diff options
Diffstat (limited to 'drivers/platform/x86/dell-wmi-sysman/sysman.c')
| -rw-r--r-- | drivers/platform/x86/dell-wmi-sysman/sysman.c | 627 |
1 files changed, 627 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell-wmi-sysman/sysman.c new file mode 100644 index 000000000000..dc6dd531c996 --- /dev/null +++ b/drivers/platform/x86/dell-wmi-sysman/sysman.c @@ -0,0 +1,627 @@ +// 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" + +#define MAX_TYPES 4 +#include <linux/nls.h> + +static struct class firmware_attributes_class = { + .name = "firmware-attributes", +}; + +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; + + +/** + * 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 = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); + + if (ret) { + pr_debug("could not create reset_bios file\n"); + return ret; + } + + ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); + if (ret) { + pr_debug("could not create changing_pending_reboot file\n"); + sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); + } + return ret; +} + +static void release_reset_bios_data(void) +{ + sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); + sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); +} + +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 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) + strlcpy(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) +{ + 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; + + 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) +{ + release_reset_bios_data(); + + 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) { + destroy_attribute_objs(wmi_priv.main_dir_kset); + kset_unregister(wmi_priv.main_dir_kset); + } + 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 kset *tmp_set; + + /* 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; + /* need to use specific instance_id and guid combination to get right data */ + obj = get_wmiobj_pointer(instance_id, guid); + if (!obj) + return -ENODEV; + elements = obj->package.elements; + + mutex_lock(&wmi_priv.mutex); + while (elements) { + /* sanity checking */ + 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; + + if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) { + pr_debug("duplicate attribute name found - %s\n", + elements[ATTR_NAME].string.pointer); + 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); + 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); + elements = obj ? obj->package.elements : NULL; + } + + mutex_unlock(&wmi_priv.mutex); + return 0; + +err_attr_init: + mutex_unlock(&wmi_priv.mutex); + release_attributes_data(); + 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 || !wmi_priv.bios_attr_wdev) { + pr_debug("failed to initialize set interface\n"); + goto fail_set_interface; + } + + ret = init_bios_attr_pass_interface(); + if (ret || !wmi_priv.password_attr_wdev) { + pr_debug("failed to initialize pass interface\n"); + goto fail_pass_interface; + } + + ret = class_register(&firmware_attributes_class); + if (ret) + goto fail_class; + + wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0), + NULL, "%s", DRIVER_NAME); + if (IS_ERR(wmi_priv.class_dev)) { + ret = PTR_ERR(wmi_priv.class_dev); + goto fail_classdev; + } + + 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 fail_main_kset; + } + + 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 fail_authentication_kset; + } + + ret = create_attributes_level_sysfs_files(); + if (ret) { + pr_debug("could not create reset BIOS attribute\n"); + goto fail_reset_bios; + } + + ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID); + if (ret) { + pr_debug("failed to populate enumeration type attributes\n"); + goto fail_create_group; + } + + ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID); + if (ret) { + pr_debug("failed to populate integer type attributes\n"); + goto fail_create_group; + } + + ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID); + if (ret) { + pr_debug("failed to populate string type attributes\n"); + goto fail_create_group; + } + + ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID); + if (ret) { + pr_debug("failed to populate pass object type attributes\n"); + goto fail_create_group; + } + + return 0; + +fail_create_group: + release_attributes_data(); + +fail_reset_bios: + if (wmi_priv.authentication_dir_kset) { + kset_unregister(wmi_priv.authentication_dir_kset); + wmi_priv.authentication_dir_kset = NULL; + } + +fail_authentication_kset: + if (wmi_priv.main_dir_kset) { + kset_unregister(wmi_priv.main_dir_kset); + wmi_priv.main_dir_kset = NULL; + } + +fail_main_kset: + device_destroy(&firmware_attributes_class, MKDEV(0, 0)); + +fail_classdev: + class_unregister(&firmware_attributes_class); + +fail_class: + exit_bios_attr_pass_interface(); + +fail_pass_interface: + exit_bios_attr_set_interface(); + +fail_set_interface: + return ret; +} + +static void __exit sysman_exit(void) +{ + release_attributes_data(); + device_destroy(&firmware_attributes_class, MKDEV(0, 0)); + class_unregister(&firmware_attributes_class); + exit_bios_attr_set_interface(); + exit_bios_attr_pass_interface(); +} + +module_init(sysman_init); +module_exit(sysman_exit); + +MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>"); +MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>"); +MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>"); +MODULE_DESCRIPTION("Dell platform setting control interface"); +MODULE_LICENSE("GPL"); |