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 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];
668 unsigned int part, size;
671 while (&efivars->walk_entry->list != &efivars->list) {
672 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
674 for (i = 0; i < DUMP_NAME_LEN; i++) {
675 name[i] = efivars->walk_entry->var.VariableName[i];
677 if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
679 timespec->tv_sec = time;
680 timespec->tv_nsec = 0;
681 get_var_data_locked(efivars, &efivars->walk_entry->var);
682 size = efivars->walk_entry->var.DataSize;
683 *buf = kmalloc(size, GFP_KERNEL);
686 memcpy(*buf, efivars->walk_entry->var.Data,
688 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
689 struct efivar_entry, list);
693 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
694 struct efivar_entry, list);
699 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
700 unsigned int part, size_t size, struct pstore_info *psi)
702 char name[DUMP_NAME_LEN];
703 char stub_name[DUMP_NAME_LEN];
704 efi_char16_t efi_name[DUMP_NAME_LEN];
705 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
706 struct efivars *efivars = psi->data;
707 struct efivar_entry *entry, *found = NULL;
710 sprintf(stub_name, "dump-type%u-%u-", type, part);
711 sprintf(name, "%s%lu", stub_name, get_seconds());
713 spin_lock(&efivars->lock);
715 for (i = 0; i < DUMP_NAME_LEN; i++)
716 efi_name[i] = stub_name[i];
719 * Clean up any entries with the same name
722 list_for_each_entry(entry, &efivars->list, list) {
723 get_var_data_locked(efivars, &entry->var);
725 if (efi_guidcmp(entry->var.VendorGuid, vendor))
727 if (utf16_strncmp(entry->var.VariableName, efi_name,
728 utf16_strlen(efi_name)))
730 /* Needs to be a prefix */
731 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
736 efivars->ops->set_variable(entry->var.VariableName,
737 &entry->var.VendorGuid,
738 PSTORE_EFI_ATTRIBUTES,
743 list_del(&found->list);
745 for (i = 0; i < DUMP_NAME_LEN; i++)
746 efi_name[i] = name[i];
748 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
751 spin_unlock(&efivars->lock);
754 efivar_unregister(found);
757 ret = efivar_create_sysfs_entry(efivars,
758 utf16_strsize(efi_name,
766 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
767 struct pstore_info *psi)
769 efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
774 static int efi_pstore_open(struct pstore_info *psi)
779 static int efi_pstore_close(struct pstore_info *psi)
784 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
785 struct timespec *timespec,
786 char **buf, struct pstore_info *psi)
791 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
792 unsigned int part, size_t size, struct pstore_info *psi)
797 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
798 struct pstore_info *psi)
804 static struct pstore_info efi_pstore_info = {
805 .owner = THIS_MODULE,
807 .open = efi_pstore_open,
808 .close = efi_pstore_close,
809 .read = efi_pstore_read,
810 .write = efi_pstore_write,
811 .erase = efi_pstore_erase,
814 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
815 struct bin_attribute *bin_attr,
816 char *buf, loff_t pos, size_t count)
818 struct efi_variable *new_var = (struct efi_variable *)buf;
819 struct efivars *efivars = bin_attr->private;
820 struct efivar_entry *search_efivar, *n;
821 unsigned long strsize1, strsize2;
822 efi_status_t status = EFI_NOT_FOUND;
825 if (!capable(CAP_SYS_ADMIN))
828 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
829 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
830 printk(KERN_ERR "efivars: Malformed variable content\n");
834 spin_lock(&efivars->lock);
837 * Does this variable already exist?
839 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
840 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
841 strsize2 = utf16_strsize(new_var->VariableName, 1024);
842 if (strsize1 == strsize2 &&
843 !memcmp(&(search_efivar->var.VariableName),
844 new_var->VariableName, strsize1) &&
845 !efi_guidcmp(search_efivar->var.VendorGuid,
846 new_var->VendorGuid)) {
852 spin_unlock(&efivars->lock);
856 /* now *really* create the variable via EFI */
857 status = efivars->ops->set_variable(new_var->VariableName,
858 &new_var->VendorGuid,
863 if (status != EFI_SUCCESS) {
864 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
866 spin_unlock(&efivars->lock);
869 spin_unlock(&efivars->lock);
871 /* Create the entry in sysfs. Locking is not required here */
872 status = efivar_create_sysfs_entry(efivars,
873 utf16_strsize(new_var->VariableName,
875 new_var->VariableName,
876 &new_var->VendorGuid);
878 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
883 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
884 struct bin_attribute *bin_attr,
885 char *buf, loff_t pos, size_t count)
887 struct efi_variable *del_var = (struct efi_variable *)buf;
888 struct efivars *efivars = bin_attr->private;
889 struct efivar_entry *search_efivar, *n;
890 unsigned long strsize1, strsize2;
891 efi_status_t status = EFI_NOT_FOUND;
894 if (!capable(CAP_SYS_ADMIN))
897 spin_lock(&efivars->lock);
900 * Does this variable already exist?
902 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
903 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
904 strsize2 = utf16_strsize(del_var->VariableName, 1024);
905 if (strsize1 == strsize2 &&
906 !memcmp(&(search_efivar->var.VariableName),
907 del_var->VariableName, strsize1) &&
908 !efi_guidcmp(search_efivar->var.VendorGuid,
909 del_var->VendorGuid)) {
915 spin_unlock(&efivars->lock);
918 /* force the Attributes/DataSize to 0 to ensure deletion */
919 del_var->Attributes = 0;
920 del_var->DataSize = 0;
922 status = efivars->ops->set_variable(del_var->VariableName,
923 &del_var->VendorGuid,
928 if (status != EFI_SUCCESS) {
929 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
931 spin_unlock(&efivars->lock);
934 list_del(&search_efivar->list);
935 /* We need to release this lock before unregistering. */
936 spin_unlock(&efivars->lock);
937 efivar_unregister(search_efivar);
939 /* It's dead Jim.... */
944 * Let's not leave out systab information that snuck into
947 static ssize_t systab_show(struct kobject *kobj,
948 struct kobj_attribute *attr, char *buf)
955 if (efi.mps != EFI_INVALID_TABLE_ADDR)
956 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
957 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
958 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
959 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
960 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
961 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
962 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
963 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
964 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
965 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
966 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
967 if (efi.uga != EFI_INVALID_TABLE_ADDR)
968 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
973 static struct kobj_attribute efi_attr_systab =
974 __ATTR(systab, 0400, systab_show, NULL);
976 static struct attribute *efi_subsys_attrs[] = {
977 &efi_attr_systab.attr,
978 NULL, /* maybe more in the future? */
981 static struct attribute_group efi_subsys_attr_group = {
982 .attrs = efi_subsys_attrs,
985 static struct kobject *efi_kobj;
988 * efivar_create_sysfs_entry()
990 * variable_name_size = number of bytes required to hold
991 * variable_name (not counting the NULL
992 * character at the end.
993 * efivars->lock is not held on entry or exit.
994 * Returns 1 on failure, 0 on success
997 efivar_create_sysfs_entry(struct efivars *efivars,
998 unsigned long variable_name_size,
999 efi_char16_t *variable_name,
1000 efi_guid_t *vendor_guid)
1002 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1004 struct efivar_entry *new_efivar;
1006 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1007 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1009 if (!short_name || !new_efivar) {
1015 new_efivar->efivars = efivars;
1016 memcpy(new_efivar->var.VariableName, variable_name,
1017 variable_name_size);
1018 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1020 /* Convert Unicode to normal chars (assume top bits are 0),
1022 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1023 short_name[i] = variable_name[i] & 0xFF;
1025 /* This is ugly, but necessary to separate one vendor's
1026 private variables from another's. */
1028 *(short_name + strlen(short_name)) = '-';
1029 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1031 new_efivar->kobj.kset = efivars->kset;
1032 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1040 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1044 spin_lock(&efivars->lock);
1045 list_add(&new_efivar->list, &efivars->list);
1046 spin_unlock(&efivars->lock);
1052 create_efivars_bin_attributes(struct efivars *efivars)
1054 struct bin_attribute *attr;
1058 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1062 attr->attr.name = "new_var";
1063 attr->attr.mode = 0200;
1064 attr->write = efivar_create;
1065 attr->private = efivars;
1066 efivars->new_var = attr;
1069 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1074 attr->attr.name = "del_var";
1075 attr->attr.mode = 0200;
1076 attr->write = efivar_delete;
1077 attr->private = efivars;
1078 efivars->del_var = attr;
1080 sysfs_bin_attr_init(efivars->new_var);
1081 sysfs_bin_attr_init(efivars->del_var);
1084 error = sysfs_create_bin_file(&efivars->kset->kobj,
1087 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1088 " due to error %d\n", error);
1091 error = sysfs_create_bin_file(&efivars->kset->kobj,
1094 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1095 " due to error %d\n", error);
1096 sysfs_remove_bin_file(&efivars->kset->kobj,
1103 kfree(efivars->del_var);
1104 efivars->del_var = NULL;
1105 kfree(efivars->new_var);
1106 efivars->new_var = NULL;
1110 void unregister_efivars(struct efivars *efivars)
1112 struct efivar_entry *entry, *n;
1114 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1115 spin_lock(&efivars->lock);
1116 list_del(&entry->list);
1117 spin_unlock(&efivars->lock);
1118 efivar_unregister(entry);
1120 if (efivars->new_var)
1121 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1122 if (efivars->del_var)
1123 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1124 kfree(efivars->new_var);
1125 kfree(efivars->del_var);
1126 kset_unregister(efivars->kset);
1128 EXPORT_SYMBOL_GPL(unregister_efivars);
1130 int register_efivars(struct efivars *efivars,
1131 const struct efivar_operations *ops,
1132 struct kobject *parent_kobj)
1134 efi_status_t status = EFI_NOT_FOUND;
1135 efi_guid_t vendor_guid;
1136 efi_char16_t *variable_name;
1137 unsigned long variable_name_size = 1024;
1140 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1141 if (!variable_name) {
1142 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1146 spin_lock_init(&efivars->lock);
1147 INIT_LIST_HEAD(&efivars->list);
1150 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1151 if (!efivars->kset) {
1152 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1158 * Per EFI spec, the maximum storage allocated for both
1159 * the variable name and variable data is 1024 bytes.
1163 variable_name_size = 1024;
1165 status = ops->get_next_variable(&variable_name_size,
1170 efivar_create_sysfs_entry(efivars,
1178 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1180 status = EFI_NOT_FOUND;
1183 } while (status != EFI_NOT_FOUND);
1185 error = create_efivars_bin_attributes(efivars);
1187 unregister_efivars(efivars);
1189 efivars->efi_pstore_info = efi_pstore_info;
1191 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1192 if (efivars->efi_pstore_info.buf) {
1193 efivars->efi_pstore_info.bufsize = 1024;
1194 efivars->efi_pstore_info.data = efivars;
1195 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1196 pstore_register(&efivars->efi_pstore_info);
1200 kfree(variable_name);
1204 EXPORT_SYMBOL_GPL(register_efivars);
1206 static struct efivars __efivars;
1207 static struct efivar_operations ops;
1210 * For now we register the efi subsystem with the firmware subsystem
1211 * and the vars subsystem with the efi subsystem. In the future, it
1212 * might make sense to split off the efi subsystem into its own
1213 * driver, but for now only efivars will register with it, so just
1222 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1225 if (!efi_enabled(EFI_RUNTIME_SERVICES))
1228 /* For now we'll register the efi directory at /sys/firmware/efi */
1229 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1231 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1235 ops.get_variable = efi.get_variable;
1236 ops.set_variable = efi.set_variable;
1237 ops.get_next_variable = efi.get_next_variable;
1238 error = register_efivars(&__efivars, &ops, efi_kobj);
1242 /* Don't forget the systab entry */
1243 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1246 "efivars: Sysfs attribute export failed with error %d.\n",
1248 goto err_unregister;
1254 unregister_efivars(&__efivars);
1256 kobject_put(efi_kobj);
1263 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1264 unregister_efivars(&__efivars);
1265 kobject_put(efi_kobj);
1269 module_init(efivars_init);
1270 module_exit(efivars_exit);