drivers/acpi/acpi_configfs.c

   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
  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
  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
  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
  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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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");