xref: /openbmc/linux/drivers/acpi/acpi_configfs.c (revision 45c16fe1)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ACPI configfs support
4  *
5  * Copyright (c) 2016 Intel Corporation
6  */
7 
8 #define pr_fmt(fmt) "ACPI configfs: " fmt
9 
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/configfs.h>
13 #include <linux/acpi.h>
14 #include <linux/security.h>
15 
16 static struct config_group *acpi_table_group;
17 
18 struct acpi_table {
19 	struct config_item cfg;
20 	struct acpi_table_header *header;
21 	u32 index;
22 };
23 
acpi_table_aml_write(struct config_item * cfg,const void * data,size_t size)24 static ssize_t acpi_table_aml_write(struct config_item *cfg,
25 				    const void *data, size_t size)
26 {
27 	const struct acpi_table_header *header = data;
28 	struct acpi_table *table;
29 	int ret = security_locked_down(LOCKDOWN_ACPI_TABLES);
30 
31 	if (ret)
32 		return ret;
33 
34 	table = container_of(cfg, struct acpi_table, cfg);
35 
36 	if (table->header) {
37 		pr_err("table already loaded\n");
38 		return -EBUSY;
39 	}
40 
41 	if (header->length != size) {
42 		pr_err("invalid table length\n");
43 		return -EINVAL;
44 	}
45 
46 	if (memcmp(header->signature, ACPI_SIG_SSDT, 4)) {
47 		pr_err("invalid table signature\n");
48 		return -EINVAL;
49 	}
50 
51 	table = container_of(cfg, struct acpi_table, cfg);
52 
53 	table->header = kmemdup(header, header->length, GFP_KERNEL);
54 	if (!table->header)
55 		return -ENOMEM;
56 
57 	ret = acpi_load_table(table->header, &table->index);
58 	if (ret) {
59 		kfree(table->header);
60 		table->header = NULL;
61 	}
62 
63 	return ret;
64 }
65 
get_header(struct config_item * cfg)66 static inline struct acpi_table_header *get_header(struct config_item *cfg)
67 {
68 	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
69 
70 	if (!table->header)
71 		pr_err("table not loaded\n");
72 
73 	return table->header ?: ERR_PTR(-EINVAL);
74 }
75 
acpi_table_aml_read(struct config_item * cfg,void * data,size_t size)76 static ssize_t acpi_table_aml_read(struct config_item *cfg,
77 				   void *data, size_t size)
78 {
79 	struct acpi_table_header *h = get_header(cfg);
80 
81 	if (IS_ERR(h))
82 		return PTR_ERR(h);
83 
84 	if (data)
85 		memcpy(data, h, h->length);
86 
87 	return h->length;
88 }
89 
90 #define MAX_ACPI_TABLE_SIZE (128 * 1024)
91 
92 CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
93 
94 static struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
95 	&acpi_table_attr_aml,
96 	NULL,
97 };
98 
acpi_table_signature_show(struct config_item * cfg,char * str)99 static ssize_t acpi_table_signature_show(struct config_item *cfg, char *str)
100 {
101 	struct acpi_table_header *h = get_header(cfg);
102 
103 	if (IS_ERR(h))
104 		return PTR_ERR(h);
105 
106 	return sysfs_emit(str, "%.*s\n", ACPI_NAMESEG_SIZE, h->signature);
107 }
108 
acpi_table_length_show(struct config_item * cfg,char * str)109 static ssize_t acpi_table_length_show(struct config_item *cfg, char *str)
110 {
111 	struct acpi_table_header *h = get_header(cfg);
112 
113 	if (IS_ERR(h))
114 		return PTR_ERR(h);
115 
116 	return sysfs_emit(str, "%d\n", h->length);
117 }
118 
acpi_table_revision_show(struct config_item * cfg,char * str)119 static ssize_t acpi_table_revision_show(struct config_item *cfg, char *str)
120 {
121 	struct acpi_table_header *h = get_header(cfg);
122 
123 	if (IS_ERR(h))
124 		return PTR_ERR(h);
125 
126 	return sysfs_emit(str, "%d\n", h->revision);
127 }
128 
acpi_table_oem_id_show(struct config_item * cfg,char * str)129 static ssize_t acpi_table_oem_id_show(struct config_item *cfg, char *str)
130 {
131 	struct acpi_table_header *h = get_header(cfg);
132 
133 	if (IS_ERR(h))
134 		return PTR_ERR(h);
135 
136 	return sysfs_emit(str, "%.*s\n", ACPI_OEM_ID_SIZE, h->oem_id);
137 }
138 
acpi_table_oem_table_id_show(struct config_item * cfg,char * str)139 static ssize_t acpi_table_oem_table_id_show(struct config_item *cfg, char *str)
140 {
141 	struct acpi_table_header *h = get_header(cfg);
142 
143 	if (IS_ERR(h))
144 		return PTR_ERR(h);
145 
146 	return sysfs_emit(str, "%.*s\n", ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id);
147 }
148 
acpi_table_oem_revision_show(struct config_item * cfg,char * str)149 static ssize_t acpi_table_oem_revision_show(struct config_item *cfg, char *str)
150 {
151 	struct acpi_table_header *h = get_header(cfg);
152 
153 	if (IS_ERR(h))
154 		return PTR_ERR(h);
155 
156 	return sysfs_emit(str, "%d\n", h->oem_revision);
157 }
158 
acpi_table_asl_compiler_id_show(struct config_item * cfg,char * str)159 static ssize_t acpi_table_asl_compiler_id_show(struct config_item *cfg,
160 					       char *str)
161 {
162 	struct acpi_table_header *h = get_header(cfg);
163 
164 	if (IS_ERR(h))
165 		return PTR_ERR(h);
166 
167 	return sysfs_emit(str, "%.*s\n", ACPI_NAMESEG_SIZE, h->asl_compiler_id);
168 }
169 
acpi_table_asl_compiler_revision_show(struct config_item * cfg,char * str)170 static ssize_t acpi_table_asl_compiler_revision_show(struct config_item *cfg,
171 						     char *str)
172 {
173 	struct acpi_table_header *h = get_header(cfg);
174 
175 	if (IS_ERR(h))
176 		return PTR_ERR(h);
177 
178 	return sysfs_emit(str, "%d\n", h->asl_compiler_revision);
179 }
180 
181 CONFIGFS_ATTR_RO(acpi_table_, signature);
182 CONFIGFS_ATTR_RO(acpi_table_, length);
183 CONFIGFS_ATTR_RO(acpi_table_, revision);
184 CONFIGFS_ATTR_RO(acpi_table_, oem_id);
185 CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
186 CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
187 CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
188 CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
189 
190 static struct configfs_attribute *acpi_table_attrs[] = {
191 	&acpi_table_attr_signature,
192 	&acpi_table_attr_length,
193 	&acpi_table_attr_revision,
194 	&acpi_table_attr_oem_id,
195 	&acpi_table_attr_oem_table_id,
196 	&acpi_table_attr_oem_revision,
197 	&acpi_table_attr_asl_compiler_id,
198 	&acpi_table_attr_asl_compiler_revision,
199 	NULL,
200 };
201 
202 static const struct config_item_type acpi_table_type = {
203 	.ct_owner = THIS_MODULE,
204 	.ct_bin_attrs = acpi_table_bin_attrs,
205 	.ct_attrs = acpi_table_attrs,
206 };
207 
acpi_table_make_item(struct config_group * group,const char * name)208 static struct config_item *acpi_table_make_item(struct config_group *group,
209 						const char *name)
210 {
211 	struct acpi_table *table;
212 
213 	table = kzalloc(sizeof(*table), GFP_KERNEL);
214 	if (!table)
215 		return ERR_PTR(-ENOMEM);
216 
217 	config_item_init_type_name(&table->cfg, name, &acpi_table_type);
218 	return &table->cfg;
219 }
220 
acpi_table_drop_item(struct config_group * group,struct config_item * cfg)221 static void acpi_table_drop_item(struct config_group *group,
222 				 struct config_item *cfg)
223 {
224 	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
225 
226 	pr_debug("Host-directed Dynamic ACPI Table Unload\n");
227 	acpi_unload_table(table->index);
228 	config_item_put(cfg);
229 }
230 
231 static struct configfs_group_operations acpi_table_group_ops = {
232 	.make_item = acpi_table_make_item,
233 	.drop_item = acpi_table_drop_item,
234 };
235 
236 static const struct config_item_type acpi_tables_type = {
237 	.ct_owner = THIS_MODULE,
238 	.ct_group_ops = &acpi_table_group_ops,
239 };
240 
241 static const struct config_item_type acpi_root_group_type = {
242 	.ct_owner = THIS_MODULE,
243 };
244 
245 static struct configfs_subsystem acpi_configfs = {
246 	.su_group = {
247 		.cg_item = {
248 			.ci_namebuf = "acpi",
249 			.ci_type = &acpi_root_group_type,
250 		},
251 	},
252 	.su_mutex = __MUTEX_INITIALIZER(acpi_configfs.su_mutex),
253 };
254 
acpi_configfs_init(void)255 static int __init acpi_configfs_init(void)
256 {
257 	int ret;
258 	struct config_group *root = &acpi_configfs.su_group;
259 
260 	config_group_init(root);
261 
262 	ret = configfs_register_subsystem(&acpi_configfs);
263 	if (ret)
264 		return ret;
265 
266 	acpi_table_group = configfs_register_default_group(root, "table",
267 							   &acpi_tables_type);
268 	if (IS_ERR(acpi_table_group)) {
269 		configfs_unregister_subsystem(&acpi_configfs);
270 		return PTR_ERR(acpi_table_group);
271 	}
272 
273 	return 0;
274 }
275 module_init(acpi_configfs_init);
276 
acpi_configfs_exit(void)277 static void __exit acpi_configfs_exit(void)
278 {
279 	configfs_unregister_default_group(acpi_table_group);
280 	configfs_unregister_subsystem(&acpi_configfs);
281 }
282 module_exit(acpi_configfs_exit);
283 
284 MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
285 MODULE_DESCRIPTION("ACPI configfs support");
286 MODULE_LICENSE("GPL v2");
287