summaryrefslogtreecommitdiff
path: root/drivers/firmware/efi/efi.c
blob: e1010d450b659fd1e11570633394726b4525fc67 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/*
 * efi.c - EFI subsystem
 *
 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
 * Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
 *
 * This code registers /sys/firmware/efi{,/efivars} when EFI is supported,
 * allowing the efivarfs to be mounted or the efivars module to be loaded.
 * The existance of /sys/firmware/efi may also be used by userspace to
 * determine that the system supports EFI.
 *
 * This file is released under the GPLv2.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/efi.h>
#include <linux/io.h>

struct efi __read_mostly efi = {
	.mps        = EFI_INVALID_TABLE_ADDR,
	.acpi       = EFI_INVALID_TABLE_ADDR,
	.acpi20     = EFI_INVALID_TABLE_ADDR,
	.smbios     = EFI_INVALID_TABLE_ADDR,
	.sal_systab = EFI_INVALID_TABLE_ADDR,
	.boot_info  = EFI_INVALID_TABLE_ADDR,
	.hcdp       = EFI_INVALID_TABLE_ADDR,
	.uga        = EFI_INVALID_TABLE_ADDR,
	.uv_systab  = EFI_INVALID_TABLE_ADDR,
};
EXPORT_SYMBOL(efi);

static struct kobject *efi_kobj;
static struct kobject *efivars_kobj;

/*
 * Let's not leave out systab information that snuck into
 * the efivars driver
 */
static ssize_t systab_show(struct kobject *kobj,
			   struct kobj_attribute *attr, char *buf)
{
	char *str = buf;

	if (!kobj || !buf)
		return -EINVAL;

	if (efi.mps != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "MPS=0x%lx\n", efi.mps);
	if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
	if (efi.acpi != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
	if (efi.smbios != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
	if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
	if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
	if (efi.uga != EFI_INVALID_TABLE_ADDR)
		str += sprintf(str, "UGA=0x%lx\n", efi.uga);

	return str - buf;
}

static struct kobj_attribute efi_attr_systab =
			__ATTR(systab, 0400, systab_show, NULL);

static struct attribute *efi_subsys_attrs[] = {
	&efi_attr_systab.attr,
	NULL,	/* maybe more in the future? */
};

static struct attribute_group efi_subsys_attr_group = {
	.attrs = efi_subsys_attrs,
};

static struct efivars generic_efivars;
static struct efivar_operations generic_ops;

static int generic_ops_register(void)
{
	generic_ops.get_variable = efi.get_variable;
	generic_ops.set_variable = efi.set_variable;
	generic_ops.get_next_variable = efi.get_next_variable;
	generic_ops.query_variable_store = efi_query_variable_store;

	return efivars_register(&generic_efivars, &generic_ops, efi_kobj);
}

static void generic_ops_unregister(void)
{
	efivars_unregister(&generic_efivars);
}

/*
 * We register the efi subsystem with the firmware subsystem and the
 * efivars subsystem with the efi subsystem, if the system was booted with
 * EFI.
 */
static int __init efisubsys_init(void)
{
	int error;

	if (!efi_enabled(EFI_BOOT))
		return 0;

	/* We register the efi directory at /sys/firmware/efi */
	efi_kobj = kobject_create_and_add("efi", firmware_kobj);
	if (!efi_kobj) {
		pr_err("efi: Firmware registration failed.\n");
		return -ENOMEM;
	}

	error = generic_ops_register();
	if (error)
		goto err_put;

	error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
	if (error) {
		pr_err("efi: Sysfs attribute export failed with error %d.\n",
		       error);
		goto err_unregister;
	}

	/* and the standard mountpoint for efivarfs */
	efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
	if (!efivars_kobj) {
		pr_err("efivars: Subsystem registration failed.\n");
		error = -ENOMEM;
		goto err_remove_group;
	}

	return 0;

err_remove_group:
	sysfs_remove_group(efi_kobj, &efi_subsys_attr_group);
err_unregister:
	generic_ops_unregister();
err_put:
	kobject_put(efi_kobj);
	return error;
}

subsys_initcall(efisubsys_init);


static __initdata efi_config_table_type_t common_tables[] = {
	{ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
	{ACPI_TABLE_GUID, "ACPI", &efi.acpi},
	{HCDP_TABLE_GUID, "HCDP", &efi.hcdp},
	{MPS_TABLE_GUID, "MPS", &efi.mps},
	{SAL_SYSTEM_TABLE_GUID, "SALsystab", &efi.sal_systab},
	{SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
	{UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga},
	{NULL_GUID, NULL, 0},
};

static __init int match_config_table(efi_guid_t *guid,
				     unsigned long table,
				     efi_config_table_type_t *table_types)
{
	u8 str[EFI_VARIABLE_GUID_LEN + 1];
	int i;

	if (table_types) {
		efi_guid_unparse(guid, str);

		for (i = 0; efi_guidcmp(table_types[i].guid, NULL_GUID); i++) {
			efi_guid_unparse(&table_types[i].guid, str);

			if (!efi_guidcmp(*guid, table_types[i].guid)) {
				*(table_types[i].ptr) = table;
				pr_cont(" %s=0x%lx ",
					table_types[i].name, table);
				return 1;
			}
		}
	}

	return 0;
}

int __init efi_config_init(efi_config_table_type_t *arch_tables)
{
	void *config_tables, *tablep;
	int i, sz;

	if (efi_enabled(EFI_64BIT))
		sz = sizeof(efi_config_table_64_t);
	else
		sz = sizeof(efi_config_table_32_t);

	/*
	 * Let's see what config tables the firmware passed to us.
	 */
	config_tables = early_memremap(efi.systab->tables,
				       efi.systab->nr_tables * sz);
	if (config_tables == NULL) {
		pr_err("Could not map Configuration table!\n");
		return -ENOMEM;
	}

	tablep = config_tables;
	pr_info("");
	for (i = 0; i < efi.systab->nr_tables; i++) {
		efi_guid_t guid;
		unsigned long table;

		if (efi_enabled(EFI_64BIT)) {
			u64 table64;
			guid = ((efi_config_table_64_t *)tablep)->guid;
			table64 = ((efi_config_table_64_t *)tablep)->table;
			table = table64;
#ifndef CONFIG_64BIT
			if (table64 >> 32) {
				pr_cont("\n");
				pr_err("Table located above 4GB, disabling EFI.\n");
				early_iounmap(config_tables,
					       efi.systab->nr_tables * sz);
				return -EINVAL;
			}
#endif
		} else {
			guid = ((efi_config_table_32_t *)tablep)->guid;
			table = ((efi_config_table_32_t *)tablep)->table;
		}

		if (!match_config_table(&guid, table, common_tables))
			match_config_table(&guid, table, arch_tables);

		tablep += sz;
	}
	pr_cont("\n");
	early_iounmap(config_tables, efi.systab->nr_tables * sz);
	return 0;
}