Re: [PATCH v4 2/6] Introduction of HP-BIOSCFG driver

[Hans de Goede <hdegoede@redhat.com>]

Hi Jorge,

Review comments inline.

On 10/20/22 22:10, Jorge Lopez wrote:
> The purpose for this patch is submit HP BIOSCFG driver to be list of
> HP Linux kernel drivers.  The driver include a total of 12 files
> broken in several patches.  This is set 1 of 4.
> 
> HP BIOS Configuration driver purpose is to provide a driver supporting
> the latest sysfs class firmware attributes framework allowing the user
> to change BIOS settings and security solutions on HP Inc.’s commercial
> notebooks.
> 
> Many features of HP Commercial PC’s can be managed using Windows
> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> Enterprise Management (WBEM) that provides a standards-based interface
> for changing and monitoring system settings.  HP BISOCFG driver provides
> a native Linux solution and the exposed features facilitates the
> migration to Linux environments.
> 
> The Linux security features to be provided in hp-bioscfg driver enables
> managing the BIOS settings and security solutions via sysfs, a virtual
> filesystem that can be used by user-mode applications.   The new
> documentation cover features such Secure Platform Management, Sure
> Admin, and Sure Start.  Each section provides security feature
> description and identifies sysfs directories and files exposed by
> the driver.
> 
> Many HP Commercial PC’s include a feature called Secure Platform
> Management (SPM), which replaces older password-based BIOS settings
> management with public key cryptography. PC secure product management
> begins when a target system is provisioned with cryptographic keys
> that are used to ensure the integrity of communications between system
> management utilities and the BIOS.
> 
> HP Commercial PC’s have several BIOS settings that control its behaviour
> and capabilities, many of which are related to security. To prevent
> unauthorized changes to these settings, the system can be configured
> to use a Sure Admin cryptographic signature-based authorization string
> that the BIOS will use to verify authorization to modify the setting.
> 
> Signed-off-by: Jorge Lopez <jorge.lopez2@hp.com>
> 
> ---
> Based on the latest platform-drivers-x86.git/for-next
> ---
>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
>  3 files changed, 1477 insertions(+)
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> 
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> new file mode 100644
> index 000000000000..f0c919bf3ab0
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> @@ -0,0 +1,285 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to methods under BIOS interface GUID
> + * for use with hp-bioscfg driver.
> + *
> + *  Copyright (c) 2022 Hewlett-Packard Inc.
> + */
> +
> +#include <linux/wmi.h>
> +#include "bioscfg.h"
> +
> +#define SET_DEFAULT_VALUES_METHOD_ID	0x02
> +#define SET_BIOS_DEFAULTS_METHOD_ID	0x03
> +#define SET_ATTRIBUTE_METHOD_ID		0x04
> +
> +/*
> + * set_attribute() - Update an attribute value
> + * @a_name: The attribute name
> + * @a_value: The attribute value
> + *
> + * Sets an attribute to new value
> + */
> +int hp_set_attribute(const char *a_name, const char *a_value)
> +{
> +	size_t security_area_size;
> +	size_t a_name_size, a_value_size;
> +	u16 *buffer = NULL;
> +	u16 *start = NULL;
> +	int  buffer_size;

You have 2 spaces between int and buffer_size here, please drop
one.


> +	int ret;
> +	int instance;
> +	char *auth_empty_value = " ";
> +
> +	mutex_lock(&bioscfg_drv.mutex);
> +	if (!bioscfg_drv.bios_attr_wdev) {
> +		ret = -ENODEV;
> +		goto out_set_attribute;
> +	}
> +
> +	instance = get_password_instance_for_type(SETUP_PASSWD);
> +	if (instance < 0)
> +		goto out_set_attribute;
> +
> +	if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> +		strncpy(bioscfg_drv.password_data[instance].current_password,
> +			auth_empty_value,
> +			sizeof(bioscfg_drv.password_data[instance].current_password));

strncpy does not guarantee 0 termination of the destination buffer,
please use strscpy.

> +
> +	a_name_size = calculate_string_buffer(a_name);
> +	a_value_size = calculate_string_buffer(a_value);
> +	security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> +	buffer_size = a_name_size + a_value_size + security_area_size;
> +
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer) {
> +		ret = -ENOMEM;
> +		goto out_set_attribute;
> +	}
> +
> +	/* build variables to set */
> +	start = buffer;
> +	start = ascii_to_utf16_unicode(start, a_name);
> +	if (!start)
> +		goto out_set_attribute;
> +
> +	start = ascii_to_utf16_unicode(start, a_value);
> +	if (!start)
> +		goto out_set_attribute;
> +
> +	populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> +	ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> +
> +
> +out_set_attribute:
> +	kfree(buffer);
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	return ret;
> +}
> +
> +/*
> + * hp_wmi_perform_query
> + *
> + * query:	The commandtype (enum hp_wmi_commandtype)
> + * write:	The command (enum hp_wmi_command)
> + * buffer:	Buffer used as input and/or output
> + * insize:	Size of input buffer
> + * outsize:	Size of output buffer
> + *
> + * returns zero on success
> + *         an HP WMI query specific error code (which is positive)
> + *         -EINVAL if the query was not successful at all
> + *         -EINVAL if the output buffer size exceeds buffersize
> + *
> + * Note: The buffersize must at least be the maximum of the input and output
> + *       size. E.g. Battery info query is defined to have 1 byte input
> + *       and 128 byte output. The caller would do:
> + *       buffer = kzalloc(128, GFP_KERNEL);
> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> + */
> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> +{
> +	struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	struct bios_return *bios_return;
> +	union acpi_object *obj = NULL;
> +	struct bios_args *args = NULL;
> +	int mid, actual_insize, actual_outsize;
> +	size_t bios_args_size;
> +	int ret;
> +
> +	mid = encode_outsize_for_pvsz(outsize);
> +	if (WARN_ON(mid < 0))
> +		return mid;
> +
> +	actual_insize = insize;
> +	bios_args_size = struct_size(args, data, insize);
> +	args = kmalloc(bios_args_size, GFP_KERNEL);
> +	if (!args)
> +		return -ENOMEM;
> +
> +	input.length = bios_args_size;
> +	input.pointer = args;
> +
> +	args->signature = 0x55434553;
> +	args->command = command;
> +	args->commandtype = query;
> +	args->datasize = insize;
> +	memcpy(args->data, buffer, flex_array_size(args, data, insize));
> +
> +	ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> +	bioscfg_drv.last_wmi_status = ret;
> +	if (ret)
> +		goto out_free;
> +
> +	obj = output.pointer;
> +	if (!obj) {
> +		ret = -EINVAL;
> +		goto out_free;
> +	}
> +

You need to check the type of obj here before dereferencing
obj as if it is a buffer.

> +	bios_return = (struct bios_return *)obj->buffer.pointer;
> +	ret = bios_return->return_code;
> +	bioscfg_drv.last_wmi_status = ret;
> +	if (ret) {
> +		if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> +		    ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> +			pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> +		goto out_free;
> +	}
> +
> +	/* Ignore output data of zero size */
> +	if (!outsize)
> +		goto out_free;
> +
> +	actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> +	memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> +	memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> +
> +out_free:
> +	kfree(obj);
> +	kfree(args);
> +	return ret;
> +}
> +
> +/*
> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> + *
> + * @p:   Unicode buffer address
> + * @str: string to convert to unicode
> + *
> + * Returns a void pointer to the buffer containing unicode string
> + */
> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> +{
> +	int len = strlen(str);
> +	int ret;
> +
> +	/*
> +	 * Add null character when reading an empty string
> +	 */
> +	if (len == 0) {
> +		*p++ = 2;
> +		*p++ = (u8)0x00;
> +		return p;

This does not match with calculate_string_buffer() which will
return 2 for a 0 length string while you are using 4 bytes here.

I guess this may also be why you need to use " " for
auth_empty_value above, so as to avoid this bug.


> +	}
> +	*p++ = len * 2;
> +	ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);
> +
> +	if (ret < 0) {
> +		dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");
> +		goto ascii_to_utf16_unicode_out;

You have an error here, but you don't return an error at the end of
this function.

Please for version 5 do the following:

1. Add a preparation patch which moves populate_string_buffer()
and calculate_string_buffer() from
drivers/platform/x86/dell/dell-wmi-sysman/sysman.c to
drivers/platform/x86/wmi.c

Renaming them to:

size_t wmi_utf16_str_size(const char *str);
ssize_t wmi_str_to_utf16_str(u16 *buffer, size_t buffer_len, const char *str);

(adding these prototypes to include/linux/wmi.h)

and make the dell-wmi-sysman code use these new helpers

2. Also use these new helpers in your own code instead
of your own ascii_to_utf16_unicode() function

> +	}
> +
> +	if ((ret * sizeof(u16)) > U16_MAX) {
> +		dev_err(bioscfg_drv.class_dev, "Error string too long\n");
> +		goto ascii_to_utf16_unicode_out;
> +	}
> +
> +ascii_to_utf16_unicode_out:
> +	p += len;
> +	return p;
> +}
> +
> +/*
> + * hp_wmi_set_bios_setting - Set setting's value in BIOS
> + *
> + * @input_buffer: Input buffer address
> + * @input_size:   Input buffer size
> + *
> + * Returns: Count of unicode characters written to BIOS if successful, otherwise
> + *		-ENOMEM unable to allocate memory
> + *		-EINVAL buffer not allocated or too small
> + */
> +int hp_wmi_set_bios_setting(void *input_buffer, int input_size)
> +{
> +	union acpi_object *obj;
> +	struct acpi_buffer input = {input_size, input_buffer};
> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> +	int ret = 0;
> +
> +	ret = wmi_evaluate_method(HP_WMI_SET_BIOS_SETTING_GUID, 0, 1, &input, &output);
> +
> +	obj = output.pointer;
> +	if (!obj)
> +		return -EINVAL;
> +
> +	if (obj->type != ACPI_TYPE_INTEGER)
> +		ret = -EINVAL;
> +
> +	ret = obj->integer.value;
> +
> +	kfree(obj);
> +	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)
> +{
> +	return -EOPNOTSUPP;
> +}

This function is not used anywhere, please drop it.

> +
> +static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
> +{
> +	mutex_lock(&bioscfg_drv.mutex);
> +	bioscfg_drv.bios_attr_wdev = wdev;
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	return 0;
> +}
> +
> +static void bios_attr_set_interface_remove(struct wmi_device *wdev)
> +{
> +	mutex_lock(&bioscfg_drv.mutex);
> +	bioscfg_drv.bios_attr_wdev = NULL;
> +	mutex_unlock(&bioscfg_drv.mutex);
> +}
> +
> +static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
> +	{ .guid_string = HP_WMI_BIOS_GUID},
> +	{ },
> +};
> +static struct wmi_driver bios_attr_set_interface_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME
> +	},
> +	.probe = bios_attr_set_interface_probe,
> +	.remove = bios_attr_set_interface_remove,
> +	.id_table = bios_attr_set_interface_id_table,
> +};
> +
> +int init_bios_attr_set_interface(void)
> +{
> +	return wmi_driver_register(&bios_attr_set_interface_driver);
> +}
> +
> +void exit_bios_attr_set_interface(void)
> +{
> +	wmi_driver_unregister(&bios_attr_set_interface_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> new file mode 100644
> index 000000000000..4409481f84f2
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> @@ -0,0 +1,671 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * Definitions for kernel modules using hp_bioscfg driver
> + *
> + *  Copyright (c) 2022 HP Development Company, L.P.
> + */
> +
> +#ifndef _HP_BIOSCFG_H_
> +#define _HP_BIOSCFG_H_
> +
> +#include <linux/wmi.h>
> +#include <linux/types.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/capability.h>
> +#include <linux/nls.h>
> +
> +
> +#define DRIVER_NAME	"hp-bioscfg"
> +
> +#define MAX_BUFF		512
> +#define MAX_KEY_MOD		256
> +#define MAX_PASSWD_SIZE		64
> +#define MAX_MESSAGE_SIZE        256
> +
> +#define SPM_STR_DESC	"Secure Platform Management"
> +#define SPM_STR		"SPM"
> +#define SURE_START_DESC "Sure Start"
> +#define SURE_START_STR  "Sure_Start"
> +#define SURE_ADMIN_DESC "Sure Admin"
> +#define SURE_ADMIN_STR  "Sure_Admin"
> +#define SETUP_PASSWD	"Setup Password"
> +#define POWER_ON_PASSWD	"Power-On Password"
> +
> +#define LANG_CODE_STR		"en_US.UTF-8"
> +#define SCHEDULE_POWER_ON	"Scheduled Power-On"
> +
> +/* Sure Admin Functions */
> +
> +#define UTF_PREFIX	((unsigned char *)"<utf-16/>")
> +#define BEAM_PREFIX	((unsigned char *)"<BEAM/>")
> +
> +/* mechanism - Authentication attribute */
> +
> +#define MAX_MECHANISM_TYPES 3
> +
> +enum mechanism_values {
> +	PASSWORD	= 0x00,
> +	NOT_PROVISION   = 0x00,
> +	SIGNING_KEY	= 0x01,
> +	ENDORSEMENT_KEY = 0x02
> +};
> +
> +static const char * const spm_mechanism_types[] = {
> +	"not provision",
> +	"signing-key",
> +	"endorsement-key"
> +};
> +
> +static const char * const passwd_mechanism_types[] = {
> +	"password",
> +};
> +
> +/* roles - Authentication attribute */
> +enum role_values {
> +	BIOS_ADMIN	= 0x00,
> +	POWER_ON	= 0x01,
> +	BIOS_SPM	= 0x02
> +};
> +
> +static const char * const role_type[] = {
> +	"bios-admin",
> +	"power-on",
> +	"enhanced-bios-auth"
> +};
> +
> +
> +#define HP_WMI_BIOS_GUID		"5FB7F034-2C63-45e9-BE91-3D44E2C707E4"
> +
> +#define HP_WMI_BIOS_STRING_GUID		"988D08E3-68F4-4c35-AF3E-6A1B8106F83C"
> +#define HP_WMI_BIOS_INTEGER_GUID	"8232DE3D-663D-4327-A8F4-E293ADB9BF05"
> +#define HP_WMI_BIOS_ENUMERATION_GUID	"2D114B49-2DFB-4130-B8FE-4A3C09E75133"
> +#define HP_WMI_BIOS_ORDERED_LIST_GUID	"14EA9746-CE1F-4098-A0E0-7045CB4DA745"
> +#define HP_WMI_BIOS_PASSWORD_GUID	"322F2028-0F84-4901-988E-015176049E2D"
> +#define HP_WMI_SET_BIOS_SETTING_GUID	"1F4C91EB-DC5C-460b-951D-C7CB9B4B8D5E"
> +
> +enum hp_wmi_spm_commandtype {
> +	HPWMI_SECUREPLATFORM_GET_STATE  = 0x10,
> +	HPWMI_SECUREPLATFORM_SET_KEK	= 0x11,
> +	HPWMI_SECUREPLATFORM_SET_SK	= 0x12,
> +};
> +
> +enum hp_wmi_surestart_commandtype {
> +	HPWMI_SURESTART_GET_LOG_COUNT	= 0x01,
> +	HPWMI_SURESTART_GET_LOG		= 0x02,
> +};
> +
> +enum hp_wmi_command {
> +	HPWMI_READ		= 0x01,
> +	HPWMI_WRITE		= 0x02,
> +	HPWMI_ODM		= 0x03,
> +	HPWMI_SURESTART		= 0x20006,
> +	HPWMI_GM		= 0x20008,
> +	HPWMI_SECUREPLATFORM	= 0x20010,
> +};
> +
> +struct bios_return {
> +	u32 sigpass;
> +	u32 return_code;
> +};
> +
> +enum hp_return_value {
> +	HPWMI_RET_WRONG_SIGNATURE	= 0x02,
> +	HPWMI_RET_UNKNOWN_COMMAND	= 0x03,
> +	HPWMI_RET_UNKNOWN_CMDTYPE	= 0x04,
> +	HPWMI_RET_INVALID_PARAMETERS	= 0x05,
> +};
> +
> +enum wmi_error_values {
> +	SUCCESS			= 0x00,
> +	CMD_FAILED			= 0x01,
> +	INVALID_SIGN			= 0x02,
> +	INVALID_CMD_VALUE		= 0x03,
> +	INVALID_CMD_TYPE		= 0x04,
> +	INVALID_DATA_SIZE		= 0x05,
> +	INVALID_CMD_PARAM		= 0x06,
> +	ENCRYP_CMD_REQUIRED		= 0x07,
> +	NO_SECURE_SESSION		= 0x08,
> +	SECURE_SESSION_FOUND		= 0x09,
> +	SECURE_SESSION_FAILED		= 0x0A,
> +	AUTH_FAILED			= 0x0B,
> +	INVALID_BIOS_AUTH		= 0x0E,
> +	NONCE_DID_NOT_MATCH		= 0x18,
> +	GENERIC_ERROR			= 0x1C,
> +	BIOS_ADMIN_POLICY_NOT_MET	= 0x28,
> +	BIOS_ADMIN_NOT_SET		= 0x38,
> +	P21_NO_PROVISIONED		= 0x1000,
> +	P21_PROVISION_IN_PROGRESS	= 0x1001,
> +	P21_IN_USE			= 0x1002,
> +	HEP_NOT_ACTIVE			= 0x1004,
> +	HEP_ALREADY_SET		= 0x1006,
> +	HEP_CHECK_STATE		= 0x1007
> +};
> +
> +enum spm_features {
> +	HEP_ENABLED		= 0x01,
> +	PLATFORM_RECOVERY	= 0x02,
> +	ENHANCED_BIOS_AUTH_MODE	= 0x04
> +};
> +
> +
> +/*
> + * struct bios_args buffer is dynamically allocated.  New WMI command types
> + * were introduced that exceeds 128-byte data size.  Changes to handle
> + * the data size allocation scheme were kept in hp_wmi_perform_qurey function.
> + */
> +struct bios_args {
> +	u32 signature;
> +	u32 command;
> +	u32 commandtype;
> +	u32 datasize;
> +	u8 data[];
> +};
> +
> +
> +#pragma pack(1)
> +struct secureplatform_provisioning_data {
> +	u8 state;
> +	u8 version[2];
> +	u8 reserved1;
> +	u32 features;
> +	u32 nonce;
> +	u8 reserved2[28];
> +	u8 sk_mod[MAX_KEY_MOD];
> +	u8 kek_mod[MAX_KEY_MOD];
> +};
> +
> +#pragma pack()
> +
> +
> +struct string_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 current_value[MAX_BUFF];
> +	u8 new_value[MAX_BUFF];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 min_length;
> +	u32 max_length;
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct integer_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u32 current_value;
> +	u32 new_value;
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 lower_bound;
> +	u32 upper_bound;
> +	u32 scalar_increment;
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct enumeration_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u8 current_value[MAX_BUFF];
> +	u8 new_value[MAX_BUFF];
> +	u32 size;
> +	u8 possible_values[MAX_BUFF];
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct ordered_list_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 current_value[MAX_BUFF];
> +	u8 new_value[MAX_BUFF];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 size;
> +	u8 elements[MAX_BUFF];
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct password_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 current_password[MAX_PASSWD_SIZE];
> +	u8 new_password[MAX_PASSWD_SIZE];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 min_password_length;
> +	u32 max_password_length;
> +	u32 encoding_size;
> +	u8 supported_encoding[MAX_BUFF];
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 is_enabled;
> +
> +	// 'bios-admin' 'power-on'
> +	u32 role;
> +
> +	//'password'
> +	u32 mechanism;
> +	u32 type;
> +};
> +
> +struct secure_platform_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +
> +	u8 *endorsement_key;
> +	u8 *signing_key;
> +
> +	u32 is_enabled;
> +	u32 mechanism;
> +	u32 type;
> +};
> +
> +struct bioscfg_priv {
> +	struct wmi_device *password_attr_wdev;
> +	struct wmi_device *bios_attr_wdev;
> +	struct kset *authentication_dir_kset;
> +	struct kset *main_dir_kset;
> +	struct device *class_dev;
> +	struct string_data *string_data;
> +	u32 string_instances_count;
> +	struct integer_data *integer_data;
> +	u32 integer_instances_count;
> +	struct enumeration_data *enumeration_data;
> +	u32 enumeration_instances_count;
> +	struct ordered_list_data *ordered_list_data;
> +	u32 ordered_list_instances_count;
> +	struct password_data *password_data;
> +	u32 password_instances_count;
> +
> +	struct kobject *sure_start_attr_kobj;
> +	struct kobject *sure_admin_attr_kobj;
> +	struct secure_platform_data spm_data;
> +
> +	int  last_wmi_status;
> +	bool pending_reboot;
> +	struct mutex mutex;
> +};
> +
> +/* global structure used by multiple WMI interfaces */
> +extern struct bioscfg_priv bioscfg_drv;
> +
> +enum hp_wmi_data_type {
> +	HPWMI_STRING_TYPE		= 0x00,
> +	HPWMI_INTEGER_TYPE		= 0x01,
> +	HPWMI_ENUMERATION_TYPE		= 0x02,
> +	HPWMI_ORDERED_LIST_TYPE		= 0x03,
> +	HPWMI_PASSWORD_TYPE		= 0x04,
> +	HPWMI_SECURE_PLATFORM_TYPE	= 0x05,
> +	HPWMI_SURE_START_TYPE		= 0x06,
> +	HPWMI_SURE_ADMIN_TYPE           = 0x07,
> +};
> +
> +enum hp_wmi_data_elements {
> +
> +	/* Common elements */
> +	NAME = 0,
> +	VALUE = 1,
> +	PATH = 2,
> +	IS_READONLY = 3,
> +	DISPLAY_IN_UI = 4,
> +	REQUIRES_PHYSICAL_PRESENCE = 5,
> +	SEQUENCE = 6,
> +	PREREQUISITE_SIZE = 7,
> +	PREREQUISITES = 8,
> +	SECURITY_LEVEL = 9,
> +
> +	/* String elements */
> +	STR_MIN_LENGTH = 10,
> +	STR_MAX_LENGTH = 11,
> +
> +	/* Integer elements */
> +	INT_LOWER_BOUND = 10,
> +	INT_UPPER_BOUND = 11,
> +	INT_SCALAR_INCREMENT = 12,
> +
> +	/* Enumeration elements */
> +	ENUM_CURRENT_VALUE = 10,
> +	ENUM_SIZE = 11,
> +	ENUM_POSSIBLE_VALUES = 12,
> +
> +	/* Ordered list elements */
> +	ORD_LIST_SIZE = 10,
> +	ORD_LIST_ELEMENTS = 11,
> +
> +	/* Password elements */
> +	PSWD_MIN_LENGTH = 10,
> +	PSWD_MAX_LENGTH = 11,
> +	PSWD_SIZE = 12,
> +	PSWD_SUPPORTED_ENCODING = 13,
> +	PSWD_IS_SET = 14
> +};
> +
> +
> +static const int hp_wmi_elements_count[] = {
> +	12,   // string
> +	13,   // integer
> +	13,   // enumeration
> +	12,   // ordered list
> +	15    // password
> +};
> +
> +#define get_instance_id(type)							\
> +static int get_##type##_instance_id(struct kobject *kobj)			\
> +{										\
> +	int i; \
> +								\
> +	for (i = 0; i <= bioscfg_drv.type##_instances_count; i++) { \
> +		if (!(strcmp(kobj->name, bioscfg_drv.type##_data[i].attribute_name))) \
> +			return i;						\
> +	}									\
> +	return -EIO;								\
> +}
> +
> +#define get_instance_id_for_attribute(type)			\
> +static int get_instance_id_for_##type(char *attr_name)	        \
> +{										\
> +	int i;									\
> +										\
> +	for (i = 0; i < bioscfg_drv.type##_instances_count; i++) {		\
> +		if (strcmp(bioscfg_drv.type##_data[i].attribute_name, attr_name) == 0)						\
> +			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", bioscfg_drv.type##_data[i].name);	\

Please use sysfs_emit instead of sprintf for this and all the other _show() functions.

> +	return 0;								\
> +}
> +/* There is no need to keep track of default and current values
> + * separately
> + */
> +#define attribute_s_default_property_show(name, type, new_name)			\
> +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", bioscfg_drv.type##_data[i].new_name);	\
> +	return 0;								\
> +}
> +
> +#define attribute_n_default_property_show(name, type, new_name)			\
> +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", bioscfg_drv.type##_data[i].new_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", bioscfg_drv.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 = NULL;								\
> +	char *attr_value = NULL;						\
> +	char *attr_name = NULL;							\
> +	int i;									\
> +	int ret = -EIO;								\
> +										\
> +	attr_name = kstrdup(kobj->name, GFP_KERNEL);				\
> +	if (!attr_name)								\
> +		return -ENOMEM;							\

Since you don't modify attr_name (unlike attr_value) there is no need
to make a local copy, just use kobj->name directly instead of
the copy stored in attr_name.

> +	attr_value = kstrdup(buf, GFP_KERNEL);					\
> +	if (!attr_value)							\
> +		return -ENOMEM;							\
> +										\
> +	p = memchr(attr_value, '\n', count);					\
> +	if (p != NULL)								\
> +		*p = '\0';							\
> +										\
> +	i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		ret = validate_##type##_input(i, attr_value);			\
> +	if (!ret)								\
> +		ret = hp_set_attribute(attr_name, attr_value);			\
> +	if (!ret)								\
> +		update_##type##_value(i);					\
> +										\
> +	clear_all_passwords();							\

Why ?

At a minimum add a comment explaining this.

> +	kfree(attr_name);							\
> +	kfree(attr_value);							\
> +										\
> +	return ret ? ret : count;						\
> +}
> +
> +#define attribute_spm_n_property_show(name, type)				\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
> +{									\
> +	return sprintf(buf, "%d\n", bioscfg_drv.type##_data.name);\
> +}
> +
> +#define attribute_spm_s_property_show(name, type)				\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
> +{									\
> +	return sprintf(buf, "%s\n", bioscfg_drv.type##_data.name);		\
> +}
> +
> +#define check_property_type(attr, prop, valuetype)\
> +	(attr##_obj[prop].type != valuetype)
> +
> +#define HPWMI_BINATTR_RW(_group, _name, _size)	\
> +static struct bin_attribute _group##_##_name =	\
> +__BIN_ATTR(_name, 0444 | 0200, _group##_##_name##_read, _group##_##_name##_write, _size)
> +
> +/*
> + * Prototypes
> + */
> +union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string);
> +int get_instance_count(const char *guid_string);
> +void strlcpy_attr(char *dest, char *src);
> +void update_attribute_permissions(u32 isReadOnly, struct kobj_attribute *current_val);
> +void friendly_user_name_update(char *path, const char *attr_name,
> +				char *attr_display, int attr_size);
> +
> +/* String attributes */
> +int populate_string_buffer_data(union acpi_object *str_obj,
> +			 int instance_id,
> +			 struct kobject *attr_name_kobj);
> +int populate_string_elements_from_buffer(union acpi_object *string_obj,
> +					 int instance_id,
> +					 enum hp_wmi_data_type type);
> +int alloc_string_data(void);
> +void exit_string_attributes(void);
> +int populate_string_package_data(union acpi_object *str_obj,
> +				 int instance_id,
> +				 struct kobject *attr_name_kobj);
> +int populate_string_elements_from_package(union acpi_object *str_obj,
> +						  int instance_id,
> +						  enum hp_wmi_data_type type);
> +
> +/* Integer attributes */
> +int populate_integer_buffer_data(union acpi_object *integer_obj,
> +			  int instance_id,
> +			  struct kobject *attr_name_kobj);
> +int populate_integer_elements_from_buffer(union acpi_object *integer_obj,
> +					  int instance_id,
> +					  enum hp_wmi_data_type type);
> +int alloc_integer_data(void);
> +void exit_integer_attributes(void);
> +int populate_integer_package_data(union acpi_object *integer_obj,
> +				  int instance_id,
> +				  struct kobject *attr_name_kobj);
> +int populate_integer_elements_from_package(union acpi_object *integer_obj,
> +						  int instance_id,
> +						  enum hp_wmi_data_type type);
> +
> +/* Enumeration attributes */
> +int populate_enumeration_buffer_data(union acpi_object *enum_obj,
> +			      int instance_id,
> +			      struct kobject *attr_name_kobj);
> +int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
> +					      int instance_id,
> +					      enum hp_wmi_data_type type);
> +int alloc_enumeration_data(void);
> +void exit_enumeration_attributes(void);
> +int populate_enumeration_package_data(union acpi_object *enum_obj,
> +				      int instance_id,
> +				      struct kobject *attr_name_kobj);
> +int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
> +					       int instance_id,
> +					       enum hp_wmi_data_type type);
> +
> +/* Ordered list */
> +int populate_ordered_list_buffer_data(union acpi_object *order_obj, int instance_id,
> +				      struct kobject *attr_name_kobj);
> +int populate_ordered_list_elements_from_buffer(union acpi_object *order_obj,
> +					       int instance_id,
> +					       enum hp_wmi_data_type
> +					       type);
> +int alloc_ordered_list_data(void);
> +void exit_ordered_list_attributes(void);
> +int populate_ordered_list_package_data(union acpi_object *order_obj,
> +				       int instance_id,
> +				       struct kobject *attr_name_kobj);
> +int populate_ordered_list_elements_from_package(union acpi_object *order_obj,
> +						int instance_id,
> +						enum hp_wmi_data_type type);
> +
> +/* Password authentication attributes */
> +int populate_password_buffer_data(union acpi_object *password_obj,
> +			   int instance_id,
> +			   struct kobject *attr_name_kobj);
> +int populate_password_elements_from_buffer(union acpi_object *password_obj,
> +					   int instance_id,
> +					   enum hp_wmi_data_type type);
> +int populate_password_package_data(union acpi_object *password_obj, int instance_id,
> +				   struct kobject *attr_name_kobj);
> +int populate_password_elements_from_package(union acpi_object *password_obj,
> +					   int instance_id,
> +					    enum hp_wmi_data_type type);
> +int alloc_password_data(void);
> +int alloc_secure_platform_data(void);
> +void exit_password_attributes(void);
> +void exit_secure_platform_attributes(void);
> +int populate_secure_platform_data(struct kobject *attr_name_kobj);
> +int password_is_set(const char *auth);
> +int check_spm_is_enabled(void);
> +int wmi_error_and_message(int error_code, char *message);
> +int hp_wmi_set_bios_setting(void *input_buffer, int input_size);
> +int hp_wmi_perform_query(int query, enum hp_wmi_command command,
> +				void *buffer, int insize, int outsize);
> +
> +/* Sure Start attributes */
> +void exit_sure_start_attributes(void);
> +int populate_sure_start_data(struct kobject *attr_name_kobj);
> +
> +/* Sure Admin Attributes */
> +void exit_sure_admin_attributes(void);
> +int populate_sure_admin_data(struct kobject *attr_name_kobj);
> +int hp_set_attribute(const char *a_name, const char *a_value);
> +int hp_set_attribute_with_payload(const char *a_name,
> +				  const char *a_value,
> +				  const char *auth_payload);
> +int update_attribute_value(char *attr_name, char *attr_value);
> +int hp_bios_settings_fill_buffer(void);
> +int hp_bios_settings_free_buffer(void);
> +int hp_bios_settings_realloc_buffer(char **buf, int *buf_size,
> +					   int *alloc_size);
> +int append_read_string_attributes(char *buf, int alloc_size,
> +					int instance,
> +					enum hp_wmi_data_type type);
> +int append_read_integer_attributes(char *buf, int alloc_size,
> +					 int instance,
> +					 enum hp_wmi_data_type type);
> +int append_read_enumeration_attributes(char *buf, int alloc_size,
> +					     int instance,
> +					     enum hp_wmi_data_type type);
> +int append_read_ordered_list_attributes(char *buf, int alloc_size,
> +					      int instance,
> +					      enum hp_wmi_data_type type);
> +int append_read_password_attributes(char *buf, int alloc_size,
> +					 int instance,
> +					 enum hp_wmi_data_type type);
> +int append_read_settings(enum hp_wmi_data_type type, char **buf,
> +			      int *buf_size, int *alloc_size);
> +int append_read_attributes(char **buf, int alloc_size,
> +				 int instance, enum hp_wmi_data_type type);
> +int set_bios_defaults(u8 defType);
> +int get_password_instance_for_type(const char *name);
> +int clear_all_passwords(void);
> +int clear_passwords(const int instance);
> +void exit_bios_attr_set_interface(void);
> +int init_bios_attr_set_interface(void);
> +size_t calculate_string_buffer(const char *str);
> +size_t calculate_security_buffer(const char *authentication);
> +void populate_security_buffer(u16 *buffer, const char *authentication);
> +ssize_t populate_string_buffer(u16 *buffer, size_t buffer_len, const char *str);
> +int set_new_password(const char *password_type, const char *new_password);
> +int init_bios_attr_pass_interface(void);
> +void exit_bios_attr_pass_interface(void);
> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str);
> +int get_integer_from_buffer(int **buffer, int *integer);
> +int get_string_from_buffer(u16 **buffer, char **str);
> +int convert_hexstr_to_str(char **hex, int input_len, char **str, int *len);
> +int convert_hexstr_to_int(char *str, int *int_value);
> +inline int encode_outsize_for_pvsz(int outsize);

Please drop the inline here, since this is just a function prototype it cannot
be inlined.

And please also drop the inline from the actual implementation, since
that is only used in other .c files.

> +
> +#endif
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> new file mode 100644
> index 000000000000..e67e7c397c12
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> @@ -0,0 +1,521 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to enumeration type attributes under
> + * BIOS Enumeration GUID for use with hp-bioscfg driver.
> + *
> + *  Copyright (c) 2022 HP Development Company, L.P.
> + */
> +
> +#include "bioscfg.h"
> +
> +get_instance_id(enumeration);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id = get_enumeration_instance_id(kobj);
> +	union acpi_object *obj = NULL;
> +	ssize_t ret;
> +
> +	if (instance_id < 0)
> +		return -EIO;
> +
> +	/* need to use specific instance_id and guid combination to get right data */
> +	obj = get_wmiobj_pointer(instance_id, HP_WMI_BIOS_ENUMERATION_GUID);
> +	if (!obj)
> +		return -EIO;

Why get this obj if you are not using it at all ? The attribute_property_store()
macro updates bioscfg_drv.enumeration_data[instance_id].current_value on success,
so I believe this function can just 

> +
> +	ret = snprintf(buf, PAGE_SIZE, "%s\n",
> +		       bioscfg_drv.enumeration_data[instance_id].current_value);

please use sysfs_emit for this 

> +
> +	kfree(obj);
> +	return ret;
> +}
> +
> +
> +/*
> + * validate_enumeration_input() -
> + * Validate input of current_value against possible values
> + *
> + * @instance_id: The instance on which input is validated
> + * @buf: Input value
> + */
> +static int validate_enumeration_input(int instance_id, const char *buf)
> +{
> +	char *options = NULL;
> +	char *p;
> +	int ret = 0;
> +	int found = 0;
> +
> +	options = kstrdup(bioscfg_drv.enumeration_data[instance_id].possible_values,
> +			  GFP_KERNEL);
> +
> +	if (!options) {
> +		ret = -ENOMEM;
> +		goto exit_validate_enum_input;
> +	}
> +
> +	/* Is it a read only attribute */
> +	if (bioscfg_drv.enumeration_data[instance_id].is_readonly) {
> +		ret = -EIO;
> +		goto exit_validate_enum_input;
> +	}

Please move this check to before the kstrdup and just 
directly return -EIO; instead of doing the goto.

> +
> +	while ((p = strsep(&options, ";")) != NULL) {
> +		if (!*p)
> +			continue;
> +
> +		if (!strcasecmp(p, buf)) {
> +			found = 1;
> +			break;
> +		}
> +	}
> +
> +	if (!found) {
> +		ret = -EINVAL;
> +		goto exit_validate_enum_input;
> +	}
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].new_value,
> +		buf,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].new_value));

Why store a copy of buf in new_value?  This function is only called from
the attribute_property_store() with attr_value as buf parameter.

You can just also pass attr_value to update_##type##_value()
and then have update_enumeration_value() directly store attr_value
in current_value.

Doing things this way allows removing new_value from struct enumeration_data
all together resulting in a nice reduction in memory usage.

> +	/*
> +	 * set pending reboot flag depending on
> +	 * "RequiresPhysicalPresence" value
> +	 */
> +	if (bioscfg_drv.enumeration_data[instance_id].requires_physical_presence)
> +		bioscfg_drv.pending_reboot = TRUE;
> +
> +exit_validate_enum_input:
> +	kfree(options);
> +	return ret;
> +}
> +
> +static void update_enumeration_value(int instance_id)
> +{
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> +		bioscfg_drv.enumeration_data[instance_id].new_value,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> +}
> +
> +
> +attribute_s_property_show(display_name_language_code, enumeration);
> +static struct kobj_attribute enumeration_display_langcode =
> +		__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, enumeration);
> +static struct kobj_attribute  enumeration_display_name =
> +		__ATTR_RO(display_name);
> +
> +attribute_property_store(current_value, enumeration);
> +static struct kobj_attribute enumeration_current_val =
> +	__ATTR_RW_MODE(current_value, 0600);
> +
> +attribute_s_property_show(possible_values, enumeration);
> +static struct kobj_attribute  enumeration_poss_val =
> +		__ATTR_RO(possible_values);
> +
> +static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	return sprintf(buf, "enumeration\n");
> +}
> +static struct kobj_attribute enumeration_type =
> +		__ATTR_RO(type);
> +
> +static struct attribute *enumeration_attrs[] = {
> +	&enumeration_display_langcode.attr,
> +	&enumeration_display_name.attr,
> +	&enumeration_current_val.attr,
> +	&enumeration_poss_val.attr,
> +	&enumeration_type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group enumeration_attr_group = {
> +	.attrs = enumeration_attrs,
> +};
> +
> +int alloc_enumeration_data(void)
> +{
> +	int ret = 0;
> +
> +	bioscfg_drv.enumeration_instances_count =
> +		get_instance_count(HP_WMI_BIOS_ENUMERATION_GUID);
> +
> +	bioscfg_drv.enumeration_data = kcalloc(bioscfg_drv.enumeration_instances_count,
> +					sizeof(struct enumeration_data), GFP_KERNEL);
> +	if (!bioscfg_drv.enumeration_data) {
> +		bioscfg_drv.enumeration_instances_count = 0;
> +		ret = -ENOMEM;
> +	}
> +	return ret;
> +}
> +
> +/*
> + * populate_enumeration_package_data() -
> + * Populate all properties of an instance under enumeration attribute
> + *
> + * @enum_obj: ACPI object with enumeration data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + */
> +int populate_enumeration_package_data(union acpi_object *enum_obj, int instance_id,
> +			struct kobject *attr_name_kobj)
> +{
> +	char *str_value = NULL;
> +	int str_len;
> +	int ret = 0;
> +
> +	bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
> +	bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
> +
> +	ret = convert_hexstr_to_str(&(enum_obj[NAME].string.pointer),
> +				    enum_obj[NAME].string.length,
> +				    &str_value, &str_len);
> +	if (ACPI_FAILURE(ret)) {
> +		pr_warn("Failed to populate enumeration package data. Error [0%0x]\n", ret);
> +		kfree(str_value);
> +		return ret;
> +	}

You have already done this convert_hexstr_to_str call in
hp_init_bios_attributes() and used it for the name of the passed in
struct kobject *attr_name_kobj, so you can just use attr_name_kobj->name
here, as you already do in the friendly_user_name_update() call below?

Also you use kobj->name in the get_##type##_instance_id() macro, and the
only reason why the enumeration_data[instance_id].attribute_name field
is necessary is for that function.

So dropping the above call and using kobj->name to intialize attribute_name
and display_name seems to make sense here ?




> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
> +		str_value,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
> +		str_value,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +
> +	kfree(str_value);
> +	str_value = NULL;

And then you can also drop this. Note there is no need to set str_value to NULL
here regardless since it is a local variable which will disappear when the
function ends.

> +
> +	populate_enumeration_elements_from_package(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
> +	update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
> +				    &enumeration_current_val);
> +	friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
> +				  attr_name_kobj->name,
> +				   bioscfg_drv.enumeration_data[instance_id].display_name,
> +				   sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +	return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> +}
> +
> +int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
> +					   int instance_id,
> +					   enum hp_wmi_data_type type)
> +{
> +	char *str_value = NULL;
> +	int value_len;
> +	int status = 0;
> +	u32 size = 0;
> +	u32 int_value;
> +	int elem = 0;
> +	int reqs;
> +	int eloc;
> +	int pos_values;
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
> +		LANG_CODE_STR,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
> +
> +	for (elem = 1, eloc = 1; elem < hp_wmi_elements_count[type]; elem++, eloc++) {
> +
> +		switch (enum_obj[elem].type) {
> +		case ACPI_TYPE_STRING:
> +
> +			if (PREREQUISITES != elem && ENUM_POSSIBLE_VALUES != elem) {
> +				status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
> +							       enum_obj[elem].string.length,
> +							       &str_value, &value_len);
> +				if (ACPI_FAILURE(status))
> +					continue;
> +
> +			}
> +			break;
> +		case ACPI_TYPE_INTEGER:
> +			int_value = (u32)enum_obj[elem].integer.value;
> +			break;
> +		default:
> +			pr_warn("Unsupported object type [%d]\n", enum_obj[elem].type);
> +			continue;
> +		}
> +
> +		/* stop if extra counter is greater than total number
> +		 * of elements for enumeration type
> +		 */
> +		if (eloc == hp_wmi_elements_count[type])
> +			goto exit_enumeration_package;
> +
> +		/* Assign appropriate element value to corresponding field*/
> +		switch (eloc) {
> +		case VALUE:
> +			break;
> +		case PATH:
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].path, str_value,
> +				sizeof(bioscfg_drv.enumeration_data[instance_id].path));
> +			break;
> +		case IS_READONLY:
> +			bioscfg_drv.enumeration_data[instance_id].is_readonly = int_value;
> +			break;
> +		case DISPLAY_IN_UI:
> +			bioscfg_drv.enumeration_data[instance_id].display_in_ui = int_value;
> +			break;
> +		case REQUIRES_PHYSICAL_PRESENCE:
> +			bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = int_value;
> +			break;
> +		case SEQUENCE:
> +			bioscfg_drv.enumeration_data[instance_id].sequence = int_value;
> +			break;
> +		case PREREQUISITE_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].prerequisitesize = int_value;
> +			if (int_value > 20)
> +				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> +			/*
> +			 * prerequisites element is omitted when
> +			 * prerequisitesSize value is zero.
> +			 */
> +			if (int_value == 0)
> +				eloc++;
> +			break;
> +		case PREREQUISITES:
> +			size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
> +
> +			for (reqs = 0; reqs < size; reqs++) {
> +				status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
> +							       enum_obj[elem].string.length,
> +							       &str_value, &value_len);
> +				if (ACPI_FAILURE(status))
> +					break;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
> +					str_value,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +				if (reqs != (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +
> +				kfree(str_value);
> +				str_value = NULL;
> +			}
> +			break;
> +
> +		case SECURITY_LEVEL:
> +			bioscfg_drv.enumeration_data[instance_id].security_level = int_value;
> +			break;
> +
> +		case ENUM_CURRENT_VALUE:
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> +				str_value, sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> +			break;
> +		case ENUM_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].size = int_value;
> +			break;
> +		case ENUM_POSSIBLE_VALUES:
> +			size = bioscfg_drv.enumeration_data[instance_id].size;
> +			for (pos_values = 0; pos_values < size; pos_values++) {
> +				status = convert_hexstr_to_str(&enum_obj[elem + pos_values].string.pointer,
> +							       enum_obj[elem  + pos_values].string.length,
> +							       &str_value, &value_len);
> +				if (ACPI_FAILURE(status))
> +					break;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
> +					str_value,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				if (pos_values < (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				kfree(str_value);
> +				str_value = NULL;
> +			}
> +			break;
> +		default:
> +			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> +			break;
> +		}
> +
> +		kfree(str_value);
> +		str_value = NULL;
> +	}
> +
> +exit_enumeration_package:
> +		kfree(str_value);
> +		str_value = NULL;
> +	return 0;
> +}
> +
> +/*
> + * populate_enumeration_buffer_data() -
> + * Populate all properties of an instance under enumeration attribute
> + *
> + * @enum_obj: ACPI object with enumeration data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + * @enumeration_property_count: Total properties count under enumeration type
> + */
> +int populate_enumeration_buffer_data(union acpi_object *enum_obj, int instance_id,

Please replace:

union acpi_object *enum_obj

with:

u16 *buffer_ptr, size_t buffer_size,

for better readability, but also because actually walking obj->buffer.pointer
feels wrong. What if some other code later wants to also check the buffer,
but now obj->buffer.pointer is all of a sudden pointing to the end ?

Also you should pass in the (remaining) size and also pass this into
get_string_from_buffer() and into get_integer_from_buffer() and have
them check that they do not run pass the end of the buffer.

Also please adjust hp_init_bios_attributes() for it to have local:

u16 *buffer_ptr;
size_t buffer_size;

variables and for it to pass them into it's get_string_from_buffer()
call before it passes them to populate_enumeration_buffer_data()

These changes have 2 goals:

1. don't modify the contents of the acpi_object. In general for
 things like walking pointers you should use a local variable
 not change the members of a passed-by-reference struct, to
 avoid surprising the caller

2. add bounds check everywhere to ensure that you don't run
 past the end of the buffer while parsing it.


> +			      struct kobject *attr_name_kobj)
> +{
> +
> +	bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
> +	bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
> +		attr_name_kobj->name,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
> +		attr_name_kobj->name,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +
> +	/* Populate enumeration elements */
> +	populate_enumeration_elements_from_buffer(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
> +	update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
> +				    &enumeration_current_val);
> +	friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
> +				  attr_name_kobj->name,
> +				   bioscfg_drv.enumeration_data[instance_id].display_name,
> +				   sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +
> +	return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> +}
> +
> +int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
> +					      int instance_id,
> +					      enum hp_wmi_data_type type)
> +{
> +	int status;
> +	char *str = NULL;
> +	int elem;
> +	int reqs;
> +	int integer;
> +	int size = 0;
> +	int values;
> +
> +	elem = 0;
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
> +		LANG_CODE_STR,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
> +
> +	for (elem = 1; elem < 3; elem++) {
> +
> +		status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +		if (ACPI_FAILURE(status))
> +			continue;
> +
> +		switch (elem) {
> +		case VALUE:
> +			/* Skip 'Value' since 'CurrentValue' is reported. */
> +			break;
> +		case PATH:
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].path,
> +				str, sizeof(bioscfg_drv.enumeration_data[instance_id].path));
> +			break;
> +		default:
> +			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> +			break;
> +		}
> +		kfree(str);
> +		str = NULL;
> +	}
> +
> +	for (elem = 3; elem < hp_wmi_elements_count[type]; elem++) {
> +		if (PREREQUISITES != elem && ENUM_CURRENT_VALUE != elem && ENUM_POSSIBLE_VALUES != elem)
> +			status = get_integer_from_buffer((int **)&enum_obj->buffer.pointer, (int *)&integer);
> +
> +		if (ACPI_FAILURE(status))
> +			continue;
> +		switch (elem) {
> +		case IS_READONLY:
> +			bioscfg_drv.enumeration_data[instance_id].is_readonly = integer;
> +			break;
> +		case DISPLAY_IN_UI:
> +			bioscfg_drv.enumeration_data[instance_id].display_in_ui = integer;
> +			break;
> +		case REQUIRES_PHYSICAL_PRESENCE:
> +			bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = integer;
> +			break;
> +		case SEQUENCE:
> +			bioscfg_drv.enumeration_data[instance_id].sequence = integer;
> +			break;
> +		case PREREQUISITE_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].prerequisitesize = integer;
> +			if (integer > 20)
> +				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> +			break;
> +		case PREREQUISITES:
> +			size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
> +			for (reqs = 0; reqs < size; reqs++) {
> +				status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +				if (ACPI_FAILURE(status))
> +					continue;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
> +					str,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +				if (reqs != (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +				kfree(str);
> +				str = NULL;
> +			}
> +			break;
> +		case SECURITY_LEVEL:
> +			bioscfg_drv.enumeration_data[instance_id].security_level = integer;
> +			break;
> +		case ENUM_CURRENT_VALUE:
> +			status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> +				str,
> +				sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> +			break;
> +		case ENUM_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].size = integer;
> +			break;
> +		case ENUM_POSSIBLE_VALUES:
> +			size = bioscfg_drv.enumeration_data[instance_id].size;
> +			for (values = 0; values < size; values++) {
> +				status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +				if (ACPI_FAILURE(status))
> +					continue;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
> +					str,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				if (values != (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				kfree(str);
> +				str = NULL;
> +			}
> +			break;
> +		default:
> +			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> +			break;
> +		}
> +		kfree(str);
> +		str = NULL;
> +	}
> +	kfree(str);
> +	str = NULL;
> +
> +	return 0;
> +}
> +
> +/**
> + * exit_enumeration_attributes() - Clear all attribute data
> + *
> + * Clears all data allocated for this group of attributes
> + */
> +void exit_enumeration_attributes(void)
> +{
> +	int instance_id;
> +
> +	for (instance_id = 0; instance_id < bioscfg_drv.enumeration_instances_count; instance_id++) {
> +		if (bioscfg_drv.enumeration_data[instance_id].attr_name_kobj)
> +			sysfs_remove_group(bioscfg_drv.enumeration_data[instance_id].attr_name_kobj,
> +								&enumeration_attr_group);
> +	}
> +	bioscfg_drv.enumeration_instances_count = 0;
> +
> +	kfree(bioscfg_drv.enumeration_data);
> +	bioscfg_drv.enumeration_data = NULL;
> +}


Regards,

Hans