// 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/fs.h>
#include <linux/dmi.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/wmi.h>
#include "dell-wmi-sysman.h"
#include "../../firmware_attributes_class.h"
#define MAX_TYPES 4
#include <linux/nls.h>
struct wmi_sysman_priv wmi_priv = {
.mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
};
/* reset bios to defaults */
static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
static int reset_option = -1;
static const struct class *fw_attr_class;
/**
* populate_string_buffer() - populates a string buffer
* @buffer: the start of the destination buffer
* @buffer_len: length of the destination buffer
* @str: the string to insert into buffer
*/
ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
{
u16 *length = (u16 *)buffer;
u16 *target = length + 1;
int ret;
ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
target, buffer_len - sizeof(u16));
if (ret < 0) {
dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
return ret;
}
if ((ret * sizeof(u16)) > U16_MAX) {
dev_err(wmi_priv.class_dev, "Error string too long\n");
return -ERANGE;
}
*length = ret * sizeof(u16);
return sizeof(u16) + *length;
}
/**
* calculate_string_buffer() - determines size of string buffer for use with BIOS communication
* @str: the string to calculate based upon
*
*/
size_t calculate_string_buffer(const char *str)
{
/* u16 length field + one UTF16 char for each input char */
return sizeof(u16) + strlen(str) * sizeof(u16);
}
/**
* calculate_security_buffer() - determines size of security buffer for authentication scheme
* @authentication: the authentication content
*
* Currently only supported type is Admin password
*/
size_t calculate_security_buffer(char *authentication)
{
if (strlen(authentication) > 0) {
return (sizeof(u32) * 2) + strlen(authentication) +
strlen(authentication) % 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;
*sectype = strlen(authentication) > 0 ? 1 : 0;
*seclen = strlen(authentication);
/* plain text */
if (strlen(authentication) > 0)
memcpy(auth, authentication, *seclen);
}
/**
* map_wmi_error() - map errors from WMI methods to kernel error codes
* @error_code: integer error code returned from Dell's firmware
*/
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 type = sysfs_match_string(reset_types, buf);
int ret;
if (type < 0)
return type;
ret = set_bios_defaults(type);
pr_debug("reset all attributes request type %d: %d\n", type, ret);
if (!ret) {
reset_option = type;
ret = count;
}
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_attributes_level_sysfs_files() - Creates reset_bios and
* pending_reboot attributes
*/
static int create_attributes_level_sysfs_files(void)
{
int ret;
ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
if (ret)
return ret;
ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
if (ret)
return ret;
return 0;
}
static ssize_t wmi_sysman_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 wmi_sysman_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;
}
static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
.show = wmi_sysman_attr_show,
.store = wmi_sysman_attr_store,
};
static void attr_name_release(struct kobject *kobj)
{
kfree(kobj);
}
static const struct kobj_type attr_name_ktype = {
.release = attr_name_release,
.sysfs_ops = &wmi_sysman_kobj_sysfs_ops,
};
/**
* strlcpy_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 strlcpy_attr(char *dest, char *src)
{
size_t len = strlen(src) + 1;
if (len > 1 && len <= MAX_BUFF)
strscpy(dest, src, len);
/*len can be zero because any property not-applicable to attribute can
* be empty so check only for too long buffers and log error
*/
if (len > MAX_BUFF)
pr_err("Source string returned from BIOS is out of bound!\n");
}
/**
* 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)
{
int ret;
ret = wmi_instance_count(guid_string);
if (ret < 0)
return 0;
return ret;
}
/**
* 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;
list_for_each_entry_safe(pos, next, &kset->list, entry) {
kobject_put(pos);
}
}
/**
* release_attributes_data() - Clean-up all sysfs directories and files created
*/
static void release_attributes_data(void)
{
mutex_lock(&wmi_priv.mutex);
exit_enum_attributes();
exit_int_attributes();
exit_str_attributes();
exit_po_attributes();
if (wmi_priv.authentication_dir_kset) {
destroy_attribute_objs(wmi_priv.authentication_dir_kset);
kset_unregister(wmi_priv.authentication_dir_kset);
wmi_priv.authentication_dir_kset = NULL;
}
if (wmi_priv.main_dir_kset) {
sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
destroy_attribute_objs(wmi_priv.main_dir_kset);
kset_unregister(wmi_priv.main_dir_kset);
wmi_priv.main_dir_kset = NULL;
}
mutex_unlock(&wmi_priv.mutex);
}
/**
* 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;
struct kobject *duplicate;
struct kset *tmp_set;
int min_elements;
/* instance_id needs to be reset for each type GUID
* also, instance IDs are unique within GUID but not across
*/
int instance_id = 0;
int retval = 0;
retval = alloc_attributes_data(attr_type);
if (retval)
return retval;
switch (attr_type) {
case ENUM: min_elements = 8; break;
case INT: min_elements = 9; break;
case STR: min_elements = 8; break;
case PO: min_elements = 4; break;
default:
pr_err("Error: Unknown attr_type: %d\n", attr_type);
return -EINVAL;
}
/* need to use specific instance_id and guid combination to get right data */
obj = get_wmiobj_pointer(instance_id, guid);
if (!obj)
return -ENODEV;
mutex_lock(&wmi_priv.mutex);
while (obj) {
if (obj->type != ACPI_TYPE_PACKAGE) {
pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
retval = -EIO;
goto err_attr_init;
}
if (obj->package.count < min_elements) {
pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
obj->package.count, min_elements);
goto nextobj;
}
elements = obj->package.elements;
/* sanity checking */
if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
pr_debug("incorrect element type\n");
goto nextobj;
}
if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
pr_debug("empty attribute found\n");
goto nextobj;
}
if (attr_type == PO)
tmp_set = wmi_priv.authentication_dir_kset;
else
tmp_set = wmi_priv.main_dir_kset;
duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
if (duplicate) {
pr_debug("Duplicate attribute name found - %s\n",
elements[ATTR_NAME].string.pointer);
kobject_put(duplicate);
goto nextobj;
}
/* build attribute */
attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
if (!attr_name_kobj) {
retval = -ENOMEM;
goto err_attr_init;
}
attr_name_kobj->kset = tmp_set;
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,
obj->package.count);
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) {
pr_debug("failed to populate %s\n",
elements[ATTR_NAME].string.pointer);
goto err_attr_init;
}
nextobj:
kfree(obj);
instance_id++;
obj = get_wmiobj_pointer(instance_id, guid);
}
mutex_unlock(&wmi_priv.mutex);
return 0;
err_attr_init:
mutex_unlock(&wmi_priv.mutex);
kfree(obj);
return retval;
}
static int __init sysman_init(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_bios_attr_set_interface();
if (ret)
return ret;
ret = init_bios_attr_pass_interface();
if (ret)
goto err_exit_bios_attr_set_interface;
if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
pr_debug("failed to find set or pass interface\n");
ret = -ENODEV;
goto err_exit_bios_attr_pass_interface;
}
ret = fw_attributes_class_get(&fw_attr_class);
if (ret)
goto err_exit_bios_attr_pass_interface;
wmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0),
NULL, "%s", DRIVER_NAME);
if (IS_ERR(wmi_priv.class_dev)) {
ret = PTR_ERR(wmi_priv.class_dev);
goto err_unregister_class;
}
wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
&wmi_priv.class_dev->kobj);
if (!wmi_priv.main_dir_kset) {
ret = -ENOMEM;
goto err_destroy_classdev;
}
wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
&wmi_priv.class_dev->kobj);
if (!wmi_priv.authentication_dir_kset) {
ret = -ENOMEM;
goto err_release_attributes_data;
}
ret = create_attributes_level_sysfs_files();
if (ret) {
pr_debug("could not create reset BIOS attribute\n");
goto err_release_attributes_data;
}
ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
if (ret) {
pr_debug("failed to populate enumeration type attributes\n");
goto err_release_attributes_data;
}
ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
if (ret) {
pr_debug("failed to populate integer type attributes\n");
goto err_release_attributes_data;
}
ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
if (ret) {
pr_debug("failed to populate string type attributes\n");
goto err_release_attributes_data;
}
ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
if (ret) {
pr_debug("failed to populate pass object type attributes\n");
goto err_release_attributes_data;
}
return 0;
err_release_attributes_data:
release_attributes_data();
err_destroy_classdev:
device_destroy(fw_attr_class, MKDEV(0, 0));
err_unregister_class:
fw_attributes_class_put();
err_exit_bios_attr_pass_interface:
exit_bios_attr_pass_interface();
err_exit_bios_attr_set_interface:
exit_bios_attr_set_interface();
return ret;
}
static void __exit sysman_exit(void)
{
release_attributes_data();
device_destroy(fw_attr_class, MKDEV(0, 0));
fw_attributes_class_put();
exit_bios_attr_set_interface();
exit_bios_attr_pass_interface();
}
module_init(sysman_init);
module_exit(sysman_exit);
MODULE_AUTHOR("Mario Limonciello <[email protected]>");
MODULE_AUTHOR("Prasanth Ksr <[email protected]>");
MODULE_AUTHOR("Divya Bharathi <[email protected]>");
MODULE_DESCRIPTION("Dell platform setting control interface");
MODULE_LICENSE("GPL");
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