[mirror_ubuntu-artful-kernel.git] / drivers / firmware / efi / efibc.c

/*
 * efibc: control EFI bootloaders which obey LoaderEntryOneShot var
 * Copyright (c) 2013-2016, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */

#define pr_fmt(fmt) "efibc: " fmt

#include <linux/efi.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/slab.h>

static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
{
	size_t i;

	for (i = 0; i < strlen(str); i++)
		str16[i] = str[i];

	str16[i] = '\0';
}

static int efibc_set_variable(const char *name, const char *value)
{
	int ret;
	efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
	struct efivar_entry *entry;
	size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);

	if (size > sizeof(entry->var.Data)) {
		pr_err("value is too large (%zu bytes) for '%s' EFI variable\n", size, name);
		return -EINVAL;
	}

	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry) {
		pr_err("failed to allocate efivar entry for '%s' EFI variable\n", name);
		return -ENOMEM;
	}

	efibc_str_to_str16(name, entry->var.VariableName);
	efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
	memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));

	ret = efivar_entry_set(entry,
			       EFI_VARIABLE_NON_VOLATILE
			       | EFI_VARIABLE_BOOTSERVICE_ACCESS
			       | EFI_VARIABLE_RUNTIME_ACCESS,
			       size, entry->var.Data, NULL);
	if (ret)
		pr_err("failed to set %s EFI variable: 0x%x\n",
		       name, ret);

	kfree(entry);
	return ret;
}

static int efibc_reboot_notifier_call(struct notifier_block *notifier,
				      unsigned long event, void *data)
{
	const char *reason = "shutdown";
	int ret;

	if (event == SYS_RESTART)
		reason = "reboot";

	ret = efibc_set_variable("LoaderEntryRebootReason", reason);
	if (ret || !data)
		return NOTIFY_DONE;

	efibc_set_variable("LoaderEntryOneShot", (char *)data);

	return NOTIFY_DONE;
}

static struct notifier_block efibc_reboot_notifier = {
	.notifier_call = efibc_reboot_notifier_call,
};

static int __init efibc_init(void)
{
	int ret;

	if (!efi_enabled(EFI_RUNTIME_SERVICES))
		return -ENODEV;

	ret = register_reboot_notifier(&efibc_reboot_notifier);
	if (ret)
		pr_err("unable to register reboot notifier\n");

	return ret;
}
module_init(efibc_init);

static void __exit efibc_exit(void)
{
	unregister_reboot_notifier(&efibc_reboot_notifier);
}
module_exit(efibc_exit);

MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
MODULE_DESCRIPTION("EFI Bootloader Control");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
06f7d4a1 CJ	1	/*
	2	* efibc: control EFI bootloaders which obey LoaderEntryOneShot var
	3	* Copyright (c) 2013-2016, Intel Corporation.
	4	*
	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.
	8	*
	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
	12	* more details.
	13	*/
	14
	15	#define pr_fmt(fmt) "efibc: " fmt
	16
	17	#include <linux/efi.h>
	18	#include <linux/module.h>
	19	#include <linux/reboot.h>
2e121d71	20	#include <linux/slab.h>
06f7d4a1 CJ	21
	22	static void efibc_str_to_str16(const char str, efi_char16_t str16)
	23	{
	24	size_t i;
	25
	26	for (i = 0; i < strlen(str); i++)
	27	str16[i] = str[i];
	28
	29	str16[i] = '\0';
	30	}
	31
2e121d71	32	static int efibc_set_variable(const char name, const char value)
06f7d4a1 CJ	33	{
	34	int ret;
	35	efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
2e121d71	36	struct efivar_entry *entry;
06f7d4a1 CJ	37	size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
06f7d4a1 CJ	38
2e121d71	39	if (size > sizeof(entry->var.Data)) {
5356c327	40	pr_err("value is too large (%zu bytes) for '%s' EFI variable\n", size, name);
2e121d71 JC	41	return -EINVAL;
2e121d71 JC	42	}
06f7d4a1	43
2e121d71 JC	44	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2e121d71 JC	45	if (!entry) {
5356c327	46	pr_err("failed to allocate efivar entry for '%s' EFI variable\n", name);
2e121d71 JC	47	return -ENOMEM;
2e121d71 JC	48	}
06f7d4a1	49
2e121d71 JC	50	efibc_str_to_str16(name, entry->var.VariableName);
	51	efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
	52	memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
	53
	54	ret = efivar_entry_set(entry,
06f7d4a1 CJ	55	EFI_VARIABLE_NON_VOLATILE
	56	\| EFI_VARIABLE_BOOTSERVICE_ACCESS
	57	\| EFI_VARIABLE_RUNTIME_ACCESS,
2e121d71	58	size, entry->var.Data, NULL);
06f7d4a1 CJ	59	if (ret)
	60	pr_err("failed to set %s EFI variable: 0x%x\n",
	61	name, ret);
2e121d71 JC	62
	63	kfree(entry);
	64	return ret;
06f7d4a1 CJ	65	}
	66
	67	static int efibc_reboot_notifier_call(struct notifier_block *notifier,
	68	unsigned long event, void *data)
	69	{
	70	const char *reason = "shutdown";
2e121d71	71	int ret;
06f7d4a1 CJ	72
	73	if (event == SYS_RESTART)
	74	reason = "reboot";
	75
2e121d71 JC	76	ret = efibc_set_variable("LoaderEntryRebootReason", reason);
2e121d71 JC	77	if (ret \|\| !data)
06f7d4a1 CJ	78	return NOTIFY_DONE;
	79
	80	efibc_set_variable("LoaderEntryOneShot", (char *)data);
	81
	82	return NOTIFY_DONE;
	83	}
	84
	85	static struct notifier_block efibc_reboot_notifier = {
	86	.notifier_call = efibc_reboot_notifier_call,
	87	};
	88
	89	static int __init efibc_init(void)
	90	{
	91	int ret;
	92
	93	if (!efi_enabled(EFI_RUNTIME_SERVICES))
	94	return -ENODEV;
	95
	96	ret = register_reboot_notifier(&efibc_reboot_notifier);
	97	if (ret)
	98	pr_err("unable to register reboot notifier\n");
	99
	100	return ret;
	101	}
	102	module_init(efibc_init);
	103
	104	static void __exit efibc_exit(void)
	105	{
	106	unregister_reboot_notifier(&efibc_reboot_notifier);
	107	}
	108	module_exit(efibc_exit);
	109
	110	MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
	111	MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
	112	MODULE_DESCRIPTION("EFI Bootloader Control");
	113	MODULE_LICENSE("GPL v2");