638 lines
16 KiB
C
638 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Common methods for use with dell-wmi-sysman
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*
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* Copyright (c) 2020 Dell Inc.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/fs.h>
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#include <linux/dmi.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/wmi.h>
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#include "dell-wmi-sysman.h"
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#include "../../firmware_attributes_class.h"
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#define MAX_TYPES 4
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#include <linux/nls.h>
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struct wmi_sysman_priv wmi_priv = {
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.mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
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};
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/* reset bios to defaults */
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static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
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static int reset_option = -1;
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static struct class *fw_attr_class;
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/**
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* populate_string_buffer() - populates a string buffer
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* @buffer: the start of the destination buffer
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* @buffer_len: length of the destination buffer
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* @str: the string to insert into buffer
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*/
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ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
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{
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u16 *length = (u16 *)buffer;
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u16 *target = length + 1;
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int ret;
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ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
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target, buffer_len - sizeof(u16));
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if (ret < 0) {
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dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
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return ret;
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}
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if ((ret * sizeof(u16)) > U16_MAX) {
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dev_err(wmi_priv.class_dev, "Error string too long\n");
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return -ERANGE;
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}
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*length = ret * sizeof(u16);
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return sizeof(u16) + *length;
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}
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/**
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* calculate_string_buffer() - determines size of string buffer for use with BIOS communication
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* @str: the string to calculate based upon
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*
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*/
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size_t calculate_string_buffer(const char *str)
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{
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/* u16 length field + one UTF16 char for each input char */
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return sizeof(u16) + strlen(str) * sizeof(u16);
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}
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/**
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* calculate_security_buffer() - determines size of security buffer for authentication scheme
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* @authentication: the authentication content
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*
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* Currently only supported type is Admin password
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*/
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size_t calculate_security_buffer(char *authentication)
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{
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if (strlen(authentication) > 0) {
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return (sizeof(u32) * 2) + strlen(authentication) +
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strlen(authentication) % 2;
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}
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return sizeof(u32) * 2;
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}
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/**
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* populate_security_buffer() - builds a security buffer for authentication scheme
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* @buffer: the buffer to populate
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* @authentication: the authentication content
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*
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* Currently only supported type is PLAIN TEXT
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*/
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void populate_security_buffer(char *buffer, char *authentication)
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{
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char *auth = buffer + sizeof(u32) * 2;
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u32 *sectype = (u32 *) buffer;
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u32 *seclen = sectype + 1;
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*sectype = strlen(authentication) > 0 ? 1 : 0;
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*seclen = strlen(authentication);
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/* plain text */
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if (strlen(authentication) > 0)
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memcpy(auth, authentication, *seclen);
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}
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/**
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* map_wmi_error() - map errors from WMI methods to kernel error codes
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* @error_code: integer error code returned from Dell's firmware
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*/
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int map_wmi_error(int error_code)
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{
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switch (error_code) {
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case 0:
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/* success */
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return 0;
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case 1:
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/* failed */
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return -EIO;
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case 2:
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/* invalid parameter */
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return -EINVAL;
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case 3:
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/* access denied */
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return -EACCES;
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case 4:
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/* not supported */
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return -EOPNOTSUPP;
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case 5:
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/* memory error */
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return -ENOMEM;
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case 6:
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/* protocol error */
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return -EPROTO;
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}
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/* unspecified error */
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return -EIO;
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}
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/**
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* reset_bios_show() - sysfs implementaton for read reset_bios
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* @kobj: Kernel object for this attribute
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* @attr: Kernel object attribute
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* @buf: The buffer to display to userspace
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*/
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static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
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{
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char *start = buf;
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int i;
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for (i = 0; i < MAX_TYPES; i++) {
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if (i == reset_option)
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buf += sprintf(buf, "[%s] ", reset_types[i]);
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else
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buf += sprintf(buf, "%s ", reset_types[i]);
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}
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buf += sprintf(buf, "\n");
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return buf-start;
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}
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/**
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* reset_bios_store() - sysfs implementaton for write reset_bios
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* @kobj: Kernel object for this attribute
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* @attr: Kernel object attribute
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* @buf: The buffer from userspace
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* @count: the size of the buffer from userspace
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*/
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static ssize_t reset_bios_store(struct kobject *kobj,
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struct kobj_attribute *attr, const char *buf, size_t count)
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{
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int type = sysfs_match_string(reset_types, buf);
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int ret;
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if (type < 0)
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return type;
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ret = set_bios_defaults(type);
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pr_debug("reset all attributes request type %d: %d\n", type, ret);
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if (!ret) {
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reset_option = type;
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ret = count;
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}
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return ret;
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}
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/**
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* pending_reboot_show() - sysfs implementaton for read pending_reboot
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* @kobj: Kernel object for this attribute
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* @attr: Kernel object attribute
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* @buf: The buffer to display to userspace
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*
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* Stores default value as 0
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* When current_value is changed this attribute is set to 1 to notify reboot may be required
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*/
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static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%d\n", wmi_priv.pending_changes);
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}
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static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
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static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
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/**
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* create_attributes_level_sysfs_files() - Creates reset_bios and
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* pending_reboot attributes
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*/
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static int create_attributes_level_sysfs_files(void)
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{
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int ret;
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ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
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if (ret)
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return ret;
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ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
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if (ret)
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return ret;
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return 0;
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}
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static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
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char *buf)
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{
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struct kobj_attribute *kattr;
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ssize_t ret = -EIO;
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kattr = container_of(attr, struct kobj_attribute, attr);
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if (kattr->show)
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ret = kattr->show(kobj, kattr, buf);
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return ret;
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}
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static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
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const char *buf, size_t count)
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{
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struct kobj_attribute *kattr;
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ssize_t ret = -EIO;
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kattr = container_of(attr, struct kobj_attribute, attr);
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if (kattr->store)
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ret = kattr->store(kobj, kattr, buf, count);
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return ret;
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}
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static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
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.show = wmi_sysman_attr_show,
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.store = wmi_sysman_attr_store,
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};
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static void attr_name_release(struct kobject *kobj)
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{
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kfree(kobj);
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}
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static struct kobj_type attr_name_ktype = {
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.release = attr_name_release,
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.sysfs_ops = &wmi_sysman_kobj_sysfs_ops,
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};
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/**
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* strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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*/
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void strlcpy_attr(char *dest, char *src)
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{
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size_t len = strlen(src) + 1;
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if (len > 1 && len <= MAX_BUFF)
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strscpy(dest, src, len);
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/*len can be zero because any property not-applicable to attribute can
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* be empty so check only for too long buffers and log error
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*/
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if (len > MAX_BUFF)
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pr_err("Source string returned from BIOS is out of bound!\n");
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}
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/**
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* get_wmiobj_pointer() - Get Content of WMI block for particular instance
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* @instance_id: WMI instance ID
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* @guid_string: WMI GUID (in str form)
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*
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* Fetches the content for WMI block (instance_id) under GUID (guid_string)
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* Caller must kfree the return
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*/
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union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
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{
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struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
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acpi_status status;
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status = wmi_query_block(guid_string, instance_id, &out);
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return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
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}
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/**
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* get_instance_count() - Compute total number of instances under guid_string
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* @guid_string: WMI GUID (in string form)
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*/
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int get_instance_count(const char *guid_string)
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{
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union acpi_object *wmi_obj = NULL;
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int i = 0;
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do {
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kfree(wmi_obj);
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wmi_obj = get_wmiobj_pointer(i, guid_string);
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i++;
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} while (wmi_obj);
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return (i-1);
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}
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/**
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* alloc_attributes_data() - Allocate attributes data for a particular type
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* @attr_type: Attribute type to allocate
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*/
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static int alloc_attributes_data(int attr_type)
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{
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int retval = 0;
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switch (attr_type) {
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case ENUM:
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retval = alloc_enum_data();
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break;
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case INT:
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retval = alloc_int_data();
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break;
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case STR:
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retval = alloc_str_data();
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break;
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case PO:
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retval = alloc_po_data();
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break;
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default:
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break;
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}
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return retval;
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}
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/**
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* destroy_attribute_objs() - Free a kset of kobjects
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* @kset: The kset to destroy
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*
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* Fress kobjects created for each attribute_name under attribute type kset
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*/
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static void destroy_attribute_objs(struct kset *kset)
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{
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struct kobject *pos, *next;
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list_for_each_entry_safe(pos, next, &kset->list, entry) {
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kobject_put(pos);
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}
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}
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/**
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* release_attributes_data() - Clean-up all sysfs directories and files created
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*/
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static void release_attributes_data(void)
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{
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mutex_lock(&wmi_priv.mutex);
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exit_enum_attributes();
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exit_int_attributes();
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exit_str_attributes();
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exit_po_attributes();
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if (wmi_priv.authentication_dir_kset) {
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destroy_attribute_objs(wmi_priv.authentication_dir_kset);
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kset_unregister(wmi_priv.authentication_dir_kset);
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wmi_priv.authentication_dir_kset = NULL;
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}
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if (wmi_priv.main_dir_kset) {
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sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
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sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
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destroy_attribute_objs(wmi_priv.main_dir_kset);
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kset_unregister(wmi_priv.main_dir_kset);
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wmi_priv.main_dir_kset = NULL;
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}
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mutex_unlock(&wmi_priv.mutex);
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}
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/**
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* init_bios_attributes() - Initialize all attributes for a type
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* @attr_type: The attribute type to initialize
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* @guid: The WMI GUID associated with this type to initialize
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*
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* Initialiaze all 4 types of attributes enumeration, integer, string and password object.
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* Populates each attrbute typ's respective properties under sysfs files
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*/
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static int init_bios_attributes(int attr_type, const char *guid)
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{
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struct kobject *attr_name_kobj; //individual attribute names
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union acpi_object *obj = NULL;
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union acpi_object *elements;
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struct kobject *duplicate;
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struct kset *tmp_set;
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int min_elements;
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/* instance_id needs to be reset for each type GUID
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* also, instance IDs are unique within GUID but not across
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*/
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int instance_id = 0;
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int retval = 0;
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retval = alloc_attributes_data(attr_type);
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if (retval)
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return retval;
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switch (attr_type) {
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case ENUM: min_elements = 8; break;
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case INT: min_elements = 9; break;
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case STR: min_elements = 8; break;
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case PO: min_elements = 4; break;
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default:
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pr_err("Error: Unknown attr_type: %d\n", attr_type);
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return -EINVAL;
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}
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/* need to use specific instance_id and guid combination to get right data */
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obj = get_wmiobj_pointer(instance_id, guid);
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if (!obj)
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return -ENODEV;
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mutex_lock(&wmi_priv.mutex);
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while (obj) {
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if (obj->type != ACPI_TYPE_PACKAGE) {
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pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
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retval = -EIO;
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goto err_attr_init;
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}
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if (obj->package.count < min_elements) {
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pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
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obj->package.count, min_elements);
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goto nextobj;
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}
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elements = obj->package.elements;
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/* sanity checking */
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if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
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pr_debug("incorrect element type\n");
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goto nextobj;
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}
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if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
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pr_debug("empty attribute found\n");
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goto nextobj;
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}
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if (attr_type == PO)
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tmp_set = wmi_priv.authentication_dir_kset;
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else
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tmp_set = wmi_priv.main_dir_kset;
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duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
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if (duplicate) {
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pr_debug("Duplicate attribute name found - %s\n",
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elements[ATTR_NAME].string.pointer);
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kobject_put(duplicate);
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goto nextobj;
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}
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/* build attribute */
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attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
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if (!attr_name_kobj) {
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retval = -ENOMEM;
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goto err_attr_init;
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}
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attr_name_kobj->kset = tmp_set;
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retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
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elements[ATTR_NAME].string.pointer);
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if (retval) {
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kobject_put(attr_name_kobj);
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goto err_attr_init;
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}
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/* enumerate all of this attribute */
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switch (attr_type) {
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case ENUM:
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retval = populate_enum_data(elements, instance_id, attr_name_kobj,
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obj->package.count);
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break;
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case INT:
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retval = populate_int_data(elements, instance_id, attr_name_kobj);
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break;
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case STR:
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retval = populate_str_data(elements, instance_id, attr_name_kobj);
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break;
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case PO:
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retval = populate_po_data(elements, instance_id, attr_name_kobj);
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break;
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default:
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break;
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}
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if (retval) {
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pr_debug("failed to populate %s\n",
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elements[ATTR_NAME].string.pointer);
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goto err_attr_init;
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}
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nextobj:
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kfree(obj);
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instance_id++;
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obj = get_wmiobj_pointer(instance_id, guid);
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}
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mutex_unlock(&wmi_priv.mutex);
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return 0;
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err_attr_init:
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mutex_unlock(&wmi_priv.mutex);
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kfree(obj);
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return retval;
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}
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static int __init sysman_init(void)
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{
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int ret = 0;
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if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
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!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
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pr_err("Unable to run on non-Dell system\n");
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return -ENODEV;
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}
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ret = init_bios_attr_set_interface();
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if (ret)
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return ret;
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ret = init_bios_attr_pass_interface();
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if (ret)
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goto err_exit_bios_attr_set_interface;
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|
|
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 <mario.limonciello@outlook.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");
|