Add string 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@xxxxxx>
---
Based on the latest platform-drivers-x86.git/for-next
---
.../x86/hp/hp-bioscfg/string-attributes.c | 390 ++++++++++++++++++
1 file changed, 390 insertions(+)
create mode 100644 drivers/platform/x86/hp/hp-bioscfg/string-attributes.c
diff --git a/drivers/platform/x86/hp/hp-bioscfg/string-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/string-attributes.c
new file mode 100644
index 000000000000..1b62e372fb9e
--- /dev/null
+++ b/drivers/platform/x86/hp/hp-bioscfg/string-attributes.c
@@ -0,0 +1,390 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to string type attributes under
+ * HP_WMI_BIOS_STRING_GUID for use with hp-bioscfg driver.
+ *
+ * Copyright (c) 2022 HP Development Company, L.P.
+ */
+
+#include "bioscfg.h"
+
+#define WMI_STRING_TYPE "HPBIOS_BIOSString"
+
+GET_INSTANCE_ID(string);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ int instance_id = get_string_instance_id(kobj);
+
+ if (instance_id < 0)
+ return -EIO;
+
+ return sysfs_emit(buf, "%s\n",
+ bioscfg_drv.string_data[instance_id].current_value);
+}
+
+/**
+ * validate_string_input() -
+ * Validate input of current_value against min and max lengths
+ *
+ * @instance_id: The instance on which input is validated
+ * @buf: Input value
+ */
+static int validate_string_input(int instance_id, const char *buf)
+{
+ int in_len = strlen(buf);
+ struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
+
+ /* BIOS treats it as a read only attribute */
+ if (string_data->common.is_readonly)
+ return -EIO;
+
+ if (in_len < string_data->min_length || in_len > string_data->max_length)
+ return -ERANGE;
+
+ return 0;
+}
+
+static void update_string_value(int instance_id, char *attr_value)
+{
+ struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
+
+ /* Write settings to BIOS */
+ strscpy(string_data->current_value, attr_value, sizeof(string_data->current_value));
+}
+
+/*
+ * ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name_language_code, string);
+ * static struct kobj_attribute string_display_langcode =
+ * __ATTR_RO(display_name_language_code);
+ */
+
+ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, string);
+static struct kobj_attribute string_display_name =
+ __ATTR_RO(display_name);
+
+ATTRIBUTE_PROPERTY_STORE(current_value, string);
+static struct kobj_attribute string_current_val =
+ __ATTR_RW_MODE(current_value, 0644);
+
+ATTRIBUTE_N_PROPERTY_SHOW(min_length, string);
+static struct kobj_attribute string_min_length =
+ __ATTR_RO(min_length);
+
+ATTRIBUTE_N_PROPERTY_SHOW(max_length, string);
+static struct kobj_attribute string_max_length =
+ __ATTR_RO(max_length);
+
+static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "string\n");
+}
+
+static struct kobj_attribute string_type =
+ __ATTR_RO(type);
+
+static struct attribute *string_attrs[] = {
+ &common_display_langcode.attr,
+ &string_display_name.attr,
+ &string_current_val.attr,
+ &string_min_length.attr,
+ &string_max_length.attr,
+ &string_type.attr,
+ NULL
+};
+
+static const struct attribute_group string_attr_group = {
+ .attrs = string_attrs,
+};
+
+int hp_alloc_string_data(void)
+{
+ bioscfg_drv.string_instances_count = hp_get_instance_count(HP_WMI_BIOS_STRING_GUID);
+ bioscfg_drv.string_data = kcalloc(bioscfg_drv.string_instances_count,
+ sizeof(*bioscfg_drv.string_data), GFP_KERNEL);
+ if (!bioscfg_drv.string_data) {
+ bioscfg_drv.string_instances_count = 0;
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+/* Expected Values types associated with each element */
+static const acpi_object_type expected_string_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,
+ [STR_MIN_LENGTH] = ACPI_TYPE_INTEGER,
+ [STR_MAX_LENGTH] = ACPI_TYPE_INTEGER,
+};
+
+static int hp_populate_string_elements_from_package(union acpi_object *string_obj,
+ int string_obj_count,
+ int instance_id)
+{
+ char *str_value = NULL;
+ int value_len;
+ int ret = 0;
+ u32 int_value;
+ int elem;
+ int reqs;
+ int eloc;
+ int size;
+ struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
+
+ if (!string_obj)
+ return -EINVAL;
+
+ for (elem = 1, eloc = 1; elem < string_obj_count; elem++, eloc++) {
+ /* ONLY look at the first STRING_ELEM_CNT elements */
+ if (eloc == STR_ELEM_CNT)
+ goto exit_string_package;
+
+ switch (string_obj[elem].type) {
+ case ACPI_TYPE_STRING:
+ if (elem != PREREQUISITES) {
+ ret = hp_convert_hexstr_to_str(string_obj[elem].string.pointer,
+ string_obj[elem].string.length,
+ &str_value, &value_len);
+
+ if (ret)
+ continue;
+ }
+ break;
+ case ACPI_TYPE_INTEGER:
+ int_value = (u32)string_obj[elem].integer.value;
+ break;
+ default:
+ pr_warn("Unsupported object type [%d]\n", string_obj[elem].type);
+ continue;
+ }
+
+ /* Check that both expected and read object type match */
+ if (expected_string_types[eloc] != string_obj[elem].type) {
+ pr_err("Error expected type %d for elem %d, but got type %d instead\n",
+ expected_string_types[eloc], elem, string_obj[elem].type);
+ return -EIO;
+ }
+
+ /* Assign appropriate element value to corresponding field*/
+ switch (eloc) {
+ case VALUE:
+ strscpy(string_data->current_value,
+ str_value, sizeof(string_data->current_value));
+ break;
+ case PATH:
+ strscpy(string_data->common.path, str_value,
+ sizeof(string_data->common.path));
+ break;
+ case IS_READONLY:
+ string_data->common.is_readonly = int_value;
+ break;
+ case DISPLAY_IN_UI:
+ string_data->common.display_in_ui = int_value;
+ break;
+ case REQUIRES_PHYSICAL_PRESENCE:
+ string_data->common.requires_physical_presence = int_value;
+ break;
+ case SEQUENCE:
+ string_data->common.sequence = int_value;
+ break;
+ case PREREQUISITES_SIZE:
+ string_data->common.prerequisites_size = int_value;
+
+ if (string_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 (string_data->common.prerequisites_size == 0)
+ eloc++;
+ break;
+ case PREREQUISITES:
+ size = min_t(u32, string_data->common.prerequisites_size,
+ MAX_PREREQUISITES_SIZE);
+
+ for (reqs = 0; reqs < size; reqs++) {
+ if (elem >= string_obj_count) {
+ pr_err("Error elem-objects package is too small\n");
+ return -EINVAL;
+ }
+
+ ret = hp_convert_hexstr_to_str(string_obj[elem + reqs].string.pointer,
+ string_obj[elem + reqs].string.length,
+ &str_value, &value_len);
+
+ if (ret)
+ continue;
+
+ strscpy(string_data->common.prerequisites[reqs],
+ str_value,
+ sizeof(string_data->common.prerequisites[reqs]));
+ kfree(str_value);
+ }
+ break;
+
+ case SECURITY_LEVEL:
+ string_data->common.security_level = int_value;
+ break;
+ case STR_MIN_LENGTH:
+ string_data->min_length = int_value;
+ break;
+ case STR_MAX_LENGTH:
+ string_data->max_length = int_value;
+ break;
+ default:
+ pr_warn("Invalid element: %d found in String attribute or data may be malformed\n", elem);
+ break;
+ }
+
+ kfree(str_value);
+ }
+
+exit_string_package:
+ kfree(str_value);
+ return 0;
+}
+
+/**
+ * hp_populate_string_package_data() -
+ * Populate all properties of an instance under string attribute
+ *
+ * @string_obj: ACPI object with string data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int hp_populate_string_package_data(union acpi_object *string_obj,
+ int instance_id,
+ struct kobject *attr_name_kobj)
+{
+ struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
+
+ string_data->attr_name_kobj = attr_name_kobj;
+
+ hp_populate_string_elements_from_package(string_obj,
+ string_obj->package.count,
+ instance_id);
+
+ hp_update_attribute_permissions(string_data->common.is_readonly,
+ &string_current_val);
+ hp_friendly_user_name_update(string_data->common.path,
+ attr_name_kobj->name,
+ string_data->common.display_name,
+ sizeof(string_data->common.display_name));
+ return sysfs_create_group(attr_name_kobj, &string_attr_group);
+}
+
+static int hp_populate_string_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
+ int instance_id)
+{
+ int ret = 0;
+ struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
+
+ /*
+ * 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:
+ ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size, string_data->current_value,
+ sizeof(string_data->current_value));
+ if (ret < 0)
+ goto buffer_exit;
+
+ // COMMON:
+ ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size, &string_data->common);
+ if (ret < 0)
+ goto buffer_exit;
+
+ // STR_MIN_LENGTH:
+ ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+ &string_data->min_length);
+ if (ret < 0)
+ goto buffer_exit;
+
+ // STR_MAX_LENGTH:
+ ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+ &string_data->max_length);
+
+buffer_exit:
+
+ return ret;
+}
+
+/**
+ * hp_populate_string_buffer_data() -
+ * Populate all properties of an instance under string 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_string_buffer_data(u8 *buffer_ptr, u32 *buffer_size,
+ int instance_id,
+ struct kobject *attr_name_kobj)
+{
+ struct string_data *string_data = &bioscfg_drv.string_data[instance_id];
+ int ret = 0;
+
+ string_data->attr_name_kobj = attr_name_kobj;
+
+ ret = hp_populate_string_elements_from_buffer(buffer_ptr, buffer_size,
+ instance_id);
+ if (ret < 0)
+ return ret;
+
+ hp_update_attribute_permissions(string_data->common.is_readonly,
+ &string_current_val);
+ hp_friendly_user_name_update(string_data->common.path,
+ attr_name_kobj->name,
+ string_data->common.display_name,
+ sizeof(string_data->common.display_name));
+
+ return sysfs_create_group(attr_name_kobj, &string_attr_group);
+}
+
+/**
+ * hp_exit_string_attributes() - Clear all attribute data
+ *
+ * Clears all data allocated for this group of attributes
+ */
+void hp_exit_string_attributes(void)
+{
+ int instance_id;
+
+ for (instance_id = 0; instance_id < bioscfg_drv.string_instances_count;
+ instance_id++) {
+ struct kobject *attr_name_kobj =
+ bioscfg_drv.string_data[instance_id].attr_name_kobj;
+
+ if (attr_name_kobj)
+ sysfs_remove_group(attr_name_kobj, &string_attr_group);
+ }
+ bioscfg_drv.string_instances_count = 0;
+
+ kfree(bioscfg_drv.string_data);
+ bioscfg_drv.string_data = NULL;
+}
--
2.34.1
