[v2] Introduce support for Systems Management Driver over WMI for Dell Systems

Commit Message

Divya Bharathi Sept. 4, 2020, 2:28 p.m. UTC

The Dell WMI Systems Management Driver provides a sysfs
interface for systems management to enable BIOS configuration
capability on certain Dell Systems.

This driver allows user to configure Dell systems with a
uniform common interface. To facilitate this, the patch
introduces a generic way for driver to be able to create
configurable BIOS Attributes available in Setup (F2) screen.

Cc: Hans de Goede <[e-mail]>
Cc: Andy Shevchenko <[e-mail]>

Co-developed-by: Mario Limonciello <[e-mail]>
Signed-off-by: Mario Limonciello <[e-mail]>
Co-developed-by: Prasanth KSR <[e-mail]>
Signed-off-by: Prasanth KSR <[e-mail]>
Signed-off-by: Divya Bharathi <[e-mail]>
---

ChangeLog from v1 to v2:
 - use pr_fmt instead of pr_err(DRIVER_NAME
 - re-order variables reverse xmas tree order
 - correct returns of -1 to error codes
 - correct usage of {} on some split line statements
 - Refine all documentation deficiencies suggested by Hans
 - Merge all attributes to a single directory
 - Overhaul WMI interface interaction as suggested by Hans
   * Move WMI driver registration to start of module
   * Remove usage of lists that only use first entry for WMI interfaces
   * Create a global structure shared across interface source files
   * Make get_current_password function static
   * Remove get_pending changes function, shared across global structure now.
- Overhaul use of mutexes
   * Make kset list mutex shared across source files
   * Remove unneeded dell-wmi-sysman call_mutex
   * Keep remaining call_mutexes in WMI functions
- Move security area calculation into a function
- Use NLS helper for utf8->utf16 conversion

 .../testing/sysfs-platform-dell-wmi-sysman    | 126 ++++
 MAINTAINERS                                   |   9 +
 drivers/platform/x86/Kconfig                  |  12 +
 drivers/platform/x86/Makefile                 |   8 +
 .../x86/dell-wmi-biosattr-interface.c         | 198 ++++++
 .../platform/x86/dell-wmi-enum-attributes.c   | 214 +++++++
 .../platform/x86/dell-wmi-int-attributes.c    | 195 ++++++
 .../x86/dell-wmi-passobj-attributes.c         | 168 +++++
 .../x86/dell-wmi-passwordattr-interface.c     | 200 ++++++
 .../platform/x86/dell-wmi-string-attributes.c | 177 ++++++
 .../platform/x86/dell-wmi-sysman-attributes.c | 572 ++++++++++++++++++
 .../platform/x86/dell-wmi-sysman-attributes.h | 132 ++++
 12 files changed, 2011 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
 create mode 100644 drivers/platform/x86/dell-wmi-biosattr-interface.c
 create mode 100644 drivers/platform/x86/dell-wmi-enum-attributes.c
 create mode 100644 drivers/platform/x86/dell-wmi-int-attributes.c
 create mode 100644 drivers/platform/x86/dell-wmi-passobj-attributes.c
 create mode 100644 drivers/platform/x86/dell-wmi-passwordattr-interface.c
 create mode 100644 drivers/platform/x86/dell-wmi-string-attributes.c
 create mode 100644 drivers/platform/x86/dell-wmi-sysman-attributes.c
 create mode 100644 drivers/platform/x86/dell-wmi-sysman-attributes.h

Comments

mark gross Sept. 11, 2020, 6:31 p.m. UTC | #1

On Fri, Sep 04, 2020 at 07:58:46PM +0530, Divya Bharathi wrote:
> The Dell WMI Systems Management Driver provides a sysfs
> interface for systems management to enable BIOS configuration
> capability on certain Dell Systems.
> 
> This driver allows user to configure Dell systems with a
> uniform common interface. To facilitate this, the patch
> introduces a generic way for driver to be able to create
> configurable BIOS Attributes available in Setup (F2) screen.
> 
> Cc: Hans de Goede <[e-mail]>
> Cc: Andy Shevchenko <[e-mail]>
> 
> Co-developed-by: Mario Limonciello <[e-mail]>
> Signed-off-by: Mario Limonciello <[e-mail]>
> Co-developed-by: Prasanth KSR <[e-mail]>
> Signed-off-by: Prasanth KSR <[e-mail]>
> Signed-off-by: Divya Bharathi <[e-mail]>
> ---
> 
> ChangeLog from v1 to v2:
>  - use pr_fmt instead of pr_err(DRIVER_NAME
>  - re-order variables reverse xmas tree order
>  - correct returns of -1 to error codes
>  - correct usage of {} on some split line statements
>  - Refine all documentation deficiencies suggested by Hans
>  - Merge all attributes to a single directory
>  - Overhaul WMI interface interaction as suggested by Hans
>    * Move WMI driver registration to start of module
>    * Remove usage of lists that only use first entry for WMI interfaces
>    * Create a global structure shared across interface source files
>    * Make get_current_password function static
>    * Remove get_pending changes function, shared across global structure now.
> - Overhaul use of mutexes
>    * Make kset list mutex shared across source files
>    * Remove unneeded dell-wmi-sysman call_mutex
>    * Keep remaining call_mutexes in WMI functions
> - Move security area calculation into a function
> - Use NLS helper for utf8->utf16 conversion
> 
>  .../testing/sysfs-platform-dell-wmi-sysman    | 126 ++++
>  MAINTAINERS                                   |   9 +
>  drivers/platform/x86/Kconfig                  |  12 +
>  drivers/platform/x86/Makefile                 |   8 +
>  .../x86/dell-wmi-biosattr-interface.c         | 198 ++++++
>  .../platform/x86/dell-wmi-enum-attributes.c   | 214 +++++++
>  .../platform/x86/dell-wmi-int-attributes.c    | 195 ++++++
>  .../x86/dell-wmi-passobj-attributes.c         | 168 +++++
>  .../x86/dell-wmi-passwordattr-interface.c     | 200 ++++++
>  .../platform/x86/dell-wmi-string-attributes.c | 177 ++++++
>  .../platform/x86/dell-wmi-sysman-attributes.c | 572 ++++++++++++++++++
>  .../platform/x86/dell-wmi-sysman-attributes.h | 132 ++++
>  12 files changed, 2011 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
>  create mode 100644 drivers/platform/x86/dell-wmi-biosattr-interface.c
>  create mode 100644 drivers/platform/x86/dell-wmi-enum-attributes.c
>  create mode 100644 drivers/platform/x86/dell-wmi-int-attributes.c
>  create mode 100644 drivers/platform/x86/dell-wmi-passobj-attributes.c
>  create mode 100644 drivers/platform/x86/dell-wmi-passwordattr-interface.c
>  create mode 100644 drivers/platform/x86/dell-wmi-string-attributes.c
>  create mode 100644 drivers/platform/x86/dell-wmi-sysman-attributes.c
>  create mode 100644 drivers/platform/x86/dell-wmi-sysman-attributes.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman b/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
> new file mode 100644
> index 000000000000..e4b608275ea4
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
> @@ -0,0 +1,126 @@
> +What:		/sys/devices/platform/dell-wmi-sysman/attributes/
> +Date:		December 2020
> +KernelVersion:	5.10
> +Contact:	Divya Bharathi <[e-mail]>,
> +		Mario Limonciello <[e-mail]>,
> +		Prasanth KSR <[e-mail]>
> +Description:
> +		The Dell WMI Systems Management Driver provides a sysfs interface
> +		for systems management software to enable BIOS configuration
> +		capability on certain Dell systems. This directory exposes
> +		interfaces for interacting with BIOS attributes.
> +
> +		Attributes can accept a set of pre-defined valid values or a range of
> +		numerical values or a string. An atribute can accept float as well,
> +		if so '.' is used as decimal separator.
> +
> +		Also, BIOS Admin password and System Password can be set, reset or
> +		cleared using these attributes. An "Admin" password is used for
> +		preventing modification to the BIOS settings. A "System" password is
> +		required to boot a machine.
> +
> +		current_value:	A file that can be read to obtain the current
> +		value of the <attr>
> +
> +		This file can also be written to in order to update
> +		the value of a <attr>
> +
> +		default_value:	A file that can be read to obtain the default
> +		value of the <attr>
> +
> +		display_name:	A file that can be read to obtain a user friendly
> +		description of the at <attr>
> +
> +		display_name_language_code:	A file that can be read to obtain
> +		the IETF language tag corresponding to the "display_name" of the <attr>
> +
> +		modifier:	A file that can be read to obtain attribute-level
> +		dependency rule. It says an attribute X will become read-only or
> +		suppressed,	if attribute Y is not configured.
> +		For example, AutoOnHr becomes read-only if AutoOn is disabled
> +
> +		possible_value:	A file that can be read to obtain the possible
> +		values of the <attr>. Values are separated using semi-colon.
> +
> +		value_modifier:	A file that can be read to obtain value-level
> +		dependency. This file is similar to modifier but here, an attribute's
> +		current value will be forcefully changed based dependent attributes
> +		value.
> +		For example, current value of LegacyOrom will become Disabled if
> +		SecureBoot is Enabled.
> +
> +		lower_bound:	A file that can be read to obtain the lower
> +		bound value of the <attr>
> +
> +		upper_bound:	A file that can be read to obtain the upper
> +		bound value of the <attr>
> +
> +		scalar_increment:	A file that can be read to obtain the
> +		resolution of the incremental value this attribute accepts.
> +
> +		max_length:	A file that can be read to obtain the maximum
> +		length value of the <attr>
> +
> +		min_length:	A file that can be read to obtain the minimum
> +		length value of the <attr>
> +
> +		is_password_set:	A file that can be read
> +		to obtain flag to see if a password is set on <attr>
> +
> +		max_password_length:	A file that can be read to obtain the
> +		maximum length of the Password
> +
> +		min_password_length:	A file that can be read to obtain the
> +		minimum length of the Password
> +
> +		current_password: A write only value used for privileged access
> +		such as setting attributes when a system or admin password is set
> +		or resetting to a new password
> +
> +		new_password: A write only value that when used in tandem with
> +		current_password will reset a system or admin password.
> +
> +What:		/sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
> +Date:		December 2020
> +KernelVersion:	5.10
> +Contact:	Divya Bharathi <[e-mail]>,
> +		Mario Limonciello <[e-mail]>,
> +		Prasanth KSR <[e-mail]>
> +Description:
> +		This attribute can be used to reset the BIOS Configuration.
> +		Specifically, it tells which type of reset BIOS configuration is being
> +		requested on the host.
> +
> +		Reading from it returns a list of supported options encoded as:
> +
> +			'builtinsafe' (Built in safe configuration profile)
> +			'lastknowngood' (Last known good saved configuration profile)
> +			'factory' (Default factory settings configuration profile)
> +			'custom' (Custom saved configuration profile)
> +
> +		The currently selected option is printed in square brackets as
> +		shown below:
> +
> +		# echo "factory" > sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
> +
> +		# cat sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
> +		# builtinsafe lastknowngood [factory] custom
> +
> +		Note that any changes to this attribute requires a reboot
> +		for changes to take effect.
> +
> +What:		/sys/devices/platform/dell-wmi-sysman/attributes/pending_reboot
> +Date:		December 2020
> +KernelVersion:	5.10
> +Contact:	Divya Bharathi <[e-mail]>,
> +		Mario Limonciello <[e-mail]>,
> +		Prasanth KSR <[e-mail]>
> +Description:
> +		A read-only attribute reads 1 if a reboot is necessary to apply
> +		pending BIOS attribute changes.
> +
> +			0:	All BIOS attributes setting are current
> +			1:	A reboot is necessary to get pending BIOS attribute changes
> +				applied
> +
> +
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 592467ba3f4d..36ca5671a62d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4940,6 +4940,15 @@ M:	Mario Limonciello <[e-mail]>
>  S:	Maintained
>  F:	drivers/platform/x86/dell-wmi-descriptor.c
>  
> +DELL WMI SYSMAN DRIVER
> +M:	Divya Bharathi <[e-mail]>
> +M:	Mario Limonciello <[e-mail]>
> +M:	Prasanth Ksr <[e-mail]>
> +L:	[e-mail]
> +S:	Maintained
> +F:	drivers/platform/x86/dell-wmi-*-attributes.*
> +F:	drivers/platform/x86/dell-wmi-*-interface.c
> +
>  DELL WMI NOTIFICATIONS DRIVER
>  M:	Matthew Garrett <[e-mail]>
>  M:	Pali Rohár <[e-mail]>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 40219bba6801..80646b328d72 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -430,6 +430,18 @@ config DELL_WMI
>  	  To compile this driver as a module, choose M here: the module will
>  	  be called dell-wmi.
>  
> +config DELL_WMI_SYSMAN
> +	tristate "Dell WMI SYSMAN"
> +	depends on ACPI_WMI
> +	depends on DMI
> +	select NLS
> +	help
> +	  This driver allows changing BIOS settings on many Dell machines from
> +	  2018 and newer without the use of any additional software.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called dell-wmi-sysman.
> +
>  config DELL_WMI_DESCRIPTOR
>  	tristate
>  	depends on ACPI_WMI
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 5f823f7eff45..dc2ccb574192 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -47,6 +47,14 @@ obj-$(CONFIG_DELL_WMI)			+= dell-wmi.o
>  obj-$(CONFIG_DELL_WMI_DESCRIPTOR)	+= dell-wmi-descriptor.o
>  obj-$(CONFIG_DELL_WMI_AIO)		+= dell-wmi-aio.o
>  obj-$(CONFIG_DELL_WMI_LED)		+= dell-wmi-led.o
> +obj-$(CONFIG_DELL_WMI_SYSMAN)  += dell-wmi-sysman.o
> +dell-wmi-sysman-objs := dell-wmi-sysman-attributes.o \
> +				 dell-wmi-enum-attributes.o \
> +				 dell-wmi-int-attributes.o \
> +				 dell-wmi-string-attributes.o \
> +				 dell-wmi-passobj-attributes.o \
> +				 dell-wmi-passwordattr-interface.o \
> +				 dell-wmi-biosattr-interface.o
>  
>  # Fujitsu
>  obj-$(CONFIG_AMILO_RFKILL)	+= amilo-rfkill.o
> diff --git a/drivers/platform/x86/dell-wmi-biosattr-interface.c b/drivers/platform/x86/dell-wmi-biosattr-interface.c
> new file mode 100644
> index 000000000000..dda38d448fec
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-biosattr-interface.c
> @@ -0,0 +1,198 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to SET methods under BIOS attributes interface GUID for use
> + * with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include <linux/nls.h>
> +#include <linux/wmi.h>
> +#include "dell-wmi-sysman-attributes.h"
> +
> +#define SETDEFAULTVALUES_METHOD_ID					0x02
> +#define SETBIOSDEFAULTS_METHOD_ID					0x03
> +#define SETATTRIBUTE_METHOD_ID						0x04
> +
> +static DEFINE_MUTEX(call_mutex);
> +
> +extern struct dell_wmi_sysman_priv wmi_priv;
> +
> +static int call_biosattributes_interface(struct wmi_device *wdev, char *in_args, size_t size,
> +					int method_id)
> +{
> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_buffer input;
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int ret = -EIO;
> +
> +	input.length =  (acpi_size) size;
> +	input.pointer = in_args;
> +	status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +	obj = (union acpi_object *)output.pointer;
> +	if (obj->type == ACPI_TYPE_INTEGER)
> +		ret = obj->integer.value;
> +
> +	kfree(output.pointer);
> +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
> +	return map_wmi_error(ret);
> +}
> +
> +/**
> + * set_attribute() - Update an attribute value
> + * @a_name: The attribute name
> + * @a_value: The attribute value
> + *
> + * Sets an attribute to new value
> + **/
> +int set_attribute(const char *a_name, const char *a_value)
> +{
> +	size_t security_area_size, string_area_size, buffer_size;
> +	char *attribute_name, *attribute_value;
> +	u8 *name_len, *value_len;
> +	char *buffer;
> +	int ret;
> +
> +	/* build/calculate buffer */
> +	security_area_size = calculate_security_buffer();
> +	string_area_size = (strlen(a_name) + strlen(a_value))*2;
> +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 2;
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	/* build security area */
> +	if (strlen(wmi_priv.current_admin_password) > 0)
> +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
> +
> +	/* build variables to set */
> +	name_len = buffer + security_area_size;
> +	attribute_name = name_len + sizeof(u16);
> +	*name_len = utf8s_to_utf16s(a_name, strlen(a_name), UTF16_HOST_ENDIAN,
> +				    (wchar_t *) attribute_name, MAX_BUFF) * 2;
> +	if (*name_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_set_attribute;
> +	}
> +
> +	value_len = (u8 *) attribute_name + *name_len;
> +	attribute_value = value_len + sizeof(u16);
> +	*value_len = utf8s_to_utf16s(a_value, strlen(a_value), UTF16_HOST_ENDIAN,
> +				    (wchar_t *) attribute_value, MAX_BUFF) * 2;
> +	if (*value_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_set_attribute;
> +	}
> +
> +	mutex_lock(&call_mutex);
> +	if (!wmi_priv.bios_attr_wdev) {
> +		ret = -ENODEV;
> +		pr_err("no WMI backend bound");
> +		goto out_set_attribute;
> +	}
> +
> +	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
> +					    buffer, buffer_size,
> +					    SETATTRIBUTE_METHOD_ID);
> +	if (ret == -EOPNOTSUPP)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured");
> +	else if (ret == -EACCES)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
> +
> +	wmi_priv.pending_changes = 1;
> +out_set_attribute:
> +	kfree(buffer);
> +	mutex_unlock(&call_mutex);
> +
> +	return ret;
> +}
> +
> +/**
> + * set_bios_defaults() - Resets BIOS defaults
> + * @deftype: the type of BIOS value reset to issue.
> + *
> + * Resets BIOS defaults
> + **/
> +int set_bios_defaults(u8 deftype)
> +{
> +	size_t security_area_size, buffer_size;
> +	size_t integer_area_size = sizeof(u8);
> +	u8 *defaultType;
> +	char *buffer;
> +	int ret;
> +
> +	security_area_size = calculate_security_buffer();
> +	buffer_size = security_area_size + integer_area_size;
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	/* build security area */
> +	if (strlen(wmi_priv.current_admin_password) > 0)
> +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
> +
> +	mutex_lock(&call_mutex);
> +	if (!wmi_priv.bios_attr_wdev) {
> +		ret = -ENODEV;
> +		pr_err("no WMI backend bound");
> +		goto out_bios_defaults;
> +	}
> +
> +	defaultType = buffer + security_area_size;
> +	*defaultType = deftype;
> +
> +	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer, buffer_size,
> +					    SETBIOSDEFAULTS_METHOD_ID);
> +	if (ret)
> +		dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed: %d", ret);
> +	wmi_priv.pending_changes = 1;
> +out_bios_defaults:
> +	kfree(buffer);
> +	mutex_unlock(&call_mutex);
> +
> +	return ret;
> +}
> +
> +static int dell_wmi_bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
> +{
> +	wmi_priv.bios_attr_wdev = wdev;
> +	return 0;
> +}
> +
> +static int dell_wmi_bios_attr_set_interface_remove(struct wmi_device *wdev)
> +{
> +	mutex_lock(&call_mutex);
> +	wmi_priv.bios_attr_wdev = NULL;
> +	mutex_unlock(&call_mutex);
> +	return 0;
> +}
> +
> +static const struct wmi_device_id dell_wmi_bios_attr_set_interface_id_table[] = {
> +	{ .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
> +	{ },
> +};
> +static struct wmi_driver dell_wmi_bios_attr_set_interface_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME"-set"
> +	},
> +	.probe = dell_wmi_bios_attr_set_interface_probe,
> +	.remove = dell_wmi_bios_attr_set_interface_remove,
> +	.id_table = dell_wmi_bios_attr_set_interface_id_table,
> +};
> +
> +int init_dell_wmi_bios_attr_set_interface(void)
> +{
> +	return wmi_driver_register(&dell_wmi_bios_attr_set_interface_driver);
> +}
> +
> +void exit_dell_wmi_bios_attr_set_interface(void)
> +{
> +	wmi_driver_unregister(&dell_wmi_bios_attr_set_interface_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_set_interface_id_table);
> diff --git a/drivers/platform/x86/dell-wmi-enum-attributes.c b/drivers/platform/x86/dell-wmi-enum-attributes.c
> new file mode 100644
> index 000000000000..f2370f067b6d
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-enum-attributes.c
> @@ -0,0 +1,214 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to enumeration type attributes under BIOS Enumeration GUID for use
> + * with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(enum_mutex);
> +extern struct mutex kset_mutex;
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct enumeration_data {
> +	char display_name_language_code[MAX_BUFF];
> +	char attribute_name[MAX_BUFF];
> +	char display_name[MAX_BUFF];
> +	char default_value[MAX_BUFF];
> +	char current_value[MAX_BUFF];
> +	char modifier[MAX_BUFF];
> +	int value_modifier_count;
> +	char value_modifier[MAX_BUFF];
> +	int possible_value_count;
> +	char possible_value[MAX_BUFF];
> +	char type[MAX_BUFF];
> +};
> +
> +static struct enumeration_data *enumeration_data;
> +static int enumeration_instances_count;
> +get_instance_id(enumeration);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +	instance_id = get_enumeration_instance_id(kobj);
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;
> +		strncpy_attr(enumeration_data[instance_id].current_value,
> +		       obj->package.elements[CURRENT_VAL].string.pointer);
> +		kfree(obj);
> +		return sprintf(buf, "%s\n", enumeration_data[instance_id].current_value);
> +	}
> +	return -EIO;
> +}
> +
> +/**
> + * validate_enumeration_input() - Validate input of current_value against possible values
> + * @instance_id: The instance on which input is validated
> + * @buf: Input value
> + **/
> +int validate_enumeration_input(int instance_id, const char *buf)
> +{
> +	char *options, *tmp, *p;
> +	int ret = -EINVAL;
> +
> +	options = tmp = kstrdup((enumeration_data[instance_id].possible_value), GFP_KERNEL);
> +	if (!options)
> +		return -ENOMEM;
> +
> +	while ((p = strsep(&options, ";")) != NULL) {
> +		if (!*p)
> +			continue;
> +		if (!strncasecmp(p, buf, strlen(p))) {
> +			ret = 0;
> +			break;
> +		}
> +	}
> +
> +	kfree(tmp);
> +	return ret;
> +}
> +
> +attribute_s_property_show(display_name_language_code, enumeration);
> +static struct kobj_attribute displ_langcode =
> +		__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, enumeration);
> +struct kobj_attribute displ_name =
> +		__ATTR_RO(display_name);
> +
> +attribute_s_property_show(default_value, enumeration);
> +struct kobj_attribute default_val =
> +		__ATTR_RO(default_value);
> +
> +attribute_property_store(current_value, enumeration);
> +struct kobj_attribute current_val =
> +		__ATTR_RW(current_value);
> +
> +attribute_s_property_show(modifier, enumeration);
> +struct kobj_attribute modifier =
> +		__ATTR_RO(modifier);
> +
> +attribute_s_property_show(value_modifier, enumeration);
> +struct kobj_attribute value_modfr =
> +		__ATTR_RO(value_modifier);
> +
> +attribute_s_property_show(possible_value, enumeration);
> +struct kobj_attribute poss_val =
> +		__ATTR_RO(possible_value);
> +
> +attribute_s_property_show(type, enumeration);
> +struct kobj_attribute type =
> +		__ATTR_RO(type);
> +
> +static struct attribute *enumeration_attrs[] = {
> +	&displ_langcode.attr,
> +	&displ_name.attr,
> +	&default_val.attr,
> +	&current_val.attr,
> +	&modifier.attr,
> +	&value_modfr.attr,
> +	&poss_val.attr,
> +	&type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group enumeration_attr_group = {
> +	.attrs = enumeration_attrs,
> +};
> +
> +int alloc_enum_data(void)
> +{
> +	int ret = 0;
> +
> +	enumeration_instances_count = get_instance_count(DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> +	enumeration_data = kzalloc((sizeof(struct enumeration_data) * enumeration_instances_count),
> +					GFP_KERNEL);
> +	if (!enumeration_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_enum_data() - Populate all properties of an instance under enumeration attribute
> + * @enumeration_obj: ACPI object with enumeration data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + **/
> +int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
> +			struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> +	int i, next_obj;
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&enum_mutex);
> +	strncpy_attr(enumeration_data[instance_id].attribute_name,
> +		enumeration_obj[ATTR_NAME].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].display_name_language_code,
> +		enumeration_obj[DISPL_NAME_LANG_CODE].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].display_name,
> +		enumeration_obj[DISPLAY_NAME].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].default_value,
> +		enumeration_obj[DEFAULT_VAL].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].current_value,
> +		enumeration_obj[CURRENT_VAL].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].modifier,
> +		enumeration_obj[MODIFIER].string.pointer);
> +
> +	next_obj = MODIFIER + 1;
> +
> +	enumeration_data[instance_id].value_modifier_count =
> +		(uintptr_t)enumeration_obj[next_obj].string.pointer;
> +
> +	for (i = 0; i < enumeration_data[instance_id].value_modifier_count; i++) {
> +		strcat(enumeration_data[instance_id].value_modifier,
> +			enumeration_obj[++next_obj].string.pointer);
> +		strcat(enumeration_data[instance_id].value_modifier, ";");
> +	}
> +
> +	enumeration_data[instance_id].possible_value_count =
> +		(uintptr_t) enumeration_obj[++next_obj].string.pointer;
> +
> +	for (i = 0; i < enumeration_data[instance_id].possible_value_count; i++) {
> +		strcat(enumeration_data[instance_id].possible_value,
> +			enumeration_obj[++next_obj].string.pointer);
> +		strcat(enumeration_data[instance_id].possible_value, ";");
> +	}
> +	strncpy_attr(enumeration_data[instance_id].type, "enumeration");
> +	mutex_unlock(&enum_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_enum_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_enum_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &enumeration_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&enum_mutex);
> +	kfree(enumeration_data);
> +	mutex_unlock(&enum_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-int-attributes.c b/drivers/platform/x86/dell-wmi-int-attributes.c
> new file mode 100644
> index 000000000000..d922d4f73ce9
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-int-attributes.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to integer type attributes under BIOS Integer GUID for use with
> + * dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(int_mutex);
> +extern struct mutex kset_mutex;
> +
> +enum int_properties {LOWER_BOUND = 6, UPPER_BOUND, SCALAR_INCR};
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct integer_data {
> +	char display_name_language_code[MAX_BUFF];
> +	char attribute_name[MAX_BUFF];
> +	char display_name[MAX_BUFF];
> +	int default_value;
> +	int current_value;
> +	char modifier[MAX_BUFF];
> +	int lower_bound;
> +	int upper_bound;
> +	int scalar_increment;
> +	char type[MAX_BUFF];
> +};
> +
> +static struct integer_data *integer_data;
> +static int integer_instances_count;
> +get_instance_id(integer);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +	instance_id = get_integer_instance_id(kobj);
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;
> +		integer_data[instance_id].current_value =
> +			(uintptr_t)obj->package.elements[CURRENT_VAL].string.pointer;
> +		kfree(obj);
> +		return sprintf(buf, "%d\n", integer_data[instance_id].current_value);
> +	}
> +	return -EIO;
> +}
> +
> +/**
> + * 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
> + **/
> +int validate_integer_input(int instance_id, const char *buf)
> +{
> +	int ret = -EINVAL;
> +	int in_val;
> +
> +	if (kstrtoint(buf, 0, &in_val))
> +		return ret;
> +	if ((in_val >= integer_data[instance_id].lower_bound) &&
> +	(in_val <= integer_data[instance_id].upper_bound))
> +		ret = 0;
> +
> +	return ret;
> +}
> +
> +attribute_s_property_show(display_name_language_code, integer);
> +static struct kobj_attribute integer_displ_langcode =
> +	__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, integer);
> +struct kobj_attribute integer_displ_name =
> +	__ATTR_RO(display_name);
> +
> +attribute_n_property_show(default_value, integer);
> +struct kobj_attribute integer_default_val =
> +	__ATTR_RO(default_value);
> +
> +attribute_property_store(current_value, integer);
> +struct kobj_attribute integer_current_val =
> +	__ATTR_RW(current_value);
> +
> +attribute_s_property_show(modifier, integer);
> +struct kobj_attribute integer_modifier =
> +	__ATTR_RO(modifier);
> +
> +attribute_n_property_show(lower_bound, integer);
> +struct kobj_attribute integer_lower_bound =
> +	__ATTR_RO(lower_bound);
> +
> +attribute_n_property_show(upper_bound, integer);
> +struct kobj_attribute integer_upper_bound =
> +	__ATTR_RO(upper_bound);
> +
> +attribute_n_property_show(scalar_increment, integer);
> +struct kobj_attribute integer_scalar_increment =
> +	__ATTR_RO(scalar_increment);
> +
> +attribute_s_property_show(type, integer);
> +struct kobj_attribute integer_type =
> +	__ATTR_RO(type);
> +
> +static struct attribute *integer_attrs[] = {
> +	&integer_displ_langcode.attr,
> +	&integer_displ_name.attr,
> +	&integer_default_val.attr,
> +	&integer_current_val.attr,
> +	&integer_modifier.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 alloc_int_data(void)
> +{
> +	int ret = 0;
> +
> +	integer_instances_count = get_instance_count(DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> +	integer_data = kzalloc((sizeof(struct integer_data) * integer_instances_count), GFP_KERNEL);
> +	if (!integer_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_enum_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 populate_int_data(union acpi_object *integer_obj, int instance_id,
> +			struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &integer_attr_group);
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&int_mutex);
> +	strncpy_attr(integer_data[instance_id].attribute_name,
> +		integer_obj[ATTR_NAME].string.pointer);
> +	strncpy_attr(integer_data[instance_id].display_name_language_code,
> +		integer_obj[DISPL_NAME_LANG_CODE].string.pointer);
> +	strncpy_attr(integer_data[instance_id].display_name,
> +		integer_obj[DISPLAY_NAME].string.pointer);
> +	integer_data[instance_id].default_value =
> +		(uintptr_t)integer_obj[DEFAULT_VAL].string.pointer;
> +	integer_data[instance_id].current_value =
> +		(uintptr_t)integer_obj[CURRENT_VAL].string.pointer;
> +	strncpy_attr(integer_data[instance_id].modifier, integer_obj[MODIFIER].string.pointer);
> +	integer_data[instance_id].lower_bound =
> +		(uintptr_t)integer_obj[LOWER_BOUND].string.pointer;
> +	integer_data[instance_id].upper_bound =
> +		(uintptr_t)integer_obj[UPPER_BOUND].string.pointer;
> +	integer_data[instance_id].scalar_increment =
> +		(uintptr_t)integer_obj[SCALAR_INCR].string.pointer;
> +	strncpy_attr(integer_data[instance_id].type, "integer");
> +	mutex_unlock(&int_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_int_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_int_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &integer_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&int_mutex);
> +	kfree(integer_data);
> +	mutex_unlock(&int_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-passobj-attributes.c b/drivers/platform/x86/dell-wmi-passobj-attributes.c
> new file mode 100644
> index 000000000000..87bb7772bb18
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-passobj-attributes.c
> @@ -0,0 +1,168 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to password object type attributes under BIOS Password Object GUID for
> + * use with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(po_mutex);
> +extern struct mutex kset_mutex;
> +
> +enum po_properties {IS_PASS_SET = 1, MIN_PASS_LEN, MAX_PASS_LEN};
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct po_data {
> +	char attribute_name[MAX_BUFF];
> +	int is_password_set;
> +	int min_password_length;
> +	int max_password_length;
> +	char type[MAX_BUFF];
> +};
> +
> +static struct po_data *po_data;
> +static int po_instances_count;
> +get_instance_id(po);
> +
> +static ssize_t is_password_set_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id = get_po_instance_id(kobj);
> +
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;
> +		po_data[instance_id].is_password_set =
> +			(uintptr_t)obj->package.elements[IS_PASS_SET].string.pointer;
> +		kfree(obj);
> +		return sprintf(buf, "%d\n", po_data[instance_id].is_password_set);
> +	}
> +	return -EIO;
> +}
> +
> +struct kobj_attribute po_is_pass_set =
> +		__ATTR_RO(is_password_set);
> +
> +static ssize_t current_password_store(struct kobject *kobj,
> +				      struct kobj_attribute *attr,
> +				      const char *buf, size_t count)
> +{
> +	char *p = memchr(buf, '\n', count);
> +	int ret;
> +
> +	if (p != NULL)
> +		*p = '\0';
> +	if (strlen(buf) > MAX_BUFF)
> +		return -EINVAL;
> +
> +	ret = set_current_password(kobj->name, buf);
> +	return ret ? ret : count;
> +}
> +
> +struct kobj_attribute po_current_password =
> +		__ATTR_WO(current_password);
> +
> +static ssize_t new_password_store(struct kobject *kobj,
> +				  struct kobj_attribute *attr,
> +				  const char *buf, size_t count)
> +{
> +	char *p = memchr(buf, '\n', count);
> +	int ret;
> +
> +	if (p != NULL)
> +		*p = '\0';
> +	if (strlen(buf) > MAX_BUFF)
> +		return -EINVAL;
> +
> +	ret = set_new_password(kobj->name, buf);
> +	return ret ? ret : count;
> +}
> +
> +struct kobj_attribute po_new_password =
> +		__ATTR_WO(new_password);
> +
> +attribute_n_property_show(min_password_length, po);
> +struct kobj_attribute po_min_pass_length =
> +		__ATTR_RO(min_password_length);
> +
> +attribute_n_property_show(max_password_length, po);
> +struct kobj_attribute po_max_pass_length =
> +		__ATTR_RO(max_password_length);
> +
> +attribute_s_property_show(type, po);
> +struct kobj_attribute po_type =
> +	__ATTR_RO(type);
> +
> +static struct attribute *po_attrs[] = {
> +	&po_is_pass_set.attr,
> +	&po_min_pass_length.attr,
> +	&po_max_pass_length.attr,
> +	&po_current_password.attr,
> +	&po_new_password.attr,
> +	&po_type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group po_attr_group = {
> +	.attrs = po_attrs,
> +};
> +
> +int alloc_po_data(void)
> +{
> +	int ret = 0;
> +
> +	po_instances_count = get_instance_count(DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> +	po_data = kzalloc((sizeof(struct po_data) * po_instances_count), GFP_KERNEL);
> +	if (!po_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_po_data() - Populate all properties of an instance under password object attribute
> + * @po_obj: ACPI object with password object data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + **/
> +int populate_po_data(union acpi_object *po_obj, int instance_id, struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &po_attr_group);
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&po_mutex);
> +	strncpy_attr(po_data[instance_id].attribute_name, po_obj[ATTR_NAME].string.pointer);
> +	po_data[instance_id].is_password_set = (uintptr_t)po_obj[IS_PASS_SET].string.pointer;
> +	po_data[instance_id].min_password_length = (uintptr_t)po_obj[MIN_PASS_LEN].string.pointer;
> +	po_data[instance_id].max_password_length = (uintptr_t) po_obj[MAX_PASS_LEN].string.pointer;
> +	strncpy_attr(po_data[instance_id].type, "password_object");
> +	mutex_unlock(&po_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_po_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_po_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &po_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&po_mutex);
> +	kfree(po_data);
> +	mutex_unlock(&po_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-passwordattr-interface.c b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> new file mode 100644
> index 000000000000..d105608cbb86
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> @@ -0,0 +1,200 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to SET password methods under BIOS attributes interface GUID
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include <linux/nls.h>
> +#include <linux/wmi.h>
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(call_mutex);
> +extern struct dell_wmi_sysman_priv wmi_priv;
> +
> +static int call_password_interface(struct wmi_device *wdev, char *in_args, size_t size)
> +{
> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_buffer input;
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int ret = -EIO;
> +
> +	input.length =  (acpi_size) size;
> +	input.pointer = in_args;
> +	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +	obj = (union acpi_object *)output.pointer;
> +	if (obj->type == ACPI_TYPE_INTEGER)
> +		ret = obj->integer.value;
> +
> +	kfree(output.pointer);
> +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
> +	return map_wmi_error(ret);
> +}
> +
> +/**
> + * get_current_password() - Get the current stored password value
> + * @password_type: The type of password to store
> + **/
> +static char *get_current_password(const char *password_type)
> +{
> +	if (strcmp(password_type, "Admin") == 0)
> +		return wmi_priv.current_admin_password;
> +	if (strcmp(password_type, "System") == 0)
> +		return wmi_priv.current_system_password;
> +	dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s", password_type);
> +	return NULL;
> +}
> +
> +/**
> + * set_current_password() - Store current password
> + * @password_type: The type of password to store
> + * @current: The current value
> + *
> + * Sets the current value of the password.
> + * This is used for:
> + *  - Resetting password
> + *  - Basis for any functions requiring password to execute
> + **/
> +int set_current_password(const char *password_type, const char *cur)
> +{
> +	char *current_password = get_current_password(password_type);
> +
> +	if (!current_password)
> +		return -ENODEV;
> +	strncpy(current_password, cur, (strlen(cur) + 1));
> +	return 0;
> +}
> +
> +/**
> + * set_new_password() - Sets a system admin password
> + * @password_type: The type of password to set
> + * @new: The new password
> + *
> + * Sets the password using plaintext interface
> + **/
> +int set_new_password(const char *password_type, const char *new)
> +{
> +	char *current_password, *type_value, *old_value, *new_value;
> +	size_t security_area_size, string_area_size, buffer_size;
> +	u8 *type_len, *old_len, *new_len;
> +	char *buffer;
> +	int ret;
> +
> +	/* only allow one password set at a time */
> +	mutex_lock(&call_mutex);
> +	if (!wmi_priv.password_attr_wdev) {
> +		ret = -ENODEV;
> +		pr_err("no WMI backend bound");
> +		goto out_close_mutex;
> +	}
> +	current_password = get_current_password(password_type);
> +	if (!current_password) {
> +		ret = -ENODEV;
> +		goto out_close_mutex;
> +	}
> +
> +	/* build/calculate buffer */
> +	security_area_size = calculate_security_buffer();
> +	string_area_size = (strlen(password_type) + strlen(current_password) + strlen(new))*2;
> +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 3;
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer) {
> +		ret = -ENOMEM;
> +		goto out_close_mutex;
> +	}
> +
> +	/* build security area */
> +	if (strlen(current_password) > 0)
> +		populate_security_buffer(buffer, current_password);
> +
> +	/* build variables to set */
> +	type_len = buffer + security_area_size;
> +	type_value = type_len + sizeof(u16);
> +	*type_len = utf8s_to_utf16s(password_type, strlen(password_type), UTF16_HOST_ENDIAN,
> +				    (wchar_t *) type_value, MAX_BUFF) * 2;
> +	if (*type_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_cleanup;
> +	}
> +
> +	old_len = type_value + *type_len;
> +	old_value = old_len + sizeof(u16);
> +	*old_len = utf8s_to_utf16s(current_password, strlen(current_password), UTF16_HOST_ENDIAN,
> +				   (wchar_t *) old_value, MAX_BUFF) * 2;
> +	if (*old_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_cleanup;
> +	}
> +
> +	new_len = old_value + *old_len;
> +	new_value = new_len + sizeof(u16);
> +	*new_len = utf8s_to_utf16s(new, strlen(new), UTF16_HOST_ENDIAN,
> +				   (wchar_t *) new_value, MAX_BUFF) * 2;
> +	if (*new_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_cleanup;
> +	}
> +
> +	ret = call_password_interface(wmi_priv.password_attr_wdev, buffer, buffer_size);
> +	/* update current password so commands work after reset */
> +	if (!ret)
> +		ret = set_current_password(password_type, new);
> +	/* explain to user the detailed failure reason */
> +	else if (ret == -EOPNOTSUPP)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured");
> +	else if (ret == -EACCES)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
> +
> +out_cleanup:
> +	kfree(buffer);
> +
> +out_close_mutex:
> +	mutex_unlock(&call_mutex);
> +
> +	return ret;
> +}
> +
> +static int dell_wmi_bios_attr_pass_interface_probe(struct wmi_device *wdev, const void *context)
> +{
> +	wmi_priv.password_attr_wdev = wdev;
> +	return 0;
> +}
> +
> +static int dell_wmi_bios_attr_pass_interface_remove(struct wmi_device *wdev)
> +{
> +	mutex_lock(&call_mutex);
> +	wmi_priv.password_attr_wdev = NULL;
> +	mutex_unlock(&call_mutex);
> +	return 0;
> +}
> +
> +static const struct wmi_device_id dell_wmi_bios_attr_pass_interface_id_table[] = {
> +	{ .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
> +	{ },
> +};
> +static struct wmi_driver dell_wmi_bios_attr_pass_interface_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME"-password"
> +	},
> +	.probe = dell_wmi_bios_attr_pass_interface_probe,
> +	.remove = dell_wmi_bios_attr_pass_interface_remove,
> +	.id_table = dell_wmi_bios_attr_pass_interface_id_table,
> +};
> +
> +int init_dell_wmi_bios_attr_pass_interface(void)
> +{
> +	return wmi_driver_register(&dell_wmi_bios_attr_pass_interface_driver);
> +}
> +
> +void exit_dell_wmi_bios_attr_pass_interface(void)
> +{
> +	wmi_driver_unregister(&dell_wmi_bios_attr_pass_interface_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_pass_interface_id_table);
> diff --git a/drivers/platform/x86/dell-wmi-string-attributes.c b/drivers/platform/x86/dell-wmi-string-attributes.c
> new file mode 100644
> index 000000000000..397de6fb13a3
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-string-attributes.c
> @@ -0,0 +1,177 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to string type attributes under BIOS String GUID for use with
> + * dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(str_mutex);
> +extern struct mutex kset_mutex;
> +
> +enum string_properties {MIN_LEN = 6, MAX_LEN};
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct str_data {
> +	char display_name_language_code[MAX_BUFF];
> +	char attribute_name[MAX_BUFF];
> +	char display_name[MAX_BUFF];
> +	char default_value[MAX_BUFF];
> +	char current_value[MAX_BUFF];
> +	char modifier[MAX_BUFF];
> +	int min_length;
> +	int max_length;
> +	char type[MAX_BUFF];
> +};
> +
> +static struct str_data *str_data;
> +static int str_instances_count;
> +get_instance_id(str);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +	instance_id = get_str_instance_id(kobj);
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;
> +		strncpy_attr(str_data[instance_id].current_value,
> +			obj->package.elements[CURRENT_VAL].string.pointer);
> +		kfree(obj);
> +		return sprintf(buf, "%s\n", str_data[instance_id].current_value);
> +	}
> +	return -EIO;
> +}
> +
> +/**
> + * validate_str_input() - Validate input of current_value against min and max lengths
> + * @instance_id: The instance on which input is validated
> + * @buf: Input value
> + **/
> +int validate_str_input(int instance_id, const char *buf)
> +{
> +	int in_len = strlen(buf);
> +
> +	if ((in_len >= str_data[instance_id].min_length) &&
> +	(in_len <= str_data[instance_id].max_length))
> +		return 0;
> +
> +	return -EINVAL;
> +}
> +
> +attribute_s_property_show(display_name_language_code, str);
> +static struct kobj_attribute str_displ_langcode =
> +		__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, str);
> +struct kobj_attribute str_displ_name =
> +		__ATTR_RO(display_name);
> +
> +attribute_s_property_show(default_value, str);
> +struct kobj_attribute str_default_val =
> +		__ATTR_RO(default_value);
> +
> +attribute_property_store(current_value, str);
> +struct kobj_attribute str_current_val =
> +		__ATTR_RW(current_value);
> +
> +attribute_s_property_show(modifier, str);
> +struct kobj_attribute str_modifier =
> +		__ATTR_RO(modifier);
> +
> +attribute_n_property_show(min_length, str);
> +struct kobj_attribute str_min_length =
> +		__ATTR_RO(min_length);
> +
> +attribute_n_property_show(max_length, str);
> +struct kobj_attribute str_max_length =
> +		__ATTR_RO(max_length);
> +
> +attribute_s_property_show(type, str);
> +struct kobj_attribute str_type =
> +	__ATTR_RO(type);
> +
> +static struct attribute *str_attrs[] = {
> +	&str_displ_langcode.attr,
> +	&str_displ_name.attr,
> +	&str_default_val.attr,
> +	&str_current_val.attr,
> +	&str_modifier.attr,
> +	&str_min_length.attr,
> +	&str_max_length.attr,
> +	&str_type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group str_attr_group = {
> +	.attrs = str_attrs,
> +};
> +
> +int alloc_str_data(void)
> +{
> +	int ret = 0;
> +
> +	str_instances_count = get_instance_count(DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> +	str_data = kzalloc((sizeof(struct str_data) * str_instances_count), GFP_KERNEL);
> +	if (!str_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_enum_data() - Populate all properties of an instance under string attribute
> + * @str_obj: ACPI object with integer data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + **/
> +int populate_str_data(union acpi_object *str_obj, int instance_id, struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &str_attr_group);
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&str_mutex);
> +	strncpy_attr(str_data[instance_id].attribute_name, str_obj[ATTR_NAME].string.pointer);
> +	strncpy_attr(str_data[instance_id].display_name_language_code,
> +		str_obj[DISPL_NAME_LANG_CODE].string.pointer);
> +	strncpy_attr(str_data[instance_id].display_name, str_obj[DISPLAY_NAME].string.pointer);
> +	strncpy_attr(str_data[instance_id].default_value, str_obj[DEFAULT_VAL].string.pointer);
> +	strncpy_attr(str_data[instance_id].current_value, str_obj[CURRENT_VAL].string.pointer);
> +	strncpy_attr(str_data[instance_id].modifier, str_obj[MODIFIER].string.pointer);
> +	str_data[instance_id].min_length = (uintptr_t)str_obj[MIN_LEN].string.pointer;
> +	str_data[instance_id].max_length = (uintptr_t) str_obj[MAX_LEN].string.pointer;
> +	strncpy_attr(str_data[instance_id].type, "string");
> +	mutex_unlock(&str_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_str_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_str_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &str_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&str_mutex);
> +	kfree(str_data);
> +	mutex_unlock(&str_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.c b/drivers/platform/x86/dell-wmi-sysman-attributes.c
> new file mode 100644
> index 000000000000..139d8f5d3d8e
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-sysman-attributes.c
> @@ -0,0 +1,572 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Common methods for use with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/dmi.h>
> +#include <linux/wmi.h>
> +#include "dell-wmi-sysman-attributes.h"
> +
> +DEFINE_MUTEX(kset_mutex);
> +
> +#define MAX_TYPES  4
> +
> +static struct platform_device *platform_device;
> +
> +static struct platform_driver platform_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME,
> +	},
> +};
> +
> +/* global structure used by multiple WMI interfaces */
> +struct dell_wmi_sysman_priv wmi_priv;
> +
> +/* attribute directory under platform dev */
> +struct kset *main_dir_kset;
> +
> +/* reset bios to defaults */
> +static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
> +static int reset_option = -1;
> +
> +/**
> + * calculate_security_buffer() - determines size of security buffer for authentication scheme
> + *
> + * Currently only supported type is Admin password
> + **/
> +size_t calculate_security_buffer(void)
> +{
> +	if (strlen(wmi_priv.current_admin_password) > 0) {
> +		return (sizeof(u32) * 2) +
> +			strlen(wmi_priv.current_admin_password) +
> +			strlen(wmi_priv.current_admin_password) % 2;
> +	}
> +	return sizeof(u32) * 2;
> +}
> +
> +/**
> + * populate_security_buffer() - builds a security buffer for authentication scheme
> + * @buffer: the buffer to populate
> + * @authentication: the authentication content
> + *
> + * Currently only supported type is PLAIN TEXT
> + **/
> +void populate_security_buffer(char *buffer, char *authentication)
> +{
> +	char *auth = buffer + sizeof(u32)*2;
> +	u32 *sectype = (u32 *) buffer;
> +	u32 *seclen = sectype + 1;
> +	/* plain text */
> +	*sectype = 1;
> +	*seclen = strlen(authentication);
> +	strncpy(auth, authentication, *seclen);
> +}
> +
> +/**
> + * map_wmi_error() - map errors from WMI methods to kernel error codes
> + **/
> +int map_wmi_error(int error_code)
> +{
> +	switch (error_code) {
> +	case 0:
> +		/* success */
> +		return 0;
> +	case 1:
> +		/* failed */
> +		return -EIO;
> +	case 2:
> +		/* invalid parameter */
> +		return -EINVAL;
> +	case 3:
> +		/* access denied */
> +		return -EACCES;
> +	case 4:
> +		/* not supported */
> +		return -EOPNOTSUPP;
> +	case 5:
> +		/* memory error */
> +		return -ENOMEM;
> +	case 6:
> +		/* protocol error */
> +		return -EPROTO;
> +	}
> +	/* unspecified error */
> +	return -EIO;
> +}
> +
> +/**
> + * reset_bios_show() - sysfs implementaton for read reset_bios
> + * @kobj: Kernel object for this attribute
> + * @attr: Kernel object attribute
> + * @buf: The buffer to display to userspace
> + **/
> +static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	char *start = buf;
> +	int i;
> +
> +	for (i = 0; i < MAX_TYPES; i++) {
> +		if (i == reset_option)
> +			buf += sprintf(buf, "[%s] ", reset_types[i]);
> +		else
> +			buf += sprintf(buf, "%s ", reset_types[i]);
> +	}
> +	buf += sprintf(buf, "\n");
> +	return buf-start;
> +}
> +
> +/**
> + * reset_bios_store() - sysfs implementaton for write reset_bios
> + * @kobj: Kernel object for this attribute
> + * @attr: Kernel object attribute
> + * @buf: The buffer from userspace
> + * @count: the size of the buffer from userspace
> + **/
> +static ssize_t reset_bios_store(struct kobject *kobj,
> +				struct kobj_attribute *attr, const char *buf, size_t count)
> +{
> +	int len, ret, i;
> +	int type = -1;
> +	char *p;
> +
> +	p = memchr(buf, '\n', count);
> +	if (p != NULL)
> +		*p = '\0';
> +	len = p ? p - buf : count;
> +
> +	for (i = 0; i < MAX_TYPES; i++) {
> +		if (len == strlen(reset_types[i])
> +		    && !strncmp(buf, reset_types[i], len)) {
> +			type = i;
> +			break;
> +		}
> +	}
> +
> +	if (type < 0 || type >= MAX_TYPES) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	ret = set_bios_defaults(type);
> +	dev_dbg(&platform_device->dev, "reset all attributes request type %d: %d", type, ret);
> +	if (ret) {
> +		ret = -EINVAL;
> +	} else {
> +		reset_option = type;
> +		ret = count;
> +	}
> +
> +out:
> +	return ret;
> +}
> +
> +/**
> + * pending_reboot_show() - sysfs implementaton for read pending_reboot
> + * @kobj: Kernel object for this attribute
> + * @attr: Kernel object attribute
> + * @buf: The buffer to display to userspace
> + *
> + * Stores default value as 0
> + * When current_value is changed this attribute is set to 1 to notify reboot may be required
> + **/
> +static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
> +				   char *buf)
> +{
> +	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
> +}
> +
> +static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
> +static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
> +
> +
> +/**
> + * create_reset_bios() - Creates reset_bios and pending_reboot attributes
> + **/
> +static int create_reset_bios(void)
> +{
> +	int ret = sysfs_create_file(&main_dir_kset->kobj, &reset_bios.attr);
> +
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "could not create reset_bios file");
> +		return ret;
> +	}
> +
> +	ret = sysfs_create_file(&main_dir_kset->kobj, &pending_reboot.attr);
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "could not create changing_pending_reboot file");
> +		sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
> +	}
> +	return ret;
> +}
> +
> +static void release_reset_bios_data(void)
> +{
> +	sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
> +	sysfs_remove_file(&main_dir_kset->kobj, &pending_reboot.attr);
> +}
> +
> +static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
> +			      char *buf)
> +{
> +	struct kobj_attribute *kattr;
> +	ssize_t ret = -EIO;
> +
> +	kattr = container_of(attr, struct kobj_attribute, attr);
> +	if (kattr->show)
> +		ret = kattr->show(kobj, kattr, buf);
> +	return ret;
> +}
> +
> +static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
> +			       const char *buf, size_t count)
> +{
> +	struct kobj_attribute *kattr;
> +	ssize_t ret = -EIO;
> +
> +	kattr = container_of(attr, struct kobj_attribute, attr);
> +	if (kattr->store)
> +		ret = kattr->store(kobj, kattr, buf, count);
> +	return ret;
> +}
> +
> +const struct sysfs_ops kobj_sysfs_ops = {
> +	.show	= kobj_attr_show,
> +	.store	= kobj_attr_store,
> +};
compile issue (x86_64, make defconfig, make menuconifg selected all pdx86
options built before using git am)  after git am building and selecting y for
the new config's defined by this patch:

Intel SCU IPC utility driver (INTEL_SCU_IPC_UTIL) [Y/n/m/?] y
UPD     include/config/kernel.release
UPD     include/generated/utsrelease.h
CALL    scripts/checksyscalls.sh
CALL    scripts/atomic/check-atomics.sh
DESCEND  objtool
CHK     include/generated/compile.h
CC      init/version.o
AR      init/built-in.a
CC      kernel/sys.o
CC      kernel/module.o
CC      kernel/trace/trace.o
AR      kernel/trace/built-in.a
AR      kernel/built-in.a
CC drivers/base/firmware_loader/fallback_table.o
CC      drivers/base/firmware_loader/main.o
CC drivers/base/firmware_loader/fallback.o
AR drivers/base/firmware_loader/built-in.a
AR      drivers/base/built-in.a
CC drivers/platform/x86/dell-wmi-sysman-attributes.o
CC drivers/platform/x86/dell-wmi-enum-attributes.o
CC drivers/platform/x86/dell-wmi-int-attributes.o
CC drivers/platform/x86/dell-wmi-string-attributes.o
CC drivers/platform/x86/dell-wmi-passobj-attributes.o
CC drivers/platform/x86/dell-wmi-passwordattr-interface.o
CC drivers/platform/x86/dell-wmi-biosattr-interface.o
AR drivers/platform/x86/built-in.a
AR drivers/platform/built-in.a
AR drivers/built-in.a
CC net/ethtool/ioctl.o
AR net/ethtool/built-in.a
AR net/built-in.a
GEN .version
CHK include/generated/compile.h
UPD include/generated/compile.h
CC init/version.o
AR init/built-in.a
LD vmlinux.o
drivers/platform/x86/dell-wmi-sysman-attributes.o:(.rodata+0x20): multiple
definition of `kobj_sysfs_ops'
lib/kobject.o:(.rodata+0x40): first defined here
Makefile:1166: recipe for target 'vmlinux' failed
make: *** [vmlinux] Error 1

--mark

Hans de Goede Sept. 14, 2020, 10:11 a.m. UTC | #2

Hi,

Like last-time I will split this review in 2,
this first email will focus on the sysfs API/ABI part only.

On 9/4/20 4:28 PM, Divya Bharathi wrote:
> The Dell WMI Systems Management Driver provides a sysfs
> interface for systems management to enable BIOS configuration
> capability on certain Dell Systems.
> 
> This driver allows user to configure Dell systems with a
> uniform common interface. To facilitate this, the patch
> introduces a generic way for driver to be able to create
> configurable BIOS Attributes available in Setup (F2) screen.
> 
> Cc: Hans de Goede <[e-mail]>
> Cc: Andy Shevchenko <[e-mail]>
> 
> Co-developed-by: Mario Limonciello <[e-mail]>
> Signed-off-by: Mario Limonciello <[e-mail]>
> Co-developed-by: Prasanth KSR <[e-mail]>
> Signed-off-by: Prasanth KSR <[e-mail]>
> Signed-off-by: Divya Bharathi <[e-mail]>
> ---
> 
> ChangeLog from v1 to v2:
>   - use pr_fmt instead of pr_err(DRIVER_NAME
>   - re-order variables reverse xmas tree order
>   - correct returns of -1 to error codes
>   - correct usage of {} on some split line statements
>   - Refine all documentation deficiencies suggested by Hans
>   - Merge all attributes to a single directory
>   - Overhaul WMI interface interaction as suggested by Hans
>     * Move WMI driver registration to start of module
>     * Remove usage of lists that only use first entry for WMI interfaces
>     * Create a global structure shared across interface source files
>     * Make get_current_password function static
>     * Remove get_pending changes function, shared across global structure now.
> - Overhaul use of mutexes
>     * Make kset list mutex shared across source files
>     * Remove unneeded dell-wmi-sysman call_mutex
>     * Keep remaining call_mutexes in WMI functions
> - Move security area calculation into a function
> - Use NLS helper for utf8->utf16 conversion
> 
>   .../testing/sysfs-platform-dell-wmi-sysman    | 126 ++++
>   MAINTAINERS                                   |   9 +
>   drivers/platform/x86/Kconfig                  |  12 +
>   drivers/platform/x86/Makefile                 |   8 +
>   .../x86/dell-wmi-biosattr-interface.c         | 198 ++++++
>   .../platform/x86/dell-wmi-enum-attributes.c   | 214 +++++++
>   .../platform/x86/dell-wmi-int-attributes.c    | 195 ++++++
>   .../x86/dell-wmi-passobj-attributes.c         | 168 +++++
>   .../x86/dell-wmi-passwordattr-interface.c     | 200 ++++++
>   .../platform/x86/dell-wmi-string-attributes.c | 177 ++++++
>   .../platform/x86/dell-wmi-sysman-attributes.c | 572 ++++++++++++++++++
>   .../platform/x86/dell-wmi-sysman-attributes.h | 132 ++++
>   12 files changed, 2011 insertions(+)
>   create mode 100644 Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
>   create mode 100644 drivers/platform/x86/dell-wmi-biosattr-interface.c
>   create mode 100644 drivers/platform/x86/dell-wmi-enum-attributes.c
>   create mode 100644 drivers/platform/x86/dell-wmi-int-attributes.c
>   create mode 100644 drivers/platform/x86/dell-wmi-passobj-attributes.c
>   create mode 100644 drivers/platform/x86/dell-wmi-passwordattr-interface.c
>   create mode 100644 drivers/platform/x86/dell-wmi-string-attributes.c
>   create mode 100644 drivers/platform/x86/dell-wmi-sysman-attributes.c
>   create mode 100644 drivers/platform/x86/dell-wmi-sysman-attributes.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman b/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
> new file mode 100644
> index 000000000000..e4b608275ea4
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
> @@ -0,0 +1,126 @@
> +What:		/sys/devices/platform/dell-wmi-sysman/attributes/
> +Date:		December 2020
> +KernelVersion:	5.10
> +Contact:	Divya Bharathi <[e-mail]>,
> +		Mario Limonciello <[e-mail]>,
> +		Prasanth KSR <[e-mail]>
> +Description:
> +		The Dell WMI Systems Management Driver provides a sysfs interface
> +		for systems management software to enable BIOS configuration
> +		capability on certain Dell systems. This directory exposes
> +		interfaces for interacting with BIOS attributes.
> +
> +		Attributes can accept a set of pre-defined valid values or a range of
> +		numerical values or a string. An atribute can accept float as well,
> +		if so '.' is used as decimal separator.

Please replace: "An atribute" with "A numerical attribute", note this also fixes
a typo in attribute. Also this still deels a bit handwavy, if currently all used
numerical values are integers, lets just forget about floats for now and add
floats later as a separate type, to me that seems more sensible then having
a magical numerical type which can represent both.

> +
> +		Also, BIOS Admin password and System Password can be set, reset or
> +		cleared using these attributes. An "Admin" password is used for
> +		preventing modification to the BIOS settings. A "System" password is
> +		required to boot a machine.

Please add a paragraph for the type sysfs-attribute here, e.g.:

		type: Give the type of <attr>, this may be one of "integer", "string",
		"enum" and "password"


> +
> +		current_value:	A file that can be read to obtain the current
> +		value of the <attr>
> +
> +		This file can also be written to in order to update
> +		the value of a <attr>
> +
> +		default_value:	A file that can be read to obtain the default
> +		value of the <attr>
> +
> +		display_name:	A file that can be read to obtain a user friendly
> +		description of the at <attr>
> +
> +		display_name_language_code:	A file that can be read to obtain
> +		the IETF language tag corresponding to the "display_name" of the <attr>
> +
> +		modifier:	A file that can be read to obtain attribute-level
> +		dependency rule. It says an attribute X will become read-only or
> +		suppressed,	if attribute Y is not configured.
> +		For example, AutoOnHr becomes read-only if AutoOn is disabled

This still does not specify the syntax, if I do:

cat /sys/devices/platform/dell-wmi-sysman/attributes/AutoOnHr/modifier

What will the output be? and how should other software interpret that output?

> +
> +		possible_value:	A file that can be read to obtain the possible
> +		values of the <attr>. Values are separated using semi-colon.

This one is valid for enums only, right ? The above sysfs-attributes are all
generic, which is fine. But please add some separate headings for attributes which
are only value for a specific type, e.g.:

"enum"-type specific attributes:

	possible_value:...

Also shouldn't this be named possible_values? note the extra 's' at the end.

> +
> +		value_modifier:	A file that can be read to obtain value-level
> +		dependency. This file is similar to modifier but here, an attribute's
> +		current value will be forcefully changed based dependent attributes
> +		value.
> +		For example, current value of LegacyOrom will become Disabled if
> +		SecureBoot is Enabled.
> +

Please group this together with modifier (in the section with sysfs-attributes
which are common to all types) and also this needs a lot better explanation / documentation.

> +		lower_bound:	A file that can be read to obtain the lower
> +		bound value of the <attr>
> +
> +		upper_bound:	A file that can be read to obtain the upper
> +		bound value of the <attr>
> +
> +		scalar_increment:	A file that can be read to obtain the
> +		resolution of the incremental value this attribute accepts.

Please put all 3 under:

"integer"-type specific attributes:

So that you get:

"integer"-type specific attributes:

	lower_bound:	...

	upper_bound:	...

	scalar_increment:	...

Also please rename lower_bound to min_value and upper_bound to max_value,
this makes its clearer that they apply to current_value and in general
makes it easier to understand what they do.


> +
> +		max_length:	A file that can be read to obtain the maximum
> +		length value of the <attr>
> +
> +		min_length:	A file that can be read to obtain the minimum
> +		length value of the <attr>

Please put these 2 under:

"string"-type specific attributes:


> +
> +		is_password_set:	A file that can be read
> +		to obtain flag to see if a password is set on <attr>
> +
> +		max_password_length:	A file that can be read to obtain the
> +		maximum length of the Password
> +
> +		min_password_length:	A file that can be read to obtain the
> +		minimum length of the Password
> +
> +		current_password: A write only value used for privileged access
> +		such as setting attributes when a system or admin password is set
> +		or resetting to a new password
> +
> +		new_password: A write only value that when used in tandem with
> +		current_password will reset a system or admin password.

Please put all 5 of these under:

"password"-type specific attributes:


> +
> +What:		/sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
> +Date:		December 2020
> +KernelVersion:	5.10
> +Contact:	Divya Bharathi <[e-mail]>,
> +		Mario Limonciello <[e-mail]>,
> +		Prasanth KSR <[e-mail]>
> +Description:
> +		This attribute can be used to reset the BIOS Configuration.
> +		Specifically, it tells which type of reset BIOS configuration is being
> +		requested on the host.
> +
> +		Reading from it returns a list of supported options encoded as:
> +
> +			'builtinsafe' (Built in safe configuration profile)
> +			'lastknowngood' (Last known good saved configuration profile)
> +			'factory' (Default factory settings configuration profile)
> +			'custom' (Custom saved configuration profile)
> +
> +		The currently selected option is printed in square brackets as
> +		shown below:
> +
> +		# echo "factory" > sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
> +
> +		# cat sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
> +		# builtinsafe lastknowngood [factory] custom
> +
> +		Note that any changes to this attribute requires a reboot
> +		for changes to take effect.
> +
> +What:		/sys/devices/platform/dell-wmi-sysman/attributes/pending_reboot
> +Date:		December 2020
> +KernelVersion:	5.10
> +Contact:	Divya Bharathi <[e-mail]>,
> +		Mario Limonciello <[e-mail]>,
> +		Prasanth KSR <[e-mail]>
> +Description:
> +		A read-only attribute reads 1 if a reboot is necessary to apply
> +		pending BIOS attribute changes.
> +
> +			0:	All BIOS attributes setting are current
> +			1:	A reboot is necessary to get pending BIOS attribute changes
> +				applied
> +
> +


Regards,

Hans

Hans de Goede Sept. 14, 2020, 11:58 a.m. UTC | #3

Hi,

Like last-time I will split this review in 2,
this second email focusses on the code.

Note I'm still mainly focusing on the overall
structure and how you handle locking here.

Further reviews (of newer versions) will look
at the per function code in more detail.

On 9/4/20 4:28 PM, Divya Bharathi wrote:
> diff --git a/drivers/platform/x86/dell-wmi-biosattr-interface.c b/drivers/platform/x86/dell-wmi-biosattr-interface.c
> new file mode 100644
> index 000000000000..dda38d448fec
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-biosattr-interface.c
> @@ -0,0 +1,198 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to SET methods under BIOS attributes interface GUID for use
> + * with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include <linux/nls.h>
> +#include <linux/wmi.h>
> +#include "dell-wmi-sysman-attributes.h"
> +
> +#define SETDEFAULTVALUES_METHOD_ID					0x02
> +#define SETBIOSDEFAULTS_METHOD_ID					0x03
> +#define SETATTRIBUTE_METHOD_ID						0x04
> +
> +static DEFINE_MUTEX(call_mutex);

By doing this you still declare one lock per file, so code from 2 files could
be accessing the wmi_priv struct and be making WMI calls at the same time.

Please add a mutex to the dell_wmi_sysman_priv struct, like this:

In dell-wmi-sysman-attributes.h:

struct dell_wmi_sysman_priv {
	struct mutex mutex;
         char current_admin_password[MAX_BUFF];
         char current_system_password[MAX_BUFF];
         struct wmi_device *password_attr_wdev;
         struct wmi_device *bios_attr_wdev;
         bool pending_changes;
};

And in dell-wmi-sysman-attributes.c:

struct dell_wmi_sysman_priv wmi_priv = {
	.mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
};

And then whenever you need the mutex call:

	mutex_lock(&wmi_priv.mutex);
	...
	mutex_unlock(&wmi_priv.mutex);

And use this in all files.

> +extern struct dell_wmi_sysman_priv wmi_priv;

Please move this to dell-wmi-sysman-attributes.h .


> +
> +static int call_biosattributes_interface(struct wmi_device *wdev, char *in_args, size_t size,
> +					int method_id)
> +{
> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_buffer input;
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int ret = -EIO;
> +
> +	input.length =  (acpi_size) size;
> +	input.pointer = in_args;
> +	status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +	obj = (union acpi_object *)output.pointer;
> +	if (obj->type == ACPI_TYPE_INTEGER)
> +		ret = obj->integer.value;
> +
> +	kfree(output.pointer);
> +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);

Why are you generating an uevent here? I think this needs a comment (or it should be removed).

> +	return map_wmi_error(ret);
> +}
> +
> +/**
> + * set_attribute() - Update an attribute value
> + * @a_name: The attribute name
> + * @a_value: The attribute value
> + *
> + * Sets an attribute to new value
> + **/
> +int set_attribute(const char *a_name, const char *a_value)
> +{
> +	size_t security_area_size, string_area_size, buffer_size;
> +	char *attribute_name, *attribute_value;
> +	u8 *name_len, *value_len;
> +	char *buffer;
> +	int ret;
> +
> +	/* build/calculate buffer */
> +	security_area_size = calculate_security_buffer();
> +	string_area_size = (strlen(a_name) + strlen(a_value))*2;
> +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 2;
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	/* build security area */
> +	if (strlen(wmi_priv.current_admin_password) > 0)
> +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
> +
> +	/* build variables to set */
> +	name_len = buffer + security_area_size;
> +	attribute_name = name_len + sizeof(u16);
> +	*name_len = utf8s_to_utf16s(a_name, strlen(a_name), UTF16_HOST_ENDIAN,
> +				    (wchar_t *) attribute_name, MAX_BUFF) * 2;
> +	if (*name_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_set_attribute;
> +	}
> +
> +	value_len = (u8 *) attribute_name + *name_len;
> +	attribute_value = value_len + sizeof(u16);
> +	*value_len = utf8s_to_utf16s(a_value, strlen(a_value), UTF16_HOST_ENDIAN,
> +				    (wchar_t *) attribute_value, MAX_BUFF) * 2;
> +	if (*value_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_set_attribute;
> +	}
> +
> +	mutex_lock(&call_mutex);
> +	if (!wmi_priv.bios_attr_wdev) {
> +		ret = -ENODEV;
> +		pr_err("no WMI backend bound");
> +		goto out_set_attribute;
> +	}

It is probably better to move this to the top, as I mentioned in my reply
to Mario, you could add something like this to the top of each function,
even before allocating the buffer and filling it.

     mutex_lock(&wmi_priv.mutex);

     if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
         ret = -ENODEV;
         goto out_set_attribute;
     }

Note this requires that you initialize the buf pointer to NULL
wehn declaring it.

Having this at the top of each function establishes a pattern where
it easy for a reader of the code to:

a) See that the check is present when checking that the driver being
unbound is checked everywhere

b) Ignore the check as "boilerplate" when looking at other parts of
the code

Also note that I dropped the pr_err. Users should not go around and
unbind drivers, if they then we should not crash. But the user asked
for it, so just returning -ENODEV without logging an error should be
fine.


> +
> +	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
> +					    buffer, buffer_size,
> +					    SETATTRIBUTE_METHOD_ID);
> +	if (ret == -EOPNOTSUPP)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured");
> +	else if (ret == -EACCES)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
> +
> +	wmi_priv.pending_changes = 1;
> +out_set_attribute:
> +	kfree(buffer);
> +	mutex_unlock(&call_mutex);
> +
> +	return ret;
> +}
> +
> +/**
> + * set_bios_defaults() - Resets BIOS defaults
> + * @deftype: the type of BIOS value reset to issue.
> + *
> + * Resets BIOS defaults
> + **/
> +int set_bios_defaults(u8 deftype)
> +{
> +	size_t security_area_size, buffer_size;
> +	size_t integer_area_size = sizeof(u8);
> +	u8 *defaultType;
> +	char *buffer;
> +	int ret;
> +

You are missing the check for the driver being unbound here,
this nicely documents why you should have this at the top
of each function making WMI calls.

> +	security_area_size = calculate_security_buffer();
> +	buffer_size = security_area_size + integer_area_size;
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	/* build security area */
> +	if (strlen(wmi_priv.current_admin_password) > 0)
> +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
> +
> +	mutex_lock(&call_mutex);
> +	if (!wmi_priv.bios_attr_wdev) {
> +		ret = -ENODEV;
> +		pr_err("no WMI backend bound");
> +		goto out_bios_defaults;
> +	}
> +
> +	defaultType = buffer + security_area_size;
> +	*defaultType = deftype;
> +
> +	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer, buffer_size,
> +					    SETBIOSDEFAULTS_METHOD_ID);
> +	if (ret)
> +		dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed: %d", ret);
> +	wmi_priv.pending_changes = 1;
> +out_bios_defaults:
> +	kfree(buffer);
> +	mutex_unlock(&call_mutex);
> +
> +	return ret;
> +}
> +
> +static int dell_wmi_bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
> +{
> +	wmi_priv.bios_attr_wdev = wdev;
> +	return 0;
> +}
> +
> +static int dell_wmi_bios_attr_set_interface_remove(struct wmi_device *wdev)
> +{
> +	mutex_lock(&call_mutex);
> +	wmi_priv.bios_attr_wdev = NULL;
> +	mutex_unlock(&call_mutex);
> +	return 0;
> +}
> +
> +static const struct wmi_device_id dell_wmi_bios_attr_set_interface_id_table[] = {
> +	{ .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
> +	{ },
> +};
> +static struct wmi_driver dell_wmi_bios_attr_set_interface_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME"-set"
> +	},
> +	.probe = dell_wmi_bios_attr_set_interface_probe,
> +	.remove = dell_wmi_bios_attr_set_interface_remove,
> +	.id_table = dell_wmi_bios_attr_set_interface_id_table,
> +};
> +
> +int init_dell_wmi_bios_attr_set_interface(void)
> +{
> +	return wmi_driver_register(&dell_wmi_bios_attr_set_interface_driver);
> +}
> +
> +void exit_dell_wmi_bios_attr_set_interface(void)
> +{
> +	wmi_driver_unregister(&dell_wmi_bios_attr_set_interface_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_set_interface_id_table);
> diff --git a/drivers/platform/x86/dell-wmi-enum-attributes.c b/drivers/platform/x86/dell-wmi-enum-attributes.c
> new file mode 100644
> index 000000000000..f2370f067b6d
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-enum-attributes.c
> @@ -0,0 +1,214 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to enumeration type attributes under BIOS Enumeration GUID for use
> + * with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(enum_mutex);
> +extern struct mutex kset_mutex;

Please just use the global wmi_priv.mutex to replace both of these.

> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct enumeration_data {
> +	char display_name_language_code[MAX_BUFF];
> +	char attribute_name[MAX_BUFF];
> +	char display_name[MAX_BUFF];
> +	char default_value[MAX_BUFF];
> +	char current_value[MAX_BUFF];
> +	char modifier[MAX_BUFF];
> +	int value_modifier_count;
> +	char value_modifier[MAX_BUFF];
> +	int possible_value_count;
> +	char possible_value[MAX_BUFF];
> +	char type[MAX_BUFF];
> +};
> +
> +static struct enumeration_data *enumeration_data;
> +static int enumeration_instances_count;

Please store these 2 in the global wmi_priv data.

Also there is a lot of overlap between structs like
struct enumeration_data, struct integer_data, etc.

I think it would be good to make a single struct
attr_data, which contains fields for all the
supported types.

I also see a lot of overlapping code between:

drivers/platform/x86/dell-wmi-enum-attributes.c
drivers/platform/x86/dell-wmi-int-attributes.c
drivers/platform/x86/dell-wmi-string-attributes.c

I think that folding the data structures together
will help with also unifying that code into a
single dell-wmi-std-attributes.c file.

> +get_instance_id(enumeration);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +	instance_id = get_enumeration_instance_id(kobj);

If you unify the integer, string and enum code then this just becomes:
get_std_instance_id(kobj)

> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;

> +		strncpy_attr(enumeration_data[instance_id].current_value,
> +		       obj->package.elements[CURRENT_VAL].string.pointer);
So these 2 lines seem to be the only thing which is different for current_value_show,
between enums, ints and strings, so you can put a simple switch-case on the type here.

> +		kfree(obj);
> +		return sprintf(buf, "%s\n", enumeration_data[instance_id].current_value);
> +	}
> +	return -EIO;
> +} > +
> +/**
> + * validate_enumeration_input() - Validate input of current_value against possible values
> + * @instance_id: The instance on which input is validated
> + * @buf: Input value
> + **/
> +int validate_enumeration_input(int instance_id, const char *buf)
> +{
> +	char *options, *tmp, *p;
> +	int ret = -EINVAL;
> +
> +	options = tmp = kstrdup((enumeration_data[instance_id].possible_value), GFP_KERNEL);
> +	if (!options)
> +		return -ENOMEM;
> +
> +	while ((p = strsep(&options, ";")) != NULL) {
> +		if (!*p)
> +			continue;
> +		if (!strncasecmp(p, buf, strlen(p))) {
> +			ret = 0;
> +			break;
> +		}
> +	}
> +
> +	kfree(tmp);
> +	return ret;
> +}

For the validate functions you can keep all 3 in the new
dell-wmi-std-attributes.c file and then call the right one through a
switch-case based on the type.

> +
> +attribute_s_property_show(display_name_language_code, enumeration);
> +static struct kobj_attribute displ_langcode =
> +		__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, enumeration);
> +struct kobj_attribute displ_name =
> +		__ATTR_RO(display_name);
> +
> +attribute_s_property_show(default_value, enumeration);
> +struct kobj_attribute default_val =
> +		__ATTR_RO(default_value);
> +
> +attribute_property_store(current_value, enumeration);
> +struct kobj_attribute current_val =
> +		__ATTR_RW(current_value);
> +
> +attribute_s_property_show(modifier, enumeration);
> +struct kobj_attribute modifier =
> +		__ATTR_RO(modifier);
> +
> +attribute_s_property_show(value_modifier, enumeration);
> +struct kobj_attribute value_modfr =
> +		__ATTR_RO(value_modifier);
> +
> +attribute_s_property_show(possible_value, enumeration);
> +struct kobj_attribute poss_val =
> +		__ATTR_RO(possible_value);
> +
> +attribute_s_property_show(type, enumeration);
> +struct kobj_attribute type =
> +		__ATTR_RO(type);
> +
> +static struct attribute *enumeration_attrs[] = {
> +	&displ_langcode.attr,
> +	&displ_name.attr,
> +	&default_val.attr,
> +	&current_val.attr,
> +	&modifier.attr,
> +	&value_modfr.attr,
> +	&poss_val.attr,
> +	&type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group enumeration_attr_group = {
> +	.attrs = enumeration_attrs,
> +};
> +
> +int alloc_enum_data(void)
> +{
> +	int ret = 0;
> +
> +	enumeration_instances_count = get_instance_count(DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> +	enumeration_data = kzalloc((sizeof(struct enumeration_data) * enumeration_instances_count),
> +					GFP_KERNEL);
> +	if (!enumeration_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +

The rest of the file is mostly identical between strings, ints and enums.

> +/**
> + * populate_enum_data() - Populate all properties of an instance under enumeration attribute
> + * @enumeration_obj: ACPI object with enumeration data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + **/
> +int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
> +			struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> +	int i, next_obj;
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&enum_mutex);
> +	strncpy_attr(enumeration_data[instance_id].attribute_name,
> +		enumeration_obj[ATTR_NAME].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].display_name_language_code,
> +		enumeration_obj[DISPL_NAME_LANG_CODE].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].display_name,
> +		enumeration_obj[DISPLAY_NAME].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].default_value,
> +		enumeration_obj[DEFAULT_VAL].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].current_value,
> +		enumeration_obj[CURRENT_VAL].string.pointer);
> +	strncpy_attr(enumeration_data[instance_id].modifier,
> +		enumeration_obj[MODIFIER].string.pointer);
> +
> +	next_obj = MODIFIER + 1;
> +
> +	enumeration_data[instance_id].value_modifier_count =
> +		(uintptr_t)enumeration_obj[next_obj].string.pointer;
> +
> +	for (i = 0; i < enumeration_data[instance_id].value_modifier_count; i++) {
> +		strcat(enumeration_data[instance_id].value_modifier,
> +			enumeration_obj[++next_obj].string.pointer);
> +		strcat(enumeration_data[instance_id].value_modifier, ";");
> +	}
> +
> +	enumeration_data[instance_id].possible_value_count =
> +		(uintptr_t) enumeration_obj[++next_obj].string.pointer;
> +
> +	for (i = 0; i < enumeration_data[instance_id].possible_value_count; i++) {
> +		strcat(enumeration_data[instance_id].possible_value,
> +			enumeration_obj[++next_obj].string.pointer);
> +		strcat(enumeration_data[instance_id].possible_value, ";");
> +	}
> +	strncpy_attr(enumeration_data[instance_id].type, "enumeration");
> +	mutex_unlock(&enum_mutex);
> +
> +out:
> +	return retval;
> +}


I guess you may also need a switch-case based on the
type in the populare function.

> +
> +/**
> + * exit_enum_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_enum_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &enumeration_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&enum_mutex);
> +	kfree(enumeration_data);
> +	mutex_unlock(&enum_mutex);
> +}

Since there is now only 1 kset for the main dir, you are now
calling sysfs_remove_group 4 times (for all the different times)
on each entry in the attributes dir. I guess this may fail silently,
but it still is not good. So this needs to be fixed.

The remarks to this file also apply to the:

drivers/platform/x86/dell-wmi-int-attributes.c
drivers/platform/x86/dell-wmi-string-attributes.c

files.

> diff --git a/drivers/platform/x86/dell-wmi-int-attributes.c b/drivers/platform/x86/dell-wmi-int-attributes.c
> new file mode 100644
> index 000000000000..d922d4f73ce9
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-int-attributes.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to integer type attributes under BIOS Integer GUID for use with
> + * dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(int_mutex);
> +extern struct mutex kset_mutex;
> +
> +enum int_properties {LOWER_BOUND = 6, UPPER_BOUND, SCALAR_INCR};
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct integer_data {
> +	char display_name_language_code[MAX_BUFF];
> +	char attribute_name[MAX_BUFF];
> +	char display_name[MAX_BUFF];
> +	int default_value;
> +	int current_value;
> +	char modifier[MAX_BUFF];
> +	int lower_bound;
> +	int upper_bound;
> +	int scalar_increment;
> +	char type[MAX_BUFF];
> +};
> +
> +static struct integer_data *integer_data;
> +static int integer_instances_count;
> +get_instance_id(integer);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +	instance_id = get_integer_instance_id(kobj);
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR > +		integer_data[instance_id].current_value =
> +			(uintptr_t)obj->package.elements[CURRENT_VAL].string.pointer;
> +		kfree(obj);
> +		return sprintf(buf, "%d\n", integer_data[instance_id].current_value);
> +	}
> +	return -EIO;
> +} > +
> +/**
> + * 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
> + **/
> +int validate_integer_input(int instance_id, const char *buf)
> +{
> +	int ret = -EINVAL;
> +	int in_val;
> +
> +	if (kstrtoint(buf, 0, &in_val))
> +		return ret;
> +	if ((in_val >= integer_data[instance_id].lower_bound) &&
> +	(in_val <= integer_data[instance_id].upper_bound))
> +		ret = 0;
> +
> +	return ret;
> +}
> +
> +attribute_s_property_show(display_name_language_code, integer);
> +static struct kobj_attribute integer_displ_langcode =
> +	__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, integer);
> +struct kobj_attribute integer_displ_name =
> +	__ATTR_RO(display_name);
> +
> +attribute_n_property_show(default_value, integer);
> +struct kobj_attribute integer_default_val =
> +	__ATTR_RO(default_value);
> +
> +attribute_property_store(current_value, integer);
> +struct kobj_attribute integer_current_val =
> +	__ATTR_RW(current_value);
> +
> +attribute_s_property_show(modifier, integer);
> +struct kobj_attribute integer_modifier =
> +	__ATTR_RO(modifier);
> +
> +attribute_n_property_show(lower_bound, integer);
> +struct kobj_attribute integer_lower_bound =
> +	__ATTR_RO(lower_bound);
> +
> +attribute_n_property_show(upper_bound, integer);
> +struct kobj_attribute integer_upper_bound =
> +	__ATTR_RO(upper_bound);
> +
> +attribute_n_property_show(scalar_increment, integer);
> +struct kobj_attribute integer_scalar_increment =
> +	__ATTR_RO(scalar_increment);
> +
> +attribute_s_property_show(type, integer);
> +struct kobj_attribute integer_type =
> +	__ATTR_RO(type);
> +
> +static struct attribute *integer_attrs[] = {
> +	&integer_displ_langcode.attr,
> +	&integer_displ_name.attr,
> +	&integer_default_val.attr,
> +	&integer_current_val.attr,
> +	&integer_modifier.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 alloc_int_data(void)
> +{
> +	int ret = 0;
> +
> +	integer_instances_count = get_instance_count(DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> +	integer_data = kzalloc((sizeof(struct integer_data) * integer_instances_count), GFP_KERNEL);
> +	if (!integer_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_enum_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 populate_int_data(union acpi_object *integer_obj, int instance_id,
> +			struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &integer_attr_group);
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&int_mutex);
> +	strncpy_attr(integer_data[instance_id].attribute_name,
> +		integer_obj[ATTR_NAME].string.pointer);
> +	strncpy_attr(integer_data[instance_id].display_name_language_code,
> +		integer_obj[DISPL_NAME_LANG_CODE].string.pointer);
> +	strncpy_attr(integer_data[instance_id].display_name,
> +		integer_obj[DISPLAY_NAME].string.pointer);
> +	integer_data[instance_id].default_value =
> +		(uintptr_t)integer_obj[DEFAULT_VAL].string.pointer;
> +	integer_data[instance_id].current_value =
> +		(uintptr_t)integer_obj[CURRENT_VAL].string.pointer;
> +	strncpy_attr(integer_data[instance_id].modifier, integer_obj[MODIFIER].string.pointer);
> +	integer_data[instance_id].lower_bound =
> +		(uintptr_t)integer_obj[LOWER_BOUND].string.pointer;
> +	integer_data[instance_id].upper_bound =
> +		(uintptr_t)integer_obj[UPPER_BOUND].string.pointer;
> +	integer_data[instance_id].scalar_increment =
> +		(uintptr_t)integer_obj[SCALAR_INCR].string.pointer;
> +	strncpy_attr(integer_data[instance_id].type, "integer");
> +	mutex_unlock(&int_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_int_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_int_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &integer_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&int_mutex);
> +	kfree(integer_data);
> +	mutex_unlock(&int_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-passobj-attributes.c b/drivers/platform/x86/dell-wmi-passobj-attributes.c
> new file mode 100644
> index 000000000000..87bb7772bb18
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-passobj-attributes.c
> @@ -0,0 +1,168 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to password object type attributes under BIOS Password Object GUID for
> + * use with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(po_mutex);
> +extern struct mutex kset_mutex;
> +
> +enum po_properties {IS_PASS_SET = 1, MIN_PASS_LEN, MAX_PASS_LEN};
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct po_data {
> +	char attribute_name[MAX_BUFF];
> +	int is_password_set;
> +	int min_password_length;
> +	int max_password_length;
> +	char type[MAX_BUFF];
> +};
> +
> +static struct po_data *po_data;
> +static int po_instances_count;
> +get_instance_id(po);
> +
> +static ssize_t is_password_set_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id = get_po_instance_id(kobj);
> +
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;
> +		po_data[instance_id].is_password_set =
> +			(uintptr_t)obj->package.elements[IS_PASS_SET].string.pointer;
> +		kfree(obj);
> +		return sprintf(buf, "%d\n", po_data[instance_id].is_password_set);
> +	}
> +	return -EIO;
> +}
> +
> +struct kobj_attribute po_is_pass_set =
> +		__ATTR_RO(is_password_set);
> +
> +static ssize_t current_password_store(struct kobject *kobj,
> +				      struct kobj_attribute *attr,
> +				      const char *buf, size_t count)
> +{
> +	char *p = memchr(buf, '\n', count);
> +	int ret;
> +
> +	if (p != NULL)
> +		*p = '\0';
> +	if (strlen(buf) > MAX_BUFF)
> +		return -EINVAL;
> +
> +	ret = set_current_password(kobj->name, buf);
> +	return ret ? ret : count;
> +}
> +
> +struct kobj_attribute po_current_password =
> +		__ATTR_WO(current_password);
> +
> +static ssize_t new_password_store(struct kobject *kobj,
> +				  struct kobj_attribute *attr,
> +				  const char *buf, size_t count)
> +{
> +	char *p = memchr(buf, '\n', count);
> +	int ret;
> +
> +	if (p != NULL)
> +		*p = '\0';
> +	if (strlen(buf) > MAX_BUFF)
> +		return -EINVAL;
> +
> +	ret = set_new_password(kobj->name, buf);
> +	return ret ? ret : count;
> +}
> +
> +struct kobj_attribute po_new_password =
> +		__ATTR_WO(new_password);
> +
> +attribute_n_property_show(min_password_length, po);
> +struct kobj_attribute po_min_pass_length =
> +		__ATTR_RO(min_password_length);
> +
> +attribute_n_property_show(max_password_length, po);
> +struct kobj_attribute po_max_pass_length =
> +		__ATTR_RO(max_password_length);
> +
> +attribute_s_property_show(type, po);
> +struct kobj_attribute po_type =
> +	__ATTR_RO(type);
> +
> +static struct attribute *po_attrs[] = {
> +	&po_is_pass_set.attr,
> +	&po_min_pass_length.attr,
> +	&po_max_pass_length.attr,
> +	&po_current_password.attr,
> +	&po_new_password.attr,
> +	&po_type.attr,
> +	NULL,
> +};

So these don't have a current_value, display_name, etc. standard sysfs entries,
so maybe put the passwords in a separate:
/sys/devices/platform/dell-wmi-sysman/passwords

Dir, otherwise saying that all attributes have a current_value, display_name, etc.
in the sysfs ABI documentation is incorrect. Doing this also gives you 2 dirs / ksets
for the cleanup, 1 for all std attributes and 1 for passwords which also solves
the cleanup problem I pointed out above.

Having 2 dirs, 1 for normal attributes and 1 for passwords, also matches the
2 WMI interfaces, so I believe that this is the right way to go.


> +
> +static const struct attribute_group po_attr_group = {
> +	.attrs = po_attrs,
> +};
> +
> +int alloc_po_data(void)
> +{
> +	int ret = 0;
> +
> +	po_instances_count = get_instance_count(DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> +	po_data = kzalloc((sizeof(struct po_data) * po_instances_count), GFP_KERNEL);
> +	if (!po_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_po_data() - Populate all properties of an instance under password object attribute
> + * @po_obj: ACPI object with password object data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + **/
> +int populate_po_data(union acpi_object *po_obj, int instance_id, struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &po_attr_group);
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&po_mutex);
> +	strncpy_attr(po_data[instance_id].attribute_name, po_obj[ATTR_NAME].string.pointer);
> +	po_data[instance_id].is_password_set = (uintptr_t)po_obj[IS_PASS_SET].string.pointer;
> +	po_data[instance_id].min_password_length = (uintptr_t)po_obj[MIN_PASS_LEN].string.pointer;
> +	po_data[instance_id].max_password_length = (uintptr_t) po_obj[MAX_PASS_LEN].string.pointer;
> +	strncpy_attr(po_data[instance_id].type, "password_object");
> +	mutex_unlock(&po_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_po_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_po_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &po_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&po_mutex);
> +	kfree(po_data);
> +	mutex_unlock(&po_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-passwordattr-interface.c b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> new file mode 100644
> index 000000000000..d105608cbb86
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> @@ -0,0 +1,200 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to SET password methods under BIOS attributes interface GUID
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include <linux/nls.h>
> +#include <linux/wmi.h>
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(call_mutex);
> +extern struct dell_wmi_sysman_priv wmi_priv;

See my comments on drivers/platform/x86/dell-wmi-biosattr-interface.c about this.

> +
> +static int call_password_interface(struct wmi_device *wdev, char *in_args, size_t size)
> +{
> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_buffer input;
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int ret = -EIO;
> +
> +	input.length =  (acpi_size) size;
> +	input.pointer = in_args;
> +	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +	obj = (union acpi_object *)output.pointer;
> +	if (obj->type == ACPI_TYPE_INTEGER)
> +		ret = obj->integer.value;
> +
> +	kfree(output.pointer);
> +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
> +	return map_wmi_error(ret);
> +}
> +
> +/**
> + * get_current_password() - Get the current stored password value
> + * @password_type: The type of password to store
> + **/
> +static char *get_current_password(const char *password_type)
> +{
> +	if (strcmp(password_type, "Admin") == 0)
> +		return wmi_priv.current_admin_password;
> +	if (strcmp(password_type, "System") == 0)
> +		return wmi_priv.current_system_password;
> +	dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s", password_type);
> +	return NULL;
> +}

Since you have the passwords directly available in wmi_priv now this
function seems no longer necessary ?

> +
> +/**
> + * set_current_password() - Store current password
> + * @password_type: The type of password to store
> + * @current: The current value
> + *
> + * Sets the current value of the password.
> + * This is used for:
> + *  - Resetting password
> + *  - Basis for any functions requiring password to execute
> + **/
> +int set_current_password(const char *password_type, const char *cur)
> +{
> +	char *current_password = get_current_password(password_type);
> +
> +	if (!current_password)
> +		return -ENODEV;
> +	strncpy(current_password, cur, (strlen(cur) + 1));
> +	return 0;
> +}

Same.

> +
> +/**
> + * set_new_password() - Sets a system admin password
> + * @password_type: The type of password to set
> + * @new: The new password
> + *
> + * Sets the password using plaintext interface
> + **/
> +int set_new_password(const char *password_type, const char *new)
> +{
> +	char *current_password, *type_value, *old_value, *new_value;
> +	size_t security_area_size, string_area_size, buffer_size;
> +	u8 *type_len, *old_len, *new_len;
> +	char *buffer;
> +	int ret;
> +
> +	/* only allow one password set at a time */

This comment is somewhat confusing, I guess it is meant for the
mutex_lock call, but the mutex e.g. also protects wmi_priv.password_attr_wdev
from changing while this code is running, please drop the comment.

> +	mutex_lock(&call_mutex);
> +	if (!wmi_priv.password_attr_wdev) {
> +		ret = -ENODEV;
> +		pr_err("no WMI backend bound");
> +		goto out_close_mutex;
> +	}
> +	current_password = get_current_password(password_type);
> +	if (!current_password) {
> +		ret = -ENODEV;
> +		goto out_close_mutex;
> +	}
> +
> +	/* build/calculate buffer */
> +	security_area_size = calculate_security_buffer();
> +	string_area_size = (strlen(password_type) + strlen(current_password) + strlen(new))*2;
> +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 3;
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer) {
> +		ret = -ENOMEM;
> +		goto out_close_mutex;
> +	}
> +
> +	/* build security area */
> +	if (strlen(current_password) > 0)
> +		populate_security_buffer(buffer, current_password);
> +
> +	/* build variables to set */
> +	type_len = buffer + security_area_size;
> +	type_value = type_len + sizeof(u16);
> +	*type_len = utf8s_to_utf16s(password_type, strlen(password_type), UTF16_HOST_ENDIAN,
> +				    (wchar_t *) type_value, MAX_BUFF) * 2;
> +	if (*type_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_cleanup;
> +	}
> +
> +	old_len = type_value + *type_len;
> +	old_value = old_len + sizeof(u16);
> +	*old_len = utf8s_to_utf16s(current_password, strlen(current_password), UTF16_HOST_ENDIAN,
> +				   (wchar_t *) old_value, MAX_BUFF) * 2;
> +	if (*old_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_cleanup;
> +	}
> +
> +	new_len = old_value + *old_len;
> +	new_value = new_len + sizeof(u16);
> +	*new_len = utf8s_to_utf16s(new, strlen(new), UTF16_HOST_ENDIAN,
> +				   (wchar_t *) new_value, MAX_BUFF) * 2;
> +	if (*new_len < 0) {
> +		ret = -EINVAL;
> +		pr_err("UTF16 conversion failed");
> +		goto out_cleanup;
> +	}
> +
> +	ret = call_password_interface(wmi_priv.password_attr_wdev, buffer, buffer_size);
> +	/* update current password so commands work after reset */
> +	if (!ret)
> +		ret = set_current_password(password_type, new);
> +	/* explain to user the detailed failure reason */
> +	else if (ret == -EOPNOTSUPP)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured");
> +	else if (ret == -EACCES)
> +		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
> +
> +out_cleanup:
> +	kfree(buffer);
> +
> +out_close_mutex:
> +	mutex_unlock(&call_mutex);

You don't need 2 separate out_foo labels, kfree(NULL) is a no-op, so
if you initialize buffer to NULL when you declare it you can use a single
out label.

> +
> +	return ret;
> +}
> +
> +static int dell_wmi_bios_attr_pass_interface_probe(struct wmi_device *wdev, const void *context)
> +{
> +	wmi_priv.password_attr_wdev = wdev;
> +	return 0;
> +}
> +
> +static int dell_wmi_bios_attr_pass_interface_remove(struct wmi_device *wdev)
> +{
> +	mutex_lock(&call_mutex);
> +	wmi_priv.password_attr_wdev = NULL;
> +	mutex_unlock(&call_mutex);
> +	return 0;
> +}
> +
> +static const struct wmi_device_id dell_wmi_bios_attr_pass_interface_id_table[] = {
> +	{ .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
> +	{ },
> +};
> +static struct wmi_driver dell_wmi_bios_attr_pass_interface_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME"-password"
> +	},
> +	.probe = dell_wmi_bios_attr_pass_interface_probe,
> +	.remove = dell_wmi_bios_attr_pass_interface_remove,
> +	.id_table = dell_wmi_bios_attr_pass_interface_id_table,
> +};
> +
> +int init_dell_wmi_bios_attr_pass_interface(void)
> +{
> +	return wmi_driver_register(&dell_wmi_bios_attr_pass_interface_driver);
> +}
> +
> +void exit_dell_wmi_bios_attr_pass_interface(void)
> +{
> +	wmi_driver_unregister(&dell_wmi_bios_attr_pass_interface_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_pass_interface_id_table);
> diff --git a/drivers/platform/x86/dell-wmi-string-attributes.c b/drivers/platform/x86/dell-wmi-string-attributes.c
> new file mode 100644
> index 000000000000..397de6fb13a3
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-string-attributes.c
> @@ -0,0 +1,177 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to string type attributes under BIOS String GUID for use with
> + * dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#include "dell-wmi-sysman-attributes.h"
> +
> +static DEFINE_MUTEX(str_mutex);
> +extern struct mutex kset_mutex;
> +
> +enum string_properties {MIN_LEN = 6, MAX_LEN};
> +
> +/* kept variable names same as in sysfs file name for sysfs_show macro definition */
> +struct str_data {
> +	char display_name_language_code[MAX_BUFF];
> +	char attribute_name[MAX_BUFF];
> +	char display_name[MAX_BUFF];
> +	char default_value[MAX_BUFF];
> +	char current_value[MAX_BUFF];
> +	char modifier[MAX_BUFF];
> +	int min_length;
> +	int max_length;
> +	char type[MAX_BUFF];
> +};
> +
> +static struct str_data *str_data;
> +static int str_instances_count;
> +get_instance_id(str);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +	instance_id = get_str_instance_id(kobj);
> +	if (instance_id >= 0) {
> +		union acpi_object *obj;
> +
> +		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> +		if (!obj)
> +			return -AE_ERROR;
> +		strncpy_attr(str_data[instance_id].current_value,
> +			obj->package.elements[CURRENT_VAL].string.pointer);
> +		kfree(obj);
> +		return sprintf(buf, "%s\n", str_data[instance_id].current_value);
> +	}
> +	return -EIO;
> +}
> +
> +/**
> + * validate_str_input() - Validate input of current_value against min and max lengths
> + * @instance_id: The instance on which input is validated
> + * @buf: Input value
> + **/
> +int validate_str_input(int instance_id, const char *buf)
> +{
> +	int in_len = strlen(buf);
> +
> +	if ((in_len >= str_data[instance_id].min_length) &&
> +	(in_len <= str_data[instance_id].max_length))
> +		return 0;
> +
> +	return -EINVAL;
> +}
> +
> +attribute_s_property_show(display_name_language_code, str);
> +static struct kobj_attribute str_displ_langcode =
> +		__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, str);
> +struct kobj_attribute str_displ_name =
> +		__ATTR_RO(display_name);
> +
> +attribute_s_property_show(default_value, str);
> +struct kobj_attribute str_default_val =
> +		__ATTR_RO(default_value);
> +
> +attribute_property_store(current_value, str);
> +struct kobj_attribute str_current_val =
> +		__ATTR_RW(current_value);
> +
> +attribute_s_property_show(modifier, str);
> +struct kobj_attribute str_modifier =
> +		__ATTR_RO(modifier);
> +
> +attribute_n_property_show(min_length, str);
> +struct kobj_attribute str_min_length =
> +		__ATTR_RO(min_length);
> +
> +attribute_n_property_show(max_length, str);
> +struct kobj_attribute str_max_length =
> +		__ATTR_RO(max_length);
> +
> +attribute_s_property_show(type, str);
> +struct kobj_attribute str_type =
> +	__ATTR_RO(type);
> +
> +static struct attribute *str_attrs[] = {
> +	&str_displ_langcode.attr,
> +	&str_displ_name.attr,
> +	&str_default_val.attr,
> +	&str_current_val.attr,
> +	&str_modifier.attr,
> +	&str_min_length.attr,
> +	&str_max_length.attr,
> +	&str_type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group str_attr_group = {
> +	.attrs = str_attrs,
> +};
> +
> +int alloc_str_data(void)
> +{
> +	int ret = 0;
> +
> +	str_instances_count = get_instance_count(DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> +	str_data = kzalloc((sizeof(struct str_data) * str_instances_count), GFP_KERNEL);
> +	if (!str_data)
> +		ret = -ENOMEM;
> +	return ret;
> +}
> +
> +/**
> + * populate_enum_data() - Populate all properties of an instance under string attribute
> + * @str_obj: ACPI object with integer data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + **/
> +int populate_str_data(union acpi_object *str_obj, int instance_id, struct kobject *attr_name_kobj)
> +{
> +	int retval = sysfs_create_group(attr_name_kobj, &str_attr_group);
> +
> +	if (retval)
> +		goto out;
> +
> +	mutex_lock(&str_mutex);
> +	strncpy_attr(str_data[instance_id].attribute_name, str_obj[ATTR_NAME].string.pointer);
> +	strncpy_attr(str_data[instance_id].display_name_language_code,
> +		str_obj[DISPL_NAME_LANG_CODE].string.pointer);
> +	strncpy_attr(str_data[instance_id].display_name, str_obj[DISPLAY_NAME].string.pointer);
> +	strncpy_attr(str_data[instance_id].default_value, str_obj[DEFAULT_VAL].string.pointer);
> +	strncpy_attr(str_data[instance_id].current_value, str_obj[CURRENT_VAL].string.pointer);
> +	strncpy_attr(str_data[instance_id].modifier, str_obj[MODIFIER].string.pointer);
> +	str_data[instance_id].min_length = (uintptr_t)str_obj[MIN_LEN].string.pointer;
> +	str_data[instance_id].max_length = (uintptr_t) str_obj[MAX_LEN].string.pointer;
> +	strncpy_attr(str_data[instance_id].type, "string");
> +	mutex_unlock(&str_mutex);
> +
> +out:
> +	return retval;
> +}
> +
> +/**
> + * exit_str_attributes() - Clear all attribute data
> + * @kset: The kset to free
> + *
> + * Clears all data allocated for this group of attributes
> + **/
> +void exit_str_attributes(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		sysfs_remove_group(pos, &str_attr_group);
> +	}
> +	mutex_unlock(&kset_mutex);
> +	mutex_lock(&str_mutex);
> +	kfree(str_data);
> +	mutex_unlock(&str_mutex);
> +}
> diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.c b/drivers/platform/x86/dell-wmi-sysman-attributes.c
> new file mode 100644
> index 000000000000..139d8f5d3d8e
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-sysman-attributes.c
> @@ -0,0 +1,572 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Common methods for use with dell-wmi-sysman
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/dmi.h>
> +#include <linux/wmi.h>
> +#include "dell-wmi-sysman-attributes.h"
> +
> +DEFINE_MUTEX(kset_mutex);
> +
> +#define MAX_TYPES  4
> +
> +static struct platform_device *platform_device;
> +
> +static struct platform_driver platform_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME,
> +	},
> +};
> +
> +/* global structure used by multiple WMI interfaces */
> +struct dell_wmi_sysman_priv wmi_priv;
> +
> +/* attribute directory under platform dev */
> +struct kset *main_dir_kset;
> +
> +/* reset bios to defaults */
> +static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
> +static int reset_option = -1;
> +
> +/**
> + * calculate_security_buffer() - determines size of security buffer for authentication scheme
> + *
> + * Currently only supported type is Admin password
> + **/
> +size_t calculate_security_buffer(void)
> +{
> +	if (strlen(wmi_priv.current_admin_password) > 0) {
> +		return (sizeof(u32) * 2) +
> +			strlen(wmi_priv.current_admin_password) +
> +			strlen(wmi_priv.current_admin_password) % 2;
> +	}
> +	return sizeof(u32) * 2;
> +}
> +
> +/**
> + * populate_security_buffer() - builds a security buffer for authentication scheme
> + * @buffer: the buffer to populate
> + * @authentication: the authentication content
> + *
> + * Currently only supported type is PLAIN TEXT
> + **/
> +void populate_security_buffer(char *buffer, char *authentication)
> +{
> +	char *auth = buffer + sizeof(u32)*2;
> +	u32 *sectype = (u32 *) buffer;
> +	u32 *seclen = sectype + 1;
> +	/* plain text */
> +	*sectype = 1;
> +	*seclen = strlen(authentication);
> +	strncpy(auth, authentication, *seclen);
> +}
> +
> +/**
> + * map_wmi_error() - map errors from WMI methods to kernel error codes
> + **/
> +int map_wmi_error(int error_code)
> +{
> +	switch (error_code) {
> +	case 0:
> +		/* success */
> +		return 0;
> +	case 1:
> +		/* failed */
> +		return -EIO;
> +	case 2:
> +		/* invalid parameter */
> +		return -EINVAL;
> +	case 3:
> +		/* access denied */
> +		return -EACCES;
> +	case 4:
> +		/* not supported */
> +		return -EOPNOTSUPP;
> +	case 5:
> +		/* memory error */
> +		return -ENOMEM;
> +	case 6:
> +		/* protocol error */
> +		return -EPROTO;
> +	}
> +	/* unspecified error */
> +	return -EIO;
> +}
> +
> +/**
> + * reset_bios_show() - sysfs implementaton for read reset_bios
> + * @kobj: Kernel object for this attribute
> + * @attr: Kernel object attribute
> + * @buf: The buffer to display to userspace
> + **/
> +static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	char *start = buf;
> +	int i;
> +
> +	for (i = 0; i < MAX_TYPES; i++) {
> +		if (i == reset_option)
> +			buf += sprintf(buf, "[%s] ", reset_types[i]);
> +		else
> +			buf += sprintf(buf, "%s ", reset_types[i]);
> +	}
> +	buf += sprintf(buf, "\n");
> +	return buf-start;
> +}
> +
> +/**
> + * reset_bios_store() - sysfs implementaton for write reset_bios
> + * @kobj: Kernel object for this attribute
> + * @attr: Kernel object attribute
> + * @buf: The buffer from userspace
> + * @count: the size of the buffer from userspace
> + **/
> +static ssize_t reset_bios_store(struct kobject *kobj,
> +				struct kobj_attribute *attr, const char *buf, size_t count)
> +{
> +	int len, ret, i;
> +	int type = -1;
> +	char *p;
> +
> +	p = memchr(buf, '\n', count);
> +	if (p != NULL)
> +		*p = '\0';
> +	len = p ? p - buf : count;
> +
> +	for (i = 0; i < MAX_TYPES; i++) {
> +		if (len == strlen(reset_types[i])
> +		    && !strncmp(buf, reset_types[i], len)) {
> +			type = i;
> +			break;
> +		}
> +	}
> +
> +	if (type < 0 || type >= MAX_TYPES) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	ret = set_bios_defaults(type);
> +	dev_dbg(&platform_device->dev, "reset all attributes request type %d: %d", type, ret);
> +	if (ret) {
> +		ret = -EINVAL;
> +	} else {
> +		reset_option = type;
> +		ret = count;
> +	}
> +
> +out:
> +	return ret;
> +}
> +
> +/**
> + * pending_reboot_show() - sysfs implementaton for read pending_reboot
> + * @kobj: Kernel object for this attribute
> + * @attr: Kernel object attribute
> + * @buf: The buffer to display to userspace
> + *
> + * Stores default value as 0
> + * When current_value is changed this attribute is set to 1 to notify reboot may be required
> + **/
> +static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
> +				   char *buf)
> +{
> +	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
> +}
> +
> +static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
> +static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
> +
> +
> +/**
> + * create_reset_bios() - Creates reset_bios and pending_reboot attributes
> + **/
> +static int create_reset_bios(void)
> +{
> +	int ret = sysfs_create_file(&main_dir_kset->kobj, &reset_bios.attr);
> +
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "could not create reset_bios file");
> +		return ret;
> +	}
> +
> +	ret = sysfs_create_file(&main_dir_kset->kobj, &pending_reboot.attr);
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "could not create changing_pending_reboot file");
> +		sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
> +	}
> +	return ret;
> +}
> +
> +static void release_reset_bios_data(void)
> +{
> +	sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
> +	sysfs_remove_file(&main_dir_kset->kobj, &pending_reboot.attr);
> +}
> +
> +static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
> +			      char *buf)
> +{
> +	struct kobj_attribute *kattr;
> +	ssize_t ret = -EIO;
> +
> +	kattr = container_of(attr, struct kobj_attribute, attr);
> +	if (kattr->show)
> +		ret = kattr->show(kobj, kattr, buf);
> +	return ret;
> +}
> +
> +static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
> +			       const char *buf, size_t count)
> +{
> +	struct kobj_attribute *kattr;
> +	ssize_t ret = -EIO;
> +
> +	kattr = container_of(attr, struct kobj_attribute, attr);
> +	if (kattr->store)
> +		ret = kattr->store(kobj, kattr, buf, count);
> +	return ret;
> +}
> +
> +const struct sysfs_ops kobj_sysfs_ops = {
> +	.show	= kobj_attr_show,
> +	.store	= kobj_attr_store,
> +};
> +
> +static void attr_name_release(struct kobject *kobj)
> +{
> +	kfree(kobj);
> +}
> +
> +static struct kobj_type attr_name_ktype = {
> +	.release	= attr_name_release,
> +	.sysfs_ops	= &kobj_sysfs_ops,
> +};
> +
> +/**
> + * strncpy_attr - Copy a length-limited, NULL-terminated string with bound checks
> + * @dest: Where to copy the string to
> + * @src: Where to copy the string from
> + **/
> +void strncpy_attr(char *dest, char *src)
> +{
> +	size_t len = strlen(src) + 1;
> +
> +	if (len > 1 && len < MAX_BUFF)
> +		strncpy(dest, src, len);
> +}
> +
> +/**
> + * get_wmiobj_pointer() - Get Content of WMI block for particular instance
> + * @instance_id: WMI instance ID
> + * @guid_string: WMI GUID (in str form)
> + *
> + * Fetches the content for WMI block (instance_id) under GUID (guid_string)
> + * Caller must kfree the return
> + **/
> +union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
> +{
> +	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_status status;
> +
> +	status = wmi_query_block(guid_string, instance_id, &out);
> +
> +	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
> +}
> +
> +/**
> + * get_instance_count() - Compute total number of instances under guid_string
> + * @guid_string: WMI GUID (in string form)
> + **/
> +int get_instance_count(const char *guid_string)
> +{
> +	union acpi_object *wmi_obj = NULL;
> +	int i = 0;
> +
> +	do {
> +		kfree(wmi_obj);
> +		wmi_obj = get_wmiobj_pointer(i, guid_string);
> +		i++;
> +	} while (wmi_obj);
> +
> +	return (i-1);
> +}
> +
> +/**
> + * alloc_attributes_data() - Allocate attributes data for a particular type
> + * @attr_type: Attribute type to allocate
> + **/
> +static int alloc_attributes_data(int attr_type)
> +{
> +	int retval = 0;
> +
> +	switch (attr_type) {
> +	case ENUM:
> +		retval = alloc_enum_data();
> +		break;
> +	case INT:
> +		retval = alloc_int_data();
> +		break;
> +	case STR:
> +		retval = alloc_str_data();
> +		break;
> +	case PO:
> +		retval = alloc_po_data();
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return retval;
> +}
> +
> +/**
> + * destroy_attribute_objs() - Free a kset of kobjects
> + * @kset: The kset to destroy
> + *
> + * Fress kobjects created for each attribute_name under attribute type kset
> + **/
> +static void destroy_attribute_objs(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	mutex_lock(&kset_mutex);
> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> +		kobject_put(pos);
> +	}
> +	mutex_unlock(&kset_mutex);
> +}
> +
> +/**
> + * release_attributes_data() - Clean-up all sysfs directories and files created
> + **/
> +static void release_attributes_data(void)
> +{
> +	release_reset_bios_data();
> +
> +	exit_enum_attributes(main_dir_kset);
> +	exit_int_attributes(main_dir_kset);
> +	exit_str_attributes(main_dir_kset);
> +	exit_po_attributes(main_dir_kset);
> +
> +	if (main_dir_kset) {
> +		destroy_attribute_objs(main_dir_kset);
> +		kset_unregister(main_dir_kset);
> +	}

Why are the above 2 calls protected with a "if (main_dir_kset)" and the
other 4 calls, which also take main_dir_kset as an argument not ?

Can we ever get here with main_dir_kset == NULL ?

> +}
> +
> +/**
> + * init_bios_attributes() - Initialize all attributes for a type
> + * @attr_type: The attribute type to initialize
> + * @guid: The WMI GUID associated with this type to initialize
> + *
> + * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
> + * Populates each attrbute typ's respective properties under sysfs files
> + **/
> +static int init_bios_attributes(int attr_type, const char *guid)
> +{
> +	struct kobject *attr_name_kobj; //individual attribute names
> +	union acpi_object *obj = NULL;
> +	union acpi_object *elements;
> +	int instance_id = 0;
> +	int retval = 0;
> +
> +	retval = alloc_attributes_data(attr_type);
> +	if (retval)
> +		return retval;
> +	obj = get_wmiobj_pointer(instance_id, guid);
> +	if (!obj)
> +		return -ENODEV;
> +	elements = obj->package.elements;
> +
> +	while (elements) {
> +		/* sanity checking */
> +		if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
> +			dev_dbg(&platform_device->dev, "empty attribute found");
> +			goto nextobj;
> +		}
> +		if (kset_find_obj(main_dir_kset, elements[ATTR_NAME].string.pointer)) {
> +			dev_dbg(&platform_device->dev, "duplicate attribute name found - %s",
> +				elements[ATTR_NAME].string.pointer);
> +			goto nextobj;
> +		}
> +
> +		/* build attribute */
> +		attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> +		if (!attr_name_kobj)
> +			goto err_attr_init;
> +
> +		attr_name_kobj->kset = main_dir_kset;
> +
> +		retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
> +						elements[ATTR_NAME].string.pointer);
> +		if (retval) {
> +			kobject_put(attr_name_kobj);
> +			goto err_attr_init;
> +		}
> +
> +		/* enumerate all of this attribute */
> +		switch (attr_type) {
> +		case ENUM:
> +			retval = populate_enum_data(elements, instance_id, attr_name_kobj);
> +			break;
> +		case INT:
> +			retval = populate_int_data(elements, instance_id, attr_name_kobj);
> +			break;
> +		case STR:
> +			retval = populate_str_data(elements, instance_id, attr_name_kobj);
> +			break;
> +		case PO:
> +			retval = populate_po_data(elements, instance_id, attr_name_kobj);
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		if (retval) {
> +			dev_dbg(&platform_device->dev, "failed to populate %s",
> +				elements[ATTR_NAME].string.pointer);
> +			goto err_attr_init;
> +		}
> +
> +nextobj:
> +		kfree(obj);
> +		instance_id++;
> +		obj = get_wmiobj_pointer(instance_id, guid);
> +		elements = obj ? obj->package.elements : NULL;
> +	}
> +
> +	goto out;
> +
> +err_attr_init:
> +	release_attributes_data();
> +	kfree(obj);
> +out:
> +	return retval;
> +}
> +
> +static int __init init_dell_bios_attrib_wmi(void)
> +{
> +	int ret = 0;
> +
> +	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
> +	    !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
> +		pr_err("Unable to run on non-Dell system\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = init_dell_wmi_bios_attr_set_interface();
> +	if (ret || !wmi_priv.bios_attr_wdev) {
> +
> +		dev_dbg(&platform_device->dev, "failed to initialize set interface");
> +		goto fail_set_interface;
> +	}
> +
> +	ret = init_dell_wmi_bios_attr_pass_interface();
> +	if (ret || !wmi_priv.password_attr_wdev) {
> +		dev_dbg(&platform_device->dev, "failed to initialize pass interface");
> +		goto fail_pass_interface;
> +	}
> +
> +	ret = platform_driver_register(&platform_driver);
> +	if (ret)
> +		goto fail_platform_driver;
> +
> +	platform_device = platform_device_alloc(DRIVER_NAME, -1);
> +	if (!platform_device) {
> +		ret = -ENOMEM;
> +		goto fail_platform_device_alloc;
> +	}
> +
> +	ret = platform_device_add(platform_device);
> +	if (ret)
> +		goto fail_platform_device_add;
> +
> +	main_dir_kset = kset_create_and_add("attributes", NULL, &platform_device->dev.kobj);
> +	if (!main_dir_kset) {
> +		ret = -ENOMEM;
> +		goto fail_platform_device_add;
> +	}
> +
> +	ret = create_reset_bios();
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "could not create reset BIOS attribute");
> +		goto fail_kset;
> +	}
> +
> +	ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "failed to populate enumeration type attributes");
> +		goto fail_create_group;
> +	}
> +
> +	ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "failed to populate integer type attributes");
> +		goto fail_create_group;
> +	}
> +
> +	ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "failed to populate string type attributes");
> +		goto fail_create_group;
> +	}
> +
> +	ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> +	if (ret) {
> +		dev_dbg(&platform_device->dev, "failed to populate pass object type attributes");
> +		goto fail_create_group;
> +	}
> +
> +	return 0;
> +
> +fail_create_group:
> +	release_attributes_data();
> +	platform_device_del(platform_device);
> +
> +fail_kset:
> +	kset_unregister(main_dir_kset);
> +
> +fail_platform_device_add:
> +	platform_device_put(platform_device);
> +
> +fail_platform_device_alloc:
> +	platform_driver_unregister(&platform_driver);
> +
> +fail_platform_driver:
> +	exit_dell_wmi_bios_attr_pass_interface();
> +
> +fail_pass_interface:
> +	exit_dell_wmi_bios_attr_set_interface();
> +
> +fail_set_interface:
> +	return ret;
> +}
> +
> +static void __exit exit_dell_bios_attrib_wmi(void)
> +{
> +	release_attributes_data();
> +	exit_dell_wmi_bios_attr_set_interface();
> +	exit_dell_wmi_bios_attr_pass_interface();
> +	if (platform_device) {
> +		platform_device_unregister(platform_device);
> +		platform_driver_unregister(&platform_driver);
> +	}
> +}
> +
> +module_init(init_dell_bios_attrib_wmi);
> +module_exit(exit_dell_bios_attrib_wmi);
> +
> +MODULE_AUTHOR("Mario Limonciello <[e-mail]>");
> +MODULE_AUTHOR("Prasanth Ksr <[e-mail]>");
> +MODULE_AUTHOR("Divya Bharathi <[e-mail]>");
> +MODULE_DESCRIPTION("Dell platform setting control interface");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.h b/drivers/platform/x86/dell-wmi-sysman-attributes.h
> new file mode 100644
> index 000000000000..a12c03ab96c9
> --- /dev/null
> +++ b/drivers/platform/x86/dell-wmi-sysman-attributes.h
> @@ -0,0 +1,132 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + * Definitions for kernel modules using Dell WMI System Management Driver
> + *
> + *  Copyright (c) 2020 Dell Inc.
> + */
> +
> +#ifndef _DELL_WMI_BIOS_ATTR_H_
> +#define _DELL_WMI_BIOS_ATTR_H_
> +
> +#include <linux/wmi.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/capability.h>
> +
> +#define DRIVER_NAME					"dell-wmi-sysman"
> +#define MAX_BUFF  512
> +
> +#define DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID	"F1DDEE52-063C-4784-A11E-8A06684B9BF5"
> +#define DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID		"F1DDEE52-063C-4784-A11E-8A06684B9BFA"
> +#define DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID		"F1DDEE52-063C-4784-A11E-8A06684B9BF9"
> +#define DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID		"0894B8D6-44A6-4719-97D7-6AD24108BFD4"
> +#define DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID		"F1DDEE52-063C-4784-A11E-8A06684B9BF4"
> +#define DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID		"70FE8229-D03B-4214-A1C6-1F884B1A892A"
> +
> +struct dell_wmi_sysman_priv {
> +	char current_admin_password[MAX_BUFF];
> +	char current_system_password[MAX_BUFF];
> +	struct wmi_device *password_attr_wdev;
> +	struct wmi_device *bios_attr_wdev;
> +	bool pending_changes;
> +};
> +
> +enum { ENUM, INT, STR, PO };
> +
> +enum {
> +	ATTR_NAME,
> +	DISPL_NAME_LANG_CODE,
> +	DISPLAY_NAME,
> +	DEFAULT_VAL,
> +	CURRENT_VAL,
> +	MODIFIER
> +};
> +
> +#define get_instance_id(type)							\
> +int get_##type##_instance_id(struct kobject *kobj)				\
> +{										\
> +	int i;									\
> +	for (i = 0; i <= type##_instances_count; i++) {				\
> +		if (!(strcmp(kobj->name, type##_data[i].attribute_name)))	\
> +			return i;						\
> +	}									\
> +	return -EIO;								\
> +}
> +
> +#define attribute_s_property_show(name, type)					\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
> +			   char *buf)						\
> +{										\
> +	int i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		return sprintf(buf, "%s\n", type##_data[i].name);		\
> +	return 0;								\
> +}
> +
> +#define attribute_n_property_show(name, type)					\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
> +			   char *buf)						\
> +{										\
> +	int i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		return sprintf(buf, "%d\n", type##_data[i].name);		\
> +	return 0;								\
> +}
> +
> +#define attribute_property_store(curr_val, type)				\
> +static ssize_t curr_val##_store(struct kobject *kobj,				\
> +				struct kobj_attribute *attr,			\
> +				const char *buf, size_t count)			\
> +{										\
> +	char *p = memchr(buf, '\n', count);					\
> +	int ret = -EIO;								\
> +	int i;									\
> +										\
> +	if (p != NULL)								\
> +		*p = '\0';							\
> +	i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		ret = validate_##type##_input(i, buf);				\
> +	if (!ret)								\
> +		ret = set_attribute(kobj->name, buf);				\
> +	return ret ? ret : count;						\
> +}
> +
> +union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string);
> +int get_instance_count(const char *guid_string);
> +void strncpy_attr(char *dest, char *src);
> +
> +int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
> +			struct kobject *attr_name_kobj);
> +int alloc_enum_data(void);
> +void exit_enum_attributes(struct kset *kset);
> +
> +int populate_int_data(union acpi_object *integer_obj, int instance_id,
> +			struct kobject *attr_name_kobj);
> +int alloc_int_data(void);
> +void exit_int_attributes(struct kset *kset);
> +
> +int populate_str_data(union acpi_object *str_obj, int instance_id, struct kobject *attr_name_kobj);
> +int alloc_str_data(void);
> +void exit_str_attributes(struct kset *kset);
> +
> +int populate_po_data(union acpi_object *po_obj, int instance_id, struct kobject *attr_name_kobj);
> +int alloc_po_data(void);
> +void exit_po_attributes(struct kset *kset);
> +
> +int set_attribute(const char *a_name, const char *a_value);
> +int set_bios_defaults(u8 defType);
> +
> +void exit_dell_wmi_bios_attr_set_interface(void);
> +int init_dell_wmi_bios_attr_set_interface(void);
> +int map_wmi_error(int error_code);
> +size_t calculate_security_buffer(void);
> +void populate_security_buffer(char *buffer, char *authentication);
> +
> +int set_current_password(const char *password_type, const char *cur);
> +int set_new_password(const char *password_type, const char *new);
> +int init_dell_wmi_bios_attr_pass_interface(void);
> +void exit_dell_wmi_bios_attr_pass_interface(void);
> +
> +#endif
> 

Regards,

Hans

Limonciello, Mario Sept. 14, 2020, 5:12 p.m. UTC | #4

> 
> On 9/4/20 4:28 PM, Divya Bharathi wrote:
> > diff --git a/drivers/platform/x86/dell-wmi-biosattr-interface.c
> b/drivers/platform/x86/dell-wmi-biosattr-interface.c
> > new file mode 100644
> > index 000000000000..dda38d448fec
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-biosattr-interface.c
> > @@ -0,0 +1,198 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to SET methods under BIOS attributes interface
> GUID for use
> > + * with dell-wmi-sysman
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#include <linux/nls.h>
> > +#include <linux/wmi.h>
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +#define SETDEFAULTVALUES_METHOD_ID					0x02
> > +#define SETBIOSDEFAULTS_METHOD_ID					0x03
> > +#define SETATTRIBUTE_METHOD_ID						0x04
> > +
> > +static DEFINE_MUTEX(call_mutex);
> 
> By doing this you still declare one lock per file, so code from 2 files could
> be accessing the wmi_priv struct and be making WMI calls at the same time.
> 
> Please add a mutex to the dell_wmi_sysman_priv struct, like this:
> 
> In dell-wmi-sysman-attributes.h:
> 
> struct dell_wmi_sysman_priv {
> 	struct mutex mutex;
>          char current_admin_password[MAX_BUFF];
>          char current_system_password[MAX_BUFF];
>          struct wmi_device *password_attr_wdev;
>          struct wmi_device *bios_attr_wdev;
>          bool pending_changes;
> };
> 
> And in dell-wmi-sysman-attributes.c:
> 
> struct dell_wmi_sysman_priv wmi_priv = {
> 	.mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
> };
> 
> And then whenever you need the mutex call:
> 
> 	mutex_lock(&wmi_priv.mutex);
> 	...
> 	mutex_unlock(&wmi_priv.mutex);
> 
> And use this in all files.
> 
> > +extern struct dell_wmi_sysman_priv wmi_priv;
> 
> Please move this to dell-wmi-sysman-attributes.h .
> 

I guess locking it down to a single mutex will actually make it more determinant
if you tried to do two things at once.  We'll rework that again for v3.

> 
> > +
> > +static int call_biosattributes_interface(struct wmi_device *wdev, char
> *in_args, size_t size,
> > +					int method_id)
> > +{
> > +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> > +	struct acpi_buffer input;
> > +	union acpi_object *obj;
> > +	acpi_status status;
> > +	int ret = -EIO;
> > +
> > +	input.length =  (acpi_size) size;
> > +	input.pointer = in_args;
> > +	status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
> > +	if (ACPI_FAILURE(status))
> > +		return -EIO;
> > +	obj = (union acpi_object *)output.pointer;
> > +	if (obj->type == ACPI_TYPE_INTEGER)
> > +		ret = obj->integer.value;
> > +
> > +	kfree(output.pointer);
> > +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
> 
> Why are you generating an uevent here? I think this needs a comment (or it
> should be removed).

It's there so that userspace can know that a setting has been changed and doesn't
need to poll the attribute indicating a reboot is pending.

We can certainly add a comment to this effect.

> 
> > +	return map_wmi_error(ret);
> > +}
> > +
> > +/**
> > + * set_attribute() - Update an attribute value
> > + * @a_name: The attribute name
> > + * @a_value: The attribute value
> > + *
> > + * Sets an attribute to new value
> > + **/
> > +int set_attribute(const char *a_name, const char *a_value)
> > +{
> > +	size_t security_area_size, string_area_size, buffer_size;
> > +	char *attribute_name, *attribute_value;
> > +	u8 *name_len, *value_len;
> > +	char *buffer;
> > +	int ret;
> > +
> > +	/* build/calculate buffer */
> > +	security_area_size = calculate_security_buffer();
> > +	string_area_size = (strlen(a_name) + strlen(a_value))*2;
> > +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 2;
> > +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> > +	if (!buffer)
> > +		return -ENOMEM;
> > +
> > +	/* build security area */
> > +	if (strlen(wmi_priv.current_admin_password) > 0)
> > +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
> > +
> > +	/* build variables to set */
> > +	name_len = buffer + security_area_size;
> > +	attribute_name = name_len + sizeof(u16);
> > +	*name_len = utf8s_to_utf16s(a_name, strlen(a_name), UTF16_HOST_ENDIAN,
> > +				    (wchar_t *) attribute_name, MAX_BUFF) * 2;
> > +	if (*name_len < 0) {
> > +		ret = -EINVAL;
> > +		pr_err("UTF16 conversion failed");
> > +		goto out_set_attribute;
> > +	}
> > +
> > +	value_len = (u8 *) attribute_name + *name_len;
> > +	attribute_value = value_len + sizeof(u16);
> > +	*value_len = utf8s_to_utf16s(a_value, strlen(a_value),
> UTF16_HOST_ENDIAN,
> > +				    (wchar_t *) attribute_value, MAX_BUFF) * 2;
> > +	if (*value_len < 0) {
> > +		ret = -EINVAL;
> > +		pr_err("UTF16 conversion failed");
> > +		goto out_set_attribute;
> > +	}
> > +
> > +	mutex_lock(&call_mutex);
> > +	if (!wmi_priv.bios_attr_wdev) {
> > +		ret = -ENODEV;
> > +		pr_err("no WMI backend bound");
> > +		goto out_set_attribute;
> > +	}
> 
> It is probably better to move this to the top, as I mentioned in my reply
> to Mario, you could add something like this to the top of each function,
> even before allocating the buffer and filling it.

The placement was intentional to avoid taking the mutex until data was validated.
Is it preferable to make it specifically on entry into functions then?

> 
>      mutex_lock(&wmi_priv.mutex);
> 
>      if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
>          ret = -ENODEV;
>          goto out_set_attribute;
>      }
> 
> Note this requires that you initialize the buf pointer to NULL
> wehn declaring it.
> 
> Having this at the top of each function establishes a pattern where
> it easy for a reader of the code to:
> 
> a) See that the check is present when checking that the driver being
> unbound is checked everywhere
> 
> b) Ignore the check as "boilerplate" when looking at other parts of
> the code

I guess this argument makes sense - setting up a pattern is a good way
to spot the function that stands out when a coding mistake occurs.

> 
> Also note that I dropped the pr_err. Users should not go around and
> unbind drivers, if they then we should not crash. But the user asked
> for it, so just returning -ENODEV without logging an error should be
> fine.
> 
> 
> > +
> > +	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
> > +					    buffer, buffer_size,
> > +					    SETATTRIBUTE_METHOD_ID);
> > +	if (ret == -EOPNOTSUPP)
> > +		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be
> configured");
> > +	else if (ret == -EACCES)
> > +		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
> > +
> > +	wmi_priv.pending_changes = 1;
> > +out_set_attribute:
> > +	kfree(buffer);
> > +	mutex_unlock(&call_mutex);
> > +
> > +	return ret;
> > +}
> > +
> > +/**
> > + * set_bios_defaults() - Resets BIOS defaults
> > + * @deftype: the type of BIOS value reset to issue.
> > + *
> > + * Resets BIOS defaults
> > + **/
> > +int set_bios_defaults(u8 deftype)
> > +{
> > +	size_t security_area_size, buffer_size;
> > +	size_t integer_area_size = sizeof(u8);
> > +	u8 *defaultType;
> > +	char *buffer;
> > +	int ret;
> > +
> 
> You are missing the check for the driver being unbound here,
> this nicely documents why you should have this at the top
> of each function making WMI calls.

Yeah - true.

> 
> > +	security_area_size = calculate_security_buffer();
> > +	buffer_size = security_area_size + integer_area_size;
> > +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> > +	if (!buffer)
> > +		return -ENOMEM;
> > +
> > +	/* build security area */
> > +	if (strlen(wmi_priv.current_admin_password) > 0)
> > +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
> > +
> > +	mutex_lock(&call_mutex);
> > +	if (!wmi_priv.bios_attr_wdev) {
> > +		ret = -ENODEV;
> > +		pr_err("no WMI backend bound");
> > +		goto out_bios_defaults;
> > +	}
> > +
> > +	defaultType = buffer + security_area_size;
> > +	*defaultType = deftype;
> > +
> > +	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer,
> buffer_size,
> > +					    SETBIOSDEFAULTS_METHOD_ID);
> > +	if (ret)
> > +		dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed:
> %d", ret);
> > +	wmi_priv.pending_changes = 1;
> > +out_bios_defaults:
> > +	kfree(buffer);
> > +	mutex_unlock(&call_mutex);
> > +
> > +	return ret;
> > +}
> > +
> > +static int dell_wmi_bios_attr_set_interface_probe(struct wmi_device *wdev,
> const void *context)
> > +{
> > +	wmi_priv.bios_attr_wdev = wdev;
> > +	return 0;
> > +}
> > +
> > +static int dell_wmi_bios_attr_set_interface_remove(struct wmi_device *wdev)
> > +{
> > +	mutex_lock(&call_mutex);
> > +	wmi_priv.bios_attr_wdev = NULL;
> > +	mutex_unlock(&call_mutex);
> > +	return 0;
> > +}
> > +
> > +static const struct wmi_device_id
> dell_wmi_bios_attr_set_interface_id_table[] = {
> > +	{ .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
> > +	{ },
> > +};
> > +static struct wmi_driver dell_wmi_bios_attr_set_interface_driver = {
> > +	.driver = {
> > +		.name = DRIVER_NAME"-set"
> > +	},
> > +	.probe = dell_wmi_bios_attr_set_interface_probe,
> > +	.remove = dell_wmi_bios_attr_set_interface_remove,
> > +	.id_table = dell_wmi_bios_attr_set_interface_id_table,
> > +};
> > +
> > +int init_dell_wmi_bios_attr_set_interface(void)
> > +{
> > +	return wmi_driver_register(&dell_wmi_bios_attr_set_interface_driver);
> > +}
> > +
> > +void exit_dell_wmi_bios_attr_set_interface(void)
> > +{
> > +	wmi_driver_unregister(&dell_wmi_bios_attr_set_interface_driver);
> > +}
> > +
> > +MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_set_interface_id_table);
> > diff --git a/drivers/platform/x86/dell-wmi-enum-attributes.c
> b/drivers/platform/x86/dell-wmi-enum-attributes.c
> > new file mode 100644
> > index 000000000000..f2370f067b6d
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-enum-attributes.c
> > @@ -0,0 +1,214 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to enumeration type attributes under BIOS
> Enumeration GUID for use
> > + * with dell-wmi-sysman
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +static DEFINE_MUTEX(enum_mutex);
> > +extern struct mutex kset_mutex;
> 
> Please just use the global wmi_priv.mutex to replace both of these.

Ack

> 
> > +
> > +/* kept variable names same as in sysfs file name for sysfs_show macro
> definition */
> > +struct enumeration_data {
> > +	char display_name_language_code[MAX_BUFF];
> > +	char attribute_name[MAX_BUFF];
> > +	char display_name[MAX_BUFF];
> > +	char default_value[MAX_BUFF];
> > +	char current_value[MAX_BUFF];
> > +	char modifier[MAX_BUFF];
> > +	int value_modifier_count;
> > +	char value_modifier[MAX_BUFF];
> > +	int possible_value_count;
> > +	char possible_value[MAX_BUFF];
> > +	char type[MAX_BUFF];
> > +};
> > +
> > +static struct enumeration_data *enumeration_data;
> > +static int enumeration_instances_count;
> 
> Please store these 2 in the global wmi_priv data.
> 
> Also there is a lot of overlap between structs like
> struct enumeration_data, struct integer_data, etc.
> 
> I think it would be good to make a single struct
> attr_data, which contains fields for all the
> supported types.
> 
> I also see a lot of overlapping code between:
> 
> drivers/platform/x86/dell-wmi-enum-attributes.c
> drivers/platform/x86/dell-wmi-int-attributes.c
> drivers/platform/x86/dell-wmi-string-attributes.c
> 
> I think that folding the data structures together
> will help with also unifying that code into a
> single dell-wmi-std-attributes.c file.
> 
> > +get_instance_id(enumeration);
> > +
> > +static ssize_t current_value_show(struct kobject *kobj, struct
> kobj_attribute *attr, char *buf)
> > +{
> > +	int instance_id;
> > +
> > +	if (!capable(CAP_SYS_ADMIN))
> > +		return -EPERM;
> > +	instance_id = get_enumeration_instance_id(kobj);
> 
> If you unify the integer, string and enum code then this just becomes:
> get_std_instance_id(kobj)
> 
> > +	if (instance_id >= 0) {
> > +		union acpi_object *obj;
> > +
> > +		obj = get_wmiobj_pointer(instance_id,
> DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> > +		if (!obj)
> > +			return -AE_ERROR;
> 
> > +		strncpy_attr(enumeration_data[instance_id].current_value,
> > +		       obj->package.elements[CURRENT_VAL].string.pointer);
> So these 2 lines seem to be the only thing which is different for
> current_value_show,
> between enums, ints and strings, so you can put a simple switch-case on the
> type here.
> 

This is a good point, it will cause a lot of changes as a result and a lot less
code.

> > +		kfree(obj);
> > +		return sprintf(buf, "%s\n",
> enumeration_data[instance_id].current_value);
> > +	}
> > +	return -EIO;
> > +} > +
> > +/**
> > + * validate_enumeration_input() - Validate input of current_value against
> possible values
> > + * @instance_id: The instance on which input is validated
> > + * @buf: Input value
> > + **/
> > +int validate_enumeration_input(int instance_id, const char *buf)
> > +{
> > +	char *options, *tmp, *p;
> > +	int ret = -EINVAL;
> > +
> > +	options = tmp = kstrdup((enumeration_data[instance_id].possible_value),
> GFP_KERNEL);
> > +	if (!options)
> > +		return -ENOMEM;
> > +
> > +	while ((p = strsep(&options, ";")) != NULL) {
> > +		if (!*p)
> > +			continue;
> > +		if (!strncasecmp(p, buf, strlen(p))) {
> > +			ret = 0;
> > +			break;
> > +		}
> > +	}
> > +
> > +	kfree(tmp);
> > +	return ret;
> > +}
> 
> For the validate functions you can keep all 3 in the new
> dell-wmi-std-attributes.c file and then call the right one through a
> switch-case based on the type.
> 
> > +
> > +attribute_s_property_show(display_name_language_code, enumeration);
> > +static struct kobj_attribute displ_langcode =
> > +		__ATTR_RO(display_name_language_code);
> > +
> > +attribute_s_property_show(display_name, enumeration);
> > +struct kobj_attribute displ_name =
> > +		__ATTR_RO(display_name);
> > +
> > +attribute_s_property_show(default_value, enumeration);
> > +struct kobj_attribute default_val =
> > +		__ATTR_RO(default_value);
> > +
> > +attribute_property_store(current_value, enumeration);
> > +struct kobj_attribute current_val =
> > +		__ATTR_RW(current_value);
> > +
> > +attribute_s_property_show(modifier, enumeration);
> > +struct kobj_attribute modifier =
> > +		__ATTR_RO(modifier);
> > +
> > +attribute_s_property_show(value_modifier, enumeration);
> > +struct kobj_attribute value_modfr =
> > +		__ATTR_RO(value_modifier);
> > +
> > +attribute_s_property_show(possible_value, enumeration);
> > +struct kobj_attribute poss_val =
> > +		__ATTR_RO(possible_value);
> > +
> > +attribute_s_property_show(type, enumeration);
> > +struct kobj_attribute type =
> > +		__ATTR_RO(type);
> > +
> > +static struct attribute *enumeration_attrs[] = {
> > +	&displ_langcode.attr,
> > +	&displ_name.attr,
> > +	&default_val.attr,
> > +	&current_val.attr,
> > +	&modifier.attr,
> > +	&value_modfr.attr,
> > +	&poss_val.attr,
> > +	&type.attr,
> > +	NULL,
> > +};
> > +
> > +static const struct attribute_group enumeration_attr_group = {
> > +	.attrs = enumeration_attrs,
> > +};
> > +
> > +int alloc_enum_data(void)
> > +{
> > +	int ret = 0;
> > +
> > +	enumeration_instances_count =
> get_instance_count(DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> > +	enumeration_data = kzalloc((sizeof(struct enumeration_data) *
> enumeration_instances_count),
> > +					GFP_KERNEL);
> > +	if (!enumeration_data)
> > +		ret = -ENOMEM;
> > +	return ret;
> > +}
> > +
> 
> The rest of the file is mostly identical between strings, ints and enums.
> 
> > +/**
> > + * populate_enum_data() - Populate all properties of an instance under
> enumeration attribute
> > + * @enumeration_obj: ACPI object with enumeration data
> > + * @instance_id: The instance to enumerate
> > + * @attr_name_kobj: The parent kernel object
> > + **/
> > +int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
> > +			struct kobject *attr_name_kobj)
> > +{
> > +	int retval = sysfs_create_group(attr_name_kobj,
> &enumeration_attr_group);
> > +	int i, next_obj;
> > +
> > +	if (retval)
> > +		goto out;
> > +
> > +	mutex_lock(&enum_mutex);
> > +	strncpy_attr(enumeration_data[instance_id].attribute_name,
> > +		enumeration_obj[ATTR_NAME].string.pointer);
> > +	strncpy_attr(enumeration_data[instance_id].display_name_language_code,
> > +		enumeration_obj[DISPL_NAME_LANG_CODE].string.pointer);
> > +	strncpy_attr(enumeration_data[instance_id].display_name,
> > +		enumeration_obj[DISPLAY_NAME].string.pointer);
> > +	strncpy_attr(enumeration_data[instance_id].default_value,
> > +		enumeration_obj[DEFAULT_VAL].string.pointer);
> > +	strncpy_attr(enumeration_data[instance_id].current_value,
> > +		enumeration_obj[CURRENT_VAL].string.pointer);
> > +	strncpy_attr(enumeration_data[instance_id].modifier,
> > +		enumeration_obj[MODIFIER].string.pointer);
> > +
> > +	next_obj = MODIFIER + 1;
> > +
> > +	enumeration_data[instance_id].value_modifier_count =
> > +		(uintptr_t)enumeration_obj[next_obj].string.pointer;
> > +
> > +	for (i = 0; i < enumeration_data[instance_id].value_modifier_count; i++)
> {
> > +		strcat(enumeration_data[instance_id].value_modifier,
> > +			enumeration_obj[++next_obj].string.pointer);
> > +		strcat(enumeration_data[instance_id].value_modifier, ";");
> > +	}
> > +
> > +	enumeration_data[instance_id].possible_value_count =
> > +		(uintptr_t) enumeration_obj[++next_obj].string.pointer;
> > +
> > +	for (i = 0; i < enumeration_data[instance_id].possible_value_count; i++)
> {
> > +		strcat(enumeration_data[instance_id].possible_value,
> > +			enumeration_obj[++next_obj].string.pointer);
> > +		strcat(enumeration_data[instance_id].possible_value, ";");
> > +	}
> > +	strncpy_attr(enumeration_data[instance_id].type, "enumeration");
> > +	mutex_unlock(&enum_mutex);
> > +
> > +out:
> > +	return retval;
> > +}
> 
> 
> I guess you may also need a switch-case based on the
> type in the populare function.
> 
> > +
> > +/**
> > + * exit_enum_attributes() - Clear all attribute data
> > + * @kset: The kset to free
> > + *
> > + * Clears all data allocated for this group of attributes
> > + **/
> > +void exit_enum_attributes(struct kset *kset)
> > +{
> > +	struct kobject *pos, *next;
> > +
> > +	mutex_lock(&kset_mutex);
> > +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> > +		sysfs_remove_group(pos, &enumeration_attr_group);
> > +	}
> > +	mutex_unlock(&kset_mutex);
> > +	mutex_lock(&enum_mutex);
> > +	kfree(enumeration_data);
> > +	mutex_unlock(&enum_mutex);
> > +}
> 
> Since there is now only 1 kset for the main dir, you are now
> calling sysfs_remove_group 4 times (for all the different times)
> on each entry in the attributes dir. I guess this may fail silently,
> but it still is not good. So this needs to be fixed.
> 
> The remarks to this file also apply to the:
> 
> drivers/platform/x86/dell-wmi-int-attributes.c
> drivers/platform/x86/dell-wmi-string-attributes.c
> 
> files.
> 
> > diff --git a/drivers/platform/x86/dell-wmi-int-attributes.c
> b/drivers/platform/x86/dell-wmi-int-attributes.c
> > new file mode 100644
> > index 000000000000..d922d4f73ce9
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-int-attributes.c
> > @@ -0,0 +1,195 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to integer type attributes under BIOS Integer
> GUID for use with
> > + * dell-wmi-sysman
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +static DEFINE_MUTEX(int_mutex);
> > +extern struct mutex kset_mutex;
> > +
> > +enum int_properties {LOWER_BOUND = 6, UPPER_BOUND, SCALAR_INCR};
> > +
> > +/* kept variable names same as in sysfs file name for sysfs_show macro
> definition */
> > +struct integer_data {
> > +	char display_name_language_code[MAX_BUFF];
> > +	char attribute_name[MAX_BUFF];
> > +	char display_name[MAX_BUFF];
> > +	int default_value;
> > +	int current_value;
> > +	char modifier[MAX_BUFF];
> > +	int lower_bound;
> > +	int upper_bound;
> > +	int scalar_increment;
> > +	char type[MAX_BUFF];
> > +};
> > +
> > +static struct integer_data *integer_data;
> > +static int integer_instances_count;
> > +get_instance_id(integer);
> > +
> > +static ssize_t current_value_show(struct kobject *kobj, struct
> kobj_attribute *attr, char *buf)
> > +{
> > +	int instance_id;
> > +
> > +	if (!capable(CAP_SYS_ADMIN))
> > +		return -EPERM;
> > +	instance_id = get_integer_instance_id(kobj);
> > +	if (instance_id >= 0) {
> > +		union acpi_object *obj;
> > +
> > +		obj = get_wmiobj_pointer(instance_id,
> DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> > +		if (!obj)
> > +			return -AE_ERROR > +
> 	integer_data[instance_id].current_value =
> > +			(uintptr_t)obj->package.elements[CURRENT_VAL].string.pointer;
> > +		kfree(obj);
> > +		return sprintf(buf, "%d\n",
> integer_data[instance_id].current_value);
> > +	}
> > +	return -EIO;
> > +} > +
> > +/**
> > + * 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
> > + **/
> > +int validate_integer_input(int instance_id, const char *buf)
> > +{
> > +	int ret = -EINVAL;
> > +	int in_val;
> > +
> > +	if (kstrtoint(buf, 0, &in_val))
> > +		return ret;
> > +	if ((in_val >= integer_data[instance_id].lower_bound) &&
> > +	(in_val <= integer_data[instance_id].upper_bound))
> > +		ret = 0;
> > +
> > +	return ret;
> > +}
> > +
> > +attribute_s_property_show(display_name_language_code, integer);
> > +static struct kobj_attribute integer_displ_langcode =
> > +	__ATTR_RO(display_name_language_code);
> > +
> > +attribute_s_property_show(display_name, integer);
> > +struct kobj_attribute integer_displ_name =
> > +	__ATTR_RO(display_name);
> > +
> > +attribute_n_property_show(default_value, integer);
> > +struct kobj_attribute integer_default_val =
> > +	__ATTR_RO(default_value);
> > +
> > +attribute_property_store(current_value, integer);
> > +struct kobj_attribute integer_current_val =
> > +	__ATTR_RW(current_value);
> > +
> > +attribute_s_property_show(modifier, integer);
> > +struct kobj_attribute integer_modifier =
> > +	__ATTR_RO(modifier);
> > +
> > +attribute_n_property_show(lower_bound, integer);
> > +struct kobj_attribute integer_lower_bound =
> > +	__ATTR_RO(lower_bound);
> > +
> > +attribute_n_property_show(upper_bound, integer);
> > +struct kobj_attribute integer_upper_bound =
> > +	__ATTR_RO(upper_bound);
> > +
> > +attribute_n_property_show(scalar_increment, integer);
> > +struct kobj_attribute integer_scalar_increment =
> > +	__ATTR_RO(scalar_increment);
> > +
> > +attribute_s_property_show(type, integer);
> > +struct kobj_attribute integer_type =
> > +	__ATTR_RO(type);
> > +
> > +static struct attribute *integer_attrs[] = {
> > +	&integer_displ_langcode.attr,
> > +	&integer_displ_name.attr,
> > +	&integer_default_val.attr,
> > +	&integer_current_val.attr,
> > +	&integer_modifier.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 alloc_int_data(void)
> > +{
> > +	int ret = 0;
> > +
> > +	integer_instances_count =
> get_instance_count(DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> > +	integer_data = kzalloc((sizeof(struct integer_data) *
> integer_instances_count), GFP_KERNEL);
> > +	if (!integer_data)
> > +		ret = -ENOMEM;
> > +	return ret;
> > +}
> > +
> > +/**
> > + * populate_enum_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 populate_int_data(union acpi_object *integer_obj, int instance_id,
> > +			struct kobject *attr_name_kobj)
> > +{
> > +	int retval = sysfs_create_group(attr_name_kobj, &integer_attr_group);
> > +
> > +	if (retval)
> > +		goto out;
> > +
> > +	mutex_lock(&int_mutex);
> > +	strncpy_attr(integer_data[instance_id].attribute_name,
> > +		integer_obj[ATTR_NAME].string.pointer);
> > +	strncpy_attr(integer_data[instance_id].display_name_language_code,
> > +		integer_obj[DISPL_NAME_LANG_CODE].string.pointer);
> > +	strncpy_attr(integer_data[instance_id].display_name,
> > +		integer_obj[DISPLAY_NAME].string.pointer);
> > +	integer_data[instance_id].default_value =
> > +		(uintptr_t)integer_obj[DEFAULT_VAL].string.pointer;
> > +	integer_data[instance_id].current_value =
> > +		(uintptr_t)integer_obj[CURRENT_VAL].string.pointer;
> > +	strncpy_attr(integer_data[instance_id].modifier,
> integer_obj[MODIFIER].string.pointer);
> > +	integer_data[instance_id].lower_bound =
> > +		(uintptr_t)integer_obj[LOWER_BOUND].string.pointer;
> > +	integer_data[instance_id].upper_bound =
> > +		(uintptr_t)integer_obj[UPPER_BOUND].string.pointer;
> > +	integer_data[instance_id].scalar_increment =
> > +		(uintptr_t)integer_obj[SCALAR_INCR].string.pointer;
> > +	strncpy_attr(integer_data[instance_id].type, "integer");
> > +	mutex_unlock(&int_mutex);
> > +
> > +out:
> > +	return retval;
> > +}
> > +
> > +/**
> > + * exit_int_attributes() - Clear all attribute data
> > + * @kset: The kset to free
> > + *
> > + * Clears all data allocated for this group of attributes
> > + **/
> > +void exit_int_attributes(struct kset *kset)
> > +{
> > +	struct kobject *pos, *next;
> > +
> > +	mutex_lock(&kset_mutex);
> > +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> > +		sysfs_remove_group(pos, &integer_attr_group);
> > +	}
> > +	mutex_unlock(&kset_mutex);
> > +	mutex_lock(&int_mutex);
> > +	kfree(integer_data);
> > +	mutex_unlock(&int_mutex);
> > +}
> > diff --git a/drivers/platform/x86/dell-wmi-passobj-attributes.c
> b/drivers/platform/x86/dell-wmi-passobj-attributes.c
> > new file mode 100644
> > index 000000000000..87bb7772bb18
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-passobj-attributes.c
> > @@ -0,0 +1,168 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to password object type attributes under BIOS
> Password Object GUID for
> > + * use with dell-wmi-sysman
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +static DEFINE_MUTEX(po_mutex);
> > +extern struct mutex kset_mutex;
> > +
> > +enum po_properties {IS_PASS_SET = 1, MIN_PASS_LEN, MAX_PASS_LEN};
> > +
> > +/* kept variable names same as in sysfs file name for sysfs_show macro
> definition */
> > +struct po_data {
> > +	char attribute_name[MAX_BUFF];
> > +	int is_password_set;
> > +	int min_password_length;
> > +	int max_password_length;
> > +	char type[MAX_BUFF];
> > +};
> > +
> > +static struct po_data *po_data;
> > +static int po_instances_count;
> > +get_instance_id(po);
> > +
> > +static ssize_t is_password_set_show(struct kobject *kobj, struct
> kobj_attribute *attr, char *buf)
> > +{
> > +	int instance_id = get_po_instance_id(kobj);
> > +
> > +	if (instance_id >= 0) {
> > +		union acpi_object *obj;
> > +
> > +		obj = get_wmiobj_pointer(instance_id,
> DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> > +		if (!obj)
> > +			return -AE_ERROR;
> > +		po_data[instance_id].is_password_set =
> > +			(uintptr_t)obj->package.elements[IS_PASS_SET].string.pointer;
> > +		kfree(obj);
> > +		return sprintf(buf, "%d\n", po_data[instance_id].is_password_set);
> > +	}
> > +	return -EIO;
> > +}
> > +
> > +struct kobj_attribute po_is_pass_set =
> > +		__ATTR_RO(is_password_set);
> > +
> > +static ssize_t current_password_store(struct kobject *kobj,
> > +				      struct kobj_attribute *attr,
> > +				      const char *buf, size_t count)
> > +{
> > +	char *p = memchr(buf, '\n', count);
> > +	int ret;
> > +
> > +	if (p != NULL)
> > +		*p = '\0';
> > +	if (strlen(buf) > MAX_BUFF)
> > +		return -EINVAL;
> > +
> > +	ret = set_current_password(kobj->name, buf);
> > +	return ret ? ret : count;
> > +}
> > +
> > +struct kobj_attribute po_current_password =
> > +		__ATTR_WO(current_password);
> > +
> > +static ssize_t new_password_store(struct kobject *kobj,
> > +				  struct kobj_attribute *attr,
> > +				  const char *buf, size_t count)
> > +{
> > +	char *p = memchr(buf, '\n', count);
> > +	int ret;
> > +
> > +	if (p != NULL)
> > +		*p = '\0';
> > +	if (strlen(buf) > MAX_BUFF)
> > +		return -EINVAL;
> > +
> > +	ret = set_new_password(kobj->name, buf);
> > +	return ret ? ret : count;
> > +}
> > +
> > +struct kobj_attribute po_new_password =
> > +		__ATTR_WO(new_password);
> > +
> > +attribute_n_property_show(min_password_length, po);
> > +struct kobj_attribute po_min_pass_length =
> > +		__ATTR_RO(min_password_length);
> > +
> > +attribute_n_property_show(max_password_length, po);
> > +struct kobj_attribute po_max_pass_length =
> > +		__ATTR_RO(max_password_length);
> > +
> > +attribute_s_property_show(type, po);
> > +struct kobj_attribute po_type =
> > +	__ATTR_RO(type);
> > +
> > +static struct attribute *po_attrs[] = {
> > +	&po_is_pass_set.attr,
> > +	&po_min_pass_length.attr,
> > +	&po_max_pass_length.attr,
> > +	&po_current_password.attr,
> > +	&po_new_password.attr,
> > +	&po_type.attr,
> > +	NULL,
> > +};
> 
> So these don't have a current_value, display_name, etc. standard sysfs
> entries,
> so maybe put the passwords in a separate:
> /sys/devices/platform/dell-wmi-sysman/passwords
> 
> Dir, otherwise saying that all attributes have a current_value, display_name,
> etc.
> in the sysfs ABI documentation is incorrect. Doing this also gives you 2 dirs
> / ksets
> for the cleanup, 1 for all std attributes and 1 for passwords which also
> solves
> the cleanup problem I pointed out above.
> 
> Having 2 dirs, 1 for normal attributes and 1 for passwords, also matches the
> 2 WMI interfaces, so I believe that this is the right way to go.
> 
> 
> > +
> > +static const struct attribute_group po_attr_group = {
> > +	.attrs = po_attrs,
> > +};
> > +
> > +int alloc_po_data(void)
> > +{
> > +	int ret = 0;
> > +
> > +	po_instances_count =
> get_instance_count(DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> > +	po_data = kzalloc((sizeof(struct po_data) * po_instances_count),
> GFP_KERNEL);
> > +	if (!po_data)
> > +		ret = -ENOMEM;
> > +	return ret;
> > +}
> > +
> > +/**
> > + * populate_po_data() - Populate all properties of an instance under
> password object attribute
> > + * @po_obj: ACPI object with password object data
> > + * @instance_id: The instance to enumerate
> > + * @attr_name_kobj: The parent kernel object
> > + **/
> > +int populate_po_data(union acpi_object *po_obj, int instance_id, struct
> kobject *attr_name_kobj)
> > +{
> > +	int retval = sysfs_create_group(attr_name_kobj, &po_attr_group);
> > +
> > +	if (retval)
> > +		goto out;
> > +
> > +	mutex_lock(&po_mutex);
> > +	strncpy_attr(po_data[instance_id].attribute_name,
> po_obj[ATTR_NAME].string.pointer);
> > +	po_data[instance_id].is_password_set =
> (uintptr_t)po_obj[IS_PASS_SET].string.pointer;
> > +	po_data[instance_id].min_password_length =
> (uintptr_t)po_obj[MIN_PASS_LEN].string.pointer;
> > +	po_data[instance_id].max_password_length = (uintptr_t)
> po_obj[MAX_PASS_LEN].string.pointer;
> > +	strncpy_attr(po_data[instance_id].type, "password_object");
> > +	mutex_unlock(&po_mutex);
> > +
> > +out:
> > +	return retval;
> > +}
> > +
> > +/**
> > + * exit_po_attributes() - Clear all attribute data
> > + * @kset: The kset to free
> > + *
> > + * Clears all data allocated for this group of attributes
> > + **/
> > +void exit_po_attributes(struct kset *kset)
> > +{
> > +	struct kobject *pos, *next;
> > +
> > +	mutex_lock(&kset_mutex);
> > +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> > +		sysfs_remove_group(pos, &po_attr_group);
> > +	}
> > +	mutex_unlock(&kset_mutex);
> > +	mutex_lock(&po_mutex);
> > +	kfree(po_data);
> > +	mutex_unlock(&po_mutex);
> > +}
> > diff --git a/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> > new file mode 100644
> > index 000000000000..d105608cbb86
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
> > @@ -0,0 +1,200 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to SET password methods under BIOS attributes
> interface GUID
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#include <linux/nls.h>
> > +#include <linux/wmi.h>
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +static DEFINE_MUTEX(call_mutex);
> > +extern struct dell_wmi_sysman_priv wmi_priv;
> 
> See my comments on drivers/platform/x86/dell-wmi-biosattr-interface.c about
> this.
> 
> > +
> > +static int call_password_interface(struct wmi_device *wdev, char *in_args,
> size_t size)
> > +{
> > +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> > +	struct acpi_buffer input;
> > +	union acpi_object *obj;
> > +	acpi_status status;
> > +	int ret = -EIO;
> > +
> > +	input.length =  (acpi_size) size;
> > +	input.pointer = in_args;
> > +	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
> > +	if (ACPI_FAILURE(status))
> > +		return -EIO;
> > +	obj = (union acpi_object *)output.pointer;
> > +	if (obj->type == ACPI_TYPE_INTEGER)
> > +		ret = obj->integer.value;
> > +
> > +	kfree(output.pointer);
> > +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
> > +	return map_wmi_error(ret);
> > +}
> > +
> > +/**
> > + * get_current_password() - Get the current stored password value
> > + * @password_type: The type of password to store
> > + **/
> > +static char *get_current_password(const char *password_type)
> > +{
> > +	if (strcmp(password_type, "Admin") == 0)
> > +		return wmi_priv.current_admin_password;
> > +	if (strcmp(password_type, "System") == 0)
> > +		return wmi_priv.current_system_password;
> > +	dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s",
> password_type);
> > +	return NULL;
> > +}
> 
> Since you have the passwords directly available in wmi_priv now this
> function seems no longer necessary ?

Yeah I guess that's right.

> 
> > +
> > +/**
> > + * set_current_password() - Store current password
> > + * @password_type: The type of password to store
> > + * @current: The current value
> > + *
> > + * Sets the current value of the password.
> > + * This is used for:
> > + *  - Resetting password
> > + *  - Basis for any functions requiring password to execute
> > + **/
> > +int set_current_password(const char *password_type, const char *cur)
> > +{
> > +	char *current_password = get_current_password(password_type);
> > +
> > +	if (!current_password)
> > +		return -ENODEV;
> > +	strncpy(current_password, cur, (strlen(cur) + 1));
> > +	return 0;
> > +}
> 
> Same.
> 
> > +
> > +/**
> > + * set_new_password() - Sets a system admin password
> > + * @password_type: The type of password to set
> > + * @new: The new password
> > + *
> > + * Sets the password using plaintext interface
> > + **/
> > +int set_new_password(const char *password_type, const char *new)
> > +{
> > +	char *current_password, *type_value, *old_value, *new_value;
> > +	size_t security_area_size, string_area_size, buffer_size;
> > +	u8 *type_len, *old_len, *new_len;
> > +	char *buffer;
> > +	int ret;
> > +
> > +	/* only allow one password set at a time */
> 
> This comment is somewhat confusing, I guess it is meant for the
> mutex_lock call, but the mutex e.g. also protects wmi_priv.password_attr_wdev
> from changing while this code is running, please drop the comment.
> 
> > +	mutex_lock(&call_mutex);
> > +	if (!wmi_priv.password_attr_wdev) {
> > +		ret = -ENODEV;
> > +		pr_err("no WMI backend bound");
> > +		goto out_close_mutex;
> > +	}
> > +	current_password = get_current_password(password_type);
> > +	if (!current_password) {
> > +		ret = -ENODEV;
> > +		goto out_close_mutex;
> > +	}
> > +
> > +	/* build/calculate buffer */
> > +	security_area_size = calculate_security_buffer();
> > +	string_area_size = (strlen(password_type) + strlen(current_password) +
> strlen(new))*2;
> > +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 3;
> > +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> > +	if (!buffer) {
> > +		ret = -ENOMEM;
> > +		goto out_close_mutex;
> > +	}
> > +
> > +	/* build security area */
> > +	if (strlen(current_password) > 0)
> > +		populate_security_buffer(buffer, current_password);
> > +
> > +	/* build variables to set */
> > +	type_len = buffer + security_area_size;
> > +	type_value = type_len + sizeof(u16);
> > +	*type_len = utf8s_to_utf16s(password_type, strlen(password_type),
> UTF16_HOST_ENDIAN,
> > +				    (wchar_t *) type_value, MAX_BUFF) * 2;
> > +	if (*type_len < 0) {
> > +		ret = -EINVAL;
> > +		pr_err("UTF16 conversion failed");
> > +		goto out_cleanup;
> > +	}
> > +
> > +	old_len = type_value + *type_len;
> > +	old_value = old_len + sizeof(u16);
> > +	*old_len = utf8s_to_utf16s(current_password, strlen(current_password),
> UTF16_HOST_ENDIAN,
> > +				   (wchar_t *) old_value, MAX_BUFF) * 2;
> > +	if (*old_len < 0) {
> > +		ret = -EINVAL;
> > +		pr_err("UTF16 conversion failed");
> > +		goto out_cleanup;
> > +	}
> > +
> > +	new_len = old_value + *old_len;
> > +	new_value = new_len + sizeof(u16);
> > +	*new_len = utf8s_to_utf16s(new, strlen(new), UTF16_HOST_ENDIAN,
> > +				   (wchar_t *) new_value, MAX_BUFF) * 2;
> > +	if (*new_len < 0) {
> > +		ret = -EINVAL;
> > +		pr_err("UTF16 conversion failed");
> > +		goto out_cleanup;
> > +	}
> > +
> > +	ret = call_password_interface(wmi_priv.password_attr_wdev, buffer,
> buffer_size);
> > +	/* update current password so commands work after reset */
> > +	if (!ret)
> > +		ret = set_current_password(password_type, new);
> > +	/* explain to user the detailed failure reason */
> > +	else if (ret == -EOPNOTSUPP)
> > +		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be
> configured");
> > +	else if (ret == -EACCES)
> > +		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
> > +
> > +out_cleanup:
> > +	kfree(buffer);
> > +
> > +out_close_mutex:
> > +	mutex_unlock(&call_mutex);
> 
> You don't need 2 separate out_foo labels, kfree(NULL) is a no-op, so
> if you initialize buffer to NULL when you declare it you can use a single
> out label.
> 
> > +
> > +	return ret;
> > +}
> > +
> > +static int dell_wmi_bios_attr_pass_interface_probe(struct wmi_device *wdev,
> const void *context)
> > +{
> > +	wmi_priv.password_attr_wdev = wdev;
> > +	return 0;
> > +}
> > +
> > +static int dell_wmi_bios_attr_pass_interface_remove(struct wmi_device
> *wdev)
> > +{
> > +	mutex_lock(&call_mutex);
> > +	wmi_priv.password_attr_wdev = NULL;
> > +	mutex_unlock(&call_mutex);
> > +	return 0;
> > +}
> > +
> > +static const struct wmi_device_id
> dell_wmi_bios_attr_pass_interface_id_table[] = {
> > +	{ .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
> > +	{ },
> > +};
> > +static struct wmi_driver dell_wmi_bios_attr_pass_interface_driver = {
> > +	.driver = {
> > +		.name = DRIVER_NAME"-password"
> > +	},
> > +	.probe = dell_wmi_bios_attr_pass_interface_probe,
> > +	.remove = dell_wmi_bios_attr_pass_interface_remove,
> > +	.id_table = dell_wmi_bios_attr_pass_interface_id_table,
> > +};
> > +
> > +int init_dell_wmi_bios_attr_pass_interface(void)
> > +{
> > +	return wmi_driver_register(&dell_wmi_bios_attr_pass_interface_driver);
> > +}
> > +
> > +void exit_dell_wmi_bios_attr_pass_interface(void)
> > +{
> > +	wmi_driver_unregister(&dell_wmi_bios_attr_pass_interface_driver);
> > +}
> > +
> > +MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_pass_interface_id_table);
> > diff --git a/drivers/platform/x86/dell-wmi-string-attributes.c
> b/drivers/platform/x86/dell-wmi-string-attributes.c
> > new file mode 100644
> > index 000000000000..397de6fb13a3
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-string-attributes.c
> > @@ -0,0 +1,177 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to string type attributes under BIOS String GUID
> for use with
> > + * dell-wmi-sysman
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +static DEFINE_MUTEX(str_mutex);
> > +extern struct mutex kset_mutex;
> > +
> > +enum string_properties {MIN_LEN = 6, MAX_LEN};
> > +
> > +/* kept variable names same as in sysfs file name for sysfs_show macro
> definition */
> > +struct str_data {
> > +	char display_name_language_code[MAX_BUFF];
> > +	char attribute_name[MAX_BUFF];
> > +	char display_name[MAX_BUFF];
> > +	char default_value[MAX_BUFF];
> > +	char current_value[MAX_BUFF];
> > +	char modifier[MAX_BUFF];
> > +	int min_length;
> > +	int max_length;
> > +	char type[MAX_BUFF];
> > +};
> > +
> > +static struct str_data *str_data;
> > +static int str_instances_count;
> > +get_instance_id(str);
> > +
> > +static ssize_t current_value_show(struct kobject *kobj, struct
> kobj_attribute *attr, char *buf)
> > +{
> > +	int instance_id;
> > +
> > +	if (!capable(CAP_SYS_ADMIN))
> > +		return -EPERM;
> > +	instance_id = get_str_instance_id(kobj);
> > +	if (instance_id >= 0) {
> > +		union acpi_object *obj;
> > +
> > +		obj = get_wmiobj_pointer(instance_id,
> DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> > +		if (!obj)
> > +			return -AE_ERROR;
> > +		strncpy_attr(str_data[instance_id].current_value,
> > +			obj->package.elements[CURRENT_VAL].string.pointer);
> > +		kfree(obj);
> > +		return sprintf(buf, "%s\n", str_data[instance_id].current_value);
> > +	}
> > +	return -EIO;
> > +}
> > +
> > +/**
> > + * validate_str_input() - Validate input of current_value against min and
> max lengths
> > + * @instance_id: The instance on which input is validated
> > + * @buf: Input value
> > + **/
> > +int validate_str_input(int instance_id, const char *buf)
> > +{
> > +	int in_len = strlen(buf);
> > +
> > +	if ((in_len >= str_data[instance_id].min_length) &&
> > +	(in_len <= str_data[instance_id].max_length))
> > +		return 0;
> > +
> > +	return -EINVAL;
> > +}
> > +
> > +attribute_s_property_show(display_name_language_code, str);
> > +static struct kobj_attribute str_displ_langcode =
> > +		__ATTR_RO(display_name_language_code);
> > +
> > +attribute_s_property_show(display_name, str);
> > +struct kobj_attribute str_displ_name =
> > +		__ATTR_RO(display_name);
> > +
> > +attribute_s_property_show(default_value, str);
> > +struct kobj_attribute str_default_val =
> > +		__ATTR_RO(default_value);
> > +
> > +attribute_property_store(current_value, str);
> > +struct kobj_attribute str_current_val =
> > +		__ATTR_RW(current_value);
> > +
> > +attribute_s_property_show(modifier, str);
> > +struct kobj_attribute str_modifier =
> > +		__ATTR_RO(modifier);
> > +
> > +attribute_n_property_show(min_length, str);
> > +struct kobj_attribute str_min_length =
> > +		__ATTR_RO(min_length);
> > +
> > +attribute_n_property_show(max_length, str);
> > +struct kobj_attribute str_max_length =
> > +		__ATTR_RO(max_length);
> > +
> > +attribute_s_property_show(type, str);
> > +struct kobj_attribute str_type =
> > +	__ATTR_RO(type);
> > +
> > +static struct attribute *str_attrs[] = {
> > +	&str_displ_langcode.attr,
> > +	&str_displ_name.attr,
> > +	&str_default_val.attr,
> > +	&str_current_val.attr,
> > +	&str_modifier.attr,
> > +	&str_min_length.attr,
> > +	&str_max_length.attr,
> > +	&str_type.attr,
> > +	NULL,
> > +};
> > +
> > +static const struct attribute_group str_attr_group = {
> > +	.attrs = str_attrs,
> > +};
> > +
> > +int alloc_str_data(void)
> > +{
> > +	int ret = 0;
> > +
> > +	str_instances_count =
> get_instance_count(DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> > +	str_data = kzalloc((sizeof(struct str_data) * str_instances_count),
> GFP_KERNEL);
> > +	if (!str_data)
> > +		ret = -ENOMEM;
> > +	return ret;
> > +}
> > +
> > +/**
> > + * populate_enum_data() - Populate all properties of an instance under
> string attribute
> > + * @str_obj: ACPI object with integer data
> > + * @instance_id: The instance to enumerate
> > + * @attr_name_kobj: The parent kernel object
> > + **/
> > +int populate_str_data(union acpi_object *str_obj, int instance_id, struct
> kobject *attr_name_kobj)
> > +{
> > +	int retval = sysfs_create_group(attr_name_kobj, &str_attr_group);
> > +
> > +	if (retval)
> > +		goto out;
> > +
> > +	mutex_lock(&str_mutex);
> > +	strncpy_attr(str_data[instance_id].attribute_name,
> str_obj[ATTR_NAME].string.pointer);
> > +	strncpy_attr(str_data[instance_id].display_name_language_code,
> > +		str_obj[DISPL_NAME_LANG_CODE].string.pointer);
> > +	strncpy_attr(str_data[instance_id].display_name,
> str_obj[DISPLAY_NAME].string.pointer);
> > +	strncpy_attr(str_data[instance_id].default_value,
> str_obj[DEFAULT_VAL].string.pointer);
> > +	strncpy_attr(str_data[instance_id].current_value,
> str_obj[CURRENT_VAL].string.pointer);
> > +	strncpy_attr(str_data[instance_id].modifier,
> str_obj[MODIFIER].string.pointer);
> > +	str_data[instance_id].min_length =
> (uintptr_t)str_obj[MIN_LEN].string.pointer;
> > +	str_data[instance_id].max_length = (uintptr_t)
> str_obj[MAX_LEN].string.pointer;
> > +	strncpy_attr(str_data[instance_id].type, "string");
> > +	mutex_unlock(&str_mutex);
> > +
> > +out:
> > +	return retval;
> > +}
> > +
> > +/**
> > + * exit_str_attributes() - Clear all attribute data
> > + * @kset: The kset to free
> > + *
> > + * Clears all data allocated for this group of attributes
> > + **/
> > +void exit_str_attributes(struct kset *kset)
> > +{
> > +	struct kobject *pos, *next;
> > +
> > +	mutex_lock(&kset_mutex);
> > +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> > +		sysfs_remove_group(pos, &str_attr_group);
> > +	}
> > +	mutex_unlock(&kset_mutex);
> > +	mutex_lock(&str_mutex);
> > +	kfree(str_data);
> > +	mutex_unlock(&str_mutex);
> > +}
> > diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.c
> b/drivers/platform/x86/dell-wmi-sysman-attributes.c
> > new file mode 100644
> > index 000000000000..139d8f5d3d8e
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-sysman-attributes.c
> > @@ -0,0 +1,572 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Common methods for use with dell-wmi-sysman
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/dmi.h>
> > +#include <linux/wmi.h>
> > +#include "dell-wmi-sysman-attributes.h"
> > +
> > +DEFINE_MUTEX(kset_mutex);
> > +
> > +#define MAX_TYPES  4
> > +
> > +static struct platform_device *platform_device;
> > +
> > +static struct platform_driver platform_driver = {
> > +	.driver = {
> > +		.name = DRIVER_NAME,
> > +	},
> > +};
> > +
> > +/* global structure used by multiple WMI interfaces */
> > +struct dell_wmi_sysman_priv wmi_priv;
> > +
> > +/* attribute directory under platform dev */
> > +struct kset *main_dir_kset;
> > +
> > +/* reset bios to defaults */
> > +static const char * const reset_types[] = {"builtinsafe", "lastknowngood",
> "factory", "custom"};
> > +static int reset_option = -1;
> > +
> > +/**
> > + * calculate_security_buffer() - determines size of security buffer for
> authentication scheme
> > + *
> > + * Currently only supported type is Admin password
> > + **/
> > +size_t calculate_security_buffer(void)
> > +{
> > +	if (strlen(wmi_priv.current_admin_password) > 0) {
> > +		return (sizeof(u32) * 2) +
> > +			strlen(wmi_priv.current_admin_password) +
> > +			strlen(wmi_priv.current_admin_password) % 2;
> > +	}
> > +	return sizeof(u32) * 2;
> > +}
> > +
> > +/**
> > + * populate_security_buffer() - builds a security buffer for authentication
> scheme
> > + * @buffer: the buffer to populate
> > + * @authentication: the authentication content
> > + *
> > + * Currently only supported type is PLAIN TEXT
> > + **/
> > +void populate_security_buffer(char *buffer, char *authentication)
> > +{
> > +	char *auth = buffer + sizeof(u32)*2;
> > +	u32 *sectype = (u32 *) buffer;
> > +	u32 *seclen = sectype + 1;
> > +	/* plain text */
> > +	*sectype = 1;
> > +	*seclen = strlen(authentication);
> > +	strncpy(auth, authentication, *seclen);
> > +}
> > +
> > +/**
> > + * map_wmi_error() - map errors from WMI methods to kernel error codes
> > + **/
> > +int map_wmi_error(int error_code)
> > +{
> > +	switch (error_code) {
> > +	case 0:
> > +		/* success */
> > +		return 0;
> > +	case 1:
> > +		/* failed */
> > +		return -EIO;
> > +	case 2:
> > +		/* invalid parameter */
> > +		return -EINVAL;
> > +	case 3:
> > +		/* access denied */
> > +		return -EACCES;
> > +	case 4:
> > +		/* not supported */
> > +		return -EOPNOTSUPP;
> > +	case 5:
> > +		/* memory error */
> > +		return -ENOMEM;
> > +	case 6:
> > +		/* protocol error */
> > +		return -EPROTO;
> > +	}
> > +	/* unspecified error */
> > +	return -EIO;
> > +}
> > +
> > +/**
> > + * reset_bios_show() - sysfs implementaton for read reset_bios
> > + * @kobj: Kernel object for this attribute
> > + * @attr: Kernel object attribute
> > + * @buf: The buffer to display to userspace
> > + **/
> > +static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute
> *attr, char *buf)
> > +{
> > +	char *start = buf;
> > +	int i;
> > +
> > +	for (i = 0; i < MAX_TYPES; i++) {
> > +		if (i == reset_option)
> > +			buf += sprintf(buf, "[%s] ", reset_types[i]);
> > +		else
> > +			buf += sprintf(buf, "%s ", reset_types[i]);
> > +	}
> > +	buf += sprintf(buf, "\n");
> > +	return buf-start;
> > +}
> > +
> > +/**
> > + * reset_bios_store() - sysfs implementaton for write reset_bios
> > + * @kobj: Kernel object for this attribute
> > + * @attr: Kernel object attribute
> > + * @buf: The buffer from userspace
> > + * @count: the size of the buffer from userspace
> > + **/
> > +static ssize_t reset_bios_store(struct kobject *kobj,
> > +				struct kobj_attribute *attr, const char *buf, size_t
> count)
> > +{
> > +	int len, ret, i;
> > +	int type = -1;
> > +	char *p;
> > +
> > +	p = memchr(buf, '\n', count);
> > +	if (p != NULL)
> > +		*p = '\0';
> > +	len = p ? p - buf : count;
> > +
> > +	for (i = 0; i < MAX_TYPES; i++) {
> > +		if (len == strlen(reset_types[i])
> > +		    && !strncmp(buf, reset_types[i], len)) {
> > +			type = i;
> > +			break;
> > +		}
> > +	}
> > +
> > +	if (type < 0 || type >= MAX_TYPES) {
> > +		ret = -EINVAL;
> > +		goto out;
> > +	}
> > +
> > +	ret = set_bios_defaults(type);
> > +	dev_dbg(&platform_device->dev, "reset all attributes request type %d:
> %d", type, ret);
> > +	if (ret) {
> > +		ret = -EINVAL;
> > +	} else {
> > +		reset_option = type;
> > +		ret = count;
> > +	}
> > +
> > +out:
> > +	return ret;
> > +}
> > +
> > +/**
> > + * pending_reboot_show() - sysfs implementaton for read pending_reboot
> > + * @kobj: Kernel object for this attribute
> > + * @attr: Kernel object attribute
> > + * @buf: The buffer to display to userspace
> > + *
> > + * Stores default value as 0
> > + * When current_value is changed this attribute is set to 1 to notify
> reboot may be required
> > + **/
> > +static ssize_t pending_reboot_show(struct kobject *kobj, struct
> kobj_attribute *attr,
> > +				   char *buf)
> > +{
> > +	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
> > +}
> > +
> > +static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
> > +static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
> > +
> > +
> > +/**
> > + * create_reset_bios() - Creates reset_bios and pending_reboot attributes
> > + **/
> > +static int create_reset_bios(void)
> > +{
> > +	int ret = sysfs_create_file(&main_dir_kset->kobj, &reset_bios.attr);
> > +
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "could not create reset_bios file");
> > +		return ret;
> > +	}
> > +
> > +	ret = sysfs_create_file(&main_dir_kset->kobj, &pending_reboot.attr);
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "could not create
> changing_pending_reboot file");
> > +		sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
> > +	}
> > +	return ret;
> > +}
> > +
> > +static void release_reset_bios_data(void)
> > +{
> > +	sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
> > +	sysfs_remove_file(&main_dir_kset->kobj, &pending_reboot.attr);
> > +}
> > +
> > +static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
> > +			      char *buf)
> > +{
> > +	struct kobj_attribute *kattr;
> > +	ssize_t ret = -EIO;
> > +
> > +	kattr = container_of(attr, struct kobj_attribute, attr);
> > +	if (kattr->show)
> > +		ret = kattr->show(kobj, kattr, buf);
> > +	return ret;
> > +}
> > +
> > +static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute
> *attr,
> > +			       const char *buf, size_t count)
> > +{
> > +	struct kobj_attribute *kattr;
> > +	ssize_t ret = -EIO;
> > +
> > +	kattr = container_of(attr, struct kobj_attribute, attr);
> > +	if (kattr->store)
> > +		ret = kattr->store(kobj, kattr, buf, count);
> > +	return ret;
> > +}
> > +
> > +const struct sysfs_ops kobj_sysfs_ops = {
> > +	.show	= kobj_attr_show,
> > +	.store	= kobj_attr_store,
> > +};
> > +
> > +static void attr_name_release(struct kobject *kobj)
> > +{
> > +	kfree(kobj);
> > +}
> > +
> > +static struct kobj_type attr_name_ktype = {
> > +	.release	= attr_name_release,
> > +	.sysfs_ops	= &kobj_sysfs_ops,
> > +};
> > +
> > +/**
> > + * strncpy_attr - Copy a length-limited, NULL-terminated string with bound
> checks
> > + * @dest: Where to copy the string to
> > + * @src: Where to copy the string from
> > + **/
> > +void strncpy_attr(char *dest, char *src)
> > +{
> > +	size_t len = strlen(src) + 1;
> > +
> > +	if (len > 1 && len < MAX_BUFF)
> > +		strncpy(dest, src, len);
> > +}
> > +
> > +/**
> > + * get_wmiobj_pointer() - Get Content of WMI block for particular instance
> > + * @instance_id: WMI instance ID
> > + * @guid_string: WMI GUID (in str form)
> > + *
> > + * Fetches the content for WMI block (instance_id) under GUID (guid_string)
> > + * Caller must kfree the return
> > + **/
> > +union acpi_object *get_wmiobj_pointer(int instance_id, const char
> *guid_string)
> > +{
> > +	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
> > +	acpi_status status;
> > +
> > +	status = wmi_query_block(guid_string, instance_id, &out);
> > +
> > +	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
> > +}
> > +
> > +/**
> > + * get_instance_count() - Compute total number of instances under
> guid_string
> > + * @guid_string: WMI GUID (in string form)
> > + **/
> > +int get_instance_count(const char *guid_string)
> > +{
> > +	union acpi_object *wmi_obj = NULL;
> > +	int i = 0;
> > +
> > +	do {
> > +		kfree(wmi_obj);
> > +		wmi_obj = get_wmiobj_pointer(i, guid_string);
> > +		i++;
> > +	} while (wmi_obj);
> > +
> > +	return (i-1);
> > +}
> > +
> > +/**
> > + * alloc_attributes_data() - Allocate attributes data for a particular type
> > + * @attr_type: Attribute type to allocate
> > + **/
> > +static int alloc_attributes_data(int attr_type)
> > +{
> > +	int retval = 0;
> > +
> > +	switch (attr_type) {
> > +	case ENUM:
> > +		retval = alloc_enum_data();
> > +		break;
> > +	case INT:
> > +		retval = alloc_int_data();
> > +		break;
> > +	case STR:
> > +		retval = alloc_str_data();
> > +		break;
> > +	case PO:
> > +		retval = alloc_po_data();
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return retval;
> > +}
> > +
> > +/**
> > + * destroy_attribute_objs() - Free a kset of kobjects
> > + * @kset: The kset to destroy
> > + *
> > + * Fress kobjects created for each attribute_name under attribute type kset
> > + **/
> > +static void destroy_attribute_objs(struct kset *kset)
> > +{
> > +	struct kobject *pos, *next;
> > +
> > +	mutex_lock(&kset_mutex);
> > +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> > +		kobject_put(pos);
> > +	}
> > +	mutex_unlock(&kset_mutex);
> > +}
> > +
> > +/**
> > + * release_attributes_data() - Clean-up all sysfs directories and files
> created
> > + **/
> > +static void release_attributes_data(void)
> > +{
> > +	release_reset_bios_data();
> > +
> > +	exit_enum_attributes(main_dir_kset);
> > +	exit_int_attributes(main_dir_kset);
> > +	exit_str_attributes(main_dir_kset);
> > +	exit_po_attributes(main_dir_kset);
> > +
> > +	if (main_dir_kset) {
> > +		destroy_attribute_objs(main_dir_kset);
> > +		kset_unregister(main_dir_kset);
> > +	}
> 
> Why are the above 2 calls protected with a "if (main_dir_kset)" and the
> other 4 calls, which also take main_dir_kset as an argument not ?
> 
> Can we ever get here with main_dir_kset == NULL ?
> 
> > +}
> > +
> > +/**
> > + * init_bios_attributes() - Initialize all attributes for a type
> > + * @attr_type: The attribute type to initialize
> > + * @guid: The WMI GUID associated with this type to initialize
> > + *
> > + * Initialiaze all 4 types of attributes enumeration, integer, string and
> password object.
> > + * Populates each attrbute typ's respective properties under sysfs files
> > + **/
> > +static int init_bios_attributes(int attr_type, const char *guid)
> > +{
> > +	struct kobject *attr_name_kobj; //individual attribute names
> > +	union acpi_object *obj = NULL;
> > +	union acpi_object *elements;
> > +	int instance_id = 0;
> > +	int retval = 0;
> > +
> > +	retval = alloc_attributes_data(attr_type);
> > +	if (retval)
> > +		return retval;
> > +	obj = get_wmiobj_pointer(instance_id, guid);
> > +	if (!obj)
> > +		return -ENODEV;
> > +	elements = obj->package.elements;
> > +
> > +	while (elements) {
> > +		/* sanity checking */
> > +		if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
> > +			dev_dbg(&platform_device->dev, "empty attribute found");
> > +			goto nextobj;
> > +		}
> > +		if (kset_find_obj(main_dir_kset,
> elements[ATTR_NAME].string.pointer)) {
> > +			dev_dbg(&platform_device->dev, "duplicate attribute name found
> - %s",
> > +				elements[ATTR_NAME].string.pointer);
> > +			goto nextobj;
> > +		}
> > +
> > +		/* build attribute */
> > +		attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> > +		if (!attr_name_kobj)
> > +			goto err_attr_init;
> > +
> > +		attr_name_kobj->kset = main_dir_kset;
> > +
> > +		retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype,
> NULL, "%s",
> > +						elements[ATTR_NAME].string.pointer);
> > +		if (retval) {
> > +			kobject_put(attr_name_kobj);
> > +			goto err_attr_init;
> > +		}
> > +
> > +		/* enumerate all of this attribute */
> > +		switch (attr_type) {
> > +		case ENUM:
> > +			retval = populate_enum_data(elements, instance_id,
> attr_name_kobj);
> > +			break;
> > +		case INT:
> > +			retval = populate_int_data(elements, instance_id,
> attr_name_kobj);
> > +			break;
> > +		case STR:
> > +			retval = populate_str_data(elements, instance_id,
> attr_name_kobj);
> > +			break;
> > +		case PO:
> > +			retval = populate_po_data(elements, instance_id,
> attr_name_kobj);
> > +			break;
> > +		default:
> > +			break;
> > +		}
> > +
> > +		if (retval) {
> > +			dev_dbg(&platform_device->dev, "failed to populate %s",
> > +				elements[ATTR_NAME].string.pointer);
> > +			goto err_attr_init;
> > +		}
> > +
> > +nextobj:
> > +		kfree(obj);
> > +		instance_id++;
> > +		obj = get_wmiobj_pointer(instance_id, guid);
> > +		elements = obj ? obj->package.elements : NULL;
> > +	}
> > +
> > +	goto out;
> > +
> > +err_attr_init:
> > +	release_attributes_data();
> > +	kfree(obj);
> > +out:
> > +	return retval;
> > +}
> > +
> > +static int __init init_dell_bios_attrib_wmi(void)
> > +{
> > +	int ret = 0;
> > +
> > +	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
> > +	    !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
> > +		pr_err("Unable to run on non-Dell system\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	ret = init_dell_wmi_bios_attr_set_interface();
> > +	if (ret || !wmi_priv.bios_attr_wdev) {
> > +
> > +		dev_dbg(&platform_device->dev, "failed to initialize set
> interface");
> > +		goto fail_set_interface;
> > +	}
> > +
> > +	ret = init_dell_wmi_bios_attr_pass_interface();
> > +	if (ret || !wmi_priv.password_attr_wdev) {
> > +		dev_dbg(&platform_device->dev, "failed to initialize pass
> interface");
> > +		goto fail_pass_interface;
> > +	}
> > +
> > +	ret = platform_driver_register(&platform_driver);
> > +	if (ret)
> > +		goto fail_platform_driver;
> > +
> > +	platform_device = platform_device_alloc(DRIVER_NAME, -1);
> > +	if (!platform_device) {
> > +		ret = -ENOMEM;
> > +		goto fail_platform_device_alloc;
> > +	}
> > +
> > +	ret = platform_device_add(platform_device);
> > +	if (ret)
> > +		goto fail_platform_device_add;
> > +
> > +	main_dir_kset = kset_create_and_add("attributes", NULL,
> &platform_device->dev.kobj);
> > +	if (!main_dir_kset) {
> > +		ret = -ENOMEM;
> > +		goto fail_platform_device_add;
> > +	}
> > +
> > +	ret = create_reset_bios();
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "could not create reset BIOS
> attribute");
> > +		goto fail_kset;
> > +	}
> > +
> > +	ret = init_bios_attributes(ENUM,
> DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "failed to populate enumeration type
> attributes");
> > +		goto fail_create_group;
> > +	}
> > +
> > +	ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "failed to populate integer type
> attributes");
> > +		goto fail_create_group;
> > +	}
> > +
> > +	ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "failed to populate string type
> attributes");
> > +		goto fail_create_group;
> > +	}
> > +
> > +	ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
> > +	if (ret) {
> > +		dev_dbg(&platform_device->dev, "failed to populate pass object type
> attributes");
> > +		goto fail_create_group;
> > +	}
> > +
> > +	return 0;
> > +
> > +fail_create_group:
> > +	release_attributes_data();
> > +	platform_device_del(platform_device);
> > +
> > +fail_kset:
> > +	kset_unregister(main_dir_kset);
> > +
> > +fail_platform_device_add:
> > +	platform_device_put(platform_device);
> > +
> > +fail_platform_device_alloc:
> > +	platform_driver_unregister(&platform_driver);
> > +
> > +fail_platform_driver:
> > +	exit_dell_wmi_bios_attr_pass_interface();
> > +
> > +fail_pass_interface:
> > +	exit_dell_wmi_bios_attr_set_interface();
> > +
> > +fail_set_interface:
> > +	return ret;
> > +}
> > +
> > +static void __exit exit_dell_bios_attrib_wmi(void)
> > +{
> > +	release_attributes_data();
> > +	exit_dell_wmi_bios_attr_set_interface();
> > +	exit_dell_wmi_bios_attr_pass_interface();
> > +	if (platform_device) {
> > +		platform_device_unregister(platform_device);
> > +		platform_driver_unregister(&platform_driver);
> > +	}
> > +}
> > +
> > +module_init(init_dell_bios_attrib_wmi);
> > +module_exit(exit_dell_bios_attrib_wmi);
> > +
> > +MODULE_AUTHOR("Mario Limonciello <[e-mail]>");
> > +MODULE_AUTHOR("Prasanth Ksr <[e-mail]>");
> > +MODULE_AUTHOR("Divya Bharathi <[e-mail]>");
> > +MODULE_DESCRIPTION("Dell platform setting control interface");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.h
> b/drivers/platform/x86/dell-wmi-sysman-attributes.h
> > new file mode 100644
> > index 000000000000..a12c03ab96c9
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell-wmi-sysman-attributes.h
> > @@ -0,0 +1,132 @@
> > +/* SPDX-License-Identifier: GPL-2.0
> > + * Definitions for kernel modules using Dell WMI System Management Driver
> > + *
> > + *  Copyright (c) 2020 Dell Inc.
> > + */
> > +
> > +#ifndef _DELL_WMI_BIOS_ATTR_H_
> > +#define _DELL_WMI_BIOS_ATTR_H_
> > +
> > +#include <linux/wmi.h>
> > +#include <linux/device.h>
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/capability.h>
> > +
> > +#define DRIVER_NAME					"dell-wmi-sysman"
> > +#define MAX_BUFF  512
> > +
> > +#define DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID	"F1DDEE52-063C-4784-
> A11E-8A06684B9BF5"
> > +#define DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID		"F1DDEE52-063C-4784-
> A11E-8A06684B9BFA"
> > +#define DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID		"F1DDEE52-063C-4784-
> A11E-8A06684B9BF9"
> > +#define DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID		"0894B8D6-44A6-4719-
> 97D7-6AD24108BFD4"
> > +#define DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID		"F1DDEE52-063C-
> 4784-A11E-8A06684B9BF4"
> > +#define DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID		"70FE8229-D03B-
> 4214-A1C6-1F884B1A892A"
> > +
> > +struct dell_wmi_sysman_priv {
> > +	char current_admin_password[MAX_BUFF];
> > +	char current_system_password[MAX_BUFF];
> > +	struct wmi_device *password_attr_wdev;
> > +	struct wmi_device *bios_attr_wdev;
> > +	bool pending_changes;
> > +};
> > +
> > +enum { ENUM, INT, STR, PO };
> > +
> > +enum {
> > +	ATTR_NAME,
> > +	DISPL_NAME_LANG_CODE,
> > +	DISPLAY_NAME,
> > +	DEFAULT_VAL,
> > +	CURRENT_VAL,
> > +	MODIFIER
> > +};
> > +
> > +#define get_instance_id(type)							\
> > +int get_##type##_instance_id(struct kobject *kobj)				\
> > +{										\
> > +	int i;									\
> > +	for (i = 0; i <= type##_instances_count; i++) {				\
> > +		if (!(strcmp(kobj->name, type##_data[i].attribute_name)))	\
> > +			return i;						\
> > +	}									\
> > +	return -EIO;								\
> > +}
> > +
> > +#define attribute_s_property_show(name, type)					\
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute
> *attr,	\
> > +			   char *buf)						\
> > +{										\
> > +	int i = get_##type##_instance_id(kobj);					\
> > +	if (i >= 0)								\
> > +		return sprintf(buf, "%s\n", type##_data[i].name);		\
> > +	return 0;								\
> > +}
> > +
> > +#define attribute_n_property_show(name, type)					\
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute
> *attr,	\
> > +			   char *buf)						\
> > +{										\
> > +	int i = get_##type##_instance_id(kobj);					\
> > +	if (i >= 0)								\
> > +		return sprintf(buf, "%d\n", type##_data[i].name);		\
> > +	return 0;								\
> > +}
> > +
> > +#define attribute_property_store(curr_val, type)				\
> > +static ssize_t curr_val##_store(struct kobject *kobj,				\
> > +				struct kobj_attribute *attr,			\
> > +				const char *buf, size_t count)			\
> > +{										\
> > +	char *p = memchr(buf, '\n', count);					\
> > +	int ret = -EIO;								\
> > +	int i;									\
> > +										\
> > +	if (p != NULL)								\
> > +		*p = '\0';							\
> > +	i = get_##type##_instance_id(kobj);					\
> > +	if (i >= 0)								\
> > +		ret = validate_##type##_input(i, buf);				\
> > +	if (!ret)								\
> > +		ret = set_attribute(kobj->name, buf);				\
> > +	return ret ? ret : count;						\
> > +}
> > +
> > +union acpi_object *get_wmiobj_pointer(int instance_id, const char
> *guid_string);
> > +int get_instance_count(const char *guid_string);
> > +void strncpy_attr(char *dest, char *src);
> > +
> > +int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
> > +			struct kobject *attr_name_kobj);
> > +int alloc_enum_data(void);
> > +void exit_enum_attributes(struct kset *kset);
> > +
> > +int populate_int_data(union acpi_object *integer_obj, int instance_id,
> > +			struct kobject *attr_name_kobj);
> > +int alloc_int_data(void);
> > +void exit_int_attributes(struct kset *kset);
> > +
> > +int populate_str_data(union acpi_object *str_obj, int instance_id, struct
> kobject *attr_name_kobj);
> > +int alloc_str_data(void);
> > +void exit_str_attributes(struct kset *kset);
> > +
> > +int populate_po_data(union acpi_object *po_obj, int instance_id, struct
> kobject *attr_name_kobj);
> > +int alloc_po_data(void);
> > +void exit_po_attributes(struct kset *kset);
> > +
> > +int set_attribute(const char *a_name, const char *a_value);
> > +int set_bios_defaults(u8 defType);
> > +
> > +void exit_dell_wmi_bios_attr_set_interface(void);
> > +int init_dell_wmi_bios_attr_set_interface(void);
> > +int map_wmi_error(int error_code);
> > +size_t calculate_security_buffer(void);
> > +void populate_security_buffer(char *buffer, char *authentication);
> > +
> > +int set_current_password(const char *password_type, const char *cur);
> > +int set_new_password(const char *password_type, const char *new);
> > +int init_dell_wmi_bios_attr_pass_interface(void);
> > +void exit_dell_wmi_bios_attr_pass_interface(void);
> > +
> > +#endif
> >
> 
> Regards,
> 
> Hans

Bharathi, Divya Sept. 17, 2020, 5:22 a.m. UTC | #5

<snip>

> >
> > >
> > > > +
> > > > +/* kept variable names same as in sysfs file name for sysfs_show
> > > > +macro
> > > definition */
> > > > +struct enumeration_data {
> > > > +	char display_name_language_code[MAX_BUFF];
> > > > +	char attribute_name[MAX_BUFF];
> > > > +	char display_name[MAX_BUFF];
> > > > +	char default_value[MAX_BUFF];
> > > > +	char current_value[MAX_BUFF];
> > > > +	char modifier[MAX_BUFF];
> > > > +	int value_modifier_count;
> > > > +	char value_modifier[MAX_BUFF];
> > > > +	int possible_value_count;
> > > > +	char possible_value[MAX_BUFF];
> > > > +	char type[MAX_BUFF];
> > > > +};
> > > > +
> > > > +static struct enumeration_data *enumeration_data; static int
> > > > +enumeration_instances_count;
> > >
> > > Please store these 2 in the global wmi_priv data.
> > >
> > > Also there is a lot of overlap between structs like struct
> > > enumeration_data, struct integer_data, etc.
> > >
> > > I think it would be good to make a single struct attr_data, which
> > > contains fields for all the supported types.
> > >
> > > I also see a lot of overlapping code between:
> > >
> > > drivers/platform/x86/dell-wmi-enum-attributes.c
> > > drivers/platform/x86/dell-wmi-int-attributes.c
> > > drivers/platform/x86/dell-wmi-string-attributes.c
> > >
> > > I think that folding the data structures together will help with also
> > > unifying that code into a single dell-wmi-std-attributes.c file.
> > >
> 
> Yes, it does seem like lot of code is overlapping but they differ by
> properties that are little unnoticeable.
> 
> If we make single file adding switch cases we may end up in many
> switch cases and if conditions. Because, here only attribute_name,
> display_lang_code, display_lang and modifier are same. Apart from
> these other properties are different either by name or data type.
> 
> Also, one advantage here is if any new type is added in future it will
> be easier to create new sysfs_attr_group according to new type's
> properties
> 
> We will certainly try and minimize some identical looking code
> wherever possible and add inline comments/document the
> differences more clearly in v3 which is incoming shortly.
> 
> > > > +get_instance_id(enumeration);
> > > > +
> > > > +static ssize_t current_value_show(struct kobject *kobj, struct
> > > kobj_attribute *attr, char *buf)
> > > > +{
> > > > +	int instance_id;
> > > > +
> > > > +	if (!capable(CAP_SYS_ADMIN))
> > > > +		return -EPERM;
> > > > +	instance_id = get_enumeration_instance_id(kobj);
> > >
> > > If you unify the integer, string and enum code then this just becomes:
> > > get_std_instance_id(kobj)
> > >
> 
> For each type of attribute GUIDs are different and for each type
> instance IDs start from zero. So if we populate them in single data
> structure then instance IDs may overlap.
> 
> > > > +	if (instance_id >= 0) {
> > > > +		union acpi_object *obj;
> > > > +
> > > > +		obj = get_wmiobj_pointer(instance_id,
> > > DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> > > > +		if (!obj)
> > > > +			return -AE_ERROR;
> > >
> > > > +		strncpy_attr(enumeration_data[instance_id].current_value,
> > > > +		       obj->package.elements[CURRENT_VAL].string.pointer);
> > > So these 2 lines seem to be the only thing which is different for
> > > current_value_show, between enums, ints and strings, so you can put a
> > > simple switch-case on the type here.
> > >
> >
> > This is a good point, it will cause a lot of changes as a result and a lot less
> > code.
> >
> > > > +		kfree(obj);
> > > > +		return sprintf(buf, "%s\n",
> > > enumeration_data[instance_id].current_value);
> > > > +	}
> > > > +	return -EIO;
> > > > +} > +
> > > > +/**
> > > > + * validate_enumeration_input() - Validate input of current_value
> > > > +against
> > > possible values
> > > > + * @instance_id: The instance on which input is validated
> > > > + * @buf: Input value
> > > > + **/
> > > > +int validate_enumeration_input(int instance_id, const char *buf) {
> > > > +	char *options, *tmp, *p;
> > > > +	int ret = -EINVAL;
> > > > +
> > > > +	options = tmp =
> > > > +kstrdup((enumeration_data[instance_id].possible_value),
> > > GFP_KERNEL);
> > > > +	if (!options)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	while ((p = strsep(&options, ";")) != NULL) {
> > > > +		if (!*p)
> > > > +			continue;
> > > > +		if (!strncasecmp(p, buf, strlen(p))) {
> > > > +			ret = 0;
> > > > +			break;
> > > > +		}
> > > > +	}
> > > > +
> > > > +	kfree(tmp);
> > > > +	return ret;
> > > > +}
> > >
> > > For the validate functions you can keep all 3 in the new
> > > dell-wmi-std-attributes.c file and then call the right one through a
> > > switch-case based on the type.
> > >
> > > > +
> > > > +attribute_s_property_show(display_name_language_code,
> > enumeration);
> > > > +static struct kobj_attribute displ_langcode =
> > > > +		__ATTR_RO(display_name_language_code);
> > > > +
> > > > +attribute_s_property_show(display_name, enumeration); struct
> > > > +kobj_attribute displ_name =
> > > > +		__ATTR_RO(display_name);
> > > > +
> > > > +attribute_s_property_show(default_value, enumeration); struct
> > > > +kobj_attribute default_val =
> > > > +		__ATTR_RO(default_value);
> > > > +
> > > > +attribute_property_store(current_value, enumeration); struct
> > > > +kobj_attribute current_val =
> > > > +		__ATTR_RW(current_value);
> > > > +
> > > > +attribute_s_property_show(modifier, enumeration); struct
> > > > +kobj_attribute modifier =
> > > > +		__ATTR_RO(modifier);
> > > > +
> > > > +attribute_s_property_show(value_modifier, enumeration); struct
> > > > +kobj_attribute value_modfr =
> > > > +		__ATTR_RO(value_modifier);
> > > > +
> > > > +attribute_s_property_show(possible_value, enumeration); struct
> > > > +kobj_attribute poss_val =
> > > > +		__ATTR_RO(possible_value);
> > > > +
> > > > +attribute_s_property_show(type, enumeration); struct kobj_attribute
> > > > +type =
> > > > +		__ATTR_RO(type);
> > > > +
> > > > +static struct attribute *enumeration_attrs[] = {
> > > > +	&displ_langcode.attr,
> > > > +	&displ_name.attr,
> > > > +	&default_val.attr,
> > > > +	&current_val.attr,
> > > > +	&modifier.attr,
> > > > +	&value_modfr.attr,
> > > > +	&poss_val.attr,
> > > > +	&type.attr,
> > > > +	NULL,
> > > > +};
> > > > +
> > > > +static const struct attribute_group enumeration_attr_group = {
> > > > +	.attrs = enumeration_attrs,
> > > > +};
> > > > +
> > > > +int alloc_enum_data(void)
> > > > +{
> > > > +	int ret = 0;
> > > > +
> > > > +	enumeration_instances_count =
> > > get_instance_count(DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
> > > > +	enumeration_data = kzalloc((sizeof(struct enumeration_data) *
> > > enumeration_instances_count),
> > > > +					GFP_KERNEL);
> > > > +	if (!enumeration_data)
> > > > +		ret = -ENOMEM;
> > > > +	return ret;
> > > > +}
> > > > +
> > >
> > > The rest of the file is mostly identical between strings, ints and enums.
> > >
> > > > +/**
> > > > + * populate_enum_data() - Populate all properties of an instance
> > > > +under
> > > enumeration attribute
> > > > + * @enumeration_obj: ACPI object with enumeration data
> > > > + * @instance_id: The instance to enumerate
> > > > + * @attr_name_kobj: The parent kernel object  **/ int
> > > > +populate_enum_data(union acpi_object *enumeration_obj, int
> > instance_id,
> > > > +			struct kobject *attr_name_kobj)
> > > > +{
> > > > +	int retval = sysfs_create_group(attr_name_kobj,
> > > &enumeration_attr_group);
> > > > +	int i, next_obj;
> > > > +
> > > > +	if (retval)
> > > > +		goto out;
> > > > +
> > > > +	mutex_lock(&enum_mutex);
> > > > +	strncpy_attr(enumeration_data[instance_id].attribute_name,
> > > > +		enumeration_obj[ATTR_NAME].string.pointer);
> > > > +
> > 	strncpy_attr(enumeration_data[instance_id].display_name_language
> > _code,
> > > > +		enumeration_obj[DISPL_NAME_LANG_CODE].string.pointer);
> > > > +	strncpy_attr(enumeration_data[instance_id].display_name,
> > > > +		enumeration_obj[DISPLAY_NAME].string.pointer);
> > > > +	strncpy_attr(enumeration_data[instance_id].default_value,
> > > > +		enumeration_obj[DEFAULT_VAL].string.pointer);
> > > > +	strncpy_attr(enumeration_data[instance_id].current_value,
> > > > +		enumeration_obj[CURRENT_VAL].string.pointer);
> > > > +	strncpy_attr(enumeration_data[instance_id].modifier,
> > > > +		enumeration_obj[MODIFIER].string.pointer);
> > > > +
> > > > +	next_obj = MODIFIER + 1;
> > > > +
> > > > +	enumeration_data[instance_id].value_modifier_count =
> > > > +		(uintptr_t)enumeration_obj[next_obj].string.pointer;
> > > > +
> > > > +	for (i = 0; i <
> > > > +enumeration_data[instance_id].value_modifier_count; i++)
> > > {
> > > > +		strcat(enumeration_data[instance_id].value_modifier,
> > > > +			enumeration_obj[++next_obj].string.pointer);
> > > > +		strcat(enumeration_data[instance_id].value_modifier, ";");
> > > > +	}
> > > > +
> > > > +	enumeration_data[instance_id].possible_value_count =
> > > > +		(uintptr_t) enumeration_obj[++next_obj].string.pointer;
> > > > +
> > > > +	for (i = 0; i <
> > > > +enumeration_data[instance_id].possible_value_count; i++)
> > > {
> > > > +		strcat(enumeration_data[instance_id].possible_value,
> > > > +			enumeration_obj[++next_obj].string.pointer);
> > > > +		strcat(enumeration_data[instance_id].possible_value, ";");
> > > > +	}
> > > > +	strncpy_attr(enumeration_data[instance_id].type, "enumeration");
> > > > +	mutex_unlock(&enum_mutex);
> > > > +
> > > > +out:
> > > > +	return retval;
> > > > +}
> > >
> > >
> > > I guess you may also need a switch-case based on the type in the
> > > populare function.
> > >
> > > > +
> > > > +/**
> > > > + * exit_enum_attributes() - Clear all attribute data
> > > > + * @kset: The kset to free
> > > > + *
> > > > + * Clears all data allocated for this group of attributes  **/ void
> > > > +exit_enum_attributes(struct kset *kset) {
> > > > +	struct kobject *pos, *next;
> > > > +
> > > > +	mutex_lock(&kset_mutex);
> > > > +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
> > > > +		sysfs_remove_group(pos, &enumeration_attr_group);
> > > > +	}
> > > > +	mutex_unlock(&kset_mutex);
> > > > +	mutex_lock(&enum_mutex);
> > > > +	kfree(enumeration_data);
> > > > +	mutex_unlock(&enum_mutex);
> > > > +}
> > >
> > > Since there is now only 1 kset for the main dir, you are now calling
> > > sysfs_remove_group 4 times (for all the different times) on each entry
> > > in the attributes dir. I guess this may fail silently, but it still is
> > > not good. So this needs to be fixed.
> > >
> > > The remarks to this file also apply to the:
> > >
> > > drivers/platform/x86/dell-wmi-int-attributes.c
> > > drivers/platform/x86/dell-wmi-string-attributes.c
> > >
> > > files.
> > >

Since we maintained 4 different attribute groups under 1 kset, each time
respective attribute group will be removed. And once all groups are
removed, kset is deleted.

Regards,
Divya

Hans de Goede Sept. 21, 2020, 9:08 a.m. UTC | #6

Hi,

On 9/14/20 7:12 PM, Limonciello, Mario wrote:

<snip>

>>> +static int call_biosattributes_interface(struct wmi_device *wdev, char
>> *in_args, size_t size,
>>> +					int method_id)
>>> +{
>>> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
>>> +	struct acpi_buffer input;
>>> +	union acpi_object *obj;
>>> +	acpi_status status;
>>> +	int ret = -EIO;
>>> +
>>> +	input.length =  (acpi_size) size;
>>> +	input.pointer = in_args;
>>> +	status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
>>> +	if (ACPI_FAILURE(status))
>>> +		return -EIO;
>>> +	obj = (union acpi_object *)output.pointer;
>>> +	if (obj->type == ACPI_TYPE_INTEGER)
>>> +		ret = obj->integer.value;
>>> +
>>> +	kfree(output.pointer);
>>> +	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
>>
>> Why are you generating an uevent here? I think this needs a comment (or it
>> should be removed).
> 
> It's there so that userspace can know that a setting has been changed and doesn't
> need to poll the attribute indicating a reboot is pending.
> 
> We can certainly add a comment to this effect.

uevents are somewhat expensive they get processed by udevd, causing it
to evaluate all loaded udev rules and send out events to any userspace
processes listening for udev events.

The generic sysfs ABI allows polling using the poll() system-call
(so event driven) on sysfs attributes. IMHO it would be much better to
use this mechanism. Userspace can then poll() (watching for POLL_PRI)
on the pending_reboot sysfs attribute.

This could then be combined with a little helper for setting the
pending_changes bool, which checks if it is actually transitioning
from false to true and in that case does something like this:

kn = sysfs_get_dirent(..., "pending_reboot");
if (kn) {
	sysfs_notify_dirent(kn);
	sysfs_put(kn);
}

Note something like this really ought to be part of the sysfs ABI
documentation.


>>> +	return map_wmi_error(ret);
>>> +}
>>> +
>>> +/**
>>> + * set_attribute() - Update an attribute value
>>> + * @a_name: The attribute name
>>> + * @a_value: The attribute value
>>> + *
>>> + * Sets an attribute to new value
>>> + **/
>>> +int set_attribute(const char *a_name, const char *a_value)
>>> +{
>>> +	size_t security_area_size, string_area_size, buffer_size;
>>> +	char *attribute_name, *attribute_value;
>>> +	u8 *name_len, *value_len;
>>> +	char *buffer;
>>> +	int ret;
>>> +
>>> +	/* build/calculate buffer */
>>> +	security_area_size = calculate_security_buffer();
>>> +	string_area_size = (strlen(a_name) + strlen(a_value))*2;
>>> +	buffer_size = security_area_size + string_area_size + sizeof(u16) * 2;
>>> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
>>> +	if (!buffer)
>>> +		return -ENOMEM;
>>> +
>>> +	/* build security area */
>>> +	if (strlen(wmi_priv.current_admin_password) > 0)
>>> +		populate_security_buffer(buffer, wmi_priv.current_admin_password);
>>> +
>>> +	/* build variables to set */
>>> +	name_len = buffer + security_area_size;
>>> +	attribute_name = name_len + sizeof(u16);
>>> +	*name_len = utf8s_to_utf16s(a_name, strlen(a_name), UTF16_HOST_ENDIAN,
>>> +				    (wchar_t *) attribute_name, MAX_BUFF) * 2;
>>> +	if (*name_len < 0) {
>>> +		ret = -EINVAL;
>>> +		pr_err("UTF16 conversion failed");
>>> +		goto out_set_attribute;
>>> +	}
>>> +
>>> +	value_len = (u8 *) attribute_name + *name_len;
>>> +	attribute_value = value_len + sizeof(u16);
>>> +	*value_len = utf8s_to_utf16s(a_value, strlen(a_value),
>> UTF16_HOST_ENDIAN,
>>> +				    (wchar_t *) attribute_value, MAX_BUFF) * 2;
>>> +	if (*value_len < 0) {
>>> +		ret = -EINVAL;
>>> +		pr_err("UTF16 conversion failed");
>>> +		goto out_set_attribute;
>>> +	}
>>> +
>>> +	mutex_lock(&call_mutex);
>>> +	if (!wmi_priv.bios_attr_wdev) {
>>> +		ret = -ENODEV;
>>> +		pr_err("no WMI backend bound");
>>> +		goto out_set_attribute;
>>> +	}
>>
>> It is probably better to move this to the top, as I mentioned in my reply
>> to Mario, you could add something like this to the top of each function,
>> even before allocating the buffer and filling it.
> 
> The placement was intentional to avoid taking the mutex until data was validated.
> Is it preferable to make it specifically on entry into functions then?

See below.

>>
>>       mutex_lock(&wmi_priv.mutex);
>>
>>       if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
>>           ret = -ENODEV;
>>           goto out_set_attribute;
>>       }
>>
>> Note this requires that you initialize the buf pointer to NULL
>> when declaring it.
>>
>> Having this at the top of each function establishes a pattern where
>> it easy for a reader of the code to:
>>
>> a) See that the check is present when checking that the driver being
>> unbound is checked everywhere
>>
>> b) Ignore the check as "boilerplate" when looking at other parts of
>> the code
> 
> I guess this argument makes sense - setting up a pattern is a good way
> to spot the function that stands out when a coding mistake occurs.

Right.

Regards,

Hans

Hans de Goede Sept. 21, 2020, 9:18 a.m. UTC | #7

Hi,

On 9/15/20 6:28 PM, Bharathi, Divya wrote:

<snip>

>>>> +/* kept variable names same as in sysfs file name for sysfs_show
>>>> +macro
>>> definition */
>>>> +struct enumeration_data {
>>>> +	char display_name_language_code[MAX_BUFF];
>>>> +	char attribute_name[MAX_BUFF];
>>>> +	char display_name[MAX_BUFF];
>>>> +	char default_value[MAX_BUFF];
>>>> +	char current_value[MAX_BUFF];
>>>> +	char modifier[MAX_BUFF];
>>>> +	int value_modifier_count;
>>>> +	char value_modifier[MAX_BUFF];
>>>> +	int possible_value_count;
>>>> +	char possible_value[MAX_BUFF];
>>>> +	char type[MAX_BUFF];
>>>> +};
>>>> +
>>>> +static struct enumeration_data *enumeration_data; static int
>>>> +enumeration_instances_count;
>>>
>>> Please store these 2 in the global wmi_priv data.
>>>
>>> Also there is a lot of overlap between structs like struct
>>> enumeration_data, struct integer_data, etc.
>>>
>>> I think it would be good to make a single struct attr_data, which
>>> contains fields for all the supported types.
>>>
>>> I also see a lot of overlapping code between:
>>>
>>> drivers/platform/x86/dell-wmi-enum-attributes.c
>>> drivers/platform/x86/dell-wmi-int-attributes.c
>>> drivers/platform/x86/dell-wmi-string-attributes.c
>>>
>>> I think that folding the data structures together will help with also
>>> unifying that code into a single dell-wmi-std-attributes.c file.
>>>
> 
> Yes, it does seem like lot of code is overlapping but they differ by
> properties that are little unnoticeable.
> 
> If we make single file adding switch cases we may end up in many
> switch cases and if conditions. Because, here only attribute_name,
> display_lang_code, display_lang and modifier are same. Apart from
> these other properties are different either by name or data type.
> 
> Also, one advantage here is if any new type is added in future it will
> be easier to create new sysfs_attr_group according to new type's
> properties
> 
> We will certainly try and minimize some identical looking code
> wherever possible and add inline comments/document the
> differences more clearly in v3 which is incoming shortly.
> 
>>>> +get_instance_id(enumeration);
>>>> +
>>>> +static ssize_t current_value_show(struct kobject *kobj, struct
>>> kobj_attribute *attr, char *buf)
>>>> +{
>>>> +	int instance_id;
>>>> +
>>>> +	if (!capable(CAP_SYS_ADMIN))
>>>> +		return -EPERM;
>>>> +	instance_id = get_enumeration_instance_id(kobj);
>>>
>>> If you unify the integer, string and enum code then this just becomes:
>>> get_std_instance_id(kobj)
>>>
> 
> For each type of attribute GUIDs are different and for each type
> instance IDs start from zero. So if we populate them in single data
> structure then instance IDs may overlap.

Ah, I missed that, because of the switch-case in init_bios_attributes()
I assumed it was only called once and all attributes were enumerated
in a single loop.

I see that init_bios_attributes() gets called once for each of
ENUM, INT, STR and PO now. My mistake, sorry.

So you are right. Since the instance-ids overlap then my idea will not
work and we need to keep separate foo_data arrays per type.

It might still be worth it to unify enum_data, string_data and
integer_data into a single shared struct so that some of the
sysfs getter functions can be shared. I will leave that up to you.

Regards,

Hans

Hans de Goede Sept. 21, 2020, 9:38 a.m. UTC | #8

Hi,

On 9/17/20 7:22 AM, Bharathi, Divya wrote:

<snip>

>>>>> +
>>>>> +/**
>>>>> + * exit_enum_attributes() - Clear all attribute data
>>>>> + * @kset: The kset to free
>>>>> + *
>>>>> + * Clears all data allocated for this group of attributes  **/ void
>>>>> +exit_enum_attributes(struct kset *kset) {
>>>>> +	struct kobject *pos, *next;
>>>>> +
>>>>> +	mutex_lock(&kset_mutex);
>>>>> +	list_for_each_entry_safe(pos, next, &kset->list, entry) {
>>>>> +		sysfs_remove_group(pos, &enumeration_attr_group);
>>>>> +	}
>>>>> +	mutex_unlock(&kset_mutex);
>>>>> +	mutex_lock(&enum_mutex);
>>>>> +	kfree(enumeration_data);
>>>>> +	mutex_unlock(&enum_mutex);
>>>>> +}
>>>>
>>>> Since there is now only 1 kset for the main dir, you are now calling
>>>> sysfs_remove_group 4 times (for all the different times) on each entry
>>>> in the attributes dir. I guess this may fail silently, but it still is
>>>> not good. So this needs to be fixed.
>>>>
>>>> The remarks to this file also apply to the:
>>>>
>>>> drivers/platform/x86/dell-wmi-int-attributes.c
>>>> drivers/platform/x86/dell-wmi-string-attributes.c
>>>>
>>>> files.
>>>>
> 
> Since we maintained 4 different attribute groups under 1 kset, each time
> respective attribute group will be removed. And once all groups are
> removed, kset is deleted.

sysfs_remove_group() just does a kernfs_remove_by_name() for each
attribute in the group.

Since the integer_, enumeration_ and string_ attr_group-s all
have e.g. a current_value attribute that means that current_value
will be removed 3 times and for the 2nd and 3th call
kernfs_remove_by_name() will fail with -ENOENT.

Currently neither kernfs_remove_by_name() nor sysfs_remove_group() print
an error message for this, but still it is not very clean.

Instead why not do this:

int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
                         struct kobject *attr_name_kobj)
{
         int retval = sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
         int i, next_obj;

         if (retval)
                 goto out;

         mutex_lock(&wmi_priv.mutex);
	enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
	/* ^^^^^^^^^^^^^^^^ This line is new ^^^^^^^^^^^^^^^^^^^^^^^^*/
	...


void exit_enum_attributes(void)
{
         int i;

         for (i = 0; i < enumeration_instances_count; i++) {
		if (enumeration_data[instance_id].attr_name_kobj)
                         sysfs_remove_group(enumeration_data[instance_id].attr_name_kobj, &enumeration_attr_group);
	}

         kfree(enumeration_data);
}


That makes the teardown mirror the setup much more closely and as such is
a cleaner solution IMHO.

Regards,

Hans

Patch

diff --git a/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman b/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
new file mode 100644
index 000000000000..e4b608275ea4
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-dell-wmi-sysman
@@ -0,0 +1,126 @@ 
+What:		/sys/devices/platform/dell-wmi-sysman/attributes/
+Date:		December 2020
+KernelVersion:	5.10
+Contact:	Divya Bharathi <[e-mail]>,
+		Mario Limonciello <[e-mail]>,
+		Prasanth KSR <[e-mail]>
+Description:
+		The Dell WMI Systems Management Driver provides a sysfs interface
+		for systems management software to enable BIOS configuration
+		capability on certain Dell systems. This directory exposes
+		interfaces for interacting with BIOS attributes.
+
+		Attributes can accept a set of pre-defined valid values or a range of
+		numerical values or a string. An atribute can accept float as well,
+		if so '.' is used as decimal separator.
+
+		Also, BIOS Admin password and System Password can be set, reset or
+		cleared using these attributes. An "Admin" password is used for
+		preventing modification to the BIOS settings. A "System" password is
+		required to boot a machine.
+
+		current_value:	A file that can be read to obtain the current
+		value of the <attr>
+
+		This file can also be written to in order to update
+		the value of a <attr>
+
+		default_value:	A file that can be read to obtain the default
+		value of the <attr>
+
+		display_name:	A file that can be read to obtain a user friendly
+		description of the at <attr>
+
+		display_name_language_code:	A file that can be read to obtain
+		the IETF language tag corresponding to the "display_name" of the <attr>
+
+		modifier:	A file that can be read to obtain attribute-level
+		dependency rule. It says an attribute X will become read-only or
+		suppressed,	if attribute Y is not configured.
+		For example, AutoOnHr becomes read-only if AutoOn is disabled
+
+		possible_value:	A file that can be read to obtain the possible
+		values of the <attr>. Values are separated using semi-colon.
+
+		value_modifier:	A file that can be read to obtain value-level
+		dependency. This file is similar to modifier but here, an attribute's
+		current value will be forcefully changed based dependent attributes
+		value.
+		For example, current value of LegacyOrom will become Disabled if
+		SecureBoot is Enabled.
+
+		lower_bound:	A file that can be read to obtain the lower
+		bound value of the <attr>
+
+		upper_bound:	A file that can be read to obtain the upper
+		bound value of the <attr>
+
+		scalar_increment:	A file that can be read to obtain the
+		resolution of the incremental value this attribute accepts.
+
+		max_length:	A file that can be read to obtain the maximum
+		length value of the <attr>
+
+		min_length:	A file that can be read to obtain the minimum
+		length value of the <attr>
+
+		is_password_set:	A file that can be read
+		to obtain flag to see if a password is set on <attr>
+
+		max_password_length:	A file that can be read to obtain the
+		maximum length of the Password
+
+		min_password_length:	A file that can be read to obtain the
+		minimum length of the Password
+
+		current_password: A write only value used for privileged access
+		such as setting attributes when a system or admin password is set
+		or resetting to a new password
+
+		new_password: A write only value that when used in tandem with
+		current_password will reset a system or admin password.
+
+What:		/sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
+Date:		December 2020
+KernelVersion:	5.10
+Contact:	Divya Bharathi <[e-mail]>,
+		Mario Limonciello <[e-mail]>,
+		Prasanth KSR <[e-mail]>
+Description:
+		This attribute can be used to reset the BIOS Configuration.
+		Specifically, it tells which type of reset BIOS configuration is being
+		requested on the host.
+
+		Reading from it returns a list of supported options encoded as:
+
+			'builtinsafe' (Built in safe configuration profile)
+			'lastknowngood' (Last known good saved configuration profile)
+			'factory' (Default factory settings configuration profile)
+			'custom' (Custom saved configuration profile)
+
+		The currently selected option is printed in square brackets as
+		shown below:
+
+		# echo "factory" > sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
+
+		# cat sys/devices/platform/dell-wmi-sysman/attributes/reset_bios
+		# builtinsafe lastknowngood [factory] custom
+
+		Note that any changes to this attribute requires a reboot
+		for changes to take effect.
+
+What:		/sys/devices/platform/dell-wmi-sysman/attributes/pending_reboot
+Date:		December 2020
+KernelVersion:	5.10
+Contact:	Divya Bharathi <[e-mail]>,
+		Mario Limonciello <[e-mail]>,
+		Prasanth KSR <[e-mail]>
+Description:
+		A read-only attribute reads 1 if a reboot is necessary to apply
+		pending BIOS attribute changes.
+
+			0:	All BIOS attributes setting are current
+			1:	A reboot is necessary to get pending BIOS attribute changes
+				applied
+
+
diff --git a/MAINTAINERS b/MAINTAINERS
index 592467ba3f4d..36ca5671a62d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4940,6 +4940,15 @@  M:	Mario Limonciello <[e-mail]>
 S:	Maintained
 F:	drivers/platform/x86/dell-wmi-descriptor.c
 
+DELL WMI SYSMAN DRIVER
+M:	Divya Bharathi <[e-mail]>
+M:	Mario Limonciello <[e-mail]>
+M:	Prasanth Ksr <[e-mail]>
+L:	[e-mail]
+S:	Maintained
+F:	drivers/platform/x86/dell-wmi-*-attributes.*
+F:	drivers/platform/x86/dell-wmi-*-interface.c
+
 DELL WMI NOTIFICATIONS DRIVER
 M:	Matthew Garrett <[e-mail]>
 M:	Pali Rohár <[e-mail]>
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 40219bba6801..80646b328d72 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -430,6 +430,18 @@  config DELL_WMI
 	  To compile this driver as a module, choose M here: the module will
 	  be called dell-wmi.
 
+config DELL_WMI_SYSMAN
+	tristate "Dell WMI SYSMAN"
+	depends on ACPI_WMI
+	depends on DMI
+	select NLS
+	help
+	  This driver allows changing BIOS settings on many Dell machines from
+	  2018 and newer without the use of any additional software.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called dell-wmi-sysman.
+
 config DELL_WMI_DESCRIPTOR
 	tristate
 	depends on ACPI_WMI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 5f823f7eff45..dc2ccb574192 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -47,6 +47,14 @@  obj-$(CONFIG_DELL_WMI)			+= dell-wmi.o
 obj-$(CONFIG_DELL_WMI_DESCRIPTOR)	+= dell-wmi-descriptor.o
 obj-$(CONFIG_DELL_WMI_AIO)		+= dell-wmi-aio.o
 obj-$(CONFIG_DELL_WMI_LED)		+= dell-wmi-led.o
+obj-$(CONFIG_DELL_WMI_SYSMAN)  += dell-wmi-sysman.o
+dell-wmi-sysman-objs := dell-wmi-sysman-attributes.o \
+				 dell-wmi-enum-attributes.o \
+				 dell-wmi-int-attributes.o \
+				 dell-wmi-string-attributes.o \
+				 dell-wmi-passobj-attributes.o \
+				 dell-wmi-passwordattr-interface.o \
+				 dell-wmi-biosattr-interface.o
 
 # Fujitsu
 obj-$(CONFIG_AMILO_RFKILL)	+= amilo-rfkill.o
diff --git a/drivers/platform/x86/dell-wmi-biosattr-interface.c b/drivers/platform/x86/dell-wmi-biosattr-interface.c
new file mode 100644
index 000000000000..dda38d448fec
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-biosattr-interface.c
@@ -0,0 +1,198 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to SET methods under BIOS attributes interface GUID for use
+ * with dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include <linux/nls.h>
+#include <linux/wmi.h>
+#include "dell-wmi-sysman-attributes.h"
+
+#define SETDEFAULTVALUES_METHOD_ID					0x02
+#define SETBIOSDEFAULTS_METHOD_ID					0x03
+#define SETATTRIBUTE_METHOD_ID						0x04
+
+static DEFINE_MUTEX(call_mutex);
+
+extern struct dell_wmi_sysman_priv wmi_priv;
+
+static int call_biosattributes_interface(struct wmi_device *wdev, char *in_args, size_t size,
+					int method_id)
+{
+	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+	struct acpi_buffer input;
+	union acpi_object *obj;
+	acpi_status status;
+	int ret = -EIO;
+
+	input.length =  (acpi_size) size;
+	input.pointer = in_args;
+	status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+	obj = (union acpi_object *)output.pointer;
+	if (obj->type == ACPI_TYPE_INTEGER)
+		ret = obj->integer.value;
+
+	kfree(output.pointer);
+	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
+	return map_wmi_error(ret);
+}
+
+/**
+ * set_attribute() - Update an attribute value
+ * @a_name: The attribute name
+ * @a_value: The attribute value
+ *
+ * Sets an attribute to new value
+ **/
+int set_attribute(const char *a_name, const char *a_value)
+{
+	size_t security_area_size, string_area_size, buffer_size;
+	char *attribute_name, *attribute_value;
+	u8 *name_len, *value_len;
+	char *buffer;
+	int ret;
+
+	/* build/calculate buffer */
+	security_area_size = calculate_security_buffer();
+	string_area_size = (strlen(a_name) + strlen(a_value))*2;
+	buffer_size = security_area_size + string_area_size + sizeof(u16) * 2;
+	buffer = kzalloc(buffer_size, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	/* build security area */
+	if (strlen(wmi_priv.current_admin_password) > 0)
+		populate_security_buffer(buffer, wmi_priv.current_admin_password);
+
+	/* build variables to set */
+	name_len = buffer + security_area_size;
+	attribute_name = name_len + sizeof(u16);
+	*name_len = utf8s_to_utf16s(a_name, strlen(a_name), UTF16_HOST_ENDIAN,
+				    (wchar_t *) attribute_name, MAX_BUFF) * 2;
+	if (*name_len < 0) {
+		ret = -EINVAL;
+		pr_err("UTF16 conversion failed");
+		goto out_set_attribute;
+	}
+
+	value_len = (u8 *) attribute_name + *name_len;
+	attribute_value = value_len + sizeof(u16);
+	*value_len = utf8s_to_utf16s(a_value, strlen(a_value), UTF16_HOST_ENDIAN,
+				    (wchar_t *) attribute_value, MAX_BUFF) * 2;
+	if (*value_len < 0) {
+		ret = -EINVAL;
+		pr_err("UTF16 conversion failed");
+		goto out_set_attribute;
+	}
+
+	mutex_lock(&call_mutex);
+	if (!wmi_priv.bios_attr_wdev) {
+		ret = -ENODEV;
+		pr_err("no WMI backend bound");
+		goto out_set_attribute;
+	}
+
+	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
+					    buffer, buffer_size,
+					    SETATTRIBUTE_METHOD_ID);
+	if (ret == -EOPNOTSUPP)
+		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured");
+	else if (ret == -EACCES)
+		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
+
+	wmi_priv.pending_changes = 1;
+out_set_attribute:
+	kfree(buffer);
+	mutex_unlock(&call_mutex);
+
+	return ret;
+}
+
+/**
+ * set_bios_defaults() - Resets BIOS defaults
+ * @deftype: the type of BIOS value reset to issue.
+ *
+ * Resets BIOS defaults
+ **/
+int set_bios_defaults(u8 deftype)
+{
+	size_t security_area_size, buffer_size;
+	size_t integer_area_size = sizeof(u8);
+	u8 *defaultType;
+	char *buffer;
+	int ret;
+
+	security_area_size = calculate_security_buffer();
+	buffer_size = security_area_size + integer_area_size;
+	buffer = kzalloc(buffer_size, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	/* build security area */
+	if (strlen(wmi_priv.current_admin_password) > 0)
+		populate_security_buffer(buffer, wmi_priv.current_admin_password);
+
+	mutex_lock(&call_mutex);
+	if (!wmi_priv.bios_attr_wdev) {
+		ret = -ENODEV;
+		pr_err("no WMI backend bound");
+		goto out_bios_defaults;
+	}
+
+	defaultType = buffer + security_area_size;
+	*defaultType = deftype;
+
+	ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer, buffer_size,
+					    SETBIOSDEFAULTS_METHOD_ID);
+	if (ret)
+		dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed: %d", ret);
+	wmi_priv.pending_changes = 1;
+out_bios_defaults:
+	kfree(buffer);
+	mutex_unlock(&call_mutex);
+
+	return ret;
+}
+
+static int dell_wmi_bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
+{
+	wmi_priv.bios_attr_wdev = wdev;
+	return 0;
+}
+
+static int dell_wmi_bios_attr_set_interface_remove(struct wmi_device *wdev)
+{
+	mutex_lock(&call_mutex);
+	wmi_priv.bios_attr_wdev = NULL;
+	mutex_unlock(&call_mutex);
+	return 0;
+}
+
+static const struct wmi_device_id dell_wmi_bios_attr_set_interface_id_table[] = {
+	{ .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
+	{ },
+};
+static struct wmi_driver dell_wmi_bios_attr_set_interface_driver = {
+	.driver = {
+		.name = DRIVER_NAME"-set"
+	},
+	.probe = dell_wmi_bios_attr_set_interface_probe,
+	.remove = dell_wmi_bios_attr_set_interface_remove,
+	.id_table = dell_wmi_bios_attr_set_interface_id_table,
+};
+
+int init_dell_wmi_bios_attr_set_interface(void)
+{
+	return wmi_driver_register(&dell_wmi_bios_attr_set_interface_driver);
+}
+
+void exit_dell_wmi_bios_attr_set_interface(void)
+{
+	wmi_driver_unregister(&dell_wmi_bios_attr_set_interface_driver);
+}
+
+MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_set_interface_id_table);
diff --git a/drivers/platform/x86/dell-wmi-enum-attributes.c b/drivers/platform/x86/dell-wmi-enum-attributes.c
new file mode 100644
index 000000000000..f2370f067b6d
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-enum-attributes.c
@@ -0,0 +1,214 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to enumeration type attributes under BIOS Enumeration GUID for use
+ * with dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include "dell-wmi-sysman-attributes.h"
+
+static DEFINE_MUTEX(enum_mutex);
+extern struct mutex kset_mutex;
+
+/* kept variable names same as in sysfs file name for sysfs_show macro definition */
+struct enumeration_data {
+	char display_name_language_code[MAX_BUFF];
+	char attribute_name[MAX_BUFF];
+	char display_name[MAX_BUFF];
+	char default_value[MAX_BUFF];
+	char current_value[MAX_BUFF];
+	char modifier[MAX_BUFF];
+	int value_modifier_count;
+	char value_modifier[MAX_BUFF];
+	int possible_value_count;
+	char possible_value[MAX_BUFF];
+	char type[MAX_BUFF];
+};
+
+static struct enumeration_data *enumeration_data;
+static int enumeration_instances_count;
+get_instance_id(enumeration);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	instance_id = get_enumeration_instance_id(kobj);
+	if (instance_id >= 0) {
+		union acpi_object *obj;
+
+		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
+		if (!obj)
+			return -AE_ERROR;
+		strncpy_attr(enumeration_data[instance_id].current_value,
+		       obj->package.elements[CURRENT_VAL].string.pointer);
+		kfree(obj);
+		return sprintf(buf, "%s\n", enumeration_data[instance_id].current_value);
+	}
+	return -EIO;
+}
+
+/**
+ * validate_enumeration_input() - Validate input of current_value against possible values
+ * @instance_id: The instance on which input is validated
+ * @buf: Input value
+ **/
+int validate_enumeration_input(int instance_id, const char *buf)
+{
+	char *options, *tmp, *p;
+	int ret = -EINVAL;
+
+	options = tmp = kstrdup((enumeration_data[instance_id].possible_value), GFP_KERNEL);
+	if (!options)
+		return -ENOMEM;
+
+	while ((p = strsep(&options, ";")) != NULL) {
+		if (!*p)
+			continue;
+		if (!strncasecmp(p, buf, strlen(p))) {
+			ret = 0;
+			break;
+		}
+	}
+
+	kfree(tmp);
+	return ret;
+}
+
+attribute_s_property_show(display_name_language_code, enumeration);
+static struct kobj_attribute displ_langcode =
+		__ATTR_RO(display_name_language_code);
+
+attribute_s_property_show(display_name, enumeration);
+struct kobj_attribute displ_name =
+		__ATTR_RO(display_name);
+
+attribute_s_property_show(default_value, enumeration);
+struct kobj_attribute default_val =
+		__ATTR_RO(default_value);
+
+attribute_property_store(current_value, enumeration);
+struct kobj_attribute current_val =
+		__ATTR_RW(current_value);
+
+attribute_s_property_show(modifier, enumeration);
+struct kobj_attribute modifier =
+		__ATTR_RO(modifier);
+
+attribute_s_property_show(value_modifier, enumeration);
+struct kobj_attribute value_modfr =
+		__ATTR_RO(value_modifier);
+
+attribute_s_property_show(possible_value, enumeration);
+struct kobj_attribute poss_val =
+		__ATTR_RO(possible_value);
+
+attribute_s_property_show(type, enumeration);
+struct kobj_attribute type =
+		__ATTR_RO(type);
+
+static struct attribute *enumeration_attrs[] = {
+	&displ_langcode.attr,
+	&displ_name.attr,
+	&default_val.attr,
+	&current_val.attr,
+	&modifier.attr,
+	&value_modfr.attr,
+	&poss_val.attr,
+	&type.attr,
+	NULL,
+};
+
+static const struct attribute_group enumeration_attr_group = {
+	.attrs = enumeration_attrs,
+};
+
+int alloc_enum_data(void)
+{
+	int ret = 0;
+
+	enumeration_instances_count = get_instance_count(DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
+	enumeration_data = kzalloc((sizeof(struct enumeration_data) * enumeration_instances_count),
+					GFP_KERNEL);
+	if (!enumeration_data)
+		ret = -ENOMEM;
+	return ret;
+}
+
+/**
+ * populate_enum_data() - Populate all properties of an instance under enumeration attribute
+ * @enumeration_obj: ACPI object with enumeration data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ **/
+int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
+			struct kobject *attr_name_kobj)
+{
+	int retval = sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
+	int i, next_obj;
+
+	if (retval)
+		goto out;
+
+	mutex_lock(&enum_mutex);
+	strncpy_attr(enumeration_data[instance_id].attribute_name,
+		enumeration_obj[ATTR_NAME].string.pointer);
+	strncpy_attr(enumeration_data[instance_id].display_name_language_code,
+		enumeration_obj[DISPL_NAME_LANG_CODE].string.pointer);
+	strncpy_attr(enumeration_data[instance_id].display_name,
+		enumeration_obj[DISPLAY_NAME].string.pointer);
+	strncpy_attr(enumeration_data[instance_id].default_value,
+		enumeration_obj[DEFAULT_VAL].string.pointer);
+	strncpy_attr(enumeration_data[instance_id].current_value,
+		enumeration_obj[CURRENT_VAL].string.pointer);
+	strncpy_attr(enumeration_data[instance_id].modifier,
+		enumeration_obj[MODIFIER].string.pointer);
+
+	next_obj = MODIFIER + 1;
+
+	enumeration_data[instance_id].value_modifier_count =
+		(uintptr_t)enumeration_obj[next_obj].string.pointer;
+
+	for (i = 0; i < enumeration_data[instance_id].value_modifier_count; i++) {
+		strcat(enumeration_data[instance_id].value_modifier,
+			enumeration_obj[++next_obj].string.pointer);
+		strcat(enumeration_data[instance_id].value_modifier, ";");
+	}
+
+	enumeration_data[instance_id].possible_value_count =
+		(uintptr_t) enumeration_obj[++next_obj].string.pointer;
+
+	for (i = 0; i < enumeration_data[instance_id].possible_value_count; i++) {
+		strcat(enumeration_data[instance_id].possible_value,
+			enumeration_obj[++next_obj].string.pointer);
+		strcat(enumeration_data[instance_id].possible_value, ";");
+	}
+	strncpy_attr(enumeration_data[instance_id].type, "enumeration");
+	mutex_unlock(&enum_mutex);
+
+out:
+	return retval;
+}
+
+/**
+ * exit_enum_attributes() - Clear all attribute data
+ * @kset: The kset to free
+ *
+ * Clears all data allocated for this group of attributes
+ **/
+void exit_enum_attributes(struct kset *kset)
+{
+	struct kobject *pos, *next;
+
+	mutex_lock(&kset_mutex);
+	list_for_each_entry_safe(pos, next, &kset->list, entry) {
+		sysfs_remove_group(pos, &enumeration_attr_group);
+	}
+	mutex_unlock(&kset_mutex);
+	mutex_lock(&enum_mutex);
+	kfree(enumeration_data);
+	mutex_unlock(&enum_mutex);
+}
diff --git a/drivers/platform/x86/dell-wmi-int-attributes.c b/drivers/platform/x86/dell-wmi-int-attributes.c
new file mode 100644
index 000000000000..d922d4f73ce9
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-int-attributes.c
@@ -0,0 +1,195 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to integer type attributes under BIOS Integer GUID for use with
+ * dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include "dell-wmi-sysman-attributes.h"
+
+static DEFINE_MUTEX(int_mutex);
+extern struct mutex kset_mutex;
+
+enum int_properties {LOWER_BOUND = 6, UPPER_BOUND, SCALAR_INCR};
+
+/* kept variable names same as in sysfs file name for sysfs_show macro definition */
+struct integer_data {
+	char display_name_language_code[MAX_BUFF];
+	char attribute_name[MAX_BUFF];
+	char display_name[MAX_BUFF];
+	int default_value;
+	int current_value;
+	char modifier[MAX_BUFF];
+	int lower_bound;
+	int upper_bound;
+	int scalar_increment;
+	char type[MAX_BUFF];
+};
+
+static struct integer_data *integer_data;
+static int integer_instances_count;
+get_instance_id(integer);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	instance_id = get_integer_instance_id(kobj);
+	if (instance_id >= 0) {
+		union acpi_object *obj;
+
+		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
+		if (!obj)
+			return -AE_ERROR;
+		integer_data[instance_id].current_value =
+			(uintptr_t)obj->package.elements[CURRENT_VAL].string.pointer;
+		kfree(obj);
+		return sprintf(buf, "%d\n", integer_data[instance_id].current_value);
+	}
+	return -EIO;
+}
+
+/**
+ * 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
+ **/
+int validate_integer_input(int instance_id, const char *buf)
+{
+	int ret = -EINVAL;
+	int in_val;
+
+	if (kstrtoint(buf, 0, &in_val))
+		return ret;
+	if ((in_val >= integer_data[instance_id].lower_bound) &&
+	(in_val <= integer_data[instance_id].upper_bound))
+		ret = 0;
+
+	return ret;
+}
+
+attribute_s_property_show(display_name_language_code, integer);
+static struct kobj_attribute integer_displ_langcode =
+	__ATTR_RO(display_name_language_code);
+
+attribute_s_property_show(display_name, integer);
+struct kobj_attribute integer_displ_name =
+	__ATTR_RO(display_name);
+
+attribute_n_property_show(default_value, integer);
+struct kobj_attribute integer_default_val =
+	__ATTR_RO(default_value);
+
+attribute_property_store(current_value, integer);
+struct kobj_attribute integer_current_val =
+	__ATTR_RW(current_value);
+
+attribute_s_property_show(modifier, integer);
+struct kobj_attribute integer_modifier =
+	__ATTR_RO(modifier);
+
+attribute_n_property_show(lower_bound, integer);
+struct kobj_attribute integer_lower_bound =
+	__ATTR_RO(lower_bound);
+
+attribute_n_property_show(upper_bound, integer);
+struct kobj_attribute integer_upper_bound =
+	__ATTR_RO(upper_bound);
+
+attribute_n_property_show(scalar_increment, integer);
+struct kobj_attribute integer_scalar_increment =
+	__ATTR_RO(scalar_increment);
+
+attribute_s_property_show(type, integer);
+struct kobj_attribute integer_type =
+	__ATTR_RO(type);
+
+static struct attribute *integer_attrs[] = {
+	&integer_displ_langcode.attr,
+	&integer_displ_name.attr,
+	&integer_default_val.attr,
+	&integer_current_val.attr,
+	&integer_modifier.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 alloc_int_data(void)
+{
+	int ret = 0;
+
+	integer_instances_count = get_instance_count(DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
+	integer_data = kzalloc((sizeof(struct integer_data) * integer_instances_count), GFP_KERNEL);
+	if (!integer_data)
+		ret = -ENOMEM;
+	return ret;
+}
+
+/**
+ * populate_enum_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 populate_int_data(union acpi_object *integer_obj, int instance_id,
+			struct kobject *attr_name_kobj)
+{
+	int retval = sysfs_create_group(attr_name_kobj, &integer_attr_group);
+
+	if (retval)
+		goto out;
+
+	mutex_lock(&int_mutex);
+	strncpy_attr(integer_data[instance_id].attribute_name,
+		integer_obj[ATTR_NAME].string.pointer);
+	strncpy_attr(integer_data[instance_id].display_name_language_code,
+		integer_obj[DISPL_NAME_LANG_CODE].string.pointer);
+	strncpy_attr(integer_data[instance_id].display_name,
+		integer_obj[DISPLAY_NAME].string.pointer);
+	integer_data[instance_id].default_value =
+		(uintptr_t)integer_obj[DEFAULT_VAL].string.pointer;
+	integer_data[instance_id].current_value =
+		(uintptr_t)integer_obj[CURRENT_VAL].string.pointer;
+	strncpy_attr(integer_data[instance_id].modifier, integer_obj[MODIFIER].string.pointer);
+	integer_data[instance_id].lower_bound =
+		(uintptr_t)integer_obj[LOWER_BOUND].string.pointer;
+	integer_data[instance_id].upper_bound =
+		(uintptr_t)integer_obj[UPPER_BOUND].string.pointer;
+	integer_data[instance_id].scalar_increment =
+		(uintptr_t)integer_obj[SCALAR_INCR].string.pointer;
+	strncpy_attr(integer_data[instance_id].type, "integer");
+	mutex_unlock(&int_mutex);
+
+out:
+	return retval;
+}
+
+/**
+ * exit_int_attributes() - Clear all attribute data
+ * @kset: The kset to free
+ *
+ * Clears all data allocated for this group of attributes
+ **/
+void exit_int_attributes(struct kset *kset)
+{
+	struct kobject *pos, *next;
+
+	mutex_lock(&kset_mutex);
+	list_for_each_entry_safe(pos, next, &kset->list, entry) {
+		sysfs_remove_group(pos, &integer_attr_group);
+	}
+	mutex_unlock(&kset_mutex);
+	mutex_lock(&int_mutex);
+	kfree(integer_data);
+	mutex_unlock(&int_mutex);
+}
diff --git a/drivers/platform/x86/dell-wmi-passobj-attributes.c b/drivers/platform/x86/dell-wmi-passobj-attributes.c
new file mode 100644
index 000000000000..87bb7772bb18
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-passobj-attributes.c
@@ -0,0 +1,168 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to password object type attributes under BIOS Password Object GUID for
+ * use with dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include "dell-wmi-sysman-attributes.h"
+
+static DEFINE_MUTEX(po_mutex);
+extern struct mutex kset_mutex;
+
+enum po_properties {IS_PASS_SET = 1, MIN_PASS_LEN, MAX_PASS_LEN};
+
+/* kept variable names same as in sysfs file name for sysfs_show macro definition */
+struct po_data {
+	char attribute_name[MAX_BUFF];
+	int is_password_set;
+	int min_password_length;
+	int max_password_length;
+	char type[MAX_BUFF];
+};
+
+static struct po_data *po_data;
+static int po_instances_count;
+get_instance_id(po);
+
+static ssize_t is_password_set_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id = get_po_instance_id(kobj);
+
+	if (instance_id >= 0) {
+		union acpi_object *obj;
+
+		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
+		if (!obj)
+			return -AE_ERROR;
+		po_data[instance_id].is_password_set =
+			(uintptr_t)obj->package.elements[IS_PASS_SET].string.pointer;
+		kfree(obj);
+		return sprintf(buf, "%d\n", po_data[instance_id].is_password_set);
+	}
+	return -EIO;
+}
+
+struct kobj_attribute po_is_pass_set =
+		__ATTR_RO(is_password_set);
+
+static ssize_t current_password_store(struct kobject *kobj,
+				      struct kobj_attribute *attr,
+				      const char *buf, size_t count)
+{
+	char *p = memchr(buf, '\n', count);
+	int ret;
+
+	if (p != NULL)
+		*p = '\0';
+	if (strlen(buf) > MAX_BUFF)
+		return -EINVAL;
+
+	ret = set_current_password(kobj->name, buf);
+	return ret ? ret : count;
+}
+
+struct kobj_attribute po_current_password =
+		__ATTR_WO(current_password);
+
+static ssize_t new_password_store(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  const char *buf, size_t count)
+{
+	char *p = memchr(buf, '\n', count);
+	int ret;
+
+	if (p != NULL)
+		*p = '\0';
+	if (strlen(buf) > MAX_BUFF)
+		return -EINVAL;
+
+	ret = set_new_password(kobj->name, buf);
+	return ret ? ret : count;
+}
+
+struct kobj_attribute po_new_password =
+		__ATTR_WO(new_password);
+
+attribute_n_property_show(min_password_length, po);
+struct kobj_attribute po_min_pass_length =
+		__ATTR_RO(min_password_length);
+
+attribute_n_property_show(max_password_length, po);
+struct kobj_attribute po_max_pass_length =
+		__ATTR_RO(max_password_length);
+
+attribute_s_property_show(type, po);
+struct kobj_attribute po_type =
+	__ATTR_RO(type);
+
+static struct attribute *po_attrs[] = {
+	&po_is_pass_set.attr,
+	&po_min_pass_length.attr,
+	&po_max_pass_length.attr,
+	&po_current_password.attr,
+	&po_new_password.attr,
+	&po_type.attr,
+	NULL,
+};
+
+static const struct attribute_group po_attr_group = {
+	.attrs = po_attrs,
+};
+
+int alloc_po_data(void)
+{
+	int ret = 0;
+
+	po_instances_count = get_instance_count(DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
+	po_data = kzalloc((sizeof(struct po_data) * po_instances_count), GFP_KERNEL);
+	if (!po_data)
+		ret = -ENOMEM;
+	return ret;
+}
+
+/**
+ * populate_po_data() - Populate all properties of an instance under password object attribute
+ * @po_obj: ACPI object with password object data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ **/
+int populate_po_data(union acpi_object *po_obj, int instance_id, struct kobject *attr_name_kobj)
+{
+	int retval = sysfs_create_group(attr_name_kobj, &po_attr_group);
+
+	if (retval)
+		goto out;
+
+	mutex_lock(&po_mutex);
+	strncpy_attr(po_data[instance_id].attribute_name, po_obj[ATTR_NAME].string.pointer);
+	po_data[instance_id].is_password_set = (uintptr_t)po_obj[IS_PASS_SET].string.pointer;
+	po_data[instance_id].min_password_length = (uintptr_t)po_obj[MIN_PASS_LEN].string.pointer;
+	po_data[instance_id].max_password_length = (uintptr_t) po_obj[MAX_PASS_LEN].string.pointer;
+	strncpy_attr(po_data[instance_id].type, "password_object");
+	mutex_unlock(&po_mutex);
+
+out:
+	return retval;
+}
+
+/**
+ * exit_po_attributes() - Clear all attribute data
+ * @kset: The kset to free
+ *
+ * Clears all data allocated for this group of attributes
+ **/
+void exit_po_attributes(struct kset *kset)
+{
+	struct kobject *pos, *next;
+
+	mutex_lock(&kset_mutex);
+	list_for_each_entry_safe(pos, next, &kset->list, entry) {
+		sysfs_remove_group(pos, &po_attr_group);
+	}
+	mutex_unlock(&kset_mutex);
+	mutex_lock(&po_mutex);
+	kfree(po_data);
+	mutex_unlock(&po_mutex);
+}
diff --git a/drivers/platform/x86/dell-wmi-passwordattr-interface.c b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
new file mode 100644
index 000000000000..d105608cbb86
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-passwordattr-interface.c
@@ -0,0 +1,200 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to SET password methods under BIOS attributes interface GUID
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include <linux/nls.h>
+#include <linux/wmi.h>
+#include "dell-wmi-sysman-attributes.h"
+
+static DEFINE_MUTEX(call_mutex);
+extern struct dell_wmi_sysman_priv wmi_priv;
+
+static int call_password_interface(struct wmi_device *wdev, char *in_args, size_t size)
+{
+	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+	struct acpi_buffer input;
+	union acpi_object *obj;
+	acpi_status status;
+	int ret = -EIO;
+
+	input.length =  (acpi_size) size;
+	input.pointer = in_args;
+	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+	obj = (union acpi_object *)output.pointer;
+	if (obj->type == ACPI_TYPE_INTEGER)
+		ret = obj->integer.value;
+
+	kfree(output.pointer);
+	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
+	return map_wmi_error(ret);
+}
+
+/**
+ * get_current_password() - Get the current stored password value
+ * @password_type: The type of password to store
+ **/
+static char *get_current_password(const char *password_type)
+{
+	if (strcmp(password_type, "Admin") == 0)
+		return wmi_priv.current_admin_password;
+	if (strcmp(password_type, "System") == 0)
+		return wmi_priv.current_system_password;
+	dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s", password_type);
+	return NULL;
+}
+
+/**
+ * set_current_password() - Store current password
+ * @password_type: The type of password to store
+ * @current: The current value
+ *
+ * Sets the current value of the password.
+ * This is used for:
+ *  - Resetting password
+ *  - Basis for any functions requiring password to execute
+ **/
+int set_current_password(const char *password_type, const char *cur)
+{
+	char *current_password = get_current_password(password_type);
+
+	if (!current_password)
+		return -ENODEV;
+	strncpy(current_password, cur, (strlen(cur) + 1));
+	return 0;
+}
+
+/**
+ * set_new_password() - Sets a system admin password
+ * @password_type: The type of password to set
+ * @new: The new password
+ *
+ * Sets the password using plaintext interface
+ **/
+int set_new_password(const char *password_type, const char *new)
+{
+	char *current_password, *type_value, *old_value, *new_value;
+	size_t security_area_size, string_area_size, buffer_size;
+	u8 *type_len, *old_len, *new_len;
+	char *buffer;
+	int ret;
+
+	/* only allow one password set at a time */
+	mutex_lock(&call_mutex);
+	if (!wmi_priv.password_attr_wdev) {
+		ret = -ENODEV;
+		pr_err("no WMI backend bound");
+		goto out_close_mutex;
+	}
+	current_password = get_current_password(password_type);
+	if (!current_password) {
+		ret = -ENODEV;
+		goto out_close_mutex;
+	}
+
+	/* build/calculate buffer */
+	security_area_size = calculate_security_buffer();
+	string_area_size = (strlen(password_type) + strlen(current_password) + strlen(new))*2;
+	buffer_size = security_area_size + string_area_size + sizeof(u16) * 3;
+	buffer = kzalloc(buffer_size, GFP_KERNEL);
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto out_close_mutex;
+	}
+
+	/* build security area */
+	if (strlen(current_password) > 0)
+		populate_security_buffer(buffer, current_password);
+
+	/* build variables to set */
+	type_len = buffer + security_area_size;
+	type_value = type_len + sizeof(u16);
+	*type_len = utf8s_to_utf16s(password_type, strlen(password_type), UTF16_HOST_ENDIAN,
+				    (wchar_t *) type_value, MAX_BUFF) * 2;
+	if (*type_len < 0) {
+		ret = -EINVAL;
+		pr_err("UTF16 conversion failed");
+		goto out_cleanup;
+	}
+
+	old_len = type_value + *type_len;
+	old_value = old_len + sizeof(u16);
+	*old_len = utf8s_to_utf16s(current_password, strlen(current_password), UTF16_HOST_ENDIAN,
+				   (wchar_t *) old_value, MAX_BUFF) * 2;
+	if (*old_len < 0) {
+		ret = -EINVAL;
+		pr_err("UTF16 conversion failed");
+		goto out_cleanup;
+	}
+
+	new_len = old_value + *old_len;
+	new_value = new_len + sizeof(u16);
+	*new_len = utf8s_to_utf16s(new, strlen(new), UTF16_HOST_ENDIAN,
+				   (wchar_t *) new_value, MAX_BUFF) * 2;
+	if (*new_len < 0) {
+		ret = -EINVAL;
+		pr_err("UTF16 conversion failed");
+		goto out_cleanup;
+	}
+
+	ret = call_password_interface(wmi_priv.password_attr_wdev, buffer, buffer_size);
+	/* update current password so commands work after reset */
+	if (!ret)
+		ret = set_current_password(password_type, new);
+	/* explain to user the detailed failure reason */
+	else if (ret == -EOPNOTSUPP)
+		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured");
+	else if (ret == -EACCES)
+		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password");
+
+out_cleanup:
+	kfree(buffer);
+
+out_close_mutex:
+	mutex_unlock(&call_mutex);
+
+	return ret;
+}
+
+static int dell_wmi_bios_attr_pass_interface_probe(struct wmi_device *wdev, const void *context)
+{
+	wmi_priv.password_attr_wdev = wdev;
+	return 0;
+}
+
+static int dell_wmi_bios_attr_pass_interface_remove(struct wmi_device *wdev)
+{
+	mutex_lock(&call_mutex);
+	wmi_priv.password_attr_wdev = NULL;
+	mutex_unlock(&call_mutex);
+	return 0;
+}
+
+static const struct wmi_device_id dell_wmi_bios_attr_pass_interface_id_table[] = {
+	{ .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
+	{ },
+};
+static struct wmi_driver dell_wmi_bios_attr_pass_interface_driver = {
+	.driver = {
+		.name = DRIVER_NAME"-password"
+	},
+	.probe = dell_wmi_bios_attr_pass_interface_probe,
+	.remove = dell_wmi_bios_attr_pass_interface_remove,
+	.id_table = dell_wmi_bios_attr_pass_interface_id_table,
+};
+
+int init_dell_wmi_bios_attr_pass_interface(void)
+{
+	return wmi_driver_register(&dell_wmi_bios_attr_pass_interface_driver);
+}
+
+void exit_dell_wmi_bios_attr_pass_interface(void)
+{
+	wmi_driver_unregister(&dell_wmi_bios_attr_pass_interface_driver);
+}
+
+MODULE_DEVICE_TABLE(wmi, dell_wmi_bios_attr_pass_interface_id_table);
diff --git a/drivers/platform/x86/dell-wmi-string-attributes.c b/drivers/platform/x86/dell-wmi-string-attributes.c
new file mode 100644
index 000000000000..397de6fb13a3
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-string-attributes.c
@@ -0,0 +1,177 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to string type attributes under BIOS String GUID for use with
+ * dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include "dell-wmi-sysman-attributes.h"
+
+static DEFINE_MUTEX(str_mutex);
+extern struct mutex kset_mutex;
+
+enum string_properties {MIN_LEN = 6, MAX_LEN};
+
+/* kept variable names same as in sysfs file name for sysfs_show macro definition */
+struct str_data {
+	char display_name_language_code[MAX_BUFF];
+	char attribute_name[MAX_BUFF];
+	char display_name[MAX_BUFF];
+	char default_value[MAX_BUFF];
+	char current_value[MAX_BUFF];
+	char modifier[MAX_BUFF];
+	int min_length;
+	int max_length;
+	char type[MAX_BUFF];
+};
+
+static struct str_data *str_data;
+static int str_instances_count;
+get_instance_id(str);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	instance_id = get_str_instance_id(kobj);
+	if (instance_id >= 0) {
+		union acpi_object *obj;
+
+		obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
+		if (!obj)
+			return -AE_ERROR;
+		strncpy_attr(str_data[instance_id].current_value,
+			obj->package.elements[CURRENT_VAL].string.pointer);
+		kfree(obj);
+		return sprintf(buf, "%s\n", str_data[instance_id].current_value);
+	}
+	return -EIO;
+}
+
+/**
+ * validate_str_input() - Validate input of current_value against min and max lengths
+ * @instance_id: The instance on which input is validated
+ * @buf: Input value
+ **/
+int validate_str_input(int instance_id, const char *buf)
+{
+	int in_len = strlen(buf);
+
+	if ((in_len >= str_data[instance_id].min_length) &&
+	(in_len <= str_data[instance_id].max_length))
+		return 0;
+
+	return -EINVAL;
+}
+
+attribute_s_property_show(display_name_language_code, str);
+static struct kobj_attribute str_displ_langcode =
+		__ATTR_RO(display_name_language_code);
+
+attribute_s_property_show(display_name, str);
+struct kobj_attribute str_displ_name =
+		__ATTR_RO(display_name);
+
+attribute_s_property_show(default_value, str);
+struct kobj_attribute str_default_val =
+		__ATTR_RO(default_value);
+
+attribute_property_store(current_value, str);
+struct kobj_attribute str_current_val =
+		__ATTR_RW(current_value);
+
+attribute_s_property_show(modifier, str);
+struct kobj_attribute str_modifier =
+		__ATTR_RO(modifier);
+
+attribute_n_property_show(min_length, str);
+struct kobj_attribute str_min_length =
+		__ATTR_RO(min_length);
+
+attribute_n_property_show(max_length, str);
+struct kobj_attribute str_max_length =
+		__ATTR_RO(max_length);
+
+attribute_s_property_show(type, str);
+struct kobj_attribute str_type =
+	__ATTR_RO(type);
+
+static struct attribute *str_attrs[] = {
+	&str_displ_langcode.attr,
+	&str_displ_name.attr,
+	&str_default_val.attr,
+	&str_current_val.attr,
+	&str_modifier.attr,
+	&str_min_length.attr,
+	&str_max_length.attr,
+	&str_type.attr,
+	NULL,
+};
+
+static const struct attribute_group str_attr_group = {
+	.attrs = str_attrs,
+};
+
+int alloc_str_data(void)
+{
+	int ret = 0;
+
+	str_instances_count = get_instance_count(DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
+	str_data = kzalloc((sizeof(struct str_data) * str_instances_count), GFP_KERNEL);
+	if (!str_data)
+		ret = -ENOMEM;
+	return ret;
+}
+
+/**
+ * populate_enum_data() - Populate all properties of an instance under string attribute
+ * @str_obj: ACPI object with integer data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ **/
+int populate_str_data(union acpi_object *str_obj, int instance_id, struct kobject *attr_name_kobj)
+{
+	int retval = sysfs_create_group(attr_name_kobj, &str_attr_group);
+
+	if (retval)
+		goto out;
+
+	mutex_lock(&str_mutex);
+	strncpy_attr(str_data[instance_id].attribute_name, str_obj[ATTR_NAME].string.pointer);
+	strncpy_attr(str_data[instance_id].display_name_language_code,
+		str_obj[DISPL_NAME_LANG_CODE].string.pointer);
+	strncpy_attr(str_data[instance_id].display_name, str_obj[DISPLAY_NAME].string.pointer);
+	strncpy_attr(str_data[instance_id].default_value, str_obj[DEFAULT_VAL].string.pointer);
+	strncpy_attr(str_data[instance_id].current_value, str_obj[CURRENT_VAL].string.pointer);
+	strncpy_attr(str_data[instance_id].modifier, str_obj[MODIFIER].string.pointer);
+	str_data[instance_id].min_length = (uintptr_t)str_obj[MIN_LEN].string.pointer;
+	str_data[instance_id].max_length = (uintptr_t) str_obj[MAX_LEN].string.pointer;
+	strncpy_attr(str_data[instance_id].type, "string");
+	mutex_unlock(&str_mutex);
+
+out:
+	return retval;
+}
+
+/**
+ * exit_str_attributes() - Clear all attribute data
+ * @kset: The kset to free
+ *
+ * Clears all data allocated for this group of attributes
+ **/
+void exit_str_attributes(struct kset *kset)
+{
+	struct kobject *pos, *next;
+
+	mutex_lock(&kset_mutex);
+	list_for_each_entry_safe(pos, next, &kset->list, entry) {
+		sysfs_remove_group(pos, &str_attr_group);
+	}
+	mutex_unlock(&kset_mutex);
+	mutex_lock(&str_mutex);
+	kfree(str_data);
+	mutex_unlock(&str_mutex);
+}
diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.c b/drivers/platform/x86/dell-wmi-sysman-attributes.c
new file mode 100644
index 000000000000..139d8f5d3d8e
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-sysman-attributes.c
@@ -0,0 +1,572 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common methods for use with dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/dmi.h>
+#include <linux/wmi.h>
+#include "dell-wmi-sysman-attributes.h"
+
+DEFINE_MUTEX(kset_mutex);
+
+#define MAX_TYPES  4
+
+static struct platform_device *platform_device;
+
+static struct platform_driver platform_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+	},
+};
+
+/* global structure used by multiple WMI interfaces */
+struct dell_wmi_sysman_priv wmi_priv;
+
+/* attribute directory under platform dev */
+struct kset *main_dir_kset;
+
+/* reset bios to defaults */
+static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
+static int reset_option = -1;
+
+/**
+ * calculate_security_buffer() - determines size of security buffer for authentication scheme
+ *
+ * Currently only supported type is Admin password
+ **/
+size_t calculate_security_buffer(void)
+{
+	if (strlen(wmi_priv.current_admin_password) > 0) {
+		return (sizeof(u32) * 2) +
+			strlen(wmi_priv.current_admin_password) +
+			strlen(wmi_priv.current_admin_password) % 2;
+	}
+	return sizeof(u32) * 2;
+}
+
+/**
+ * populate_security_buffer() - builds a security buffer for authentication scheme
+ * @buffer: the buffer to populate
+ * @authentication: the authentication content
+ *
+ * Currently only supported type is PLAIN TEXT
+ **/
+void populate_security_buffer(char *buffer, char *authentication)
+{
+	char *auth = buffer + sizeof(u32)*2;
+	u32 *sectype = (u32 *) buffer;
+	u32 *seclen = sectype + 1;
+	/* plain text */
+	*sectype = 1;
+	*seclen = strlen(authentication);
+	strncpy(auth, authentication, *seclen);
+}
+
+/**
+ * map_wmi_error() - map errors from WMI methods to kernel error codes
+ **/
+int map_wmi_error(int error_code)
+{
+	switch (error_code) {
+	case 0:
+		/* success */
+		return 0;
+	case 1:
+		/* failed */
+		return -EIO;
+	case 2:
+		/* invalid parameter */
+		return -EINVAL;
+	case 3:
+		/* access denied */
+		return -EACCES;
+	case 4:
+		/* not supported */
+		return -EOPNOTSUPP;
+	case 5:
+		/* memory error */
+		return -ENOMEM;
+	case 6:
+		/* protocol error */
+		return -EPROTO;
+	}
+	/* unspecified error */
+	return -EIO;
+}
+
+/**
+ * reset_bios_show() - sysfs implementaton for read reset_bios
+ * @kobj: Kernel object for this attribute
+ * @attr: Kernel object attribute
+ * @buf: The buffer to display to userspace
+ **/
+static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	char *start = buf;
+	int i;
+
+	for (i = 0; i < MAX_TYPES; i++) {
+		if (i == reset_option)
+			buf += sprintf(buf, "[%s] ", reset_types[i]);
+		else
+			buf += sprintf(buf, "%s ", reset_types[i]);
+	}
+	buf += sprintf(buf, "\n");
+	return buf-start;
+}
+
+/**
+ * reset_bios_store() - sysfs implementaton for write reset_bios
+ * @kobj: Kernel object for this attribute
+ * @attr: Kernel object attribute
+ * @buf: The buffer from userspace
+ * @count: the size of the buffer from userspace
+ **/
+static ssize_t reset_bios_store(struct kobject *kobj,
+				struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	int len, ret, i;
+	int type = -1;
+	char *p;
+
+	p = memchr(buf, '\n', count);
+	if (p != NULL)
+		*p = '\0';
+	len = p ? p - buf : count;
+
+	for (i = 0; i < MAX_TYPES; i++) {
+		if (len == strlen(reset_types[i])
+		    && !strncmp(buf, reset_types[i], len)) {
+			type = i;
+			break;
+		}
+	}
+
+	if (type < 0 || type >= MAX_TYPES) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = set_bios_defaults(type);
+	dev_dbg(&platform_device->dev, "reset all attributes request type %d: %d", type, ret);
+	if (ret) {
+		ret = -EINVAL;
+	} else {
+		reset_option = type;
+		ret = count;
+	}
+
+out:
+	return ret;
+}
+
+/**
+ * pending_reboot_show() - sysfs implementaton for read pending_reboot
+ * @kobj: Kernel object for this attribute
+ * @attr: Kernel object attribute
+ * @buf: The buffer to display to userspace
+ *
+ * Stores default value as 0
+ * When current_value is changed this attribute is set to 1 to notify reboot may be required
+ **/
+static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
+				   char *buf)
+{
+	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
+}
+
+static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
+static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
+
+
+/**
+ * create_reset_bios() - Creates reset_bios and pending_reboot attributes
+ **/
+static int create_reset_bios(void)
+{
+	int ret = sysfs_create_file(&main_dir_kset->kobj, &reset_bios.attr);
+
+	if (ret) {
+		dev_dbg(&platform_device->dev, "could not create reset_bios file");
+		return ret;
+	}
+
+	ret = sysfs_create_file(&main_dir_kset->kobj, &pending_reboot.attr);
+	if (ret) {
+		dev_dbg(&platform_device->dev, "could not create changing_pending_reboot file");
+		sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
+	}
+	return ret;
+}
+
+static void release_reset_bios_data(void)
+{
+	sysfs_remove_file(&main_dir_kset->kobj, &reset_bios.attr);
+	sysfs_remove_file(&main_dir_kset->kobj, &pending_reboot.attr);
+}
+
+static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
+			      char *buf)
+{
+	struct kobj_attribute *kattr;
+	ssize_t ret = -EIO;
+
+	kattr = container_of(attr, struct kobj_attribute, attr);
+	if (kattr->show)
+		ret = kattr->show(kobj, kattr, buf);
+	return ret;
+}
+
+static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct kobj_attribute *kattr;
+	ssize_t ret = -EIO;
+
+	kattr = container_of(attr, struct kobj_attribute, attr);
+	if (kattr->store)
+		ret = kattr->store(kobj, kattr, buf, count);
+	return ret;
+}
+
+const struct sysfs_ops kobj_sysfs_ops = {
+	.show	= kobj_attr_show,
+	.store	= kobj_attr_store,
+};
+
+static void attr_name_release(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static struct kobj_type attr_name_ktype = {
+	.release	= attr_name_release,
+	.sysfs_ops	= &kobj_sysfs_ops,
+};
+
+/**
+ * strncpy_attr - Copy a length-limited, NULL-terminated string with bound checks
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ **/
+void strncpy_attr(char *dest, char *src)
+{
+	size_t len = strlen(src) + 1;
+
+	if (len > 1 && len < MAX_BUFF)
+		strncpy(dest, src, len);
+}
+
+/**
+ * get_wmiobj_pointer() - Get Content of WMI block for particular instance
+ * @instance_id: WMI instance ID
+ * @guid_string: WMI GUID (in str form)
+ *
+ * Fetches the content for WMI block (instance_id) under GUID (guid_string)
+ * Caller must kfree the return
+ **/
+union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
+{
+	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
+	acpi_status status;
+
+	status = wmi_query_block(guid_string, instance_id, &out);
+
+	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
+}
+
+/**
+ * get_instance_count() - Compute total number of instances under guid_string
+ * @guid_string: WMI GUID (in string form)
+ **/
+int get_instance_count(const char *guid_string)
+{
+	union acpi_object *wmi_obj = NULL;
+	int i = 0;
+
+	do {
+		kfree(wmi_obj);
+		wmi_obj = get_wmiobj_pointer(i, guid_string);
+		i++;
+	} while (wmi_obj);
+
+	return (i-1);
+}
+
+/**
+ * alloc_attributes_data() - Allocate attributes data for a particular type
+ * @attr_type: Attribute type to allocate
+ **/
+static int alloc_attributes_data(int attr_type)
+{
+	int retval = 0;
+
+	switch (attr_type) {
+	case ENUM:
+		retval = alloc_enum_data();
+		break;
+	case INT:
+		retval = alloc_int_data();
+		break;
+	case STR:
+		retval = alloc_str_data();
+		break;
+	case PO:
+		retval = alloc_po_data();
+		break;
+	default:
+		break;
+	}
+
+	return retval;
+}
+
+/**
+ * destroy_attribute_objs() - Free a kset of kobjects
+ * @kset: The kset to destroy
+ *
+ * Fress kobjects created for each attribute_name under attribute type kset
+ **/
+static void destroy_attribute_objs(struct kset *kset)
+{
+	struct kobject *pos, *next;
+
+	mutex_lock(&kset_mutex);
+	list_for_each_entry_safe(pos, next, &kset->list, entry) {
+		kobject_put(pos);
+	}
+	mutex_unlock(&kset_mutex);
+}
+
+/**
+ * release_attributes_data() - Clean-up all sysfs directories and files created
+ **/
+static void release_attributes_data(void)
+{
+	release_reset_bios_data();
+
+	exit_enum_attributes(main_dir_kset);
+	exit_int_attributes(main_dir_kset);
+	exit_str_attributes(main_dir_kset);
+	exit_po_attributes(main_dir_kset);
+
+	if (main_dir_kset) {
+		destroy_attribute_objs(main_dir_kset);
+		kset_unregister(main_dir_kset);
+	}
+}
+
+/**
+ * init_bios_attributes() - Initialize all attributes for a type
+ * @attr_type: The attribute type to initialize
+ * @guid: The WMI GUID associated with this type to initialize
+ *
+ * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
+ * Populates each attrbute typ's respective properties under sysfs files
+ **/
+static int init_bios_attributes(int attr_type, const char *guid)
+{
+	struct kobject *attr_name_kobj; //individual attribute names
+	union acpi_object *obj = NULL;
+	union acpi_object *elements;
+	int instance_id = 0;
+	int retval = 0;
+
+	retval = alloc_attributes_data(attr_type);
+	if (retval)
+		return retval;
+	obj = get_wmiobj_pointer(instance_id, guid);
+	if (!obj)
+		return -ENODEV;
+	elements = obj->package.elements;
+
+	while (elements) {
+		/* sanity checking */
+		if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
+			dev_dbg(&platform_device->dev, "empty attribute found");
+			goto nextobj;
+		}
+		if (kset_find_obj(main_dir_kset, elements[ATTR_NAME].string.pointer)) {
+			dev_dbg(&platform_device->dev, "duplicate attribute name found - %s",
+				elements[ATTR_NAME].string.pointer);
+			goto nextobj;
+		}
+
+		/* build attribute */
+		attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
+		if (!attr_name_kobj)
+			goto err_attr_init;
+
+		attr_name_kobj->kset = main_dir_kset;
+
+		retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
+						elements[ATTR_NAME].string.pointer);
+		if (retval) {
+			kobject_put(attr_name_kobj);
+			goto err_attr_init;
+		}
+
+		/* enumerate all of this attribute */
+		switch (attr_type) {
+		case ENUM:
+			retval = populate_enum_data(elements, instance_id, attr_name_kobj);
+			break;
+		case INT:
+			retval = populate_int_data(elements, instance_id, attr_name_kobj);
+			break;
+		case STR:
+			retval = populate_str_data(elements, instance_id, attr_name_kobj);
+			break;
+		case PO:
+			retval = populate_po_data(elements, instance_id, attr_name_kobj);
+			break;
+		default:
+			break;
+		}
+
+		if (retval) {
+			dev_dbg(&platform_device->dev, "failed to populate %s",
+				elements[ATTR_NAME].string.pointer);
+			goto err_attr_init;
+		}
+
+nextobj:
+		kfree(obj);
+		instance_id++;
+		obj = get_wmiobj_pointer(instance_id, guid);
+		elements = obj ? obj->package.elements : NULL;
+	}
+
+	goto out;
+
+err_attr_init:
+	release_attributes_data();
+	kfree(obj);
+out:
+	return retval;
+}
+
+static int __init init_dell_bios_attrib_wmi(void)
+{
+	int ret = 0;
+
+	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
+	    !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
+		pr_err("Unable to run on non-Dell system\n");
+		return -ENODEV;
+	}
+
+	ret = init_dell_wmi_bios_attr_set_interface();
+	if (ret || !wmi_priv.bios_attr_wdev) {
+
+		dev_dbg(&platform_device->dev, "failed to initialize set interface");
+		goto fail_set_interface;
+	}
+
+	ret = init_dell_wmi_bios_attr_pass_interface();
+	if (ret || !wmi_priv.password_attr_wdev) {
+		dev_dbg(&platform_device->dev, "failed to initialize pass interface");
+		goto fail_pass_interface;
+	}
+
+	ret = platform_driver_register(&platform_driver);
+	if (ret)
+		goto fail_platform_driver;
+
+	platform_device = platform_device_alloc(DRIVER_NAME, -1);
+	if (!platform_device) {
+		ret = -ENOMEM;
+		goto fail_platform_device_alloc;
+	}
+
+	ret = platform_device_add(platform_device);
+	if (ret)
+		goto fail_platform_device_add;
+
+	main_dir_kset = kset_create_and_add("attributes", NULL, &platform_device->dev.kobj);
+	if (!main_dir_kset) {
+		ret = -ENOMEM;
+		goto fail_platform_device_add;
+	}
+
+	ret = create_reset_bios();
+	if (ret) {
+		dev_dbg(&platform_device->dev, "could not create reset BIOS attribute");
+		goto fail_kset;
+	}
+
+	ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
+	if (ret) {
+		dev_dbg(&platform_device->dev, "failed to populate enumeration type attributes");
+		goto fail_create_group;
+	}
+
+	ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
+	if (ret) {
+		dev_dbg(&platform_device->dev, "failed to populate integer type attributes");
+		goto fail_create_group;
+	}
+
+	ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
+	if (ret) {
+		dev_dbg(&platform_device->dev, "failed to populate string type attributes");
+		goto fail_create_group;
+	}
+
+	ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
+	if (ret) {
+		dev_dbg(&platform_device->dev, "failed to populate pass object type attributes");
+		goto fail_create_group;
+	}
+
+	return 0;
+
+fail_create_group:
+	release_attributes_data();
+	platform_device_del(platform_device);
+
+fail_kset:
+	kset_unregister(main_dir_kset);
+
+fail_platform_device_add:
+	platform_device_put(platform_device);
+
+fail_platform_device_alloc:
+	platform_driver_unregister(&platform_driver);
+
+fail_platform_driver:
+	exit_dell_wmi_bios_attr_pass_interface();
+
+fail_pass_interface:
+	exit_dell_wmi_bios_attr_set_interface();
+
+fail_set_interface:
+	return ret;
+}
+
+static void __exit exit_dell_bios_attrib_wmi(void)
+{
+	release_attributes_data();
+	exit_dell_wmi_bios_attr_set_interface();
+	exit_dell_wmi_bios_attr_pass_interface();
+	if (platform_device) {
+		platform_device_unregister(platform_device);
+		platform_driver_unregister(&platform_driver);
+	}
+}
+
+module_init(init_dell_bios_attrib_wmi);
+module_exit(exit_dell_bios_attrib_wmi);
+
+MODULE_AUTHOR("Mario Limonciello <[e-mail]>");
+MODULE_AUTHOR("Prasanth Ksr <[e-mail]>");
+MODULE_AUTHOR("Divya Bharathi <[e-mail]>");
+MODULE_DESCRIPTION("Dell platform setting control interface");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/dell-wmi-sysman-attributes.h b/drivers/platform/x86/dell-wmi-sysman-attributes.h
new file mode 100644
index 000000000000..a12c03ab96c9
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-sysman-attributes.h
@@ -0,0 +1,132 @@ 
+/* SPDX-License-Identifier: GPL-2.0
+ * Definitions for kernel modules using Dell WMI System Management Driver
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#ifndef _DELL_WMI_BIOS_ATTR_H_
+#define _DELL_WMI_BIOS_ATTR_H_
+
+#include <linux/wmi.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/capability.h>
+
+#define DRIVER_NAME					"dell-wmi-sysman"
+#define MAX_BUFF  512
+
+#define DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID	"F1DDEE52-063C-4784-A11E-8A06684B9BF5"
+#define DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID		"F1DDEE52-063C-4784-A11E-8A06684B9BFA"
+#define DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID		"F1DDEE52-063C-4784-A11E-8A06684B9BF9"
+#define DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID		"0894B8D6-44A6-4719-97D7-6AD24108BFD4"
+#define DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID		"F1DDEE52-063C-4784-A11E-8A06684B9BF4"
+#define DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID		"70FE8229-D03B-4214-A1C6-1F884B1A892A"
+
+struct dell_wmi_sysman_priv {
+	char current_admin_password[MAX_BUFF];
+	char current_system_password[MAX_BUFF];
+	struct wmi_device *password_attr_wdev;
+	struct wmi_device *bios_attr_wdev;
+	bool pending_changes;
+};
+
+enum { ENUM, INT, STR, PO };
+
+enum {
+	ATTR_NAME,
+	DISPL_NAME_LANG_CODE,
+	DISPLAY_NAME,
+	DEFAULT_VAL,
+	CURRENT_VAL,
+	MODIFIER
+};
+
+#define get_instance_id(type)							\
+int get_##type##_instance_id(struct kobject *kobj)				\
+{										\
+	int i;									\
+	for (i = 0; i <= type##_instances_count; i++) {				\
+		if (!(strcmp(kobj->name, type##_data[i].attribute_name)))	\
+			return i;						\
+	}									\
+	return -EIO;								\
+}
+
+#define attribute_s_property_show(name, type)					\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
+			   char *buf)						\
+{										\
+	int i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		return sprintf(buf, "%s\n", type##_data[i].name);		\
+	return 0;								\
+}
+
+#define attribute_n_property_show(name, type)					\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
+			   char *buf)						\
+{										\
+	int i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		return sprintf(buf, "%d\n", type##_data[i].name);		\
+	return 0;								\
+}
+
+#define attribute_property_store(curr_val, type)				\
+static ssize_t curr_val##_store(struct kobject *kobj,				\
+				struct kobj_attribute *attr,			\
+				const char *buf, size_t count)			\
+{										\
+	char *p = memchr(buf, '\n', count);					\
+	int ret = -EIO;								\
+	int i;									\
+										\
+	if (p != NULL)								\
+		*p = '\0';							\
+	i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		ret = validate_##type##_input(i, buf);				\
+	if (!ret)								\
+		ret = set_attribute(kobj->name, buf);				\
+	return ret ? ret : count;						\
+}
+
+union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string);
+int get_instance_count(const char *guid_string);
+void strncpy_attr(char *dest, char *src);
+
+int populate_enum_data(union acpi_object *enumeration_obj, int instance_id,
+			struct kobject *attr_name_kobj);
+int alloc_enum_data(void);
+void exit_enum_attributes(struct kset *kset);
+
+int populate_int_data(union acpi_object *integer_obj, int instance_id,
+			struct kobject *attr_name_kobj);
+int alloc_int_data(void);
+void exit_int_attributes(struct kset *kset);
+
+int populate_str_data(union acpi_object *str_obj, int instance_id, struct kobject *attr_name_kobj);
+int alloc_str_data(void);
+void exit_str_attributes(struct kset *kset);
+
+int populate_po_data(union acpi_object *po_obj, int instance_id, struct kobject *attr_name_kobj);
+int alloc_po_data(void);
+void exit_po_attributes(struct kset *kset);
+
+int set_attribute(const char *a_name, const char *a_value);
+int set_bios_defaults(u8 defType);
+
+void exit_dell_wmi_bios_attr_set_interface(void);
+int init_dell_wmi_bios_attr_set_interface(void);
+int map_wmi_error(int error_code);
+size_t calculate_security_buffer(void);
+void populate_security_buffer(char *buffer, char *authentication);
+
+int set_current_password(const char *password_type, const char *cur);
+int set_new_password(const char *password_type, const char *new);
+int init_dell_wmi_bios_attr_pass_interface(void);
+void exit_dell_wmi_bios_attr_pass_interface(void);
+
+#endif