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