2 * EFI Variables - efivars.c
4 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
7 * This code takes all variables accessible from EFI runtime and
8 * exports them via sysfs
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 * 17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27 * remove check for efi_enabled in exit
30 * 26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
33 * 21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34 * converted driver to export variable information via sysfs
35 * and moved to drivers/firmware directory
36 * bumped revision number to v0.07 to reflect conversion & move
38 * 10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39 * fix locking per Peter Chubb's findings
41 * 25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42 * move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
44 * 12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45 * use list_for_each_safe when deleting vars.
46 * remove ifdef CONFIG_SMP around include <linux/smp.h>
47 * v0.04 release to linux-ia64@linuxia64.org
49 * 20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50 * Moved vars from /proc/efi to /proc/efi/vars, and made
51 * efi.c own the /proc/efi directory.
52 * v0.03 release to linux-ia64@linuxia64.org
54 * 26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55 * At the request of Stephane, moved ownership of /proc/efi
56 * to efi.c, and now efivars lives under /proc/efi/vars.
58 * 12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59 * Feedback received from Stephane Eranian incorporated.
60 * efivar_write() checks copy_from_user() return value.
61 * efivar_read/write() returns proper errno.
62 * v0.02 release to linux-ia64@linuxia64.org
64 * 26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65 * v0.01 release to linux-ia64@linuxia64.org
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81 #include <linux/pstore.h>
83 #include <asm/uaccess.h>
85 #define EFIVARS_VERSION "0.08"
86 #define EFIVARS_DATE "2004-May-17"
88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
90 MODULE_LICENSE("GPL");
91 MODULE_VERSION(EFIVARS_VERSION);
93 #define DUMP_NAME_LEN 52
96 * The maximum size of VariableName + Data = 1024
97 * Therefore, it's reasonable to save that much
98 * space in each part of the structure,
99 * and we use a page for reading/writing.
102 struct efi_variable {
103 efi_char16_t VariableName[1024/sizeof(efi_char16_t)];
104 efi_guid_t VendorGuid;
105 unsigned long DataSize;
109 } __attribute__((packed));
112 struct efivar_entry {
113 struct efivars *efivars;
114 struct efi_variable var;
115 struct list_head list;
119 struct efivar_attribute {
120 struct attribute attr;
121 ssize_t (*show) (struct efivar_entry *entry, char *buf);
122 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
125 #define PSTORE_EFI_ATTRIBUTES \
126 (EFI_VARIABLE_NON_VOLATILE | \
127 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
128 EFI_VARIABLE_RUNTIME_ACCESS)
130 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
131 struct efivar_attribute efivar_attr_##_name = { \
132 .attr = {.name = __stringify(_name), .mode = _mode}, \
137 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
138 #define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
141 * Prototype for sysfs creation function
144 efivar_create_sysfs_entry(struct efivars *efivars,
145 unsigned long variable_name_size,
146 efi_char16_t *variable_name,
147 efi_guid_t *vendor_guid);
149 /* Return the number of unicode characters in data */
151 utf16_strnlen(efi_char16_t *s, size_t maxlength)
153 unsigned long length = 0;
155 while (*s++ != 0 && length < maxlength)
160 static inline unsigned long
161 utf16_strlen(efi_char16_t *s)
163 return utf16_strnlen(s, ~0UL);
167 * Return the number of bytes is the length of this string
168 * Note: this is NOT the same as the number of unicode characters
170 static inline unsigned long
171 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
173 return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
177 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
186 if (*a == 0) /* implies *b == 0 */
195 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
198 struct efi_generic_dev_path *node;
201 node = (struct efi_generic_dev_path *)buffer;
203 if (len < sizeof(*node))
206 while (offset <= len - sizeof(*node) &&
207 node->length >= sizeof(*node) &&
208 node->length <= len - offset) {
209 offset += node->length;
211 if ((node->type == EFI_DEV_END_PATH ||
212 node->type == EFI_DEV_END_PATH2) &&
213 node->sub_type == EFI_DEV_END_ENTIRE)
216 node = (struct efi_generic_dev_path *)(buffer + offset);
220 * If we're here then either node->length pointed past the end
221 * of the buffer or we reached the end of the buffer without
222 * finding a device path end node.
228 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
231 /* An array of 16-bit integers */
239 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
243 int i, desclength = 0, namelen;
245 namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
247 /* Either "Boot" or "Driver" followed by four digits of hex */
248 for (i = match; i < match+4; i++) {
249 if (var->VariableName[i] > 127 ||
250 hex_to_bin(var->VariableName[i] & 0xff) < 0)
254 /* Reject it if there's 4 digits of hex and then further content */
255 if (namelen > match + 4)
258 /* A valid entry must be at least 8 bytes */
262 filepathlength = buffer[4] | buffer[5] << 8;
265 * There's no stored length for the description, so it has to be
268 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
270 /* Each boot entry must have a descriptor */
275 * If the sum of the length of the description, the claimed filepath
276 * length and the original header are greater than the length of the
277 * variable, it's malformed
279 if ((desclength + filepathlength + 6) > len)
283 * And, finally, check the filepath
285 return validate_device_path(var, match, buffer + desclength + 6,
290 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
293 /* A single 16-bit integer */
301 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
306 for (i = 0; i < len; i++) {
317 struct variable_validate {
319 bool (*validate)(struct efi_variable *var, int match, u8 *data,
323 static const struct variable_validate variable_validate[] = {
324 { "BootNext", validate_uint16 },
325 { "BootOrder", validate_boot_order },
326 { "DriverOrder", validate_boot_order },
327 { "Boot*", validate_load_option },
328 { "Driver*", validate_load_option },
329 { "ConIn", validate_device_path },
330 { "ConInDev", validate_device_path },
331 { "ConOut", validate_device_path },
332 { "ConOutDev", validate_device_path },
333 { "ErrOut", validate_device_path },
334 { "ErrOutDev", validate_device_path },
335 { "Timeout", validate_uint16 },
336 { "Lang", validate_ascii_string },
337 { "PlatformLang", validate_ascii_string },
342 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
345 u16 *unicode_name = var->VariableName;
347 for (i = 0; variable_validate[i].validate != NULL; i++) {
348 const char *name = variable_validate[i].name;
351 for (match = 0; ; match++) {
352 char c = name[match];
353 u16 u = unicode_name[match];
355 /* All special variables are plain ascii */
359 /* Wildcard in the matching name means we've matched */
361 return variable_validate[i].validate(var,
364 /* Case sensitive match */
368 /* Reached the end of the string while matching */
370 return variable_validate[i].validate(var,
379 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
383 var->DataSize = 1024;
384 status = efivars->ops->get_variable(var->VariableName,
393 get_var_data(struct efivars *efivars, struct efi_variable *var)
397 spin_lock(&efivars->lock);
398 status = get_var_data_locked(efivars, var);
399 spin_unlock(&efivars->lock);
401 if (status != EFI_SUCCESS) {
402 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
409 efivar_guid_read(struct efivar_entry *entry, char *buf)
411 struct efi_variable *var = &entry->var;
417 efi_guid_unparse(&var->VendorGuid, str);
419 str += sprintf(str, "\n");
425 efivar_attr_read(struct efivar_entry *entry, char *buf)
427 struct efi_variable *var = &entry->var;
434 status = get_var_data(entry->efivars, var);
435 if (status != EFI_SUCCESS)
438 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
439 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
440 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
441 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
442 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
443 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
444 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
445 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
446 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
448 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
449 if (var->Attributes &
450 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
452 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
453 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
454 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
459 efivar_size_read(struct efivar_entry *entry, char *buf)
461 struct efi_variable *var = &entry->var;
468 status = get_var_data(entry->efivars, var);
469 if (status != EFI_SUCCESS)
472 str += sprintf(str, "0x%lx\n", var->DataSize);
477 efivar_data_read(struct efivar_entry *entry, char *buf)
479 struct efi_variable *var = &entry->var;
485 status = get_var_data(entry->efivars, var);
486 if (status != EFI_SUCCESS)
489 memcpy(buf, var->Data, var->DataSize);
490 return var->DataSize;
493 * We allow each variable to be edited via rewriting the
494 * entire efi variable structure.
497 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
499 struct efi_variable *new_var, *var = &entry->var;
500 struct efivars *efivars = entry->efivars;
501 efi_status_t status = EFI_NOT_FOUND;
503 if (count != sizeof(struct efi_variable))
506 new_var = (struct efi_variable *)buf;
508 * If only updating the variable data, then the name
509 * and guid should remain the same
511 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
512 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
513 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
517 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
518 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
522 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
523 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
524 printk(KERN_ERR "efivars: Malformed variable content\n");
528 spin_lock(&efivars->lock);
529 status = efivars->ops->set_variable(new_var->VariableName,
530 &new_var->VendorGuid,
535 spin_unlock(&efivars->lock);
537 if (status != EFI_SUCCESS) {
538 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
543 memcpy(&entry->var, new_var, count);
548 efivar_show_raw(struct efivar_entry *entry, char *buf)
550 struct efi_variable *var = &entry->var;
556 status = get_var_data(entry->efivars, var);
557 if (status != EFI_SUCCESS)
560 memcpy(buf, var, sizeof(*var));
565 * Generic read/write functions that call the specific functions of
568 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
571 struct efivar_entry *var = to_efivar_entry(kobj);
572 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
575 if (!capable(CAP_SYS_ADMIN))
578 if (efivar_attr->show) {
579 ret = efivar_attr->show(var, buf);
584 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
585 const char *buf, size_t count)
587 struct efivar_entry *var = to_efivar_entry(kobj);
588 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
591 if (!capable(CAP_SYS_ADMIN))
594 if (efivar_attr->store)
595 ret = efivar_attr->store(var, buf, count);
600 static const struct sysfs_ops efivar_attr_ops = {
601 .show = efivar_attr_show,
602 .store = efivar_attr_store,
605 static void efivar_release(struct kobject *kobj)
607 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
611 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
612 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
613 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
614 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
615 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
617 static struct attribute *def_attrs[] = {
618 &efivar_attr_guid.attr,
619 &efivar_attr_size.attr,
620 &efivar_attr_attributes.attr,
621 &efivar_attr_data.attr,
622 &efivar_attr_raw_var.attr,
626 static struct kobj_type efivar_ktype = {
627 .release = efivar_release,
628 .sysfs_ops = &efivar_attr_ops,
629 .default_attrs = def_attrs,
632 static struct pstore_info efi_pstore_info;
635 efivar_unregister(struct efivar_entry *var)
637 kobject_put(&var->kobj);
642 static int efi_pstore_open(struct pstore_info *psi)
644 struct efivars *efivars = psi->data;
646 spin_lock(&efivars->lock);
647 efivars->walk_entry = list_first_entry(&efivars->list,
648 struct efivar_entry, list);
652 static int efi_pstore_close(struct pstore_info *psi)
654 struct efivars *efivars = psi->data;
656 spin_unlock(&efivars->lock);
660 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
661 int *count, struct timespec *timespec,
662 char **buf, struct pstore_info *psi)
664 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
665 struct efivars *efivars = psi->data;
666 char name[DUMP_NAME_LEN];
669 unsigned int part, size;
672 while (&efivars->walk_entry->list != &efivars->list) {
673 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
675 for (i = 0; i < DUMP_NAME_LEN; i++) {
676 name[i] = efivars->walk_entry->var.VariableName[i];
678 if (sscanf(name, "dump-type%u-%u-%d-%lu",
679 type, &part, &cnt, &time) == 4) {
682 timespec->tv_sec = time;
683 timespec->tv_nsec = 0;
684 } else if (sscanf(name, "dump-type%u-%u-%lu",
685 type, &part, &time) == 3) {
687 * Check if an old format,
688 * which doesn't support holding
689 * multiple logs, remains.
693 timespec->tv_sec = time;
694 timespec->tv_nsec = 0;
696 efivars->walk_entry = list_entry(
697 efivars->walk_entry->list.next,
698 struct efivar_entry, list);
702 get_var_data_locked(efivars, &efivars->walk_entry->var);
703 size = efivars->walk_entry->var.DataSize;
704 *buf = kmalloc(size, GFP_KERNEL);
707 memcpy(*buf, efivars->walk_entry->var.Data,
709 efivars->walk_entry = list_entry(
710 efivars->walk_entry->list.next,
711 struct efivar_entry, list);
714 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
715 struct efivar_entry, list);
720 static int efi_pstore_write(enum pstore_type_id type,
721 enum kmsg_dump_reason reason, u64 *id,
722 unsigned int part, int count, size_t size,
723 struct pstore_info *psi)
725 char name[DUMP_NAME_LEN];
726 efi_char16_t efi_name[DUMP_NAME_LEN];
727 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
728 struct efivars *efivars = psi->data;
730 u64 storage_space, remaining_space, max_variable_size;
731 efi_status_t status = EFI_NOT_FOUND;
733 spin_lock(&efivars->lock);
736 * Check if there is a space enough to log.
737 * size: a size of logging data
738 * DUMP_NAME_LEN * 2: a maximum size of variable name
740 status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
744 if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
745 spin_unlock(&efivars->lock);
750 sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
753 for (i = 0; i < DUMP_NAME_LEN; i++)
754 efi_name[i] = name[i];
756 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
759 spin_unlock(&efivars->lock);
762 ret = efivar_create_sysfs_entry(efivars,
763 utf16_strsize(efi_name,
771 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
772 struct timespec time, struct pstore_info *psi)
774 char name[DUMP_NAME_LEN];
775 efi_char16_t efi_name[DUMP_NAME_LEN];
776 char name_old[DUMP_NAME_LEN];
777 efi_char16_t efi_name_old[DUMP_NAME_LEN];
778 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
779 struct efivars *efivars = psi->data;
780 struct efivar_entry *entry, *found = NULL;
783 sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
786 spin_lock(&efivars->lock);
788 for (i = 0; i < DUMP_NAME_LEN; i++)
789 efi_name[i] = name[i];
792 * Clean up an entry with the same name
795 list_for_each_entry(entry, &efivars->list, list) {
796 get_var_data_locked(efivars, &entry->var);
798 if (efi_guidcmp(entry->var.VendorGuid, vendor))
800 if (utf16_strncmp(entry->var.VariableName, efi_name,
801 utf16_strlen(efi_name))) {
803 * Check if an old format,
804 * which doesn't support holding
805 * multiple logs, remains.
807 sprintf(name_old, "dump-type%u-%u-%lu", type,
808 (unsigned int)id, time.tv_sec);
810 for (i = 0; i < DUMP_NAME_LEN; i++)
811 efi_name_old[i] = name_old[i];
813 if (utf16_strncmp(entry->var.VariableName, efi_name_old,
814 utf16_strlen(efi_name_old)))
820 efivars->ops->set_variable(entry->var.VariableName,
821 &entry->var.VendorGuid,
822 PSTORE_EFI_ATTRIBUTES,
828 list_del(&found->list);
830 spin_unlock(&efivars->lock);
833 efivar_unregister(found);
838 static int efi_pstore_open(struct pstore_info *psi)
843 static int efi_pstore_close(struct pstore_info *psi)
848 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
849 struct timespec *timespec,
850 char **buf, struct pstore_info *psi)
855 static int efi_pstore_write(enum pstore_type_id type,
856 enum kmsg_dump_reason reason, u64 *id,
857 unsigned int part, int count, size_t size,
858 struct pstore_info *psi)
863 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
864 struct timespec time, struct pstore_info *psi)
870 static struct pstore_info efi_pstore_info = {
871 .owner = THIS_MODULE,
873 .open = efi_pstore_open,
874 .close = efi_pstore_close,
875 .read = efi_pstore_read,
876 .write = efi_pstore_write,
877 .erase = efi_pstore_erase,
880 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
881 struct bin_attribute *bin_attr,
882 char *buf, loff_t pos, size_t count)
884 struct efi_variable *new_var = (struct efi_variable *)buf;
885 struct efivars *efivars = bin_attr->private;
886 struct efivar_entry *search_efivar, *n;
887 unsigned long strsize1, strsize2;
888 efi_status_t status = EFI_NOT_FOUND;
891 if (!capable(CAP_SYS_ADMIN))
894 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
895 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
896 printk(KERN_ERR "efivars: Malformed variable content\n");
900 spin_lock(&efivars->lock);
903 * Does this variable already exist?
905 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
906 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
907 strsize2 = utf16_strsize(new_var->VariableName, 1024);
908 if (strsize1 == strsize2 &&
909 !memcmp(&(search_efivar->var.VariableName),
910 new_var->VariableName, strsize1) &&
911 !efi_guidcmp(search_efivar->var.VendorGuid,
912 new_var->VendorGuid)) {
918 spin_unlock(&efivars->lock);
922 /* now *really* create the variable via EFI */
923 status = efivars->ops->set_variable(new_var->VariableName,
924 &new_var->VendorGuid,
929 if (status != EFI_SUCCESS) {
930 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
932 spin_unlock(&efivars->lock);
935 spin_unlock(&efivars->lock);
937 /* Create the entry in sysfs. Locking is not required here */
938 status = efivar_create_sysfs_entry(efivars,
939 utf16_strsize(new_var->VariableName,
941 new_var->VariableName,
942 &new_var->VendorGuid);
944 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
949 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
950 struct bin_attribute *bin_attr,
951 char *buf, loff_t pos, size_t count)
953 struct efi_variable *del_var = (struct efi_variable *)buf;
954 struct efivars *efivars = bin_attr->private;
955 struct efivar_entry *search_efivar, *n;
956 unsigned long strsize1, strsize2;
957 efi_status_t status = EFI_NOT_FOUND;
960 if (!capable(CAP_SYS_ADMIN))
963 spin_lock(&efivars->lock);
966 * Does this variable already exist?
968 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
969 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
970 strsize2 = utf16_strsize(del_var->VariableName, 1024);
971 if (strsize1 == strsize2 &&
972 !memcmp(&(search_efivar->var.VariableName),
973 del_var->VariableName, strsize1) &&
974 !efi_guidcmp(search_efivar->var.VendorGuid,
975 del_var->VendorGuid)) {
981 spin_unlock(&efivars->lock);
984 /* force the Attributes/DataSize to 0 to ensure deletion */
985 del_var->Attributes = 0;
986 del_var->DataSize = 0;
988 status = efivars->ops->set_variable(del_var->VariableName,
989 &del_var->VendorGuid,
994 if (status != EFI_SUCCESS) {
995 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
997 spin_unlock(&efivars->lock);
1000 list_del(&search_efivar->list);
1001 /* We need to release this lock before unregistering. */
1002 spin_unlock(&efivars->lock);
1003 efivar_unregister(search_efivar);
1005 /* It's dead Jim.... */
1010 * Let's not leave out systab information that snuck into
1011 * the efivars driver
1013 static ssize_t systab_show(struct kobject *kobj,
1014 struct kobj_attribute *attr, char *buf)
1021 if (efi.mps != EFI_INVALID_TABLE_ADDR)
1022 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1023 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1024 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1025 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1026 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1027 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1028 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1029 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1030 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1031 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1032 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1033 if (efi.uga != EFI_INVALID_TABLE_ADDR)
1034 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1039 static struct kobj_attribute efi_attr_systab =
1040 __ATTR(systab, 0400, systab_show, NULL);
1042 static struct attribute *efi_subsys_attrs[] = {
1043 &efi_attr_systab.attr,
1044 NULL, /* maybe more in the future? */
1047 static struct attribute_group efi_subsys_attr_group = {
1048 .attrs = efi_subsys_attrs,
1051 static struct kobject *efi_kobj;
1054 * efivar_create_sysfs_entry()
1056 * variable_name_size = number of bytes required to hold
1057 * variable_name (not counting the NULL
1058 * character at the end.
1059 * efivars->lock is not held on entry or exit.
1060 * Returns 1 on failure, 0 on success
1063 efivar_create_sysfs_entry(struct efivars *efivars,
1064 unsigned long variable_name_size,
1065 efi_char16_t *variable_name,
1066 efi_guid_t *vendor_guid)
1068 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1070 struct efivar_entry *new_efivar;
1072 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1073 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1075 if (!short_name || !new_efivar) {
1081 new_efivar->efivars = efivars;
1082 memcpy(new_efivar->var.VariableName, variable_name,
1083 variable_name_size);
1084 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1086 /* Convert Unicode to normal chars (assume top bits are 0),
1088 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1089 short_name[i] = variable_name[i] & 0xFF;
1091 /* This is ugly, but necessary to separate one vendor's
1092 private variables from another's. */
1094 *(short_name + strlen(short_name)) = '-';
1095 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1097 new_efivar->kobj.kset = efivars->kset;
1098 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1106 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1110 spin_lock(&efivars->lock);
1111 list_add(&new_efivar->list, &efivars->list);
1112 spin_unlock(&efivars->lock);
1118 create_efivars_bin_attributes(struct efivars *efivars)
1120 struct bin_attribute *attr;
1124 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1128 attr->attr.name = "new_var";
1129 attr->attr.mode = 0200;
1130 attr->write = efivar_create;
1131 attr->private = efivars;
1132 efivars->new_var = attr;
1135 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1140 attr->attr.name = "del_var";
1141 attr->attr.mode = 0200;
1142 attr->write = efivar_delete;
1143 attr->private = efivars;
1144 efivars->del_var = attr;
1146 sysfs_bin_attr_init(efivars->new_var);
1147 sysfs_bin_attr_init(efivars->del_var);
1150 error = sysfs_create_bin_file(&efivars->kset->kobj,
1153 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1154 " due to error %d\n", error);
1157 error = sysfs_create_bin_file(&efivars->kset->kobj,
1160 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1161 " due to error %d\n", error);
1162 sysfs_remove_bin_file(&efivars->kset->kobj,
1169 kfree(efivars->del_var);
1170 efivars->del_var = NULL;
1171 kfree(efivars->new_var);
1172 efivars->new_var = NULL;
1176 void unregister_efivars(struct efivars *efivars)
1178 struct efivar_entry *entry, *n;
1180 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1181 spin_lock(&efivars->lock);
1182 list_del(&entry->list);
1183 spin_unlock(&efivars->lock);
1184 efivar_unregister(entry);
1186 if (efivars->new_var)
1187 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1188 if (efivars->del_var)
1189 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1190 kfree(efivars->new_var);
1191 kfree(efivars->del_var);
1192 kset_unregister(efivars->kset);
1194 EXPORT_SYMBOL_GPL(unregister_efivars);
1196 int register_efivars(struct efivars *efivars,
1197 const struct efivar_operations *ops,
1198 struct kobject *parent_kobj)
1200 efi_status_t status = EFI_NOT_FOUND;
1201 efi_guid_t vendor_guid;
1202 efi_char16_t *variable_name;
1203 unsigned long variable_name_size = 1024;
1206 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1207 if (!variable_name) {
1208 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1212 spin_lock_init(&efivars->lock);
1213 INIT_LIST_HEAD(&efivars->list);
1216 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1217 if (!efivars->kset) {
1218 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1224 * Per EFI spec, the maximum storage allocated for both
1225 * the variable name and variable data is 1024 bytes.
1229 variable_name_size = 1024;
1231 status = ops->get_next_variable(&variable_name_size,
1236 efivar_create_sysfs_entry(efivars,
1244 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1246 status = EFI_NOT_FOUND;
1249 } while (status != EFI_NOT_FOUND);
1251 error = create_efivars_bin_attributes(efivars);
1253 unregister_efivars(efivars);
1255 efivars->efi_pstore_info = efi_pstore_info;
1257 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1258 if (efivars->efi_pstore_info.buf) {
1259 efivars->efi_pstore_info.bufsize = 1024;
1260 efivars->efi_pstore_info.data = efivars;
1261 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1262 pstore_register(&efivars->efi_pstore_info);
1266 kfree(variable_name);
1270 EXPORT_SYMBOL_GPL(register_efivars);
1272 static struct efivars __efivars;
1273 static struct efivar_operations ops;
1276 * For now we register the efi subsystem with the firmware subsystem
1277 * and the vars subsystem with the efi subsystem. In the future, it
1278 * might make sense to split off the efi subsystem into its own
1279 * driver, but for now only efivars will register with it, so just
1288 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1294 /* For now we'll register the efi directory at /sys/firmware/efi */
1295 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1297 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1301 ops.get_variable = efi.get_variable;
1302 ops.set_variable = efi.set_variable;
1303 ops.get_next_variable = efi.get_next_variable;
1304 ops.query_variable_info = efi.query_variable_info;
1305 error = register_efivars(&__efivars, &ops, efi_kobj);
1309 /* Don't forget the systab entry */
1310 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1313 "efivars: Sysfs attribute export failed with error %d.\n",
1315 goto err_unregister;
1321 unregister_efivars(&__efivars);
1323 kobject_put(efi_kobj);
1331 unregister_efivars(&__efivars);
1332 kobject_put(efi_kobj);
1336 module_init(efivars_init);
1337 module_exit(efivars_exit);