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
95 static bool efivars_pstore_disable =
96 IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
98 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
101 * The maximum size of VariableName + Data = 1024
102 * Therefore, it's reasonable to save that much
103 * space in each part of the structure,
104 * and we use a page for reading/writing.
107 struct efi_variable {
108 efi_char16_t VariableName[1024/sizeof(efi_char16_t)];
109 efi_guid_t VendorGuid;
110 unsigned long DataSize;
114 } __attribute__((packed));
117 struct efivar_entry {
118 struct efivars *efivars;
119 struct efi_variable var;
120 struct list_head list;
124 struct efivar_attribute {
125 struct attribute attr;
126 ssize_t (*show) (struct efivar_entry *entry, char *buf);
127 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
130 static struct efivars __efivars;
132 #define PSTORE_EFI_ATTRIBUTES \
133 (EFI_VARIABLE_NON_VOLATILE | \
134 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
135 EFI_VARIABLE_RUNTIME_ACCESS)
137 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
138 struct efivar_attribute efivar_attr_##_name = { \
139 .attr = {.name = __stringify(_name), .mode = _mode}, \
144 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
145 #define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
148 * Prototype for sysfs creation function
151 efivar_create_sysfs_entry(struct efivars *efivars,
152 unsigned long variable_name_size,
153 efi_char16_t *variable_name,
154 efi_guid_t *vendor_guid);
157 * Prototype for workqueue functions updating sysfs entry
160 static void efivar_update_sysfs_entries(struct work_struct *);
161 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
162 static bool efivar_wq_enabled = true;
164 /* Return the number of unicode characters in data */
166 utf16_strnlen(efi_char16_t *s, size_t maxlength)
168 unsigned long length = 0;
170 while (*s++ != 0 && length < maxlength)
175 static inline unsigned long
176 utf16_strlen(efi_char16_t *s)
178 return utf16_strnlen(s, ~0UL);
182 * Return the number of bytes is the length of this string
183 * Note: this is NOT the same as the number of unicode characters
185 static inline unsigned long
186 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
188 return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
192 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
201 if (*a == 0) /* implies *b == 0 */
210 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
213 struct efi_generic_dev_path *node;
216 node = (struct efi_generic_dev_path *)buffer;
218 if (len < sizeof(*node))
221 while (offset <= len - sizeof(*node) &&
222 node->length >= sizeof(*node) &&
223 node->length <= len - offset) {
224 offset += node->length;
226 if ((node->type == EFI_DEV_END_PATH ||
227 node->type == EFI_DEV_END_PATH2) &&
228 node->sub_type == EFI_DEV_END_ENTIRE)
231 node = (struct efi_generic_dev_path *)(buffer + offset);
235 * If we're here then either node->length pointed past the end
236 * of the buffer or we reached the end of the buffer without
237 * finding a device path end node.
243 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
246 /* An array of 16-bit integers */
254 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
258 int i, desclength = 0, namelen;
260 namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
262 /* Either "Boot" or "Driver" followed by four digits of hex */
263 for (i = match; i < match+4; i++) {
264 if (var->VariableName[i] > 127 ||
265 hex_to_bin(var->VariableName[i] & 0xff) < 0)
269 /* Reject it if there's 4 digits of hex and then further content */
270 if (namelen > match + 4)
273 /* A valid entry must be at least 8 bytes */
277 filepathlength = buffer[4] | buffer[5] << 8;
280 * There's no stored length for the description, so it has to be
283 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
285 /* Each boot entry must have a descriptor */
290 * If the sum of the length of the description, the claimed filepath
291 * length and the original header are greater than the length of the
292 * variable, it's malformed
294 if ((desclength + filepathlength + 6) > len)
298 * And, finally, check the filepath
300 return validate_device_path(var, match, buffer + desclength + 6,
305 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
308 /* A single 16-bit integer */
316 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
321 for (i = 0; i < len; i++) {
332 struct variable_validate {
334 bool (*validate)(struct efi_variable *var, int match, u8 *data,
338 static const struct variable_validate variable_validate[] = {
339 { "BootNext", validate_uint16 },
340 { "BootOrder", validate_boot_order },
341 { "DriverOrder", validate_boot_order },
342 { "Boot*", validate_load_option },
343 { "Driver*", validate_load_option },
344 { "ConIn", validate_device_path },
345 { "ConInDev", validate_device_path },
346 { "ConOut", validate_device_path },
347 { "ConOutDev", validate_device_path },
348 { "ErrOut", validate_device_path },
349 { "ErrOutDev", validate_device_path },
350 { "Timeout", validate_uint16 },
351 { "Lang", validate_ascii_string },
352 { "PlatformLang", validate_ascii_string },
357 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
360 u16 *unicode_name = var->VariableName;
362 for (i = 0; variable_validate[i].validate != NULL; i++) {
363 const char *name = variable_validate[i].name;
366 for (match = 0; ; match++) {
367 char c = name[match];
368 u16 u = unicode_name[match];
370 /* All special variables are plain ascii */
374 /* Wildcard in the matching name means we've matched */
376 return variable_validate[i].validate(var,
379 /* Case sensitive match */
383 /* Reached the end of the string while matching */
385 return variable_validate[i].validate(var,
394 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
398 var->DataSize = 1024;
399 status = efivars->ops->get_variable(var->VariableName,
408 get_var_data(struct efivars *efivars, struct efi_variable *var)
413 spin_lock_irqsave(&efivars->lock, flags);
414 status = get_var_data_locked(efivars, var);
415 spin_unlock_irqrestore(&efivars->lock, flags);
417 if (status != EFI_SUCCESS) {
418 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
425 check_var_size_locked(struct efivars *efivars, u32 attributes,
428 const struct efivar_operations *fops = efivars->ops;
430 if (!efivars->ops->query_variable_store)
431 return EFI_UNSUPPORTED;
433 return fops->query_variable_store(attributes, size);
437 efivar_guid_read(struct efivar_entry *entry, char *buf)
439 struct efi_variable *var = &entry->var;
445 efi_guid_unparse(&var->VendorGuid, str);
447 str += sprintf(str, "\n");
453 efivar_attr_read(struct efivar_entry *entry, char *buf)
455 struct efi_variable *var = &entry->var;
462 status = get_var_data(entry->efivars, var);
463 if (status != EFI_SUCCESS)
466 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
467 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
468 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
469 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
470 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
471 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
472 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
473 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
474 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
476 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
477 if (var->Attributes &
478 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
480 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
481 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
482 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
487 efivar_size_read(struct efivar_entry *entry, char *buf)
489 struct efi_variable *var = &entry->var;
496 status = get_var_data(entry->efivars, var);
497 if (status != EFI_SUCCESS)
500 str += sprintf(str, "0x%lx\n", var->DataSize);
505 efivar_data_read(struct efivar_entry *entry, char *buf)
507 struct efi_variable *var = &entry->var;
513 status = get_var_data(entry->efivars, var);
514 if (status != EFI_SUCCESS)
517 memcpy(buf, var->Data, var->DataSize);
518 return var->DataSize;
521 * We allow each variable to be edited via rewriting the
522 * entire efi variable structure.
525 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
527 struct efi_variable *new_var, *var = &entry->var;
528 struct efivars *efivars = entry->efivars;
529 efi_status_t status = EFI_NOT_FOUND;
531 if (count != sizeof(struct efi_variable))
534 new_var = (struct efi_variable *)buf;
536 * If only updating the variable data, then the name
537 * and guid should remain the same
539 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
540 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
541 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
545 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
546 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
550 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
551 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
552 printk(KERN_ERR "efivars: Malformed variable content\n");
556 spin_lock_irq(&efivars->lock);
558 status = check_var_size_locked(efivars, new_var->Attributes,
559 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
561 if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
562 status = efivars->ops->set_variable(new_var->VariableName,
563 &new_var->VendorGuid,
568 spin_unlock_irq(&efivars->lock);
570 if (status != EFI_SUCCESS) {
571 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
576 memcpy(&entry->var, new_var, count);
581 efivar_show_raw(struct efivar_entry *entry, char *buf)
583 struct efi_variable *var = &entry->var;
589 status = get_var_data(entry->efivars, var);
590 if (status != EFI_SUCCESS)
593 memcpy(buf, var, sizeof(*var));
598 * Generic read/write functions that call the specific functions of
601 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
604 struct efivar_entry *var = to_efivar_entry(kobj);
605 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
608 if (!capable(CAP_SYS_ADMIN))
611 if (efivar_attr->show) {
612 ret = efivar_attr->show(var, buf);
617 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
618 const char *buf, size_t count)
620 struct efivar_entry *var = to_efivar_entry(kobj);
621 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
624 if (!capable(CAP_SYS_ADMIN))
627 if (efivar_attr->store)
628 ret = efivar_attr->store(var, buf, count);
633 static const struct sysfs_ops efivar_attr_ops = {
634 .show = efivar_attr_show,
635 .store = efivar_attr_store,
638 static void efivar_release(struct kobject *kobj)
640 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
644 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
645 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
646 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
647 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
648 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
650 static struct attribute *def_attrs[] = {
651 &efivar_attr_guid.attr,
652 &efivar_attr_size.attr,
653 &efivar_attr_attributes.attr,
654 &efivar_attr_data.attr,
655 &efivar_attr_raw_var.attr,
659 static struct kobj_type efivar_ktype = {
660 .release = efivar_release,
661 .sysfs_ops = &efivar_attr_ops,
662 .default_attrs = def_attrs,
666 efivar_unregister(struct efivar_entry *var)
668 kobject_put(&var->kobj);
671 static int efi_status_to_err(efi_status_t status)
676 case EFI_INVALID_PARAMETER:
679 case EFI_OUT_OF_RESOURCES:
682 case EFI_DEVICE_ERROR:
685 case EFI_WRITE_PROTECTED:
688 case EFI_SECURITY_VIOLATION:
701 #ifdef CONFIG_EFI_VARS_PSTORE
703 static int efi_pstore_open(struct pstore_info *psi)
705 struct efivars *efivars = psi->data;
707 spin_lock_irq(&efivars->lock);
708 efivars->walk_entry = list_first_entry(&efivars->list,
709 struct efivar_entry, list);
713 static int efi_pstore_close(struct pstore_info *psi)
715 struct efivars *efivars = psi->data;
717 spin_unlock_irq(&efivars->lock);
721 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
722 struct timespec *timespec,
723 char **buf, struct pstore_info *psi)
725 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
726 struct efivars *efivars = psi->data;
727 char name[DUMP_NAME_LEN];
729 unsigned int part, size;
732 while (&efivars->walk_entry->list != &efivars->list) {
733 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
735 for (i = 0; i < DUMP_NAME_LEN; i++) {
736 name[i] = efivars->walk_entry->var.VariableName[i];
738 if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
740 timespec->tv_sec = time;
741 timespec->tv_nsec = 0;
742 get_var_data_locked(efivars, &efivars->walk_entry->var);
743 size = efivars->walk_entry->var.DataSize;
744 *buf = kmalloc(size, GFP_KERNEL);
747 memcpy(*buf, efivars->walk_entry->var.Data,
749 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
750 struct efivar_entry, list);
754 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
755 struct efivar_entry, list);
760 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
761 unsigned int part, size_t size, struct pstore_info *psi)
763 char name[DUMP_NAME_LEN];
764 char stub_name[DUMP_NAME_LEN];
765 efi_char16_t efi_name[DUMP_NAME_LEN];
766 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
767 struct efivars *efivars = psi->data;
768 struct efivar_entry *entry, *found = NULL;
770 efi_status_t status = EFI_NOT_FOUND;
773 sprintf(stub_name, "dump-type%u-%u-", type, part);
774 sprintf(name, "%s%lu", stub_name, get_seconds());
776 spin_lock_irqsave(&efivars->lock, flags);
780 * Check if there is a space enough to log.
781 * size: a size of logging data
782 * DUMP_NAME_LEN * 2: a maximum size of variable name
785 status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
786 size + DUMP_NAME_LEN * 2);
789 spin_unlock_irqrestore(&efivars->lock, flags);
795 for (i = 0; i < DUMP_NAME_LEN; i++)
796 efi_name[i] = stub_name[i];
799 * Clean up any entries with the same name
802 list_for_each_entry(entry, &efivars->list, list) {
803 get_var_data_locked(efivars, &entry->var);
805 if (efi_guidcmp(entry->var.VendorGuid, vendor))
807 if (utf16_strncmp(entry->var.VariableName, efi_name,
808 utf16_strlen(efi_name)))
810 /* Needs to be a prefix */
811 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
816 efivars->ops->set_variable(entry->var.VariableName,
817 &entry->var.VendorGuid,
818 PSTORE_EFI_ATTRIBUTES,
823 list_del(&found->list);
825 for (i = 0; i < DUMP_NAME_LEN; i++)
826 efi_name[i] = name[i];
828 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
831 spin_unlock_irqrestore(&efivars->lock, flags);
834 efivar_unregister(found);
836 if (efivar_wq_enabled)
837 schedule_work(&efivar_work);
843 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
844 struct pstore_info *psi)
846 efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
851 static struct pstore_info efi_pstore_info = {
852 .owner = THIS_MODULE,
854 .open = efi_pstore_open,
855 .close = efi_pstore_close,
856 .read = efi_pstore_read,
857 .write = efi_pstore_write,
858 .erase = efi_pstore_erase,
861 static void efivar_pstore_register(struct efivars *efivars)
863 efivars->efi_pstore_info = efi_pstore_info;
864 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
865 if (efivars->efi_pstore_info.buf) {
866 efivars->efi_pstore_info.bufsize = 1024;
867 efivars->efi_pstore_info.data = efivars;
868 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
869 pstore_register(&efivars->efi_pstore_info);
873 static void efivar_pstore_register(struct efivars *efivars)
879 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
880 struct bin_attribute *bin_attr,
881 char *buf, loff_t pos, size_t count)
883 struct efi_variable *new_var = (struct efi_variable *)buf;
884 struct efivars *efivars = bin_attr->private;
885 struct efivar_entry *search_efivar, *n;
886 unsigned long strsize1, strsize2;
887 efi_status_t status = EFI_NOT_FOUND;
890 if (!capable(CAP_SYS_ADMIN))
893 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
894 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
895 printk(KERN_ERR "efivars: Malformed variable content\n");
899 spin_lock_irq(&efivars->lock);
902 * Does this variable already exist?
904 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
905 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
906 strsize2 = utf16_strsize(new_var->VariableName, 1024);
907 if (strsize1 == strsize2 &&
908 !memcmp(&(search_efivar->var.VariableName),
909 new_var->VariableName, strsize1) &&
910 !efi_guidcmp(search_efivar->var.VendorGuid,
911 new_var->VendorGuid)) {
917 spin_unlock_irq(&efivars->lock);
921 status = check_var_size_locked(efivars, new_var->Attributes,
922 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
924 if (status && status != EFI_UNSUPPORTED) {
925 spin_unlock_irq(&efivars->lock);
926 return efi_status_to_err(status);
929 /* now *really* create the variable via EFI */
930 status = efivars->ops->set_variable(new_var->VariableName,
931 &new_var->VendorGuid,
936 if (status != EFI_SUCCESS) {
937 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
939 spin_unlock_irq(&efivars->lock);
942 spin_unlock_irq(&efivars->lock);
944 /* Create the entry in sysfs. Locking is not required here */
945 status = efivar_create_sysfs_entry(efivars,
946 utf16_strsize(new_var->VariableName,
948 new_var->VariableName,
949 &new_var->VendorGuid);
951 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
956 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
957 struct bin_attribute *bin_attr,
958 char *buf, loff_t pos, size_t count)
960 struct efi_variable *del_var = (struct efi_variable *)buf;
961 struct efivars *efivars = bin_attr->private;
962 struct efivar_entry *search_efivar, *n;
963 unsigned long strsize1, strsize2;
964 efi_status_t status = EFI_NOT_FOUND;
967 if (!capable(CAP_SYS_ADMIN))
970 spin_lock_irq(&efivars->lock);
973 * Does this variable already exist?
975 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
976 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
977 strsize2 = utf16_strsize(del_var->VariableName, 1024);
978 if (strsize1 == strsize2 &&
979 !memcmp(&(search_efivar->var.VariableName),
980 del_var->VariableName, strsize1) &&
981 !efi_guidcmp(search_efivar->var.VendorGuid,
982 del_var->VendorGuid)) {
988 spin_unlock_irq(&efivars->lock);
991 /* force the Attributes/DataSize to 0 to ensure deletion */
992 del_var->Attributes = 0;
993 del_var->DataSize = 0;
995 status = efivars->ops->set_variable(del_var->VariableName,
996 &del_var->VendorGuid,
1001 if (status != EFI_SUCCESS) {
1002 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1004 spin_unlock_irq(&efivars->lock);
1007 list_del(&search_efivar->list);
1008 /* We need to release this lock before unregistering. */
1009 spin_unlock_irq(&efivars->lock);
1010 efivar_unregister(search_efivar);
1012 /* It's dead Jim.... */
1016 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1018 struct efivar_entry *entry, *n;
1019 struct efivars *efivars = &__efivars;
1020 unsigned long strsize1, strsize2;
1023 strsize1 = utf16_strsize(variable_name, 1024);
1024 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1025 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1026 if (strsize1 == strsize2 &&
1027 !memcmp(variable_name, &(entry->var.VariableName),
1029 !efi_guidcmp(entry->var.VendorGuid,
1039 * Returns the size of variable_name, in bytes, including the
1040 * terminating NULL character, or variable_name_size if no NULL
1041 * character is found among the first variable_name_size bytes.
1043 static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1044 unsigned long variable_name_size)
1050 * The variable name is, by definition, a NULL-terminated
1051 * string, so make absolutely sure that variable_name_size is
1052 * the value we expect it to be. If not, return the real size.
1054 for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1055 c = variable_name[(len / sizeof(c)) - 1];
1060 return min(len, variable_name_size);
1063 static void efivar_update_sysfs_entries(struct work_struct *work)
1065 struct efivars *efivars = &__efivars;
1067 efi_char16_t *variable_name;
1068 unsigned long variable_name_size = 1024;
1069 efi_status_t status = EFI_NOT_FOUND;
1072 /* Add new sysfs entries */
1074 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1075 if (!variable_name) {
1076 pr_err("efivars: Memory allocation failed.\n");
1080 spin_lock_irq(&efivars->lock);
1083 variable_name_size = 1024;
1084 status = efivars->ops->get_next_variable(
1085 &variable_name_size,
1088 if (status != EFI_SUCCESS) {
1091 if (!variable_is_present(variable_name,
1098 spin_unlock_irq(&efivars->lock);
1101 kfree(variable_name);
1104 variable_name_size = var_name_strnsize(variable_name,
1105 variable_name_size);
1106 efivar_create_sysfs_entry(efivars,
1108 variable_name, &vendor);
1114 * Let's not leave out systab information that snuck into
1115 * the efivars driver
1117 static ssize_t systab_show(struct kobject *kobj,
1118 struct kobj_attribute *attr, char *buf)
1125 if (efi.mps != EFI_INVALID_TABLE_ADDR)
1126 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1127 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1128 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1129 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1130 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1131 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1132 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1133 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1134 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1135 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1136 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1137 if (efi.uga != EFI_INVALID_TABLE_ADDR)
1138 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1143 static struct kobj_attribute efi_attr_systab =
1144 __ATTR(systab, 0400, systab_show, NULL);
1146 static struct attribute *efi_subsys_attrs[] = {
1147 &efi_attr_systab.attr,
1148 NULL, /* maybe more in the future? */
1151 static struct attribute_group efi_subsys_attr_group = {
1152 .attrs = efi_subsys_attrs,
1155 static struct kobject *efi_kobj;
1158 * efivar_create_sysfs_entry()
1160 * variable_name_size = number of bytes required to hold
1161 * variable_name (not counting the NULL
1162 * character at the end.
1163 * efivars->lock is not held on entry or exit.
1164 * Returns 1 on failure, 0 on success
1167 efivar_create_sysfs_entry(struct efivars *efivars,
1168 unsigned long variable_name_size,
1169 efi_char16_t *variable_name,
1170 efi_guid_t *vendor_guid)
1172 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1174 struct efivar_entry *new_efivar;
1176 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1177 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1179 if (!short_name || !new_efivar) {
1185 new_efivar->efivars = efivars;
1186 memcpy(new_efivar->var.VariableName, variable_name,
1187 variable_name_size);
1188 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1190 /* Convert Unicode to normal chars (assume top bits are 0),
1192 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1193 short_name[i] = variable_name[i] & 0xFF;
1195 /* This is ugly, but necessary to separate one vendor's
1196 private variables from another's. */
1198 *(short_name + strlen(short_name)) = '-';
1199 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1201 new_efivar->kobj.kset = efivars->kset;
1202 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1210 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1214 spin_lock_irq(&efivars->lock);
1215 list_add(&new_efivar->list, &efivars->list);
1216 spin_unlock_irq(&efivars->lock);
1222 create_efivars_bin_attributes(struct efivars *efivars)
1224 struct bin_attribute *attr;
1228 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1232 attr->attr.name = "new_var";
1233 attr->attr.mode = 0200;
1234 attr->write = efivar_create;
1235 attr->private = efivars;
1236 efivars->new_var = attr;
1239 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1244 attr->attr.name = "del_var";
1245 attr->attr.mode = 0200;
1246 attr->write = efivar_delete;
1247 attr->private = efivars;
1248 efivars->del_var = attr;
1250 sysfs_bin_attr_init(efivars->new_var);
1251 sysfs_bin_attr_init(efivars->del_var);
1254 error = sysfs_create_bin_file(&efivars->kset->kobj,
1257 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1258 " due to error %d\n", error);
1261 error = sysfs_create_bin_file(&efivars->kset->kobj,
1264 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1265 " due to error %d\n", error);
1266 sysfs_remove_bin_file(&efivars->kset->kobj,
1273 kfree(efivars->del_var);
1274 efivars->del_var = NULL;
1275 kfree(efivars->new_var);
1276 efivars->new_var = NULL;
1280 void unregister_efivars(struct efivars *efivars)
1282 struct efivar_entry *entry, *n;
1284 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1285 spin_lock_irq(&efivars->lock);
1286 list_del(&entry->list);
1287 spin_unlock_irq(&efivars->lock);
1288 efivar_unregister(entry);
1290 if (efivars->new_var)
1291 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1292 if (efivars->del_var)
1293 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1294 kfree(efivars->new_var);
1295 kfree(efivars->del_var);
1296 kset_unregister(efivars->kset);
1298 EXPORT_SYMBOL_GPL(unregister_efivars);
1301 * Print a warning when duplicate EFI variables are encountered and
1302 * disable the sysfs workqueue since the firmware is buggy.
1304 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1305 unsigned long len16)
1307 size_t i, len8 = len16 / sizeof(efi_char16_t);
1311 * Disable the workqueue since the algorithm it uses for
1312 * detecting new variables won't work with this buggy
1313 * implementation of GetNextVariableName().
1315 efivar_wq_enabled = false;
1317 s8 = kzalloc(len8, GFP_KERNEL);
1321 for (i = 0; i < len8; i++)
1324 printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
1329 int register_efivars(struct efivars *efivars,
1330 const struct efivar_operations *ops,
1331 struct kobject *parent_kobj)
1333 efi_status_t status = EFI_NOT_FOUND;
1334 efi_guid_t vendor_guid;
1335 efi_char16_t *variable_name;
1336 unsigned long variable_name_size = 1024;
1339 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1340 if (!variable_name) {
1341 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1345 spin_lock_init(&efivars->lock);
1346 INIT_LIST_HEAD(&efivars->list);
1349 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1350 if (!efivars->kset) {
1351 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1357 * Per EFI spec, the maximum storage allocated for both
1358 * the variable name and variable data is 1024 bytes.
1362 variable_name_size = 1024;
1364 status = ops->get_next_variable(&variable_name_size,
1369 variable_name_size = var_name_strnsize(variable_name,
1370 variable_name_size);
1373 * Some firmware implementations return the
1374 * same variable name on multiple calls to
1375 * get_next_variable(). Terminate the loop
1376 * immediately as there is no guarantee that
1377 * we'll ever see a different variable name,
1378 * and may end up looping here forever.
1380 if (variable_is_present(variable_name, &vendor_guid)) {
1381 dup_variable_bug(variable_name, &vendor_guid,
1382 variable_name_size);
1383 status = EFI_NOT_FOUND;
1387 efivar_create_sysfs_entry(efivars,
1395 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1397 status = EFI_NOT_FOUND;
1400 } while (status != EFI_NOT_FOUND);
1402 error = create_efivars_bin_attributes(efivars);
1404 unregister_efivars(efivars);
1406 if (!efivars_pstore_disable)
1407 efivar_pstore_register(efivars);
1410 kfree(variable_name);
1414 EXPORT_SYMBOL_GPL(register_efivars);
1416 static struct efivar_operations ops;
1419 * For now we register the efi subsystem with the firmware subsystem
1420 * and the vars subsystem with the efi subsystem. In the future, it
1421 * might make sense to split off the efi subsystem into its own
1422 * driver, but for now only efivars will register with it, so just
1431 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1434 if (!efi_enabled(EFI_RUNTIME_SERVICES))
1437 /* For now we'll register the efi directory at /sys/firmware/efi */
1438 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1440 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1444 ops.get_variable = efi.get_variable;
1445 ops.set_variable = efi.set_variable;
1446 ops.get_next_variable = efi.get_next_variable;
1447 ops.query_variable_store = efi_query_variable_store;
1448 error = register_efivars(&__efivars, &ops, efi_kobj);
1452 /* Don't forget the systab entry */
1453 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1456 "efivars: Sysfs attribute export failed with error %d.\n",
1458 goto err_unregister;
1464 unregister_efivars(&__efivars);
1466 kobject_put(efi_kobj);
1473 cancel_work_sync(&efivar_work);
1475 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1476 unregister_efivars(&__efivars);
1477 kobject_put(efi_kobj);
1481 module_init(efivars_init);
1482 module_exit(efivars_exit);