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
 16static struct config_group *acpi_table_group;
 17
 18struct acpi_table {
 19	struct config_item cfg;
 20	struct acpi_table_header *header;
 21	u32 index;
 22};
 23
 24static 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
 66static 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
 76static 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
 92CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
 93
 94static struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
 95	&acpi_table_attr_aml,
 96	NULL,
 97};
 98
 99static 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
109static 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
119static 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
129static 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
139static 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
149static 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
159static 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
170static 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
181CONFIGFS_ATTR_RO(acpi_table_, signature);
182CONFIGFS_ATTR_RO(acpi_table_, length);
183CONFIGFS_ATTR_RO(acpi_table_, revision);
184CONFIGFS_ATTR_RO(acpi_table_, oem_id);
185CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
186CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
187CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
188CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
189
190static 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
202static 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
208static 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
221static 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
231static struct configfs_group_operations acpi_table_group_ops = {
232	.make_item = acpi_table_make_item,
233	.drop_item = acpi_table_drop_item,
234};
235
236static const struct config_item_type acpi_tables_type = {
237	.ct_owner = THIS_MODULE,
238	.ct_group_ops = &acpi_table_group_ops,
239};
240
241static const struct config_item_type acpi_root_group_type = {
242	.ct_owner = THIS_MODULE,
243};
244
245static 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
255static 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}
275module_init(acpi_configfs_init);
276
277static void __exit acpi_configfs_exit(void)
278{
279	configfs_unregister_default_group(acpi_table_group);
280	configfs_unregister_subsystem(&acpi_configfs);
281}
282module_exit(acpi_configfs_exit);
283
284MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
285MODULE_DESCRIPTION("ACPI configfs support");
286MODULE_LICENSE("GPL v2");