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>
82 #include <linux/ctype.h>
85 #include <linux/ramfs.h>
86 #include <linux/pagemap.h>
88 #include <asm/uaccess.h>
90 #define EFIVARS_VERSION "0.08"
91 #define EFIVARS_DATE "2004-May-17"
93 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
94 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
95 MODULE_LICENSE("GPL");
96 MODULE_VERSION(EFIVARS_VERSION);
98 #define DUMP_NAME_LEN 52
101 * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
102 * not including trailing NUL
106 static bool efivars_pstore_disable =
107 IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
109 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
112 * The maximum size of VariableName + Data = 1024
113 * Therefore, it's reasonable to save that much
114 * space in each part of the structure,
115 * and we use a page for reading/writing.
118 struct efi_variable {
119 efi_char16_t VariableName[1024/sizeof(efi_char16_t)];
120 efi_guid_t VendorGuid;
121 unsigned long DataSize;
125 } __attribute__((packed));
127 struct efivar_entry {
128 struct efivars *efivars;
129 struct efi_variable var;
130 struct list_head list;
134 struct efivar_attribute {
135 struct attribute attr;
136 ssize_t (*show) (struct efivar_entry *entry, char *buf);
137 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
140 static struct efivars __efivars;
141 static struct efivar_operations ops;
143 #define PSTORE_EFI_ATTRIBUTES \
144 (EFI_VARIABLE_NON_VOLATILE | \
145 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
146 EFI_VARIABLE_RUNTIME_ACCESS)
148 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
149 struct efivar_attribute efivar_attr_##_name = { \
150 .attr = {.name = __stringify(_name), .mode = _mode}, \
155 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
156 #define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
159 * Prototype for sysfs creation function
162 efivar_create_sysfs_entry(struct efivars *efivars,
163 unsigned long variable_name_size,
164 efi_char16_t *variable_name,
165 efi_guid_t *vendor_guid);
168 * Prototype for workqueue functions updating sysfs entry
171 static void efivar_update_sysfs_entries(struct work_struct *);
172 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
173 static bool efivar_wq_enabled = true;
176 * Return the number of bytes is the length of this string
177 * Note: this is NOT the same as the number of unicode characters
179 static inline unsigned long
180 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
182 return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
186 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
195 if (*a == 0) /* implies *b == 0 */
204 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
207 struct efi_generic_dev_path *node;
210 node = (struct efi_generic_dev_path *)buffer;
212 if (len < sizeof(*node))
215 while (offset <= len - sizeof(*node) &&
216 node->length >= sizeof(*node) &&
217 node->length <= len - offset) {
218 offset += node->length;
220 if ((node->type == EFI_DEV_END_PATH ||
221 node->type == EFI_DEV_END_PATH2) &&
222 node->sub_type == EFI_DEV_END_ENTIRE)
225 node = (struct efi_generic_dev_path *)(buffer + offset);
229 * If we're here then either node->length pointed past the end
230 * of the buffer or we reached the end of the buffer without
231 * finding a device path end node.
237 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
240 /* An array of 16-bit integers */
248 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
252 int i, desclength = 0, namelen;
254 namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
256 /* Either "Boot" or "Driver" followed by four digits of hex */
257 for (i = match; i < match+4; i++) {
258 if (var->VariableName[i] > 127 ||
259 hex_to_bin(var->VariableName[i] & 0xff) < 0)
263 /* Reject it if there's 4 digits of hex and then further content */
264 if (namelen > match + 4)
267 /* A valid entry must be at least 8 bytes */
271 filepathlength = buffer[4] | buffer[5] << 8;
274 * There's no stored length for the description, so it has to be
277 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
279 /* Each boot entry must have a descriptor */
284 * If the sum of the length of the description, the claimed filepath
285 * length and the original header are greater than the length of the
286 * variable, it's malformed
288 if ((desclength + filepathlength + 6) > len)
292 * And, finally, check the filepath
294 return validate_device_path(var, match, buffer + desclength + 6,
299 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
302 /* A single 16-bit integer */
310 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
315 for (i = 0; i < len; i++) {
326 struct variable_validate {
328 bool (*validate)(struct efi_variable *var, int match, u8 *data,
332 static const struct variable_validate variable_validate[] = {
333 { "BootNext", validate_uint16 },
334 { "BootOrder", validate_boot_order },
335 { "DriverOrder", validate_boot_order },
336 { "Boot*", validate_load_option },
337 { "Driver*", validate_load_option },
338 { "ConIn", validate_device_path },
339 { "ConInDev", validate_device_path },
340 { "ConOut", validate_device_path },
341 { "ConOutDev", validate_device_path },
342 { "ErrOut", validate_device_path },
343 { "ErrOutDev", validate_device_path },
344 { "Timeout", validate_uint16 },
345 { "Lang", validate_ascii_string },
346 { "PlatformLang", validate_ascii_string },
351 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
354 u16 *unicode_name = var->VariableName;
356 for (i = 0; variable_validate[i].validate != NULL; i++) {
357 const char *name = variable_validate[i].name;
360 for (match = 0; ; match++) {
361 char c = name[match];
362 u16 u = unicode_name[match];
364 /* All special variables are plain ascii */
368 /* Wildcard in the matching name means we've matched */
370 return variable_validate[i].validate(var,
373 /* Case sensitive match */
377 /* Reached the end of the string while matching */
379 return variable_validate[i].validate(var,
388 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
392 var->DataSize = 1024;
393 status = efivars->ops->get_variable(var->VariableName,
402 get_var_data(struct efivars *efivars, struct efi_variable *var)
407 spin_lock_irqsave(&efivars->lock, flags);
408 status = get_var_data_locked(efivars, var);
409 spin_unlock_irqrestore(&efivars->lock, flags);
411 if (status != EFI_SUCCESS) {
412 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
419 check_var_size_locked(struct efivars *efivars, u32 attributes,
422 u64 storage_size, remaining_size, max_size;
424 const struct efivar_operations *fops = efivars->ops;
426 if (!efivars->ops->query_variable_info)
427 return EFI_UNSUPPORTED;
429 status = fops->query_variable_info(attributes, &storage_size,
430 &remaining_size, &max_size);
432 if (status != EFI_SUCCESS)
435 if (!storage_size || size > remaining_size || size > max_size ||
436 (remaining_size - size) < (storage_size / 2))
437 return EFI_OUT_OF_RESOURCES;
444 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
449 spin_lock_irqsave(&efivars->lock, flags);
450 status = check_var_size_locked(efivars, attributes, size);
451 spin_unlock_irqrestore(&efivars->lock, flags);
457 efivar_guid_read(struct efivar_entry *entry, char *buf)
459 struct efi_variable *var = &entry->var;
465 efi_guid_unparse(&var->VendorGuid, str);
467 str += sprintf(str, "\n");
473 efivar_attr_read(struct efivar_entry *entry, char *buf)
475 struct efi_variable *var = &entry->var;
482 status = get_var_data(entry->efivars, var);
483 if (status != EFI_SUCCESS)
486 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
487 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
488 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
489 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
490 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
491 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
492 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
493 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
494 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
496 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
497 if (var->Attributes &
498 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
500 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
501 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
502 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
507 efivar_size_read(struct efivar_entry *entry, char *buf)
509 struct efi_variable *var = &entry->var;
516 status = get_var_data(entry->efivars, var);
517 if (status != EFI_SUCCESS)
520 str += sprintf(str, "0x%lx\n", var->DataSize);
525 efivar_data_read(struct efivar_entry *entry, char *buf)
527 struct efi_variable *var = &entry->var;
533 status = get_var_data(entry->efivars, var);
534 if (status != EFI_SUCCESS)
537 memcpy(buf, var->Data, var->DataSize);
538 return var->DataSize;
541 * We allow each variable to be edited via rewriting the
542 * entire efi variable structure.
545 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
547 struct efi_variable *new_var, *var = &entry->var;
548 struct efivars *efivars = entry->efivars;
549 efi_status_t status = EFI_NOT_FOUND;
551 if (count != sizeof(struct efi_variable))
554 new_var = (struct efi_variable *)buf;
556 * If only updating the variable data, then the name
557 * and guid should remain the same
559 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
560 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
561 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
565 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
566 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
570 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
571 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
572 printk(KERN_ERR "efivars: Malformed variable content\n");
576 spin_lock_irq(&efivars->lock);
578 status = check_var_size_locked(efivars, new_var->Attributes,
579 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
581 if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
582 status = efivars->ops->set_variable(new_var->VariableName,
583 &new_var->VendorGuid,
588 spin_unlock_irq(&efivars->lock);
590 if (status != EFI_SUCCESS) {
591 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
596 memcpy(&entry->var, new_var, count);
601 efivar_show_raw(struct efivar_entry *entry, char *buf)
603 struct efi_variable *var = &entry->var;
609 status = get_var_data(entry->efivars, var);
610 if (status != EFI_SUCCESS)
613 memcpy(buf, var, sizeof(*var));
618 * Generic read/write functions that call the specific functions of
621 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
624 struct efivar_entry *var = to_efivar_entry(kobj);
625 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
628 if (!capable(CAP_SYS_ADMIN))
631 if (efivar_attr->show) {
632 ret = efivar_attr->show(var, buf);
637 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
638 const char *buf, size_t count)
640 struct efivar_entry *var = to_efivar_entry(kobj);
641 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
644 if (!capable(CAP_SYS_ADMIN))
647 if (efivar_attr->store)
648 ret = efivar_attr->store(var, buf, count);
653 static const struct sysfs_ops efivar_attr_ops = {
654 .show = efivar_attr_show,
655 .store = efivar_attr_store,
658 static void efivar_release(struct kobject *kobj)
660 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
664 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
665 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
666 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
667 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
668 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
670 static struct attribute *def_attrs[] = {
671 &efivar_attr_guid.attr,
672 &efivar_attr_size.attr,
673 &efivar_attr_attributes.attr,
674 &efivar_attr_data.attr,
675 &efivar_attr_raw_var.attr,
679 static struct kobj_type efivar_ktype = {
680 .release = efivar_release,
681 .sysfs_ops = &efivar_attr_ops,
682 .default_attrs = def_attrs,
686 efivar_unregister(struct efivar_entry *var)
688 kobject_put(&var->kobj);
691 static int efivarfs_file_open(struct inode *inode, struct file *file)
693 file->private_data = inode->i_private;
697 static int efi_status_to_err(efi_status_t status)
702 case EFI_INVALID_PARAMETER:
705 case EFI_OUT_OF_RESOURCES:
708 case EFI_DEVICE_ERROR:
711 case EFI_WRITE_PROTECTED:
714 case EFI_SECURITY_VIOLATION:
727 static ssize_t efivarfs_file_write(struct file *file,
728 const char __user *userbuf, size_t count, loff_t *ppos)
730 struct efivar_entry *var = file->private_data;
731 struct efivars *efivars;
735 struct inode *inode = file->f_mapping->host;
736 unsigned long datasize = count - sizeof(attributes);
737 unsigned long newdatasize, varsize;
740 if (count < sizeof(attributes))
743 if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
746 if (attributes & ~(EFI_VARIABLE_MASK))
749 efivars = var->efivars;
752 * Ensure that the user can't allocate arbitrarily large
753 * amounts of memory. Pick a default size of 64K if
754 * QueryVariableInfo() isn't supported by the firmware.
757 varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
758 status = check_var_size(efivars, attributes, varsize);
760 if (status != EFI_SUCCESS) {
761 if (status != EFI_UNSUPPORTED)
762 return efi_status_to_err(status);
764 if (datasize > 65536)
768 data = kmalloc(datasize, GFP_KERNEL);
772 if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
777 if (validate_var(&var->var, data, datasize) == false) {
783 * The lock here protects the get_variable call, the conditional
784 * set_variable call, and removal of the variable from the efivars
785 * list (in the case of an authenticated delete).
787 spin_lock_irq(&efivars->lock);
790 * Ensure that the available space hasn't shrunk below the safe level
793 status = check_var_size_locked(efivars, attributes, varsize);
795 if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
796 spin_unlock_irq(&efivars->lock);
799 return efi_status_to_err(status);
802 status = efivars->ops->set_variable(var->var.VariableName,
803 &var->var.VendorGuid,
804 attributes, datasize,
807 if (status != EFI_SUCCESS) {
808 spin_unlock_irq(&efivars->lock);
811 return efi_status_to_err(status);
817 * Writing to the variable may have caused a change in size (which
818 * could either be an append or an overwrite), or the variable to be
819 * deleted. Perform a GetVariable() so we can tell what actually
823 status = efivars->ops->get_variable(var->var.VariableName,
824 &var->var.VendorGuid,
828 if (status == EFI_BUFFER_TOO_SMALL) {
829 spin_unlock_irq(&efivars->lock);
830 mutex_lock(&inode->i_mutex);
831 i_size_write(inode, newdatasize + sizeof(attributes));
832 mutex_unlock(&inode->i_mutex);
834 } else if (status == EFI_NOT_FOUND) {
835 list_del(&var->list);
836 spin_unlock_irq(&efivars->lock);
837 efivar_unregister(var);
839 d_delete(file->f_dentry);
840 dput(file->f_dentry);
843 spin_unlock_irq(&efivars->lock);
844 pr_warn("efivarfs: inconsistent EFI variable implementation? "
845 "status = %lx\n", status);
854 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
855 size_t count, loff_t *ppos)
857 struct efivar_entry *var = file->private_data;
858 struct efivars *efivars = var->efivars;
860 unsigned long datasize = 0;
865 spin_lock_irq(&efivars->lock);
866 status = efivars->ops->get_variable(var->var.VariableName,
867 &var->var.VendorGuid,
868 &attributes, &datasize, NULL);
869 spin_unlock_irq(&efivars->lock);
871 if (status != EFI_BUFFER_TOO_SMALL)
872 return efi_status_to_err(status);
874 data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
879 spin_lock_irq(&efivars->lock);
880 status = efivars->ops->get_variable(var->var.VariableName,
881 &var->var.VendorGuid,
882 &attributes, &datasize,
883 (data + sizeof(attributes)));
884 spin_unlock_irq(&efivars->lock);
886 if (status != EFI_SUCCESS) {
887 size = efi_status_to_err(status);
891 memcpy(data, &attributes, sizeof(attributes));
892 size = simple_read_from_buffer(userbuf, count, ppos,
893 data, datasize + sizeof(attributes));
900 static void efivarfs_evict_inode(struct inode *inode)
905 static const struct super_operations efivarfs_ops = {
906 .statfs = simple_statfs,
907 .drop_inode = generic_delete_inode,
908 .evict_inode = efivarfs_evict_inode,
909 .show_options = generic_show_options,
912 static struct super_block *efivarfs_sb;
914 static const struct inode_operations efivarfs_dir_inode_operations;
916 static const struct file_operations efivarfs_file_operations = {
917 .open = efivarfs_file_open,
918 .read = efivarfs_file_read,
919 .write = efivarfs_file_write,
923 static struct inode *efivarfs_get_inode(struct super_block *sb,
924 const struct inode *dir, int mode, dev_t dev)
926 struct inode *inode = new_inode(sb);
929 inode->i_ino = get_next_ino();
930 inode->i_mode = mode;
931 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
932 switch (mode & S_IFMT) {
934 inode->i_fop = &efivarfs_file_operations;
937 inode->i_op = &efivarfs_dir_inode_operations;
938 inode->i_fop = &simple_dir_operations;
947 * Return true if 'str' is a valid efivarfs filename of the form,
949 * VariableName-12345678-1234-1234-1234-1234567891bc
951 static bool efivarfs_valid_name(const char *str, int len)
953 static const char dashes[GUID_LEN] = {
954 [8] = 1, [13] = 1, [18] = 1, [23] = 1
956 const char *s = str + len - GUID_LEN;
960 * We need a GUID, plus at least one letter for the variable name,
961 * plus the '-' separator
963 if (len < GUID_LEN + 2)
966 /* GUID must be preceded by a '-' */
971 * Validate that 's' is of the correct format, e.g.
973 * 12345678-1234-1234-1234-123456789abc
975 for (i = 0; i < GUID_LEN; i++) {
988 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
990 guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
991 guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
992 guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
993 guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
994 guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
995 guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
996 guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
997 guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
998 guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
999 guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1000 guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1001 guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1002 guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1003 guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1004 guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1005 guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1008 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1009 umode_t mode, bool excl)
1011 struct inode *inode;
1012 struct efivars *efivars = &__efivars;
1013 struct efivar_entry *var;
1014 int namelen, i = 0, err = 0;
1016 if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1019 inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1023 var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1029 /* length of the variable name itself: remove GUID and separator */
1030 namelen = dentry->d_name.len - GUID_LEN - 1;
1032 efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1033 &var->var.VendorGuid);
1035 for (i = 0; i < namelen; i++)
1036 var->var.VariableName[i] = dentry->d_name.name[i];
1038 var->var.VariableName[i] = '\0';
1040 inode->i_private = var;
1041 var->efivars = efivars;
1042 var->kobj.kset = efivars->kset;
1044 err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1045 dentry->d_name.name);
1049 kobject_uevent(&var->kobj, KOBJ_ADD);
1050 spin_lock_irq(&efivars->lock);
1051 list_add(&var->list, &efivars->list);
1052 spin_unlock_irq(&efivars->lock);
1053 d_instantiate(dentry, inode);
1063 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1065 struct efivar_entry *var = dentry->d_inode->i_private;
1066 struct efivars *efivars = var->efivars;
1067 efi_status_t status;
1069 spin_lock_irq(&efivars->lock);
1071 status = efivars->ops->set_variable(var->var.VariableName,
1072 &var->var.VendorGuid,
1075 if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1076 list_del(&var->list);
1077 spin_unlock_irq(&efivars->lock);
1078 efivar_unregister(var);
1079 drop_nlink(dentry->d_inode);
1084 spin_unlock_irq(&efivars->lock);
1089 * Compare two efivarfs file names.
1091 * An efivarfs filename is composed of two parts,
1093 * 1. A case-sensitive variable name
1094 * 2. A case-insensitive GUID
1096 * So we need to perform a case-sensitive match on part 1 and a
1097 * case-insensitive match on part 2.
1099 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1100 const struct dentry *dentry, const struct inode *inode,
1101 unsigned int len, const char *str,
1102 const struct qstr *name)
1104 int guid = len - GUID_LEN;
1106 if (name->len != len)
1109 /* Case-sensitive compare for the variable name */
1110 if (memcmp(str, name->name, guid))
1113 /* Case-insensitive compare for the GUID */
1114 return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1117 static int efivarfs_d_hash(const struct dentry *dentry,
1118 const struct inode *inode, struct qstr *qstr)
1120 unsigned long hash = init_name_hash();
1121 const unsigned char *s = qstr->name;
1122 unsigned int len = qstr->len;
1124 if (!efivarfs_valid_name(s, len))
1127 while (len-- > GUID_LEN)
1128 hash = partial_name_hash(*s++, hash);
1130 /* GUID is case-insensitive. */
1132 hash = partial_name_hash(tolower(*s++), hash);
1134 qstr->hash = end_name_hash(hash);
1139 * Retaining negative dentries for an in-memory filesystem just wastes
1140 * memory and lookup time: arrange for them to be deleted immediately.
1142 static int efivarfs_delete_dentry(const struct dentry *dentry)
1147 static struct dentry_operations efivarfs_d_ops = {
1148 .d_compare = efivarfs_d_compare,
1149 .d_hash = efivarfs_d_hash,
1150 .d_delete = efivarfs_delete_dentry,
1153 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1160 q.len = strlen(name);
1162 err = efivarfs_d_hash(NULL, NULL, &q);
1164 return ERR_PTR(err);
1166 d = d_alloc(parent, &q);
1170 return ERR_PTR(-ENOMEM);
1173 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1175 struct inode *inode = NULL;
1176 struct dentry *root;
1177 struct efivar_entry *entry, *n;
1178 struct efivars *efivars = &__efivars;
1184 sb->s_maxbytes = MAX_LFS_FILESIZE;
1185 sb->s_blocksize = PAGE_CACHE_SIZE;
1186 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1187 sb->s_magic = EFIVARFS_MAGIC;
1188 sb->s_op = &efivarfs_ops;
1189 sb->s_d_op = &efivarfs_d_ops;
1190 sb->s_time_gran = 1;
1192 inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1195 inode->i_op = &efivarfs_dir_inode_operations;
1197 root = d_make_root(inode);
1202 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1203 struct dentry *dentry, *root = efivarfs_sb->s_root;
1204 unsigned long size = 0;
1209 len = utf16_strlen(entry->var.VariableName);
1211 /* name, plus '-', plus GUID, plus NUL*/
1212 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1216 for (i = 0; i < len; i++)
1217 name[i] = entry->var.VariableName[i] & 0xFF;
1221 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1223 name[len+GUID_LEN+1] = '\0';
1225 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1230 dentry = efivarfs_alloc_dentry(root, name);
1231 if (IS_ERR(dentry)) {
1232 err = PTR_ERR(dentry);
1236 /* copied by the above to local storage in the dentry. */
1239 spin_lock_irq(&efivars->lock);
1240 efivars->ops->get_variable(entry->var.VariableName,
1241 &entry->var.VendorGuid,
1242 &entry->var.Attributes,
1245 spin_unlock_irq(&efivars->lock);
1247 mutex_lock(&inode->i_mutex);
1248 inode->i_private = entry;
1249 i_size_write(inode, size + sizeof(entry->var.Attributes));
1250 mutex_unlock(&inode->i_mutex);
1251 d_add(dentry, inode);
1264 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1265 int flags, const char *dev_name, void *data)
1267 return mount_single(fs_type, flags, data, efivarfs_fill_super);
1270 static void efivarfs_kill_sb(struct super_block *sb)
1272 kill_litter_super(sb);
1276 static struct file_system_type efivarfs_type = {
1278 .mount = efivarfs_mount,
1279 .kill_sb = efivarfs_kill_sb,
1281 MODULE_ALIAS_FS("efivarfs");
1284 * Handle negative dentry.
1286 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1289 if (dentry->d_name.len > NAME_MAX)
1290 return ERR_PTR(-ENAMETOOLONG);
1291 d_add(dentry, NULL);
1295 static const struct inode_operations efivarfs_dir_inode_operations = {
1296 .lookup = efivarfs_lookup,
1297 .unlink = efivarfs_unlink,
1298 .create = efivarfs_create,
1301 #ifdef CONFIG_EFI_VARS_PSTORE
1303 static int efi_pstore_open(struct pstore_info *psi)
1305 struct efivars *efivars = psi->data;
1307 spin_lock_irq(&efivars->lock);
1308 efivars->walk_entry = list_first_entry(&efivars->list,
1309 struct efivar_entry, list);
1313 static int efi_pstore_close(struct pstore_info *psi)
1315 struct efivars *efivars = psi->data;
1317 spin_unlock_irq(&efivars->lock);
1321 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1322 int *count, struct timespec *timespec,
1323 char **buf, struct pstore_info *psi)
1325 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1326 struct efivars *efivars = psi->data;
1327 char name[DUMP_NAME_LEN];
1330 unsigned int part, size;
1333 while (&efivars->walk_entry->list != &efivars->list) {
1334 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1336 for (i = 0; i < DUMP_NAME_LEN; i++) {
1337 name[i] = efivars->walk_entry->var.VariableName[i];
1339 if (sscanf(name, "dump-type%u-%u-%d-%lu",
1340 type, &part, &cnt, &time) == 4) {
1343 timespec->tv_sec = time;
1344 timespec->tv_nsec = 0;
1345 } else if (sscanf(name, "dump-type%u-%u-%lu",
1346 type, &part, &time) == 3) {
1348 * Check if an old format,
1349 * which doesn't support holding
1350 * multiple logs, remains.
1354 timespec->tv_sec = time;
1355 timespec->tv_nsec = 0;
1357 efivars->walk_entry = list_entry(
1358 efivars->walk_entry->list.next,
1359 struct efivar_entry, list);
1363 get_var_data_locked(efivars, &efivars->walk_entry->var);
1364 size = efivars->walk_entry->var.DataSize;
1365 *buf = kmalloc(size, GFP_KERNEL);
1368 memcpy(*buf, efivars->walk_entry->var.Data,
1370 efivars->walk_entry = list_entry(
1371 efivars->walk_entry->list.next,
1372 struct efivar_entry, list);
1375 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1376 struct efivar_entry, list);
1381 static int efi_pstore_write(enum pstore_type_id type,
1382 enum kmsg_dump_reason reason, u64 *id,
1383 unsigned int part, int count, size_t size,
1384 struct pstore_info *psi)
1386 char name[DUMP_NAME_LEN];
1387 efi_char16_t efi_name[DUMP_NAME_LEN];
1388 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1389 struct efivars *efivars = psi->data;
1391 efi_status_t status = EFI_NOT_FOUND;
1392 unsigned long flags;
1394 if (pstore_cannot_block_path(reason)) {
1396 * If the lock is taken by another cpu in non-blocking path,
1397 * this driver returns without entering firmware to avoid
1400 if (!spin_trylock_irqsave(&efivars->lock, flags))
1403 spin_lock_irqsave(&efivars->lock, flags);
1406 * Check if there is a space enough to log.
1407 * size: a size of logging data
1408 * DUMP_NAME_LEN * 2: a maximum size of variable name
1411 status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1412 size + DUMP_NAME_LEN * 2);
1415 spin_unlock_irqrestore(&efivars->lock, flags);
1420 sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1423 for (i = 0; i < DUMP_NAME_LEN; i++)
1424 efi_name[i] = name[i];
1426 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1429 spin_unlock_irqrestore(&efivars->lock, flags);
1431 if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
1432 schedule_work(&efivar_work);
1438 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1439 struct timespec time, struct pstore_info *psi)
1441 char name[DUMP_NAME_LEN];
1442 efi_char16_t efi_name[DUMP_NAME_LEN];
1443 char name_old[DUMP_NAME_LEN];
1444 efi_char16_t efi_name_old[DUMP_NAME_LEN];
1445 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1446 struct efivars *efivars = psi->data;
1447 struct efivar_entry *entry, *found = NULL;
1450 sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1453 spin_lock_irq(&efivars->lock);
1455 for (i = 0; i < DUMP_NAME_LEN; i++)
1456 efi_name[i] = name[i];
1459 * Clean up an entry with the same name
1462 list_for_each_entry(entry, &efivars->list, list) {
1463 get_var_data_locked(efivars, &entry->var);
1465 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1467 if (utf16_strncmp(entry->var.VariableName, efi_name,
1468 utf16_strlen(efi_name))) {
1470 * Check if an old format,
1471 * which doesn't support holding
1472 * multiple logs, remains.
1474 sprintf(name_old, "dump-type%u-%u-%lu", type,
1475 (unsigned int)id, time.tv_sec);
1477 for (i = 0; i < DUMP_NAME_LEN; i++)
1478 efi_name_old[i] = name_old[i];
1480 if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1481 utf16_strlen(efi_name_old)))
1487 efivars->ops->set_variable(entry->var.VariableName,
1488 &entry->var.VendorGuid,
1489 PSTORE_EFI_ATTRIBUTES,
1495 list_del(&found->list);
1497 spin_unlock_irq(&efivars->lock);
1500 efivar_unregister(found);
1505 static struct pstore_info efi_pstore_info = {
1506 .owner = THIS_MODULE,
1508 .open = efi_pstore_open,
1509 .close = efi_pstore_close,
1510 .read = efi_pstore_read,
1511 .write = efi_pstore_write,
1512 .erase = efi_pstore_erase,
1515 static void efivar_pstore_register(struct efivars *efivars)
1517 efivars->efi_pstore_info = efi_pstore_info;
1518 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1519 if (efivars->efi_pstore_info.buf) {
1520 efivars->efi_pstore_info.bufsize = 1024;
1521 efivars->efi_pstore_info.data = efivars;
1522 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1523 pstore_register(&efivars->efi_pstore_info);
1527 static void efivar_pstore_register(struct efivars *efivars)
1533 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1534 struct bin_attribute *bin_attr,
1535 char *buf, loff_t pos, size_t count)
1537 struct efi_variable *new_var = (struct efi_variable *)buf;
1538 struct efivars *efivars = bin_attr->private;
1539 struct efivar_entry *search_efivar, *n;
1540 unsigned long strsize1, strsize2;
1541 efi_status_t status = EFI_NOT_FOUND;
1544 if (!capable(CAP_SYS_ADMIN))
1547 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1548 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1549 printk(KERN_ERR "efivars: Malformed variable content\n");
1553 spin_lock_irq(&efivars->lock);
1556 * Does this variable already exist?
1558 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1559 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1560 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1561 if (strsize1 == strsize2 &&
1562 !memcmp(&(search_efivar->var.VariableName),
1563 new_var->VariableName, strsize1) &&
1564 !efi_guidcmp(search_efivar->var.VendorGuid,
1565 new_var->VendorGuid)) {
1571 spin_unlock_irq(&efivars->lock);
1575 status = check_var_size_locked(efivars, new_var->Attributes,
1576 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
1578 if (status && status != EFI_UNSUPPORTED) {
1579 spin_unlock_irq(&efivars->lock);
1580 return efi_status_to_err(status);
1583 /* now *really* create the variable via EFI */
1584 status = efivars->ops->set_variable(new_var->VariableName,
1585 &new_var->VendorGuid,
1586 new_var->Attributes,
1590 if (status != EFI_SUCCESS) {
1591 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1593 spin_unlock_irq(&efivars->lock);
1596 spin_unlock_irq(&efivars->lock);
1598 /* Create the entry in sysfs. Locking is not required here */
1599 status = efivar_create_sysfs_entry(efivars,
1600 utf16_strsize(new_var->VariableName,
1602 new_var->VariableName,
1603 &new_var->VendorGuid);
1605 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1610 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1611 struct bin_attribute *bin_attr,
1612 char *buf, loff_t pos, size_t count)
1614 struct efi_variable *del_var = (struct efi_variable *)buf;
1615 struct efivars *efivars = bin_attr->private;
1616 struct efivar_entry *search_efivar, *n;
1617 unsigned long strsize1, strsize2;
1618 efi_status_t status = EFI_NOT_FOUND;
1621 if (!capable(CAP_SYS_ADMIN))
1624 spin_lock_irq(&efivars->lock);
1627 * Does this variable already exist?
1629 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1630 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1631 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1632 if (strsize1 == strsize2 &&
1633 !memcmp(&(search_efivar->var.VariableName),
1634 del_var->VariableName, strsize1) &&
1635 !efi_guidcmp(search_efivar->var.VendorGuid,
1636 del_var->VendorGuid)) {
1642 spin_unlock_irq(&efivars->lock);
1645 /* force the Attributes/DataSize to 0 to ensure deletion */
1646 del_var->Attributes = 0;
1647 del_var->DataSize = 0;
1649 status = efivars->ops->set_variable(del_var->VariableName,
1650 &del_var->VendorGuid,
1651 del_var->Attributes,
1655 if (status != EFI_SUCCESS) {
1656 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1658 spin_unlock_irq(&efivars->lock);
1661 list_del(&search_efivar->list);
1662 /* We need to release this lock before unregistering. */
1663 spin_unlock_irq(&efivars->lock);
1664 efivar_unregister(search_efivar);
1666 /* It's dead Jim.... */
1670 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1672 struct efivar_entry *entry, *n;
1673 struct efivars *efivars = &__efivars;
1674 unsigned long strsize1, strsize2;
1677 strsize1 = utf16_strsize(variable_name, 1024);
1678 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1679 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1680 if (strsize1 == strsize2 &&
1681 !memcmp(variable_name, &(entry->var.VariableName),
1683 !efi_guidcmp(entry->var.VendorGuid,
1693 * Returns the size of variable_name, in bytes, including the
1694 * terminating NULL character, or variable_name_size if no NULL
1695 * character is found among the first variable_name_size bytes.
1697 static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1698 unsigned long variable_name_size)
1704 * The variable name is, by definition, a NULL-terminated
1705 * string, so make absolutely sure that variable_name_size is
1706 * the value we expect it to be. If not, return the real size.
1708 for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1709 c = variable_name[(len / sizeof(c)) - 1];
1714 return min(len, variable_name_size);
1717 static void efivar_update_sysfs_entries(struct work_struct *work)
1719 struct efivars *efivars = &__efivars;
1721 efi_char16_t *variable_name;
1722 unsigned long variable_name_size = 1024;
1723 efi_status_t status = EFI_NOT_FOUND;
1726 /* Add new sysfs entries */
1728 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1729 if (!variable_name) {
1730 pr_err("efivars: Memory allocation failed.\n");
1734 spin_lock_irq(&efivars->lock);
1737 variable_name_size = 1024;
1738 status = efivars->ops->get_next_variable(
1739 &variable_name_size,
1742 if (status != EFI_SUCCESS) {
1745 if (!variable_is_present(variable_name,
1752 spin_unlock_irq(&efivars->lock);
1755 kfree(variable_name);
1758 variable_name_size = var_name_strnsize(variable_name,
1759 variable_name_size);
1760 efivar_create_sysfs_entry(efivars,
1762 variable_name, &vendor);
1768 * Let's not leave out systab information that snuck into
1769 * the efivars driver
1771 static ssize_t systab_show(struct kobject *kobj,
1772 struct kobj_attribute *attr, char *buf)
1779 if (efi.mps != EFI_INVALID_TABLE_ADDR)
1780 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1781 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1782 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1783 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1784 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1785 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1786 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1787 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1788 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1789 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1790 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1791 if (efi.uga != EFI_INVALID_TABLE_ADDR)
1792 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1797 static struct kobj_attribute efi_attr_systab =
1798 __ATTR(systab, 0400, systab_show, NULL);
1800 static struct attribute *efi_subsys_attrs[] = {
1801 &efi_attr_systab.attr,
1802 NULL, /* maybe more in the future? */
1805 static struct attribute_group efi_subsys_attr_group = {
1806 .attrs = efi_subsys_attrs,
1809 static struct kobject *efi_kobj;
1812 * efivar_create_sysfs_entry()
1814 * variable_name_size = number of bytes required to hold
1815 * variable_name (not counting the NULL
1816 * character at the end.
1817 * efivars->lock is not held on entry or exit.
1818 * Returns 1 on failure, 0 on success
1821 efivar_create_sysfs_entry(struct efivars *efivars,
1822 unsigned long variable_name_size,
1823 efi_char16_t *variable_name,
1824 efi_guid_t *vendor_guid)
1826 int i, short_name_size;
1828 struct efivar_entry *new_efivar;
1831 * Length of the variable bytes in ASCII, plus the '-' separator,
1832 * plus the GUID, plus trailing NUL
1834 short_name_size = variable_name_size / sizeof(efi_char16_t)
1837 short_name = kzalloc(short_name_size, GFP_KERNEL);
1838 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1840 if (!short_name || !new_efivar) {
1846 new_efivar->efivars = efivars;
1847 memcpy(new_efivar->var.VariableName, variable_name,
1848 variable_name_size);
1849 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1851 /* Convert Unicode to normal chars (assume top bits are 0),
1853 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1854 short_name[i] = variable_name[i] & 0xFF;
1856 /* This is ugly, but necessary to separate one vendor's
1857 private variables from another's. */
1859 *(short_name + strlen(short_name)) = '-';
1860 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1862 new_efivar->kobj.kset = efivars->kset;
1863 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1871 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1875 spin_lock_irq(&efivars->lock);
1876 list_add(&new_efivar->list, &efivars->list);
1877 spin_unlock_irq(&efivars->lock);
1883 create_efivars_bin_attributes(struct efivars *efivars)
1885 struct bin_attribute *attr;
1889 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1893 attr->attr.name = "new_var";
1894 attr->attr.mode = 0200;
1895 attr->write = efivar_create;
1896 attr->private = efivars;
1897 efivars->new_var = attr;
1900 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1905 attr->attr.name = "del_var";
1906 attr->attr.mode = 0200;
1907 attr->write = efivar_delete;
1908 attr->private = efivars;
1909 efivars->del_var = attr;
1911 sysfs_bin_attr_init(efivars->new_var);
1912 sysfs_bin_attr_init(efivars->del_var);
1915 error = sysfs_create_bin_file(&efivars->kset->kobj,
1918 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1919 " due to error %d\n", error);
1922 error = sysfs_create_bin_file(&efivars->kset->kobj,
1925 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1926 " due to error %d\n", error);
1927 sysfs_remove_bin_file(&efivars->kset->kobj,
1934 kfree(efivars->del_var);
1935 efivars->del_var = NULL;
1936 kfree(efivars->new_var);
1937 efivars->new_var = NULL;
1941 void unregister_efivars(struct efivars *efivars)
1943 struct efivar_entry *entry, *n;
1945 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1946 spin_lock_irq(&efivars->lock);
1947 list_del(&entry->list);
1948 spin_unlock_irq(&efivars->lock);
1949 efivar_unregister(entry);
1951 if (efivars->new_var)
1952 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1953 if (efivars->del_var)
1954 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1955 kfree(efivars->new_var);
1956 kfree(efivars->del_var);
1957 kobject_put(efivars->kobject);
1958 kset_unregister(efivars->kset);
1960 EXPORT_SYMBOL_GPL(unregister_efivars);
1963 * Print a warning when duplicate EFI variables are encountered and
1964 * disable the sysfs workqueue since the firmware is buggy.
1966 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1967 unsigned long len16)
1969 size_t i, len8 = len16 / sizeof(efi_char16_t);
1973 * Disable the workqueue since the algorithm it uses for
1974 * detecting new variables won't work with this buggy
1975 * implementation of GetNextVariableName().
1977 efivar_wq_enabled = false;
1979 s8 = kzalloc(len8, GFP_KERNEL);
1983 for (i = 0; i < len8; i++)
1986 printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
1991 int register_efivars(struct efivars *efivars,
1992 const struct efivar_operations *ops,
1993 struct kobject *parent_kobj)
1995 efi_status_t status = EFI_NOT_FOUND;
1996 efi_guid_t vendor_guid;
1997 efi_char16_t *variable_name;
1998 unsigned long variable_name_size = 1024;
2001 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
2002 if (!variable_name) {
2003 printk(KERN_ERR "efivars: Memory allocation failed.\n");
2007 spin_lock_init(&efivars->lock);
2008 INIT_LIST_HEAD(&efivars->list);
2011 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
2012 if (!efivars->kset) {
2013 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
2018 efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
2019 if (!efivars->kobject) {
2020 pr_err("efivars: Subsystem registration failed.\n");
2022 kset_unregister(efivars->kset);
2027 * Per EFI spec, the maximum storage allocated for both
2028 * the variable name and variable data is 1024 bytes.
2032 variable_name_size = 1024;
2034 status = ops->get_next_variable(&variable_name_size,
2039 variable_name_size = var_name_strnsize(variable_name,
2040 variable_name_size);
2043 * Some firmware implementations return the
2044 * same variable name on multiple calls to
2045 * get_next_variable(). Terminate the loop
2046 * immediately as there is no guarantee that
2047 * we'll ever see a different variable name,
2048 * and may end up looping here forever.
2050 if (variable_is_present(variable_name, &vendor_guid)) {
2051 dup_variable_bug(variable_name, &vendor_guid,
2052 variable_name_size);
2053 status = EFI_NOT_FOUND;
2057 efivar_create_sysfs_entry(efivars,
2065 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
2067 status = EFI_NOT_FOUND;
2070 } while (status != EFI_NOT_FOUND);
2072 error = create_efivars_bin_attributes(efivars);
2074 unregister_efivars(efivars);
2076 if (!efivars_pstore_disable)
2077 efivar_pstore_register(efivars);
2079 register_filesystem(&efivarfs_type);
2082 kfree(variable_name);
2086 EXPORT_SYMBOL_GPL(register_efivars);
2089 * For now we register the efi subsystem with the firmware subsystem
2090 * and the vars subsystem with the efi subsystem. In the future, it
2091 * might make sense to split off the efi subsystem into its own
2092 * driver, but for now only efivars will register with it, so just
2101 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2104 if (!efi_enabled(EFI_RUNTIME_SERVICES))
2107 /* For now we'll register the efi directory at /sys/firmware/efi */
2108 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2110 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2114 ops.get_variable = efi.get_variable;
2115 ops.set_variable = efi.set_variable;
2116 ops.get_next_variable = efi.get_next_variable;
2117 ops.query_variable_info = efi.query_variable_info;
2119 error = register_efivars(&__efivars, &ops, efi_kobj);
2123 /* Don't forget the systab entry */
2124 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2127 "efivars: Sysfs attribute export failed with error %d.\n",
2129 goto err_unregister;
2135 unregister_efivars(&__efivars);
2137 kobject_put(efi_kobj);
2144 cancel_work_sync(&efivar_work);
2146 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2147 unregister_efivars(&__efivars);
2148 kobject_put(efi_kobj);
2152 module_init(efivars_init);
2153 module_exit(efivars_exit);