
1444 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1445                              struct bin_attribute *bin_attr,
1446                              char *buf, loff_t pos, size_t count)
1447 {
1448         struct efi_variable *del_var = (struct efi_variable *)buf;
1449         struct efivars *efivars = bin_attr->private;
1450         struct efivar_entry *search_efivar, *n;
1451         unsigned long strsize1, strsize2;
1452         efi_status_t status = EFI_NOT_FOUND;
1453         int found = 0;
1454
1455         if (!capable(CAP_SYS_ADMIN))
1456                 return -EACCES;
1457
1458         spin_lock_irq(&efivars->lock);
1459
1460         /*
1461          * Does this variable already exist?
1462          */
1463         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1464                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1465                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1466                 if (strsize1 == strsize2 &&
1467                         !memcmp(&(search_efivar->var.VariableName),
1468                                 del_var->VariableName, strsize1) &&
1469                         !efi_guidcmp(search_efivar->var.VendorGuid,
1470                                 del_var->VendorGuid)) {
1471                         found = 1;
1472                         break;
1473                 }
1474         }
1475         if (!found) {
1476                 spin_unlock_irq(&efivars->lock);
1477                 return -EINVAL;
1478         }
1479         /* force the Attributes/DataSize to 0 to ensure deletion */
1480         del_var->Attributes = 0;
1481         del_var->DataSize = 0;
1482
1483         status = efivars->ops->set_variable(del_var->VariableName,
1484                                             &del_var->VendorGuid,
1485                                             del_var->Attributes,
1486                                             del_var->DataSize,
1487                                             del_var->Data);
1488
1489         if (status != EFI_SUCCESS) {
1490                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1491                         status);
1492                 spin_unlock_irq(&efivars->lock);
1493                 return -EIO;
1494         }
1495         list_del(&search_efivar->list);
1496         /* We need to release this lock before unregistering. */
1497         spin_unlock_irq(&efivars->lock);
1498         efivar_unregister(search_efivar);
1499
1500         /* It's dead Jim.... */
1501         return count;
1502 }
1503
1504 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1505 {
1506         struct efivar_entry *entry, *n;
1507         struct efivars *efivars = &__efivars;
1508         unsigned long strsize1, strsize2;
1509         bool found = false;
1510
1511         strsize1 = utf16_strsize(variable_name, 1024);
1512         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1513                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1514                 if (strsize1 == strsize2 &&
1515                         !memcmp(variable_name, &(entry->var.VariableName),
1516                                 strsize2) &&
1517                         !efi_guidcmp(entry->var.VendorGuid,
1518                                 *vendor)) {
1519                         found = true;
1520                         break;
1521                 }
1522         }
1523         return found;
1524 }
1525
1526 static void efivar_update_sysfs_entries(struct work_struct *work)
1527 {
1528         struct efivars *efivars = &__efivars;
1529         efi_guid_t vendor;
1530         efi_char16_t *variable_name;
1531         unsigned long variable_name_size = 1024;
1532         efi_status_t status = EFI_NOT_FOUND;
1533         bool found;
1534
1535         /* Add new sysfs entries */
1536         while (1) {
1537                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1538                 if (!variable_name) {
1539                         pr_err("efivars: Memory allocation failed.\n");
1540                         return;
1541                 }
1542
1543                 spin_lock_irq(&efivars->lock);
1544                 found = false;
1545                 while (1) {
1546                         variable_name_size = 1024;
1547                         status = efivars->ops->get_next_variable(
1548                                                         &variable_name_size,
1549                                                         variable_name,
1550                                                         &vendor);
1551                         if (status != EFI_SUCCESS) {
1552                                 break;
1553                         } else {
1554                                 if (!variable_is_present(variable_name,
1555                                     &vendor)) {
1556                                         found = true;
1557                                         break;
1558                                 }
1559                         }
1560                 }
1561                 spin_unlock_irq(&efivars->lock);
1562
1563                 if (!found) {
1564                         kfree(variable_name);
1565                         break;
1566                 } else
1567                         efivar_create_sysfs_entry(efivars,
1568                                                   variable_name_size,
1569                                                   variable_name, &vendor);
1570         }
1571 }
1572
1573 /*
1574  * Let's not leave out systab information that snuck into
1575  * the efivars driver
1576  */
1577 static ssize_t systab_show(struct kobject *kobj,
1578                            struct kobj_attribute *attr, char *buf)
1579 {
1580         char *str = buf;
1581
1582         if (!kobj || !buf)
1583                 return -EINVAL;
1584
1585         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1586                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1587         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1588                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1589         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1590                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1591         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1592                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1593         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1594                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1595         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1596                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1597         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1598                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1599
1600         return str - buf;
1601 }
1602
1603 static struct kobj_attribute efi_attr_systab =
1604                         __ATTR(systab, 0400, systab_show, NULL);
1605
1606 static struct attribute *efi_subsys_attrs[] = {
1607         &efi_attr_systab.attr,
1608         NULL,   /* maybe more in the future? */
1609 };
1610
1611 static struct attribute_group efi_subsys_attr_group = {
1612         .attrs = efi_subsys_attrs,
1613 };
1614
1615 static struct kobject *efi_kobj;
1616
1617 /*
1618  * efivar_create_sysfs_entry()
1619  * Requires:
1620  *    variable_name_size = number of bytes required to hold
1621  *                         variable_name (not counting the NULL
1622  *                         character at the end.
1623  *    efivars->lock is not held on entry or exit.
1624  * Returns 1 on failure, 0 on success
1625  */
1626 static int
1627 efivar_create_sysfs_entry(struct efivars *efivars,
1628                           unsigned long variable_name_size,
1629                           efi_char16_t *variable_name,
1630                           efi_guid_t *vendor_guid)
1631 {
1632         int i, short_name_size;
1633         char *short_name;
1634         struct efivar_entry *new_efivar;
1635
1636         /*
1637          * Length of the variable bytes in ASCII, plus the '-' separator,
1638          * plus the GUID, plus trailing NUL
1639          */
1640         short_name_size = variable_name_size / sizeof(efi_char16_t)
1641                                 + 1 + GUID_LEN + 1;
1642
1643         short_name = kzalloc(short_name_size, GFP_KERNEL);
1644         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1645
1646         if (!short_name || !new_efivar)  {
1647                 kfree(short_name);
1648                 kfree(new_efivar);
1649                 return 1;
1650         }
1651
1652         new_efivar->efivars = efivars;
1653         memcpy(new_efivar->var.VariableName, variable_name,
1654                 variable_name_size);
1655         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1656
1657         /* Convert Unicode to normal chars (assume top bits are 0),
1658            ala UTF-8 */
1659         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1660                 short_name[i] = variable_name[i] & 0xFF;
1661         }
1662         /* This is ugly, but necessary to separate one vendor's
1663            private variables from another's.         */
1664
1665         *(short_name + strlen(short_name)) = '-';
1666         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1667
1668         new_efivar->kobj.kset = efivars->kset;
1669         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1670                                  "%s", short_name);
1671         if (i) {
1672                 kfree(short_name);
1673                 kfree(new_efivar);
1674                 return 1;
1675         }
1676
1677         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1678         kfree(short_name);
1679         short_name = NULL;
1680
1681         spin_lock_irq(&efivars->lock);
1682         list_add(&new_efivar->list, &efivars->list);
1683         spin_unlock_irq(&efivars->lock);
1684
1685         return 0;
1686 }
1687
1688 static int
1689 create_efivars_bin_attributes(struct efivars *efivars)
1690 {
1691         struct bin_attribute *attr;
1692         int error;
1693
1694         /* new_var */
1695         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1696         if (!attr)
1697                 return -ENOMEM;
1698
1699         attr->attr.name = "new_var";
1700         attr->attr.mode = 0200;
1701         attr->write = efivar_create;
1702         attr->private = efivars;
1703         efivars->new_var = attr;
1704
1705         /* del_var */
1706         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1707         if (!attr) {
1708                 error = -ENOMEM;
1709                 goto out_free;
1710         }
1711         attr->attr.name = "del_var";
1712         attr->attr.mode = 0200;
1713         attr->write = efivar_delete;
1714         attr->private = efivars;
1715         efivars->del_var = attr;
1716
1717         sysfs_bin_attr_init(efivars->new_var);
1718         sysfs_bin_attr_init(efivars->del_var);
1719
1720         /* Register */
1721         error = sysfs_create_bin_file(&efivars->kset->kobj,
1722                                       efivars->new_var);
1723         if (error) {
1724                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1725                         " due to error %d\n", error);
1726                 goto out_free;
1727         }
1728         error = sysfs_create_bin_file(&efivars->kset->kobj,
1729                                       efivars->del_var);
1730         if (error) {
1731                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1732                         " due to error %d\n", error);
1733                 sysfs_remove_bin_file(&efivars->kset->kobj,
1734                                       efivars->new_var);
1735                 goto out_free;
1736         }
1737
1738         return 0;
1739 out_free:
1740         kfree(efivars->del_var);
1741         efivars->del_var = NULL;
1742         kfree(efivars->new_var);
1743         efivars->new_var = NULL;
1744         return error;
1745 }
1746
1747 void unregister_efivars(struct efivars *efivars)
1748 {
1749         struct efivar_entry *entry, *n;
1750
1751         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1752                 spin_lock_irq(&efivars->lock);
1753                 list_del(&entry->list);
1754                 spin_unlock_irq(&efivars->lock);
1755                 efivar_unregister(entry);
1756         }
1757         if (efivars->new_var)
1758                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1759         if (efivars->del_var)
1760                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1761         kfree(efivars->new_var);
1762         kfree(efivars->del_var);
1763         kobject_put(efivars->kobject);
1764         kset_unregister(efivars->kset);
1765 }
1766 EXPORT_SYMBOL_GPL(unregister_efivars);
1767
1768 int register_efivars(struct efivars *efivars,
1769                      const struct efivar_operations *ops,
1770                      struct kobject *parent_kobj)
1771 {
1772         efi_status_t status = EFI_NOT_FOUND;
1773         efi_guid_t vendor_guid;
1774         efi_char16_t *variable_name;
1775         unsigned long variable_name_size = 1024;
1776         int error = 0;
1777
1778         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1779         if (!variable_name) {
1780                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1781                 return -ENOMEM;
1782         }
1783
1784         spin_lock_init(&efivars->lock);
1785         INIT_LIST_HEAD(&efivars->list);
1786         efivars->ops = ops;
1787
1788         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1789         if (!efivars->kset) {
1790                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1791                 error = -ENOMEM;
1792                 goto out;
1793         }
1794
1795         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1796         if (!efivars->kobject) {
1797                 pr_err("efivars: Subsystem registration failed.\n");
1798                 error = -ENOMEM;
1799                 kset_unregister(efivars->kset);
1800                 goto out;
1801         }
1802
1803         /*
1804          * Per EFI spec, the maximum storage allocated for both
1805          * the variable name and variable data is 1024 bytes.
1806          */
1807
1808         do {
1809                 variable_name_size = 1024;
1810
1811                 status = ops->get_next_variable(&variable_name_size,
1812                                                 variable_name,
1813                                                 &vendor_guid);
1814                 switch (status) {
1815                 case EFI_SUCCESS:
1816                         efivar_create_sysfs_entry(efivars,
1817                                                   variable_name_size,
1818                                                   variable_name,
1819                                                   &vendor_guid);
1820                         break;
1821                 case EFI_NOT_FOUND:
1822                         break;
1823                 default:
1824                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1825                                 status);
1826                         status = EFI_NOT_FOUND;
1827                         break;
1828                 }
1829         } while (status != EFI_NOT_FOUND);
1830
1831         error = create_efivars_bin_attributes(efivars);
1832         if (error)
1833                 unregister_efivars(efivars);
1834
1835         efivars->efi_pstore_info = efi_pstore_info;
1836
1837         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1838         if (efivars->efi_pstore_info.buf) {
1839                 efivars->efi_pstore_info.bufsize = 1024;
1840                 efivars->efi_pstore_info.data = efivars;
1841                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1842                 pstore_register(&efivars->efi_pstore_info);
1843         }
1844
1845         register_filesystem(&efivarfs_type);
1846
1847 out:
1848         kfree(variable_name);
1849
1850         return error;
1851 }
1852 EXPORT_SYMBOL_GPL(register_efivars);
1853
1854 /*
1855  * For now we register the efi subsystem with the firmware subsystem
1856  * and the vars subsystem with the efi subsystem.  In the future, it
1857  * might make sense to split off the efi subsystem into its own
1858  * driver, but for now only efivars will register with it, so just
1859  * include it here.
1860  */
1861
1862 static int __init
1863 efivars_init(void)
1864 {
1865         int error = 0;
1866
1867         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1868                EFIVARS_DATE);
1869
1870         if (!efi_enabled(EFI_RUNTIME_SERVICES))
1871                 return 0;
1872
1873         /* For now we'll register the efi directory at /sys/firmware/efi */
1874         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1875         if (!efi_kobj) {
1876                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1877                 return -ENOMEM;
1878         }
1879
1880         ops.get_variable = efi.get_variable;
1881         ops.set_variable = efi.set_variable;
1882         ops.get_next_variable = efi.get_next_variable;
1883         ops.query_variable_info = efi.query_variable_info;
1884
1885         error = register_efivars(&__efivars, &ops, efi_kobj);
1886         if (error)
1887                 goto err_put;
1888
1889         /* Don't forget the systab entry */
1890         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1891         if (error) {
1892                 printk(KERN_ERR
1893                        "efivars: Sysfs attribute export failed with error %d.\n",
1894                        error);
1895                 goto err_unregister;
1896         }
1897
1898         return 0;
1899
1900 err_unregister:
1901         unregister_efivars(&__efivars);
1902 err_put:
1903         kobject_put(efi_kobj);
1904         return error;
1905 }
1906
1907 static void __exit
1908 efivars_exit(void)
1909 {
1910         cancel_work_sync(&efivar_work);
1911
1912         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1913                 unregister_efivars(&__efivars);
1914                 kobject_put(efi_kobj);
1915         }
1916 }
1917
1918 module_init(efivars_init);
1919 module_exit(efivars_exit);
1920