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