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 <asm/uaccess.h>
  84
  85#define EFIVARS_VERSION "0.08"
  86#define EFIVARS_DATE "2004-May-17"
  87
  88MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  89MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  90MODULE_LICENSE("GPL");
  91MODULE_VERSION(EFIVARS_VERSION);
  92
  93#define DUMP_NAME_LEN 52
  94
  95/*
  96 * The maximum size of VariableName + Data = 1024
  97 * Therefore, it's reasonable to save that much
  98 * space in each part of the structure,
  99 * and we use a page for reading/writing.
 100 */
 101
 102struct efi_variable {
 103        efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 104        efi_guid_t    VendorGuid;
 105        unsigned long DataSize;
 106        __u8          Data[1024];
 107        efi_status_t  Status;
 108        __u32         Attributes;
 109} __attribute__((packed));
 110
 111
 112struct efivar_entry {
 113        struct efivars *efivars;
 114        struct efi_variable var;
 115        struct list_head list;
 116        struct kobject kobj;
 117};
 118
 119struct efivar_attribute {
 120        struct attribute attr;
 121        ssize_t (*show) (struct efivar_entry *entry, char *buf);
 122        ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 123};
 124
 125#define PSTORE_EFI_ATTRIBUTES \
 126        (EFI_VARIABLE_NON_VOLATILE | \
 127         EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 128         EFI_VARIABLE_RUNTIME_ACCESS)
 129
 130#define EFIVAR_ATTR(_name, _mode, _show, _store) \
 131struct efivar_attribute efivar_attr_##_name = { \
 132        .attr = {.name = __stringify(_name), .mode = _mode}, \
 133        .show = _show, \
 134        .store = _store, \
 135};
 136
 137#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 138#define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 139
 140/*
 141 * Prototype for sysfs creation function
 142 */
 143static int
 144efivar_create_sysfs_entry(struct efivars *efivars,
 145                          unsigned long variable_name_size,
 146                          efi_char16_t *variable_name,
 147                          efi_guid_t *vendor_guid);
 148
 149/* Return the number of unicode characters in data */
 150static unsigned long
 151utf16_strnlen(efi_char16_t *s, size_t maxlength)
 152{
 153        unsigned long length = 0;
 154
 155        while (*s++ != 0 && length < maxlength)
 156                length++;
 157        return length;
 158}
 159
 160static inline unsigned long
 161utf16_strlen(efi_char16_t *s)
 162{
 163        return utf16_strnlen(s, ~0UL);
 164}
 165
 166/*
 167 * Return the number of bytes is the length of this string
 168 * Note: this is NOT the same as the number of unicode characters
 169 */
 170static inline unsigned long
 171utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 172{
 173        return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 174}
 175
 176static inline int
 177utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 178{
 179        while (1) {
 180                if (len == 0)
 181                        return 0;
 182                if (*a < *b)
 183                        return -1;
 184                if (*a > *b)
 185                        return 1;
 186                if (*a == 0) /* implies *b == 0 */
 187                        return 0;
 188                a++;
 189                b++;
 190                len--;
 191        }
 192}
 193
 194static bool
 195validate_device_path(struct efi_variable *var, int match, u8 *buffer,
 196                     unsigned long len)
 197{
 198        struct efi_generic_dev_path *node;
 199        int offset = 0;
 200
 201        node = (struct efi_generic_dev_path *)buffer;
 202
 203        if (len < sizeof(*node))
 204                return false;
 205
 206        while (offset <= len - sizeof(*node) &&
 207               node->length >= sizeof(*node) &&
 208                node->length <= len - offset) {
 209                offset += node->length;
 210
 211                if ((node->type == EFI_DEV_END_PATH ||
 212                     node->type == EFI_DEV_END_PATH2) &&
 213                    node->sub_type == EFI_DEV_END_ENTIRE)
 214                        return true;
 215
 216                node = (struct efi_generic_dev_path *)(buffer + offset);
 217        }
 218
 219        /*
 220         * If we're here then either node->length pointed past the end
 221         * of the buffer or we reached the end of the buffer without
 222         * finding a device path end node.
 223         */
 224        return false;
 225}
 226
 227static bool
 228validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
 229                    unsigned long len)
 230{
 231        /* An array of 16-bit integers */
 232        if ((len % 2) != 0)
 233                return false;
 234
 235        return true;
 236}
 237
 238static bool
 239validate_load_option(struct efi_variable *var, int match, u8 *buffer,
 240                     unsigned long len)
 241{
 242        u16 filepathlength;
 243        int i, desclength = 0, namelen;
 244
 245        namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
 246
 247        /* Either "Boot" or "Driver" followed by four digits of hex */
 248        for (i = match; i < match+4; i++) {
 249                if (var->VariableName[i] > 127 ||
 250                    hex_to_bin(var->VariableName[i] & 0xff) < 0)
 251                        return true;
 252        }
 253
 254        /* Reject it if there's 4 digits of hex and then further content */
 255        if (namelen > match + 4)
 256                return false;
 257
 258        /* A valid entry must be at least 8 bytes */
 259        if (len < 8)
 260                return false;
 261
 262        filepathlength = buffer[4] | buffer[5] << 8;
 263
 264        /*
 265         * There's no stored length for the description, so it has to be
 266         * found by hand
 267         */
 268        desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 269
 270        /* Each boot entry must have a descriptor */
 271        if (!desclength)
 272                return false;
 273
 274        /*
 275         * If the sum of the length of the description, the claimed filepath
 276         * length and the original header are greater than the length of the
 277         * variable, it's malformed
 278         */
 279        if ((desclength + filepathlength + 6) > len)
 280                return false;
 281
 282        /*
 283         * And, finally, check the filepath
 284         */
 285        return validate_device_path(var, match, buffer + desclength + 6,
 286                                    filepathlength);
 287}
 288
 289static bool
 290validate_uint16(struct efi_variable *var, int match, u8 *buffer,
 291                unsigned long len)
 292{
 293        /* A single 16-bit integer */
 294        if (len != 2)
 295                return false;
 296
 297        return true;
 298}
 299
 300static bool
 301validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
 302                      unsigned long len)
 303{
 304        int i;
 305
 306        for (i = 0; i < len; i++) {
 307                if (buffer[i] > 127)
 308                        return false;
 309
 310                if (buffer[i] == 0)
 311                        return true;
 312        }
 313
 314        return false;
 315}
 316
 317struct variable_validate {
 318        char *name;
 319        bool (*validate)(struct efi_variable *var, int match, u8 *data,
 320                         unsigned long len);
 321};
 322
 323static const struct variable_validate variable_validate[] = {
 324        { "BootNext", validate_uint16 },
 325        { "BootOrder", validate_boot_order },
 326        { "DriverOrder", validate_boot_order },
 327        { "Boot*", validate_load_option },
 328        { "Driver*", validate_load_option },
 329        { "ConIn", validate_device_path },
 330        { "ConInDev", validate_device_path },
 331        { "ConOut", validate_device_path },
 332        { "ConOutDev", validate_device_path },
 333        { "ErrOut", validate_device_path },
 334        { "ErrOutDev", validate_device_path },
 335        { "Timeout", validate_uint16 },
 336        { "Lang", validate_ascii_string },
 337        { "PlatformLang", validate_ascii_string },
 338        { "", NULL },
 339};
 340
 341static bool
 342validate_var(struct efi_variable *var, u8 *data, unsigned long len)
 343{
 344        int i;
 345        u16 *unicode_name = var->VariableName;
 346
 347        for (i = 0; variable_validate[i].validate != NULL; i++) {
 348                const char *name = variable_validate[i].name;
 349                int match;
 350
 351                for (match = 0; ; match++) {
 352                        char c = name[match];
 353                        u16 u = unicode_name[match];
 354
 355                        /* All special variables are plain ascii */
 356                        if (u > 127)
 357                                return true;
 358
 359                        /* Wildcard in the matching name means we've matched */
 360                        if (c == '*')
 361                                return variable_validate[i].validate(var,
 362                                                             match, data, len);
 363
 364                        /* Case sensitive match */
 365                        if (c != u)
 366                                break;
 367
 368                        /* Reached the end of the string while matching */
 369                        if (!c)
 370                                return variable_validate[i].validate(var,
 371                                                             match, data, len);
 372                }
 373        }
 374
 375        return true;
 376}
 377
 378static efi_status_t
 379get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 380{
 381        efi_status_t status;
 382
 383        var->DataSize = 1024;
 384        status = efivars->ops->get_variable(var->VariableName,
 385                                            &var->VendorGuid,
 386                                            &var->Attributes,
 387                                            &var->DataSize,
 388                                            var->Data);
 389        return status;
 390}
 391
 392static efi_status_t
 393get_var_data(struct efivars *efivars, struct efi_variable *var)
 394{
 395        efi_status_t status;
 396
 397        spin_lock(&efivars->lock);
 398        status = get_var_data_locked(efivars, var);
 399        spin_unlock(&efivars->lock);
 400
 401        if (status != EFI_SUCCESS) {
 402                printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 403                        status);
 404        }
 405        return status;
 406}
 407
 408static ssize_t
 409efivar_guid_read(struct efivar_entry *entry, char *buf)
 410{
 411        struct efi_variable *var = &entry->var;
 412        char *str = buf;
 413
 414        if (!entry || !buf)
 415                return 0;
 416
 417        efi_guid_unparse(&var->VendorGuid, str);
 418        str += strlen(str);
 419        str += sprintf(str, "\n");
 420
 421        return str - buf;
 422}
 423
 424static ssize_t
 425efivar_attr_read(struct efivar_entry *entry, char *buf)
 426{
 427        struct efi_variable *var = &entry->var;
 428        char *str = buf;
 429        efi_status_t status;
 430
 431        if (!entry || !buf)
 432                return -EINVAL;
 433
 434        status = get_var_data(entry->efivars, var);
 435        if (status != EFI_SUCCESS)
 436                return -EIO;
 437
 438        if (var->Attributes & 0x1)
 439                str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 440        if (var->Attributes & 0x2)
 441                str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 442        if (var->Attributes & 0x4)
 443                str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 444        return str - buf;
 445}
 446
 447static ssize_t
 448efivar_size_read(struct efivar_entry *entry, char *buf)
 449{
 450        struct efi_variable *var = &entry->var;
 451        char *str = buf;
 452        efi_status_t status;
 453
 454        if (!entry || !buf)
 455                return -EINVAL;
 456
 457        status = get_var_data(entry->efivars, var);
 458        if (status != EFI_SUCCESS)
 459                return -EIO;
 460
 461        str += sprintf(str, "0x%lx\n", var->DataSize);
 462        return str - buf;
 463}
 464
 465static ssize_t
 466efivar_data_read(struct efivar_entry *entry, char *buf)
 467{
 468        struct efi_variable *var = &entry->var;
 469        efi_status_t status;
 470
 471        if (!entry || !buf)
 472                return -EINVAL;
 473
 474        status = get_var_data(entry->efivars, var);
 475        if (status != EFI_SUCCESS)
 476                return -EIO;
 477
 478        memcpy(buf, var->Data, var->DataSize);
 479        return var->DataSize;
 480}
 481/*
 482 * We allow each variable to be edited via rewriting the
 483 * entire efi variable structure.
 484 */
 485static ssize_t
 486efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 487{
 488        struct efi_variable *new_var, *var = &entry->var;
 489        struct efivars *efivars = entry->efivars;
 490        efi_status_t status = EFI_NOT_FOUND;
 491
 492        if (count != sizeof(struct efi_variable))
 493                return -EINVAL;
 494
 495        new_var = (struct efi_variable *)buf;
 496        /*
 497         * If only updating the variable data, then the name
 498         * and guid should remain the same
 499         */
 500        if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 501                efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 502                printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 503                return -EINVAL;
 504        }
 505
 506        if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 507                printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 508                return -EINVAL;
 509        }
 510
 511        if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 512            validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 513                printk(KERN_ERR "efivars: Malformed variable content\n");
 514                return -EINVAL;
 515        }
 516
 517        spin_lock(&efivars->lock);
 518        status = efivars->ops->set_variable(new_var->VariableName,
 519                                            &new_var->VendorGuid,
 520                                            new_var->Attributes,
 521                                            new_var->DataSize,
 522                                            new_var->Data);
 523
 524        spin_unlock(&efivars->lock);
 525
 526        if (status != EFI_SUCCESS) {
 527                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 528                        status);
 529                return -EIO;
 530        }
 531
 532        memcpy(&entry->var, new_var, count);
 533        return count;
 534}
 535
 536static ssize_t
 537efivar_show_raw(struct efivar_entry *entry, char *buf)
 538{
 539        struct efi_variable *var = &entry->var;
 540        efi_status_t status;
 541
 542        if (!entry || !buf)
 543                return 0;
 544
 545        status = get_var_data(entry->efivars, var);
 546        if (status != EFI_SUCCESS)
 547                return -EIO;
 548
 549        memcpy(buf, var, sizeof(*var));
 550        return sizeof(*var);
 551}
 552
 553/*
 554 * Generic read/write functions that call the specific functions of
 555 * the attributes...
 556 */
 557static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 558                                char *buf)
 559{
 560        struct efivar_entry *var = to_efivar_entry(kobj);
 561        struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 562        ssize_t ret = -EIO;
 563
 564        if (!capable(CAP_SYS_ADMIN))
 565                return -EACCES;
 566
 567        if (efivar_attr->show) {
 568                ret = efivar_attr->show(var, buf);
 569        }
 570        return ret;
 571}
 572
 573static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 574                                const char *buf, size_t count)
 575{
 576        struct efivar_entry *var = to_efivar_entry(kobj);
 577        struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 578        ssize_t ret = -EIO;
 579
 580        if (!capable(CAP_SYS_ADMIN))
 581                return -EACCES;
 582
 583        if (efivar_attr->store)
 584                ret = efivar_attr->store(var, buf, count);
 585
 586        return ret;
 587}
 588
 589static const struct sysfs_ops efivar_attr_ops = {
 590        .show = efivar_attr_show,
 591        .store = efivar_attr_store,
 592};
 593
 594static void efivar_release(struct kobject *kobj)
 595{
 596        struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 597        kfree(var);
 598}
 599
 600static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 601static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 602static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 603static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 604static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 605
 606static struct attribute *def_attrs[] = {
 607        &efivar_attr_guid.attr,
 608        &efivar_attr_size.attr,
 609        &efivar_attr_attributes.attr,
 610        &efivar_attr_data.attr,
 611        &efivar_attr_raw_var.attr,
 612        NULL,
 613};
 614
 615static struct kobj_type efivar_ktype = {
 616        .release = efivar_release,
 617        .sysfs_ops = &efivar_attr_ops,
 618        .default_attrs = def_attrs,
 619};
 620
 621static struct pstore_info efi_pstore_info;
 622
 623static inline void
 624efivar_unregister(struct efivar_entry *var)
 625{
 626        kobject_put(&var->kobj);
 627}
 628
 629#ifdef CONFIG_PSTORE
 630
 631static int efi_pstore_open(struct pstore_info *psi)
 632{
 633        struct efivars *efivars = psi->data;
 634
 635        spin_lock(&efivars->lock);
 636        efivars->walk_entry = list_first_entry(&efivars->list,
 637                                               struct efivar_entry, list);
 638        return 0;
 639}
 640
 641static int efi_pstore_close(struct pstore_info *psi)
 642{
 643        struct efivars *efivars = psi->data;
 644
 645        spin_unlock(&efivars->lock);
 646        return 0;
 647}
 648
 649static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 650                               struct timespec *timespec,
 651                               char **buf, struct pstore_info *psi)
 652{
 653        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 654        struct efivars *efivars = psi->data;
 655        char name[DUMP_NAME_LEN];
 656        int i;
 657        unsigned int part, size;
 658        unsigned long time;
 659
 660        while (&efivars->walk_entry->list != &efivars->list) {
 661                if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 662                                 vendor)) {
 663                        for (i = 0; i < DUMP_NAME_LEN; i++) {
 664                                name[i] = efivars->walk_entry->var.VariableName[i];
 665                        }
 666                        if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 667                                *id = part;
 668                                timespec->tv_sec = time;
 669                                timespec->tv_nsec = 0;
 670                                get_var_data_locked(efivars, &efivars->walk_entry->var);
 671                                size = efivars->walk_entry->var.DataSize;
 672                                *buf = kmalloc(size, GFP_KERNEL);
 673                                if (*buf == NULL)
 674                                        return -ENOMEM;
 675                                memcpy(*buf, efivars->walk_entry->var.Data,
 676                                       size);
 677                                efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 678                                                   struct efivar_entry, list);
 679                                return size;
 680                        }
 681                }
 682                efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 683                                                 struct efivar_entry, list);
 684        }
 685        return 0;
 686}
 687
 688static int efi_pstore_write(enum pstore_type_id type,
 689                enum kmsg_dump_reason reason, u64 *id,
 690                unsigned int part, size_t size, struct pstore_info *psi)
 691{
 692        char name[DUMP_NAME_LEN];
 693        char stub_name[DUMP_NAME_LEN];
 694        efi_char16_t efi_name[DUMP_NAME_LEN];
 695        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 696        struct efivars *efivars = psi->data;
 697        struct efivar_entry *entry, *found = NULL;
 698        int i, ret = 0;
 699
 700        sprintf(stub_name, "dump-type%u-%u-", type, part);
 701        sprintf(name, "%s%lu", stub_name, get_seconds());
 702
 703        spin_lock(&efivars->lock);
 704
 705        for (i = 0; i < DUMP_NAME_LEN; i++)
 706                efi_name[i] = stub_name[i];
 707
 708        /*
 709         * Clean up any entries with the same name
 710         */
 711
 712        list_for_each_entry(entry, &efivars->list, list) {
 713                get_var_data_locked(efivars, &entry->var);
 714
 715                if (efi_guidcmp(entry->var.VendorGuid, vendor))
 716                        continue;
 717                if (utf16_strncmp(entry->var.VariableName, efi_name,
 718                                  utf16_strlen(efi_name)))
 719                        continue;
 720                /* Needs to be a prefix */
 721                if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 722                        continue;
 723
 724                /* found */
 725                found = entry;
 726                efivars->ops->set_variable(entry->var.VariableName,
 727                                           &entry->var.VendorGuid,
 728                                           PSTORE_EFI_ATTRIBUTES,
 729                                           0, NULL);
 730        }
 731
 732        if (found)
 733                list_del(&found->list);
 734
 735        for (i = 0; i < DUMP_NAME_LEN; i++)
 736                efi_name[i] = name[i];
 737
 738        efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 739                                   size, psi->buf);
 740
 741        spin_unlock(&efivars->lock);
 742
 743        if (found)
 744                efivar_unregister(found);
 745
 746        if (size)
 747                ret = efivar_create_sysfs_entry(efivars,
 748                                          utf16_strsize(efi_name,
 749                                                        DUMP_NAME_LEN * 2),
 750                                          efi_name, &vendor);
 751
 752        *id = part;
 753        return ret;
 754};
 755
 756static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 757                            struct pstore_info *psi)
 758{
 759        efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
 760
 761        return 0;
 762}
 763#else
 764static int efi_pstore_open(struct pstore_info *psi)
 765{
 766        return 0;
 767}
 768
 769static int efi_pstore_close(struct pstore_info *psi)
 770{
 771        return 0;
 772}
 773
 774static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 775                               struct timespec *timespec,
 776                               char **buf, struct pstore_info *psi)
 777{
 778        return -1;
 779}
 780
 781static int efi_pstore_write(enum pstore_type_id type,
 782                enum kmsg_dump_reason reason, u64 *id,
 783                unsigned int part, size_t size, struct pstore_info *psi)
 784{
 785        return 0;
 786}
 787
 788static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 789                            struct pstore_info *psi)
 790{
 791        return 0;
 792}
 793#endif
 794
 795static struct pstore_info efi_pstore_info = {
 796        .owner          = THIS_MODULE,
 797        .name           = "efi",
 798        .open           = efi_pstore_open,
 799        .close          = efi_pstore_close,
 800        .read           = efi_pstore_read,
 801        .write          = efi_pstore_write,
 802        .erase          = efi_pstore_erase,
 803};
 804
 805static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 806                             struct bin_attribute *bin_attr,
 807                             char *buf, loff_t pos, size_t count)
 808{
 809        struct efi_variable *new_var = (struct efi_variable *)buf;
 810        struct efivars *efivars = bin_attr->private;
 811        struct efivar_entry *search_efivar, *n;
 812        unsigned long strsize1, strsize2;
 813        efi_status_t status = EFI_NOT_FOUND;
 814        int found = 0;
 815
 816        if (!capable(CAP_SYS_ADMIN))
 817                return -EACCES;
 818
 819        if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 820            validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 821                printk(KERN_ERR "efivars: Malformed variable content\n");
 822                return -EINVAL;
 823        }
 824
 825        spin_lock(&efivars->lock);
 826
 827        /*
 828         * Does this variable already exist?
 829         */
 830        list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 831                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 832                strsize2 = utf16_strsize(new_var->VariableName, 1024);
 833                if (strsize1 == strsize2 &&
 834                        !memcmp(&(search_efivar->var.VariableName),
 835                                new_var->VariableName, strsize1) &&
 836                        !efi_guidcmp(search_efivar->var.VendorGuid,
 837                                new_var->VendorGuid)) {
 838                        found = 1;
 839                        break;
 840                }
 841        }
 842        if (found) {
 843                spin_unlock(&efivars->lock);
 844                return -EINVAL;
 845        }
 846
 847        /* now *really* create the variable via EFI */
 848        status = efivars->ops->set_variable(new_var->VariableName,
 849                                            &new_var->VendorGuid,
 850                                            new_var->Attributes,
 851                                            new_var->DataSize,
 852                                            new_var->Data);
 853
 854        if (status != EFI_SUCCESS) {
 855                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 856                        status);
 857                spin_unlock(&efivars->lock);
 858                return -EIO;
 859        }
 860        spin_unlock(&efivars->lock);
 861
 862        /* Create the entry in sysfs.  Locking is not required here */
 863        status = efivar_create_sysfs_entry(efivars,
 864                                           utf16_strsize(new_var->VariableName,
 865                                                         1024),
 866                                           new_var->VariableName,
 867                                           &new_var->VendorGuid);
 868        if (status) {
 869                printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 870        }
 871        return count;
 872}
 873
 874static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 875                             struct bin_attribute *bin_attr,
 876                             char *buf, loff_t pos, size_t count)
 877{
 878        struct efi_variable *del_var = (struct efi_variable *)buf;
 879        struct efivars *efivars = bin_attr->private;
 880        struct efivar_entry *search_efivar, *n;
 881        unsigned long strsize1, strsize2;
 882        efi_status_t status = EFI_NOT_FOUND;
 883        int found = 0;
 884
 885        if (!capable(CAP_SYS_ADMIN))
 886                return -EACCES;
 887
 888        spin_lock(&efivars->lock);
 889
 890        /*
 891         * Does this variable already exist?
 892         */
 893        list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 894                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 895                strsize2 = utf16_strsize(del_var->VariableName, 1024);
 896                if (strsize1 == strsize2 &&
 897                        !memcmp(&(search_efivar->var.VariableName),
 898                                del_var->VariableName, strsize1) &&
 899                        !efi_guidcmp(search_efivar->var.VendorGuid,
 900                                del_var->VendorGuid)) {
 901                        found = 1;
 902                        break;
 903                }
 904        }
 905        if (!found) {
 906                spin_unlock(&efivars->lock);
 907                return -EINVAL;
 908        }
 909        /* force the Attributes/DataSize to 0 to ensure deletion */
 910        del_var->Attributes = 0;
 911        del_var->DataSize = 0;
 912
 913        status = efivars->ops->set_variable(del_var->VariableName,
 914                                            &del_var->VendorGuid,
 915                                            del_var->Attributes,
 916                                            del_var->DataSize,
 917                                            del_var->Data);
 918
 919        if (status != EFI_SUCCESS) {
 920                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 921                        status);
 922                spin_unlock(&efivars->lock);
 923                return -EIO;
 924        }
 925        list_del(&search_efivar->list);
 926        /* We need to release this lock before unregistering. */
 927        spin_unlock(&efivars->lock);
 928        efivar_unregister(search_efivar);
 929
 930        /* It's dead Jim.... */
 931        return count;
 932}
 933
 934/*
 935 * Let's not leave out systab information that snuck into
 936 * the efivars driver
 937 */
 938static ssize_t systab_show(struct kobject *kobj,
 939                           struct kobj_attribute *attr, char *buf)
 940{
 941        char *str = buf;
 942
 943        if (!kobj || !buf)
 944                return -EINVAL;
 945
 946        if (efi.mps != EFI_INVALID_TABLE_ADDR)
 947                str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 948        if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 949                str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 950        if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 951                str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 952        if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 953                str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 954        if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 955                str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 956        if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 957                str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 958        if (efi.uga != EFI_INVALID_TABLE_ADDR)
 959                str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 960
 961        return str - buf;
 962}
 963
 964static struct kobj_attribute efi_attr_systab =
 965                        __ATTR(systab, 0400, systab_show, NULL);
 966
 967static struct attribute *efi_subsys_attrs[] = {
 968        &efi_attr_systab.attr,
 969        NULL,   /* maybe more in the future? */
 970};
 971
 972static struct attribute_group efi_subsys_attr_group = {
 973        .attrs = efi_subsys_attrs,
 974};
 975
 976static struct kobject *efi_kobj;
 977
 978/*
 979 * efivar_create_sysfs_entry()
 980 * Requires:
 981 *    variable_name_size = number of bytes required to hold
 982 *                         variable_name (not counting the NULL
 983 *                         character at the end.
 984 *    efivars->lock is not held on entry or exit.
 985 * Returns 1 on failure, 0 on success
 986 */
 987static int
 988efivar_create_sysfs_entry(struct efivars *efivars,
 989                          unsigned long variable_name_size,
 990                          efi_char16_t *variable_name,
 991                          efi_guid_t *vendor_guid)
 992{
 993        int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 994        char *short_name;
 995        struct efivar_entry *new_efivar;
 996
 997        short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 998        new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 999
1000        if (!short_name || !new_efivar)  {
1001                kfree(short_name);
1002                kfree(new_efivar);
1003                return 1;
1004        }
1005
1006        new_efivar->efivars = efivars;
1007        memcpy(new_efivar->var.VariableName, variable_name,
1008                variable_name_size);
1009        memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1010
1011        /* Convert Unicode to normal chars (assume top bits are 0),
1012           ala UTF-8 */
1013        for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1014                short_name[i] = variable_name[i] & 0xFF;
1015        }
1016        /* This is ugly, but necessary to separate one vendor's
1017           private variables from another's.         */
1018
1019        *(short_name + strlen(short_name)) = '-';
1020        efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1021
1022        new_efivar->kobj.kset = efivars->kset;
1023        i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1024                                 "%s", short_name);
1025        if (i) {
1026                kfree(short_name);
1027                kfree(new_efivar);
1028                return 1;
1029        }
1030
1031        kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1032        kfree(short_name);
1033        short_name = NULL;
1034
1035        spin_lock(&efivars->lock);
1036        list_add(&new_efivar->list, &efivars->list);
1037        spin_unlock(&efivars->lock);
1038
1039        return 0;
1040}
1041
1042static int
1043create_efivars_bin_attributes(struct efivars *efivars)
1044{
1045        struct bin_attribute *attr;
1046        int error;
1047
1048        /* new_var */
1049        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1050        if (!attr)
1051                return -ENOMEM;
1052
1053        attr->attr.name = "new_var";
1054        attr->attr.mode = 0200;
1055        attr->write = efivar_create;
1056        attr->private = efivars;
1057        efivars->new_var = attr;
1058
1059        /* del_var */
1060        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1061        if (!attr) {
1062                error = -ENOMEM;
1063                goto out_free;
1064        }
1065        attr->attr.name = "del_var";
1066        attr->attr.mode = 0200;
1067        attr->write = efivar_delete;
1068        attr->private = efivars;
1069        efivars->del_var = attr;
1070
1071        sysfs_bin_attr_init(efivars->new_var);
1072        sysfs_bin_attr_init(efivars->del_var);
1073
1074        /* Register */
1075        error = sysfs_create_bin_file(&efivars->kset->kobj,
1076                                      efivars->new_var);
1077        if (error) {
1078                printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1079                        " due to error %d\n", error);
1080                goto out_free;
1081        }
1082        error = sysfs_create_bin_file(&efivars->kset->kobj,
1083                                      efivars->del_var);
1084        if (error) {
1085                printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1086                        " due to error %d\n", error);
1087                sysfs_remove_bin_file(&efivars->kset->kobj,
1088                                      efivars->new_var);
1089                goto out_free;
1090        }
1091
1092        return 0;
1093out_free:
1094        kfree(efivars->del_var);
1095        efivars->del_var = NULL;
1096        kfree(efivars->new_var);
1097        efivars->new_var = NULL;
1098        return error;
1099}
1100
1101void unregister_efivars(struct efivars *efivars)
1102{
1103        struct efivar_entry *entry, *n;
1104
1105        list_for_each_entry_safe(entry, n, &efivars->list, list) {
1106                spin_lock(&efivars->lock);
1107                list_del(&entry->list);
1108                spin_unlock(&efivars->lock);
1109                efivar_unregister(entry);
1110        }
1111        if (efivars->new_var)
1112                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1113        if (efivars->del_var)
1114                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1115        kfree(efivars->new_var);
1116        kfree(efivars->del_var);
1117        kset_unregister(efivars->kset);
1118}
1119EXPORT_SYMBOL_GPL(unregister_efivars);
1120
1121int register_efivars(struct efivars *efivars,
1122                     const struct efivar_operations *ops,
1123                     struct kobject *parent_kobj)
1124{
1125        efi_status_t status = EFI_NOT_FOUND;
1126        efi_guid_t vendor_guid;
1127        efi_char16_t *variable_name;
1128        unsigned long variable_name_size = 1024;
1129        int error = 0;
1130
1131        variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1132        if (!variable_name) {
1133                printk(KERN_ERR "efivars: Memory allocation failed.\n");
1134                return -ENOMEM;
1135        }
1136
1137        spin_lock_init(&efivars->lock);
1138        INIT_LIST_HEAD(&efivars->list);
1139        efivars->ops = ops;
1140
1141        efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1142        if (!efivars->kset) {
1143                printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1144                error = -ENOMEM;
1145                goto out;
1146        }
1147
1148        /*
1149         * Per EFI spec, the maximum storage allocated for both
1150         * the variable name and variable data is 1024 bytes.
1151         */
1152
1153        do {
1154                variable_name_size = 1024;
1155
1156                status = ops->get_next_variable(&variable_name_size,
1157                                                variable_name,
1158                                                &vendor_guid);
1159                switch (status) {
1160                case EFI_SUCCESS:
1161                        efivar_create_sysfs_entry(efivars,
1162                                                  variable_name_size,
1163                                                  variable_name,
1164                                                  &vendor_guid);
1165                        break;
1166                case EFI_NOT_FOUND:
1167                        break;
1168                default:
1169                        printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1170                                status);
1171                        status = EFI_NOT_FOUND;
1172                        break;
1173                }
1174        } while (status != EFI_NOT_FOUND);
1175
1176        error = create_efivars_bin_attributes(efivars);
1177        if (error)
1178                unregister_efivars(efivars);
1179
1180        efivars->efi_pstore_info = efi_pstore_info;
1181
1182        efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1183        if (efivars->efi_pstore_info.buf) {
1184                efivars->efi_pstore_info.bufsize = 1024;
1185                efivars->efi_pstore_info.data = efivars;
1186                spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1187                pstore_register(&efivars->efi_pstore_info);
1188        }
1189
1190out:
1191        kfree(variable_name);
1192
1193        return error;
1194}
1195EXPORT_SYMBOL_GPL(register_efivars);
1196
1197static struct efivars __efivars;
1198static struct efivar_operations ops;
1199
1200/*
1201 * For now we register the efi subsystem with the firmware subsystem
1202 * and the vars subsystem with the efi subsystem.  In the future, it
1203 * might make sense to split off the efi subsystem into its own
1204 * driver, but for now only efivars will register with it, so just
1205 * include it here.
1206 */
1207
1208static int __init
1209efivars_init(void)
1210{
1211        int error = 0;
1212
1213        printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1214               EFIVARS_DATE);
1215
1216        if (!efi_enabled)
1217                return 0;
1218
1219        /* For now we'll register the efi directory at /sys/firmware/efi */
1220        efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1221        if (!efi_kobj) {
1222                printk(KERN_ERR "efivars: Firmware registration failed.\n");
1223                return -ENOMEM;
1224        }
1225
1226        ops.get_variable = efi.get_variable;
1227        ops.set_variable = efi.set_variable;
1228        ops.get_next_variable = efi.get_next_variable;
1229        error = register_efivars(&__efivars, &ops, efi_kobj);
1230        if (error)
1231                goto err_put;
1232
1233        /* Don't forget the systab entry */
1234        error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1235        if (error) {
1236                printk(KERN_ERR
1237                       "efivars: Sysfs attribute export failed with error %d.\n",
1238                       error);
1239                goto err_unregister;
1240        }
1241
1242        return 0;
1243
1244err_unregister:
1245        unregister_efivars(&__efivars);
1246err_put:
1247        kobject_put(efi_kobj);
1248        return error;
1249}
1250
1251static void __exit
1252efivars_exit(void)
1253{
1254        if (efi_enabled) {
1255                unregister_efivars(&__efivars);
1256                kobject_put(efi_kobj);
1257        }
1258}
1259
1260module_init(efivars_init);
1261module_exit(efivars_exit);
1262
1263
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