ACPI: add support for loading SSDTs via configfs (612bd01f) · Commits · 戴 / test

Documentation/ABI/testing/configfs-acpi

+29 −0

Original line number	Diff line number	Diff line
		@@ -5,3 +5,32 @@ Contact: linux-acpi@vger.kernel.org
		Description:
		This represents the ACPI subsystem entry point directory. It
		contains sub-groups corresponding to ACPI configurable options.

		What: /config/acpi/table
		Date: July 2016
		KernelVersion: 4.8
		Description:

		This group contains the configuration for user defined ACPI
		tables. The attributes of a user define table are:

		aml - a binary attribute that the user can use to
		fill in the ACPI aml definitions. Once the aml
		data is written to this file and the file is
		closed the table will be loaded and ACPI devices
		will be enumerated. To check if the operation is
		successful the user must check the error code
		for close(). If the operation is successful,
		subsequent writes to this attribute will fail.

		The rest of the attributes are read-only and are valid only
		after the table has been loaded by filling the aml entry:

		signature - ASCII table signature
		length - length of table in bytes, including the header
		revision - ACPI Specification minor version number
		oem_id - ASCII OEM identification
		oem_table_id - ASCII OEM table identification
		oem_revision - OEM revision number
		asl_compiler_id - ASCII ASL compiler vendor ID
		asl_compiler_revision - ASL compiler version

Documentation/acpi/ssdt-overlays.txt

+14 −0

Original line number	Diff line number	Diff line
		@@ -156,3 +156,17 @@ tmp=$(mktemp)
		/bin/echo -ne "\007\000\000\000" \| cat - $filename > $tmp
		dd if=$tmp of="$EFIVARFS/$name-$guid" bs=$(stat -c %s $tmp)
		rm $tmp

		== Loading ACPI SSDTs from configfs ==

		This option allows loading of user defined SSDTs from userspace via the configfs
		interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be
		mounted. In the following examples, we assume that configfs has been mounted in
		/config.

		New tables can be loading by creating new directories in /config/acpi/table/ and
		writing the SSDT aml code in the aml attribute:

		cd /config/acpi/table
		mkdir my_ssdt
		cat ~/ssdt.aml > my_ssdt/aml

drivers/acpi/configfs.c

+215 −1

Original line number	Diff line number	Diff line
		@@ -8,11 +8,222 @@
		* the Free Software Foundation.
		*/

		#define pr_fmt(fmt) "ACPI configfs: " fmt

		#include <linux/init.h>
		#include <linux/module.h>
		#include <linux/configfs.h>
		#include <linux/acpi.h>

		static struct config_group *acpi_table_group;

		struct acpi_table {
		struct config_item cfg;
		struct acpi_table_header *header;
		};

		static ssize_t acpi_table_aml_write(struct config_item *cfg,
		const void *data, size_t size)
		{
		const struct acpi_table_header *header = data;
		struct acpi_table *table;
		int ret;

		table = container_of(cfg, struct acpi_table, cfg);

		if (table->header) {
		pr_err("table already loaded\n");
		return -EBUSY;
		}

		if (header->length != size) {
		pr_err("invalid table length\n");
		return -EINVAL;
		}

		if (memcmp(header->signature, ACPI_SIG_SSDT, 4)) {
		pr_err("invalid table signature\n");
		return -EINVAL;
		}

		table = container_of(cfg, struct acpi_table, cfg);

		table->header = kmemdup(header, header->length, GFP_KERNEL);
		if (!table->header)
		return -ENOMEM;

		ret = acpi_load_table(table->header);
		if (ret) {
		kfree(table->header);
		table->header = NULL;
		}

		return ret;
		}

		static inline struct acpi_table_header get_header(struct config_item cfg)
		{
		struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);

		if (!table->header)
		pr_err("table not loaded\n");

		return table->header;
		}

		static ssize_t acpi_table_aml_read(struct config_item *cfg,
		void *data, size_t size)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		if (data)
		memcpy(data, h, h->length);

		return h->length;
		}

		#define MAX_ACPI_TABLE_SIZE (128 * 1024)

		CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);

		struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
		&acpi_table_attr_aml,
		NULL,
		};

		ssize_t acpi_table_signature_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->signature);
		}

		ssize_t acpi_table_length_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%d\n", h->length);
		}

		ssize_t acpi_table_revision_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%d\n", h->revision);
		}

		ssize_t acpi_table_oem_id_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%.*s\n", ACPI_OEM_ID_SIZE, h->oem_id);
		}

		ssize_t acpi_table_oem_table_id_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%.*s\n", ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id);
		}

		ssize_t acpi_table_oem_revision_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%d\n", h->oem_revision);
		}

		ssize_t acpi_table_asl_compiler_id_show(struct config_item cfg, char str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->asl_compiler_id);
		}

		ssize_t acpi_table_asl_compiler_revision_show(struct config_item *cfg,
		char *str)
		{
		struct acpi_table_header *h = get_header(cfg);

		if (!h)
		return -EINVAL;

		return sprintf(str, "%d\n", h->asl_compiler_revision);
		}

		CONFIGFS_ATTR_RO(acpi_table_, signature);
		CONFIGFS_ATTR_RO(acpi_table_, length);
		CONFIGFS_ATTR_RO(acpi_table_, revision);
		CONFIGFS_ATTR_RO(acpi_table_, oem_id);
		CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
		CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
		CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
		CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);

		struct configfs_attribute *acpi_table_attrs[] = {
		&acpi_table_attr_signature,
		&acpi_table_attr_length,
		&acpi_table_attr_revision,
		&acpi_table_attr_oem_id,
		&acpi_table_attr_oem_table_id,
		&acpi_table_attr_oem_revision,
		&acpi_table_attr_asl_compiler_id,
		&acpi_table_attr_asl_compiler_revision,
		NULL,
		};

		static struct config_item_type acpi_table_type = {
		.ct_owner = THIS_MODULE,
		.ct_bin_attrs = acpi_table_bin_attrs,
		.ct_attrs = acpi_table_attrs,
		};

		static struct config_item acpi_table_make_item(struct config_group group,
		const char *name)
		{
		struct acpi_table *table;

		table = kzalloc(sizeof(*table), GFP_KERNEL);
		if (!table)
		return ERR_PTR(-ENOMEM);

		config_item_init_type_name(&table->cfg, name, &acpi_table_type);
		return &table->cfg;
		}

		struct configfs_group_operations acpi_table_group_ops = {
		.make_item = acpi_table_make_item,
		};

		static struct config_item_type acpi_tables_type = {
		.ct_owner = THIS_MODULE,
		.ct_group_ops = &acpi_table_group_ops,
		};

		static struct config_item_type acpi_root_group_type = {
		.ct_owner = THIS_MODULE,
		};
		@@ -38,12 +249,15 @@ static int __init acpi_configfs_init(void)
		if (ret)
		return ret;

		return 0;
		acpi_table_group = configfs_register_default_group(root, "table",
		&acpi_tables_type);
		return PTR_ERR_OR_ZERO(acpi_table_group);
		}
		module_init(acpi_configfs_init);

		static void __exit acpi_configfs_exit(void)
		{
		configfs_unregister_default_group(acpi_table_group);
		configfs_unregister_subsystem(&acpi_configfs);
		}
		module_exit(acpi_configfs_exit);

Admin message