// SPDX-License-Identifier: GPL-2.0-only
/*
* Common functions for kernel modules using Dell SMBIOS
*
* Copyright (c) Red Hat <[email protected]>
* Copyright (c) 2014 Gabriele Mazzotta <[email protected]>
* Copyright (c) 2014 Pali Rohár <[email protected]>
*
* Based on documentation in the libsmbios package:
* Copyright (C) 2005-2014 Dell Inc.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/container_of.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/capability.h>
#include <linux/dmi.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include "dell-smbios.h"
static u32 da_supported_commands;
static int da_num_tokens;
static struct platform_device *platform_device;
static struct calling_interface_token *da_tokens;
static struct token_sysfs_data *token_entries;
static struct attribute **token_attrs;
static DEFINE_MUTEX(smbios_mutex);
struct token_sysfs_data {
struct device_attribute location_attr;
struct device_attribute value_attr;
struct calling_interface_token *token;
};
struct smbios_device {
struct list_head list;
struct device *device;
int (*call_fn)(struct calling_interface_buffer *arg);
};
struct smbios_call {
u32 need_capability;
int cmd_class;
int cmd_select;
};
/* calls that are whitelisted for given capabilities */
static struct smbios_call call_whitelist[] = {
/* generally tokens are allowed, but may be further filtered or
* restricted by token blacklist or whitelist
*/
{CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_STD},
{CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_AC},
{CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_BAT},
{CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD},
{CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_AC},
{CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_BAT},
/* used by userspace: fwupdate */
{CAP_SYS_ADMIN, CLASS_ADMIN_PROP, SELECT_ADMIN_PROP},
/* used by userspace: fwupd */
{CAP_SYS_ADMIN, CLASS_INFO, SELECT_DOCK},
{CAP_SYS_ADMIN, CLASS_FLASH_INTERFACE, SELECT_FLASH_INTERFACE},
};
/* calls that are explicitly blacklisted */
static struct smbios_call call_blacklist[] = {
{0x0000, 1, 7}, /* manufacturing use */
{0x0000, 6, 5}, /* manufacturing use */
{0x0000, 11, 3}, /* write once */
{0x0000, 11, 7}, /* write once */
{0x0000, 11, 11}, /* write once */
{0x0000, 19, -1}, /* diagnostics */
/* handled by kernel: dell-laptop */
{0x0000, CLASS_INFO, SELECT_RFKILL},
{0x0000, CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT},
{0x0000, CLASS_INFO, SELECT_THERMAL_MANAGEMENT},
};
struct token_range {
u32 need_capability;
u16 min;
u16 max;
};
/* tokens that are whitelisted for given capabilities */
static struct token_range token_whitelist[] = {
/* used by userspace: fwupdate */
{CAP_SYS_ADMIN, CAPSULE_EN_TOKEN, CAPSULE_DIS_TOKEN},
/* can indicate to userspace that WMI is needed */
{0x0000, WSMT_EN_TOKEN, WSMT_DIS_TOKEN}
};
/* tokens that are explicitly blacklisted */
static struct token_range token_blacklist[] = {
{0x0000, 0x0058, 0x0059}, /* ME use */
{0x0000, 0x00CD, 0x00D0}, /* raid shadow copy */
{0x0000, 0x013A, 0x01FF}, /* sata shadow copy */
{0x0000, 0x0175, 0x0176}, /* write once */
{0x0000, 0x0195, 0x0197}, /* diagnostics */
{0x0000, 0x01DC, 0x01DD}, /* manufacturing use */
{0x0000, 0x027D, 0x0284}, /* diagnostics */
{0x0000, 0x02E3, 0x02E3}, /* manufacturing use */
{0x0000, 0x02FF, 0x02FF}, /* manufacturing use */
{0x0000, 0x0300, 0x0302}, /* manufacturing use */
{0x0000, 0x0325, 0x0326}, /* manufacturing use */
{0x0000, 0x0332, 0x0335}, /* fan control */
{0x0000, 0x0350, 0x0350}, /* manufacturing use */
{0x0000, 0x0363, 0x0363}, /* manufacturing use */
{0x0000, 0x0368, 0x0368}, /* manufacturing use */
{0x0000, 0x03F6, 0x03F7}, /* manufacturing use */
{0x0000, 0x049E, 0x049F}, /* manufacturing use */
{0x0000, 0x04A0, 0x04A3}, /* disagnostics */
{0x0000, 0x04E6, 0x04E7}, /* manufacturing use */
{0x0000, 0x4000, 0x7FFF}, /* internal BIOS use */
{0x0000, 0x9000, 0x9001}, /* internal BIOS use */
{0x0000, 0xA000, 0xBFFF}, /* write only */
{0x0000, 0xEFF0, 0xEFFF}, /* internal BIOS use */
/* handled by kernel: dell-laptop */
{0x0000, BRIGHTNESS_TOKEN, BRIGHTNESS_TOKEN},
{0x0000, KBD_LED_OFF_TOKEN, KBD_LED_AUTO_TOKEN},
{0x0000, KBD_LED_AC_TOKEN, KBD_LED_AC_TOKEN},
{0x0000, KBD_LED_AUTO_25_TOKEN, KBD_LED_AUTO_75_TOKEN},
{0x0000, KBD_LED_AUTO_100_TOKEN, KBD_LED_AUTO_100_TOKEN},
{0x0000, GLOBAL_MIC_MUTE_ENABLE, GLOBAL_MIC_MUTE_DISABLE},
};
static LIST_HEAD(smbios_device_list);
int dell_smbios_error(int value)
{
switch (value) {
case 0: /* Completed successfully */
return 0;
case -1: /* Completed with error */
return -EIO;
case -2: /* Function not supported */
return -ENXIO;
default: /* Unknown error */
return -EINVAL;
}
}
EXPORT_SYMBOL_GPL(dell_smbios_error);
int dell_smbios_register_device(struct device *d, void *call_fn)
{
struct smbios_device *priv;
priv = devm_kzalloc(d, sizeof(struct smbios_device), GFP_KERNEL);
if (!priv)
return -ENOMEM;
get_device(d);
priv->device = d;
priv->call_fn = call_fn;
mutex_lock(&smbios_mutex);
list_add_tail(&priv->list, &smbios_device_list);
mutex_unlock(&smbios_mutex);
dev_dbg(d, "Added device: %s\n", d->driver->name);
return 0;
}
EXPORT_SYMBOL_GPL(dell_smbios_register_device);
void dell_smbios_unregister_device(struct device *d)
{
struct smbios_device *priv;
mutex_lock(&smbios_mutex);
list_for_each_entry(priv, &smbios_device_list, list) {
if (priv->device == d) {
list_del(&priv->list);
put_device(d);
break;
}
}
mutex_unlock(&smbios_mutex);
dev_dbg(d, "Remove device: %s\n", d->driver->name);
}
EXPORT_SYMBOL_GPL(dell_smbios_unregister_device);
int dell_smbios_call_filter(struct device *d,
struct calling_interface_buffer *buffer)
{
u16 t = 0;
int i;
/* can't make calls over 30 */
if (buffer->cmd_class > 30) {
dev_dbg(d, "class too big: %u\n", buffer->cmd_class);
return -EINVAL;
}
/* supported calls on the particular system */
if (!(da_supported_commands & (1 << buffer->cmd_class))) {
dev_dbg(d, "invalid command, supported commands: 0x%8x\n",
da_supported_commands);
return -EINVAL;
}
/* match against call blacklist */
for (i = 0; i < ARRAY_SIZE(call_blacklist); i++) {
if (buffer->cmd_class != call_blacklist[i].cmd_class)
continue;
if (buffer->cmd_select != call_blacklist[i].cmd_select &&
call_blacklist[i].cmd_select != -1)
continue;
dev_dbg(d, "blacklisted command: %u/%u\n",
buffer->cmd_class, buffer->cmd_select);
return -EINVAL;
}
/* if a token call, find token ID */
if ((buffer->cmd_class == CLASS_TOKEN_READ ||
buffer->cmd_class == CLASS_TOKEN_WRITE) &&
buffer->cmd_select < 3) {
/* tokens enabled ? */
if (!da_tokens) {
dev_dbg(d, "no token support on this system\n");
return -EINVAL;
}
/* find the matching token ID */
for (i = 0; i < da_num_tokens; i++) {
if (da_tokens[i].location != buffer->input[0])
continue;
t = da_tokens[i].tokenID;
break;
}
/* token call; but token didn't exist */
if (!t) {
dev_dbg(d, "token at location %04x doesn't exist\n",
buffer->input[0]);
return -EINVAL;
}
/* match against token blacklist */
for (i = 0; i < ARRAY_SIZE(token_blacklist); i++) {
if (!token_blacklist[i].min || !token_blacklist[i].max)
continue;
if (t >= token_blacklist[i].min &&
t <= token_blacklist[i].max)
return -EINVAL;
}
/* match against token whitelist */
for (i = 0; i < ARRAY_SIZE(token_whitelist); i++) {
if (!token_whitelist[i].min || !token_whitelist[i].max)
continue;
if (t < token_whitelist[i].min ||
t > token_whitelist[i].max)
continue;
if (!token_whitelist[i].need_capability ||
capable(token_whitelist[i].need_capability)) {
dev_dbg(d, "whitelisted token: %x\n", t);
return 0;
}
}
}
/* match against call whitelist */
for (i = 0; i < ARRAY_SIZE(call_whitelist); i++) {
if (buffer->cmd_class != call_whitelist[i].cmd_class)
continue;
if (buffer->cmd_select != call_whitelist[i].cmd_select)
continue;
if (!call_whitelist[i].need_capability ||
capable(call_whitelist[i].need_capability)) {
dev_dbg(d, "whitelisted capable command: %u/%u\n",
buffer->cmd_class, buffer->cmd_select);
return 0;
}
dev_dbg(d, "missing capability %d for %u/%u\n",
call_whitelist[i].need_capability,
buffer->cmd_class, buffer->cmd_select);
}
/* not in a whitelist, only allow processes with capabilities */
if (capable(CAP_SYS_RAWIO)) {
dev_dbg(d, "Allowing %u/%u due to CAP_SYS_RAWIO\n",
buffer->cmd_class, buffer->cmd_select);
return 0;
}
return -EACCES;
}
EXPORT_SYMBOL_GPL(dell_smbios_call_filter);
int dell_smbios_call(struct calling_interface_buffer *buffer)
{
int (*call_fn)(struct calling_interface_buffer *) = NULL;
struct device *selected_dev = NULL;
struct smbios_device *priv;
int ret;
mutex_lock(&smbios_mutex);
list_for_each_entry(priv, &smbios_device_list, list) {
if (!selected_dev || priv->device->id >= selected_dev->id) {
dev_dbg(priv->device, "Trying device ID: %d\n",
priv->device->id);
call_fn = priv->call_fn;
selected_dev = priv->device;
}
}
if (!selected_dev) {
ret = -ENODEV;
pr_err("No dell-smbios drivers are loaded\n");
goto out_smbios_call;
}
ret = call_fn(buffer);
out_smbios_call:
mutex_unlock(&smbios_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(dell_smbios_call);
void dell_fill_request(struct calling_interface_buffer *buffer,
u32 arg0, u32 arg1, u32 arg2, u32 arg3)
{
memset(buffer, 0, sizeof(struct calling_interface_buffer));
buffer->input[0] = arg0;
buffer->input[1] = arg1;
buffer->input[2] = arg2;
buffer->input[3] = arg3;
}
EXPORT_SYMBOL_GPL(dell_fill_request);
int dell_send_request(struct calling_interface_buffer *buffer,
u16 class, u16 select)
{
int ret;
buffer->cmd_class = class;
buffer->cmd_select = select;
ret = dell_smbios_call(buffer);
if (ret != 0)
return ret;
return dell_smbios_error(buffer->output[0]);
}
EXPORT_SYMBOL_GPL(dell_send_request);
struct calling_interface_token *dell_smbios_find_token(int tokenid)
{
int i;
if (!da_tokens)
return NULL;
for (i = 0; i < da_num_tokens; i++) {
if (da_tokens[i].tokenID == tokenid)
return &da_tokens[i];
}
return NULL;
}
EXPORT_SYMBOL_GPL(dell_smbios_find_token);
static BLOCKING_NOTIFIER_HEAD(dell_laptop_chain_head);
int dell_laptop_register_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&dell_laptop_chain_head, nb);
}
EXPORT_SYMBOL_GPL(dell_laptop_register_notifier);
int dell_laptop_unregister_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&dell_laptop_chain_head, nb);
}
EXPORT_SYMBOL_GPL(dell_laptop_unregister_notifier);
void dell_laptop_call_notifier(unsigned long action, void *data)
{
blocking_notifier_call_chain(&dell_laptop_chain_head, action, data);
}
EXPORT_SYMBOL_GPL(dell_laptop_call_notifier);
bool dell_smbios_class_is_supported(u16 class)
{
/* Classes over 30 always unsupported */
if (class > 30)
return false;
return da_supported_commands & (1 << class);
}
EXPORT_SYMBOL_GPL(dell_smbios_class_is_supported);
static void __init parse_da_table(const struct dmi_header *dm)
{
/* Final token is a terminator, so we don't want to copy it */
int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
struct calling_interface_token *new_da_tokens;
struct calling_interface_structure *table =
container_of(dm, struct calling_interface_structure, header);
/*
* 4 bytes of table header, plus 7 bytes of Dell header
* plus at least 6 bytes of entry
*/
if (dm->length < 17)
return;
da_supported_commands = table->supportedCmds;
new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
sizeof(struct calling_interface_token),
GFP_KERNEL);
if (!new_da_tokens)
return;
da_tokens = new_da_tokens;
memcpy(da_tokens+da_num_tokens, table->tokens,
sizeof(struct calling_interface_token) * tokens);
da_num_tokens += tokens;
}
static void zero_duplicates(struct device *dev)
{
int i, j;
for (i = 0; i < da_num_tokens; i++) {
if (da_tokens[i].tokenID == 0)
continue;
for (j = i+1; j < da_num_tokens; j++) {
if (da_tokens[j].tokenID == 0)
continue;
if (da_tokens[i].tokenID == da_tokens[j].tokenID) {
dev_dbg(dev, "Zeroing dup token ID %x(%x/%x)\n",
da_tokens[j].tokenID,
da_tokens[j].location,
da_tokens[j].value);
da_tokens[j].tokenID = 0;
}
}
}
}
static void __init find_tokens(const struct dmi_header *dm, void *dummy)
{
switch (dm->type) {
case 0xd4: /* Indexed IO */
case 0xd5: /* Protected Area Type 1 */
case 0xd6: /* Protected Area Type 2 */
break;
case 0xda: /* Calling interface */
parse_da_table(dm);
break;
}
}
static ssize_t location_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, location_attr);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return sysfs_emit(buf, "%08x", data->token->location);
}
static ssize_t value_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, value_attr);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return sysfs_emit(buf, "%08x", data->token->value);
}
static struct attribute_group smbios_attribute_group = {
.name = "tokens"
};
static struct platform_driver platform_driver = {
.driver = {
.name = "dell-smbios",
},
};
static int build_tokens_sysfs(struct platform_device *dev)
{
char *location_name;
char *value_name;
int ret;
int i, j;
token_entries = kcalloc(da_num_tokens, sizeof(*token_entries), GFP_KERNEL);
if (!token_entries)
return -ENOMEM;
/* need to store both location and value + terminator*/
token_attrs = kcalloc((2 * da_num_tokens) + 1, sizeof(*token_attrs), GFP_KERNEL);
if (!token_attrs)
goto out_allocate_attrs;
for (i = 0, j = 0; i < da_num_tokens; i++) {
/* skip empty */
if (da_tokens[i].tokenID == 0)
continue;
token_entries[i].token = &da_tokens[i];
/* add location */
location_name = kasprintf(GFP_KERNEL, "%04x_location",
da_tokens[i].tokenID);
if (location_name == NULL)
goto out_unwind_strings;
sysfs_attr_init(&token_entries[i].location_attr.attr);
token_entries[i].location_attr.attr.name = location_name;
token_entries[i].location_attr.attr.mode = 0444;
token_entries[i].location_attr.show = location_show;
token_attrs[j++] = &token_entries[i].location_attr.attr;
/* add value */
value_name = kasprintf(GFP_KERNEL, "%04x_value",
da_tokens[i].tokenID);
if (!value_name) {
kfree(location_name);
goto out_unwind_strings;
}
sysfs_attr_init(&token_entries[i].value_attr.attr);
token_entries[i].value_attr.attr.name = value_name;
token_entries[i].value_attr.attr.mode = 0444;
token_entries[i].value_attr.show = value_show;
token_attrs[j++] = &token_entries[i].value_attr.attr;
}
smbios_attribute_group.attrs = token_attrs;
ret = sysfs_create_group(&dev->dev.kobj, &smbios_attribute_group);
if (ret)
goto out_unwind_strings;
return 0;
out_unwind_strings:
while (i--) {
kfree(token_entries[i].location_attr.attr.name);
kfree(token_entries[i].value_attr.attr.name);
}
kfree(token_attrs);
out_allocate_attrs:
kfree(token_entries);
return -ENOMEM;
}
static void free_group(struct platform_device *pdev)
{
int i;
sysfs_remove_group(&pdev->dev.kobj,
&smbios_attribute_group);
for (i = 0; i < da_num_tokens; i++) {
kfree(token_entries[i].location_attr.attr.name);
kfree(token_entries[i].value_attr.attr.name);
}
kfree(token_attrs);
kfree(token_entries);
}
static int __init dell_smbios_init(void)
{
int ret, wmi, smm;
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;
}
dmi_walk(find_tokens, NULL);
ret = platform_driver_register(&platform_driver);
if (ret)
goto fail_platform_driver;
platform_device = platform_device_alloc("dell-smbios", 0);
if (!platform_device) {
ret = -ENOMEM;
goto fail_platform_device_alloc;
}
ret = platform_device_add(platform_device);
if (ret)
goto fail_platform_device_add;
/* register backends */
wmi = init_dell_smbios_wmi();
if (wmi)
pr_debug("Failed to initialize WMI backend: %d\n", wmi);
smm = init_dell_smbios_smm();
if (smm)
pr_debug("Failed to initialize SMM backend: %d\n", smm);
if (wmi && smm) {
pr_err("No SMBIOS backends available (wmi: %d, smm: %d)\n",
wmi, smm);
ret = -ENODEV;
goto fail_create_group;
}
if (da_tokens) {
/* duplicate tokens will cause problems building sysfs files */
zero_duplicates(&platform_device->dev);
ret = build_tokens_sysfs(platform_device);
if (ret)
goto fail_sysfs;
}
return 0;
fail_sysfs:
if (!wmi)
exit_dell_smbios_wmi();
if (!smm)
exit_dell_smbios_smm();
fail_create_group:
platform_device_del(platform_device);
fail_platform_device_add:
platform_device_put(platform_device);
fail_platform_device_alloc:
platform_driver_unregister(&platform_driver);
fail_platform_driver:
kfree(da_tokens);
return ret;
}
static void __exit dell_smbios_exit(void)
{
exit_dell_smbios_wmi();
exit_dell_smbios_smm();
mutex_lock(&smbios_mutex);
if (platform_device) {
if (da_tokens)
free_group(platform_device);
platform_device_unregister(platform_device);
platform_driver_unregister(&platform_driver);
}
kfree(da_tokens);
mutex_unlock(&smbios_mutex);
}
module_init(dell_smbios_init);
module_exit(dell_smbios_exit);
MODULE_AUTHOR("Matthew Garrett <[email protected]>");
MODULE_AUTHOR("Gabriele Mazzotta <[email protected]>");
MODULE_AUTHOR("Pali Rohár <[email protected]>");
MODULE_AUTHOR("Mario Limonciello <[email protected]>");
MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
MODULE_LICENSE("GPL");
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