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 & EFI_VARIABLE_NON_VOLATILE)
 439                str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 440        if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
 441                str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 442        if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
 443                str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 444        if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
 445                str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
 446        if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 447                str += sprintf(str,
 448                        "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
 449        if (var->Attributes &
 450                        EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
 451                str += sprintf(str,
 452                        "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
 453        if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
 454                str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
 455        return str - buf;
 456}
 457
 458static ssize_t
 459efivar_size_read(struct efivar_entry *entry, char *buf)
 460{
 461        struct efi_variable *var = &entry->var;
 462        char *str = buf;
 463        efi_status_t status;
 464
 465        if (!entry || !buf)
 466                return -EINVAL;
 467
 468        status = get_var_data(entry->efivars, var);
 469        if (status != EFI_SUCCESS)
 470                return -EIO;
 471
 472        str += sprintf(str, "0x%lx\n", var->DataSize);
 473        return str - buf;
 474}
 475
 476static ssize_t
 477efivar_data_read(struct efivar_entry *entry, char *buf)
 478{
 479        struct efi_variable *var = &entry->var;
 480        efi_status_t status;
 481
 482        if (!entry || !buf)
 483                return -EINVAL;
 484
 485        status = get_var_data(entry->efivars, var);
 486        if (status != EFI_SUCCESS)
 487                return -EIO;
 488
 489        memcpy(buf, var->Data, var->DataSize);
 490        return var->DataSize;
 491}
 492/*
 493 * We allow each variable to be edited via rewriting the
 494 * entire efi variable structure.
 495 */
 496static ssize_t
 497efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 498{
 499        struct efi_variable *new_var, *var = &entry->var;
 500        struct efivars *efivars = entry->efivars;
 501        efi_status_t status = EFI_NOT_FOUND;
 502
 503        if (count != sizeof(struct efi_variable))
 504                return -EINVAL;
 505
 506        new_var = (struct efi_variable *)buf;
 507        /*
 508         * If only updating the variable data, then the name
 509         * and guid should remain the same
 510         */
 511        if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 512                efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 513                printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 514                return -EINVAL;
 515        }
 516
 517        if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 518                printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 519                return -EINVAL;
 520        }
 521
 522        if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 523            validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 524                printk(KERN_ERR "efivars: Malformed variable content\n");
 525                return -EINVAL;
 526        }
 527
 528        spin_lock(&efivars->lock);
 529        status = efivars->ops->set_variable(new_var->VariableName,
 530                                            &new_var->VendorGuid,
 531                                            new_var->Attributes,
 532                                            new_var->DataSize,
 533                                            new_var->Data);
 534
 535        spin_unlock(&efivars->lock);
 536
 537        if (status != EFI_SUCCESS) {
 538                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 539                        status);
 540                return -EIO;
 541        }
 542
 543        memcpy(&entry->var, new_var, count);
 544        return count;
 545}
 546
 547static ssize_t
 548efivar_show_raw(struct efivar_entry *entry, char *buf)
 549{
 550        struct efi_variable *var = &entry->var;
 551        efi_status_t status;
 552
 553        if (!entry || !buf)
 554                return 0;
 555
 556        status = get_var_data(entry->efivars, var);
 557        if (status != EFI_SUCCESS)
 558                return -EIO;
 559
 560        memcpy(buf, var, sizeof(*var));
 561        return sizeof(*var);
 562}
 563
 564/*
 565 * Generic read/write functions that call the specific functions of
 566 * the attributes...
 567 */
 568static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 569                                char *buf)
 570{
 571        struct efivar_entry *var = to_efivar_entry(kobj);
 572        struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 573        ssize_t ret = -EIO;
 574
 575        if (!capable(CAP_SYS_ADMIN))
 576                return -EACCES;
 577
 578        if (efivar_attr->show) {
 579                ret = efivar_attr->show(var, buf);
 580        }
 581        return ret;
 582}
 583
 584static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 585                                const char *buf, size_t count)
 586{
 587        struct efivar_entry *var = to_efivar_entry(kobj);
 588        struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 589        ssize_t ret = -EIO;
 590
 591        if (!capable(CAP_SYS_ADMIN))
 592                return -EACCES;
 593
 594        if (efivar_attr->store)
 595                ret = efivar_attr->store(var, buf, count);
 596
 597        return ret;
 598}
 599
 600static const struct sysfs_ops efivar_attr_ops = {
 601        .show = efivar_attr_show,
 602        .store = efivar_attr_store,
 603};
 604
 605static void efivar_release(struct kobject *kobj)
 606{
 607        struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 608        kfree(var);
 609}
 610
 611static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 612static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 613static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 614static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 615static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 616
 617static struct attribute *def_attrs[] = {
 618        &efivar_attr_guid.attr,
 619        &efivar_attr_size.attr,
 620        &efivar_attr_attributes.attr,
 621        &efivar_attr_data.attr,
 622        &efivar_attr_raw_var.attr,
 623        NULL,
 624};
 625
 626static struct kobj_type efivar_ktype = {
 627        .release = efivar_release,
 628        .sysfs_ops = &efivar_attr_ops,
 629        .default_attrs = def_attrs,
 630};
 631
 632static struct pstore_info efi_pstore_info;
 633
 634static inline void
 635efivar_unregister(struct efivar_entry *var)
 636{
 637        kobject_put(&var->kobj);
 638}
 639
 640#ifdef CONFIG_PSTORE
 641
 642static int efi_pstore_open(struct pstore_info *psi)
 643{
 644        struct efivars *efivars = psi->data;
 645
 646        spin_lock(&efivars->lock);
 647        efivars->walk_entry = list_first_entry(&efivars->list,
 648                                               struct efivar_entry, list);
 649        return 0;
 650}
 651
 652static int efi_pstore_close(struct pstore_info *psi)
 653{
 654        struct efivars *efivars = psi->data;
 655
 656        spin_unlock(&efivars->lock);
 657        return 0;
 658}
 659
 660static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 661                               struct timespec *timespec,
 662                               char **buf, struct pstore_info *psi)
 663{
 664        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 665        struct efivars *efivars = psi->data;
 666        char name[DUMP_NAME_LEN];
 667        int i;
 668        unsigned int part, size;
 669        unsigned long time;
 670
 671        while (&efivars->walk_entry->list != &efivars->list) {
 672                if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 673                                 vendor)) {
 674                        for (i = 0; i < DUMP_NAME_LEN; i++) {
 675                                name[i] = efivars->walk_entry->var.VariableName[i];
 676                        }
 677                        if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 678                                *id = part;
 679                                timespec->tv_sec = time;
 680                                timespec->tv_nsec = 0;
 681                                get_var_data_locked(efivars, &efivars->walk_entry->var);
 682                                size = efivars->walk_entry->var.DataSize;
 683                                *buf = kmalloc(size, GFP_KERNEL);
 684                                if (*buf == NULL)
 685                                        return -ENOMEM;
 686                                memcpy(*buf, efivars->walk_entry->var.Data,
 687                                       size);
 688                                efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 689                                                   struct efivar_entry, list);
 690                                return size;
 691                        }
 692                }
 693                efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 694                                                 struct efivar_entry, list);
 695        }
 696        return 0;
 697}
 698
 699static int efi_pstore_write(enum pstore_type_id type,
 700                enum kmsg_dump_reason reason, u64 *id,
 701                unsigned int part, size_t size, struct pstore_info *psi)
 702{
 703        char name[DUMP_NAME_LEN];
 704        char stub_name[DUMP_NAME_LEN];
 705        efi_char16_t efi_name[DUMP_NAME_LEN];
 706        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 707        struct efivars *efivars = psi->data;
 708        struct efivar_entry *entry, *found = NULL;
 709        int i, ret = 0;
 710
 711        sprintf(stub_name, "dump-type%u-%u-", type, part);
 712        sprintf(name, "%s%lu", stub_name, get_seconds());
 713
 714        spin_lock(&efivars->lock);
 715
 716        for (i = 0; i < DUMP_NAME_LEN; i++)
 717                efi_name[i] = stub_name[i];
 718
 719        /*
 720         * Clean up any entries with the same name
 721         */
 722
 723        list_for_each_entry(entry, &efivars->list, list) {
 724                get_var_data_locked(efivars, &entry->var);
 725
 726                if (efi_guidcmp(entry->var.VendorGuid, vendor))
 727                        continue;
 728                if (utf16_strncmp(entry->var.VariableName, efi_name,
 729                                  utf16_strlen(efi_name)))
 730                        continue;
 731                /* Needs to be a prefix */
 732                if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 733                        continue;
 734
 735                /* found */
 736                found = entry;
 737                efivars->ops->set_variable(entry->var.VariableName,
 738                                           &entry->var.VendorGuid,
 739                                           PSTORE_EFI_ATTRIBUTES,
 740                                           0, NULL);
 741        }
 742
 743        if (found)
 744                list_del(&found->list);
 745
 746        for (i = 0; i < DUMP_NAME_LEN; i++)
 747                efi_name[i] = name[i];
 748
 749        efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 750                                   size, psi->buf);
 751
 752        spin_unlock(&efivars->lock);
 753
 754        if (found)
 755                efivar_unregister(found);
 756
 757        if (size)
 758                ret = efivar_create_sysfs_entry(efivars,
 759                                          utf16_strsize(efi_name,
 760                                                        DUMP_NAME_LEN * 2),
 761                                          efi_name, &vendor);
 762
 763        *id = part;
 764        return ret;
 765};
 766
 767static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 768                            struct pstore_info *psi)
 769{
 770        efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
 771
 772        return 0;
 773}
 774#else
 775static int efi_pstore_open(struct pstore_info *psi)
 776{
 777        return 0;
 778}
 779
 780static int efi_pstore_close(struct pstore_info *psi)
 781{
 782        return 0;
 783}
 784
 785static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 786                               struct timespec *timespec,
 787                               char **buf, struct pstore_info *psi)
 788{
 789        return -1;
 790}
 791
 792static int efi_pstore_write(enum pstore_type_id type,
 793                enum kmsg_dump_reason reason, u64 *id,
 794                unsigned int part, size_t size, struct pstore_info *psi)
 795{
 796        return 0;
 797}
 798
 799static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 800                            struct pstore_info *psi)
 801{
 802        return 0;
 803}
 804#endif
 805
 806static struct pstore_info efi_pstore_info = {
 807        .owner          = THIS_MODULE,
 808        .name           = "efi",
 809        .open           = efi_pstore_open,
 810        .close          = efi_pstore_close,
 811        .read           = efi_pstore_read,
 812        .write          = efi_pstore_write,
 813        .erase          = efi_pstore_erase,
 814};
 815
 816static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 817                             struct bin_attribute *bin_attr,
 818                             char *buf, loff_t pos, size_t count)
 819{
 820        struct efi_variable *new_var = (struct efi_variable *)buf;
 821        struct efivars *efivars = bin_attr->private;
 822        struct efivar_entry *search_efivar, *n;
 823        unsigned long strsize1, strsize2;
 824        efi_status_t status = EFI_NOT_FOUND;
 825        int found = 0;
 826
 827        if (!capable(CAP_SYS_ADMIN))
 828                return -EACCES;
 829
 830        if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
 831            validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
 832                printk(KERN_ERR "efivars: Malformed variable content\n");
 833                return -EINVAL;
 834        }
 835
 836        spin_lock(&efivars->lock);
 837
 838        /*
 839         * Does this variable already exist?
 840         */
 841        list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 842                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 843                strsize2 = utf16_strsize(new_var->VariableName, 1024);
 844                if (strsize1 == strsize2 &&
 845                        !memcmp(&(search_efivar->var.VariableName),
 846                                new_var->VariableName, strsize1) &&
 847                        !efi_guidcmp(search_efivar->var.VendorGuid,
 848                                new_var->VendorGuid)) {
 849                        found = 1;
 850                        break;
 851                }
 852        }
 853        if (found) {
 854                spin_unlock(&efivars->lock);
 855                return -EINVAL;
 856        }
 857
 858        /* now *really* create the variable via EFI */
 859        status = efivars->ops->set_variable(new_var->VariableName,
 860                                            &new_var->VendorGuid,
 861                                            new_var->Attributes,
 862                                            new_var->DataSize,
 863                                            new_var->Data);
 864
 865        if (status != EFI_SUCCESS) {
 866                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 867                        status);
 868                spin_unlock(&efivars->lock);
 869                return -EIO;
 870        }
 871        spin_unlock(&efivars->lock);
 872
 873        /* Create the entry in sysfs.  Locking is not required here */
 874        status = efivar_create_sysfs_entry(efivars,
 875                                           utf16_strsize(new_var->VariableName,
 876                                                         1024),
 877                                           new_var->VariableName,
 878                                           &new_var->VendorGuid);
 879        if (status) {
 880                printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 881        }
 882        return count;
 883}
 884
 885static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 886                             struct bin_attribute *bin_attr,
 887                             char *buf, loff_t pos, size_t count)
 888{
 889        struct efi_variable *del_var = (struct efi_variable *)buf;
 890        struct efivars *efivars = bin_attr->private;
 891        struct efivar_entry *search_efivar, *n;
 892        unsigned long strsize1, strsize2;
 893        efi_status_t status = EFI_NOT_FOUND;
 894        int found = 0;
 895
 896        if (!capable(CAP_SYS_ADMIN))
 897                return -EACCES;
 898
 899        spin_lock(&efivars->lock);
 900
 901        /*
 902         * Does this variable already exist?
 903         */
 904        list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 905                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 906                strsize2 = utf16_strsize(del_var->VariableName, 1024);
 907                if (strsize1 == strsize2 &&
 908                        !memcmp(&(search_efivar->var.VariableName),
 909                                del_var->VariableName, strsize1) &&
 910                        !efi_guidcmp(search_efivar->var.VendorGuid,
 911                                del_var->VendorGuid)) {
 912                        found = 1;
 913                        break;
 914                }
 915        }
 916        if (!found) {
 917                spin_unlock(&efivars->lock);
 918                return -EINVAL;
 919        }
 920        /* force the Attributes/DataSize to 0 to ensure deletion */
 921        del_var->Attributes = 0;
 922        del_var->DataSize = 0;
 923
 924        status = efivars->ops->set_variable(del_var->VariableName,
 925                                            &del_var->VendorGuid,
 926                                            del_var->Attributes,
 927                                            del_var->DataSize,
 928                                            del_var->Data);
 929
 930        if (status != EFI_SUCCESS) {
 931                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 932                        status);
 933                spin_unlock(&efivars->lock);
 934                return -EIO;
 935        }
 936        list_del(&search_efivar->list);
 937        /* We need to release this lock before unregistering. */
 938        spin_unlock(&efivars->lock);
 939        efivar_unregister(search_efivar);
 940
 941        /* It's dead Jim.... */
 942        return count;
 943}
 944
 945/*
 946 * Let's not leave out systab information that snuck into
 947 * the efivars driver
 948 */
 949static ssize_t systab_show(struct kobject *kobj,
 950                           struct kobj_attribute *attr, char *buf)
 951{
 952        char *str = buf;
 953
 954        if (!kobj || !buf)
 955                return -EINVAL;
 956
 957        if (efi.mps != EFI_INVALID_TABLE_ADDR)
 958                str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 959        if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 960                str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 961        if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 962                str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 963        if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 964                str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 965        if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 966                str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 967        if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 968                str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 969        if (efi.uga != EFI_INVALID_TABLE_ADDR)
 970                str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 971
 972        return str - buf;
 973}
 974
 975static struct kobj_attribute efi_attr_systab =
 976                        __ATTR(systab, 0400, systab_show, NULL);
 977
 978static struct attribute *efi_subsys_attrs[] = {
 979        &efi_attr_systab.attr,
 980        NULL,   /* maybe more in the future? */
 981};
 982
 983static struct attribute_group efi_subsys_attr_group = {
 984        .attrs = efi_subsys_attrs,
 985};
 986
 987static struct kobject *efi_kobj;
 988
 989/*
 990 * efivar_create_sysfs_entry()
 991 * Requires:
 992 *    variable_name_size = number of bytes required to hold
 993 *                         variable_name (not counting the NULL
 994 *                         character at the end.
 995 *    efivars->lock is not held on entry or exit.
 996 * Returns 1 on failure, 0 on success
 997 */
 998static int
 999efivar_create_sysfs_entry(struct efivars *efivars,
1000                          unsigned long variable_name_size,
1001                          efi_char16_t *variable_name,
1002                          efi_guid_t *vendor_guid)
1003{
1004        int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1005        char *short_name;
1006        struct efivar_entry *new_efivar;
1007
1008        short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1009        new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1010
1011        if (!short_name || !new_efivar)  {
1012                kfree(short_name);
1013                kfree(new_efivar);
1014                return 1;
1015        }
1016
1017        new_efivar->efivars = efivars;
1018        memcpy(new_efivar->var.VariableName, variable_name,
1019                variable_name_size);
1020        memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1021
1022        /* Convert Unicode to normal chars (assume top bits are 0),
1023           ala UTF-8 */
1024        for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1025                short_name[i] = variable_name[i] & 0xFF;
1026        }
1027        /* This is ugly, but necessary to separate one vendor's
1028           private variables from another's.         */
1029
1030        *(short_name + strlen(short_name)) = '-';
1031        efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1032
1033        new_efivar->kobj.kset = efivars->kset;
1034        i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1035                                 "%s", short_name);
1036        if (i) {
1037                kfree(short_name);
1038                kfree(new_efivar);
1039                return 1;
1040        }
1041
1042        kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1043        kfree(short_name);
1044        short_name = NULL;
1045
1046        spin_lock(&efivars->lock);
1047        list_add(&new_efivar->list, &efivars->list);
1048        spin_unlock(&efivars->lock);
1049
1050        return 0;
1051}
1052
1053static int
1054create_efivars_bin_attributes(struct efivars *efivars)
1055{
1056        struct bin_attribute *attr;
1057        int error;
1058
1059        /* new_var */
1060        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1061        if (!attr)
1062                return -ENOMEM;
1063
1064        attr->attr.name = "new_var";
1065        attr->attr.mode = 0200;
1066        attr->write = efivar_create;
1067        attr->private = efivars;
1068        efivars->new_var = attr;
1069
1070        /* del_var */
1071        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1072        if (!attr) {
1073                error = -ENOMEM;
1074                goto out_free;
1075        }
1076        attr->attr.name = "del_var";
1077        attr->attr.mode = 0200;
1078        attr->write = efivar_delete;
1079        attr->private = efivars;
1080        efivars->del_var = attr;
1081
1082        sysfs_bin_attr_init(efivars->new_var);
1083        sysfs_bin_attr_init(efivars->del_var);
1084
1085        /* Register */
1086        error = sysfs_create_bin_file(&efivars->kset->kobj,
1087                                      efivars->new_var);
1088        if (error) {
1089                printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1090                        " due to error %d\n", error);
1091                goto out_free;
1092        }
1093        error = sysfs_create_bin_file(&efivars->kset->kobj,
1094                                      efivars->del_var);
1095        if (error) {
1096                printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1097                        " due to error %d\n", error);
1098                sysfs_remove_bin_file(&efivars->kset->kobj,
1099                                      efivars->new_var);
1100                goto out_free;
1101        }
1102
1103        return 0;
1104out_free:
1105        kfree(efivars->del_var);
1106        efivars->del_var = NULL;
1107        kfree(efivars->new_var);
1108        efivars->new_var = NULL;
1109        return error;
1110}
1111
1112void unregister_efivars(struct efivars *efivars)
1113{
1114        struct efivar_entry *entry, *n;
1115
1116        list_for_each_entry_safe(entry, n, &efivars->list, list) {
1117                spin_lock(&efivars->lock);
1118                list_del(&entry->list);
1119                spin_unlock(&efivars->lock);
1120                efivar_unregister(entry);
1121        }
1122        if (efivars->new_var)
1123                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1124        if (efivars->del_var)
1125                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1126        kfree(efivars->new_var);
1127        kfree(efivars->del_var);
1128        kset_unregister(efivars->kset);
1129}
1130EXPORT_SYMBOL_GPL(unregister_efivars);
1131
1132int register_efivars(struct efivars *efivars,
1133                     const struct efivar_operations *ops,
1134                     struct kobject *parent_kobj)
1135{
1136        efi_status_t status = EFI_NOT_FOUND;
1137        efi_guid_t vendor_guid;
1138        efi_char16_t *variable_name;
1139        unsigned long variable_name_size = 1024;
1140        int error = 0;
1141
1142        variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1143        if (!variable_name) {
1144                printk(KERN_ERR "efivars: Memory allocation failed.\n");
1145                return -ENOMEM;
1146        }
1147
1148        spin_lock_init(&efivars->lock);
1149        INIT_LIST_HEAD(&efivars->list);
1150        efivars->ops = ops;
1151
1152        efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1153        if (!efivars->kset) {
1154                printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1155                error = -ENOMEM;
1156                goto out;
1157        }
1158
1159        /*
1160         * Per EFI spec, the maximum storage allocated for both
1161         * the variable name and variable data is 1024 bytes.
1162         */
1163
1164        do {
1165                variable_name_size = 1024;
1166
1167                status = ops->get_next_variable(&variable_name_size,
1168                                                variable_name,
1169                                                &vendor_guid);
1170                switch (status) {
1171                case EFI_SUCCESS:
1172                        efivar_create_sysfs_entry(efivars,
1173                                                  variable_name_size,
1174                                                  variable_name,
1175                                                  &vendor_guid);
1176                        break;
1177                case EFI_NOT_FOUND:
1178                        break;
1179                default:
1180                        printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1181                                status);
1182                        status = EFI_NOT_FOUND;
1183                        break;
1184                }
1185        } while (status != EFI_NOT_FOUND);
1186
1187        error = create_efivars_bin_attributes(efivars);
1188        if (error)
1189                unregister_efivars(efivars);
1190
1191        efivars->efi_pstore_info = efi_pstore_info;
1192
1193        efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1194        if (efivars->efi_pstore_info.buf) {
1195                efivars->efi_pstore_info.bufsize = 1024;
1196                efivars->efi_pstore_info.data = efivars;
1197                spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1198                pstore_register(&efivars->efi_pstore_info);
1199        }
1200
1201out:
1202        kfree(variable_name);
1203
1204        return error;
1205}
1206EXPORT_SYMBOL_GPL(register_efivars);
1207
1208static struct efivars __efivars;
1209static struct efivar_operations ops;
1210
1211/*
1212 * For now we register the efi subsystem with the firmware subsystem
1213 * and the vars subsystem with the efi subsystem.  In the future, it
1214 * might make sense to split off the efi subsystem into its own
1215 * driver, but for now only efivars will register with it, so just
1216 * include it here.
1217 */
1218
1219static int __init
1220efivars_init(void)
1221{
1222        int error = 0;
1223
1224        printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1225               EFIVARS_DATE);
1226
1227        if (!efi_enabled)
1228                return 0;
1229
1230        /* For now we'll register the efi directory at /sys/firmware/efi */
1231        efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1232        if (!efi_kobj) {
1233                printk(KERN_ERR "efivars: Firmware registration failed.\n");
1234                return -ENOMEM;
1235        }
1236
1237        ops.get_variable = efi.get_variable;
1238        ops.set_variable = efi.set_variable;
1239        ops.get_next_variable = efi.get_next_variable;
1240        error = register_efivars(&__efivars, &ops, efi_kobj);
1241        if (error)
1242                goto err_put;
1243
1244        /* Don't forget the systab entry */
1245        error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1246        if (error) {
1247                printk(KERN_ERR
1248                       "efivars: Sysfs attribute export failed with error %d.\n",
1249                       error);
1250                goto err_unregister;
1251        }
1252
1253        return 0;
1254
1255err_unregister:
1256        unregister_efivars(&__efivars);
1257err_put:
1258        kobject_put(efi_kobj);
1259        return error;
1260}
1261
1262static void __exit
1263efivars_exit(void)
1264{
1265        if (efi_enabled) {
1266                unregister_efivars(&__efivars);
1267                kobject_put(efi_kobj);
1268        }
1269}
1270
1271module_init(efivars_init);
1272module_exit(efivars_exit);
1273
1274
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