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, int len)
197 struct efi_generic_dev_path *node;
200 node = (struct efi_generic_dev_path *)buffer;
202 while (offset < len) {
203 offset += node->length;
208 if ((node->type == EFI_DEV_END_PATH ||
209 node->type == EFI_DEV_END_PATH2) &&
210 node->sub_type == EFI_DEV_END_ENTIRE)
213 node = (struct efi_generic_dev_path *)(buffer + offset);
217 * If we're here then either node->length pointed past the end
218 * of the buffer or we reached the end of the buffer without
219 * finding a device path end node.
225 validate_boot_order(struct efi_variable *var, int match, u8 *buffer, int len)
227 /* An array of 16-bit integers */
235 validate_load_option(struct efi_variable *var, int match, u8 *buffer, int len)
238 int i, desclength = 0;
240 /* Either "Boot" or "Driver" followed by four digits of hex */
241 for (i = match; i < match+4; i++) {
242 if (hex_to_bin(var->VariableName[i] & 0xff) < 0)
246 /* A valid entry must be at least 6 bytes */
250 filepathlength = buffer[4] | buffer[5] << 8;
253 * There's no stored length for the description, so it has to be
256 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len) + 2;
258 /* Each boot entry must have a descriptor */
263 * If the sum of the length of the description, the claimed filepath
264 * length and the original header are greater than the length of the
265 * variable, it's malformed
267 if ((desclength + filepathlength + 6) > len)
271 * And, finally, check the filepath
273 return validate_device_path(var, match, buffer + desclength + 6,
278 validate_uint16(struct efi_variable *var, int match, u8 *buffer, int len)
280 /* A single 16-bit integer */
288 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer, int len)
292 for (i = 0; i < len; i++) {
303 struct variable_validate {
305 bool (*validate)(struct efi_variable *var, int match, u8 *data,
309 static const struct variable_validate variable_validate[] = {
310 { "BootNext", validate_uint16 },
311 { "BootOrder", validate_boot_order },
312 { "DriverOrder", validate_boot_order },
313 { "Boot*", validate_load_option },
314 { "Driver*", validate_load_option },
315 { "ConIn", validate_device_path },
316 { "ConInDev", validate_device_path },
317 { "ConOut", validate_device_path },
318 { "ConOutDev", validate_device_path },
319 { "ErrOut", validate_device_path },
320 { "ErrOutDev", validate_device_path },
321 { "Timeout", validate_uint16 },
322 { "Lang", validate_ascii_string },
323 { "PlatformLang", validate_ascii_string },
328 validate_var(struct efi_variable *var, u8 *data, int len)
331 u16 *unicode_name = var->VariableName;
333 for (i = 0; variable_validate[i].validate != NULL; i++) {
334 const char *name = variable_validate[i].name;
337 for (match = 0; ; match++) {
338 char c = name[match];
339 u16 u = unicode_name[match];
341 /* All special variables are plain ascii */
345 /* Wildcard in the matching name means we've matched */
347 return variable_validate[i].validate(var,
350 /* Case sensitive match */
354 /* Reached the end of the string while matching */
356 return variable_validate[i].validate(var,
365 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
369 var->DataSize = 1024;
370 status = efivars->ops->get_variable(var->VariableName,
379 get_var_data(struct efivars *efivars, struct efi_variable *var)
383 spin_lock(&efivars->lock);
384 status = get_var_data_locked(efivars, var);
385 spin_unlock(&efivars->lock);
387 if (status != EFI_SUCCESS) {
388 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
395 efivar_guid_read(struct efivar_entry *entry, char *buf)
397 struct efi_variable *var = &entry->var;
403 efi_guid_unparse(&var->VendorGuid, str);
405 str += sprintf(str, "\n");
411 efivar_attr_read(struct efivar_entry *entry, char *buf)
413 struct efi_variable *var = &entry->var;
420 status = get_var_data(entry->efivars, var);
421 if (status != EFI_SUCCESS)
424 if (var->Attributes & 0x1)
425 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
426 if (var->Attributes & 0x2)
427 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
428 if (var->Attributes & 0x4)
429 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
434 efivar_size_read(struct efivar_entry *entry, char *buf)
436 struct efi_variable *var = &entry->var;
443 status = get_var_data(entry->efivars, var);
444 if (status != EFI_SUCCESS)
447 str += sprintf(str, "0x%lx\n", var->DataSize);
452 efivar_data_read(struct efivar_entry *entry, char *buf)
454 struct efi_variable *var = &entry->var;
460 status = get_var_data(entry->efivars, var);
461 if (status != EFI_SUCCESS)
464 memcpy(buf, var->Data, var->DataSize);
465 return var->DataSize;
468 * We allow each variable to be edited via rewriting the
469 * entire efi variable structure.
472 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
474 struct efi_variable *new_var, *var = &entry->var;
475 struct efivars *efivars = entry->efivars;
476 efi_status_t status = EFI_NOT_FOUND;
478 if (count != sizeof(struct efi_variable))
481 new_var = (struct efi_variable *)buf;
483 * If only updating the variable data, then the name
484 * and guid should remain the same
486 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
487 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
488 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
492 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
493 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
497 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
498 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
499 printk(KERN_ERR "efivars: Malformed variable content\n");
503 spin_lock(&efivars->lock);
504 status = efivars->ops->set_variable(new_var->VariableName,
505 &new_var->VendorGuid,
510 spin_unlock(&efivars->lock);
512 if (status != EFI_SUCCESS) {
513 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
518 memcpy(&entry->var, new_var, count);
523 efivar_show_raw(struct efivar_entry *entry, char *buf)
525 struct efi_variable *var = &entry->var;
531 status = get_var_data(entry->efivars, var);
532 if (status != EFI_SUCCESS)
535 memcpy(buf, var, sizeof(*var));
540 * Generic read/write functions that call the specific functions of
543 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
546 struct efivar_entry *var = to_efivar_entry(kobj);
547 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
550 if (!capable(CAP_SYS_ADMIN))
553 if (efivar_attr->show) {
554 ret = efivar_attr->show(var, buf);
559 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
560 const char *buf, size_t count)
562 struct efivar_entry *var = to_efivar_entry(kobj);
563 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
566 if (!capable(CAP_SYS_ADMIN))
569 if (efivar_attr->store)
570 ret = efivar_attr->store(var, buf, count);
575 static const struct sysfs_ops efivar_attr_ops = {
576 .show = efivar_attr_show,
577 .store = efivar_attr_store,
580 static void efivar_release(struct kobject *kobj)
582 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
586 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
587 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
588 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
589 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
590 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
592 static struct attribute *def_attrs[] = {
593 &efivar_attr_guid.attr,
594 &efivar_attr_size.attr,
595 &efivar_attr_attributes.attr,
596 &efivar_attr_data.attr,
597 &efivar_attr_raw_var.attr,
601 static struct kobj_type efivar_ktype = {
602 .release = efivar_release,
603 .sysfs_ops = &efivar_attr_ops,
604 .default_attrs = def_attrs,
607 static struct pstore_info efi_pstore_info;
610 efivar_unregister(struct efivar_entry *var)
612 kobject_put(&var->kobj);
617 static int efi_pstore_open(struct pstore_info *psi)
619 struct efivars *efivars = psi->data;
621 spin_lock(&efivars->lock);
622 efivars->walk_entry = list_first_entry(&efivars->list,
623 struct efivar_entry, list);
627 static int efi_pstore_close(struct pstore_info *psi)
629 struct efivars *efivars = psi->data;
631 spin_unlock(&efivars->lock);
635 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
636 struct timespec *timespec,
637 char **buf, struct pstore_info *psi)
639 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
640 struct efivars *efivars = psi->data;
641 char name[DUMP_NAME_LEN];
643 unsigned int part, size;
646 while (&efivars->walk_entry->list != &efivars->list) {
647 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
649 for (i = 0; i < DUMP_NAME_LEN; i++) {
650 name[i] = efivars->walk_entry->var.VariableName[i];
652 if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
654 timespec->tv_sec = time;
655 timespec->tv_nsec = 0;
656 get_var_data_locked(efivars, &efivars->walk_entry->var);
657 size = efivars->walk_entry->var.DataSize;
658 *buf = kmalloc(size, GFP_KERNEL);
661 memcpy(*buf, efivars->walk_entry->var.Data,
663 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
664 struct efivar_entry, list);
668 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
669 struct efivar_entry, list);
674 static int efi_pstore_write(enum pstore_type_id type,
675 enum kmsg_dump_reason reason, u64 *id,
676 unsigned int part, size_t size, struct pstore_info *psi)
678 char name[DUMP_NAME_LEN];
679 char stub_name[DUMP_NAME_LEN];
680 efi_char16_t efi_name[DUMP_NAME_LEN];
681 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
682 struct efivars *efivars = psi->data;
683 struct efivar_entry *entry, *found = NULL;
686 sprintf(stub_name, "dump-type%u-%u-", type, part);
687 sprintf(name, "%s%lu", stub_name, get_seconds());
689 spin_lock(&efivars->lock);
691 for (i = 0; i < DUMP_NAME_LEN; i++)
692 efi_name[i] = stub_name[i];
695 * Clean up any entries with the same name
698 list_for_each_entry(entry, &efivars->list, list) {
699 get_var_data_locked(efivars, &entry->var);
701 if (efi_guidcmp(entry->var.VendorGuid, vendor))
703 if (utf16_strncmp(entry->var.VariableName, efi_name,
704 utf16_strlen(efi_name)))
706 /* Needs to be a prefix */
707 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
712 efivars->ops->set_variable(entry->var.VariableName,
713 &entry->var.VendorGuid,
714 PSTORE_EFI_ATTRIBUTES,
719 list_del(&found->list);
721 for (i = 0; i < DUMP_NAME_LEN; i++)
722 efi_name[i] = name[i];
724 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
727 spin_unlock(&efivars->lock);
730 efivar_unregister(found);
733 ret = efivar_create_sysfs_entry(efivars,
734 utf16_strsize(efi_name,
742 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
743 struct pstore_info *psi)
745 efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
750 static int efi_pstore_open(struct pstore_info *psi)
755 static int efi_pstore_close(struct pstore_info *psi)
760 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
761 struct timespec *timespec,
762 char **buf, struct pstore_info *psi)
767 static int efi_pstore_write(enum pstore_type_id type,
768 enum kmsg_dump_reason reason, u64 *id,
769 unsigned int part, size_t size, struct pstore_info *psi)
774 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
775 struct pstore_info *psi)
781 static struct pstore_info efi_pstore_info = {
782 .owner = THIS_MODULE,
784 .open = efi_pstore_open,
785 .close = efi_pstore_close,
786 .read = efi_pstore_read,
787 .write = efi_pstore_write,
788 .erase = efi_pstore_erase,
791 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
792 struct bin_attribute *bin_attr,
793 char *buf, loff_t pos, size_t count)
795 struct efi_variable *new_var = (struct efi_variable *)buf;
796 struct efivars *efivars = bin_attr->private;
797 struct efivar_entry *search_efivar, *n;
798 unsigned long strsize1, strsize2;
799 efi_status_t status = EFI_NOT_FOUND;
802 if (!capable(CAP_SYS_ADMIN))
805 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
806 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
807 printk(KERN_ERR "efivars: Malformed variable content\n");
811 spin_lock(&efivars->lock);
814 * Does this variable already exist?
816 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
817 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
818 strsize2 = utf16_strsize(new_var->VariableName, 1024);
819 if (strsize1 == strsize2 &&
820 !memcmp(&(search_efivar->var.VariableName),
821 new_var->VariableName, strsize1) &&
822 !efi_guidcmp(search_efivar->var.VendorGuid,
823 new_var->VendorGuid)) {
829 spin_unlock(&efivars->lock);
833 /* now *really* create the variable via EFI */
834 status = efivars->ops->set_variable(new_var->VariableName,
835 &new_var->VendorGuid,
840 if (status != EFI_SUCCESS) {
841 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
843 spin_unlock(&efivars->lock);
846 spin_unlock(&efivars->lock);
848 /* Create the entry in sysfs. Locking is not required here */
849 status = efivar_create_sysfs_entry(efivars,
850 utf16_strsize(new_var->VariableName,
852 new_var->VariableName,
853 &new_var->VendorGuid);
855 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
860 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
861 struct bin_attribute *bin_attr,
862 char *buf, loff_t pos, size_t count)
864 struct efi_variable *del_var = (struct efi_variable *)buf;
865 struct efivars *efivars = bin_attr->private;
866 struct efivar_entry *search_efivar, *n;
867 unsigned long strsize1, strsize2;
868 efi_status_t status = EFI_NOT_FOUND;
871 if (!capable(CAP_SYS_ADMIN))
874 spin_lock(&efivars->lock);
877 * Does this variable already exist?
879 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
880 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
881 strsize2 = utf16_strsize(del_var->VariableName, 1024);
882 if (strsize1 == strsize2 &&
883 !memcmp(&(search_efivar->var.VariableName),
884 del_var->VariableName, strsize1) &&
885 !efi_guidcmp(search_efivar->var.VendorGuid,
886 del_var->VendorGuid)) {
892 spin_unlock(&efivars->lock);
895 /* force the Attributes/DataSize to 0 to ensure deletion */
896 del_var->Attributes = 0;
897 del_var->DataSize = 0;
899 status = efivars->ops->set_variable(del_var->VariableName,
900 &del_var->VendorGuid,
905 if (status != EFI_SUCCESS) {
906 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
908 spin_unlock(&efivars->lock);
911 list_del(&search_efivar->list);
912 /* We need to release this lock before unregistering. */
913 spin_unlock(&efivars->lock);
914 efivar_unregister(search_efivar);
916 /* It's dead Jim.... */
921 * Let's not leave out systab information that snuck into
924 static ssize_t systab_show(struct kobject *kobj,
925 struct kobj_attribute *attr, char *buf)
932 if (efi.mps != EFI_INVALID_TABLE_ADDR)
933 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
934 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
935 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
936 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
937 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
938 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
939 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
940 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
941 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
942 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
943 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
944 if (efi.uga != EFI_INVALID_TABLE_ADDR)
945 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
950 static struct kobj_attribute efi_attr_systab =
951 __ATTR(systab, 0400, systab_show, NULL);
953 static struct attribute *efi_subsys_attrs[] = {
954 &efi_attr_systab.attr,
955 NULL, /* maybe more in the future? */
958 static struct attribute_group efi_subsys_attr_group = {
959 .attrs = efi_subsys_attrs,
962 static struct kobject *efi_kobj;
965 * efivar_create_sysfs_entry()
967 * variable_name_size = number of bytes required to hold
968 * variable_name (not counting the NULL
969 * character at the end.
970 * efivars->lock is not held on entry or exit.
971 * Returns 1 on failure, 0 on success
974 efivar_create_sysfs_entry(struct efivars *efivars,
975 unsigned long variable_name_size,
976 efi_char16_t *variable_name,
977 efi_guid_t *vendor_guid)
979 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
981 struct efivar_entry *new_efivar;
983 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
984 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
986 if (!short_name || !new_efivar) {
992 new_efivar->efivars = efivars;
993 memcpy(new_efivar->var.VariableName, variable_name,
995 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
997 /* Convert Unicode to normal chars (assume top bits are 0),
999 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1000 short_name[i] = variable_name[i] & 0xFF;
1002 /* This is ugly, but necessary to separate one vendor's
1003 private variables from another's. */
1005 *(short_name + strlen(short_name)) = '-';
1006 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1008 new_efivar->kobj.kset = efivars->kset;
1009 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1017 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1021 spin_lock(&efivars->lock);
1022 list_add(&new_efivar->list, &efivars->list);
1023 spin_unlock(&efivars->lock);
1029 create_efivars_bin_attributes(struct efivars *efivars)
1031 struct bin_attribute *attr;
1035 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1039 attr->attr.name = "new_var";
1040 attr->attr.mode = 0200;
1041 attr->write = efivar_create;
1042 attr->private = efivars;
1043 efivars->new_var = attr;
1046 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1051 attr->attr.name = "del_var";
1052 attr->attr.mode = 0200;
1053 attr->write = efivar_delete;
1054 attr->private = efivars;
1055 efivars->del_var = attr;
1057 sysfs_bin_attr_init(efivars->new_var);
1058 sysfs_bin_attr_init(efivars->del_var);
1061 error = sysfs_create_bin_file(&efivars->kset->kobj,
1064 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1065 " due to error %d\n", error);
1068 error = sysfs_create_bin_file(&efivars->kset->kobj,
1071 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1072 " due to error %d\n", error);
1073 sysfs_remove_bin_file(&efivars->kset->kobj,
1080 kfree(efivars->del_var);
1081 efivars->del_var = NULL;
1082 kfree(efivars->new_var);
1083 efivars->new_var = NULL;
1087 void unregister_efivars(struct efivars *efivars)
1089 struct efivar_entry *entry, *n;
1091 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1092 spin_lock(&efivars->lock);
1093 list_del(&entry->list);
1094 spin_unlock(&efivars->lock);
1095 efivar_unregister(entry);
1097 if (efivars->new_var)
1098 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1099 if (efivars->del_var)
1100 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1101 kfree(efivars->new_var);
1102 kfree(efivars->del_var);
1103 kset_unregister(efivars->kset);
1105 EXPORT_SYMBOL_GPL(unregister_efivars);
1107 int register_efivars(struct efivars *efivars,
1108 const struct efivar_operations *ops,
1109 struct kobject *parent_kobj)
1111 efi_status_t status = EFI_NOT_FOUND;
1112 efi_guid_t vendor_guid;
1113 efi_char16_t *variable_name;
1114 unsigned long variable_name_size = 1024;
1117 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1118 if (!variable_name) {
1119 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1123 spin_lock_init(&efivars->lock);
1124 INIT_LIST_HEAD(&efivars->list);
1127 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1128 if (!efivars->kset) {
1129 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1135 * Per EFI spec, the maximum storage allocated for both
1136 * the variable name and variable data is 1024 bytes.
1140 variable_name_size = 1024;
1142 status = ops->get_next_variable(&variable_name_size,
1147 efivar_create_sysfs_entry(efivars,
1155 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1157 status = EFI_NOT_FOUND;
1160 } while (status != EFI_NOT_FOUND);
1162 error = create_efivars_bin_attributes(efivars);
1164 unregister_efivars(efivars);
1166 efivars->efi_pstore_info = efi_pstore_info;
1168 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1169 if (efivars->efi_pstore_info.buf) {
1170 efivars->efi_pstore_info.bufsize = 1024;
1171 efivars->efi_pstore_info.data = efivars;
1172 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1173 pstore_register(&efivars->efi_pstore_info);
1177 kfree(variable_name);
1181 EXPORT_SYMBOL_GPL(register_efivars);
1183 static struct efivars __efivars;
1184 static struct efivar_operations ops;
1187 * For now we register the efi subsystem with the firmware subsystem
1188 * and the vars subsystem with the efi subsystem. In the future, it
1189 * might make sense to split off the efi subsystem into its own
1190 * driver, but for now only efivars will register with it, so just
1199 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1205 /* For now we'll register the efi directory at /sys/firmware/efi */
1206 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1208 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1212 ops.get_variable = efi.get_variable;
1213 ops.set_variable = efi.set_variable;
1214 ops.get_next_variable = efi.get_next_variable;
1215 error = register_efivars(&__efivars, &ops, efi_kobj);
1219 /* Don't forget the systab entry */
1220 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1223 "efivars: Sysfs attribute export failed with error %d.\n",
1225 goto err_unregister;
1231 unregister_efivars(&__efivars);
1233 kobject_put(efi_kobj);
1241 unregister_efivars(&__efivars);
1242 kobject_put(efi_kobj);
1246 module_init(efivars_init);
1247 module_exit(efivars_exit);