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(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 #define PSTORE_EFI_ATTRIBUTES \
131 (EFI_VARIABLE_NON_VOLATILE | \
132 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
133 EFI_VARIABLE_RUNTIME_ACCESS)
135 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
136 struct efivar_attribute efivar_attr_##_name = { \
137 .attr = {.name = __stringify(_name), .mode = _mode}, \
142 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
143 #define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
146 * Prototype for sysfs creation function
149 efivar_create_sysfs_entry(struct efivars *efivars,
150 unsigned long variable_name_size,
151 efi_char16_t *variable_name,
152 efi_guid_t *vendor_guid);
154 /* Return the number of unicode characters in data */
156 utf16_strnlen(efi_char16_t *s, size_t maxlength)
158 unsigned long length = 0;
160 while (*s++ != 0 && length < maxlength)
165 static inline unsigned long
166 utf16_strlen(efi_char16_t *s)
168 return utf16_strnlen(s, ~0UL);
172 * Return the number of bytes is the length of this string
173 * Note: this is NOT the same as the number of unicode characters
175 static inline unsigned long
176 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
178 return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
182 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
191 if (*a == 0) /* implies *b == 0 */
200 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
203 struct efi_generic_dev_path *node;
206 node = (struct efi_generic_dev_path *)buffer;
208 if (len < sizeof(*node))
211 while (offset <= len - sizeof(*node) &&
212 node->length >= sizeof(*node) &&
213 node->length <= len - offset) {
214 offset += node->length;
216 if ((node->type == EFI_DEV_END_PATH ||
217 node->type == EFI_DEV_END_PATH2) &&
218 node->sub_type == EFI_DEV_END_ENTIRE)
221 node = (struct efi_generic_dev_path *)(buffer + offset);
225 * If we're here then either node->length pointed past the end
226 * of the buffer or we reached the end of the buffer without
227 * finding a device path end node.
233 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
236 /* An array of 16-bit integers */
244 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
248 int i, desclength = 0, namelen;
250 namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
252 /* Either "Boot" or "Driver" followed by four digits of hex */
253 for (i = match; i < match+4; i++) {
254 if (var->VariableName[i] > 127 ||
255 hex_to_bin(var->VariableName[i] & 0xff) < 0)
259 /* Reject it if there's 4 digits of hex and then further content */
260 if (namelen > match + 4)
263 /* A valid entry must be at least 8 bytes */
267 filepathlength = buffer[4] | buffer[5] << 8;
270 * There's no stored length for the description, so it has to be
273 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
275 /* Each boot entry must have a descriptor */
280 * If the sum of the length of the description, the claimed filepath
281 * length and the original header are greater than the length of the
282 * variable, it's malformed
284 if ((desclength + filepathlength + 6) > len)
288 * And, finally, check the filepath
290 return validate_device_path(var, match, buffer + desclength + 6,
295 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
298 /* A single 16-bit integer */
306 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
311 for (i = 0; i < len; i++) {
322 struct variable_validate {
324 bool (*validate)(struct efi_variable *var, int match, u8 *data,
328 static const struct variable_validate variable_validate[] = {
329 { "BootNext", validate_uint16 },
330 { "BootOrder", validate_boot_order },
331 { "DriverOrder", validate_boot_order },
332 { "Boot*", validate_load_option },
333 { "Driver*", validate_load_option },
334 { "ConIn", validate_device_path },
335 { "ConInDev", validate_device_path },
336 { "ConOut", validate_device_path },
337 { "ConOutDev", validate_device_path },
338 { "ErrOut", validate_device_path },
339 { "ErrOutDev", validate_device_path },
340 { "Timeout", validate_uint16 },
341 { "Lang", validate_ascii_string },
342 { "PlatformLang", validate_ascii_string },
347 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
350 u16 *unicode_name = var->VariableName;
352 for (i = 0; variable_validate[i].validate != NULL; i++) {
353 const char *name = variable_validate[i].name;
356 for (match = 0; ; match++) {
357 char c = name[match];
358 u16 u = unicode_name[match];
360 /* All special variables are plain ascii */
364 /* Wildcard in the matching name means we've matched */
366 return variable_validate[i].validate(var,
369 /* Case sensitive match */
373 /* Reached the end of the string while matching */
375 return variable_validate[i].validate(var,
384 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
388 var->DataSize = 1024;
389 status = efivars->ops->get_variable(var->VariableName,
398 get_var_data(struct efivars *efivars, struct efi_variable *var)
403 spin_lock_irqsave(&efivars->lock, flags);
404 status = get_var_data_locked(efivars, var);
405 spin_unlock_irqrestore(&efivars->lock, flags);
407 if (status != EFI_SUCCESS) {
408 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
415 check_var_size_locked(struct efivars *efivars, u32 attributes,
418 u64 storage_size, remaining_size, max_size;
420 const struct efivar_operations *fops = efivars->ops;
422 if (!efivars->ops->query_variable_info)
423 return EFI_UNSUPPORTED;
425 status = fops->query_variable_info(attributes, &storage_size,
426 &remaining_size, &max_size);
428 if (status != EFI_SUCCESS)
431 if (!storage_size || size > remaining_size || size > max_size ||
432 (remaining_size - size) < (storage_size / 2))
433 return EFI_OUT_OF_RESOURCES;
439 efivar_guid_read(struct efivar_entry *entry, char *buf)
441 struct efi_variable *var = &entry->var;
447 efi_guid_unparse(&var->VendorGuid, str);
449 str += sprintf(str, "\n");
455 efivar_attr_read(struct efivar_entry *entry, char *buf)
457 struct efi_variable *var = &entry->var;
464 status = get_var_data(entry->efivars, var);
465 if (status != EFI_SUCCESS)
468 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
469 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
470 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
471 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
472 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
473 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
474 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
475 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
476 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
478 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
479 if (var->Attributes &
480 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
482 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
483 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
484 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
489 efivar_size_read(struct efivar_entry *entry, char *buf)
491 struct efi_variable *var = &entry->var;
498 status = get_var_data(entry->efivars, var);
499 if (status != EFI_SUCCESS)
502 str += sprintf(str, "0x%lx\n", var->DataSize);
507 efivar_data_read(struct efivar_entry *entry, char *buf)
509 struct efi_variable *var = &entry->var;
515 status = get_var_data(entry->efivars, var);
516 if (status != EFI_SUCCESS)
519 memcpy(buf, var->Data, var->DataSize);
520 return var->DataSize;
523 * We allow each variable to be edited via rewriting the
524 * entire efi variable structure.
527 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
529 struct efi_variable *new_var, *var = &entry->var;
530 struct efivars *efivars = entry->efivars;
531 efi_status_t status = EFI_NOT_FOUND;
533 if (count != sizeof(struct efi_variable))
536 new_var = (struct efi_variable *)buf;
538 * If only updating the variable data, then the name
539 * and guid should remain the same
541 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
542 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
543 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
547 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
548 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
552 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
553 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
554 printk(KERN_ERR "efivars: Malformed variable content\n");
558 spin_lock_irq(&efivars->lock);
560 status = check_var_size_locked(efivars, new_var->Attributes,
561 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
563 if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
564 status = efivars->ops->set_variable(new_var->VariableName,
565 &new_var->VendorGuid,
570 spin_unlock_irq(&efivars->lock);
572 if (status != EFI_SUCCESS) {
573 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
578 memcpy(&entry->var, new_var, count);
583 efivar_show_raw(struct efivar_entry *entry, char *buf)
585 struct efi_variable *var = &entry->var;
591 status = get_var_data(entry->efivars, var);
592 if (status != EFI_SUCCESS)
595 memcpy(buf, var, sizeof(*var));
600 * Generic read/write functions that call the specific functions of
603 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
606 struct efivar_entry *var = to_efivar_entry(kobj);
607 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
610 if (!capable(CAP_SYS_ADMIN))
613 if (efivar_attr->show) {
614 ret = efivar_attr->show(var, buf);
619 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
620 const char *buf, size_t count)
622 struct efivar_entry *var = to_efivar_entry(kobj);
623 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
626 if (!capable(CAP_SYS_ADMIN))
629 if (efivar_attr->store)
630 ret = efivar_attr->store(var, buf, count);
635 static const struct sysfs_ops efivar_attr_ops = {
636 .show = efivar_attr_show,
637 .store = efivar_attr_store,
640 static void efivar_release(struct kobject *kobj)
642 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
646 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
647 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
648 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
649 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
650 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
652 static struct attribute *def_attrs[] = {
653 &efivar_attr_guid.attr,
654 &efivar_attr_size.attr,
655 &efivar_attr_attributes.attr,
656 &efivar_attr_data.attr,
657 &efivar_attr_raw_var.attr,
661 static struct kobj_type efivar_ktype = {
662 .release = efivar_release,
663 .sysfs_ops = &efivar_attr_ops,
664 .default_attrs = def_attrs,
668 efivar_unregister(struct efivar_entry *var)
670 kobject_put(&var->kobj);
673 static int efi_status_to_err(efi_status_t status)
678 case EFI_INVALID_PARAMETER:
681 case EFI_OUT_OF_RESOURCES:
684 case EFI_DEVICE_ERROR:
687 case EFI_WRITE_PROTECTED:
690 case EFI_SECURITY_VIOLATION:
703 #ifdef CONFIG_EFI_VARS_PSTORE
705 static int efi_pstore_open(struct pstore_info *psi)
707 struct efivars *efivars = psi->data;
709 spin_lock_irq(&efivars->lock);
710 efivars->walk_entry = list_first_entry(&efivars->list,
711 struct efivar_entry, list);
715 static int efi_pstore_close(struct pstore_info *psi)
717 struct efivars *efivars = psi->data;
719 spin_unlock_irq(&efivars->lock);
723 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
724 struct timespec *timespec,
725 char **buf, struct pstore_info *psi)
727 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
728 struct efivars *efivars = psi->data;
729 char name[DUMP_NAME_LEN];
731 unsigned int part, size;
734 while (&efivars->walk_entry->list != &efivars->list) {
735 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
737 for (i = 0; i < DUMP_NAME_LEN; i++) {
738 name[i] = efivars->walk_entry->var.VariableName[i];
740 if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
742 timespec->tv_sec = time;
743 timespec->tv_nsec = 0;
744 get_var_data_locked(efivars, &efivars->walk_entry->var);
745 size = efivars->walk_entry->var.DataSize;
746 *buf = kmalloc(size, GFP_KERNEL);
749 memcpy(*buf, efivars->walk_entry->var.Data,
751 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
752 struct efivar_entry, list);
756 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
757 struct efivar_entry, list);
762 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
763 unsigned int part, size_t size, struct pstore_info *psi)
765 char name[DUMP_NAME_LEN];
766 char stub_name[DUMP_NAME_LEN];
767 efi_char16_t efi_name[DUMP_NAME_LEN];
768 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
769 struct efivars *efivars = psi->data;
770 struct efivar_entry *entry, *found = NULL;
772 efi_status_t status = EFI_NOT_FOUND;
775 sprintf(stub_name, "dump-type%u-%u-", type, part);
776 sprintf(name, "%s%lu", stub_name, get_seconds());
778 spin_lock_irqsave(&efivars->lock, flags);
781 * Check if there is a space enough to log.
782 * size: a size of logging data
783 * DUMP_NAME_LEN * 2: a maximum size of variable name
786 status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
787 size + DUMP_NAME_LEN * 2);
790 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);
837 ret = efivar_create_sysfs_entry(efivars,
838 utf16_strsize(efi_name,
846 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
847 struct pstore_info *psi)
849 efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
854 static struct pstore_info efi_pstore_info = {
855 .owner = THIS_MODULE,
857 .open = efi_pstore_open,
858 .close = efi_pstore_close,
859 .read = efi_pstore_read,
860 .write = efi_pstore_write,
861 .erase = efi_pstore_erase,
864 static void efivar_pstore_register(struct efivars *efivars)
866 efivars->efi_pstore_info = efi_pstore_info;
867 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
868 if (efivars->efi_pstore_info.buf) {
869 efivars->efi_pstore_info.bufsize = 1024;
870 efivars->efi_pstore_info.data = efivars;
871 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
872 pstore_register(&efivars->efi_pstore_info);
876 static void efivar_pstore_register(struct efivars *efivars)
882 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
883 struct bin_attribute *bin_attr,
884 char *buf, loff_t pos, size_t count)
886 struct efi_variable *new_var = (struct efi_variable *)buf;
887 struct efivars *efivars = bin_attr->private;
888 struct efivar_entry *search_efivar, *n;
889 unsigned long strsize1, strsize2;
890 efi_status_t status = EFI_NOT_FOUND;
893 if (!capable(CAP_SYS_ADMIN))
896 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
897 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
898 printk(KERN_ERR "efivars: Malformed variable content\n");
902 spin_lock_irq(&efivars->lock);
905 * Does this variable already exist?
907 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
908 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
909 strsize2 = utf16_strsize(new_var->VariableName, 1024);
910 if (strsize1 == strsize2 &&
911 !memcmp(&(search_efivar->var.VariableName),
912 new_var->VariableName, strsize1) &&
913 !efi_guidcmp(search_efivar->var.VendorGuid,
914 new_var->VendorGuid)) {
920 spin_unlock_irq(&efivars->lock);
924 status = check_var_size_locked(efivars, new_var->Attributes,
925 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
927 if (status && status != EFI_UNSUPPORTED) {
928 spin_unlock_irq(&efivars->lock);
929 return efi_status_to_err(status);
932 /* now *really* create the variable via EFI */
933 status = efivars->ops->set_variable(new_var->VariableName,
934 &new_var->VendorGuid,
939 if (status != EFI_SUCCESS) {
940 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
942 spin_unlock_irq(&efivars->lock);
945 spin_unlock_irq(&efivars->lock);
947 /* Create the entry in sysfs. Locking is not required here */
948 status = efivar_create_sysfs_entry(efivars,
949 utf16_strsize(new_var->VariableName,
951 new_var->VariableName,
952 &new_var->VendorGuid);
954 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
959 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
960 struct bin_attribute *bin_attr,
961 char *buf, loff_t pos, size_t count)
963 struct efi_variable *del_var = (struct efi_variable *)buf;
964 struct efivars *efivars = bin_attr->private;
965 struct efivar_entry *search_efivar, *n;
966 unsigned long strsize1, strsize2;
967 efi_status_t status = EFI_NOT_FOUND;
970 if (!capable(CAP_SYS_ADMIN))
973 spin_lock_irq(&efivars->lock);
976 * Does this variable already exist?
978 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
979 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
980 strsize2 = utf16_strsize(del_var->VariableName, 1024);
981 if (strsize1 == strsize2 &&
982 !memcmp(&(search_efivar->var.VariableName),
983 del_var->VariableName, strsize1) &&
984 !efi_guidcmp(search_efivar->var.VendorGuid,
985 del_var->VendorGuid)) {
991 spin_unlock_irq(&efivars->lock);
994 /* force the Attributes/DataSize to 0 to ensure deletion */
995 del_var->Attributes = 0;
996 del_var->DataSize = 0;
998 status = efivars->ops->set_variable(del_var->VariableName,
999 &del_var->VendorGuid,
1000 del_var->Attributes,
1004 if (status != EFI_SUCCESS) {
1005 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1007 spin_unlock_irq(&efivars->lock);
1010 list_del(&search_efivar->list);
1011 /* We need to release this lock before unregistering. */
1012 spin_unlock_irq(&efivars->lock);
1013 efivar_unregister(search_efivar);
1015 /* It's dead Jim.... */
1020 * Let's not leave out systab information that snuck into
1021 * the efivars driver
1023 static ssize_t systab_show(struct kobject *kobj,
1024 struct kobj_attribute *attr, char *buf)
1031 if (efi.mps != EFI_INVALID_TABLE_ADDR)
1032 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1033 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1034 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1035 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1036 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1037 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1038 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1039 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1040 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1041 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1042 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1043 if (efi.uga != EFI_INVALID_TABLE_ADDR)
1044 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1049 static struct kobj_attribute efi_attr_systab =
1050 __ATTR(systab, 0400, systab_show, NULL);
1052 static struct attribute *efi_subsys_attrs[] = {
1053 &efi_attr_systab.attr,
1054 NULL, /* maybe more in the future? */
1057 static struct attribute_group efi_subsys_attr_group = {
1058 .attrs = efi_subsys_attrs,
1061 static struct kobject *efi_kobj;
1064 * efivar_create_sysfs_entry()
1066 * variable_name_size = number of bytes required to hold
1067 * variable_name (not counting the NULL
1068 * character at the end.
1069 * efivars->lock is not held on entry or exit.
1070 * Returns 1 on failure, 0 on success
1073 efivar_create_sysfs_entry(struct efivars *efivars,
1074 unsigned long variable_name_size,
1075 efi_char16_t *variable_name,
1076 efi_guid_t *vendor_guid)
1078 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1080 struct efivar_entry *new_efivar;
1082 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1083 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1085 if (!short_name || !new_efivar) {
1091 new_efivar->efivars = efivars;
1092 memcpy(new_efivar->var.VariableName, variable_name,
1093 variable_name_size);
1094 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1096 /* Convert Unicode to normal chars (assume top bits are 0),
1098 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1099 short_name[i] = variable_name[i] & 0xFF;
1101 /* This is ugly, but necessary to separate one vendor's
1102 private variables from another's. */
1104 *(short_name + strlen(short_name)) = '-';
1105 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1107 new_efivar->kobj.kset = efivars->kset;
1108 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1116 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1120 spin_lock_irq(&efivars->lock);
1121 list_add(&new_efivar->list, &efivars->list);
1122 spin_unlock_irq(&efivars->lock);
1128 create_efivars_bin_attributes(struct efivars *efivars)
1130 struct bin_attribute *attr;
1134 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1138 attr->attr.name = "new_var";
1139 attr->attr.mode = 0200;
1140 attr->write = efivar_create;
1141 attr->private = efivars;
1142 efivars->new_var = attr;
1145 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1150 attr->attr.name = "del_var";
1151 attr->attr.mode = 0200;
1152 attr->write = efivar_delete;
1153 attr->private = efivars;
1154 efivars->del_var = attr;
1156 sysfs_bin_attr_init(efivars->new_var);
1157 sysfs_bin_attr_init(efivars->del_var);
1160 error = sysfs_create_bin_file(&efivars->kset->kobj,
1163 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1164 " due to error %d\n", error);
1167 error = sysfs_create_bin_file(&efivars->kset->kobj,
1170 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1171 " due to error %d\n", error);
1172 sysfs_remove_bin_file(&efivars->kset->kobj,
1179 kfree(efivars->del_var);
1180 efivars->del_var = NULL;
1181 kfree(efivars->new_var);
1182 efivars->new_var = NULL;
1186 void unregister_efivars(struct efivars *efivars)
1188 struct efivar_entry *entry, *n;
1190 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1191 spin_lock_irq(&efivars->lock);
1192 list_del(&entry->list);
1193 spin_unlock_irq(&efivars->lock);
1194 efivar_unregister(entry);
1196 if (efivars->new_var)
1197 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1198 if (efivars->del_var)
1199 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1200 kfree(efivars->new_var);
1201 kfree(efivars->del_var);
1202 kset_unregister(efivars->kset);
1204 EXPORT_SYMBOL_GPL(unregister_efivars);
1206 int register_efivars(struct efivars *efivars,
1207 const struct efivar_operations *ops,
1208 struct kobject *parent_kobj)
1210 efi_status_t status = EFI_NOT_FOUND;
1211 efi_guid_t vendor_guid;
1212 efi_char16_t *variable_name;
1213 unsigned long variable_name_size = 1024;
1216 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1217 if (!variable_name) {
1218 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1222 spin_lock_init(&efivars->lock);
1223 INIT_LIST_HEAD(&efivars->list);
1226 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1227 if (!efivars->kset) {
1228 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1234 * Per EFI spec, the maximum storage allocated for both
1235 * the variable name and variable data is 1024 bytes.
1239 variable_name_size = 1024;
1241 status = ops->get_next_variable(&variable_name_size,
1246 efivar_create_sysfs_entry(efivars,
1254 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1256 status = EFI_NOT_FOUND;
1259 } while (status != EFI_NOT_FOUND);
1261 error = create_efivars_bin_attributes(efivars);
1263 unregister_efivars(efivars);
1265 if (!efivars_pstore_disable)
1266 efivar_pstore_register(efivars);
1269 kfree(variable_name);
1273 EXPORT_SYMBOL_GPL(register_efivars);
1275 static struct efivars __efivars;
1276 static struct efivar_operations ops;
1279 * For now we register the efi subsystem with the firmware subsystem
1280 * and the vars subsystem with the efi subsystem. In the future, it
1281 * might make sense to split off the efi subsystem into its own
1282 * driver, but for now only efivars will register with it, so just
1291 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1294 if (!efi_enabled(EFI_RUNTIME_SERVICES))
1297 /* For now we'll register the efi directory at /sys/firmware/efi */
1298 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1300 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1304 ops.get_variable = efi.get_variable;
1305 ops.set_variable = efi.set_variable;
1306 ops.get_next_variable = efi.get_next_variable;
1307 ops.query_variable_info = efi.query_variable_info;
1308 error = register_efivars(&__efivars, &ops, efi_kobj);
1312 /* Don't forget the systab entry */
1313 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1316 "efivars: Sysfs attribute export failed with error %d.\n",
1318 goto err_unregister;
1324 unregister_efivars(&__efivars);
1326 kobject_put(efi_kobj);
1333 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1334 unregister_efivars(&__efivars);
1335 kobject_put(efi_kobj);
1339 module_init(efivars_init);
1340 module_exit(efivars_exit);