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 *; |
21 | u32 index; |
22 | }; |
23 | |
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 * = data; |
28 | struct acpi_table *table; |
29 | int ret = security_locked_down(what: 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(p: header->signature, ACPI_SIG_SSDT, size: 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(p: header, size: header->length, GFP_KERNEL); |
54 | if (!table->header) |
55 | return -ENOMEM; |
56 | |
57 | ret = acpi_load_table(table: table->header, table_idx: &table->index); |
58 | if (ret) { |
59 | kfree(objp: table->header); |
60 | table->header = NULL; |
61 | } |
62 | |
63 | return ret; |
64 | } |
65 | |
66 | static inline struct acpi_table_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(error: -EINVAL); |
74 | } |
75 | |
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(ptr: h)) |
82 | return PTR_ERR(ptr: 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 | |
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(ptr: h)) |
104 | return PTR_ERR(ptr: h); |
105 | |
106 | return sysfs_emit(buf: str, fmt: "%.*s\n" , ACPI_NAMESEG_SIZE, h->signature); |
107 | } |
108 | |
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(ptr: h)) |
114 | return PTR_ERR(ptr: h); |
115 | |
116 | return sysfs_emit(buf: str, fmt: "%d\n" , h->length); |
117 | } |
118 | |
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(ptr: h)) |
124 | return PTR_ERR(ptr: h); |
125 | |
126 | return sysfs_emit(buf: str, fmt: "%d\n" , h->revision); |
127 | } |
128 | |
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(ptr: h)) |
134 | return PTR_ERR(ptr: h); |
135 | |
136 | return sysfs_emit(buf: str, fmt: "%.*s\n" , ACPI_OEM_ID_SIZE, h->oem_id); |
137 | } |
138 | |
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(ptr: h)) |
144 | return PTR_ERR(ptr: h); |
145 | |
146 | return sysfs_emit(buf: str, fmt: "%.*s\n" , ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id); |
147 | } |
148 | |
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(ptr: h)) |
154 | return PTR_ERR(ptr: h); |
155 | |
156 | return sysfs_emit(buf: str, fmt: "%d\n" , h->oem_revision); |
157 | } |
158 | |
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(ptr: h)) |
165 | return PTR_ERR(ptr: h); |
166 | |
167 | return sysfs_emit(buf: str, fmt: "%.*s\n" , ACPI_NAMESEG_SIZE, h->asl_compiler_id); |
168 | } |
169 | |
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(ptr: h)) |
176 | return PTR_ERR(ptr: h); |
177 | |
178 | return sysfs_emit(buf: str, fmt: "%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 | |
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(size: sizeof(*table), GFP_KERNEL); |
214 | if (!table) |
215 | return ERR_PTR(error: -ENOMEM); |
216 | |
217 | config_item_init_type_name(item: &table->cfg, name, type: &acpi_table_type); |
218 | return &table->cfg; |
219 | } |
220 | |
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: 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 | |
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(group: root); |
261 | |
262 | ret = configfs_register_subsystem(subsys: &acpi_configfs); |
263 | if (ret) |
264 | return ret; |
265 | |
266 | acpi_table_group = configfs_register_default_group(parent_group: root, name: "table" , |
267 | item_type: &acpi_tables_type); |
268 | if (IS_ERR(ptr: acpi_table_group)) { |
269 | configfs_unregister_subsystem(subsys: &acpi_configfs); |
270 | return PTR_ERR(ptr: acpi_table_group); |
271 | } |
272 | |
273 | return 0; |
274 | } |
275 | module_init(acpi_configfs_init); |
276 | |
277 | static void __exit acpi_configfs_exit(void) |
278 | { |
279 | configfs_unregister_default_group(group: acpi_table_group); |
280 | configfs_unregister_subsystem(subsys: &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 | |