platform/x86: hp-bioscfg: int-attributes

Add integer attributes support to hp-bioscfg.

HP BIOS Configuration driver purpose is to provide a driver supporting
the latest sysfs class firmware attributes framework allowing the user
to change BIOS settings and security solutions on HP Inc.’s commercial
notebooks.
Signed-off-by: Jorge Lopez <jorge.lopez2@hp.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230608163319.18934-7-jorge.lopez2@hp.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/hp/hp-bioscfg/int-attributes.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to integer type attributes under
+ * BIOS Enumeration GUID for use with hp-bioscfg driver.
+ *
+ * Copyright (c) 2022 Hewlett-Packard Inc.
+ */
+
+#include "bioscfg.h"
+
+GET_INSTANCE_ID(integer);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id = get_integer_instance_id(kobj);
+
+	if (instance_id < 0)
+		return -EIO;
+
+	return sysfs_emit(buf, "%d\n",
+			  bioscfg_drv.integer_data[instance_id].current_value);
+}
+
+/**
+ * validate_integer_input() -
+ * Validate input of current_value against lower and upper bound
+ *
+ * @instance_id: The instance on which input is validated
+ * @buf: Input value
+ */
+static int validate_integer_input(int instance_id, char *buf)
+{
+	int in_val;
+	int ret;
+	struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
+
+	/* BIOS treats it as a read only attribute */
+	if (integer_data->common.is_readonly)
+		return -EIO;
+
+	ret = kstrtoint(buf, 10, &in_val);
+	if (ret < 0)
+		return ret;
+
+	if (in_val < integer_data->lower_bound ||
+	    in_val > integer_data->upper_bound)
+		return -ERANGE;
+
+	return 0;
+}
+
+static void update_integer_value(int instance_id, char *attr_value)
+{
+	int in_val;
+	int ret;
+	struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
+
+	ret = kstrtoint(attr_value, 10, &in_val);
+	if (ret == 0)
+		integer_data->current_value = in_val;
+	else
+		pr_warn("Invalid integer value found: %s\n", attr_value);
+}
+
+ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, integer);
+static struct kobj_attribute integer_display_name =
+	__ATTR_RO(display_name);
+
+ATTRIBUTE_PROPERTY_STORE(current_value, integer);
+static struct kobj_attribute integer_current_val =
+	__ATTR_RW_MODE(current_value, 0644);
+
+ATTRIBUTE_N_PROPERTY_SHOW(lower_bound, integer);
+static struct kobj_attribute integer_lower_bound =
+	__ATTR_RO(lower_bound);
+
+ATTRIBUTE_N_PROPERTY_SHOW(upper_bound, integer);
+static struct kobj_attribute integer_upper_bound =
+	__ATTR_RO(upper_bound);
+
+ATTRIBUTE_N_PROPERTY_SHOW(scalar_increment, integer);
+static struct kobj_attribute integer_scalar_increment =
+	__ATTR_RO(scalar_increment);
+
+static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	return sysfs_emit(buf, "integer\n");
+}
+
+static struct kobj_attribute integer_type =
+	__ATTR_RO(type);
+
+static struct attribute *integer_attrs[] = {
+	&common_display_langcode.attr,
+	&integer_display_name.attr,
+	&integer_current_val.attr,
+	&integer_lower_bound.attr,
+	&integer_upper_bound.attr,
+	&integer_scalar_increment.attr,
+	&integer_type.attr,
+	NULL
+};
+
+static const struct attribute_group integer_attr_group = {
+	.attrs = integer_attrs,
+};
+
+int hp_alloc_integer_data(void)
+{
+	bioscfg_drv.integer_instances_count = hp_get_instance_count(HP_WMI_BIOS_INTEGER_GUID);
+	bioscfg_drv.integer_data = kcalloc(bioscfg_drv.integer_instances_count,
+					   sizeof(*bioscfg_drv.integer_data), GFP_KERNEL);
+
+	if (!bioscfg_drv.integer_data) {
+		bioscfg_drv.integer_instances_count = 0;
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/* Expected Values types associated with each element */
+static const acpi_object_type expected_integer_types[] = {
+	[NAME] = ACPI_TYPE_STRING,
+	[VALUE] = ACPI_TYPE_STRING,
+	[PATH] = ACPI_TYPE_STRING,
+	[IS_READONLY] = ACPI_TYPE_INTEGER,
+	[DISPLAY_IN_UI] = ACPI_TYPE_INTEGER,
+	[REQUIRES_PHYSICAL_PRESENCE] = ACPI_TYPE_INTEGER,
+	[SEQUENCE] = ACPI_TYPE_INTEGER,
+	[PREREQUISITES_SIZE] = ACPI_TYPE_INTEGER,
+	[PREREQUISITES] = ACPI_TYPE_STRING,
+	[SECURITY_LEVEL] = ACPI_TYPE_INTEGER,
+	[INT_LOWER_BOUND] = ACPI_TYPE_INTEGER,
+	[INT_UPPER_BOUND] = ACPI_TYPE_INTEGER,
+	[INT_SCALAR_INCREMENT] = ACPI_TYPE_INTEGER,
+};
+
+static int hp_populate_integer_elements_from_package(union acpi_object *integer_obj,
+						     int integer_obj_count,
+						     int instance_id)
+{
+	char *str_value = NULL;
+	int value_len;
+	int ret;
+	u32 int_value;
+	int elem;
+	int reqs;
+	int eloc;
+	int size;
+	struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
+
+	if (!integer_obj)
+		return -EINVAL;
+
+	for (elem = 1, eloc = 1; elem < integer_obj_count; elem++, eloc++) {
+		/* ONLY look at the first INTEGER_ELEM_CNT elements */
+		if (eloc == INT_ELEM_CNT)
+			goto exit_integer_package;
+
+		switch (integer_obj[elem].type) {
+		case ACPI_TYPE_STRING:
+			if (elem != PREREQUISITES) {
+				ret = hp_convert_hexstr_to_str(integer_obj[elem].string.pointer,
+							       integer_obj[elem].string.length,
+							       &str_value, &value_len);
+				if (ret)
+					continue;
+			}
+			break;
+		case ACPI_TYPE_INTEGER:
+			int_value = (u32)integer_obj[elem].integer.value;
+			break;
+		default:
+			pr_warn("Unsupported object type [%d]\n", integer_obj[elem].type);
+			continue;
+		}
+		/* Check that both expected and read object type match */
+		if (expected_integer_types[eloc] != integer_obj[elem].type) {
+			pr_err("Error expected type %d for elem %d, but got type %d instead\n",
+			       expected_integer_types[eloc], elem, integer_obj[elem].type);
+			return -EIO;
+		}
+		/* Assign appropriate element value to corresponding field*/
+		switch (eloc) {
+		case VALUE:
+			ret = kstrtoint(str_value, 10, &int_value);
+			if (ret)
+				continue;
+
+			integer_data->current_value = int_value;
+			break;
+		case PATH:
+			strscpy(integer_data->common.path, str_value,
+				sizeof(integer_data->common.path));
+			break;
+		case IS_READONLY:
+			integer_data->common.is_readonly = int_value;
+			break;
+		case DISPLAY_IN_UI:
+			integer_data->common.display_in_ui = int_value;
+			break;
+		case REQUIRES_PHYSICAL_PRESENCE:
+			integer_data->common.requires_physical_presence = int_value;
+			break;
+		case SEQUENCE:
+			integer_data->common.sequence = int_value;
+			break;
+		case PREREQUISITES_SIZE:
+			if (integer_data->common.prerequisites_size > MAX_PREREQUISITES_SIZE)
+				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
+			/*
+			 * This HACK is needed to keep the expected
+			 * element list pointing to the right obj[elem].type
+			 * when the size is zero. PREREQUISITES
+			 * object is omitted by BIOS when the size is
+			 * zero.
+			 */
+			if (integer_data->common.prerequisites_size == 0)
+				eloc++;
+			break;
+		case PREREQUISITES:
+			size = min_t(u32, integer_data->common.prerequisites_size, MAX_PREREQUISITES_SIZE);
+
+			for (reqs = 0; reqs < size; reqs++) {
+				if (elem >= integer_obj_count) {
+					pr_err("Error elem-objects package is too small\n");
+					return -EINVAL;
+				}
+
+				ret = hp_convert_hexstr_to_str(integer_obj[elem + reqs].string.pointer,
+							       integer_obj[elem + reqs].string.length,
+							       &str_value, &value_len);
+
+				if (ret)
+					continue;
+
+				strscpy(integer_data->common.prerequisites[reqs],
+					str_value,
+					sizeof(integer_data->common.prerequisites[reqs]));
+				kfree(str_value);
+			}
+			break;
+
+		case SECURITY_LEVEL:
+			integer_data->common.security_level = int_value;
+			break;
+		case INT_LOWER_BOUND:
+			integer_data->lower_bound = int_value;
+			break;
+		case INT_UPPER_BOUND:
+			integer_data->upper_bound = int_value;
+			break;
+		case INT_SCALAR_INCREMENT:
+			integer_data->scalar_increment = int_value;
+			break;
+		default:
+			pr_warn("Invalid element: %d found in Integer attribute or data may be malformed\n", elem);
+			break;
+		}
+	}
+exit_integer_package:
+	kfree(str_value);
+	return 0;
+}
+
+/**
+ * hp_populate_integer_package_data() -
+ * Populate all properties of an instance under integer attribute
+ *
+ * @integer_obj: ACPI object with integer data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int hp_populate_integer_package_data(union acpi_object *integer_obj,
+				     int instance_id,
+				     struct kobject *attr_name_kobj)
+{
+	struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
+
+	integer_data->attr_name_kobj = attr_name_kobj;
+	hp_populate_integer_elements_from_package(integer_obj,
+						  integer_obj->package.count,
+						  instance_id);
+	hp_update_attribute_permissions(integer_data->common.is_readonly,
+					&integer_current_val);
+	hp_friendly_user_name_update(integer_data->common.path,
+				     attr_name_kobj->name,
+				     integer_data->common.display_name,
+				     sizeof(integer_data->common.display_name));
+	return sysfs_create_group(attr_name_kobj, &integer_attr_group);
+}
+
+static int hp_populate_integer_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
+						    int instance_id)
+{
+	char *dst = NULL;
+	int dst_size = *buffer_size / sizeof(u16);
+	struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
+	int ret = 0;
+
+	dst = kcalloc(dst_size, sizeof(char), GFP_KERNEL);
+	if (!dst)
+		return -ENOMEM;
+
+	/*
+	 * Only data relevant to this driver and its functionality is
+	 * read. BIOS defines the order in which each * element is
+	 * read. Element 0 data is not relevant to this
+	 * driver hence it is ignored. For clarity, all element names
+	 * (DISPLAY_IN_UI) which defines the order in which is read
+	 * and the name matches the variable where the data is stored.
+	 *
+	 * In earlier implementation, reported errors were ignored
+	 * causing the data to remain uninitialized. It is not
+	 * possible to determine if data read from BIOS is valid or
+	 * not. It is for this reason functions may return a error
+	 * without validating the data itself.
+	 */
+
+	// VALUE:
+	integer_data->current_value = 0;
+
+	hp_get_string_from_buffer(&buffer_ptr, buffer_size, dst, dst_size);
+	ret = kstrtoint(dst, 10, &integer_data->current_value);
+	if (ret)
+		pr_warn("Unable to convert string to integer: %s\n", dst);
+	kfree(dst);
+
+	// COMMON:
+	ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size, &integer_data->common);
+	if (ret < 0)
+		goto buffer_exit;
+
+	// INT_LOWER_BOUND:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+					 &integer_data->lower_bound);
+	if (ret < 0)
+		goto buffer_exit;
+
+	// INT_UPPER_BOUND:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+					 &integer_data->upper_bound);
+	if (ret < 0)
+		goto buffer_exit;
+
+	// INT_SCALAR_INCREMENT:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+					 &integer_data->scalar_increment);
+
+buffer_exit:
+	return ret;
+}
+
+/**
+ * hp_populate_integer_buffer_data() -
+ * Populate all properties of an instance under integer attribute
+ *
+ * @buffer_ptr: Buffer pointer
+ * @buffer_size: Buffer size
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int hp_populate_integer_buffer_data(u8 *buffer_ptr, u32 *buffer_size, int instance_id,
+				    struct kobject *attr_name_kobj)
+{
+	struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
+	int ret = 0;
+
+	integer_data->attr_name_kobj = attr_name_kobj;
+
+	/* Populate integer elements */
+	ret = hp_populate_integer_elements_from_buffer(buffer_ptr, buffer_size,
+						       instance_id);
+	if (ret < 0)
+		return ret;
+
+	hp_update_attribute_permissions(integer_data->common.is_readonly,
+					&integer_current_val);
+	hp_friendly_user_name_update(integer_data->common.path,
+				     attr_name_kobj->name,
+				     integer_data->common.display_name,
+				     sizeof(integer_data->common.display_name));
+
+	return sysfs_create_group(attr_name_kobj, &integer_attr_group);
+}
+
+/**
+ * hp_exit_integer_attributes() - Clear all attribute data
+ *
+ * Clears all data allocated for this group of attributes
+ */
+void hp_exit_integer_attributes(void)
+{
+	int instance_id;
+
+	for (instance_id = 0; instance_id < bioscfg_drv.integer_instances_count;
+	     instance_id++) {
+		struct kobject *attr_name_kobj =
+			bioscfg_drv.integer_data[instance_id].attr_name_kobj;
+
+		if (attr_name_kobj)
+			sysfs_remove_group(attr_name_kobj, &integer_attr_group);
+	}
+	bioscfg_drv.integer_instances_count = 0;
+
+	kfree(bioscfg_drv.integer_data);
+	bioscfg_drv.integer_data = NULL;
+}