2 * Originally from 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/efi.h>
69 #include <linux/module.h>
70 #include <linux/slab.h>
71 #include <linux/ucs2_string.h>
72 #include <linux/compat.h>
74 #define EFIVARS_VERSION "0.08"
75 #define EFIVARS_DATE "2004-May-17"
77 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
78 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
79 MODULE_LICENSE("GPL");
80 MODULE_VERSION(EFIVARS_VERSION);
82 LIST_HEAD(efivar_sysfs_list);
83 EXPORT_SYMBOL_GPL(efivar_sysfs_list);
85 static struct kset *efivars_kset;
87 static struct bin_attribute *efivars_new_var;
88 static struct bin_attribute *efivars_del_var;
90 struct compat_efi_variable {
91 efi_char16_t VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
92 efi_guid_t VendorGuid;
99 struct efivar_attribute {
100 struct attribute attr;
101 ssize_t (*show) (struct efivar_entry *entry, char *buf);
102 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
105 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
106 struct efivar_attribute efivar_attr_##_name = { \
107 .attr = {.name = __stringify(_name), .mode = _mode}, \
112 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
113 #define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
116 * Prototype for sysfs creation function
119 efivar_create_sysfs_entry(struct efivar_entry *new_var);
122 efivar_guid_read(struct efivar_entry *entry, char *buf)
124 struct efi_variable *var = &entry->var;
130 efi_guid_unparse(&var->VendorGuid, str);
132 str += sprintf(str, "\n");
138 efivar_attr_read(struct efivar_entry *entry, char *buf)
140 struct efi_variable *var = &entry->var;
146 var->DataSize = 1024;
147 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
150 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
151 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
152 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
153 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
154 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
155 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
156 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
157 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
158 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
160 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
161 if (var->Attributes &
162 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
164 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
165 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
166 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
171 efivar_size_read(struct efivar_entry *entry, char *buf)
173 struct efi_variable *var = &entry->var;
179 var->DataSize = 1024;
180 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
183 str += sprintf(str, "0x%lx\n", var->DataSize);
188 efivar_data_read(struct efivar_entry *entry, char *buf)
190 struct efi_variable *var = &entry->var;
195 var->DataSize = 1024;
196 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
199 memcpy(buf, var->Data, var->DataSize);
200 return var->DataSize;
204 sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
205 unsigned long size, u32 attributes, u8 *data)
208 * If only updating the variable data, then the name
209 * and guid should remain the same
211 if (memcmp(name, var->VariableName, sizeof(var->VariableName)) ||
212 efi_guidcmp(vendor, var->VendorGuid)) {
213 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
217 if ((size <= 0) || (attributes == 0)){
218 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
222 if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
223 efivar_validate(name, data, size) == false) {
224 printk(KERN_ERR "efivars: Malformed variable content\n");
231 static inline bool is_compat(void)
233 if (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())
240 copy_out_compat(struct efi_variable *dst, struct compat_efi_variable *src)
242 memcpy(dst->VariableName, src->VariableName, EFI_VAR_NAME_LEN);
243 memcpy(dst->Data, src->Data, sizeof(src->Data));
245 dst->VendorGuid = src->VendorGuid;
246 dst->DataSize = src->DataSize;
247 dst->Attributes = src->Attributes;
251 * We allow each variable to be edited via rewriting the
252 * entire efi variable structure.
255 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
257 struct efi_variable *new_var, *var = &entry->var;
266 struct compat_efi_variable *compat;
268 if (count != sizeof(*compat))
271 compat = (struct compat_efi_variable *)buf;
272 attributes = compat->Attributes;
273 vendor = compat->VendorGuid;
274 name = compat->VariableName;
275 size = compat->DataSize;
278 err = sanity_check(var, name, vendor, size, attributes, data);
282 copy_out_compat(&entry->var, compat);
284 if (count != sizeof(struct efi_variable))
287 new_var = (struct efi_variable *)buf;
289 attributes = new_var->Attributes;
290 vendor = new_var->VendorGuid;
291 name = new_var->VariableName;
292 size = new_var->DataSize;
293 data = new_var->Data;
295 err = sanity_check(var, name, vendor, size, attributes, data);
299 memcpy(&entry->var, new_var, count);
302 err = efivar_entry_set(entry, attributes, size, data, NULL);
304 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
312 efivar_show_raw(struct efivar_entry *entry, char *buf)
314 struct efi_variable *var = &entry->var;
315 struct compat_efi_variable *compat;
321 var->DataSize = 1024;
322 if (efivar_entry_get(entry, &entry->var.Attributes,
323 &entry->var.DataSize, entry->var.Data))
327 compat = (struct compat_efi_variable *)buf;
329 size = sizeof(*compat);
330 memcpy(compat->VariableName, var->VariableName,
332 memcpy(compat->Data, var->Data, sizeof(compat->Data));
334 compat->VendorGuid = var->VendorGuid;
335 compat->DataSize = var->DataSize;
336 compat->Attributes = var->Attributes;
339 memcpy(buf, var, size);
346 * Generic read/write functions that call the specific functions of
349 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
352 struct efivar_entry *var = to_efivar_entry(kobj);
353 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
356 if (!capable(CAP_SYS_ADMIN))
359 if (efivar_attr->show) {
360 ret = efivar_attr->show(var, buf);
365 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
366 const char *buf, size_t count)
368 struct efivar_entry *var = to_efivar_entry(kobj);
369 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
372 if (!capable(CAP_SYS_ADMIN))
375 if (efivar_attr->store)
376 ret = efivar_attr->store(var, buf, count);
381 static const struct sysfs_ops efivar_attr_ops = {
382 .show = efivar_attr_show,
383 .store = efivar_attr_store,
386 static void efivar_release(struct kobject *kobj)
388 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
392 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
393 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
394 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
395 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
396 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
398 static struct attribute *def_attrs[] = {
399 &efivar_attr_guid.attr,
400 &efivar_attr_size.attr,
401 &efivar_attr_attributes.attr,
402 &efivar_attr_data.attr,
403 &efivar_attr_raw_var.attr,
407 static struct kobj_type efivar_ktype = {
408 .release = efivar_release,
409 .sysfs_ops = &efivar_attr_ops,
410 .default_attrs = def_attrs,
413 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
414 struct bin_attribute *bin_attr,
415 char *buf, loff_t pos, size_t count)
417 struct compat_efi_variable *compat = (struct compat_efi_variable *)buf;
418 struct efi_variable *new_var = (struct efi_variable *)buf;
419 struct efivar_entry *new_entry;
420 bool need_compat = is_compat();
427 if (!capable(CAP_SYS_ADMIN))
431 if (count != sizeof(*compat))
434 attributes = compat->Attributes;
435 name = compat->VariableName;
436 size = compat->DataSize;
439 if (count != sizeof(*new_var))
442 attributes = new_var->Attributes;
443 name = new_var->VariableName;
444 size = new_var->DataSize;
445 data = new_var->Data;
448 if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
449 efivar_validate(name, data, size) == false) {
450 printk(KERN_ERR "efivars: Malformed variable content\n");
454 new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
459 copy_out_compat(&new_entry->var, compat);
461 memcpy(&new_entry->var, new_var, sizeof(*new_var));
463 err = efivar_entry_set(new_entry, attributes, size,
464 data, &efivar_sysfs_list);
471 if (efivar_create_sysfs_entry(new_entry)) {
472 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
482 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
483 struct bin_attribute *bin_attr,
484 char *buf, loff_t pos, size_t count)
486 struct efi_variable *del_var = (struct efi_variable *)buf;
487 struct compat_efi_variable *compat;
488 struct efivar_entry *entry;
493 if (!capable(CAP_SYS_ADMIN))
497 if (count != sizeof(*compat))
500 compat = (struct compat_efi_variable *)buf;
501 name = compat->VariableName;
502 vendor = compat->VendorGuid;
504 if (count != sizeof(*del_var))
507 name = del_var->VariableName;
508 vendor = del_var->VendorGuid;
511 efivar_entry_iter_begin();
512 entry = efivar_entry_find(name, vendor, &efivar_sysfs_list, true);
515 else if (__efivar_entry_delete(entry))
519 efivar_entry_iter_end();
523 if (!entry->scanning) {
524 efivar_entry_iter_end();
525 efivar_unregister(entry);
527 efivar_entry_iter_end();
529 /* It's dead Jim.... */
534 * efivar_create_sysfs_entry - create a new entry in sysfs
535 * @new_var: efivar entry to create
537 * Returns 1 on failure, 0 on success
540 efivar_create_sysfs_entry(struct efivar_entry *new_var)
542 int i, short_name_size;
544 unsigned long variable_name_size;
545 efi_char16_t *variable_name;
547 variable_name = new_var->var.VariableName;
548 variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
551 * Length of the variable bytes in ASCII, plus the '-' separator,
552 * plus the GUID, plus trailing NUL
554 short_name_size = variable_name_size / sizeof(efi_char16_t)
555 + 1 + EFI_VARIABLE_GUID_LEN + 1;
557 short_name = kzalloc(short_name_size, GFP_KERNEL);
562 /* Convert Unicode to normal chars (assume top bits are 0),
564 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
565 short_name[i] = variable_name[i] & 0xFF;
567 /* This is ugly, but necessary to separate one vendor's
568 private variables from another's. */
570 *(short_name + strlen(short_name)) = '-';
571 efi_guid_unparse(&new_var->var.VendorGuid,
572 short_name + strlen(short_name));
574 new_var->kobj.kset = efivars_kset;
576 i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
577 NULL, "%s", short_name);
582 kobject_uevent(&new_var->kobj, KOBJ_ADD);
583 efivar_entry_add(new_var, &efivar_sysfs_list);
589 create_efivars_bin_attributes(void)
591 struct bin_attribute *attr;
595 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
599 attr->attr.name = "new_var";
600 attr->attr.mode = 0200;
601 attr->write = efivar_create;
602 efivars_new_var = attr;
605 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
610 attr->attr.name = "del_var";
611 attr->attr.mode = 0200;
612 attr->write = efivar_delete;
613 efivars_del_var = attr;
615 sysfs_bin_attr_init(efivars_new_var);
616 sysfs_bin_attr_init(efivars_del_var);
619 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
621 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
622 " due to error %d\n", error);
626 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
628 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
629 " due to error %d\n", error);
630 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
636 kfree(efivars_del_var);
637 efivars_del_var = NULL;
638 kfree(efivars_new_var);
639 efivars_new_var = NULL;
643 static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
644 unsigned long name_size, void *data)
646 struct efivar_entry *entry = data;
648 if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
651 memcpy(entry->var.VariableName, name, name_size);
652 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
657 static void efivar_update_sysfs_entries(struct work_struct *work)
659 struct efivar_entry *entry;
662 /* Add new sysfs entries */
664 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
668 err = efivar_init(efivar_update_sysfs_entry, entry,
669 true, false, &efivar_sysfs_list);
673 efivar_create_sysfs_entry(entry);
679 static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
680 unsigned long name_size, void *data)
682 struct efivar_entry *entry;
684 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
688 memcpy(entry->var.VariableName, name, name_size);
689 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
691 efivar_create_sysfs_entry(entry);
696 static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
698 efivar_entry_remove(entry);
699 efivar_unregister(entry);
703 static void efivars_sysfs_exit(void)
705 /* Remove all entries and destroy */
706 __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
709 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
711 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
712 kfree(efivars_new_var);
713 kfree(efivars_del_var);
714 kset_unregister(efivars_kset);
717 int efivars_sysfs_init(void)
719 struct kobject *parent_kobj = efivars_kobject();
722 if (!efi_enabled(EFI_RUNTIME_SERVICES))
725 /* No efivars has been registered yet */
729 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
732 efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
734 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
738 efivar_init(efivars_sysfs_callback, NULL, false,
739 true, &efivar_sysfs_list);
741 error = create_efivars_bin_attributes();
743 efivars_sysfs_exit();
747 INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
751 EXPORT_SYMBOL_GPL(efivars_sysfs_init);
753 module_init(efivars_sysfs_init);
754 module_exit(efivars_sysfs_exit);