linux/drivers/firmware/efivars.c
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   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#include <linux/ctype.h>
  83#include <linux/ucs2_string.h>
  84
  85#include <linux/fs.h>
  86#include <linux/ramfs.h>
  87#include <linux/pagemap.h>
  88
  89#include <asm/uaccess.h>
  90
  91#define EFIVARS_VERSION "0.08"
  92#define EFIVARS_DATE "2004-May-17"
  93
  94MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  95MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  96MODULE_LICENSE("GPL");
  97MODULE_VERSION(EFIVARS_VERSION);
  98
  99#define DUMP_NAME_LEN 52
 100
 101/*
 102 * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
 103 * not including trailing NUL
 104 */
 105#define GUID_LEN 36
 106
 107static bool efivars_pstore_disable =
 108        IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
 109
 110module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
 111
 112/*
 113 * The maximum size of VariableName + Data = 1024
 114 * Therefore, it's reasonable to save that much
 115 * space in each part of the structure,
 116 * and we use a page for reading/writing.
 117 */
 118
 119struct efi_variable {
 120        efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 121        efi_guid_t    VendorGuid;
 122        unsigned long DataSize;
 123        __u8          Data[1024];
 124        efi_status_t  Status;
 125        __u32         Attributes;
 126} __attribute__((packed));
 127
 128struct efivar_entry {
 129        struct efivars *efivars;
 130        struct efi_variable var;
 131        struct list_head list;
 132        struct kobject kobj;
 133};
 134
 135struct efivar_attribute {
 136        struct attribute attr;
 137        ssize_t (*show) (struct efivar_entry *entry, char *buf);
 138        ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 139};
 140
 141static struct efivars __efivars;
 142static struct efivar_operations ops;
 143
 144#define PSTORE_EFI_ATTRIBUTES \
 145        (EFI_VARIABLE_NON_VOLATILE | \
 146         EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 147         EFI_VARIABLE_RUNTIME_ACCESS)
 148
 149#define EFIVAR_ATTR(_name, _mode, _show, _store) \
 150struct efivar_attribute efivar_attr_##_name = { \
 151        .attr = {.name = __stringify(_name), .mode = _mode}, \
 152        .show = _show, \
 153        .store = _store, \
 154};
 155
 156#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 157#define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 158
 159/*
 160 * Prototype for sysfs creation function
 161 */
 162static int
 163efivar_create_sysfs_entry(struct efivars *efivars,
 164                          unsigned long variable_name_size,
 165                          efi_char16_t *variable_name,
 166                          efi_guid_t *vendor_guid);
 167
 168/*
 169 * Prototype for workqueue functions updating sysfs entry
 170 */
 171
 172static void efivar_update_sysfs_entries(struct work_struct *);
 173static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
 174static bool efivar_wq_enabled = true;
 175
 176static bool
 177validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 178                     unsigned long len)
 179{
 180        struct efi_generic_dev_path *node;
 181        int offset = 0;
 182
 183        node = (struct efi_generic_dev_path *)buffer;
 184
 185        if (len < sizeof(*node))
 186                return false;
 187
 188        while (offset <= len - sizeof(*node) &&
 189               node->length >= sizeof(*node) &&
 190                node->length <= len - offset) {
 191                offset += node->length;
 192
 193                if ((node->type == EFI_DEV_END_PATH ||
 194                     node->type == EFI_DEV_END_PATH2) &&
 195                    node->sub_type == EFI_DEV_END_ENTIRE)
 196                        return true;
 197
 198                node = (struct efi_generic_dev_path *)(buffer + offset);
 199        }
 200
 201        /*
 202         * If we're here then either node->length pointed past the end
 203         * of the buffer or we reached the end of the buffer without
 204         * finding a device path end node.
 205         */
 206        return false;
 207}
 208
 209static bool
 210validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 211                    unsigned long len)
 212{
 213        /* An array of 16-bit integers */
 214        if ((len % 2) != 0)
 215                return false;
 216
 217        return true;
 218}
 219
 220static bool
 221validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 222                     unsigned long len)
 223{
 224        u16 filepathlength;
 225        int i, desclength = 0, namelen;
 226
 227        namelen = ucs2_strnlen(var->VariableName, sizeof(var->VariableName));
 228
 229        /* Either "Boot" or "Driver" followed by four digits of hex */
 230        for (i = match; i < match+4; i++) {
 231                if (var->VariableName[i] > 127 ||
 232                    hex_to_bin(var->VariableName[i] & 0xff) < 0)
 233                        return true;
 234        }
 235
 236        /* Reject it if there's 4 digits of hex and then further content */
 237        if (namelen > match + 4)
 238                return false;
 239
 240        /* A valid entry must be at least 8 bytes */
 241        if (len < 8)
 242                return false;
 243
 244        filepathlength = buffer[4] | buffer[5] << 8;
 245
 246        /*
 247         * There's no stored length for the description, so it has to be
 248         * found by hand
 249         */
 250        desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 251
 252        /* Each boot entry must have a descriptor */
 253        if (!desclength)
 254                return false;
 255
 256        /*
 257         * If the sum of the length of the description, the claimed filepath
 258         * length and the original header are greater than the length of the
 259         * variable, it's malformed
 260         */
 261        if ((desclength + filepathlength + 6) > len)
 262                return false;
 263
 264        /*
 265         * And, finally, check the filepath
 266         */
 267        return validate_device_path(var, match, buffer + desclength + 6,
 268                                    filepathlength);
 269}
 270
 271static bool
 272validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 273                unsigned long len)
 274{
 275        /* A single 16-bit integer */
 276        if (len != 2)
 277                return false;
 278
 279        return true;
 280}
 281
 282static bool
 283validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 284                      unsigned long len)
 285{
 286        int i;
 287
 288        for (i = 0; i < len; i++) {
 289                if (buffer[i] > 127)
 290                        return false;
 291
 292                if (buffer[i] == 0)
 293                        return true;
 294        }
 295
 296        return false;
 297}
 298
 299struct variable_validate {
 300        char *name;
 301        bool (*validate)(struct efi_variable *var, int match, u8 *data,
 302                         unsigned long len);
 303};
 304
 305static const struct variable_validate variable_validate[] = {
 306        { "BootNext", validate_uint16 },
 307        { "BootOrder", validate_boot_order },
 308        { "DriverOrder", validate_boot_order },
 309        { "Boot*", validate_load_option },
 310        { "Driver*", validate_load_option },
 311        { "ConIn", validate_device_path },
 312        { "ConInDev", validate_device_path },
 313        { "ConOut", validate_device_path },
 314        { "ConOutDev", validate_device_path },
 315        { "ErrOut", validate_device_path },
 316        { "ErrOutDev", validate_device_path },
 317        { "Timeout", validate_uint16 },
 318        { "Lang", validate_ascii_string },
 319        { "PlatformLang", validate_ascii_string },
 320        { "", NULL },
 321};
 322
 323static bool
 324validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 325{
 326        int i;
 327        u16 *unicode_name = var->VariableName;
 328
 329        for (i = 0; variable_validate[i].validate != NULL; i++) {
 330                const char *name = variable_validate[i].name;
 331                int match;
 332
 333                for (match = 0; ; match++) {
 334                        char c = name[match];
 335                        u16 u = unicode_name[match];
 336
 337                        /* All special variables are plain ascii */
 338                        if (u > 127)
 339                                return true;
 340
 341                        /* Wildcard in the matching name means we've matched */
 342                        if (c == '*')
 343                                return variable_validate[i].validate(var,
 344                                                             match, data, len);
 345
 346                        /* Case sensitive match */
 347                        if (c != u)
 348                                break;
 349
 350                        /* Reached the end of the string while matching */
 351                        if (!c)
 352                                return variable_validate[i].validate(var,
 353                                                             match, data, len);
 354                }
 355        }
 356
 357        return true;
 358}
 359
 360static efi_status_t
 361get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 362{
 363        efi_status_t status;
 364
 365        var->DataSize = 1024;
 366        status = efivars->ops->get_variable(var->VariableName,
 367                                            &var->VendorGuid,
 368                                            &var->Attributes,
 369                                            &var->DataSize,
 370                                            var->Data);
 371        return status;
 372}
 373
 374static efi_status_t
 375get_var_data(struct efivars *efivars, struct efi_variable *var)
 376{
 377        efi_status_t status;
 378        unsigned long flags;
 379
 380        spin_lock_irqsave(&efivars->lock, flags);
 381        status = get_var_data_locked(efivars, var);
 382        spin_unlock_irqrestore(&efivars->lock, flags);
 383
 384        if (status != EFI_SUCCESS) {
 385                printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 386                        status);
 387        }
 388        return status;
 389}
 390
 391static efi_status_t
 392check_var_size_locked(struct efivars *efivars, u32 attributes,
 393                        unsigned long size)
 394{
 395        const struct efivar_operations *fops = efivars->ops;
 396
 397        if (!efivars->ops->query_variable_store)
 398                return EFI_UNSUPPORTED;
 399
 400        return fops->query_variable_store(attributes, size);
 401}
 402
 403
 404static efi_status_t
 405check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
 406{
 407        efi_status_t status;
 408        unsigned long flags;
 409
 410        spin_lock_irqsave(&efivars->lock, flags);
 411        status = check_var_size_locked(efivars, attributes, size);
 412        spin_unlock_irqrestore(&efivars->lock, flags);
 413
 414        return status;
 415}
 416
 417static ssize_t
 418efivar_guid_read(struct efivar_entry *entry, char *buf)
 419{
 420        struct efi_variable *var = &entry->var;
 421        char *str = buf;
 422
 423        if (!entry || !buf)
 424                return 0;
 425
 426        efi_guid_unparse(&var->VendorGuid, str);
 427        str += strlen(str);
 428        str += sprintf(str, "\n");
 429
 430        return str - buf;
 431}
 432
 433static ssize_t
 434efivar_attr_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        if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
 448                str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 449        if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 450                str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 451        if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 452                str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 453        if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 454                str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 455        if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 456                str += sprintf(str,
 457                        "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 458        if (var->Attributes &
 459                        EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 460                str += sprintf(str,
 461                        "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 462        if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 463                str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 464        return str - buf;
 465}
 466
 467static ssize_t
 468efivar_size_read(struct efivar_entry *entry, char *buf)
 469{
 470        struct efi_variable *var = &entry->var;
 471        char *str = buf;
 472        efi_status_t status;
 473
 474        if (!entry || !buf)
 475                return -EINVAL;
 476
 477        status = get_var_data(entry->efivars, var);
 478        if (status != EFI_SUCCESS)
 479                return -EIO;
 480
 481        str += sprintf(str, "0x%lx\n", var->DataSize);
 482        return str - buf;
 483}
 484
 485static ssize_t
 486efivar_data_read(struct efivar_entry *entry, char *buf)
 487{
 488        struct efi_variable *var = &entry->var;
 489        efi_status_t status;
 490
 491        if (!entry || !buf)
 492                return -EINVAL;
 493
 494        status = get_var_data(entry->efivars, var);
 495        if (status != EFI_SUCCESS)
 496                return -EIO;
 497
 498        memcpy(buf, var->Data, var->DataSize);
 499        return var->DataSize;
 500}
 501/*
 502 * We allow each variable to be edited via rewriting the
 503 * entire efi variable structure.
 504 */
 505static ssize_t
 506efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 507{
 508        struct efi_variable *new_var, *var = &entry->var;
 509        struct efivars *efivars = entry->efivars;
 510        efi_status_t status = EFI_NOT_FOUND;
 511
 512        if (count != sizeof(struct efi_variable))
 513                return -EINVAL;
 514
 515        new_var = (struct efi_variable *)buf;
 516        /*
 517         * If only updating the variable data, then the name
 518         * and guid should remain the same
 519         */
 520        if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 521                efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 522                printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 523                return -EINVAL;
 524        }
 525
 526        if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 527                printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 528                return -EINVAL;
 529        }
 530
 531        if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 532            validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 533                printk(KERN_ERR "efivars: Malformed variable content\n");
 534                return -EINVAL;
 535        }
 536
 537        spin_lock_irq(&efivars->lock);
 538
 539        status = check_var_size_locked(efivars, new_var->Attributes,
 540               new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
 541
 542        if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
 543                status = efivars->ops->set_variable(new_var->VariableName,
 544                                                    &new_var->VendorGuid,
 545                                                    new_var->Attributes,
 546                                                    new_var->DataSize,
 547                                                    new_var->Data);
 548
 549        spin_unlock_irq(&efivars->lock);
 550
 551        if (status != EFI_SUCCESS) {
 552                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 553                        status);
 554                return -EIO;
 555        }
 556
 557        memcpy(&entry->var, new_var, count);
 558        return count;
 559}
 560
 561static ssize_t
 562efivar_show_raw(struct efivar_entry *entry, char *buf)
 563{
 564        struct efi_variable *var = &entry->var;
 565        efi_status_t status;
 566
 567        if (!entry || !buf)
 568                return 0;
 569
 570        status = get_var_data(entry->efivars, var);
 571        if (status != EFI_SUCCESS)
 572                return -EIO;
 573
 574        memcpy(buf, var, sizeof(*var));
 575        return sizeof(*var);
 576}
 577
 578/*
 579 * Generic read/write functions that call the specific functions of
 580 * the attributes...
 581 */
 582static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 583                                char *buf)
 584{
 585        struct efivar_entry *var = to_efivar_entry(kobj);
 586        struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 587        ssize_t ret = -EIO;
 588
 589        if (!capable(CAP_SYS_ADMIN))
 590                return -EACCES;
 591
 592        if (efivar_attr->show) {
 593                ret = efivar_attr->show(var, buf);
 594        }
 595        return ret;
 596}
 597
 598static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 599                                const char *buf, size_t count)
 600{
 601        struct efivar_entry *var = to_efivar_entry(kobj);
 602        struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 603        ssize_t ret = -EIO;
 604
 605        if (!capable(CAP_SYS_ADMIN))
 606                return -EACCES;
 607
 608        if (efivar_attr->store)
 609                ret = efivar_attr->store(var, buf, count);
 610
 611        return ret;
 612}
 613
 614static const struct sysfs_ops efivar_attr_ops = {
 615        .show = efivar_attr_show,
 616        .store = efivar_attr_store,
 617};
 618
 619static void efivar_release(struct kobject *kobj)
 620{
 621        struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 622        kfree(var);
 623}
 624
 625static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 626static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 627static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 628static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 629static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 630
 631static struct attribute *def_attrs[] = {
 632        &efivar_attr_guid.attr,
 633        &efivar_attr_size.attr,
 634        &efivar_attr_attributes.attr,
 635        &efivar_attr_data.attr,
 636        &efivar_attr_raw_var.attr,
 637        NULL,
 638};
 639
 640static struct kobj_type efivar_ktype = {
 641        .release = efivar_release,
 642        .sysfs_ops = &efivar_attr_ops,
 643        .default_attrs = def_attrs,
 644};
 645
 646static inline void
 647efivar_unregister(struct efivar_entry *var)
 648{
 649        kobject_put(&var->kobj);
 650}
 651
 652static int efivarfs_file_open(struct inode *inode, struct file *file)
 653{
 654        file->private_data = inode->i_private;
 655        return 0;
 656}
 657
 658static int efi_status_to_err(efi_status_t status)
 659{
 660        int err;
 661
 662        switch (status) {
 663        case EFI_INVALID_PARAMETER:
 664                err = -EINVAL;
 665                break;
 666        case EFI_OUT_OF_RESOURCES:
 667                err = -ENOSPC;
 668                break;
 669        case EFI_DEVICE_ERROR:
 670                err = -EIO;
 671                break;
 672        case EFI_WRITE_PROTECTED:
 673                err = -EROFS;
 674                break;
 675        case EFI_SECURITY_VIOLATION:
 676                err = -EACCES;
 677                break;
 678        case EFI_NOT_FOUND:
 679                err = -EIO;
 680                break;
 681        default:
 682                err = -EINVAL;
 683        }
 684
 685        return err;
 686}
 687
 688static ssize_t efivarfs_file_write(struct file *file,
 689                const char __user *userbuf, size_t count, loff_t *ppos)
 690{
 691        struct efivar_entry *var = file->private_data;
 692        struct efivars *efivars;
 693        efi_status_t status;
 694        void *data;
 695        u32 attributes;
 696        struct inode *inode = file->f_mapping->host;
 697        unsigned long datasize = count - sizeof(attributes);
 698        unsigned long newdatasize, varsize;
 699        ssize_t bytes = 0;
 700
 701        if (count < sizeof(attributes))
 702                return -EINVAL;
 703
 704        if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
 705                return -EFAULT;
 706
 707        if (attributes & ~(EFI_VARIABLE_MASK))
 708                return -EINVAL;
 709
 710        efivars = var->efivars;
 711
 712        /*
 713         * Ensure that the user can't allocate arbitrarily large
 714         * amounts of memory. Pick a default size of 64K if
 715         * QueryVariableInfo() isn't supported by the firmware.
 716         */
 717
 718        varsize = datasize + ucs2_strsize(var->var.VariableName, 1024);
 719        status = check_var_size(efivars, attributes, varsize);
 720
 721        if (status != EFI_SUCCESS) {
 722                if (status != EFI_UNSUPPORTED)
 723                        return efi_status_to_err(status);
 724
 725                if (datasize > 65536)
 726                        return -ENOSPC;
 727        }
 728
 729        data = kmalloc(datasize, GFP_KERNEL);
 730        if (!data)
 731                return -ENOMEM;
 732
 733        if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
 734                bytes = -EFAULT;
 735                goto out;
 736        }
 737
 738        if (validate_var(&var->var, data, datasize) == false) {
 739                bytes = -EINVAL;
 740                goto out;
 741        }
 742
 743        /*
 744         * The lock here protects the get_variable call, the conditional
 745         * set_variable call, and removal of the variable from the efivars
 746         * list (in the case of an authenticated delete).
 747         */
 748        spin_lock_irq(&efivars->lock);
 749
 750        /*
 751         * Ensure that the available space hasn't shrunk below the safe level
 752         */
 753
 754        status = check_var_size_locked(efivars, attributes, varsize);
 755
 756        if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
 757                spin_unlock_irq(&efivars->lock);
 758                kfree(data);
 759
 760                return efi_status_to_err(status);
 761        }
 762
 763        status = efivars->ops->set_variable(var->var.VariableName,
 764                                            &var->var.VendorGuid,
 765                                            attributes, datasize,
 766                                            data);
 767
 768        if (status != EFI_SUCCESS) {
 769                spin_unlock_irq(&efivars->lock);
 770                kfree(data);
 771
 772                return efi_status_to_err(status);
 773        }
 774
 775        bytes = count;
 776
 777        /*
 778         * Writing to the variable may have caused a change in size (which
 779         * could either be an append or an overwrite), or the variable to be
 780         * deleted. Perform a GetVariable() so we can tell what actually
 781         * happened.
 782         */
 783        newdatasize = 0;
 784        status = efivars->ops->get_variable(var->var.VariableName,
 785                                            &var->var.VendorGuid,
 786                                            NULL, &newdatasize,
 787                                            NULL);
 788
 789        if (status == EFI_BUFFER_TOO_SMALL) {
 790                spin_unlock_irq(&efivars->lock);
 791                mutex_lock(&inode->i_mutex);
 792                i_size_write(inode, newdatasize + sizeof(attributes));
 793                mutex_unlock(&inode->i_mutex);
 794
 795        } else if (status == EFI_NOT_FOUND) {
 796                list_del(&var->list);
 797                spin_unlock_irq(&efivars->lock);
 798                efivar_unregister(var);
 799                drop_nlink(inode);
 800                d_delete(file->f_dentry);
 801                dput(file->f_dentry);
 802
 803        } else {
 804                spin_unlock_irq(&efivars->lock);
 805                pr_warn("efivarfs: inconsistent EFI variable implementation? "
 806                                "status = %lx\n", status);
 807        }
 808
 809out:
 810        kfree(data);
 811
 812        return bytes;
 813}
 814
 815static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 816                size_t count, loff_t *ppos)
 817{
 818        struct efivar_entry *var = file->private_data;
 819        struct efivars *efivars = var->efivars;
 820        efi_status_t status;
 821        unsigned long datasize = 0;
 822        u32 attributes;
 823        void *data;
 824        ssize_t size = 0;
 825
 826        spin_lock_irq(&efivars->lock);
 827        status = efivars->ops->get_variable(var->var.VariableName,
 828                                            &var->var.VendorGuid,
 829                                            &attributes, &datasize, NULL);
 830        spin_unlock_irq(&efivars->lock);
 831
 832        if (status != EFI_BUFFER_TOO_SMALL)
 833                return efi_status_to_err(status);
 834
 835        data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
 836
 837        if (!data)
 838                return -ENOMEM;
 839
 840        spin_lock_irq(&efivars->lock);
 841        status = efivars->ops->get_variable(var->var.VariableName,
 842                                            &var->var.VendorGuid,
 843                                            &attributes, &datasize,
 844                                            (data + sizeof(attributes)));
 845        spin_unlock_irq(&efivars->lock);
 846
 847        if (status != EFI_SUCCESS) {
 848                size = efi_status_to_err(status);
 849                goto out_free;
 850        }
 851
 852        memcpy(data, &attributes, sizeof(attributes));
 853        size = simple_read_from_buffer(userbuf, count, ppos,
 854                                       data, datasize + sizeof(attributes));
 855out_free:
 856        kfree(data);
 857
 858        return size;
 859}
 860
 861static void efivarfs_evict_inode(struct inode *inode)
 862{
 863        clear_inode(inode);
 864}
 865
 866static const struct super_operations efivarfs_ops = {
 867        .statfs = simple_statfs,
 868        .drop_inode = generic_delete_inode,
 869        .evict_inode = efivarfs_evict_inode,
 870        .show_options = generic_show_options,
 871};
 872
 873static struct super_block *efivarfs_sb;
 874
 875static const struct inode_operations efivarfs_dir_inode_operations;
 876
 877static const struct file_operations efivarfs_file_operations = {
 878        .open   = efivarfs_file_open,
 879        .read   = efivarfs_file_read,
 880        .write  = efivarfs_file_write,
 881        .llseek = no_llseek,
 882};
 883
 884static struct inode *efivarfs_get_inode(struct super_block *sb,
 885                                const struct inode *dir, int mode, dev_t dev)
 886{
 887        struct inode *inode = new_inode(sb);
 888
 889        if (inode) {
 890                inode->i_ino = get_next_ino();
 891                inode->i_mode = mode;
 892                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 893                switch (mode & S_IFMT) {
 894                case S_IFREG:
 895                        inode->i_fop = &efivarfs_file_operations;
 896                        break;
 897                case S_IFDIR:
 898                        inode->i_op = &efivarfs_dir_inode_operations;
 899                        inode->i_fop = &simple_dir_operations;
 900                        inc_nlink(inode);
 901                        break;
 902                }
 903        }
 904        return inode;
 905}
 906
 907/*
 908 * Return true if 'str' is a valid efivarfs filename of the form,
 909 *
 910 *      VariableName-12345678-1234-1234-1234-1234567891bc
 911 */
 912static bool efivarfs_valid_name(const char *str, int len)
 913{
 914        static const char dashes[GUID_LEN] = {
 915                [8] = 1, [13] = 1, [18] = 1, [23] = 1
 916        };
 917        const char *s = str + len - GUID_LEN;
 918        int i;
 919
 920        /*
 921         * We need a GUID, plus at least one letter for the variable name,
 922         * plus the '-' separator
 923         */
 924        if (len < GUID_LEN + 2)
 925                return false;
 926
 927        /* GUID must be preceded by a '-' */
 928        if (*(s - 1) != '-')
 929                return false;
 930
 931        /*
 932         * Validate that 's' is of the correct format, e.g.
 933         *
 934         *      12345678-1234-1234-1234-123456789abc
 935         */
 936        for (i = 0; i < GUID_LEN; i++) {
 937                if (dashes[i]) {
 938                        if (*s++ != '-')
 939                                return false;
 940                } else {
 941                        if (!isxdigit(*s++))
 942                                return false;
 943                }
 944        }
 945
 946        return true;
 947}
 948
 949static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
 950{
 951        guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
 952        guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
 953        guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
 954        guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
 955        guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
 956        guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
 957        guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
 958        guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
 959        guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
 960        guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
 961        guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
 962        guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
 963        guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
 964        guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
 965        guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
 966        guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
 967}
 968
 969static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 970                          umode_t mode, bool excl)
 971{
 972        struct inode *inode;
 973        struct efivars *efivars = &__efivars;
 974        struct efivar_entry *var;
 975        int namelen, i = 0, err = 0;
 976
 977        if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
 978                return -EINVAL;
 979
 980        inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
 981        if (!inode)
 982                return -ENOMEM;
 983
 984        var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 985        if (!var) {
 986                err = -ENOMEM;
 987                goto out;
 988        }
 989
 990        /* length of the variable name itself: remove GUID and separator */
 991        namelen = dentry->d_name.len - GUID_LEN - 1;
 992
 993        efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
 994                        &var->var.VendorGuid);
 995
 996        for (i = 0; i < namelen; i++)
 997                var->var.VariableName[i] = dentry->d_name.name[i];
 998
 999        var->var.VariableName[i] = '\0';
1000
1001        inode->i_private = var;
1002        var->efivars = efivars;
1003        var->kobj.kset = efivars->kset;
1004
1005        err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1006                             dentry->d_name.name);
1007        if (err)
1008                goto out;
1009
1010        kobject_uevent(&var->kobj, KOBJ_ADD);
1011        spin_lock_irq(&efivars->lock);
1012        list_add(&var->list, &efivars->list);
1013        spin_unlock_irq(&efivars->lock);
1014        d_instantiate(dentry, inode);
1015        dget(dentry);
1016out:
1017        if (err) {
1018                kfree(var);
1019                iput(inode);
1020        }
1021        return err;
1022}
1023
1024static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1025{
1026        struct efivar_entry *var = dentry->d_inode->i_private;
1027        struct efivars *efivars = var->efivars;
1028        efi_status_t status;
1029
1030        spin_lock_irq(&efivars->lock);
1031
1032        status = efivars->ops->set_variable(var->var.VariableName,
1033                                            &var->var.VendorGuid,
1034                                            0, 0, NULL);
1035
1036        if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1037                list_del(&var->list);
1038                spin_unlock_irq(&efivars->lock);
1039                efivar_unregister(var);
1040                drop_nlink(dentry->d_inode);
1041                dput(dentry);
1042                return 0;
1043        }
1044
1045        spin_unlock_irq(&efivars->lock);
1046        return -EINVAL;
1047};
1048
1049/*
1050 * Compare two efivarfs file names.
1051 *
1052 * An efivarfs filename is composed of two parts,
1053 *
1054 *      1. A case-sensitive variable name
1055 *      2. A case-insensitive GUID
1056 *
1057 * So we need to perform a case-sensitive match on part 1 and a
1058 * case-insensitive match on part 2.
1059 */
1060static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1061                              const struct dentry *dentry, const struct inode *inode,
1062                              unsigned int len, const char *str,
1063                              const struct qstr *name)
1064{
1065        int guid = len - GUID_LEN;
1066
1067        if (name->len != len)
1068                return 1;
1069
1070        /* Case-sensitive compare for the variable name */
1071        if (memcmp(str, name->name, guid))
1072                return 1;
1073
1074        /* Case-insensitive compare for the GUID */
1075        return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1076}
1077
1078static int efivarfs_d_hash(const struct dentry *dentry,
1079                           const struct inode *inode, struct qstr *qstr)
1080{
1081        unsigned long hash = init_name_hash();
1082        const unsigned char *s = qstr->name;
1083        unsigned int len = qstr->len;
1084
1085        if (!efivarfs_valid_name(s, len))
1086                return -EINVAL;
1087
1088        while (len-- > GUID_LEN)
1089                hash = partial_name_hash(*s++, hash);
1090
1091        /* GUID is case-insensitive. */
1092        while (len--)
1093                hash = partial_name_hash(tolower(*s++), hash);
1094
1095        qstr->hash = end_name_hash(hash);
1096        return 0;
1097}
1098
1099/*
1100 * Retaining negative dentries for an in-memory filesystem just wastes
1101 * memory and lookup time: arrange for them to be deleted immediately.
1102 */
1103static int efivarfs_delete_dentry(const struct dentry *dentry)
1104{
1105        return 1;
1106}
1107
1108static struct dentry_operations efivarfs_d_ops = {
1109        .d_compare = efivarfs_d_compare,
1110        .d_hash = efivarfs_d_hash,
1111        .d_delete = efivarfs_delete_dentry,
1112};
1113
1114static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1115{
1116        struct dentry *d;
1117        struct qstr q;
1118        int err;
1119
1120        q.name = name;
1121        q.len = strlen(name);
1122
1123        err = efivarfs_d_hash(NULL, NULL, &q);
1124        if (err)
1125                return ERR_PTR(err);
1126
1127        d = d_alloc(parent, &q);
1128        if (d)
1129                return d;
1130
1131        return ERR_PTR(-ENOMEM);
1132}
1133
1134static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1135{
1136        struct inode *inode = NULL;
1137        struct dentry *root;
1138        struct efivar_entry *entry, *n;
1139        struct efivars *efivars = &__efivars;
1140        char *name;
1141        int err = -ENOMEM;
1142
1143        efivarfs_sb = sb;
1144
1145        sb->s_maxbytes          = MAX_LFS_FILESIZE;
1146        sb->s_blocksize         = PAGE_CACHE_SIZE;
1147        sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1148        sb->s_magic             = EFIVARFS_MAGIC;
1149        sb->s_op                = &efivarfs_ops;
1150        sb->s_d_op              = &efivarfs_d_ops;
1151        sb->s_time_gran         = 1;
1152
1153        inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1154        if (!inode)
1155                return -ENOMEM;
1156        inode->i_op = &efivarfs_dir_inode_operations;
1157
1158        root = d_make_root(inode);
1159        sb->s_root = root;
1160        if (!root)
1161                return -ENOMEM;
1162
1163        list_for_each_entry_safe(entry, n, &efivars->list, list) {
1164                struct dentry *dentry, *root = efivarfs_sb->s_root;
1165                unsigned long size = 0;
1166                int len, i;
1167
1168                inode = NULL;
1169
1170                len = ucs2_strlen(entry->var.VariableName);
1171
1172                /* name, plus '-', plus GUID, plus NUL*/
1173                name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1174                if (!name)
1175                        goto fail;
1176
1177                for (i = 0; i < len; i++)
1178                        name[i] = entry->var.VariableName[i] & 0xFF;
1179
1180                name[len] = '-';
1181
1182                efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1183
1184                name[len+GUID_LEN+1] = '\0';
1185
1186                inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1187                                          S_IFREG | 0644, 0);
1188                if (!inode)
1189                        goto fail_name;
1190
1191                dentry = efivarfs_alloc_dentry(root, name);
1192                if (IS_ERR(dentry)) {
1193                        err = PTR_ERR(dentry);
1194                        goto fail_inode;
1195                }
1196
1197                /* copied by the above to local storage in the dentry. */
1198                kfree(name);
1199
1200                spin_lock_irq(&efivars->lock);
1201                efivars->ops->get_variable(entry->var.VariableName,
1202                                           &entry->var.VendorGuid,
1203                                           &entry->var.Attributes,
1204                                           &size,
1205                                           NULL);
1206                spin_unlock_irq(&efivars->lock);
1207
1208                mutex_lock(&inode->i_mutex);
1209                inode->i_private = entry;
1210                i_size_write(inode, size + sizeof(entry->var.Attributes));
1211                mutex_unlock(&inode->i_mutex);
1212                d_add(dentry, inode);
1213        }
1214
1215        return 0;
1216
1217fail_inode:
1218        iput(inode);
1219fail_name:
1220        kfree(name);
1221fail:
1222        return err;
1223}
1224
1225static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1226                                    int flags, const char *dev_name, void *data)
1227{
1228        return mount_single(fs_type, flags, data, efivarfs_fill_super);
1229}
1230
1231static void efivarfs_kill_sb(struct super_block *sb)
1232{
1233        kill_litter_super(sb);
1234        efivarfs_sb = NULL;
1235}
1236
1237static struct file_system_type efivarfs_type = {
1238        .name    = "efivarfs",
1239        .mount   = efivarfs_mount,
1240        .kill_sb = efivarfs_kill_sb,
1241};
1242MODULE_ALIAS_FS("efivarfs");
1243
1244/*
1245 * Handle negative dentry.
1246 */
1247static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1248                                      unsigned int flags)
1249{
1250        if (dentry->d_name.len > NAME_MAX)
1251                return ERR_PTR(-ENAMETOOLONG);
1252        d_add(dentry, NULL);
1253        return NULL;
1254}
1255
1256static const struct inode_operations efivarfs_dir_inode_operations = {
1257        .lookup = efivarfs_lookup,
1258        .unlink = efivarfs_unlink,
1259        .create = efivarfs_create,
1260};
1261
1262#ifdef CONFIG_EFI_VARS_PSTORE
1263
1264static int efi_pstore_open(struct pstore_info *psi)
1265{
1266        struct efivars *efivars = psi->data;
1267
1268        spin_lock_irq(&efivars->lock);
1269        efivars->walk_entry = list_first_entry(&efivars->list,
1270                                               struct efivar_entry, list);
1271        return 0;
1272}
1273
1274static int efi_pstore_close(struct pstore_info *psi)
1275{
1276        struct efivars *efivars = psi->data;
1277
1278        spin_unlock_irq(&efivars->lock);
1279        return 0;
1280}
1281
1282static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1283                               int *count, struct timespec *timespec,
1284                               char **buf, struct pstore_info *psi)
1285{
1286        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1287        struct efivars *efivars = psi->data;
1288        char name[DUMP_NAME_LEN];
1289        int i;
1290        int cnt;
1291        unsigned int part, size;
1292        unsigned long time;
1293
1294        while (&efivars->walk_entry->list != &efivars->list) {
1295                if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1296                                 vendor)) {
1297                        for (i = 0; i < DUMP_NAME_LEN; i++) {
1298                                name[i] = efivars->walk_entry->var.VariableName[i];
1299                        }
1300                        if (sscanf(name, "dump-type%u-%u-%d-%lu",
1301                                   type, &part, &cnt, &time) == 4) {
1302                                *id = part;
1303                                *count = cnt;
1304                                timespec->tv_sec = time;
1305                                timespec->tv_nsec = 0;
1306                        } else if (sscanf(name, "dump-type%u-%u-%lu",
1307                                   type, &part, &time) == 3) {
1308                                /*
1309                                 * Check if an old format,
1310                                 * which doesn't support holding
1311                                 * multiple logs, remains.
1312                                 */
1313                                *id = part;
1314                                *count = 0;
1315                                timespec->tv_sec = time;
1316                                timespec->tv_nsec = 0;
1317                        } else {
1318                                efivars->walk_entry = list_entry(
1319                                                efivars->walk_entry->list.next,
1320                                                struct efivar_entry, list);
1321                                continue;
1322                        }
1323
1324                        get_var_data_locked(efivars, &efivars->walk_entry->var);
1325                        size = efivars->walk_entry->var.DataSize;
1326                        *buf = kmalloc(size, GFP_KERNEL);
1327                        if (*buf == NULL)
1328                                return -ENOMEM;
1329                        memcpy(*buf, efivars->walk_entry->var.Data,
1330                               size);
1331                        efivars->walk_entry = list_entry(
1332                                        efivars->walk_entry->list.next,
1333                                        struct efivar_entry, list);
1334                        return size;
1335                }
1336                efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1337                                                 struct efivar_entry, list);
1338        }
1339        return 0;
1340}
1341
1342static int efi_pstore_write(enum pstore_type_id type,
1343                enum kmsg_dump_reason reason, u64 *id,
1344                unsigned int part, int count, size_t size,
1345                struct pstore_info *psi)
1346{
1347        char name[DUMP_NAME_LEN];
1348        efi_char16_t efi_name[DUMP_NAME_LEN];
1349        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1350        struct efivars *efivars = psi->data;
1351        int i, ret = 0;
1352        efi_status_t status = EFI_NOT_FOUND;
1353        unsigned long flags;
1354
1355        if (pstore_cannot_block_path(reason)) {
1356                /*
1357                 * If the lock is taken by another cpu in non-blocking path,
1358                 * this driver returns without entering firmware to avoid
1359                 * hanging up.
1360                 */
1361                if (!spin_trylock_irqsave(&efivars->lock, flags))
1362                        return -EBUSY;
1363        } else
1364                spin_lock_irqsave(&efivars->lock, flags);
1365
1366        /*
1367         * Check if there is a space enough to log.
1368         * size: a size of logging data
1369         * DUMP_NAME_LEN * 2: a maximum size of variable name
1370         */
1371
1372        status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1373                                         size + DUMP_NAME_LEN * 2);
1374
1375        if (status) {
1376                spin_unlock_irqrestore(&efivars->lock, flags);
1377                *id = part;
1378                return -ENOSPC;
1379        }
1380
1381        sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1382                get_seconds());
1383
1384        for (i = 0; i < DUMP_NAME_LEN; i++)
1385                efi_name[i] = name[i];
1386
1387        efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1388                                   size, psi->buf);
1389
1390        spin_unlock_irqrestore(&efivars->lock, flags);
1391
1392        if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
1393                schedule_work(&efivar_work);
1394
1395        *id = part;
1396        return ret;
1397};
1398
1399static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1400                            struct timespec time, struct pstore_info *psi)
1401{
1402        char name[DUMP_NAME_LEN];
1403        efi_char16_t efi_name[DUMP_NAME_LEN];
1404        char name_old[DUMP_NAME_LEN];
1405        efi_char16_t efi_name_old[DUMP_NAME_LEN];
1406        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1407        struct efivars *efivars = psi->data;
1408        struct efivar_entry *entry, *found = NULL;
1409        int i;
1410
1411        sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1412                time.tv_sec);
1413
1414        spin_lock_irq(&efivars->lock);
1415
1416        for (i = 0; i < DUMP_NAME_LEN; i++)
1417                efi_name[i] = name[i];
1418
1419        /*
1420         * Clean up an entry with the same name
1421         */
1422
1423        list_for_each_entry(entry, &efivars->list, list) {
1424                get_var_data_locked(efivars, &entry->var);
1425
1426                if (efi_guidcmp(entry->var.VendorGuid, vendor))
1427                        continue;
1428                if (ucs2_strncmp(entry->var.VariableName, efi_name,
1429                                  ucs2_strlen(efi_name))) {
1430                        /*
1431                         * Check if an old format,
1432                         * which doesn't support holding
1433                         * multiple logs, remains.
1434                         */
1435                        sprintf(name_old, "dump-type%u-%u-%lu", type,
1436                                (unsigned int)id, time.tv_sec);
1437
1438                        for (i = 0; i < DUMP_NAME_LEN; i++)
1439                                efi_name_old[i] = name_old[i];
1440
1441                        if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
1442                                          ucs2_strlen(efi_name_old)))
1443                                continue;
1444                }
1445
1446                /* found */
1447                found = entry;
1448                efivars->ops->set_variable(entry->var.VariableName,
1449                                           &entry->var.VendorGuid,
1450                                           PSTORE_EFI_ATTRIBUTES,
1451                                           0, NULL);
1452                break;
1453        }
1454
1455        if (found)
1456                list_del(&found->list);
1457
1458        spin_unlock_irq(&efivars->lock);
1459
1460        if (found)
1461                efivar_unregister(found);
1462
1463        return 0;
1464}
1465
1466static struct pstore_info efi_pstore_info = {
1467        .owner          = THIS_MODULE,
1468        .name           = "efi",
1469        .open           = efi_pstore_open,
1470        .close          = efi_pstore_close,
1471        .read           = efi_pstore_read,
1472        .write          = efi_pstore_write,
1473        .erase          = efi_pstore_erase,
1474};
1475
1476static void efivar_pstore_register(struct efivars *efivars)
1477{
1478        efivars->efi_pstore_info = efi_pstore_info;
1479        efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1480        if (efivars->efi_pstore_info.buf) {
1481                efivars->efi_pstore_info.bufsize = 1024;
1482                efivars->efi_pstore_info.data = efivars;
1483                spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1484                pstore_register(&efivars->efi_pstore_info);
1485        }
1486}
1487#else
1488static void efivar_pstore_register(struct efivars *efivars)
1489{
1490        return;
1491}
1492#endif
1493
1494static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1495                             struct bin_attribute *bin_attr,
1496                             char *buf, loff_t pos, size_t count)
1497{
1498        struct efi_variable *new_var = (struct efi_variable *)buf;
1499        struct efivars *efivars = bin_attr->private;
1500        struct efivar_entry *search_efivar, *n;
1501        unsigned long strsize1, strsize2;
1502        efi_status_t status = EFI_NOT_FOUND;
1503        int found = 0;
1504
1505        if (!capable(CAP_SYS_ADMIN))
1506                return -EACCES;
1507
1508        if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1509            validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1510                printk(KERN_ERR "efivars: Malformed variable content\n");
1511                return -EINVAL;
1512        }
1513
1514        spin_lock_irq(&efivars->lock);
1515
1516        /*
1517         * Does this variable already exist?
1518         */
1519        list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1520                strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
1521                strsize2 = ucs2_strsize(new_var->VariableName, 1024);
1522                if (strsize1 == strsize2 &&
1523                        !memcmp(&(search_efivar->var.VariableName),
1524                                new_var->VariableName, strsize1) &&
1525                        !efi_guidcmp(search_efivar->var.VendorGuid,
1526                                new_var->VendorGuid)) {
1527                        found = 1;
1528                        break;
1529                }
1530        }
1531        if (found) {
1532                spin_unlock_irq(&efivars->lock);
1533                return -EINVAL;
1534        }
1535
1536        status = check_var_size_locked(efivars, new_var->Attributes,
1537               new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
1538
1539        if (status && status != EFI_UNSUPPORTED) {
1540                spin_unlock_irq(&efivars->lock);
1541                return efi_status_to_err(status);
1542        }
1543
1544        /* now *really* create the variable via EFI */
1545        status = efivars->ops->set_variable(new_var->VariableName,
1546                                            &new_var->VendorGuid,
1547                                            new_var->Attributes,
1548                                            new_var->DataSize,
1549                                            new_var->Data);
1550
1551        if (status != EFI_SUCCESS) {
1552                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1553                        status);
1554                spin_unlock_irq(&efivars->lock);
1555                return -EIO;
1556        }
1557        spin_unlock_irq(&efivars->lock);
1558
1559        /* Create the entry in sysfs.  Locking is not required here */
1560        status = efivar_create_sysfs_entry(efivars,
1561                                           ucs2_strsize(new_var->VariableName,
1562                                                         1024),
1563                                           new_var->VariableName,
1564                                           &new_var->VendorGuid);
1565        if (status) {
1566                printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1567        }
1568        return count;
1569}
1570
1571static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1572                             struct bin_attribute *bin_attr,
1573                             char *buf, loff_t pos, size_t count)
1574{
1575        struct efi_variable *del_var = (struct efi_variable *)buf;
1576        struct efivars *efivars = bin_attr->private;
1577        struct efivar_entry *search_efivar, *n;
1578        unsigned long strsize1, strsize2;
1579        efi_status_t status = EFI_NOT_FOUND;
1580        int found = 0;
1581
1582        if (!capable(CAP_SYS_ADMIN))
1583                return -EACCES;
1584
1585        spin_lock_irq(&efivars->lock);
1586
1587        /*
1588         * Does this variable already exist?
1589         */
1590        list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1591                strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
1592                strsize2 = ucs2_strsize(del_var->VariableName, 1024);
1593                if (strsize1 == strsize2 &&
1594                        !memcmp(&(search_efivar->var.VariableName),
1595                                del_var->VariableName, strsize1) &&
1596                        !efi_guidcmp(search_efivar->var.VendorGuid,
1597                                del_var->VendorGuid)) {
1598                        found = 1;
1599                        break;
1600                }
1601        }
1602        if (!found) {
1603                spin_unlock_irq(&efivars->lock);
1604                return -EINVAL;
1605        }
1606        /* force the Attributes/DataSize to 0 to ensure deletion */
1607        del_var->Attributes = 0;
1608        del_var->DataSize = 0;
1609
1610        status = efivars->ops->set_variable(del_var->VariableName,
1611                                            &del_var->VendorGuid,
1612                                            del_var->Attributes,
1613                                            del_var->DataSize,
1614                                            del_var->Data);
1615
1616        if (status != EFI_SUCCESS) {
1617                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1618                        status);
1619                spin_unlock_irq(&efivars->lock);
1620                return -EIO;
1621        }
1622        list_del(&search_efivar->list);
1623        /* We need to release this lock before unregistering. */
1624        spin_unlock_irq(&efivars->lock);
1625        efivar_unregister(search_efivar);
1626
1627        /* It's dead Jim.... */
1628        return count;
1629}
1630
1631static bool variable_is_present(struct efivars *efivars,
1632                                efi_char16_t *variable_name,
1633                                efi_guid_t *vendor)
1634{
1635        struct efivar_entry *entry, *n;
1636        unsigned long strsize1, strsize2;
1637        bool found = false;
1638
1639        strsize1 = ucs2_strsize(variable_name, 1024);
1640        list_for_each_entry_safe(entry, n, &efivars->list, list) {
1641                strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
1642                if (strsize1 == strsize2 &&
1643                        !memcmp(variable_name, &(entry->var.VariableName),
1644                                strsize2) &&
1645                        !efi_guidcmp(entry->var.VendorGuid,
1646                                *vendor)) {
1647                        found = true;
1648                        break;
1649                }
1650        }
1651        return found;
1652}
1653
1654/*
1655 * Returns the size of variable_name, in bytes, including the
1656 * terminating NULL character, or variable_name_size if no NULL
1657 * character is found among the first variable_name_size bytes.
1658 */
1659static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1660                                       unsigned long variable_name_size)
1661{
1662        unsigned long len;
1663        efi_char16_t c;
1664
1665        /*
1666         * The variable name is, by definition, a NULL-terminated
1667         * string, so make absolutely sure that variable_name_size is
1668         * the value we expect it to be. If not, return the real size.
1669         */
1670        for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1671                c = variable_name[(len / sizeof(c)) - 1];
1672                if (!c)
1673                        break;
1674        }
1675
1676        return min(len, variable_name_size);
1677}
1678
1679static void efivar_update_sysfs_entries(struct work_struct *work)
1680{
1681        struct efivars *efivars = &__efivars;
1682        efi_guid_t vendor;
1683        efi_char16_t *variable_name;
1684        unsigned long variable_name_size = 1024;
1685        efi_status_t status = EFI_NOT_FOUND;
1686        bool found;
1687
1688        /* Add new sysfs entries */
1689        while (1) {
1690                variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1691                if (!variable_name) {
1692                        pr_err("efivars: Memory allocation failed.\n");
1693                        return;
1694                }
1695
1696                spin_lock_irq(&efivars->lock);
1697                found = false;
1698                while (1) {
1699                        variable_name_size = 1024;
1700                        status = efivars->ops->get_next_variable(
1701                                                        &variable_name_size,
1702                                                        variable_name,
1703                                                        &vendor);
1704                        if (status != EFI_SUCCESS) {
1705                                break;
1706                        } else {
1707                                if (!variable_is_present(efivars,
1708                                    variable_name, &vendor)) {
1709                                        found = true;
1710                                        break;
1711                                }
1712                        }
1713                }
1714                spin_unlock_irq(&efivars->lock);
1715
1716                if (!found) {
1717                        kfree(variable_name);
1718                        break;
1719                } else {
1720                        variable_name_size = var_name_strnsize(variable_name,
1721                                                               variable_name_size);
1722                        efivar_create_sysfs_entry(efivars,
1723                                                  variable_name_size,
1724                                                  variable_name, &vendor);
1725                }
1726        }
1727}
1728
1729/*
1730 * Let's not leave out systab information that snuck into
1731 * the efivars driver
1732 */
1733static ssize_t systab_show(struct kobject *kobj,
1734                           struct kobj_attribute *attr, char *buf)
1735{
1736        char *str = buf;
1737
1738        if (!kobj || !buf)
1739                return -EINVAL;
1740
1741        if (efi.mps != EFI_INVALID_TABLE_ADDR)
1742                str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1743        if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1744                str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1745        if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1746                str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1747        if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1748                str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1749        if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1750                str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1751        if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1752                str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1753        if (efi.uga != EFI_INVALID_TABLE_ADDR)
1754                str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1755
1756        return str - buf;
1757}
1758
1759static struct kobj_attribute efi_attr_systab =
1760                        __ATTR(systab, 0400, systab_show, NULL);
1761
1762static struct attribute *efi_subsys_attrs[] = {
1763        &efi_attr_systab.attr,
1764        NULL,   /* maybe more in the future? */
1765};
1766
1767static struct attribute_group efi_subsys_attr_group = {
1768        .attrs = efi_subsys_attrs,
1769};
1770
1771static struct kobject *efi_kobj;
1772
1773/*
1774 * efivar_create_sysfs_entry()
1775 * Requires:
1776 *    variable_name_size = number of bytes required to hold
1777 *                         variable_name (not counting the NULL
1778 *                         character at the end.
1779 *    efivars->lock is not held on entry or exit.
1780 * Returns 1 on failure, 0 on success
1781 */
1782static int
1783efivar_create_sysfs_entry(struct efivars *efivars,
1784                          unsigned long variable_name_size,
1785                          efi_char16_t *variable_name,
1786                          efi_guid_t *vendor_guid)
1787{
1788        int i, short_name_size;
1789        char *short_name;
1790        struct efivar_entry *new_efivar;
1791
1792        /*
1793         * Length of the variable bytes in ASCII, plus the '-' separator,
1794         * plus the GUID, plus trailing NUL
1795         */
1796        short_name_size = variable_name_size / sizeof(efi_char16_t)
1797                                + 1 + GUID_LEN + 1;
1798
1799        short_name = kzalloc(short_name_size, GFP_KERNEL);
1800        new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1801
1802        if (!short_name || !new_efivar)  {
1803                kfree(short_name);
1804                kfree(new_efivar);
1805                return 1;
1806        }
1807
1808        new_efivar->efivars = efivars;
1809        memcpy(new_efivar->var.VariableName, variable_name,
1810                variable_name_size);
1811        memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1812
1813        /* Convert Unicode to normal chars (assume top bits are 0),
1814           ala UTF-8 */
1815        for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1816                short_name[i] = variable_name[i] & 0xFF;
1817        }
1818        /* This is ugly, but necessary to separate one vendor's
1819           private variables from another's.         */
1820
1821        *(short_name + strlen(short_name)) = '-';
1822        efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1823
1824        new_efivar->kobj.kset = efivars->kset;
1825        i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1826                                 "%s", short_name);
1827        if (i) {
1828                kfree(short_name);
1829                kfree(new_efivar);
1830                return 1;
1831        }
1832
1833        kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1834        kfree(short_name);
1835        short_name = NULL;
1836
1837        spin_lock_irq(&efivars->lock);
1838        list_add(&new_efivar->list, &efivars->list);
1839        spin_unlock_irq(&efivars->lock);
1840
1841        return 0;
1842}
1843
1844static int
1845create_efivars_bin_attributes(struct efivars *efivars)
1846{
1847        struct bin_attribute *attr;
1848        int error;
1849
1850        /* new_var */
1851        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1852        if (!attr)
1853                return -ENOMEM;
1854
1855        attr->attr.name = "new_var";
1856        attr->attr.mode = 0200;
1857        attr->write = efivar_create;
1858        attr->private = efivars;
1859        efivars->new_var = attr;
1860
1861        /* del_var */
1862        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1863        if (!attr) {
1864                error = -ENOMEM;
1865                goto out_free;
1866        }
1867        attr->attr.name = "del_var";
1868        attr->attr.mode = 0200;
1869        attr->write = efivar_delete;
1870        attr->private = efivars;
1871        efivars->del_var = attr;
1872
1873        sysfs_bin_attr_init(efivars->new_var);
1874        sysfs_bin_attr_init(efivars->del_var);
1875
1876        /* Register */
1877        error = sysfs_create_bin_file(&efivars->kset->kobj,
1878                                      efivars->new_var);
1879        if (error) {
1880                printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1881                        " due to error %d\n", error);
1882                goto out_free;
1883        }
1884        error = sysfs_create_bin_file(&efivars->kset->kobj,
1885                                      efivars->del_var);
1886        if (error) {
1887                printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1888                        " due to error %d\n", error);
1889                sysfs_remove_bin_file(&efivars->kset->kobj,
1890                                      efivars->new_var);
1891                goto out_free;
1892        }
1893
1894        return 0;
1895out_free:
1896        kfree(efivars->del_var);
1897        efivars->del_var = NULL;
1898        kfree(efivars->new_var);
1899        efivars->new_var = NULL;
1900        return error;
1901}
1902
1903void unregister_efivars(struct efivars *efivars)
1904{
1905        struct efivar_entry *entry, *n;
1906
1907        list_for_each_entry_safe(entry, n, &efivars->list, list) {
1908                spin_lock_irq(&efivars->lock);
1909                list_del(&entry->list);
1910                spin_unlock_irq(&efivars->lock);
1911                efivar_unregister(entry);
1912        }
1913        if (efivars->new_var)
1914                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1915        if (efivars->del_var)
1916                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1917        kfree(efivars->new_var);
1918        kfree(efivars->del_var);
1919        kobject_put(efivars->kobject);
1920        kset_unregister(efivars->kset);
1921}
1922EXPORT_SYMBOL_GPL(unregister_efivars);
1923
1924/*
1925 * Print a warning when duplicate EFI variables are encountered and
1926 * disable the sysfs workqueue since the firmware is buggy.
1927 */
1928static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1929                             unsigned long len16)
1930{
1931        size_t i, len8 = len16 / sizeof(efi_char16_t);
1932        char *s8;
1933
1934        /*
1935         * Disable the workqueue since the algorithm it uses for
1936         * detecting new variables won't work with this buggy
1937         * implementation of GetNextVariableName().
1938         */
1939        efivar_wq_enabled = false;
1940
1941        s8 = kzalloc(len8, GFP_KERNEL);
1942        if (!s8)
1943                return;
1944
1945        for (i = 0; i < len8; i++)
1946                s8[i] = s16[i];
1947
1948        printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
1949               s8, vendor_guid);
1950        kfree(s8);
1951}
1952
1953int register_efivars(struct efivars *efivars,
1954                     const struct efivar_operations *ops,
1955                     struct kobject *parent_kobj)
1956{
1957        efi_status_t status = EFI_NOT_FOUND;
1958        efi_guid_t vendor_guid;
1959        efi_char16_t *variable_name;
1960        unsigned long variable_name_size = 1024;
1961        int error = 0;
1962
1963        variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1964        if (!variable_name) {
1965                printk(KERN_ERR "efivars: Memory allocation failed.\n");
1966                return -ENOMEM;
1967        }
1968
1969        spin_lock_init(&efivars->lock);
1970        INIT_LIST_HEAD(&efivars->list);
1971        efivars->ops = ops;
1972
1973        efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1974        if (!efivars->kset) {
1975                printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1976                error = -ENOMEM;
1977                goto out;
1978        }
1979
1980        efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1981        if (!efivars->kobject) {
1982                pr_err("efivars: Subsystem registration failed.\n");
1983                error = -ENOMEM;
1984                kset_unregister(efivars->kset);
1985                goto out;
1986        }
1987
1988        /*
1989         * Per EFI spec, the maximum storage allocated for both
1990         * the variable name and variable data is 1024 bytes.
1991         */
1992
1993        do {
1994                variable_name_size = 1024;
1995
1996                status = ops->get_next_variable(&variable_name_size,
1997                                                variable_name,
1998                                                &vendor_guid);
1999                switch (status) {
2000                case EFI_SUCCESS:
2001                        variable_name_size = var_name_strnsize(variable_name,
2002                                                               variable_name_size);
2003
2004                        /*
2005                         * Some firmware implementations return the
2006                         * same variable name on multiple calls to
2007                         * get_next_variable(). Terminate the loop
2008                         * immediately as there is no guarantee that
2009                         * we'll ever see a different variable name,
2010                         * and may end up looping here forever.
2011                         */
2012                        if (variable_is_present(efivars, variable_name,
2013                                                &vendor_guid)) {
2014                                dup_variable_bug(variable_name, &vendor_guid,
2015                                                 variable_name_size);
2016                                status = EFI_NOT_FOUND;
2017                                break;
2018                        }
2019
2020                        efivar_create_sysfs_entry(efivars,
2021                                                  variable_name_size,
2022                                                  variable_name,
2023                                                  &vendor_guid);
2024                        break;
2025                case EFI_NOT_FOUND:
2026                        break;
2027                default:
2028                        printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
2029                                status);
2030                        status = EFI_NOT_FOUND;
2031                        break;
2032                }
2033        } while (status != EFI_NOT_FOUND);
2034
2035        error = create_efivars_bin_attributes(efivars);
2036        if (error)
2037                unregister_efivars(efivars);
2038
2039        if (!efivars_pstore_disable)
2040                efivar_pstore_register(efivars);
2041
2042        register_filesystem(&efivarfs_type);
2043
2044out:
2045        kfree(variable_name);
2046
2047        return error;
2048}
2049EXPORT_SYMBOL_GPL(register_efivars);
2050
2051/*
2052 * For now we register the efi subsystem with the firmware subsystem
2053 * and the vars subsystem with the efi subsystem.  In the future, it
2054 * might make sense to split off the efi subsystem into its own
2055 * driver, but for now only efivars will register with it, so just
2056 * include it here.
2057 */
2058
2059static int __init
2060efivars_init(void)
2061{
2062        int error = 0;
2063
2064        printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2065               EFIVARS_DATE);
2066
2067        if (!efi_enabled(EFI_RUNTIME_SERVICES))
2068                return 0;
2069
2070        /* For now we'll register the efi directory at /sys/firmware/efi */
2071        efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2072        if (!efi_kobj) {
2073                printk(KERN_ERR "efivars: Firmware registration failed.\n");
2074                return -ENOMEM;
2075        }
2076
2077        ops.get_variable = efi.get_variable;
2078        ops.set_variable = efi.set_variable;
2079        ops.get_next_variable = efi.get_next_variable;
2080        ops.query_variable_store = efi_query_variable_store;
2081
2082        error = register_efivars(&__efivars, &ops, efi_kobj);
2083        if (error)
2084                goto err_put;
2085
2086        /* Don't forget the systab entry */
2087        error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2088        if (error) {
2089                printk(KERN_ERR
2090                       "efivars: Sysfs attribute export failed with error %d.\n",
2091                       error);
2092                goto err_unregister;
2093        }
2094
2095        return 0;
2096
2097err_unregister:
2098        unregister_efivars(&__efivars);
2099err_put:
2100        kobject_put(efi_kobj);
2101        return error;
2102}
2103
2104static void __exit
2105efivars_exit(void)
2106{
2107        cancel_work_sync(&efivar_work);
2108
2109        if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2110                unregister_efivars(&__efivars);
2111                kobject_put(efi_kobj);
2112        }
2113}
2114
2115module_init(efivars_init);
2116module_exit(efivars_exit);
2117
2118
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