287 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ACPI configfs support4 *5 * Copyright (c) 2016 Intel Corporation6 */7 8#define pr_fmt(fmt) "ACPI configfs: " fmt9 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");287