drivers/firmware/efivars.c

   1 /*
   2  * EFI Variables - efivars.c
   3  *
   4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
   5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
   6  *
   7  * This code takes all variables accessible from EFI runtime and
   8  *  exports them via sysfs
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  * Changelog:
  25  *
  26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
  27  *   remove check for efi_enabled in exit
  28  *   add MODULE_VERSION
  29  *
  30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
  31  *   minor bug fixes
  32  *
  33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
  34  *   converted driver to export variable information via sysfs
  35  *   and moved to drivers/firmware directory
  36  *   bumped revision number to v0.07 to reflect conversion & move
  37  *
  38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
  39  *   fix locking per Peter Chubb's findings
  40  *
  41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
  42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
  43  *
  44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
  45  *   use list_for_each_safe when deleting vars.
  46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
  47  *   v0.04 release to linux-ia64@linuxia64.org
  48  *
  49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
  50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
  51  *   efi.c own the /proc/efi directory.
  52  *   v0.03 release to linux-ia64@linuxia64.org
  53  *
  54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  55  *   At the request of Stephane, moved ownership of /proc/efi
  56  *   to efi.c, and now efivars lives under /proc/efi/vars.
  57  *
  58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
  59  *   Feedback received from Stephane Eranian incorporated.
  60  *   efivar_write() checks copy_from_user() return value.
  61  *   efivar_read/write() returns proper errno.
  62  *   v0.02 release to linux-ia64@linuxia64.org
  63  *
  64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
  65  *   v0.01 release to linux-ia64@linuxia64.org
  66  */
  67
  68 #include <linux/capability.h>
  69 #include <linux/types.h>
  70 #include <linux/errno.h>
  71 #include <linux/init.h>
  72 #include <linux/mm.h>
  73 #include <linux/module.h>
  74 #include <linux/string.h>
  75 #include <linux/smp.h>
  76 #include <linux/efi.h>
  77 #include <linux/sysfs.h>
  78 #include <linux/kobject.h>
  79 #include <linux/device.h>
  80 #include <linux/slab.h>
  81 #include <linux/pstore.h>
  82
  83 #include <asm/uaccess.h>
  84
  85 #define EFIVARS_VERSION "0.08"
  86 #define EFIVARS_DATE "2004-May-17"
  87
  88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
  89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
  90 MODULE_LICENSE("GPL");
  91 MODULE_VERSION(EFIVARS_VERSION);
  92
  93 #define DUMP_NAME_LEN 52
  94
  95 /*
  96  * The maximum size of VariableName + Data = 1024
  97  * Therefore, it's reasonable to save that much
  98  * space in each part of the structure,
  99  * and we use a page for reading/writing.
 100  */
 101
 102 struct efi_variable {
 103         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
 104         efi_guid_t    VendorGuid;
 105         unsigned long DataSize;
 106         __u8          Data[1024];
 107         efi_status_t  Status;
 108         __u32         Attributes;
 109 } __attribute__((packed));
 110
 111
 112 struct efivar_entry {
 113         struct efivars *efivars;
 114         struct efi_variable var;
 115         struct list_head list;
 116         struct kobject kobj;
 117 };
 118
 119 struct efivar_attribute {
 120         struct attribute attr;
 121         ssize_t (*show) (struct efivar_entry *entry, char *buf);
 122         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 123 };
 124
 125 #define PSTORE_EFI_ATTRIBUTES \
 126         (EFI_VARIABLE_NON_VOLATILE | \
 127          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
 128          EFI_VARIABLE_RUNTIME_ACCESS)
 129
 130 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 131 struct efivar_attribute efivar_attr_##_name = { \
 132         .attr = {.name = __stringify(_name), .mode = _mode}, \
 133         .show = _show, \
 134         .store = _store, \
 135 };
 136
 137 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
 138 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
 139
 140 /*
 141  * Prototype for sysfs creation function
 142  */
 143 static int
 144 efivar_create_sysfs_entry(struct efivars *efivars,
 145                           unsigned long variable_name_size,
 146                           efi_char16_t *variable_name,
 147                           efi_guid_t *vendor_guid);
 148
 149 /* Return the number of unicode characters in data */
 150 static unsigned long
 151 utf16_strnlen(efi_char16_t *s, size_t maxlength)
 152 {
 153         unsigned long length = 0;
 154
 155         while (*s++ != 0 && length < maxlength)
 156                 length++;
 157         return length;
 158 }
 159
 160 static inline unsigned long
 161 utf16_strlen(efi_char16_t *s)
 162 {
 163         return utf16_strnlen(s, ~0UL);
 164 }
 165
 166 /*
 167  * Return the number of bytes is the length of this string
 168  * Note: this is NOT the same as the number of unicode characters
 169  */
 170 static inline unsigned long
 171 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 172 {
 173         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 174 }
 175
 176 static inline int
 177 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
 178 {
 179         while (1) {
 180                 if (len == 0)
 181                         return 0;
 182                 if (*a < *b)
 183                         return -1;
 184                 if (*a > *b)
 185                         return 1;
 186                 if (*a == 0) /* implies *b == 0 */
 187                         return 0;
 188                 a++;
 189                 b++;
 190                 len--;
 191         }
 192 }
 193
 194 static efi_status_t
 195 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 196 {
 197         efi_status_t status;
 198
 199         var->DataSize = 1024;
 200         status = efivars->ops->get_variable(var->VariableName,
 201                                             &var->VendorGuid,
 202                                             &var->Attributes,
 203                                             &var->DataSize,
 204                                             var->Data);
 205         return status;
 206 }
 207
 208 static efi_status_t
 209 get_var_data(struct efivars *efivars, struct efi_variable *var)
 210 {
 211         efi_status_t status;
 212
 213         spin_lock(&efivars->lock);
 214         status = get_var_data_locked(efivars, var);
 215         spin_unlock(&efivars->lock);
 216
 217         if (status != EFI_SUCCESS) {
 218                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 219                         status);
 220         }
 221         return status;
 222 }
 223
 224 static ssize_t
 225 efivar_guid_read(struct efivar_entry *entry, char *buf)
 226 {
 227         struct efi_variable *var = &entry->var;
 228         char *str = buf;
 229
 230         if (!entry || !buf)
 231                 return 0;
 232
 233         efi_guid_unparse(&var->VendorGuid, str);
 234         str += strlen(str);
 235         str += sprintf(str, "\n");
 236
 237         return str - buf;
 238 }
 239
 240 static ssize_t
 241 efivar_attr_read(struct efivar_entry *entry, char *buf)
 242 {
 243         struct efi_variable *var = &entry->var;
 244         char *str = buf;
 245         efi_status_t status;
 246
 247         if (!entry || !buf)
 248                 return -EINVAL;
 249
 250         status = get_var_data(entry->efivars, var);
 251         if (status != EFI_SUCCESS)
 252                 return -EIO;
 253
 254         if (var->Attributes & 0x1)
 255                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
 256         if (var->Attributes & 0x2)
 257                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
 258         if (var->Attributes & 0x4)
 259                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
 260         return str - buf;
 261 }
 262
 263 static ssize_t
 264 efivar_size_read(struct efivar_entry *entry, char *buf)
 265 {
 266         struct efi_variable *var = &entry->var;
 267         char *str = buf;
 268         efi_status_t status;
 269
 270         if (!entry || !buf)
 271                 return -EINVAL;
 272
 273         status = get_var_data(entry->efivars, var);
 274         if (status != EFI_SUCCESS)
 275                 return -EIO;
 276
 277         str += sprintf(str, "0x%lx\n", var->DataSize);
 278         return str - buf;
 279 }
 280
 281 static ssize_t
 282 efivar_data_read(struct efivar_entry *entry, char *buf)
 283 {
 284         struct efi_variable *var = &entry->var;
 285         efi_status_t status;
 286
 287         if (!entry || !buf)
 288                 return -EINVAL;
 289
 290         status = get_var_data(entry->efivars, var);
 291         if (status != EFI_SUCCESS)
 292                 return -EIO;
 293
 294         memcpy(buf, var->Data, var->DataSize);
 295         return var->DataSize;
 296 }
 297 /*
 298  * We allow each variable to be edited via rewriting the
 299  * entire efi variable structure.
 300  */
 301 static ssize_t
 302 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
 303 {
 304         struct efi_variable *new_var, *var = &entry->var;
 305         struct efivars *efivars = entry->efivars;
 306         efi_status_t status = EFI_NOT_FOUND;
 307
 308         if (count != sizeof(struct efi_variable))
 309                 return -EINVAL;
 310
 311         new_var = (struct efi_variable *)buf;
 312         /*
 313          * If only updating the variable data, then the name
 314          * and guid should remain the same
 315          */
 316         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
 317                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
 318                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
 319                 return -EINVAL;
 320         }
 321
 322         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
 323                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
 324                 return -EINVAL;
 325         }
 326
 327         spin_lock(&efivars->lock);
 328         status = efivars->ops->set_variable(new_var->VariableName,
 329                                             &new_var->VendorGuid,
 330                                             new_var->Attributes,
 331                                             new_var->DataSize,
 332                                             new_var->Data);
 333
 334         spin_unlock(&efivars->lock);
 335
 336         if (status != EFI_SUCCESS) {
 337                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 338                         status);
 339                 return -EIO;
 340         }
 341
 342         memcpy(&entry->var, new_var, count);
 343         return count;
 344 }
 345
 346 static ssize_t
 347 efivar_show_raw(struct efivar_entry *entry, char *buf)
 348 {
 349         struct efi_variable *var = &entry->var;
 350         efi_status_t status;
 351
 352         if (!entry || !buf)
 353                 return 0;
 354
 355         status = get_var_data(entry->efivars, var);
 356         if (status != EFI_SUCCESS)
 357                 return -EIO;
 358
 359         memcpy(buf, var, sizeof(*var));
 360         return sizeof(*var);
 361 }
 362
 363 /*
 364  * Generic read/write functions that call the specific functions of
 365  * the attributes...
 366  */
 367 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
 368                                 char *buf)
 369 {
 370         struct efivar_entry *var = to_efivar_entry(kobj);
 371         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 372         ssize_t ret = -EIO;
 373
 374         if (!capable(CAP_SYS_ADMIN))
 375                 return -EACCES;
 376
 377         if (efivar_attr->show) {
 378                 ret = efivar_attr->show(var, buf);
 379         }
 380         return ret;
 381 }
 382
 383 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
 384                                 const char *buf, size_t count)
 385 {
 386         struct efivar_entry *var = to_efivar_entry(kobj);
 387         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
 388         ssize_t ret = -EIO;
 389
 390         if (!capable(CAP_SYS_ADMIN))
 391                 return -EACCES;
 392
 393         if (efivar_attr->store)
 394                 ret = efivar_attr->store(var, buf, count);
 395
 396         return ret;
 397 }
 398
 399 static const struct sysfs_ops efivar_attr_ops = {
 400         .show = efivar_attr_show,
 401         .store = efivar_attr_store,
 402 };
 403
 404 static void efivar_release(struct kobject *kobj)
 405 {
 406         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
 407         kfree(var);
 408 }
 409
 410 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
 411 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
 412 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
 413 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
 414 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
 415
 416 static struct attribute *def_attrs[] = {
 417         &efivar_attr_guid.attr,
 418         &efivar_attr_size.attr,
 419         &efivar_attr_attributes.attr,
 420         &efivar_attr_data.attr,
 421         &efivar_attr_raw_var.attr,
 422         NULL,
 423 };
 424
 425 static struct kobj_type efivar_ktype = {
 426         .release = efivar_release,
 427         .sysfs_ops = &efivar_attr_ops,
 428         .default_attrs = def_attrs,
 429 };
 430
 431 static struct pstore_info efi_pstore_info;
 432
 433 static inline void
 434 efivar_unregister(struct efivar_entry *var)
 435 {
 436         kobject_put(&var->kobj);
 437 }
 438
 439 #ifdef CONFIG_PSTORE
 440
 441 static int efi_pstore_open(struct pstore_info *psi)
 442 {
 443         struct efivars *efivars = psi->data;
 444
 445         spin_lock(&efivars->lock);
 446         efivars->walk_entry = list_first_entry(&efivars->list,
 447                                                struct efivar_entry, list);
 448         return 0;
 449 }
 450
 451 static int efi_pstore_close(struct pstore_info *psi)
 452 {
 453         struct efivars *efivars = psi->data;
 454
 455         spin_unlock(&efivars->lock);
 456         return 0;
 457 }
 458
 459 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 460                                struct timespec *timespec,
 461                                char **buf, struct pstore_info *psi)
 462 {
 463         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 464         struct efivars *efivars = psi->data;
 465         char name[DUMP_NAME_LEN];
 466         int i;
 467         unsigned int part, size;
 468         unsigned long time;
 469
 470         while (&efivars->walk_entry->list != &efivars->list) {
 471                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
 472                                  vendor)) {
 473                         for (i = 0; i < DUMP_NAME_LEN; i++) {
 474                                 name[i] = efivars->walk_entry->var.VariableName[i];
 475                         }
 476                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
 477                                 *id = part;
 478                                 timespec->tv_sec = time;
 479                                 timespec->tv_nsec = 0;
 480                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
 481                                 size = efivars->walk_entry->var.DataSize;
 482                                 *buf = kmalloc(size, GFP_KERNEL);
 483                                 if (*buf == NULL)
 484                                         return -ENOMEM;
 485                                 memcpy(*buf, efivars->walk_entry->var.Data,
 486                                        size);
 487                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 488                                                    struct efivar_entry, list);
 489                                 return size;
 490                         }
 491                 }
 492                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 493                                                  struct efivar_entry, list);
 494         }
 495         return 0;
 496 }
 497
 498 static int efi_pstore_write(enum pstore_type_id type,
 499                 enum kmsg_dump_reason reason, u64 *id,
 500                 unsigned int part, size_t size, struct pstore_info *psi)
 501 {
 502         char name[DUMP_NAME_LEN];
 503         char stub_name[DUMP_NAME_LEN];
 504         efi_char16_t efi_name[DUMP_NAME_LEN];
 505         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 506         struct efivars *efivars = psi->data;
 507         struct efivar_entry *entry, *found = NULL;
 508         int i, ret = 0;
 509
 510         sprintf(stub_name, "dump-type%u-%u-", type, part);
 511         sprintf(name, "%s%lu", stub_name, get_seconds());
 512
 513         spin_lock(&efivars->lock);
 514
 515         for (i = 0; i < DUMP_NAME_LEN; i++)
 516                 efi_name[i] = stub_name[i];
 517
 518         /*
 519          * Clean up any entries with the same name
 520          */
 521
 522         list_for_each_entry(entry, &efivars->list, list) {
 523                 get_var_data_locked(efivars, &entry->var);
 524
 525                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
 526                         continue;
 527                 if (utf16_strncmp(entry->var.VariableName, efi_name,
 528                                   utf16_strlen(efi_name)))
 529                         continue;
 530                 /* Needs to be a prefix */
 531                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
 532                         continue;
 533
 534                 /* found */
 535                 found = entry;
 536                 efivars->ops->set_variable(entry->var.VariableName,
 537                                            &entry->var.VendorGuid,
 538                                            PSTORE_EFI_ATTRIBUTES,
 539                                            0, NULL);
 540         }
 541
 542         if (found)
 543                 list_del(&found->list);
 544
 545         for (i = 0; i < DUMP_NAME_LEN; i++)
 546                 efi_name[i] = name[i];
 547
 548         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 549                                    size, psi->buf);
 550
 551         spin_unlock(&efivars->lock);
 552
 553         if (found)
 554                 efivar_unregister(found);
 555
 556         if (size)
 557                 ret = efivar_create_sysfs_entry(efivars,
 558                                           utf16_strsize(efi_name,
 559                                                         DUMP_NAME_LEN * 2),
 560                                           efi_name, &vendor);
 561
 562         *id = part;
 563         return ret;
 564 };
 565
 566 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 567                             struct pstore_info *psi)
 568 {
 569         efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
 570
 571         return 0;
 572 }
 573 #else
 574 static int efi_pstore_open(struct pstore_info *psi)
 575 {
 576         return 0;
 577 }
 578
 579 static int efi_pstore_close(struct pstore_info *psi)
 580 {
 581         return 0;
 582 }
 583
 584 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 585                                struct timespec *timespec,
 586                                char **buf, struct pstore_info *psi)
 587 {
 588         return -1;
 589 }
 590
 591 static int efi_pstore_write(enum pstore_type_id type,
 592                 enum kmsg_dump_reason reason, u64 *id,
 593                 unsigned int part, size_t size, struct pstore_info *psi)
 594 {
 595         return 0;
 596 }
 597
 598 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 599                             struct pstore_info *psi)
 600 {
 601         return 0;
 602 }
 603 #endif
 604
 605 static struct pstore_info efi_pstore_info = {
 606         .owner          = THIS_MODULE,
 607         .name           = "efi",
 608         .open           = efi_pstore_open,
 609         .close          = efi_pstore_close,
 610         .read           = efi_pstore_read,
 611         .write          = efi_pstore_write,
 612         .erase          = efi_pstore_erase,
 613 };
 614
 615 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 616                              struct bin_attribute *bin_attr,
 617                              char *buf, loff_t pos, size_t count)
 618 {
 619         struct efi_variable *new_var = (struct efi_variable *)buf;
 620         struct efivars *efivars = bin_attr->private;
 621         struct efivar_entry *search_efivar, *n;
 622         unsigned long strsize1, strsize2;
 623         efi_status_t status = EFI_NOT_FOUND;
 624         int found = 0;
 625
 626         if (!capable(CAP_SYS_ADMIN))
 627                 return -EACCES;
 628
 629         spin_lock(&efivars->lock);
 630
 631         /*
 632          * Does this variable already exist?
 633          */
 634         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 635                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 636                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
 637                 if (strsize1 == strsize2 &&
 638                         !memcmp(&(search_efivar->var.VariableName),
 639                                 new_var->VariableName, strsize1) &&
 640                         !efi_guidcmp(search_efivar->var.VendorGuid,
 641                                 new_var->VendorGuid)) {
 642                         found = 1;
 643                         break;
 644                 }
 645         }
 646         if (found) {
 647                 spin_unlock(&efivars->lock);
 648                 return -EINVAL;
 649         }
 650
 651         /* now *really* create the variable via EFI */
 652         status = efivars->ops->set_variable(new_var->VariableName,
 653                                             &new_var->VendorGuid,
 654                                             new_var->Attributes,
 655                                             new_var->DataSize,
 656                                             new_var->Data);
 657
 658         if (status != EFI_SUCCESS) {
 659                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 660                         status);
 661                 spin_unlock(&efivars->lock);
 662                 return -EIO;
 663         }
 664         spin_unlock(&efivars->lock);
 665
 666         /* Create the entry in sysfs.  Locking is not required here */
 667         status = efivar_create_sysfs_entry(efivars,
 668                                            utf16_strsize(new_var->VariableName,
 669                                                          1024),
 670                                            new_var->VariableName,
 671                                            &new_var->VendorGuid);
 672         if (status) {
 673                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
 674         }
 675         return count;
 676 }
 677
 678 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 679                              struct bin_attribute *bin_attr,
 680                              char *buf, loff_t pos, size_t count)
 681 {
 682         struct efi_variable *del_var = (struct efi_variable *)buf;
 683         struct efivars *efivars = bin_attr->private;
 684         struct efivar_entry *search_efivar, *n;
 685         unsigned long strsize1, strsize2;
 686         efi_status_t status = EFI_NOT_FOUND;
 687         int found = 0;
 688
 689         if (!capable(CAP_SYS_ADMIN))
 690                 return -EACCES;
 691
 692         spin_lock(&efivars->lock);
 693
 694         /*
 695          * Does this variable already exist?
 696          */
 697         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
 698                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
 699                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
 700                 if (strsize1 == strsize2 &&
 701                         !memcmp(&(search_efivar->var.VariableName),
 702                                 del_var->VariableName, strsize1) &&
 703                         !efi_guidcmp(search_efivar->var.VendorGuid,
 704                                 del_var->VendorGuid)) {
 705                         found = 1;
 706                         break;
 707                 }
 708         }
 709         if (!found) {
 710                 spin_unlock(&efivars->lock);
 711                 return -EINVAL;
 712         }
 713         /* force the Attributes/DataSize to 0 to ensure deletion */
 714         del_var->Attributes = 0;
 715         del_var->DataSize = 0;
 716
 717         status = efivars->ops->set_variable(del_var->VariableName,
 718                                             &del_var->VendorGuid,
 719                                             del_var->Attributes,
 720                                             del_var->DataSize,
 721                                             del_var->Data);
 722
 723         if (status != EFI_SUCCESS) {
 724                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
 725                         status);
 726                 spin_unlock(&efivars->lock);
 727                 return -EIO;
 728         }
 729         list_del(&search_efivar->list);
 730         /* We need to release this lock before unregistering. */
 731         spin_unlock(&efivars->lock);
 732         efivar_unregister(search_efivar);
 733
 734         /* It's dead Jim.... */
 735         return count;
 736 }
 737
 738 /*
 739  * Let's not leave out systab information that snuck into
 740  * the efivars driver
 741  */
 742 static ssize_t systab_show(struct kobject *kobj,
 743                            struct kobj_attribute *attr, char *buf)
 744 {
 745         char *str = buf;
 746
 747         if (!kobj || !buf)
 748                 return -EINVAL;
 749
 750         if (efi.mps != EFI_INVALID_TABLE_ADDR)
 751                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
 752         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
 753                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 754         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 755                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
 756         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
 757                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 758         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 759                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 760         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
 761                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
 762         if (efi.uga != EFI_INVALID_TABLE_ADDR)
 763                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
 764
 765         return str - buf;
 766 }
 767
 768 static struct kobj_attribute efi_attr_systab =
 769                         __ATTR(systab, 0400, systab_show, NULL);
 770
 771 static struct attribute *efi_subsys_attrs[] = {
 772         &efi_attr_systab.attr,
 773         NULL,   /* maybe more in the future? */
 774 };
 775
 776 static struct attribute_group efi_subsys_attr_group = {
 777         .attrs = efi_subsys_attrs,
 778 };
 779
 780 static struct kobject *efi_kobj;
 781
 782 /*
 783  * efivar_create_sysfs_entry()
 784  * Requires:
 785  *    variable_name_size = number of bytes required to hold
 786  *                         variable_name (not counting the NULL
 787  *                         character at the end.
 788  *    efivars->lock is not held on entry or exit.
 789  * Returns 1 on failure, 0 on success
 790  */
 791 static int
 792 efivar_create_sysfs_entry(struct efivars *efivars,
 793                           unsigned long variable_name_size,
 794                           efi_char16_t *variable_name,
 795                           efi_guid_t *vendor_guid)
 796 {
 797         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
 798         char *short_name;
 799         struct efivar_entry *new_efivar;
 800
 801         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
 802         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 803
 804         if (!short_name || !new_efivar)  {
 805                 kfree(short_name);
 806                 kfree(new_efivar);
 807                 return 1;
 808         }
 809
 810         new_efivar->efivars = efivars;
 811         memcpy(new_efivar->var.VariableName, variable_name,
 812                 variable_name_size);
 813         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
 814
 815         /* Convert Unicode to normal chars (assume top bits are 0),
 816            ala UTF-8 */
 817         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
 818                 short_name[i] = variable_name[i] & 0xFF;
 819         }
 820         /* This is ugly, but necessary to separate one vendor's
 821            private variables from another's.         */
 822
 823         *(short_name + strlen(short_name)) = '-';
 824         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
 825
 826         new_efivar->kobj.kset = efivars->kset;
 827         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
 828                                  "%s", short_name);
 829         if (i) {
 830                 kfree(short_name);
 831                 kfree(new_efivar);
 832                 return 1;
 833         }
 834
 835         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
 836         kfree(short_name);
 837         short_name = NULL;
 838
 839         spin_lock(&efivars->lock);
 840         list_add(&new_efivar->list, &efivars->list);
 841         spin_unlock(&efivars->lock);
 842
 843         return 0;
 844 }
 845
 846 static int
 847 create_efivars_bin_attributes(struct efivars *efivars)
 848 {
 849         struct bin_attribute *attr;
 850         int error;
 851
 852         /* new_var */
 853         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 854         if (!attr)
 855                 return -ENOMEM;
 856
 857         attr->attr.name = "new_var";
 858         attr->attr.mode = 0200;
 859         attr->write = efivar_create;
 860         attr->private = efivars;
 861         efivars->new_var = attr;
 862
 863         /* del_var */
 864         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 865         if (!attr) {
 866                 error = -ENOMEM;
 867                 goto out_free;
 868         }
 869         attr->attr.name = "del_var";
 870         attr->attr.mode = 0200;
 871         attr->write = efivar_delete;
 872         attr->private = efivars;
 873         efivars->del_var = attr;
 874
 875         sysfs_bin_attr_init(efivars->new_var);
 876         sysfs_bin_attr_init(efivars->del_var);
 877
 878         /* Register */
 879         error = sysfs_create_bin_file(&efivars->kset->kobj,
 880                                       efivars->new_var);
 881         if (error) {
 882                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
 883                         " due to error %d\n", error);
 884                 goto out_free;
 885         }
 886         error = sysfs_create_bin_file(&efivars->kset->kobj,
 887                                       efivars->del_var);
 888         if (error) {
 889                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
 890                         " due to error %d\n", error);
 891                 sysfs_remove_bin_file(&efivars->kset->kobj,
 892                                       efivars->new_var);
 893                 goto out_free;
 894         }
 895
 896         return 0;
 897 out_free:
 898         kfree(efivars->del_var);
 899         efivars->del_var = NULL;
 900         kfree(efivars->new_var);
 901         efivars->new_var = NULL;
 902         return error;
 903 }
 904
 905 void unregister_efivars(struct efivars *efivars)
 906 {
 907         struct efivar_entry *entry, *n;
 908
 909         list_for_each_entry_safe(entry, n, &efivars->list, list) {
 910                 spin_lock(&efivars->lock);
 911                 list_del(&entry->list);
 912                 spin_unlock(&efivars->lock);
 913                 efivar_unregister(entry);
 914         }
 915         if (efivars->new_var)
 916                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
 917         if (efivars->del_var)
 918                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
 919         kfree(efivars->new_var);
 920         kfree(efivars->del_var);
 921         kset_unregister(efivars->kset);
 922 }
 923 EXPORT_SYMBOL_GPL(unregister_efivars);
 924
 925 int register_efivars(struct efivars *efivars,
 926                      const struct efivar_operations *ops,
 927                      struct kobject *parent_kobj)
 928 {
 929         efi_status_t status = EFI_NOT_FOUND;
 930         efi_guid_t vendor_guid;
 931         efi_char16_t *variable_name;
 932         unsigned long variable_name_size = 1024;
 933         int error = 0;
 934
 935         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
 936         if (!variable_name) {
 937                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
 938                 return -ENOMEM;
 939         }
 940
 941         spin_lock_init(&efivars->lock);
 942         INIT_LIST_HEAD(&efivars->list);
 943         efivars->ops = ops;
 944
 945         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
 946         if (!efivars->kset) {
 947                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
 948                 error = -ENOMEM;
 949                 goto out;
 950         }
 951
 952         /*
 953          * Per EFI spec, the maximum storage allocated for both
 954          * the variable name and variable data is 1024 bytes.
 955          */
 956
 957         do {
 958                 variable_name_size = 1024;
 959
 960                 status = ops->get_next_variable(&variable_name_size,
 961                                                 variable_name,
 962                                                 &vendor_guid);
 963                 switch (status) {
 964                 case EFI_SUCCESS:
 965                         efivar_create_sysfs_entry(efivars,
 966                                                   variable_name_size,
 967                                                   variable_name,
 968                                                   &vendor_guid);
 969                         break;
 970                 case EFI_NOT_FOUND:
 971                         break;
 972                 default:
 973                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
 974                                 status);
 975                         status = EFI_NOT_FOUND;
 976                         break;
 977                 }
 978         } while (status != EFI_NOT_FOUND);
 979
 980         error = create_efivars_bin_attributes(efivars);
 981         if (error)
 982                 unregister_efivars(efivars);
 983
 984         efivars->efi_pstore_info = efi_pstore_info;
 985
 986         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
 987         if (efivars->efi_pstore_info.buf) {
 988                 efivars->efi_pstore_info.bufsize = 1024;
 989                 efivars->efi_pstore_info.data = efivars;
 990                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
 991                 pstore_register(&efivars->efi_pstore_info);
 992         }
 993
 994 out:
 995         kfree(variable_name);
 996
 997         return error;
 998 }
 999 EXPORT_SYMBOL_GPL(register_efivars);
1000
1001 static struct efivars __efivars;
1002 static struct efivar_operations ops;
1003
1004 /*
1005  * For now we register the efi subsystem with the firmware subsystem
1006  * and the vars subsystem with the efi subsystem.  In the future, it
1007  * might make sense to split off the efi subsystem into its own
1008  * driver, but for now only efivars will register with it, so just
1009  * include it here.
1010  */
1011
1012 static int __init
1013 efivars_init(void)
1014 {
1015         int error = 0;
1016
1017         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1018                EFIVARS_DATE);
1019
1020         if (!efi_enabled)
1021                 return 0;
1022
1023         /* For now we'll register the efi directory at /sys/firmware/efi */
1024         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1025         if (!efi_kobj) {
1026                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1027                 return -ENOMEM;
1028         }
1029
1030         ops.get_variable = efi.get_variable;
1031         ops.set_variable = efi.set_variable;
1032         ops.get_next_variable = efi.get_next_variable;
1033         error = register_efivars(&__efivars, &ops, efi_kobj);
1034         if (error)
1035                 goto err_put;
1036
1037         /* Don't forget the systab entry */
1038         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1039         if (error) {
1040                 printk(KERN_ERR
1041                        "efivars: Sysfs attribute export failed with error %d.\n",
1042                        error);
1043                 goto err_unregister;
1044         }
1045
1046         return 0;
1047
1048 err_unregister:
1049         unregister_efivars(&__efivars);
1050 err_put:
1051         kobject_put(efi_kobj);
1052         return error;
1053 }
1054
1055 static void __exit
1056 efivars_exit(void)
1057 {
1058         if (efi_enabled) {
1059                 unregister_efivars(&__efivars);
1060                 kobject_put(efi_kobj);
1061         }
1062 }
1063
1064 module_init(efivars_init);
1065 module_exit(efivars_exit);
1066