2 * efibc: control EFI bootloaders which obey LoaderEntryOneShot var
3 * Copyright (c) 2013-2016, Intel Corporation.
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 #define pr_fmt(fmt) "efibc: " fmt
17 #include <linux/efi.h>
18 #include <linux/module.h>
19 #include <linux/reboot.h>
21 static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
25 for (i = 0; i < strlen(str); i++)
31 static void efibc_set_variable(const char *name, const char *value)
34 efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
35 struct efivar_entry entry;
36 size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
38 if (size > sizeof(entry.var.Data))
39 pr_err("value is too large");
41 efibc_str_to_str16(name, entry.var.VariableName);
42 efibc_str_to_str16(value, (efi_char16_t *)entry.var.Data);
43 memcpy(&entry.var.VendorGuid, &guid, sizeof(guid));
45 ret = efivar_entry_set(&entry,
46 EFI_VARIABLE_NON_VOLATILE
47 | EFI_VARIABLE_BOOTSERVICE_ACCESS
48 | EFI_VARIABLE_RUNTIME_ACCESS,
49 size, entry.var.Data, NULL);
51 pr_err("failed to set %s EFI variable: 0x%x\n",
55 static int efibc_reboot_notifier_call(struct notifier_block *notifier,
56 unsigned long event, void *data)
58 const char *reason = "shutdown";
60 if (event == SYS_RESTART)
63 efibc_set_variable("LoaderEntryRebootReason", reason);
68 efibc_set_variable("LoaderEntryOneShot", (char *)data);
73 static struct notifier_block efibc_reboot_notifier = {
74 .notifier_call = efibc_reboot_notifier_call,
77 static int __init efibc_init(void)
81 if (!efi_enabled(EFI_RUNTIME_SERVICES))
84 ret = register_reboot_notifier(&efibc_reboot_notifier);
86 pr_err("unable to register reboot notifier\n");
90 module_init(efibc_init);
92 static void __exit efibc_exit(void)
94 unregister_reboot_notifier(&efibc_reboot_notifier);
96 module_exit(efibc_exit);
98 MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
99 MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
100 MODULE_DESCRIPTION("EFI Bootloader Control");
101 MODULE_LICENSE("GPL v2");