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