1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * efibc: control EFI bootloaders which obey LoaderEntryOneShot var
 4 * Copyright (c) 2013-2016, Intel Corporation.
 5 */
 6
 7#define pr_fmt(fmt) "efibc: " fmt
 8
 9#include <linux/efi.h>
10#include <linux/module.h>
11#include <linux/reboot.h>
12#include <linux/slab.h>
13#include <linux/ucs2_string.h>
14
15#define MAX_DATA_LEN	512
16
17static int efibc_set_variable(efi_char16_t *name, efi_char16_t *value,
18			      unsigned long len)
19{
20	efi_status_t status;
21
22	status = efi.set_variable(name, &LINUX_EFI_LOADER_ENTRY_GUID,
23				  EFI_VARIABLE_NON_VOLATILE
24				  | EFI_VARIABLE_BOOTSERVICE_ACCESS
25				  | EFI_VARIABLE_RUNTIME_ACCESS,
26				  len * sizeof(efi_char16_t), value);
27
28	if (status != EFI_SUCCESS) {
29		pr_err("failed to set EFI variable: 0x%lx\n", status);
30		return -EIO;
31	}
32	return 0;
33}
34
35static int efibc_reboot_notifier_call(struct notifier_block *notifier,
36				      unsigned long event, void *data)
37{
38	efi_char16_t *reason = event == SYS_RESTART ? L"reboot"
39						    : L"shutdown";
40	const u8 *str = data;
41	efi_char16_t *wdata;
42	unsigned long l;
43	int ret;
44
45	ret = efibc_set_variable(L"LoaderEntryRebootReason", reason,
46				 ucs2_strlen(reason));
47	if (ret || !data)
48		return NOTIFY_DONE;
49
50	wdata = kmalloc(MAX_DATA_LEN * sizeof(efi_char16_t), GFP_KERNEL);
51	if (!wdata)
52		return NOTIFY_DONE;
53
54	for (l = 0; l < MAX_DATA_LEN - 1 && str[l] != '\0'; l++)
55		wdata[l] = str[l];
56	wdata[l] = L'\0';
57
58	efibc_set_variable(L"LoaderEntryOneShot", wdata, l);
59
60	kfree(wdata);
61	return NOTIFY_DONE;
62}
63
64static struct notifier_block efibc_reboot_notifier = {
65	.notifier_call = efibc_reboot_notifier_call,
66};
67
68static int __init efibc_init(void)
69{
70	int ret;
71
72	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
73		return -ENODEV;
74
75	ret = register_reboot_notifier(&efibc_reboot_notifier);
76	if (ret)
77		pr_err("unable to register reboot notifier\n");
78
79	return ret;
80}
81module_init(efibc_init);
82
83static void __exit efibc_exit(void)
84{
85	unregister_reboot_notifier(&efibc_reboot_notifier);
86}
87module_exit(efibc_exit);
88
89MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
90MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
91MODULE_DESCRIPTION("EFI Bootloader Control");
92MODULE_LICENSE("GPL v2");

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * efibc: control EFI bootloaders which obey LoaderEntryOneShot var
 4 * Copyright (c) 2013-2016, Intel Corporation.
 5 */
 6
 7#define pr_fmt(fmt) "efibc: " fmt
 8
 9#include <linux/efi.h>
10#include <linux/module.h>
11#include <linux/reboot.h>
12#include <linux/slab.h>
13#include <linux/ucs2_string.h>
14
15#define MAX_DATA_LEN	512
16
17static int efibc_set_variable(efi_char16_t *name, efi_char16_t *value,
18			      unsigned long len)
19{
20	efi_status_t status;
21
22	status = efi.set_variable(name, &LINUX_EFI_LOADER_ENTRY_GUID,
23				  EFI_VARIABLE_NON_VOLATILE
24				  | EFI_VARIABLE_BOOTSERVICE_ACCESS
25				  | EFI_VARIABLE_RUNTIME_ACCESS,
26				  len * sizeof(efi_char16_t), value);
27
28	if (status != EFI_SUCCESS) {
29		pr_err("failed to set EFI variable: 0x%lx\n", status);
30		return -EIO;
31	}
32	return 0;
33}
34
35static int efibc_reboot_notifier_call(struct notifier_block *notifier,
36				      unsigned long event, void *data)
37{
38	efi_char16_t *reason = event == SYS_RESTART ? L"reboot"
39						    : L"shutdown";
40	const u8 *str = data;
41	efi_char16_t *wdata;
42	unsigned long l;
43	int ret;
44
45	ret = efibc_set_variable(L"LoaderEntryRebootReason", reason,
46				 ucs2_strlen(reason));
47	if (ret || !data)
48		return NOTIFY_DONE;
49
50	wdata = kmalloc(MAX_DATA_LEN * sizeof(efi_char16_t), GFP_KERNEL);
51	if (!wdata)
52		return NOTIFY_DONE;
53
54	for (l = 0; l < MAX_DATA_LEN - 1 && str[l] != '\0'; l++)
55		wdata[l] = str[l];
56	wdata[l] = L'\0';
57
58	efibc_set_variable(L"LoaderEntryOneShot", wdata, l);
59
60	kfree(wdata);
61	return NOTIFY_DONE;
62}
63
64static struct notifier_block efibc_reboot_notifier = {
65	.notifier_call = efibc_reboot_notifier_call,
66};
67
68static int __init efibc_init(void)
69{
70	int ret;
71
72	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
73		return -ENODEV;
74
75	ret = register_reboot_notifier(&efibc_reboot_notifier);
76	if (ret)
77		pr_err("unable to register reboot notifier\n");
78
79	return ret;
80}
81module_init(efibc_init);
82
83static void __exit efibc_exit(void)
84{
85	unregister_reboot_notifier(&efibc_reboot_notifier);
86}
87module_exit(efibc_exit);
88
89MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
90MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
91MODULE_DESCRIPTION("EFI Bootloader Control");
92MODULE_LICENSE("GPL v2");