2 * EFI Variables - efivars.c
4 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
7 * This code takes all variables accessible from EFI runtime and
8 * exports them via sysfs
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.
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.
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
26 * 17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27 * remove check for efi_enabled in exit
30 * 26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
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
38 * 10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39 * fix locking per Peter Chubb's findings
41 * 25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42 * move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
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
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
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.
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
64 * 26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65 * v0.01 release to linux-ia64@linuxia64.org
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.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>
83 #include <asm/uaccess.h>
85 #define EFIVARS_VERSION "0.08"
86 #define EFIVARS_DATE "2004-May-17"
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);
93 #define DUMP_NAME_LEN 52
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.
102 struct efi_variable {
103 efi_char16_t VariableName[1024/sizeof(efi_char16_t)];
104 efi_guid_t VendorGuid;
105 unsigned long DataSize;
109 } __attribute__((packed));
112 struct efivar_entry {
113 struct efivars *efivars;
114 struct efi_variable var;
115 struct list_head list;
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);
125 #define PSTORE_EFI_ATTRIBUTES \
126 (EFI_VARIABLE_NON_VOLATILE | \
127 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
128 EFI_VARIABLE_RUNTIME_ACCESS)
130 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
131 struct efivar_attribute efivar_attr_##_name = { \
132 .attr = {.name = __stringify(_name), .mode = _mode}, \
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)
141 * Prototype for sysfs creation function
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);
149 /* Return the number of unicode characters in data */
151 utf16_strnlen(efi_char16_t *s, size_t maxlength)
153 unsigned long length = 0;
155 while (*s++ != 0 && length < maxlength)
160 static inline unsigned long
161 utf16_strlen(efi_char16_t *s)
163 return utf16_strnlen(s, ~0UL);
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
170 static inline unsigned long
171 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
173 return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
177 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
186 if (*a == 0) /* implies *b == 0 */
195 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
198 struct efi_generic_dev_path *node;
201 node = (struct efi_generic_dev_path *)buffer;
203 if (len < sizeof(*node))
206 while (offset <= len - sizeof(*node) &&
207 node->length >= sizeof(*node) &&
208 node->length <= len - offset) {
209 offset += node->length;
211 if ((node->type == EFI_DEV_END_PATH ||
212 node->type == EFI_DEV_END_PATH2) &&
213 node->sub_type == EFI_DEV_END_ENTIRE)
216 node = (struct efi_generic_dev_path *)(buffer + offset);
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.
228 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
231 /* An array of 16-bit integers */
239 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
243 int i, desclength = 0, namelen;
245 namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
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)
254 /* Reject it if there's 4 digits of hex and then further content */
255 if (namelen > match + 4)
258 /* A valid entry must be at least 8 bytes */
262 filepathlength = buffer[4] | buffer[5] << 8;
265 * There's no stored length for the description, so it has to be
268 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
270 /* Each boot entry must have a descriptor */
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
279 if ((desclength + filepathlength + 6) > len)
283 * And, finally, check the filepath
285 return validate_device_path(var, match, buffer + desclength + 6,
290 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
293 /* A single 16-bit integer */
301 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
306 for (i = 0; i < len; i++) {
317 struct variable_validate {
319 bool (*validate)(struct efi_variable *var, int match, u8 *data,
323 static 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 },
342 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
345 u16 *unicode_name = var->VariableName;
347 for (i = 0; variable_validate[i].validate != NULL; i++) {
348 const char *name = variable_validate[i].name;
351 for (match = 0; ; match++) {
352 char c = name[match];
353 u16 u = unicode_name[match];
355 /* All special variables are plain ascii */
359 /* Wildcard in the matching name means we've matched */
361 return variable_validate[i].validate(var,
364 /* Case sensitive match */
368 /* Reached the end of the string while matching */
370 return variable_validate[i].validate(var,
379 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
383 var->DataSize = 1024;
384 status = efivars->ops->get_variable(var->VariableName,
393 get_var_data(struct efivars *efivars, struct efi_variable *var)
397 spin_lock(&efivars->lock);
398 status = get_var_data_locked(efivars, var);
399 spin_unlock(&efivars->lock);
401 if (status != EFI_SUCCESS) {
402 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
409 efivar_guid_read(struct efivar_entry *entry, char *buf)
411 struct efi_variable *var = &entry->var;
417 efi_guid_unparse(&var->VendorGuid, str);
419 str += sprintf(str, "\n");
425 efivar_attr_read(struct efivar_entry *entry, char *buf)
427 struct efi_variable *var = &entry->var;
434 status = get_var_data(entry->efivars, var);
435 if (status != EFI_SUCCESS)
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");
448 efivar_size_read(struct efivar_entry *entry, char *buf)
450 struct efi_variable *var = &entry->var;
457 status = get_var_data(entry->efivars, var);
458 if (status != EFI_SUCCESS)
461 str += sprintf(str, "0x%lx\n", var->DataSize);
466 efivar_data_read(struct efivar_entry *entry, char *buf)
468 struct efi_variable *var = &entry->var;
474 status = get_var_data(entry->efivars, var);
475 if (status != EFI_SUCCESS)
478 memcpy(buf, var->Data, var->DataSize);
479 return var->DataSize;
482 * We allow each variable to be edited via rewriting the
483 * entire efi variable structure.
486 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
488 struct efi_variable *new_var, *var = &entry->var;
489 struct efivars *efivars = entry->efivars;
490 efi_status_t status = EFI_NOT_FOUND;
492 if (count != sizeof(struct efi_variable))
495 new_var = (struct efi_variable *)buf;
497 * If only updating the variable data, then the name
498 * and guid should remain the same
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");
506 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
507 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
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");
517 spin_lock(&efivars->lock);
518 status = efivars->ops->set_variable(new_var->VariableName,
519 &new_var->VendorGuid,
524 spin_unlock(&efivars->lock);
526 if (status != EFI_SUCCESS) {
527 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
532 memcpy(&entry->var, new_var, count);
537 efivar_show_raw(struct efivar_entry *entry, char *buf)
539 struct efi_variable *var = &entry->var;
545 status = get_var_data(entry->efivars, var);
546 if (status != EFI_SUCCESS)
549 memcpy(buf, var, sizeof(*var));
554 * Generic read/write functions that call the specific functions of
557 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
560 struct efivar_entry *var = to_efivar_entry(kobj);
561 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
564 if (!capable(CAP_SYS_ADMIN))
567 if (efivar_attr->show) {
568 ret = efivar_attr->show(var, buf);
573 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
574 const char *buf, size_t count)
576 struct efivar_entry *var = to_efivar_entry(kobj);
577 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
580 if (!capable(CAP_SYS_ADMIN))
583 if (efivar_attr->store)
584 ret = efivar_attr->store(var, buf, count);
589 static const struct sysfs_ops efivar_attr_ops = {
590 .show = efivar_attr_show,
591 .store = efivar_attr_store,
594 static void efivar_release(struct kobject *kobj)
596 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
600 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
601 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
602 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
603 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
604 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
606 static 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,
615 static struct kobj_type efivar_ktype = {
616 .release = efivar_release,
617 .sysfs_ops = &efivar_attr_ops,
618 .default_attrs = def_attrs,
621 static struct pstore_info efi_pstore_info;
624 efivar_unregister(struct efivar_entry *var)
626 kobject_put(&var->kobj);
631 static int efi_pstore_open(struct pstore_info *psi)
633 struct efivars *efivars = psi->data;
635 spin_lock(&efivars->lock);
636 efivars->walk_entry = list_first_entry(&efivars->list,
637 struct efivar_entry, list);
641 static int efi_pstore_close(struct pstore_info *psi)
643 struct efivars *efivars = psi->data;
645 spin_unlock(&efivars->lock);
649 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
650 struct timespec *timespec,
651 char **buf, struct pstore_info *psi)
653 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
654 struct efivars *efivars = psi->data;
655 char name[DUMP_NAME_LEN];
657 unsigned int part, size;
660 while (&efivars->walk_entry->list != &efivars->list) {
661 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
663 for (i = 0; i < DUMP_NAME_LEN; i++) {
664 name[i] = efivars->walk_entry->var.VariableName[i];
666 if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
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);
675 memcpy(*buf, efivars->walk_entry->var.Data,
677 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
678 struct efivar_entry, list);
682 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
683 struct efivar_entry, list);
688 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
689 unsigned int part, size_t size, struct pstore_info *psi)
691 char name[DUMP_NAME_LEN];
692 char stub_name[DUMP_NAME_LEN];
693 efi_char16_t efi_name[DUMP_NAME_LEN];
694 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
695 struct efivars *efivars = psi->data;
696 struct efivar_entry *entry, *found = NULL;
699 sprintf(stub_name, "dump-type%u-%u-", type, part);
700 sprintf(name, "%s%lu", stub_name, get_seconds());
702 spin_lock(&efivars->lock);
704 for (i = 0; i < DUMP_NAME_LEN; i++)
705 efi_name[i] = stub_name[i];
708 * Clean up any entries with the same name
711 list_for_each_entry(entry, &efivars->list, list) {
712 get_var_data_locked(efivars, &entry->var);
714 if (efi_guidcmp(entry->var.VendorGuid, vendor))
716 if (utf16_strncmp(entry->var.VariableName, efi_name,
717 utf16_strlen(efi_name)))
719 /* Needs to be a prefix */
720 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
725 efivars->ops->set_variable(entry->var.VariableName,
726 &entry->var.VendorGuid,
727 PSTORE_EFI_ATTRIBUTES,
732 list_del(&found->list);
734 for (i = 0; i < DUMP_NAME_LEN; i++)
735 efi_name[i] = name[i];
737 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
740 spin_unlock(&efivars->lock);
743 efivar_unregister(found);
746 ret = efivar_create_sysfs_entry(efivars,
747 utf16_strsize(efi_name,
755 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
756 struct pstore_info *psi)
758 efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
763 static int efi_pstore_open(struct pstore_info *psi)
768 static int efi_pstore_close(struct pstore_info *psi)
773 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
774 struct timespec *timespec,
775 char **buf, struct pstore_info *psi)
780 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
781 unsigned int part, size_t size, struct pstore_info *psi)
786 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
787 struct pstore_info *psi)
793 static struct pstore_info efi_pstore_info = {
794 .owner = THIS_MODULE,
796 .open = efi_pstore_open,
797 .close = efi_pstore_close,
798 .read = efi_pstore_read,
799 .write = efi_pstore_write,
800 .erase = efi_pstore_erase,
803 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
804 struct bin_attribute *bin_attr,
805 char *buf, loff_t pos, size_t count)
807 struct efi_variable *new_var = (struct efi_variable *)buf;
808 struct efivars *efivars = bin_attr->private;
809 struct efivar_entry *search_efivar, *n;
810 unsigned long strsize1, strsize2;
811 efi_status_t status = EFI_NOT_FOUND;
814 if (!capable(CAP_SYS_ADMIN))
817 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
818 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
819 printk(KERN_ERR "efivars: Malformed variable content\n");
823 spin_lock(&efivars->lock);
826 * Does this variable already exist?
828 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
829 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
830 strsize2 = utf16_strsize(new_var->VariableName, 1024);
831 if (strsize1 == strsize2 &&
832 !memcmp(&(search_efivar->var.VariableName),
833 new_var->VariableName, strsize1) &&
834 !efi_guidcmp(search_efivar->var.VendorGuid,
835 new_var->VendorGuid)) {
841 spin_unlock(&efivars->lock);
845 /* now *really* create the variable via EFI */
846 status = efivars->ops->set_variable(new_var->VariableName,
847 &new_var->VendorGuid,
852 if (status != EFI_SUCCESS) {
853 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
855 spin_unlock(&efivars->lock);
858 spin_unlock(&efivars->lock);
860 /* Create the entry in sysfs. Locking is not required here */
861 status = efivar_create_sysfs_entry(efivars,
862 utf16_strsize(new_var->VariableName,
864 new_var->VariableName,
865 &new_var->VendorGuid);
867 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
872 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
873 struct bin_attribute *bin_attr,
874 char *buf, loff_t pos, size_t count)
876 struct efi_variable *del_var = (struct efi_variable *)buf;
877 struct efivars *efivars = bin_attr->private;
878 struct efivar_entry *search_efivar, *n;
879 unsigned long strsize1, strsize2;
880 efi_status_t status = EFI_NOT_FOUND;
883 if (!capable(CAP_SYS_ADMIN))
886 spin_lock(&efivars->lock);
889 * Does this variable already exist?
891 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
892 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
893 strsize2 = utf16_strsize(del_var->VariableName, 1024);
894 if (strsize1 == strsize2 &&
895 !memcmp(&(search_efivar->var.VariableName),
896 del_var->VariableName, strsize1) &&
897 !efi_guidcmp(search_efivar->var.VendorGuid,
898 del_var->VendorGuid)) {
904 spin_unlock(&efivars->lock);
907 /* force the Attributes/DataSize to 0 to ensure deletion */
908 del_var->Attributes = 0;
909 del_var->DataSize = 0;
911 status = efivars->ops->set_variable(del_var->VariableName,
912 &del_var->VendorGuid,
917 if (status != EFI_SUCCESS) {
918 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
920 spin_unlock(&efivars->lock);
923 list_del(&search_efivar->list);
924 /* We need to release this lock before unregistering. */
925 spin_unlock(&efivars->lock);
926 efivar_unregister(search_efivar);
928 /* It's dead Jim.... */
933 * Let's not leave out systab information that snuck into
936 static ssize_t systab_show(struct kobject *kobj,
937 struct kobj_attribute *attr, char *buf)
944 if (efi.mps != EFI_INVALID_TABLE_ADDR)
945 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
946 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
947 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
948 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
949 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
950 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
951 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
952 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
953 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
954 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
955 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
956 if (efi.uga != EFI_INVALID_TABLE_ADDR)
957 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
962 static struct kobj_attribute efi_attr_systab =
963 __ATTR(systab, 0400, systab_show, NULL);
965 static struct attribute *efi_subsys_attrs[] = {
966 &efi_attr_systab.attr,
967 NULL, /* maybe more in the future? */
970 static struct attribute_group efi_subsys_attr_group = {
971 .attrs = efi_subsys_attrs,
974 static struct kobject *efi_kobj;
977 * efivar_create_sysfs_entry()
979 * variable_name_size = number of bytes required to hold
980 * variable_name (not counting the NULL
981 * character at the end.
982 * efivars->lock is not held on entry or exit.
983 * Returns 1 on failure, 0 on success
986 efivar_create_sysfs_entry(struct efivars *efivars,
987 unsigned long variable_name_size,
988 efi_char16_t *variable_name,
989 efi_guid_t *vendor_guid)
991 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
993 struct efivar_entry *new_efivar;
995 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
996 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
998 if (!short_name || !new_efivar) {
1004 new_efivar->efivars = efivars;
1005 memcpy(new_efivar->var.VariableName, variable_name,
1006 variable_name_size);
1007 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1009 /* Convert Unicode to normal chars (assume top bits are 0),
1011 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1012 short_name[i] = variable_name[i] & 0xFF;
1014 /* This is ugly, but necessary to separate one vendor's
1015 private variables from another's. */
1017 *(short_name + strlen(short_name)) = '-';
1018 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1020 new_efivar->kobj.kset = efivars->kset;
1021 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1029 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1033 spin_lock(&efivars->lock);
1034 list_add(&new_efivar->list, &efivars->list);
1035 spin_unlock(&efivars->lock);
1041 create_efivars_bin_attributes(struct efivars *efivars)
1043 struct bin_attribute *attr;
1047 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1051 attr->attr.name = "new_var";
1052 attr->attr.mode = 0200;
1053 attr->write = efivar_create;
1054 attr->private = efivars;
1055 efivars->new_var = attr;
1058 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1063 attr->attr.name = "del_var";
1064 attr->attr.mode = 0200;
1065 attr->write = efivar_delete;
1066 attr->private = efivars;
1067 efivars->del_var = attr;
1069 sysfs_bin_attr_init(efivars->new_var);
1070 sysfs_bin_attr_init(efivars->del_var);
1073 error = sysfs_create_bin_file(&efivars->kset->kobj,
1076 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1077 " due to error %d\n", error);
1080 error = sysfs_create_bin_file(&efivars->kset->kobj,
1083 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1084 " due to error %d\n", error);
1085 sysfs_remove_bin_file(&efivars->kset->kobj,
1092 kfree(efivars->del_var);
1093 efivars->del_var = NULL;
1094 kfree(efivars->new_var);
1095 efivars->new_var = NULL;
1099 void unregister_efivars(struct efivars *efivars)
1101 struct efivar_entry *entry, *n;
1103 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1104 spin_lock(&efivars->lock);
1105 list_del(&entry->list);
1106 spin_unlock(&efivars->lock);
1107 efivar_unregister(entry);
1109 if (efivars->new_var)
1110 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1111 if (efivars->del_var)
1112 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1113 kfree(efivars->new_var);
1114 kfree(efivars->del_var);
1115 kset_unregister(efivars->kset);
1117 EXPORT_SYMBOL_GPL(unregister_efivars);
1119 int register_efivars(struct efivars *efivars,
1120 const struct efivar_operations *ops,
1121 struct kobject *parent_kobj)
1123 efi_status_t status = EFI_NOT_FOUND;
1124 efi_guid_t vendor_guid;
1125 efi_char16_t *variable_name;
1126 unsigned long variable_name_size = 1024;
1129 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1130 if (!variable_name) {
1131 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1135 spin_lock_init(&efivars->lock);
1136 INIT_LIST_HEAD(&efivars->list);
1139 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1140 if (!efivars->kset) {
1141 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1147 * Per EFI spec, the maximum storage allocated for both
1148 * the variable name and variable data is 1024 bytes.
1152 variable_name_size = 1024;
1154 status = ops->get_next_variable(&variable_name_size,
1159 efivar_create_sysfs_entry(efivars,
1167 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1169 status = EFI_NOT_FOUND;
1172 } while (status != EFI_NOT_FOUND);
1174 error = create_efivars_bin_attributes(efivars);
1176 unregister_efivars(efivars);
1178 efivars->efi_pstore_info = efi_pstore_info;
1180 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1181 if (efivars->efi_pstore_info.buf) {
1182 efivars->efi_pstore_info.bufsize = 1024;
1183 efivars->efi_pstore_info.data = efivars;
1184 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1185 pstore_register(&efivars->efi_pstore_info);
1189 kfree(variable_name);
1193 EXPORT_SYMBOL_GPL(register_efivars);
1195 static struct efivars __efivars;
1196 static struct efivar_operations ops;
1199 * For now we register the efi subsystem with the firmware subsystem
1200 * and the vars subsystem with the efi subsystem. In the future, it
1201 * might make sense to split off the efi subsystem into its own
1202 * driver, but for now only efivars will register with it, so just
1211 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1217 /* For now we'll register the efi directory at /sys/firmware/efi */
1218 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1220 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1224 ops.get_variable = efi.get_variable;
1225 ops.set_variable = efi.set_variable;
1226 ops.get_next_variable = efi.get_next_variable;
1227 error = register_efivars(&__efivars, &ops, efi_kobj);
1231 /* Don't forget the systab entry */
1232 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1235 "efivars: Sysfs attribute export failed with error %d.\n",
1237 goto err_unregister;
1243 unregister_efivars(&__efivars);
1245 kobject_put(efi_kobj);
1253 unregister_efivars(&__efivars);
1254 kobject_put(efi_kobj);
1258 module_init(efivars_init);
1259 module_exit(efivars_exit);