[PATCH] platform/x86: think-lmi: Add WMI interface support on Lenovo platforms

[PATCH] platform/x86: think-lmi: Add WMI interface support on Lenovo platforms

[Mark Pearson]

For Lenovo platforms that support a WMI interface to the BIOS add
support, using the firmware-attributes class, to allow users to access
and modify various BIOS related settings.

Signed-off-by: Mark Pearson <markpearson@lenovo.com>
---
 drivers/platform/x86/Kconfig     |   11 +
 drivers/platform/x86/Makefile    |    1 +
 drivers/platform/x86/think-lmi.c | 1016 ++++++++++++++++++++++++++++++
 include/linux/think-lmi.h        |   72 +++
 4 files changed, 1100 insertions(+)
 create mode 100644 drivers/platform/x86/think-lmi.c
 create mode 100644 include/linux/think-lmi.h

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 461ec6153..c26acc211 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -616,6 +616,17 @@ config THINKPAD_ACPI_HOTKEY_POLL
 	  If you are not sure, say Y here.  The driver enables polling only if
 	  it is strictly necessary to do so.
 
+config THINKPAD_LMI
+	tristate "Lenovo WMI-based systems management driver"
+	default m
+	depends on ACPI_WMI
+	help
+	  This driver allows changing BIOS settings on Lenovo machines whose
+	  BIOS support the WMI interface.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called think-lmi.
+
 config INTEL_ATOMISP2_LED
 	tristate "Intel AtomISP2 camera LED driver"
 	depends on GPIOLIB && LEDS_GPIO
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 60d554073..43afc58c9 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -60,6 +60,7 @@ obj-$(CONFIG_IBM_RTL)		+= ibm_rtl.o
 obj-$(CONFIG_IDEAPAD_LAPTOP)	+= ideapad-laptop.o
 obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
+obj-$(CONFIG_THINKPAD_LMI)	+= think-lmi.o
 
 # Intel
 obj-$(CONFIG_INTEL_ATOMISP2_LED)	+= intel_atomisp2_led.o
diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
new file mode 100644
index 000000000..996f655a2
--- /dev/null
+++ b/drivers/platform/x86/think-lmi.c
@@ -0,0 +1,1016 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * think-lmi.c - Think LMI BIOS configuration driver
+ *
+ * Copyright(C) 2019-2021 Lenovo
+ *
+ *  Original code from Thinkpad-wmi project https://github.com/iksaif/thinkpad-wmi
+ *  Copyright(C) 2017 Corentin Chary <corentin.chary@gmail.com>
+ *  Distributed under the GPL-2.0 license
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/acpi.h>
+#include <linux/fs.h>
+#include <linux/think-lmi.h>
+#include <linux/wmi.h>
+
+/*
+ * Name:
+ *  Lenovo_BiosSetting
+ * Description:
+ *  Get item name and settings for current LMI instance.
+ * Type:
+ *  Query
+ * Returns:
+ *  "Item,Value"
+ * Example:
+ *  "WakeOnLAN,Enable"
+ */
+#define LENOVO_BIOS_SETTING_GUID "51F5230E-9677-46CD-A1CF-C0B23EE34DB7"
+
+/*
+ * Name:
+ *  Lenovo_SetBiosSetting
+ * Description:
+ *  Change the BIOS setting to the desired value using the Lenovo_SetBiosSetting
+ *  class. To save the settings, use the Lenovo_SaveBiosSetting class.
+ *  BIOS settings and values are case sensitive.
+ *  After making changes to the BIOS settings, you must reboot the computer
+ *  before the changes will take effect.
+ * Type:
+ *  Method
+ * Arguments:
+ *  "Item,Value,Password,Encoding,KbdLang;"
+ * Example:
+ *  "WakeOnLAN,Disable,pswd,ascii,us;"
+ */
+#define LENOVO_SET_BIOS_SETTINGS_GUID "98479A64-33F5-4E33-A707-8E251EBBC3A1"
+
+/*
+ * Name:
+ *  Lenovo_SaveBiosSettings
+ * Description:
+ *  Save any pending changes in settings.
+ * Type:
+ *  Method
+ * Arguments:
+ *  "Password,Encoding,KbdLang;"
+ * Example:
+ * "pswd,ascii,us;"
+ */
+#define LENOVO_SAVE_BIOS_SETTINGS_GUID "6A4B54EF-A5ED-4D33-9455-B0D9B48DF4B3"
+
+/*
+ * Name:
+ *  Lenovo_BiosPasswordSettings
+ * Description:
+ *  Return BIOS Password settings
+ * Type:
+ *  Query
+ * Returns:
+ *  PasswordMode, PasswordState, MinLength, MaxLength,
+ *  SupportedEncoding, SupportedKeyboard
+ */
+#define LENOVO_BIOS_PASSWORD_SETTINGS_GUID "8ADB159E-1E32-455C-BC93-308A7ED98246"
+
+/*
+ * Name:
+ *  Lenovo_SetBiosPassword
+ * Description:
+ *  Change a specific password.
+ *  - BIOS settings cannot be changed at the same boot as power-on
+ *    passwords (POP) and hard disk passwords (HDP). If you want to change
+ *    BIOS settings and POP or HDP, you must reboot the system after changing
+ *    one of them.
+ *  - A password cannot be set using this method when one does not already
+ *    exist. Passwords can only be updated or cleared.
+ * Type:
+ *  Method
+ * Arguments:
+ *  "PasswordType,CurrentPassword,NewPassword,Encoding,KbdLang;"
+ * Example:
+ *  "pop,oldpop,newpop,ascii,us;”
+ */
+#define LENOVO_SET_BIOS_PASSWORD_GUID "2651D9FD-911C-4B69-B94E-D0DED5963BD7"
+
+/*
+ * Name:
+ *  Lenovo_GetBiosSelections
+ * Description:
+ *  Return a list of valid settings for a given item.
+ * Type:
+ *  Method
+ * Arguments:
+ *  "Item"
+ * Returns:
+ *  "Value1,Value2,Value3,..."
+ * Example:
+ *  -> "FlashOverLAN"
+ *  <- "Enabled,Disabled"
+ */
+#define LENOVO_GET_BIOS_SELECTIONS_GUID	"7364651A-132F-4FE7-ADAA-40C6C7EE2E3B"
+
+#define TLMI_POP_PWD (1 << 0)
+#define TLMI_PAP_PWD (1 << 1)
+
+/*
+ * Only add an alias on this one, since it's the one used
+ * in tlmi_probe
+ */
+MODULE_ALIAS("tlmi:"LENOVO_BIOS_SETTING_GUID);
+
+static struct class firmware_attributes_class = {
+	.name = "firmware-attributes",
+};
+
+static struct think_lmi tlmi_priv;
+
+/* ------ Utility functions ------------*/
+/* Convert BIOS WMI error string to suitable error code */
+static int tlmi_errstr_to_err(const char *errstr)
+{
+	if (!strcmp(errstr, "Success"))
+		/* Operation completed successfully */
+		return 0;
+	if (!strcmp(errstr, "Not Supported"))
+		/* The feature is not supported on this system */
+		return -EOPNOTSUPP;
+	if (!strcmp(errstr, "Invalid"))
+		/* The item or value provided is not valid parameter */
+		return -EINVAL;
+	if (!strcmp(errstr, "Access Denied"))
+		/*
+		 * The change could not be made due to an authentication problem.
+		 * If a supervisor password exists, the correct supervisor password
+		 * must be provided.
+		 */
+		return -EPERM;
+	if (!strcmp(errstr, "System Busy"))
+		/*
+		 * BIOS changes have already been made that need to be committed.
+		 238G* Reboot the system and try again.
+		 */
+		return -EBUSY;
+
+	pr_debug("Unknown error string: '%s'", errstr);
+	return -EINVAL;
+}
+
+/* Extract error string from WMI return buffer */
+static int tlmi_extract_error(const struct acpi_buffer *output)
+{
+	const union acpi_object *obj;
+	int ret;
+
+	obj = output->pointer;
+	if (!obj || obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
+		return -EIO;
+
+	ret = tlmi_errstr_to_err(obj->string.pointer);
+	kfree(obj);
+	return ret;
+}
+
+/* Utility function to execute WMI call to BIOS */
+static int tlmi_simple_call(const char *guid, const char *arg)
+{
+	const struct acpi_buffer input = { strlen(arg), (char *)arg };
+	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+	acpi_status status;
+
+	/*
+	 * duplicated call required to match bios workaround for behavior
+	 * seen when WMI accessed via scripting on other OS
+	 */
+	status = wmi_evaluate_method(guid, 0, 0, &input, &output);
+	status = wmi_evaluate_method(guid, 0, 0, &input, &output);
+
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	return tlmi_extract_error(&output);
+}
+
+/* Extract output string from WMI return buffer */
+static int tlmi_extract_output_string(const struct acpi_buffer *output,
+					char **string)
+{
+	const union acpi_object *obj;
+
+	obj = output->pointer;
+	if (!obj || obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
+		return -EIO;
+
+	*string = kstrdup(obj->string.pointer, GFP_KERNEL);
+	kfree(obj);
+	return *string ? 0 : -ENOMEM;
+}
+
+/* ------ Core interface functions ------------*/
+
+/* Get password settings from BIOS */
+static int tlmi_get_pwd_settings(struct tlmi_pwdcfg *pwdcfg)
+{
+	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+	const union acpi_object *obj;
+	acpi_status status;
+
+	status = wmi_query_block(LENOVO_BIOS_PASSWORD_SETTINGS_GUID, 0,
+				 &output);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	obj = output.pointer;
+	if (!obj || obj->type != ACPI_TYPE_BUFFER || !obj->buffer.pointer)
+		return -EIO;
+	if (obj->buffer.length != sizeof(struct tlmi_pwdcfg)) {
+
+		/* The size of thinkpad_wmi_pcfg on ThinkStation is larger than ThinkPad.
+		 * To make the driver compatible on different brands, we permit it to get
+		 * the data in below case.
+		 */
+		if (obj->buffer.length > sizeof(struct tlmi_pwdcfg)) {
+			memcpy(pwdcfg, obj->buffer.pointer, sizeof(struct tlmi_pwdcfg));
+			kfree(obj);
+			return 0;
+		}
+		pr_warn("Unknown pwdcfg buffer length %d\n", obj->buffer.length);
+		kfree(obj);
+		return -EIO;
+	}
+
+	memcpy(pwdcfg, obj->buffer.pointer, obj->buffer.length);
+	kfree(obj);
+	return 0;
+}
+
+static int tlmi_set_bios_settings(const char *settings)
+{
+	return tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID,
+				settings);
+}
+
+static int tlmi_save_bios_settings(const char *password)
+{
+	return tlmi_simple_call(LENOVO_SAVE_BIOS_SETTINGS_GUID,
+				password);
+}
+
+static int tlmi_set_bios_password(char *auth_str)
+{
+	return tlmi_simple_call(LENOVO_SET_BIOS_PASSWORD_GUID, auth_str);
+}
+
+static int tlmi_setting(int item, char **value, const char *guid_string)
+{
+	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+	acpi_status status;
+
+	status = wmi_query_block(guid_string, item, &output);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	return tlmi_extract_output_string(&output, value);
+}
+
+static int tlmi_get_bios_selections(const char *item, char **value)
+{
+	const struct acpi_buffer input = { strlen(item), (char *)item };
+	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+	acpi_status status;
+
+	status = wmi_evaluate_method(LENOVO_GET_BIOS_SELECTIONS_GUID,
+				     0, 0, &input, &output);
+
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	return tlmi_extract_output_string(&output, value);
+}
+
+/* ---- Authentication sysfs --------------------------------------------------------- */
+static struct tlmi_pwd_setting *get_pwd_setting(struct kobject *kobj)
+{
+	if (strcmp(kobj->name, "Admin") == 0)
+		return tlmi_priv.pwd_admin;
+	else if (strcmp(kobj->name, "System") == 0)
+		return tlmi_priv.pwd_power;
+	else
+		return NULL;
+}
+
+static ssize_t is_enabled_show(struct kobject *kobj, struct kobj_attribute *attr,
+					  char *buf)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+
+	if (pwd_setting->valid)
+		return sysfs_emit(buf, "1\n");
+	else
+		return sysfs_emit(buf, "0\n");
+}
+
+static struct kobj_attribute auth_is_pass_set = __ATTR_RO(is_enabled);
+
+static ssize_t current_password_store(struct kobject *kobj,
+				      struct kobj_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+	int length;
+
+	if (!pwd_setting)
+		return -EIO;
+
+	length = strlen(buf);
+	if (buf[length-1] == '\n')
+		length--;
+
+	if (length >= TLMI_PWD_MAXLEN)
+		return -EINVAL;
+
+	memcpy(pwd_setting->password, buf, length);
+	pwd_setting->password[length] = '\0';
+	return count;
+}
+
+static struct kobj_attribute auth_current_password = __ATTR_WO(current_password);
+
+static ssize_t new_password_store(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+	char *p, *new_pwd;
+	char pwd_type[4];
+	char *auth_str;
+	int ret = 0, len;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!pwd_setting)
+		return -EIO;
+
+	/* Ensure password, kbdlang and encoding has been set */
+	if (!strlen(pwd_setting->password)) {
+		pr_info("Error: current password not configured\n");
+		return -EINVAL;
+	}
+	if (!strlen(pwd_setting->kbdlang)) {
+		pr_info("Error: kbdlang not configured\n");
+		return -EINVAL;
+	}
+	if (!strlen(pwd_setting->encoding)) {
+		pr_info("Error: Encoding not configured\n");
+		return -EINVAL;
+	}
+
+	new_pwd = kstrdup(buf, GFP_KERNEL);
+	if (!new_pwd)
+		return -ENOMEM;
+	p = memchr(new_pwd, '\n', count);
+
+	if (p != NULL)
+		*p = '\0';
+	if (strlen(new_pwd) > pwd_setting->maxlen) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (strcmp(kobj->name, "Admin") == 0)
+		sprintf(pwd_type, "pap");
+	else
+		sprintf(pwd_type, "pop");
+
+	/* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */
+	len = strlen(pwd_setting->password) + strlen(pwd_setting->encoding)
+		+ strlen(pwd_setting->kbdlang) + 3 /* type */
+		+ strlen(new_pwd) + 6 /* punctuation and terminator*/;
+	auth_str = kzalloc(len, GFP_KERNEL);
+	snprintf(auth_str, len, "%s,%s,%s,%s,%s;",
+		 pwd_type, pwd_setting->password, new_pwd,
+		 pwd_setting->encoding, pwd_setting->kbdlang);
+	ret = tlmi_set_bios_password(auth_str);
+	kfree(auth_str);
+out:
+	kfree(new_pwd);
+	return ret ? ret : count;
+}
+
+static struct kobj_attribute auth_new_password = __ATTR_WO(new_password);
+
+static ssize_t min_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+
+	if (!pwd_setting)
+		return -EIO;
+	return sysfs_emit(buf, "%d\n", pwd_setting->minlen);
+}
+
+static struct kobj_attribute auth_min_pass_length = __ATTR_RO(min_password_length);
+
+static ssize_t max_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+
+	if (!pwd_setting)
+		return -EIO;
+	return sysfs_emit(buf, "%d\n", pwd_setting->maxlen);
+}
+static struct kobj_attribute auth_max_pass_length = __ATTR_RO(max_password_length);
+
+static ssize_t mechanism_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	/* Do we need to add scancode here? */
+	return sysfs_emit(buf, "password\n");
+}
+static struct kobj_attribute auth_mechanism = __ATTR_RO(mechanism);
+
+static ssize_t encoding_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+
+	if (!pwd_setting)
+		return -EIO;
+
+	if (!strlen(pwd_setting->encoding))
+		return sysfs_emit(buf, "Not configured\n");
+
+	return sysfs_emit(buf, "%s\n", pwd_setting->encoding);
+}
+
+static ssize_t encoding_store(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+	int length;
+
+	if (!pwd_setting)
+		return -EIO;
+
+	length = strlen(buf);
+	if (buf[length-1] == '\n')
+		length--;
+	if (length >= TLMI_ENC_MAXLEN)
+		return -EINVAL;
+
+	memcpy(pwd_setting->encoding, buf, length);
+	pwd_setting->encoding[length] = '\0';
+	return count;
+}
+
+static struct kobj_attribute auth_encoding = __ATTR_RW(encoding);
+
+static ssize_t kbdlang_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+
+	if (!pwd_setting)
+		return -EIO;
+
+	if (!strlen(pwd_setting->kbdlang))
+		return sysfs_emit(buf, "Not configured\n");
+
+	return sysfs_emit(buf, "%s\n", pwd_setting->kbdlang);
+}
+
+static ssize_t kbdlang_store(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
+	int length;
+
+	if (!pwd_setting)
+		return -EIO;
+
+	length = strlen(buf);
+	if (buf[length-1] == '\n')
+		length--;
+	if (length >= TLMI_LANG_MAXLEN)
+		return -EINVAL;
+
+	memcpy(pwd_setting->kbdlang, buf, length);
+	pwd_setting->kbdlang[length] = '\0';
+	return count;
+}
+
+static struct kobj_attribute auth_kbdlang = __ATTR_RW(kbdlang);
+
+static ssize_t role_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	if (strcmp(kobj->name, "Admin") == 0)
+		return sprintf(buf, "bios-admin\n");
+	else if (strcmp(kobj->name, "System") == 0)
+		return sprintf(buf, "power-on\n");
+	return -EIO;
+}
+static struct kobj_attribute auth_role = __ATTR_RO(role);
+
+static struct attribute *auth_attrs[] = {
+	&auth_is_pass_set.attr,
+	&auth_min_pass_length.attr,
+	&auth_max_pass_length.attr,
+	&auth_current_password.attr,
+	&auth_new_password.attr,
+	&auth_role.attr,
+	&auth_mechanism.attr,
+	&auth_encoding.attr,
+	&auth_kbdlang.attr,
+	NULL,
+};
+
+static const struct attribute_group auth_attr_group = {
+	.attrs = auth_attrs,
+};
+
+/* ---- Attributes sysfs --------------------------------------------------------- */
+static int get_instance_id(struct kobject *kobj)
+{
+	int i;
+
+	for (i = 0; i <= tlmi_priv.settings_count; i++) {
+		if (tlmi_priv.setting[i]) {
+			if (!(strcmp(kobj->name, tlmi_priv.setting[i]->display_name)))
+				return i;
+		}
+	}
+	return -EIO;
+}
+
+static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	int i = get_instance_id(kobj);
+
+	if (i < 0)
+		return i;
+	if (!tlmi_priv.setting[i])
+		return -EINVAL;
+	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->display_name);
+}
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int i = get_instance_id(kobj);
+	char *item;
+	int ret;
+
+	if (i < 0)
+		return i;
+
+	ret = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
+	if (ret)
+		return ret;
+	ret = sysfs_emit(buf, "%s\n", item);
+	kfree(item);
+	return ret;
+}
+
+static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int i = get_instance_id(kobj);
+
+	if (!tlmi_priv.can_get_bios_selections)
+		return -EOPNOTSUPP;
+	if (i < 0)
+		return i;
+	if (!tlmi_priv.setting[i])
+		return -EINVAL;
+	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->possible_values);
+}
+
+static ssize_t current_value_store(struct kobject *kobj,
+		struct kobj_attribute *attr,
+		const char *buf, size_t count)
+{
+	int i = get_instance_id(kobj);
+	int alloc_len, auth_len = 0;
+	int str_ix = 0;
+	char *auth_str;
+	char *set_str;
+	int ret;
+
+	if (i < 0)
+		return i;
+	if (!tlmi_priv.setting[i])
+		return -EINVAL;
+
+	alloc_len = strlen(tlmi_priv.setting[i]->display_name) + 2 + count;
+
+	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password) {
+		auth_len += strlen(tlmi_priv.pwd_admin->password) + 1
+			+ strlen(tlmi_priv.pwd_admin->encoding) + 1
+			+ strlen(tlmi_priv.pwd_admin->kbdlang) + 1 + 1;
+		auth_str = kmalloc(auth_len, GFP_KERNEL);
+		if (!auth_str)
+			return -ENOMEM;
+
+		sprintf(auth_str, "%s,%s,%s;",
+				tlmi_priv.pwd_admin->password,
+				tlmi_priv.pwd_admin->encoding,
+				tlmi_priv.pwd_admin->kbdlang);
+		alloc_len += 1 + auth_len;
+	}
+
+	set_str = kmalloc(alloc_len, GFP_KERNEL);
+	if (!set_str) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	str_ix += sprintf(set_str, "%s,", tlmi_priv.setting[i]->display_name);
+	str_ix += snprintf(set_str + str_ix, count, "%s", buf);
+	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password)
+		sprintf(set_str + str_ix - 1, ",%s", auth_str);
+	else
+		sprintf(set_str + str_ix - 1, ";");
+
+	ret = tlmi_set_bios_settings(set_str);
+	if (ret)
+		goto err;
+
+	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password)
+		ret = tlmi_save_bios_settings(auth_str);
+	else
+		ret = tlmi_save_bios_settings("");
+	if (ret)
+		goto err;
+
+	kfree(set_str);
+	kfree(auth_str);
+	return count;
+err:
+	kfree(auth_str);
+	kfree(set_str);
+	return ret;
+}
+
+static struct kobj_attribute attr_displ_name =
+		__ATTR_RO(display_name);
+
+static struct kobj_attribute attr_possible_values =
+		__ATTR_RO(possible_values);
+
+static struct kobj_attribute attr_current_val =
+		__ATTR_RW_MODE(current_value, 0600);
+
+static struct attribute *tlmi_attrs[] = {
+	&attr_displ_name.attr,
+	&attr_current_val.attr,
+	&attr_possible_values.attr,
+	NULL,
+};
+
+static const struct attribute_group tlmi_attr_group = {
+	.attrs = tlmi_attrs,
+};
+
+static ssize_t tlmi_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 tlmi_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 tlmi_kobj_sysfs_ops = {
+	.show	= tlmi_attr_show,
+	.store	= tlmi_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	= &tlmi_kobj_sysfs_ops,
+};
+
+/* ---- Initialisation --------------------------------------------------------- */
+static void tlmi_release_attr(void)
+{
+	int i;
+
+	/* Attribute structures */
+	for (i = 0; i < tlmi_priv.settings_count; i++) {
+		if (tlmi_priv.setting[i]) {
+			kfree(tlmi_priv.setting[i]->possible_values);
+
+			if (tlmi_priv.setting[i]->attr_name_kobj)
+				sysfs_remove_group(tlmi_priv.setting[i]->attr_name_kobj,
+						&tlmi_attr_group);
+			kfree(tlmi_priv.setting[i]);
+		}
+	}
+	if (tlmi_priv.attribute_kset) {
+		struct kobject *pos, *next;
+
+		list_for_each_entry_safe(pos, next, &tlmi_priv.attribute_kset->list, entry)
+			kobject_put(pos);
+		kset_unregister(tlmi_priv.attribute_kset);
+	}
+
+	/* Authentication structures */
+	if (tlmi_priv.pwd_admin->attr_name_kobj)
+		sysfs_remove_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
+	kfree(tlmi_priv.pwd_admin);
+	if (tlmi_priv.pwd_power->attr_name_kobj)
+		sysfs_remove_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
+	kfree(tlmi_priv.pwd_power);
+	if (tlmi_priv.authentication_kset) {
+		struct kobject *pos, *next;
+
+		list_for_each_entry_safe(pos, next, &tlmi_priv.authentication_kset->list, entry)
+			kobject_put(pos);
+		kset_unregister(tlmi_priv.authentication_kset);
+	}
+}
+
+static int tlmi_sysfs_init(void)
+{
+	int i, ret;
+
+	ret = class_register(&firmware_attributes_class);
+	if (ret)
+		return ret;
+
+	tlmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
+			NULL, "%s", "thinklmi-sysfs");
+	if (IS_ERR(tlmi_priv.class_dev)) {
+		ret = PTR_ERR(tlmi_priv.class_dev);
+		goto fail_class_created;
+	}
+
+	tlmi_priv.attribute_kset = kset_create_and_add("attributes", NULL,
+			&tlmi_priv.class_dev->kobj);
+	if (!tlmi_priv.attribute_kset) {
+		ret = -ENOMEM;
+		goto fail_device_created;
+	}
+
+	for (i = 0; i < tlmi_priv.settings_count; ++i) {
+		/*Check if index is a valid setting - skip if it isn't */
+		if (!tlmi_priv.setting[i])
+			continue;
+
+		/* build attribute */
+		tlmi_priv.setting[i]->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
+		if (!tlmi_priv.setting[i]->attr_name_kobj) {
+			ret = -ENOMEM;
+			goto fail_create_attr;
+		}
+		tlmi_priv.setting[i]->attr_name_kobj->kset = tlmi_priv.attribute_kset;
+
+		ret = kobject_init_and_add(tlmi_priv.setting[i]->attr_name_kobj, &attr_name_ktype,
+				NULL, "%s", tlmi_priv.setting[i]->display_name);
+		if (ret)
+			goto fail_create_attr;
+
+		ret = sysfs_create_group(tlmi_priv.setting[i]->attr_name_kobj, &tlmi_attr_group);
+		if (ret)
+			goto fail_create_attr;
+	}
+
+	/* Create authentication entries */
+	tlmi_priv.authentication_kset = kset_create_and_add("authentication", NULL,
+								&tlmi_priv.class_dev->kobj);
+	if (!tlmi_priv.authentication_kset) {
+		ret = -ENOMEM;
+		goto fail_create_attr;
+	}
+	tlmi_priv.pwd_admin->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
+	if (!tlmi_priv.pwd_admin->attr_name_kobj) {
+		ret = -ENOMEM;
+		goto fail_create_attr;
+	}
+	tlmi_priv.pwd_admin->attr_name_kobj->kset = tlmi_priv.authentication_kset;
+	ret = kobject_init_and_add(tlmi_priv.pwd_admin->attr_name_kobj, &attr_name_ktype,
+			NULL, "%s", "Admin");
+	if (ret)
+		goto fail_create_attr;
+
+	ret = sysfs_create_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
+	if (ret)
+		goto fail_create_attr;
+
+	tlmi_priv.pwd_power->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
+	if (!tlmi_priv.pwd_power->attr_name_kobj) {
+		ret = -ENOMEM;
+		goto fail_create_attr;
+	}
+	tlmi_priv.pwd_power->attr_name_kobj->kset = tlmi_priv.authentication_kset;
+	ret = kobject_init_and_add(tlmi_priv.pwd_power->attr_name_kobj, &attr_name_ktype,
+			NULL, "%s", "System");
+	if (ret)
+		goto fail_create_attr;
+
+	ret = sysfs_create_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
+	if (ret)
+		goto fail_create_attr;
+
+	return ret;
+
+fail_create_attr:
+	tlmi_release_attr();
+fail_device_created:
+	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
+fail_class_created:
+	class_unregister(&firmware_attributes_class);
+	return ret;
+}
+
+static void tlmi_sysfs_exit(void)
+{
+	tlmi_release_attr();
+	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
+	class_unregister(&firmware_attributes_class);
+}
+
+/* ---- Base Driver -------------------------------------------------------- */
+static int tlmi_analyze(void)
+{
+	struct tlmi_pwdcfg pwdcfg;
+	acpi_status status;
+	int i = 0;
+	int ret;
+
+	if (wmi_has_guid(LENOVO_SET_BIOS_SETTINGS_GUID) &&
+	    wmi_has_guid(LENOVO_SAVE_BIOS_SETTINGS_GUID))
+		tlmi_priv.can_set_bios_settings = true;
+
+	if (wmi_has_guid(LENOVO_GET_BIOS_SELECTIONS_GUID))
+		tlmi_priv.can_get_bios_selections = true;
+
+	if (wmi_has_guid(LENOVO_SET_BIOS_PASSWORD_GUID))
+		tlmi_priv.can_set_bios_password = true;
+
+	if (wmi_has_guid(LENOVO_BIOS_PASSWORD_SETTINGS_GUID))
+		tlmi_priv.can_get_password_settings = true;
+
+	/*
+	 * Try to find the number of valid settings of this machine
+	 * and use it to create sysfs attributes
+	 */
+	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i) {
+		char *item = NULL;
+		int spleng = 0;
+		int num = 0;
+		char *p;
+		struct tlmi_attr_setting *setting;
+
+		tlmi_priv.setting[i] = NULL;
+		status = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
+		if (ACPI_FAILURE(status))
+			break;
+		if (!item)
+			break;
+		if (!*item)
+			continue;
+
+		/* It is not allowed to have '/' for file name. Convert it into '\'. */
+		spleng = strlen(item);
+		for (num = 0; num < spleng; num++) {
+			if (item[num] == '/')
+				item[num] = '\\';
+		}
+
+		/* Remove the value part */
+		p = strchr(item, ',');
+		if (p)
+			*p = '\0';
+
+		/* Create a setting entry */
+		setting = kzalloc(sizeof(struct tlmi_attr_setting), GFP_KERNEL);
+		if (!setting) {
+			ret = -ENOMEM;
+			goto fail_clear_attr;
+		}
+		strscpy(setting->display_name, item, TLMI_SETTINGS_MAXLEN);
+
+		/* If BIOS selections supported, load those */
+		if (tlmi_priv.can_get_bios_selections) {
+			ret = tlmi_get_bios_selections(setting->display_name,
+					&setting->possible_values);
+			if (ret || !setting->possible_values)
+				pr_info("Error retrieving possible values for %d : %s\n",
+						i, setting->display_name);
+		}
+		tlmi_priv.setting[i] = setting;
+		tlmi_priv.settings_count++;
+		kfree(item);
+	}
+
+	/* Create password setting structure */
+	ret = tlmi_get_pwd_settings(&pwdcfg);
+	if (ret)
+		goto fail_clear_attr;
+
+	tlmi_priv.pwd_admin = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
+	if (!tlmi_priv.pwd_admin) {
+		ret = -ENOMEM;
+		goto fail_clear_attr;
+	}
+	sprintf(tlmi_priv.pwd_admin->display_name, "admin");
+	sprintf(tlmi_priv.pwd_admin->kbdlang, "us");
+	sprintf(tlmi_priv.pwd_admin->encoding, "ascii");
+	tlmi_priv.pwd_admin->minlen = pwdcfg.min_length;
+	tlmi_priv.pwd_admin->maxlen = pwdcfg.max_length;
+	if (pwdcfg.password_state & TLMI_PAP_PWD)
+		tlmi_priv.pwd_admin->valid = true;
+
+	tlmi_priv.pwd_power = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
+	if (!tlmi_priv.pwd_power) {
+		ret = -ENOMEM;
+		goto fail_clear_attr;
+	}
+	sprintf(tlmi_priv.pwd_power->display_name, "power-on");
+	sprintf(tlmi_priv.pwd_power->kbdlang, "us");
+	sprintf(tlmi_priv.pwd_power->encoding, "ascii");
+	tlmi_priv.pwd_power->minlen = pwdcfg.min_length;
+	tlmi_priv.pwd_power->maxlen = pwdcfg.max_length;
+
+	if (pwdcfg.password_state & TLMI_POP_PWD)
+		tlmi_priv.pwd_power->valid = true;
+
+	return 0;
+
+fail_clear_attr:
+	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i)
+		kfree(tlmi_priv.setting[i]);
+	return ret;
+}
+
+static int tlmi_remove(struct wmi_device *wdev)
+{
+	tlmi_sysfs_exit();
+	return 0;
+}
+
+static int tlmi_probe(struct wmi_device *wdev, const void *context)
+{
+	tlmi_analyze();
+	return tlmi_sysfs_init();
+}
+
+static const struct wmi_device_id tlmi_id_table[] = {
+	{ .guid_string = LENOVO_BIOS_SETTING_GUID },
+	{ }
+};
+
+static struct wmi_driver tlmi_driver = {
+	.driver = {
+		.name = "think-lmi",
+	},
+	.id_table = tlmi_id_table,
+	.probe = tlmi_probe,
+	.remove = tlmi_remove,
+};
+
+static int __init tlmi_init(void)
+{
+	return wmi_driver_register(&tlmi_driver);
+}
+
+static void __exit tlmi_exit(void)
+{
+	wmi_driver_unregister(&tlmi_driver);
+}
+
+MODULE_AUTHOR("Sugumaran L <slacshiminar@lenovo.com>");
+MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
+MODULE_AUTHOR("Corentin Chary <corentin.chary@gmail.com>");
+MODULE_DESCRIPTION("ThinkLMI Driver");
+MODULE_LICENSE("GPL");
+
+module_init(tlmi_init);
+module_exit(tlmi_exit);
diff --git a/include/linux/think-lmi.h b/include/linux/think-lmi.h
new file mode 100644
index 000000000..9133c0567
--- /dev/null
+++ b/include/linux/think-lmi.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _THINK_LMI_H_
+#define _THINK_LMI_H_
+
+#define TLMI_SETTINGS_COUNT  256
+#define TLMI_SETTINGS_MAXLEN 512
+#define TLMI_PWD_MAXLEN       64
+#define TLMI_PWDTYPE_MAXLEN   64
+#define TLMI_ENC_MAXLEN       64
+#define TLMI_LANG_MAXLEN       4
+/*
+ * Longest string should be in the set command: allow size of BIOS
+ * option and choice
+ */
+#define TLMI_GETSET_MAXLEN (TLMI_SETTINGS_MAXLEN + TLMI_SETTINGS_MAXLEN)
+
+#define THINKLMI_GET_SETTINGS _IOR('T', 1, int *)
+#define THINKLMI_GET_SETTINGS_STRING _IOWR('T', 2, char *)
+#define THINKLMI_SET_SETTING _IOW('T', 3, char *)
+#define THINKLMI_SHOW_SETTING _IOWR('T', 4, char *)
+#define THINKLMI_AUTHENTICATE _IOW('T', 5, char *)
+#define THINKLMI_CHANGE_PASSWORD _IOW('T', 6, char *)
+
+/* password configuration details */
+struct tlmi_pwdcfg {
+	uint32_t password_mode;
+	uint32_t password_state;
+	uint32_t min_length;
+	uint32_t max_length;
+	uint32_t supported_encodings;
+	uint32_t supported_keyboard;
+};
+
+/* password setting details */
+struct tlmi_pwd_setting {
+	struct kobject *attr_name_kobj;
+	bool valid;
+	char display_name[TLMI_PWDTYPE_MAXLEN];
+	char password[TLMI_PWD_MAXLEN];
+	int minlen;
+	int maxlen;
+	char encoding[TLMI_ENC_MAXLEN];
+	char kbdlang[TLMI_LANG_MAXLEN];
+};
+
+/* Attribute setting details */
+struct tlmi_attr_setting {
+	struct kobject *attr_name_kobj;
+	char display_name[TLMI_SETTINGS_MAXLEN];
+	char *possible_values;
+};
+
+struct think_lmi {
+	struct wmi_device *wmi_device;
+
+	int settings_count;
+	bool can_set_bios_settings;
+	bool can_get_bios_selections;
+	bool can_set_bios_password;
+	bool can_get_password_settings;
+
+	struct tlmi_attr_setting *setting[TLMI_SETTINGS_COUNT];
+	struct device *class_dev;
+	struct kset *attribute_kset;
+	struct kset *authentication_kset;
+	struct tlmi_pwd_setting *pwd_admin;
+	struct tlmi_pwd_setting *pwd_power;
+};
+
+#endif /* !_THINK_LMI_H_ */
+
-- 
2.30.2

Re: [PATCH] platform/x86: think-lmi: Add WMI interface support on Lenovo platforms

[Hans de Goede]

Hi Mark,

On 4/25/21 5:08 PM, Mark Pearson wrote:
> For Lenovo platforms that support a WMI interface to the BIOS add
> support, using the firmware-attributes class, to allow users to access
> and modify various BIOS related settings.
> 
> Signed-off-by: Mark Pearson <markpearson@lenovo.com>

Thank you for this patch, overall it looks good.

Several small review remarks inline / below.

> ---
>  drivers/platform/x86/Kconfig     |   11 +
>  drivers/platform/x86/Makefile    |    1 +
>  drivers/platform/x86/think-lmi.c | 1016 ++++++++++++++++++++++++++++++
>  include/linux/think-lmi.h        |   72 +++
>  4 files changed, 1100 insertions(+)
>  create mode 100644 drivers/platform/x86/think-lmi.c
>  create mode 100644 include/linux/think-lmi.h
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 461ec6153..c26acc211 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -616,6 +616,17 @@ config THINKPAD_ACPI_HOTKEY_POLL
>  	  If you are not sure, say Y here.  The driver enables polling only if
>  	  it is strictly necessary to do so.
>  
> +config THINKPAD_LMI
> +	tristate "Lenovo WMI-based systems management driver"
> +	default m
> +	depends on ACPI_WMI
> +	help
> +	  This driver allows changing BIOS settings on Lenovo machines whose
> +	  BIOS support the WMI interface.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called think-lmi.
> +
>  config INTEL_ATOMISP2_LED
>  	tristate "Intel AtomISP2 camera LED driver"
>  	depends on GPIOLIB && LEDS_GPIO
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 60d554073..43afc58c9 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -60,6 +60,7 @@ obj-$(CONFIG_IBM_RTL)		+= ibm_rtl.o
>  obj-$(CONFIG_IDEAPAD_LAPTOP)	+= ideapad-laptop.o
>  obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
>  obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
> +obj-$(CONFIG_THINKPAD_LMI)	+= think-lmi.o
>  
>  # Intel
>  obj-$(CONFIG_INTEL_ATOMISP2_LED)	+= intel_atomisp2_led.o
> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> new file mode 100644
> index 000000000..996f655a2
> --- /dev/null
> +++ b/drivers/platform/x86/think-lmi.c
> @@ -0,0 +1,1016 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * think-lmi.c - Think LMI BIOS configuration driver
> + *
> + * Copyright(C) 2019-2021 Lenovo
> + *
> + *  Original code from Thinkpad-wmi project https://github.com/iksaif/thinkpad-wmi
> + *  Copyright(C) 2017 Corentin Chary <corentin.chary@gmail.com>
> + *  Distributed under the GPL-2.0 license
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/acpi.h>
> +#include <linux/fs.h>
> +#include <linux/think-lmi.h>
> +#include <linux/wmi.h>
> +
> +/*
> + * Name:
> + *  Lenovo_BiosSetting
> + * Description:
> + *  Get item name and settings for current LMI instance.
> + * Type:
> + *  Query
> + * Returns:
> + *  "Item,Value"
> + * Example:
> + *  "WakeOnLAN,Enable"
> + */
> +#define LENOVO_BIOS_SETTING_GUID "51F5230E-9677-46CD-A1CF-C0B23EE34DB7"
> +
> +/*
> + * Name:
> + *  Lenovo_SetBiosSetting
> + * Description:
> + *  Change the BIOS setting to the desired value using the Lenovo_SetBiosSetting
> + *  class. To save the settings, use the Lenovo_SaveBiosSetting class.
> + *  BIOS settings and values are case sensitive.
> + *  After making changes to the BIOS settings, you must reboot the computer
> + *  before the changes will take effect.
> + * Type:
> + *  Method
> + * Arguments:
> + *  "Item,Value,Password,Encoding,KbdLang;"
> + * Example:
> + *  "WakeOnLAN,Disable,pswd,ascii,us;"
> + */
> +#define LENOVO_SET_BIOS_SETTINGS_GUID "98479A64-33F5-4E33-A707-8E251EBBC3A1"
> +
> +/*
> + * Name:
> + *  Lenovo_SaveBiosSettings
> + * Description:
> + *  Save any pending changes in settings.
> + * Type:
> + *  Method
> + * Arguments:
> + *  "Password,Encoding,KbdLang;"
> + * Example:
> + * "pswd,ascii,us;"
> + */
> +#define LENOVO_SAVE_BIOS_SETTINGS_GUID "6A4B54EF-A5ED-4D33-9455-B0D9B48DF4B3"
> +
> +/*
> + * Name:
> + *  Lenovo_BiosPasswordSettings
> + * Description:
> + *  Return BIOS Password settings
> + * Type:
> + *  Query
> + * Returns:
> + *  PasswordMode, PasswordState, MinLength, MaxLength,
> + *  SupportedEncoding, SupportedKeyboard
> + */
> +#define LENOVO_BIOS_PASSWORD_SETTINGS_GUID "8ADB159E-1E32-455C-BC93-308A7ED98246"
> +
> +/*
> + * Name:
> + *  Lenovo_SetBiosPassword
> + * Description:
> + *  Change a specific password.
> + *  - BIOS settings cannot be changed at the same boot as power-on
> + *    passwords (POP) and hard disk passwords (HDP). If you want to change
> + *    BIOS settings and POP or HDP, you must reboot the system after changing
> + *    one of them.
> + *  - A password cannot be set using this method when one does not already
> + *    exist. Passwords can only be updated or cleared.
> + * Type:
> + *  Method
> + * Arguments:
> + *  "PasswordType,CurrentPassword,NewPassword,Encoding,KbdLang;"
> + * Example:
> + *  "pop,oldpop,newpop,ascii,us;”
> + */
> +#define LENOVO_SET_BIOS_PASSWORD_GUID "2651D9FD-911C-4B69-B94E-D0DED5963BD7"
> +
> +/*
> + * Name:
> + *  Lenovo_GetBiosSelections
> + * Description:
> + *  Return a list of valid settings for a given item.
> + * Type:
> + *  Method
> + * Arguments:
> + *  "Item"
> + * Returns:
> + *  "Value1,Value2,Value3,..."
> + * Example:
> + *  -> "FlashOverLAN"
> + *  <- "Enabled,Disabled"
> + */
> +#define LENOVO_GET_BIOS_SELECTIONS_GUID	"7364651A-132F-4FE7-ADAA-40C6C7EE2E3B"
> +
> +#define TLMI_POP_PWD (1 << 0)
> +#define TLMI_PAP_PWD (1 << 1)
> +
> +/*
> + * Only add an alias on this one, since it's the one used
> + * in tlmi_probe
> + */
> +MODULE_ALIAS("tlmi:"LENOVO_BIOS_SETTING_GUID);

I think that this is leftover code from the older version of the driver ?

> +
> +static struct class firmware_attributes_class = {
> +	.name = "firmware-attributes",
> +};

Ah yes, so this is a problem. The dell-wmi-sysman code
also declares and potentialy registers this same class
(class with the same name).

Although it is pretty much impossible to load both drivers
at the same time, I still think it would be best to add
a small bit of helper code in:

drivers/platform/x86/firmware_attributes_class.c

Which takes care of registering the class and can be a
home for potentially more code sharing in the future.

This helper code can then be enabled with a hidden
tristate Kconfig option which then gets selected in
Kconfig by both the new think-lmi Kconfig option as
well as by the dell-wmi-sysman Kconfig option.

Your next version of this series (well now a series)
should then consist of:

1. A patch adding the drivers/platform/x86/firmware_attributes_class.c code
2. A patch adjusting dell-wmi-sysman.c to use this for its class registration
   (compile tested only is fine)
3. The patch actually adding the think-lmi driver.

Sorry for burdoning you with this, but someone needs
to do this (minor) cleanup before things get messy
with everyone declaring its own version of the
firmware-attributes class.

> +static struct think_lmi tlmi_priv;
> +
> +/* ------ Utility functions ------------*/
> +/* Convert BIOS WMI error string to suitable error code */
> +static int tlmi_errstr_to_err(const char *errstr)
> +{
> +	if (!strcmp(errstr, "Success"))
> +		/* Operation completed successfully */
> +		return 0;
> +	if (!strcmp(errstr, "Not Supported"))
> +		/* The feature is not supported on this system */
> +		return -EOPNOTSUPP;
> +	if (!strcmp(errstr, "Invalid"))
> +		/* The item or value provided is not valid parameter */
> +		return -EINVAL;
> +	if (!strcmp(errstr, "Access Denied"))
> +		/*
> +		 * The change could not be made due to an authentication problem.
> +		 * If a supervisor password exists, the correct supervisor password
> +		 * must be provided.
> +		 */
> +		return -EPERM;
> +	if (!strcmp(errstr, "System Busy"))
> +		/*
> +		 * BIOS changes have already been made that need to be committed.
> +		 238G* Reboot the system and try again.
> +		 */
> +		return -EBUSY;
> +
> +	pr_debug("Unknown error string: '%s'", errstr);
> +	return -EINVAL;
> +}
> +
> +/* Extract error string from WMI return buffer */
> +static int tlmi_extract_error(const struct acpi_buffer *output)
> +{
> +	const union acpi_object *obj;
> +	int ret;
> +
> +	obj = output->pointer;
> +	if (!obj || obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
> +		return -EIO;
> +
> +	ret = tlmi_errstr_to_err(obj->string.pointer);
> +	kfree(obj);

So you kfree the obj here, but what if the earlier checks have
failed and you return -EIO, you could still have a non NULL kobj
there, which presumably should be free-ed then ?

> +	return ret;
> +}
> +
> +/* Utility function to execute WMI call to BIOS */
> +static int tlmi_simple_call(const char *guid, const char *arg)
> +{
> +	const struct acpi_buffer input = { strlen(arg), (char *)arg };
> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_status status;
> +
> +	/*
> +	 * duplicated call required to match bios workaround for behavior
> +	 * seen when WMI accessed via scripting on other OS
> +	 */
> +	status = wmi_evaluate_method(guid, 0, 0, &input, &output);

So what happens to output here ? Maybe free it if necessary
and re-initialize it to { ACPI_ALLOCATE_BUFFER, NULL }; ?

> +	status = wmi_evaluate_method(guid, 0, 0, &input, &output);
> +
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +
> +	return tlmi_extract_error(&output);
> +}
> +
> +/* Extract output string from WMI return buffer */
> +static int tlmi_extract_output_string(const struct acpi_buffer *output,
> +					char **string)
> +{
> +	const union acpi_object *obj;
> +
> +	obj = output->pointer;
> +	if (!obj || obj->type != ACPI_TYPE_STRING || !obj->string.pointer)

Again missing a kfree(obj), as with tlmi_extract_error().

> +		return -EIO;
> +
> +	*string = kstrdup(obj->string.pointer, GFP_KERNEL);
> +	kfree(obj);
> +	return *string ? 0 : -ENOMEM;
> +}
> +
> +/* ------ Core interface functions ------------*/
> +
> +/* Get password settings from BIOS */
> +static int tlmi_get_pwd_settings(struct tlmi_pwdcfg *pwdcfg)
> +{
> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	const union acpi_object *obj;
> +	acpi_status status;
> +
> +	status = wmi_query_block(LENOVO_BIOS_PASSWORD_SETTINGS_GUID, 0,
> +				 &output);
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +
> +	obj = output.pointer;
> +	if (!obj || obj->type != ACPI_TYPE_BUFFER || !obj->buffer.pointer)

Again missing a kfree(obj), as with tlmi_extract_error().

> +		return -EIO;
> +	if (obj->buffer.length != sizeof(struct tlmi_pwdcfg)) {

Replace this with:

	if (obj->buffer.length < sizeof(struct tlmi_pwdcfg)) {

And move the below comment to above the if.

> +
> +		/* The size of thinkpad_wmi_pcfg on ThinkStation is larger than ThinkPad.
> +		 * To make the driver compatible on different brands, we permit it to get
> +		 * the data in below case.
> +		 */

> +		if (obj->buffer.length > sizeof(struct tlmi_pwdcfg)) {
> +			memcpy(pwdcfg, obj->buffer.pointer, sizeof(struct tlmi_pwdcfg));
> +			kfree(obj);
> +			return 0;
> +		}

And remove this if block and ...

> +		pr_warn("Unknown pwdcfg buffer length %d\n", obj->buffer.length);
> +		kfree(obj);
> +		return -EIO;
> +	}
> +
> +	memcpy(pwdcfg, obj->buffer.pointer, obj->buffer.length);

Replace this memcpy with:

	memcpy(pwdcfg, obj->buffer.pointer, sizeof(struct tlmi_pwdcfg));

Would make things a bit cleaner.

> +	kfree(obj);
> +	return 0;
> +}
> +
> +static int tlmi_set_bios_settings(const char *settings)
> +{
> +	return tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID,
> +				settings);
> +}
> +
> +static int tlmi_save_bios_settings(const char *password)
> +{
> +	return tlmi_simple_call(LENOVO_SAVE_BIOS_SETTINGS_GUID,
> +				password);
> +}
> +
> +static int tlmi_set_bios_password(char *auth_str)
> +{
> +	return tlmi_simple_call(LENOVO_SET_BIOS_PASSWORD_GUID, auth_str);
> +}
> +
> +static int tlmi_setting(int item, char **value, const char *guid_string)
> +{
> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_status status;
> +
> +	status = wmi_query_block(guid_string, item, &output);
> +	if (ACPI_FAILURE(status))

Again missing a kfree(obj), as with tlmi_extract_error().

> +		return -EIO;
> +
> +	return tlmi_extract_output_string(&output, value);
> +}
> +
> +static int tlmi_get_bios_selections(const char *item, char **value)
> +{
> +	const struct acpi_buffer input = { strlen(item), (char *)item };
> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_status status;
> +
> +	status = wmi_evaluate_method(LENOVO_GET_BIOS_SELECTIONS_GUID,
> +				     0, 0, &input, &output);
> +
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
> +
> +	return tlmi_extract_output_string(&output, value);
> +}
> +
> +/* ---- Authentication sysfs --------------------------------------------------------- */
> +static struct tlmi_pwd_setting *get_pwd_setting(struct kobject *kobj)
> +{
> +	if (strcmp(kobj->name, "Admin") == 0)
> +		return tlmi_priv.pwd_admin;
> +	else if (strcmp(kobj->name, "System") == 0)
> +		return tlmi_priv.pwd_power;

Below in sysfs_init you create 2 kobject under the authentication
dir, "Admin" and "System". So IMHO you can simplify this function to just:

static struct tlmi_pwd_setting *get_pwd_setting(struct kobject *kobj)
	if (strcmp(kobj->name, "Admin") == 0)
		return tlmi_priv.pwd_admin;
	else
		return tlmi_priv.pwd_power;
}

This has the added advantage of callers not having to check for this
function returning NULL.

IMPORTANT NOTE: during the rest of the review I've come up with another
better solution, see below. So when adjusting this driver, please skip
making this change and go for the better solution below right away.

> +	else
> +		return NULL;
> +}
> +
> +static ssize_t is_enabled_show(struct kobject *kobj, struct kobj_attribute *attr,
> +					  char *buf)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +
> +	if (pwd_setting->valid)
> +		return sysfs_emit(buf, "1\n");
> +	else
> +		return sysfs_emit(buf, "0\n");
> +}
> +
> +static struct kobj_attribute auth_is_pass_set = __ATTR_RO(is_enabled);
> +
> +static ssize_t current_password_store(struct kobject *kobj,
> +				      struct kobj_attribute *attr,
> +				      const char *buf, size_t count)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +	int length;
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change  get_pwd_setting() as suggested above you can drop this check.

> +
> +	length = strlen(buf);
> +	if (buf[length-1] == '\n')
> +		length--;
> +
> +	if (length >= TLMI_PWD_MAXLEN)
> +		return -EINVAL;
> +
> +	memcpy(pwd_setting->password, buf, length);
> +	pwd_setting->password[length] = '\0';
> +	return count;
> +}
> +
> +static struct kobj_attribute auth_current_password = __ATTR_WO(current_password);
> +
> +static ssize_t new_password_store(struct kobject *kobj,
> +				  struct kobj_attribute *attr,
> +				  const char *buf, size_t count)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +	char *p, *new_pwd;
> +	char pwd_type[4];
> +	char *auth_str;
> +	int ret = 0, len;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change get_pwd_setting() as suggested above you can drop this check.

Shouldn't can_set_bios_password be checked here somewhere?

> +
> +	/* Ensure password, kbdlang and encoding has been set */
> +	if (!strlen(pwd_setting->password)) {
> +		pr_info("Error: current password not configured\n");
> +		return -EINVAL;
> +	}
> +	if (!strlen(pwd_setting->kbdlang)) {
> +		pr_info("Error: kbdlang not configured\n");
> +		return -EINVAL;
> +	}

This should probably default to "us" or something like that, so that
the password interface will just work with the basic mandatory
auth attributes from: 
Documentation/ABI/testing/sysfs-class-firmware-attributes

Without an app using this needing to have knowledge of Lenovo
specific attributes.

Oh never-mind, I see that you already specify a default value below,
but then if you also ensure that this can never be cleared in
the encoding_store function, then there is no need for this
len == 0 check here.

Also the Lenovo specific kbdlang and encoding attributes
should be documented in:
Documentation/ABI/testing/sysfs-class-firmware-attributes


> +	if (!strlen(pwd_setting->encoding)) {
> +		pr_info("Error: Encoding not configured\n");
> +		return -EINVAL;
> +	}

IMHO it would be better to set a default encoding value in the driver,
IIRC there is one which is straightforward ascii and one which deals
with raw-scancodes. IMHO it would be good to default to the ascii
one, that will also allow to drop this check.

> +
> +	new_pwd = kstrdup(buf, GFP_KERNEL);
> +	if (!new_pwd)
> +		return -ENOMEM;
> +	p = memchr(new_pwd, '\n', count);

strchr ? You are using strdup, so then using memchr after that
is a bit weird ?

> +
> +	if (p != NULL)
> +		*p = '\0';
> +	if (strlen(new_pwd) > pwd_setting->maxlen) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (strcmp(kobj->name, "Admin") == 0)
> +		sprintf(pwd_type, "pap");
> +	else
> +		sprintf(pwd_type, "pop");

I think it would be cleaner to store the "pap" resp. "pop" strings
inside the tlmi_pwd_setting struct, rather then repeating the strmcp
on the kobj->name already done in get_pwd_setting() here ?

> +
> +	/* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */
> +	len = strlen(pwd_setting->password) + strlen(pwd_setting->encoding)
> +		+ strlen(pwd_setting->kbdlang) + 3 /* type */
> +		+ strlen(new_pwd) + 6 /* punctuation and terminator*/;
> +	auth_str = kzalloc(len, GFP_KERNEL);
> +	snprintf(auth_str, len, "%s,%s,%s,%s,%s;",
> +		 pwd_type, pwd_setting->password, new_pwd,
> +		 pwd_setting->encoding, pwd_setting->kbdlang);
> +	ret = tlmi_set_bios_password(auth_str);
> +	kfree(auth_str);
> +out:
> +	kfree(new_pwd);
> +	return ret ? ret : count;
> +}
> +
> +static struct kobj_attribute auth_new_password = __ATTR_WO(new_password);
> +
> +static ssize_t min_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change get_pwd_setting() as suggested above you can drop this check.

> +	return sysfs_emit(buf, "%d\n", pwd_setting->minlen);
> +}
> +
> +static struct kobj_attribute auth_min_pass_length = __ATTR_RO(min_password_length);
> +
> +static ssize_t max_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change get_pwd_setting() as suggested above you can drop this check.

> +	return sysfs_emit(buf, "%d\n", pwd_setting->maxlen);
> +}
> +static struct kobj_attribute auth_max_pass_length = __ATTR_RO(max_password_length);
> +
> +static ssize_t mechanism_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	/* Do we need to add scancode here? */
> +	return sysfs_emit(buf, "password\n");
> +}
> +static struct kobj_attribute auth_mechanism = __ATTR_RO(mechanism);
> +
> +static ssize_t encoding_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change get_pwd_setting() as suggested above you can drop this check.

> +
> +	if (!strlen(pwd_setting->encoding))
> +		return sysfs_emit(buf, "Not configured\n");

See above, IMHO the driver should start with a default encoding and
it should ensure that it always has a valid encoding (see below).

> +
> +	return sysfs_emit(buf, "%s\n", pwd_setting->encoding);
> +}
> +
> +static ssize_t encoding_store(struct kobject *kobj,
> +				  struct kobj_attribute *attr,
> +				  const char *buf, size_t count)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +	int length;
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change get_pwd_setting() as suggested above you can drop this check.

> +
> +	length = strlen(buf);
> +	if (buf[length-1] == '\n')
> +		length--;
> +	if (length >= TLMI_ENC_MAXLEN)
> +		return -EINVAL;

IIRC there are only a couple of valid encodings, IMHO it would be
better to have an array with valid encodings strings and then use
sysfs_match_string to check if the passed in value is part of the
array with valid encodings strings. This will also take care of
the '\n' mess for you.

You can then also store the index into the array of valid strings
inside pwd_setting->encoding instead of making pwd_setting->encoding
a string.

By storing the index, you can also just make the one which you
want to be the default the first entry in the array of valid
encodings strings, so that index 0 is the default.

> +
> +	memcpy(pwd_setting->encoding, buf, length);
> +	pwd_setting->encoding[length] = '\0';
> +	return count;
> +}
> +
> +static struct kobj_attribute auth_encoding = __ATTR_RW(encoding);
> +
> +static ssize_t kbdlang_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +
> +	if (!pwd_setting)
> +		return -EIO;

If you change get_pwd_setting() as suggested above you can drop this check.

> +
> +	if (!strlen(pwd_setting->kbdlang))
> +		return sysfs_emit(buf, "Not configured\n");

Again, please just set a default from the driver.

> +
> +	return sysfs_emit(buf, "%s\n", pwd_setting->kbdlang);
> +}
> +
> +static ssize_t kbdlang_store(struct kobject *kobj,
> +				  struct kobj_attribute *attr,
> +				  const char *buf, size_t count)
> +{
> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
> +	int length;
> +
> +	if (!pwd_setting)
> +		return -EIO;

Same old, same old.

> +
> +	length = strlen(buf);
> +	if (buf[length-1] == '\n')
> +		length--;
> +	if (length >= TLMI_LANG_MAXLEN)
> +		return -EINVAL;

And disallow setting an empty value here.

> +
> +	memcpy(pwd_setting->kbdlang, buf, length);
> +	pwd_setting->kbdlang[length] = '\0';
> +	return count;
> +}
> +
> +static struct kobj_attribute auth_kbdlang = __ATTR_RW(kbdlang);
> +
> +static ssize_t role_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	if (strcmp(kobj->name, "Admin") == 0)
> +		return sprintf(buf, "bios-admin\n");
> +	else if (strcmp(kobj->name, "System") == 0)
> +		return sprintf(buf, "power-on\n");
> +	return -EIO;

Maybe have a const char * pointer for the role inside struct tlmi_pwd_setting
and use that here ? That would make this function more consistent with
how the other auth related functions work.

> +}
> +static struct kobj_attribute auth_role = __ATTR_RO(role);
> +
> +static struct attribute *auth_attrs[] = {
> +	&auth_is_pass_set.attr,
> +	&auth_min_pass_length.attr,
> +	&auth_max_pass_length.attr,
> +	&auth_current_password.attr,
> +	&auth_new_password.attr,
> +	&auth_role.attr,
> +	&auth_mechanism.attr,
> +	&auth_encoding.attr,
> +	&auth_kbdlang.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group auth_attr_group = {
> +	.attrs = auth_attrs,
> +};
> +
> +/* ---- Attributes sysfs --------------------------------------------------------- */
> +static int get_instance_id(struct kobject *kobj)
> +{
> +	int i;
> +
> +	for (i = 0; i <= tlmi_priv.settings_count; i++) {
> +		if (tlmi_priv.setting[i]) {
> +			if (!(strcmp(kobj->name, tlmi_priv.setting[i]->display_name)))
> +				return i;
> +		}
> +	}
> +	return -EIO;
> +}

I believe you don't need this function, see below.

> +
> +static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *attr,
> +		char *buf)
> +{
> +	int i = get_instance_id(kobj);
> +
> +	if (i < 0)
> +		return i;
> +	if (!tlmi_priv.setting[i])
> +		return -EINVAL;

This whole lookup dance done here is a bit messy and not necessary, you can make
things much simpler by changing:

struct tlmi_attr_setting {
	struct kobject *attr_name_kobj;
	char display_name[TLMI_SETTINGS_MAXLEN];
	char *possible_values;
};

To:

struct tlmi_attr_setting {
	struct kobject kobj;
	char display_name[TLMI_SETTINGS_MAXLEN];
	char *possible_values;
};

Note the kobj now no longer is a pointer, it is an embedded struct. This saves you
from doing (and error checking) a second kzalloc call for this inside ssysfs_init.

And more importantly you can now use container_of to get a pointer to the struct
tlmi_attr_setting belonging to the attribute, like this:

	struct tlmi_attr_setting *setting = container_of(kobj, struct tlmi_attr_setting, kobj);

Making the whole function just:

static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct tlmi_attr_setting *setting = container_of(kobj, struct tlmi_attr_setting, kobj);

	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->display_name);
}

Oh and I just realized you can and should do the same for the auth/password functions to
change the:

	struct kobject *attr_name_kobj;

Inside the struct tlmi_pwd_setting to:

	struct kobject kobj;

And then you can drop the get_pwd_setting() call and replace all it calls with:

	struct tlmi_pwd_setting *pwd_setting = container_of(kobj, struct tlmi_pwd_setting, kobj);

(and drop the NULL pointer checks too).


> +	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->display_name);
> +}
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int i = get_instance_id(kobj);
> +	char *item;
> +	int ret;
> +
> +	if (i < 0)
> +		return i;
> +
> +	ret = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);

Oh you need i here, interesting, I believe in this case it is best to add
an int index field to struct tlmi_attr_setting, initialize that field from
tlmi_analyze() and use that here.

 
> +	if (ret)
> +		return ret;
> +	ret = sysfs_emit(buf, "%s\n", item);
> +	kfree(item);
> +	return ret;
> +}
> +
> +static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int i = get_instance_id(kobj);
> +
> +	if (!tlmi_priv.can_get_bios_selections)
> +		return -EOPNOTSUPP;
> +	if (i < 0)
> +		return i;
> +	if (!tlmi_priv.setting[i])
> +		return -EINVAL;
> +	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->possible_values);
> +}

With the suggested change to use an embedded kobj struct, this function will
also become nice and simple :)

> +
> +static ssize_t current_value_store(struct kobject *kobj,
> +		struct kobj_attribute *attr,
> +		const char *buf, size_t count)
> +{
> +	int i = get_instance_id(kobj);
> +	int alloc_len, auth_len = 0;
> +	int str_ix = 0;
> +	char *auth_str;
> +	char *set_str;
> +	int ret;
> +
> +	if (i < 0)
> +		return i;
> +	if (!tlmi_priv.setting[i])
> +		return -EINVAL;

Shouldn't there be some check on can_set_bios_settings here?


> +
> +	alloc_len = strlen(tlmi_priv.setting[i]->display_name) + 2 + count;

This seems to be off by one, you need 1 extra for the , one extra for
the ; and one extra for the terminating 0.

> +
> +	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password) {
> +		auth_len += strlen(tlmi_priv.pwd_admin->password) + 1
> +			+ strlen(tlmi_priv.pwd_admin->encoding) + 1
> +			+ strlen(tlmi_priv.pwd_admin->kbdlang) + 1 + 1;
> +		auth_str = kmalloc(auth_len, GFP_KERNEL);
> +		if (!auth_str)
> +			return -ENOMEM;
> +
> +		sprintf(auth_str, "%s,%s,%s;",
> +				tlmi_priv.pwd_admin->password,
> +				tlmi_priv.pwd_admin->encoding,
> +				tlmi_priv.pwd_admin->kbdlang);
> +		alloc_len += 1 + auth_len;

I believe you are adding too much to alloc_len here, since
auth_len already contains space for a terminating 0 and so should
alloc_len at this point.

> +	}
> +
> +	set_str = kmalloc(alloc_len, GFP_KERNEL);
> +	if (!set_str) {
> +		ret = -ENOMEM;
> +		goto err;
> +	}
> +
> +	str_ix += sprintf(set_str, "%s,", tlmi_priv.setting[i]->display_name);
> +	str_ix += snprintf(set_str + str_ix, count, "%s", buf);
> +	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password)
> +		sprintf(set_str + str_ix - 1, ",%s", auth_str);
> +	else
> +		sprintf(set_str + str_ix - 1, ";");

The str_ix - 1 here looks like it tries to strip a potential \n
from the passed in buffer, but that if there is no \n there ?

> +
> +	ret = tlmi_set_bios_settings(set_str);
> +	if (ret)
> +		goto err;
> +
> +	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password)
> +		ret = tlmi_save_bios_settings(auth_str);
> +	else
> +		ret = tlmi_save_bios_settings("");
> +	if (ret)
> +		goto err;
> +
> +	kfree(set_str);
> +	kfree(auth_str);
> +	return count;
> +err:
> +	kfree(auth_str);
> +	kfree(set_str);
> +	return ret;
> +}
> +
> +static struct kobj_attribute attr_displ_name =
> +		__ATTR_RO(display_name);
> +
> +static struct kobj_attribute attr_possible_values =
> +		__ATTR_RO(possible_values);
> +
> +static struct kobj_attribute attr_current_val =
> +		__ATTR_RW_MODE(current_value, 0600);
> +
> +static struct attribute *tlmi_attrs[] = {
> +	&attr_displ_name.attr,
> +	&attr_current_val.attr,
> +	&attr_possible_values.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group tlmi_attr_group = {
> +	.attrs = tlmi_attrs,
> +};
> +
> +static ssize_t tlmi_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 tlmi_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 tlmi_kobj_sysfs_ops = {
> +	.show	= tlmi_attr_show,
> +	.store	= tlmi_attr_store,
> +};
> +
> +static void attr_name_release(struct kobject *kobj)
> +{
> +	kfree(kobj);
> +}

If we switch to embedding the kobjects then we no longer need this
function, the memory will be free-ed when we free the encapsultating
structures instead.

> +
> +static struct kobj_type attr_name_ktype = {
> +	.release	= attr_name_release,

And then we can just leave .release NULL here (IOW drop this line).

> +	.sysfs_ops	= &tlmi_kobj_sysfs_ops,
> +};
> +
> +/* ---- Initialisation --------------------------------------------------------- */
> +static void tlmi_release_attr(void)
> +{
> +	int i;
> +
> +	/* Attribute structures */
> +	for (i = 0; i < tlmi_priv.settings_count; i++) {
> +		if (tlmi_priv.setting[i]) {
> +			kfree(tlmi_priv.setting[i]->possible_values);
> +
> +			if (tlmi_priv.setting[i]->attr_name_kobj)
> +				sysfs_remove_group(tlmi_priv.setting[i]->attr_name_kobj,
> +						&tlmi_attr_group);
> +			kfree(tlmi_priv.setting[i]);
> +		}
> +	}
> +	if (tlmi_priv.attribute_kset) {
> +		struct kobject *pos, *next;
> +
> +		list_for_each_entry_safe(pos, next, &tlmi_priv.attribute_kset->list, entry)
> +			kobject_put(pos);
> +		kset_unregister(tlmi_priv.attribute_kset);
> +	}
> +
> +	/* Authentication structures */
> +	if (tlmi_priv.pwd_admin->attr_name_kobj)
> +		sysfs_remove_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
> +	kfree(tlmi_priv.pwd_admin);
> +	if (tlmi_priv.pwd_power->attr_name_kobj)
> +		sysfs_remove_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
> +	kfree(tlmi_priv.pwd_power);
> +	if (tlmi_priv.authentication_kset) {
> +		struct kobject *pos, *next;
> +
> +		list_for_each_entry_safe(pos, next, &tlmi_priv.authentication_kset->list, entry)
> +			kobject_put(pos);
> +		kset_unregister(tlmi_priv.authentication_kset);
> +	}
> +}
> +
> +static int tlmi_sysfs_init(void)
> +{
> +	int i, ret;
> +
> +	ret = class_register(&firmware_attributes_class);
> +	if (ret)
> +		return ret;
> +
> +	tlmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
> +			NULL, "%s", "thinklmi-sysfs");
> +	if (IS_ERR(tlmi_priv.class_dev)) {
> +		ret = PTR_ERR(tlmi_priv.class_dev);
> +		goto fail_class_created;
> +	}
> +
> +	tlmi_priv.attribute_kset = kset_create_and_add("attributes", NULL,
> +			&tlmi_priv.class_dev->kobj);
> +	if (!tlmi_priv.attribute_kset) {
> +		ret = -ENOMEM;
> +		goto fail_device_created;
> +	}
> +
> +	for (i = 0; i < tlmi_priv.settings_count; ++i) {
> +		/*Check if index is a valid setting - skip if it isn't */
> +		if (!tlmi_priv.setting[i])
> +			continue;
> +
> +		/* build attribute */
> +		tlmi_priv.setting[i]->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
> +		if (!tlmi_priv.setting[i]->attr_name_kobj) {
> +			ret = -ENOMEM;
> +			goto fail_create_attr;
> +		}
> +		tlmi_priv.setting[i]->attr_name_kobj->kset = tlmi_priv.attribute_kset;
> +
> +		ret = kobject_init_and_add(tlmi_priv.setting[i]->attr_name_kobj, &attr_name_ktype,
> +				NULL, "%s", tlmi_priv.setting[i]->display_name);
> +		if (ret)
> +			goto fail_create_attr;
> +
> +		ret = sysfs_create_group(tlmi_priv.setting[i]->attr_name_kobj, &tlmi_attr_group);
> +		if (ret)
> +			goto fail_create_attr;
> +	}
> +
> +	/* Create authentication entries */
> +	tlmi_priv.authentication_kset = kset_create_and_add("authentication", NULL,
> +								&tlmi_priv.class_dev->kobj);
> +	if (!tlmi_priv.authentication_kset) {
> +		ret = -ENOMEM;
> +		goto fail_create_attr;
> +	}
> +	tlmi_priv.pwd_admin->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
> +	if (!tlmi_priv.pwd_admin->attr_name_kobj) {
> +		ret = -ENOMEM;
> +		goto fail_create_attr;
> +	}
> +	tlmi_priv.pwd_admin->attr_name_kobj->kset = tlmi_priv.authentication_kset;
> +	ret = kobject_init_and_add(tlmi_priv.pwd_admin->attr_name_kobj, &attr_name_ktype,
> +			NULL, "%s", "Admin");
> +	if (ret)
> +		goto fail_create_attr;
> +
> +	ret = sysfs_create_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
> +	if (ret)
> +		goto fail_create_attr;
> +
> +	tlmi_priv.pwd_power->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
> +	if (!tlmi_priv.pwd_power->attr_name_kobj) {
> +		ret = -ENOMEM;
> +		goto fail_create_attr;
> +	}
> +	tlmi_priv.pwd_power->attr_name_kobj->kset = tlmi_priv.authentication_kset;
> +	ret = kobject_init_and_add(tlmi_priv.pwd_power->attr_name_kobj, &attr_name_ktype,
> +			NULL, "%s", "System");
> +	if (ret)
> +		goto fail_create_attr;
> +
> +	ret = sysfs_create_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
> +	if (ret)
> +		goto fail_create_attr;
> +
> +	return ret;
> +
> +fail_create_attr:
> +	tlmi_release_attr();
> +fail_device_created:
> +	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
> +fail_class_created:
> +	class_unregister(&firmware_attributes_class);
> +	return ret;
> +}
> +
> +static void tlmi_sysfs_exit(void)
> +{
> +	tlmi_release_attr();
> +	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
> +	class_unregister(&firmware_attributes_class);
> +}
> +
> +/* ---- Base Driver -------------------------------------------------------- */
> +static int tlmi_analyze(void)
> +{
> +	struct tlmi_pwdcfg pwdcfg;
> +	acpi_status status;
> +	int i = 0;
> +	int ret;
> +
> +	if (wmi_has_guid(LENOVO_SET_BIOS_SETTINGS_GUID) &&
> +	    wmi_has_guid(LENOVO_SAVE_BIOS_SETTINGS_GUID))
> +		tlmi_priv.can_set_bios_settings = true;
> +
> +	if (wmi_has_guid(LENOVO_GET_BIOS_SELECTIONS_GUID))
> +		tlmi_priv.can_get_bios_selections = true;
> +
> +	if (wmi_has_guid(LENOVO_SET_BIOS_PASSWORD_GUID))
> +		tlmi_priv.can_set_bios_password = true;
> +
> +	if (wmi_has_guid(LENOVO_BIOS_PASSWORD_SETTINGS_GUID))
> +		tlmi_priv.can_get_password_settings = true;
> +
> +	/*
> +	 * Try to find the number of valid settings of this machine
> +	 * and use it to create sysfs attributes
> +	 */
> +	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i) {
> +		char *item = NULL;
> +		int spleng = 0;
> +		int num = 0;
> +		char *p;
> +		struct tlmi_attr_setting *setting;
> +
> +		tlmi_priv.setting[i] = NULL;
> +		status = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
> +		if (ACPI_FAILURE(status))
> +			break;
> +		if (!item)
> +			break;
> +		if (!*item)
> +			continue;
> +
> +		/* It is not allowed to have '/' for file name. Convert it into '\'. */
> +		spleng = strlen(item);
> +		for (num = 0; num < spleng; num++) {
> +			if (item[num] == '/')
> +				item[num] = '\\';
> +		}
> +
> +		/* Remove the value part */
> +		p = strchr(item, ',');
> +		if (p)
> +			*p = '\0';
> +
> +		/* Create a setting entry */
> +		setting = kzalloc(sizeof(struct tlmi_attr_setting), GFP_KERNEL);
> +		if (!setting) {
> +			ret = -ENOMEM;
> +			goto fail_clear_attr;
> +		}
> +		strscpy(setting->display_name, item, TLMI_SETTINGS_MAXLEN);
> +
> +		/* If BIOS selections supported, load those */
> +		if (tlmi_priv.can_get_bios_selections) {
> +			ret = tlmi_get_bios_selections(setting->display_name,
> +					&setting->possible_values);
> +			if (ret || !setting->possible_values)
> +				pr_info("Error retrieving possible values for %d : %s\n",
> +						i, setting->display_name);
> +		}
> +		tlmi_priv.setting[i] = setting;
> +		tlmi_priv.settings_count++;
> +		kfree(item);
> +	}
> +
> +	/* Create password setting structure */
> +	ret = tlmi_get_pwd_settings(&pwdcfg);
> +	if (ret)
> +		goto fail_clear_attr;
> +
> +	tlmi_priv.pwd_admin = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
> +	if (!tlmi_priv.pwd_admin) {
> +		ret = -ENOMEM;
> +		goto fail_clear_attr;
> +	}
> +	sprintf(tlmi_priv.pwd_admin->display_name, "admin");
> +	sprintf(tlmi_priv.pwd_admin->kbdlang, "us");
> +	sprintf(tlmi_priv.pwd_admin->encoding, "ascii");
> +	tlmi_priv.pwd_admin->minlen = pwdcfg.min_length;
> +	tlmi_priv.pwd_admin->maxlen = pwdcfg.max_length;
> +	if (pwdcfg.password_state & TLMI_PAP_PWD)
> +		tlmi_priv.pwd_admin->valid = true;
> +
> +	tlmi_priv.pwd_power = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
> +	if (!tlmi_priv.pwd_power) {
> +		ret = -ENOMEM;
> +		goto fail_clear_attr;
> +	}
> +	sprintf(tlmi_priv.pwd_power->display_name, "power-on");
> +	sprintf(tlmi_priv.pwd_power->kbdlang, "us");
> +	sprintf(tlmi_priv.pwd_power->encoding, "ascii");
> +	tlmi_priv.pwd_power->minlen = pwdcfg.min_length;
> +	tlmi_priv.pwd_power->maxlen = pwdcfg.max_length;
> +
> +	if (pwdcfg.password_state & TLMI_POP_PWD)
> +		tlmi_priv.pwd_power->valid = true;
> +
> +	return 0;
> +
> +fail_clear_attr:
> +	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i)
> +		kfree(tlmi_priv.setting[i]);
> +	return ret;
> +}
> +
> +static int tlmi_remove(struct wmi_device *wdev)
> +{
> +	tlmi_sysfs_exit();
> +	return 0;
> +}
> +
> +static int tlmi_probe(struct wmi_device *wdev, const void *context)
> +{
> +	tlmi_analyze();
> +	return tlmi_sysfs_init();
> +}
> +
> +static const struct wmi_device_id tlmi_id_table[] = {
> +	{ .guid_string = LENOVO_BIOS_SETTING_GUID },
> +	{ }
> +};
> +
> +static struct wmi_driver tlmi_driver = {
> +	.driver = {
> +		.name = "think-lmi",
> +	},
> +	.id_table = tlmi_id_table,
> +	.probe = tlmi_probe,
> +	.remove = tlmi_remove,
> +};
> +
> +static int __init tlmi_init(void)
> +{
> +	return wmi_driver_register(&tlmi_driver);
> +}
> +
> +static void __exit tlmi_exit(void)
> +{
> +	wmi_driver_unregister(&tlmi_driver);
> +}

You can replace the declaration of these functions + the
module_init and module_exit calls below with a single

module_wmi_driver(tlmi_driver);

"call".


> +
> +MODULE_AUTHOR("Sugumaran L <slacshiminar@lenovo.com>");
> +MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
> +MODULE_AUTHOR("Corentin Chary <corentin.chary@gmail.com>");
> +MODULE_DESCRIPTION("ThinkLMI Driver");
> +MODULE_LICENSE("GPL");
> +
> +module_init(tlmi_init);
> +module_exit(tlmi_exit);
> diff --git a/include/linux/think-lmi.h b/include/linux/think-lmi.h
> new file mode 100644
> index 000000000..9133c0567
> --- /dev/null
> +++ b/include/linux/think-lmi.h
> @@ -0,0 +1,72 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#ifndef _THINK_LMI_H_
> +#define _THINK_LMI_H_
> +
> +#define TLMI_SETTINGS_COUNT  256
> +#define TLMI_SETTINGS_MAXLEN 512
> +#define TLMI_PWD_MAXLEN       64
> +#define TLMI_PWDTYPE_MAXLEN   64
> +#define TLMI_ENC_MAXLEN       64
> +#define TLMI_LANG_MAXLEN       4
> +/*
> + * Longest string should be in the set command: allow size of BIOS
> + * option and choice
> + */
> +#define TLMI_GETSET_MAXLEN (TLMI_SETTINGS_MAXLEN + TLMI_SETTINGS_MAXLEN)
> +
> +#define THINKLMI_GET_SETTINGS _IOR('T', 1, int *)
> +#define THINKLMI_GET_SETTINGS_STRING _IOWR('T', 2, char *)
> +#define THINKLMI_SET_SETTING _IOW('T', 3, char *)
> +#define THINKLMI_SHOW_SETTING _IOWR('T', 4, char *)
> +#define THINKLMI_AUTHENTICATE _IOW('T', 5, char *)
> +#define THINKLMI_CHANGE_PASSWORD _IOW('T', 6, char *)

These defines seem to be a left-over from when the think-lmi driver
was providing an ioctl interface, please drop these.

> +
> +/* password configuration details */
> +struct tlmi_pwdcfg {
> +	uint32_t password_mode;
> +	uint32_t password_state;
> +	uint32_t min_length;
> +	uint32_t max_length;
> +	uint32_t supported_encodings;
> +	uint32_t supported_keyboard;
> +};
> +
> +/* password setting details */
> +struct tlmi_pwd_setting {
> +	struct kobject *attr_name_kobj;
> +	bool valid;
> +	char display_name[TLMI_PWDTYPE_MAXLEN];
> +	char password[TLMI_PWD_MAXLEN];
> +	int minlen;
> +	int maxlen;
> +	char encoding[TLMI_ENC_MAXLEN];
> +	char kbdlang[TLMI_LANG_MAXLEN];
> +};
> +
> +/* Attribute setting details */
> +struct tlmi_attr_setting {
> +	struct kobject *attr_name_kobj;
> +	char display_name[TLMI_SETTINGS_MAXLEN];
> +	char *possible_values;
> +};
> +
> +struct think_lmi {
> +	struct wmi_device *wmi_device;
> +
> +	int settings_count;
> +	bool can_set_bios_settings;
> +	bool can_get_bios_selections;
> +	bool can_set_bios_password;
> +	bool can_get_password_settings;
> +
> +	struct tlmi_attr_setting *setting[TLMI_SETTINGS_COUNT];
> +	struct device *class_dev;
> +	struct kset *attribute_kset;
> +	struct kset *authentication_kset;
> +	struct tlmi_pwd_setting *pwd_admin;
> +	struct tlmi_pwd_setting *pwd_power;
> +};
> +
> +#endif /* !_THINK_LMI_H_ */
> +
> 

Regards,

Hans

Re: [PATCH] platform/x86: think-lmi: Add WMI interface support on Lenovo platforms

[Hans de Goede]

Hi,

On 5/6/21 5:44 PM, Hans de Goede wrote:

<snip>

>> +static void attr_name_release(struct kobject *kobj)
>> +{
>> +	kfree(kobj);
>> +}
> 
> If we switch to embedding the kobjects then we no longer need this
> function, the memory will be free-ed when we free the encapsultating
> structures instead.

I just realized that I got this wrong, we still want the release,
but we want the release to free the tlmi_pwd_setting resp. the
tlmi_attr_setting struct embedding the kobj instead
(requiring 2 release functions and 2 separate ktypes).

These kfree-s in the release functions will then replace the kfree-s
done from tlmi_release_attr().

This will ensure that the kobject stays around if userspace has
a file-handle pointing to it when the driver is unbound (this
will delay the calling of release till userspace closes the handle).

Regards,

Hans


>> +
>> +static struct kobj_type attr_name_ktype = {
>> +	.release	= attr_name_release,
> 
> And then we can just leave .release NULL here (IOW drop this line).
> 
>> +	.sysfs_ops	= &tlmi_kobj_sysfs_ops,
>> +};
>> +
>> +/* ---- Initialisation --------------------------------------------------------- */
>> +static void tlmi_release_attr(void)
>> +{
>> +	int i;
>> +
>> +	/* Attribute structures */
>> +	for (i = 0; i < tlmi_priv.settings_count; i++) {
>> +		if (tlmi_priv.setting[i]) {
>> +			kfree(tlmi_priv.setting[i]->possible_values);
>> +
>> +			if (tlmi_priv.setting[i]->attr_name_kobj)
>> +				sysfs_remove_group(tlmi_priv.setting[i]->attr_name_kobj,
>> +						&tlmi_attr_group);
>> +			kfree(tlmi_priv.setting[i]);
>> +		}
>> +	}
>> +	if (tlmi_priv.attribute_kset) {
>> +		struct kobject *pos, *next;
>> +
>> +		list_for_each_entry_safe(pos, next, &tlmi_priv.attribute_kset->list, entry)
>> +			kobject_put(pos);
>> +		kset_unregister(tlmi_priv.attribute_kset);
>> +	}
>> +
>> +	/* Authentication structures */
>> +	if (tlmi_priv.pwd_admin->attr_name_kobj)
>> +		sysfs_remove_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
>> +	kfree(tlmi_priv.pwd_admin);
>> +	if (tlmi_priv.pwd_power->attr_name_kobj)
>> +		sysfs_remove_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
>> +	kfree(tlmi_priv.pwd_power);
>> +	if (tlmi_priv.authentication_kset) {
>> +		struct kobject *pos, *next;
>> +
>> +		list_for_each_entry_safe(pos, next, &tlmi_priv.authentication_kset->list, entry)
>> +			kobject_put(pos);
>> +		kset_unregister(tlmi_priv.authentication_kset);
>> +	}
>> +}
>> +
>> +static int tlmi_sysfs_init(void)
>> +{
>> +	int i, ret;
>> +
>> +	ret = class_register(&firmware_attributes_class);
>> +	if (ret)
>> +		return ret;
>> +
>> +	tlmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
>> +			NULL, "%s", "thinklmi-sysfs");
>> +	if (IS_ERR(tlmi_priv.class_dev)) {
>> +		ret = PTR_ERR(tlmi_priv.class_dev);
>> +		goto fail_class_created;
>> +	}
>> +
>> +	tlmi_priv.attribute_kset = kset_create_and_add("attributes", NULL,
>> +			&tlmi_priv.class_dev->kobj);
>> +	if (!tlmi_priv.attribute_kset) {
>> +		ret = -ENOMEM;
>> +		goto fail_device_created;
>> +	}
>> +
>> +	for (i = 0; i < tlmi_priv.settings_count; ++i) {
>> +		/*Check if index is a valid setting - skip if it isn't */
>> +		if (!tlmi_priv.setting[i])
>> +			continue;
>> +
>> +		/* build attribute */
>> +		tlmi_priv.setting[i]->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
>> +		if (!tlmi_priv.setting[i]->attr_name_kobj) {
>> +			ret = -ENOMEM;
>> +			goto fail_create_attr;
>> +		}
>> +		tlmi_priv.setting[i]->attr_name_kobj->kset = tlmi_priv.attribute_kset;
>> +
>> +		ret = kobject_init_and_add(tlmi_priv.setting[i]->attr_name_kobj, &attr_name_ktype,
>> +				NULL, "%s", tlmi_priv.setting[i]->display_name);
>> +		if (ret)
>> +			goto fail_create_attr;
>> +
>> +		ret = sysfs_create_group(tlmi_priv.setting[i]->attr_name_kobj, &tlmi_attr_group);
>> +		if (ret)
>> +			goto fail_create_attr;
>> +	}
>> +
>> +	/* Create authentication entries */
>> +	tlmi_priv.authentication_kset = kset_create_and_add("authentication", NULL,
>> +								&tlmi_priv.class_dev->kobj);
>> +	if (!tlmi_priv.authentication_kset) {
>> +		ret = -ENOMEM;
>> +		goto fail_create_attr;
>> +	}
>> +	tlmi_priv.pwd_admin->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_admin->attr_name_kobj) {
>> +		ret = -ENOMEM;
>> +		goto fail_create_attr;
>> +	}
>> +	tlmi_priv.pwd_admin->attr_name_kobj->kset = tlmi_priv.authentication_kset;
>> +	ret = kobject_init_and_add(tlmi_priv.pwd_admin->attr_name_kobj, &attr_name_ktype,
>> +			NULL, "%s", "Admin");
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	ret = sysfs_create_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	tlmi_priv.pwd_power->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_power->attr_name_kobj) {
>> +		ret = -ENOMEM;
>> +		goto fail_create_attr;
>> +	}
>> +	tlmi_priv.pwd_power->attr_name_kobj->kset = tlmi_priv.authentication_kset;
>> +	ret = kobject_init_and_add(tlmi_priv.pwd_power->attr_name_kobj, &attr_name_ktype,
>> +			NULL, "%s", "System");
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	ret = sysfs_create_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	return ret;
>> +
>> +fail_create_attr:
>> +	tlmi_release_attr();
>> +fail_device_created:
>> +	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
>> +fail_class_created:
>> +	class_unregister(&firmware_attributes_class);
>> +	return ret;
>> +}
>> +
>> +static void tlmi_sysfs_exit(void)
>> +{
>> +	tlmi_release_attr();
>> +	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
>> +	class_unregister(&firmware_attributes_class);
>> +}
>> +
>> +/* ---- Base Driver -------------------------------------------------------- */
>> +static int tlmi_analyze(void)
>> +{
>> +	struct tlmi_pwdcfg pwdcfg;
>> +	acpi_status status;
>> +	int i = 0;
>> +	int ret;
>> +
>> +	if (wmi_has_guid(LENOVO_SET_BIOS_SETTINGS_GUID) &&
>> +	    wmi_has_guid(LENOVO_SAVE_BIOS_SETTINGS_GUID))
>> +		tlmi_priv.can_set_bios_settings = true;
>> +
>> +	if (wmi_has_guid(LENOVO_GET_BIOS_SELECTIONS_GUID))
>> +		tlmi_priv.can_get_bios_selections = true;
>> +
>> +	if (wmi_has_guid(LENOVO_SET_BIOS_PASSWORD_GUID))
>> +		tlmi_priv.can_set_bios_password = true;
>> +
>> +	if (wmi_has_guid(LENOVO_BIOS_PASSWORD_SETTINGS_GUID))
>> +		tlmi_priv.can_get_password_settings = true;
>> +
>> +	/*
>> +	 * Try to find the number of valid settings of this machine
>> +	 * and use it to create sysfs attributes
>> +	 */
>> +	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i) {
>> +		char *item = NULL;
>> +		int spleng = 0;
>> +		int num = 0;
>> +		char *p;
>> +		struct tlmi_attr_setting *setting;
>> +
>> +		tlmi_priv.setting[i] = NULL;
>> +		status = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
>> +		if (ACPI_FAILURE(status))
>> +			break;
>> +		if (!item)
>> +			break;
>> +		if (!*item)
>> +			continue;
>> +
>> +		/* It is not allowed to have '/' for file name. Convert it into '\'. */
>> +		spleng = strlen(item);
>> +		for (num = 0; num < spleng; num++) {
>> +			if (item[num] == '/')
>> +				item[num] = '\\';
>> +		}
>> +
>> +		/* Remove the value part */
>> +		p = strchr(item, ',');
>> +		if (p)
>> +			*p = '\0';
>> +
>> +		/* Create a setting entry */
>> +		setting = kzalloc(sizeof(struct tlmi_attr_setting), GFP_KERNEL);
>> +		if (!setting) {
>> +			ret = -ENOMEM;
>> +			goto fail_clear_attr;
>> +		}
>> +		strscpy(setting->display_name, item, TLMI_SETTINGS_MAXLEN);
>> +
>> +		/* If BIOS selections supported, load those */
>> +		if (tlmi_priv.can_get_bios_selections) {
>> +			ret = tlmi_get_bios_selections(setting->display_name,
>> +					&setting->possible_values);
>> +			if (ret || !setting->possible_values)
>> +				pr_info("Error retrieving possible values for %d : %s\n",
>> +						i, setting->display_name);
>> +		}
>> +		tlmi_priv.setting[i] = setting;
>> +		tlmi_priv.settings_count++;
>> +		kfree(item);
>> +	}
>> +
>> +	/* Create password setting structure */
>> +	ret = tlmi_get_pwd_settings(&pwdcfg);
>> +	if (ret)
>> +		goto fail_clear_attr;
>> +
>> +	tlmi_priv.pwd_admin = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_admin) {
>> +		ret = -ENOMEM;
>> +		goto fail_clear_attr;
>> +	}
>> +	sprintf(tlmi_priv.pwd_admin->display_name, "admin");
>> +	sprintf(tlmi_priv.pwd_admin->kbdlang, "us");
>> +	sprintf(tlmi_priv.pwd_admin->encoding, "ascii");
>> +	tlmi_priv.pwd_admin->minlen = pwdcfg.min_length;
>> +	tlmi_priv.pwd_admin->maxlen = pwdcfg.max_length;
>> +	if (pwdcfg.password_state & TLMI_PAP_PWD)
>> +		tlmi_priv.pwd_admin->valid = true;
>> +
>> +	tlmi_priv.pwd_power = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_power) {
>> +		ret = -ENOMEM;
>> +		goto fail_clear_attr;
>> +	}
>> +	sprintf(tlmi_priv.pwd_power->display_name, "power-on");
>> +	sprintf(tlmi_priv.pwd_power->kbdlang, "us");
>> +	sprintf(tlmi_priv.pwd_power->encoding, "ascii");
>> +	tlmi_priv.pwd_power->minlen = pwdcfg.min_length;
>> +	tlmi_priv.pwd_power->maxlen = pwdcfg.max_length;
>> +
>> +	if (pwdcfg.password_state & TLMI_POP_PWD)
>> +		tlmi_priv.pwd_power->valid = true;
>> +
>> +	return 0;
>> +
>> +fail_clear_attr:
>> +	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i)
>> +		kfree(tlmi_priv.setting[i]);
>> +	return ret;
>> +}
>> +
>> +static int tlmi_remove(struct wmi_device *wdev)
>> +{
>> +	tlmi_sysfs_exit();
>> +	return 0;
>> +}
>> +
>> +static int tlmi_probe(struct wmi_device *wdev, const void *context)
>> +{
>> +	tlmi_analyze();
>> +	return tlmi_sysfs_init();
>> +}
>> +
>> +static const struct wmi_device_id tlmi_id_table[] = {
>> +	{ .guid_string = LENOVO_BIOS_SETTING_GUID },
>> +	{ }
>> +};
>> +
>> +static struct wmi_driver tlmi_driver = {
>> +	.driver = {
>> +		.name = "think-lmi",
>> +	},
>> +	.id_table = tlmi_id_table,
>> +	.probe = tlmi_probe,
>> +	.remove = tlmi_remove,
>> +};
>> +
>> +static int __init tlmi_init(void)
>> +{
>> +	return wmi_driver_register(&tlmi_driver);
>> +}
>> +
>> +static void __exit tlmi_exit(void)
>> +{
>> +	wmi_driver_unregister(&tlmi_driver);
>> +}
> 
> You can replace the declaration of these functions + the
> module_init and module_exit calls below with a single
> 
> module_wmi_driver(tlmi_driver);
> 
> "call".
> 
> 
>> +
>> +MODULE_AUTHOR("Sugumaran L <slacshiminar@lenovo.com>");
>> +MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
>> +MODULE_AUTHOR("Corentin Chary <corentin.chary@gmail.com>");
>> +MODULE_DESCRIPTION("ThinkLMI Driver");
>> +MODULE_LICENSE("GPL");
>> +
>> +module_init(tlmi_init);
>> +module_exit(tlmi_exit);
>> diff --git a/include/linux/think-lmi.h b/include/linux/think-lmi.h
>> new file mode 100644
>> index 000000000..9133c0567
>> --- /dev/null
>> +++ b/include/linux/think-lmi.h
>> @@ -0,0 +1,72 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +
>> +#ifndef _THINK_LMI_H_
>> +#define _THINK_LMI_H_
>> +
>> +#define TLMI_SETTINGS_COUNT  256
>> +#define TLMI_SETTINGS_MAXLEN 512
>> +#define TLMI_PWD_MAXLEN       64
>> +#define TLMI_PWDTYPE_MAXLEN   64
>> +#define TLMI_ENC_MAXLEN       64
>> +#define TLMI_LANG_MAXLEN       4
>> +/*
>> + * Longest string should be in the set command: allow size of BIOS
>> + * option and choice
>> + */
>> +#define TLMI_GETSET_MAXLEN (TLMI_SETTINGS_MAXLEN + TLMI_SETTINGS_MAXLEN)
>> +
>> +#define THINKLMI_GET_SETTINGS _IOR('T', 1, int *)
>> +#define THINKLMI_GET_SETTINGS_STRING _IOWR('T', 2, char *)
>> +#define THINKLMI_SET_SETTING _IOW('T', 3, char *)
>> +#define THINKLMI_SHOW_SETTING _IOWR('T', 4, char *)
>> +#define THINKLMI_AUTHENTICATE _IOW('T', 5, char *)
>> +#define THINKLMI_CHANGE_PASSWORD _IOW('T', 6, char *)
> 
> These defines seem to be a left-over from when the think-lmi driver
> was providing an ioctl interface, please drop these.
> 
>> +
>> +/* password configuration details */
>> +struct tlmi_pwdcfg {
>> +	uint32_t password_mode;
>> +	uint32_t password_state;
>> +	uint32_t min_length;
>> +	uint32_t max_length;
>> +	uint32_t supported_encodings;
>> +	uint32_t supported_keyboard;
>> +};
>> +
>> +/* password setting details */
>> +struct tlmi_pwd_setting {
>> +	struct kobject *attr_name_kobj;
>> +	bool valid;
>> +	char display_name[TLMI_PWDTYPE_MAXLEN];
>> +	char password[TLMI_PWD_MAXLEN];
>> +	int minlen;
>> +	int maxlen;
>> +	char encoding[TLMI_ENC_MAXLEN];
>> +	char kbdlang[TLMI_LANG_MAXLEN];
>> +};
>> +
>> +/* Attribute setting details */
>> +struct tlmi_attr_setting {
>> +	struct kobject *attr_name_kobj;
>> +	char display_name[TLMI_SETTINGS_MAXLEN];
>> +	char *possible_values;
>> +};
>> +
>> +struct think_lmi {
>> +	struct wmi_device *wmi_device;
>> +
>> +	int settings_count;
>> +	bool can_set_bios_settings;
>> +	bool can_get_bios_selections;
>> +	bool can_set_bios_password;
>> +	bool can_get_password_settings;
>> +
>> +	struct tlmi_attr_setting *setting[TLMI_SETTINGS_COUNT];
>> +	struct device *class_dev;
>> +	struct kset *attribute_kset;
>> +	struct kset *authentication_kset;
>> +	struct tlmi_pwd_setting *pwd_admin;
>> +	struct tlmi_pwd_setting *pwd_power;
>> +};
>> +
>> +#endif /* !_THINK_LMI_H_ */
>> +
>>
> 
> Regards,
> 
> Hans
> 

Re: [External] Re: [PATCH] platform/x86: think-lmi: Add WMI interface support on Lenovo platforms

[Mark Pearson]

Thanks Hans!

Lots for me to look at :) I didn't have any issues/concerns (or
questions yet) with any of the points so I'll work my way though them
and let you know if anything doesn't work or raises issues.

No problem on the update to firmware-attributes-class update. Makes sense.

Thank you for the thorough review, very much appreciated.

Mark

On 06/05/2021 11:44, Hans de Goede wrote:
> Hi Mark,
> 
> On 4/25/21 5:08 PM, Mark Pearson wrote:
>> For Lenovo platforms that support a WMI interface to the BIOS add
>> support, using the firmware-attributes class, to allow users to access
>> and modify various BIOS related settings.
>>
>> Signed-off-by: Mark Pearson <markpearson@lenovo.com>
> 
> Thank you for this patch, overall it looks good.
> 
> Several small review remarks inline / below.
> 
>> ---
>>  drivers/platform/x86/Kconfig     |   11 +
>>  drivers/platform/x86/Makefile    |    1 +
>>  drivers/platform/x86/think-lmi.c | 1016 ++++++++++++++++++++++++++++++
>>  include/linux/think-lmi.h        |   72 +++
>>  4 files changed, 1100 insertions(+)
>>  create mode 100644 drivers/platform/x86/think-lmi.c
>>  create mode 100644 include/linux/think-lmi.h
>>
>> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
>> index 461ec6153..c26acc211 100644
>> --- a/drivers/platform/x86/Kconfig
>> +++ b/drivers/platform/x86/Kconfig
>> @@ -616,6 +616,17 @@ config THINKPAD_ACPI_HOTKEY_POLL
>>  	  If you are not sure, say Y here.  The driver enables polling only if
>>  	  it is strictly necessary to do so.
>>  
>> +config THINKPAD_LMI
>> +	tristate "Lenovo WMI-based systems management driver"
>> +	default m
>> +	depends on ACPI_WMI
>> +	help
>> +	  This driver allows changing BIOS settings on Lenovo machines whose
>> +	  BIOS support the WMI interface.
>> +
>> +	  To compile this driver as a module, choose M here: the module will
>> +	  be called think-lmi.
>> +
>>  config INTEL_ATOMISP2_LED
>>  	tristate "Intel AtomISP2 camera LED driver"
>>  	depends on GPIOLIB && LEDS_GPIO
>> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
>> index 60d554073..43afc58c9 100644
>> --- a/drivers/platform/x86/Makefile
>> +++ b/drivers/platform/x86/Makefile
>> @@ -60,6 +60,7 @@ obj-$(CONFIG_IBM_RTL)		+= ibm_rtl.o
>>  obj-$(CONFIG_IDEAPAD_LAPTOP)	+= ideapad-laptop.o
>>  obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
>>  obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
>> +obj-$(CONFIG_THINKPAD_LMI)	+= think-lmi.o
>>  
>>  # Intel
>>  obj-$(CONFIG_INTEL_ATOMISP2_LED)	+= intel_atomisp2_led.o
>> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
>> new file mode 100644
>> index 000000000..996f655a2
>> --- /dev/null
>> +++ b/drivers/platform/x86/think-lmi.c
>> @@ -0,0 +1,1016 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * think-lmi.c - Think LMI BIOS configuration driver
>> + *
>> + * Copyright(C) 2019-2021 Lenovo
>> + *
>> + *  Original code from Thinkpad-wmi project https://github.com/iksaif/thinkpad-wmi
>> + *  Copyright(C) 2017 Corentin Chary <corentin.chary@gmail.com>
>> + *  Distributed under the GPL-2.0 license
>> + */
>> +
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/fs.h>
>> +#include <linux/think-lmi.h>
>> +#include <linux/wmi.h>
>> +
>> +/*
>> + * Name:
>> + *  Lenovo_BiosSetting
>> + * Description:
>> + *  Get item name and settings for current LMI instance.
>> + * Type:
>> + *  Query
>> + * Returns:
>> + *  "Item,Value"
>> + * Example:
>> + *  "WakeOnLAN,Enable"
>> + */
>> +#define LENOVO_BIOS_SETTING_GUID "51F5230E-9677-46CD-A1CF-C0B23EE34DB7"
>> +
>> +/*
>> + * Name:
>> + *  Lenovo_SetBiosSetting
>> + * Description:
>> + *  Change the BIOS setting to the desired value using the Lenovo_SetBiosSetting
>> + *  class. To save the settings, use the Lenovo_SaveBiosSetting class.
>> + *  BIOS settings and values are case sensitive.
>> + *  After making changes to the BIOS settings, you must reboot the computer
>> + *  before the changes will take effect.
>> + * Type:
>> + *  Method
>> + * Arguments:
>> + *  "Item,Value,Password,Encoding,KbdLang;"
>> + * Example:
>> + *  "WakeOnLAN,Disable,pswd,ascii,us;"
>> + */
>> +#define LENOVO_SET_BIOS_SETTINGS_GUID "98479A64-33F5-4E33-A707-8E251EBBC3A1"
>> +
>> +/*
>> + * Name:
>> + *  Lenovo_SaveBiosSettings
>> + * Description:
>> + *  Save any pending changes in settings.
>> + * Type:
>> + *  Method
>> + * Arguments:
>> + *  "Password,Encoding,KbdLang;"
>> + * Example:
>> + * "pswd,ascii,us;"
>> + */
>> +#define LENOVO_SAVE_BIOS_SETTINGS_GUID "6A4B54EF-A5ED-4D33-9455-B0D9B48DF4B3"
>> +
>> +/*
>> + * Name:
>> + *  Lenovo_BiosPasswordSettings
>> + * Description:
>> + *  Return BIOS Password settings
>> + * Type:
>> + *  Query
>> + * Returns:
>> + *  PasswordMode, PasswordState, MinLength, MaxLength,
>> + *  SupportedEncoding, SupportedKeyboard
>> + */
>> +#define LENOVO_BIOS_PASSWORD_SETTINGS_GUID "8ADB159E-1E32-455C-BC93-308A7ED98246"
>> +
>> +/*
>> + * Name:
>> + *  Lenovo_SetBiosPassword
>> + * Description:
>> + *  Change a specific password.
>> + *  - BIOS settings cannot be changed at the same boot as power-on
>> + *    passwords (POP) and hard disk passwords (HDP). If you want to change
>> + *    BIOS settings and POP or HDP, you must reboot the system after changing
>> + *    one of them.
>> + *  - A password cannot be set using this method when one does not already
>> + *    exist. Passwords can only be updated or cleared.
>> + * Type:
>> + *  Method
>> + * Arguments:
>> + *  "PasswordType,CurrentPassword,NewPassword,Encoding,KbdLang;"
>> + * Example:
>> + *  "pop,oldpop,newpop,ascii,us;”
>> + */
>> +#define LENOVO_SET_BIOS_PASSWORD_GUID "2651D9FD-911C-4B69-B94E-D0DED5963BD7"
>> +
>> +/*
>> + * Name:
>> + *  Lenovo_GetBiosSelections
>> + * Description:
>> + *  Return a list of valid settings for a given item.
>> + * Type:
>> + *  Method
>> + * Arguments:
>> + *  "Item"
>> + * Returns:
>> + *  "Value1,Value2,Value3,..."
>> + * Example:
>> + *  -> "FlashOverLAN"
>> + *  <- "Enabled,Disabled"
>> + */
>> +#define LENOVO_GET_BIOS_SELECTIONS_GUID	"7364651A-132F-4FE7-ADAA-40C6C7EE2E3B"
>> +
>> +#define TLMI_POP_PWD (1 << 0)
>> +#define TLMI_PAP_PWD (1 << 1)
>> +
>> +/*
>> + * Only add an alias on this one, since it's the one used
>> + * in tlmi_probe
>> + */
>> +MODULE_ALIAS("tlmi:"LENOVO_BIOS_SETTING_GUID);
> 
> I think that this is leftover code from the older version of the driver ?
> 
>> +
>> +static struct class firmware_attributes_class = {
>> +	.name = "firmware-attributes",
>> +};
> 
> Ah yes, so this is a problem. The dell-wmi-sysman code
> also declares and potentialy registers this same class
> (class with the same name).
> 
> Although it is pretty much impossible to load both drivers
> at the same time, I still think it would be best to add
> a small bit of helper code in:
> 
> drivers/platform/x86/firmware_attributes_class.c
> 
> Which takes care of registering the class and can be a
> home for potentially more code sharing in the future.
> 
> This helper code can then be enabled with a hidden
> tristate Kconfig option which then gets selected in
> Kconfig by both the new think-lmi Kconfig option as
> well as by the dell-wmi-sysman Kconfig option.
> 
> Your next version of this series (well now a series)
> should then consist of:
> 
> 1. A patch adding the drivers/platform/x86/firmware_attributes_class.c code
> 2. A patch adjusting dell-wmi-sysman.c to use this for its class registration
>    (compile tested only is fine)
> 3. The patch actually adding the think-lmi driver.
> 
> Sorry for burdoning you with this, but someone needs
> to do this (minor) cleanup before things get messy
> with everyone declaring its own version of the
> firmware-attributes class.
> 
>> +static struct think_lmi tlmi_priv;
>> +
>> +/* ------ Utility functions ------------*/
>> +/* Convert BIOS WMI error string to suitable error code */
>> +static int tlmi_errstr_to_err(const char *errstr)
>> +{
>> +	if (!strcmp(errstr, "Success"))
>> +		/* Operation completed successfully */
>> +		return 0;
>> +	if (!strcmp(errstr, "Not Supported"))
>> +		/* The feature is not supported on this system */
>> +		return -EOPNOTSUPP;
>> +	if (!strcmp(errstr, "Invalid"))
>> +		/* The item or value provided is not valid parameter */
>> +		return -EINVAL;
>> +	if (!strcmp(errstr, "Access Denied"))
>> +		/*
>> +		 * The change could not be made due to an authentication problem.
>> +		 * If a supervisor password exists, the correct supervisor password
>> +		 * must be provided.
>> +		 */
>> +		return -EPERM;
>> +	if (!strcmp(errstr, "System Busy"))
>> +		/*
>> +		 * BIOS changes have already been made that need to be committed.
>> +		 238G* Reboot the system and try again.
>> +		 */
>> +		return -EBUSY;
>> +
>> +	pr_debug("Unknown error string: '%s'", errstr);
>> +	return -EINVAL;
>> +}
>> +
>> +/* Extract error string from WMI return buffer */
>> +static int tlmi_extract_error(const struct acpi_buffer *output)
>> +{
>> +	const union acpi_object *obj;
>> +	int ret;
>> +
>> +	obj = output->pointer;
>> +	if (!obj || obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
>> +		return -EIO;
>> +
>> +	ret = tlmi_errstr_to_err(obj->string.pointer);
>> +	kfree(obj);
> 
> So you kfree the obj here, but what if the earlier checks have
> failed and you return -EIO, you could still have a non NULL kobj
> there, which presumably should be free-ed then ?
> 
>> +	return ret;
>> +}
>> +
>> +/* Utility function to execute WMI call to BIOS */
>> +static int tlmi_simple_call(const char *guid, const char *arg)
>> +{
>> +	const struct acpi_buffer input = { strlen(arg), (char *)arg };
>> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	acpi_status status;
>> +
>> +	/*
>> +	 * duplicated call required to match bios workaround for behavior
>> +	 * seen when WMI accessed via scripting on other OS
>> +	 */
>> +	status = wmi_evaluate_method(guid, 0, 0, &input, &output);
> 
> So what happens to output here ? Maybe free it if necessary
> and re-initialize it to { ACPI_ALLOCATE_BUFFER, NULL }; ?
> 
>> +	status = wmi_evaluate_method(guid, 0, 0, &input, &output);
>> +
>> +	if (ACPI_FAILURE(status))
>> +		return -EIO;
>> +
>> +	return tlmi_extract_error(&output);
>> +}
>> +
>> +/* Extract output string from WMI return buffer */
>> +static int tlmi_extract_output_string(const struct acpi_buffer *output,
>> +					char **string)
>> +{
>> +	const union acpi_object *obj;
>> +
>> +	obj = output->pointer;
>> +	if (!obj || obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
> 
> Again missing a kfree(obj), as with tlmi_extract_error().
> 
>> +		return -EIO;
>> +
>> +	*string = kstrdup(obj->string.pointer, GFP_KERNEL);
>> +	kfree(obj);
>> +	return *string ? 0 : -ENOMEM;
>> +}
>> +
>> +/* ------ Core interface functions ------------*/
>> +
>> +/* Get password settings from BIOS */
>> +static int tlmi_get_pwd_settings(struct tlmi_pwdcfg *pwdcfg)
>> +{
>> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	const union acpi_object *obj;
>> +	acpi_status status;
>> +
>> +	status = wmi_query_block(LENOVO_BIOS_PASSWORD_SETTINGS_GUID, 0,
>> +				 &output);
>> +	if (ACPI_FAILURE(status))
>> +		return -EIO;
>> +
>> +	obj = output.pointer;
>> +	if (!obj || obj->type != ACPI_TYPE_BUFFER || !obj->buffer.pointer)
> 
> Again missing a kfree(obj), as with tlmi_extract_error().
> 
>> +		return -EIO;
>> +	if (obj->buffer.length != sizeof(struct tlmi_pwdcfg)) {
> 
> Replace this with:
> 
> 	if (obj->buffer.length < sizeof(struct tlmi_pwdcfg)) {
> 
> And move the below comment to above the if.
> 
>> +
>> +		/* The size of thinkpad_wmi_pcfg on ThinkStation is larger than ThinkPad.
>> +		 * To make the driver compatible on different brands, we permit it to get
>> +		 * the data in below case.
>> +		 */
> 
>> +		if (obj->buffer.length > sizeof(struct tlmi_pwdcfg)) {
>> +			memcpy(pwdcfg, obj->buffer.pointer, sizeof(struct tlmi_pwdcfg));
>> +			kfree(obj);
>> +			return 0;
>> +		}
> 
> And remove this if block and ...
> 
>> +		pr_warn("Unknown pwdcfg buffer length %d\n", obj->buffer.length);
>> +		kfree(obj);
>> +		return -EIO;
>> +	}
>> +
>> +	memcpy(pwdcfg, obj->buffer.pointer, obj->buffer.length);
> 
> Replace this memcpy with:
> 
> 	memcpy(pwdcfg, obj->buffer.pointer, sizeof(struct tlmi_pwdcfg));
> 
> Would make things a bit cleaner.
> 
>> +	kfree(obj);
>> +	return 0;
>> +}
>> +
>> +static int tlmi_set_bios_settings(const char *settings)
>> +{
>> +	return tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID,
>> +				settings);
>> +}
>> +
>> +static int tlmi_save_bios_settings(const char *password)
>> +{
>> +	return tlmi_simple_call(LENOVO_SAVE_BIOS_SETTINGS_GUID,
>> +				password);
>> +}
>> +
>> +static int tlmi_set_bios_password(char *auth_str)
>> +{
>> +	return tlmi_simple_call(LENOVO_SET_BIOS_PASSWORD_GUID, auth_str);
>> +}
>> +
>> +static int tlmi_setting(int item, char **value, const char *guid_string)
>> +{
>> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	acpi_status status;
>> +
>> +	status = wmi_query_block(guid_string, item, &output);
>> +	if (ACPI_FAILURE(status))
> 
> Again missing a kfree(obj), as with tlmi_extract_error().
> 
>> +		return -EIO;
>> +
>> +	return tlmi_extract_output_string(&output, value);
>> +}
>> +
>> +static int tlmi_get_bios_selections(const char *item, char **value)
>> +{
>> +	const struct acpi_buffer input = { strlen(item), (char *)item };
>> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	acpi_status status;
>> +
>> +	status = wmi_evaluate_method(LENOVO_GET_BIOS_SELECTIONS_GUID,
>> +				     0, 0, &input, &output);
>> +
>> +	if (ACPI_FAILURE(status))
>> +		return -EIO;
>> +
>> +	return tlmi_extract_output_string(&output, value);
>> +}
>> +
>> +/* ---- Authentication sysfs --------------------------------------------------------- */
>> +static struct tlmi_pwd_setting *get_pwd_setting(struct kobject *kobj)
>> +{
>> +	if (strcmp(kobj->name, "Admin") == 0)
>> +		return tlmi_priv.pwd_admin;
>> +	else if (strcmp(kobj->name, "System") == 0)
>> +		return tlmi_priv.pwd_power;
> 
> Below in sysfs_init you create 2 kobject under the authentication
> dir, "Admin" and "System". So IMHO you can simplify this function to just:
> 
> static struct tlmi_pwd_setting *get_pwd_setting(struct kobject *kobj)
> 	if (strcmp(kobj->name, "Admin") == 0)
> 		return tlmi_priv.pwd_admin;
> 	else
> 		return tlmi_priv.pwd_power;
> }
> 
> This has the added advantage of callers not having to check for this
> function returning NULL.
> 
> IMPORTANT NOTE: during the rest of the review I've come up with another
> better solution, see below. So when adjusting this driver, please skip
> making this change and go for the better solution below right away.
> 
>> +	else
>> +		return NULL;
>> +}
>> +
>> +static ssize_t is_enabled_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +					  char *buf)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +
>> +	if (pwd_setting->valid)
>> +		return sysfs_emit(buf, "1\n");
>> +	else
>> +		return sysfs_emit(buf, "0\n");
>> +}
>> +
>> +static struct kobj_attribute auth_is_pass_set = __ATTR_RO(is_enabled);
>> +
>> +static ssize_t current_password_store(struct kobject *kobj,
>> +				      struct kobj_attribute *attr,
>> +				      const char *buf, size_t count)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +	int length;
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change  get_pwd_setting() as suggested above you can drop this check.
> 
>> +
>> +	length = strlen(buf);
>> +	if (buf[length-1] == '\n')
>> +		length--;
>> +
>> +	if (length >= TLMI_PWD_MAXLEN)
>> +		return -EINVAL;
>> +
>> +	memcpy(pwd_setting->password, buf, length);
>> +	pwd_setting->password[length] = '\0';
>> +	return count;
>> +}
>> +
>> +static struct kobj_attribute auth_current_password = __ATTR_WO(current_password);
>> +
>> +static ssize_t new_password_store(struct kobject *kobj,
>> +				  struct kobj_attribute *attr,
>> +				  const char *buf, size_t count)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +	char *p, *new_pwd;
>> +	char pwd_type[4];
>> +	char *auth_str;
>> +	int ret = 0, len;
>> +
>> +	if (!capable(CAP_SYS_ADMIN))
>> +		return -EPERM;
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change get_pwd_setting() as suggested above you can drop this check.
> 
> Shouldn't can_set_bios_password be checked here somewhere?
> 
>> +
>> +	/* Ensure password, kbdlang and encoding has been set */
>> +	if (!strlen(pwd_setting->password)) {
>> +		pr_info("Error: current password not configured\n");
>> +		return -EINVAL;
>> +	}
>> +	if (!strlen(pwd_setting->kbdlang)) {
>> +		pr_info("Error: kbdlang not configured\n");
>> +		return -EINVAL;
>> +	}
> 
> This should probably default to "us" or something like that, so that
> the password interface will just work with the basic mandatory
> auth attributes from: 
> Documentation/ABI/testing/sysfs-class-firmware-attributes
> 
> Without an app using this needing to have knowledge of Lenovo
> specific attributes.
> 
> Oh never-mind, I see that you already specify a default value below,
> but then if you also ensure that this can never be cleared in
> the encoding_store function, then there is no need for this
> len == 0 check here.
> 
> Also the Lenovo specific kbdlang and encoding attributes
> should be documented in:
> Documentation/ABI/testing/sysfs-class-firmware-attributes
> 
> 
>> +	if (!strlen(pwd_setting->encoding)) {
>> +		pr_info("Error: Encoding not configured\n");
>> +		return -EINVAL;
>> +	}
> 
> IMHO it would be better to set a default encoding value in the driver,
> IIRC there is one which is straightforward ascii and one which deals
> with raw-scancodes. IMHO it would be good to default to the ascii
> one, that will also allow to drop this check.
> 
>> +
>> +	new_pwd = kstrdup(buf, GFP_KERNEL);
>> +	if (!new_pwd)
>> +		return -ENOMEM;
>> +	p = memchr(new_pwd, '\n', count);
> 
> strchr ? You are using strdup, so then using memchr after that
> is a bit weird ?
> 
>> +
>> +	if (p != NULL)
>> +		*p = '\0';
>> +	if (strlen(new_pwd) > pwd_setting->maxlen) {
>> +		ret = -EINVAL;
>> +		goto out;
>> +	}
>> +
>> +	if (strcmp(kobj->name, "Admin") == 0)
>> +		sprintf(pwd_type, "pap");
>> +	else
>> +		sprintf(pwd_type, "pop");
> 
> I think it would be cleaner to store the "pap" resp. "pop" strings
> inside the tlmi_pwd_setting struct, rather then repeating the strmcp
> on the kobj->name already done in get_pwd_setting() here ?
> 
>> +
>> +	/* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */
>> +	len = strlen(pwd_setting->password) + strlen(pwd_setting->encoding)
>> +		+ strlen(pwd_setting->kbdlang) + 3 /* type */
>> +		+ strlen(new_pwd) + 6 /* punctuation and terminator*/;
>> +	auth_str = kzalloc(len, GFP_KERNEL);
>> +	snprintf(auth_str, len, "%s,%s,%s,%s,%s;",
>> +		 pwd_type, pwd_setting->password, new_pwd,
>> +		 pwd_setting->encoding, pwd_setting->kbdlang);
>> +	ret = tlmi_set_bios_password(auth_str);
>> +	kfree(auth_str);
>> +out:
>> +	kfree(new_pwd);
>> +	return ret ? ret : count;
>> +}
>> +
>> +static struct kobj_attribute auth_new_password = __ATTR_WO(new_password);
>> +
>> +static ssize_t min_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +			 char *buf)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change get_pwd_setting() as suggested above you can drop this check.
> 
>> +	return sysfs_emit(buf, "%d\n", pwd_setting->minlen);
>> +}
>> +
>> +static struct kobj_attribute auth_min_pass_length = __ATTR_RO(min_password_length);
>> +
>> +static ssize_t max_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +			 char *buf)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change get_pwd_setting() as suggested above you can drop this check.
> 
>> +	return sysfs_emit(buf, "%d\n", pwd_setting->maxlen);
>> +}
>> +static struct kobj_attribute auth_max_pass_length = __ATTR_RO(max_password_length);
>> +
>> +static ssize_t mechanism_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +			 char *buf)
>> +{
>> +	/* Do we need to add scancode here? */
>> +	return sysfs_emit(buf, "password\n");
>> +}
>> +static struct kobj_attribute auth_mechanism = __ATTR_RO(mechanism);
>> +
>> +static ssize_t encoding_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +			 char *buf)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change get_pwd_setting() as suggested above you can drop this check.
> 
>> +
>> +	if (!strlen(pwd_setting->encoding))
>> +		return sysfs_emit(buf, "Not configured\n");
> 
> See above, IMHO the driver should start with a default encoding and
> it should ensure that it always has a valid encoding (see below).
> 
>> +
>> +	return sysfs_emit(buf, "%s\n", pwd_setting->encoding);
>> +}
>> +
>> +static ssize_t encoding_store(struct kobject *kobj,
>> +				  struct kobj_attribute *attr,
>> +				  const char *buf, size_t count)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +	int length;
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change get_pwd_setting() as suggested above you can drop this check.
> 
>> +
>> +	length = strlen(buf);
>> +	if (buf[length-1] == '\n')
>> +		length--;
>> +	if (length >= TLMI_ENC_MAXLEN)
>> +		return -EINVAL;
> 
> IIRC there are only a couple of valid encodings, IMHO it would be
> better to have an array with valid encodings strings and then use
> sysfs_match_string to check if the passed in value is part of the
> array with valid encodings strings. This will also take care of
> the '\n' mess for you.
> 
> You can then also store the index into the array of valid strings
> inside pwd_setting->encoding instead of making pwd_setting->encoding
> a string.
> 
> By storing the index, you can also just make the one which you
> want to be the default the first entry in the array of valid
> encodings strings, so that index 0 is the default.
> 
>> +
>> +	memcpy(pwd_setting->encoding, buf, length);
>> +	pwd_setting->encoding[length] = '\0';
>> +	return count;
>> +}
>> +
>> +static struct kobj_attribute auth_encoding = __ATTR_RW(encoding);
>> +
>> +static ssize_t kbdlang_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +			 char *buf)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> If you change get_pwd_setting() as suggested above you can drop this check.
> 
>> +
>> +	if (!strlen(pwd_setting->kbdlang))
>> +		return sysfs_emit(buf, "Not configured\n");
> 
> Again, please just set a default from the driver.
> 
>> +
>> +	return sysfs_emit(buf, "%s\n", pwd_setting->kbdlang);
>> +}
>> +
>> +static ssize_t kbdlang_store(struct kobject *kobj,
>> +				  struct kobj_attribute *attr,
>> +				  const char *buf, size_t count)
>> +{
>> +	struct tlmi_pwd_setting *pwd_setting = get_pwd_setting(kobj);
>> +	int length;
>> +
>> +	if (!pwd_setting)
>> +		return -EIO;
> 
> Same old, same old.
> 
>> +
>> +	length = strlen(buf);
>> +	if (buf[length-1] == '\n')
>> +		length--;
>> +	if (length >= TLMI_LANG_MAXLEN)
>> +		return -EINVAL;
> 
> And disallow setting an empty value here.
> 
>> +
>> +	memcpy(pwd_setting->kbdlang, buf, length);
>> +	pwd_setting->kbdlang[length] = '\0';
>> +	return count;
>> +}
>> +
>> +static struct kobj_attribute auth_kbdlang = __ATTR_RW(kbdlang);
>> +
>> +static ssize_t role_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +			 char *buf)
>> +{
>> +	if (strcmp(kobj->name, "Admin") == 0)
>> +		return sprintf(buf, "bios-admin\n");
>> +	else if (strcmp(kobj->name, "System") == 0)
>> +		return sprintf(buf, "power-on\n");
>> +	return -EIO;
> 
> Maybe have a const char * pointer for the role inside struct tlmi_pwd_setting
> and use that here ? That would make this function more consistent with
> how the other auth related functions work.
> 
>> +}
>> +static struct kobj_attribute auth_role = __ATTR_RO(role);
>> +
>> +static struct attribute *auth_attrs[] = {
>> +	&auth_is_pass_set.attr,
>> +	&auth_min_pass_length.attr,
>> +	&auth_max_pass_length.attr,
>> +	&auth_current_password.attr,
>> +	&auth_new_password.attr,
>> +	&auth_role.attr,
>> +	&auth_mechanism.attr,
>> +	&auth_encoding.attr,
>> +	&auth_kbdlang.attr,
>> +	NULL,
>> +};
>> +
>> +static const struct attribute_group auth_attr_group = {
>> +	.attrs = auth_attrs,
>> +};
>> +
>> +/* ---- Attributes sysfs --------------------------------------------------------- */
>> +static int get_instance_id(struct kobject *kobj)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i <= tlmi_priv.settings_count; i++) {
>> +		if (tlmi_priv.setting[i]) {
>> +			if (!(strcmp(kobj->name, tlmi_priv.setting[i]->display_name)))
>> +				return i;
>> +		}
>> +	}
>> +	return -EIO;
>> +}
> 
> I believe you don't need this function, see below.
> 
>> +
>> +static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *attr,
>> +		char *buf)
>> +{
>> +	int i = get_instance_id(kobj);
>> +
>> +	if (i < 0)
>> +		return i;
>> +	if (!tlmi_priv.setting[i])
>> +		return -EINVAL;
> 
> This whole lookup dance done here is a bit messy and not necessary, you can make
> things much simpler by changing:
> 
> struct tlmi_attr_setting {
> 	struct kobject *attr_name_kobj;
> 	char display_name[TLMI_SETTINGS_MAXLEN];
> 	char *possible_values;
> };
> 
> To:
> 
> struct tlmi_attr_setting {
> 	struct kobject kobj;
> 	char display_name[TLMI_SETTINGS_MAXLEN];
> 	char *possible_values;
> };
> 
> Note the kobj now no longer is a pointer, it is an embedded struct. This saves you
> from doing (and error checking) a second kzalloc call for this inside ssysfs_init.
> 
> And more importantly you can now use container_of to get a pointer to the struct
> tlmi_attr_setting belonging to the attribute, like this:
> 
> 	struct tlmi_attr_setting *setting = container_of(kobj, struct tlmi_attr_setting, kobj);
> 
> Making the whole function just:
> 
> static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> {
> 	struct tlmi_attr_setting *setting = container_of(kobj, struct tlmi_attr_setting, kobj);
> 
> 	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->display_name);
> }
> 
> Oh and I just realized you can and should do the same for the auth/password functions to
> change the:
> 
> 	struct kobject *attr_name_kobj;
> 
> Inside the struct tlmi_pwd_setting to:
> 
> 	struct kobject kobj;
> 
> And then you can drop the get_pwd_setting() call and replace all it calls with:
> 
> 	struct tlmi_pwd_setting *pwd_setting = container_of(kobj, struct tlmi_pwd_setting, kobj);
> 
> (and drop the NULL pointer checks too).
> 
> 
>> +	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->display_name);
>> +}
>> +
>> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
>> +{
>> +	int i = get_instance_id(kobj);
>> +	char *item;
>> +	int ret;
>> +
>> +	if (i < 0)
>> +		return i;
>> +
>> +	ret = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
> 
> Oh you need i here, interesting, I believe in this case it is best to add
> an int index field to struct tlmi_attr_setting, initialize that field from
> tlmi_analyze() and use that here.
> 
>  
>> +	if (ret)
>> +		return ret;
>> +	ret = sysfs_emit(buf, "%s\n", item);
>> +	kfree(item);
>> +	return ret;
>> +}
>> +
>> +static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
>> +{
>> +	int i = get_instance_id(kobj);
>> +
>> +	if (!tlmi_priv.can_get_bios_selections)
>> +		return -EOPNOTSUPP;
>> +	if (i < 0)
>> +		return i;
>> +	if (!tlmi_priv.setting[i])
>> +		return -EINVAL;
>> +	return sysfs_emit(buf, "%s\n", tlmi_priv.setting[i]->possible_values);
>> +}
> 
> With the suggested change to use an embedded kobj struct, this function will
> also become nice and simple :)
> 
>> +
>> +static ssize_t current_value_store(struct kobject *kobj,
>> +		struct kobj_attribute *attr,
>> +		const char *buf, size_t count)
>> +{
>> +	int i = get_instance_id(kobj);
>> +	int alloc_len, auth_len = 0;
>> +	int str_ix = 0;
>> +	char *auth_str;
>> +	char *set_str;
>> +	int ret;
>> +
>> +	if (i < 0)
>> +		return i;
>> +	if (!tlmi_priv.setting[i])
>> +		return -EINVAL;
> 
> Shouldn't there be some check on can_set_bios_settings here?
> 
> 
>> +
>> +	alloc_len = strlen(tlmi_priv.setting[i]->display_name) + 2 + count;
> 
> This seems to be off by one, you need 1 extra for the , one extra for
> the ; and one extra for the terminating 0.
> 
>> +
>> +	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password) {
>> +		auth_len += strlen(tlmi_priv.pwd_admin->password) + 1
>> +			+ strlen(tlmi_priv.pwd_admin->encoding) + 1
>> +			+ strlen(tlmi_priv.pwd_admin->kbdlang) + 1 + 1;
>> +		auth_str = kmalloc(auth_len, GFP_KERNEL);
>> +		if (!auth_str)
>> +			return -ENOMEM;
>> +
>> +		sprintf(auth_str, "%s,%s,%s;",
>> +				tlmi_priv.pwd_admin->password,
>> +				tlmi_priv.pwd_admin->encoding,
>> +				tlmi_priv.pwd_admin->kbdlang);
>> +		alloc_len += 1 + auth_len;
> 
> I believe you are adding too much to alloc_len here, since
> auth_len already contains space for a terminating 0 and so should
> alloc_len at this point.
> 
>> +	}
>> +
>> +	set_str = kmalloc(alloc_len, GFP_KERNEL);
>> +	if (!set_str) {
>> +		ret = -ENOMEM;
>> +		goto err;
>> +	}
>> +
>> +	str_ix += sprintf(set_str, "%s,", tlmi_priv.setting[i]->display_name);
>> +	str_ix += snprintf(set_str + str_ix, count, "%s", buf);
>> +	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password)
>> +		sprintf(set_str + str_ix - 1, ",%s", auth_str);
>> +	else
>> +		sprintf(set_str + str_ix - 1, ";");
> 
> The str_ix - 1 here looks like it tries to strip a potential \n
> from the passed in buffer, but that if there is no \n there ?
> 
>> +
>> +	ret = tlmi_set_bios_settings(set_str);
>> +	if (ret)
>> +		goto err;
>> +
>> +	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password)
>> +		ret = tlmi_save_bios_settings(auth_str);
>> +	else
>> +		ret = tlmi_save_bios_settings("");
>> +	if (ret)
>> +		goto err;
>> +
>> +	kfree(set_str);
>> +	kfree(auth_str);
>> +	return count;
>> +err:
>> +	kfree(auth_str);
>> +	kfree(set_str);
>> +	return ret;
>> +}
>> +
>> +static struct kobj_attribute attr_displ_name =
>> +		__ATTR_RO(display_name);
>> +
>> +static struct kobj_attribute attr_possible_values =
>> +		__ATTR_RO(possible_values);
>> +
>> +static struct kobj_attribute attr_current_val =
>> +		__ATTR_RW_MODE(current_value, 0600);
>> +
>> +static struct attribute *tlmi_attrs[] = {
>> +	&attr_displ_name.attr,
>> +	&attr_current_val.attr,
>> +	&attr_possible_values.attr,
>> +	NULL,
>> +};
>> +
>> +static const struct attribute_group tlmi_attr_group = {
>> +	.attrs = tlmi_attrs,
>> +};
>> +
>> +static ssize_t tlmi_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 tlmi_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 tlmi_kobj_sysfs_ops = {
>> +	.show	= tlmi_attr_show,
>> +	.store	= tlmi_attr_store,
>> +};
>> +
>> +static void attr_name_release(struct kobject *kobj)
>> +{
>> +	kfree(kobj);
>> +}
> 
> If we switch to embedding the kobjects then we no longer need this
> function, the memory will be free-ed when we free the encapsultating
> structures instead.
> 
>> +
>> +static struct kobj_type attr_name_ktype = {
>> +	.release	= attr_name_release,
> 
> And then we can just leave .release NULL here (IOW drop this line).
> 
>> +	.sysfs_ops	= &tlmi_kobj_sysfs_ops,
>> +};
>> +
>> +/* ---- Initialisation --------------------------------------------------------- */
>> +static void tlmi_release_attr(void)
>> +{
>> +	int i;
>> +
>> +	/* Attribute structures */
>> +	for (i = 0; i < tlmi_priv.settings_count; i++) {
>> +		if (tlmi_priv.setting[i]) {
>> +			kfree(tlmi_priv.setting[i]->possible_values);
>> +
>> +			if (tlmi_priv.setting[i]->attr_name_kobj)
>> +				sysfs_remove_group(tlmi_priv.setting[i]->attr_name_kobj,
>> +						&tlmi_attr_group);
>> +			kfree(tlmi_priv.setting[i]);
>> +		}
>> +	}
>> +	if (tlmi_priv.attribute_kset) {
>> +		struct kobject *pos, *next;
>> +
>> +		list_for_each_entry_safe(pos, next, &tlmi_priv.attribute_kset->list, entry)
>> +			kobject_put(pos);
>> +		kset_unregister(tlmi_priv.attribute_kset);
>> +	}
>> +
>> +	/* Authentication structures */
>> +	if (tlmi_priv.pwd_admin->attr_name_kobj)
>> +		sysfs_remove_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
>> +	kfree(tlmi_priv.pwd_admin);
>> +	if (tlmi_priv.pwd_power->attr_name_kobj)
>> +		sysfs_remove_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
>> +	kfree(tlmi_priv.pwd_power);
>> +	if (tlmi_priv.authentication_kset) {
>> +		struct kobject *pos, *next;
>> +
>> +		list_for_each_entry_safe(pos, next, &tlmi_priv.authentication_kset->list, entry)
>> +			kobject_put(pos);
>> +		kset_unregister(tlmi_priv.authentication_kset);
>> +	}
>> +}
>> +
>> +static int tlmi_sysfs_init(void)
>> +{
>> +	int i, ret;
>> +
>> +	ret = class_register(&firmware_attributes_class);
>> +	if (ret)
>> +		return ret;
>> +
>> +	tlmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
>> +			NULL, "%s", "thinklmi-sysfs");
>> +	if (IS_ERR(tlmi_priv.class_dev)) {
>> +		ret = PTR_ERR(tlmi_priv.class_dev);
>> +		goto fail_class_created;
>> +	}
>> +
>> +	tlmi_priv.attribute_kset = kset_create_and_add("attributes", NULL,
>> +			&tlmi_priv.class_dev->kobj);
>> +	if (!tlmi_priv.attribute_kset) {
>> +		ret = -ENOMEM;
>> +		goto fail_device_created;
>> +	}
>> +
>> +	for (i = 0; i < tlmi_priv.settings_count; ++i) {
>> +		/*Check if index is a valid setting - skip if it isn't */
>> +		if (!tlmi_priv.setting[i])
>> +			continue;
>> +
>> +		/* build attribute */
>> +		tlmi_priv.setting[i]->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
>> +		if (!tlmi_priv.setting[i]->attr_name_kobj) {
>> +			ret = -ENOMEM;
>> +			goto fail_create_attr;
>> +		}
>> +		tlmi_priv.setting[i]->attr_name_kobj->kset = tlmi_priv.attribute_kset;
>> +
>> +		ret = kobject_init_and_add(tlmi_priv.setting[i]->attr_name_kobj, &attr_name_ktype,
>> +				NULL, "%s", tlmi_priv.setting[i]->display_name);
>> +		if (ret)
>> +			goto fail_create_attr;
>> +
>> +		ret = sysfs_create_group(tlmi_priv.setting[i]->attr_name_kobj, &tlmi_attr_group);
>> +		if (ret)
>> +			goto fail_create_attr;
>> +	}
>> +
>> +	/* Create authentication entries */
>> +	tlmi_priv.authentication_kset = kset_create_and_add("authentication", NULL,
>> +								&tlmi_priv.class_dev->kobj);
>> +	if (!tlmi_priv.authentication_kset) {
>> +		ret = -ENOMEM;
>> +		goto fail_create_attr;
>> +	}
>> +	tlmi_priv.pwd_admin->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_admin->attr_name_kobj) {
>> +		ret = -ENOMEM;
>> +		goto fail_create_attr;
>> +	}
>> +	tlmi_priv.pwd_admin->attr_name_kobj->kset = tlmi_priv.authentication_kset;
>> +	ret = kobject_init_and_add(tlmi_priv.pwd_admin->attr_name_kobj, &attr_name_ktype,
>> +			NULL, "%s", "Admin");
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	ret = sysfs_create_group(tlmi_priv.pwd_admin->attr_name_kobj, &auth_attr_group);
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	tlmi_priv.pwd_power->attr_name_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_power->attr_name_kobj) {
>> +		ret = -ENOMEM;
>> +		goto fail_create_attr;
>> +	}
>> +	tlmi_priv.pwd_power->attr_name_kobj->kset = tlmi_priv.authentication_kset;
>> +	ret = kobject_init_and_add(tlmi_priv.pwd_power->attr_name_kobj, &attr_name_ktype,
>> +			NULL, "%s", "System");
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	ret = sysfs_create_group(tlmi_priv.pwd_power->attr_name_kobj, &auth_attr_group);
>> +	if (ret)
>> +		goto fail_create_attr;
>> +
>> +	return ret;
>> +
>> +fail_create_attr:
>> +	tlmi_release_attr();
>> +fail_device_created:
>> +	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
>> +fail_class_created:
>> +	class_unregister(&firmware_attributes_class);
>> +	return ret;
>> +}
>> +
>> +static void tlmi_sysfs_exit(void)
>> +{
>> +	tlmi_release_attr();
>> +	device_destroy(&firmware_attributes_class, MKDEV(0, 0));
>> +	class_unregister(&firmware_attributes_class);
>> +}
>> +
>> +/* ---- Base Driver -------------------------------------------------------- */
>> +static int tlmi_analyze(void)
>> +{
>> +	struct tlmi_pwdcfg pwdcfg;
>> +	acpi_status status;
>> +	int i = 0;
>> +	int ret;
>> +
>> +	if (wmi_has_guid(LENOVO_SET_BIOS_SETTINGS_GUID) &&
>> +	    wmi_has_guid(LENOVO_SAVE_BIOS_SETTINGS_GUID))
>> +		tlmi_priv.can_set_bios_settings = true;
>> +
>> +	if (wmi_has_guid(LENOVO_GET_BIOS_SELECTIONS_GUID))
>> +		tlmi_priv.can_get_bios_selections = true;
>> +
>> +	if (wmi_has_guid(LENOVO_SET_BIOS_PASSWORD_GUID))
>> +		tlmi_priv.can_set_bios_password = true;
>> +
>> +	if (wmi_has_guid(LENOVO_BIOS_PASSWORD_SETTINGS_GUID))
>> +		tlmi_priv.can_get_password_settings = true;
>> +
>> +	/*
>> +	 * Try to find the number of valid settings of this machine
>> +	 * and use it to create sysfs attributes
>> +	 */
>> +	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i) {
>> +		char *item = NULL;
>> +		int spleng = 0;
>> +		int num = 0;
>> +		char *p;
>> +		struct tlmi_attr_setting *setting;
>> +
>> +		tlmi_priv.setting[i] = NULL;
>> +		status = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
>> +		if (ACPI_FAILURE(status))
>> +			break;
>> +		if (!item)
>> +			break;
>> +		if (!*item)
>> +			continue;
>> +
>> +		/* It is not allowed to have '/' for file name. Convert it into '\'. */
>> +		spleng = strlen(item);
>> +		for (num = 0; num < spleng; num++) {
>> +			if (item[num] == '/')
>> +				item[num] = '\\';
>> +		}
>> +
>> +		/* Remove the value part */
>> +		p = strchr(item, ',');
>> +		if (p)
>> +			*p = '\0';
>> +
>> +		/* Create a setting entry */
>> +		setting = kzalloc(sizeof(struct tlmi_attr_setting), GFP_KERNEL);
>> +		if (!setting) {
>> +			ret = -ENOMEM;
>> +			goto fail_clear_attr;
>> +		}
>> +		strscpy(setting->display_name, item, TLMI_SETTINGS_MAXLEN);
>> +
>> +		/* If BIOS selections supported, load those */
>> +		if (tlmi_priv.can_get_bios_selections) {
>> +			ret = tlmi_get_bios_selections(setting->display_name,
>> +					&setting->possible_values);
>> +			if (ret || !setting->possible_values)
>> +				pr_info("Error retrieving possible values for %d : %s\n",
>> +						i, setting->display_name);
>> +		}
>> +		tlmi_priv.setting[i] = setting;
>> +		tlmi_priv.settings_count++;
>> +		kfree(item);
>> +	}
>> +
>> +	/* Create password setting structure */
>> +	ret = tlmi_get_pwd_settings(&pwdcfg);
>> +	if (ret)
>> +		goto fail_clear_attr;
>> +
>> +	tlmi_priv.pwd_admin = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_admin) {
>> +		ret = -ENOMEM;
>> +		goto fail_clear_attr;
>> +	}
>> +	sprintf(tlmi_priv.pwd_admin->display_name, "admin");
>> +	sprintf(tlmi_priv.pwd_admin->kbdlang, "us");
>> +	sprintf(tlmi_priv.pwd_admin->encoding, "ascii");
>> +	tlmi_priv.pwd_admin->minlen = pwdcfg.min_length;
>> +	tlmi_priv.pwd_admin->maxlen = pwdcfg.max_length;
>> +	if (pwdcfg.password_state & TLMI_PAP_PWD)
>> +		tlmi_priv.pwd_admin->valid = true;
>> +
>> +	tlmi_priv.pwd_power = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
>> +	if (!tlmi_priv.pwd_power) {
>> +		ret = -ENOMEM;
>> +		goto fail_clear_attr;
>> +	}
>> +	sprintf(tlmi_priv.pwd_power->display_name, "power-on");
>> +	sprintf(tlmi_priv.pwd_power->kbdlang, "us");
>> +	sprintf(tlmi_priv.pwd_power->encoding, "ascii");
>> +	tlmi_priv.pwd_power->minlen = pwdcfg.min_length;
>> +	tlmi_priv.pwd_power->maxlen = pwdcfg.max_length;
>> +
>> +	if (pwdcfg.password_state & TLMI_POP_PWD)
>> +		tlmi_priv.pwd_power->valid = true;
>> +
>> +	return 0;
>> +
>> +fail_clear_attr:
>> +	for (i = 0; i < TLMI_SETTINGS_COUNT; ++i)
>> +		kfree(tlmi_priv.setting[i]);
>> +	return ret;
>> +}
>> +
>> +static int tlmi_remove(struct wmi_device *wdev)
>> +{
>> +	tlmi_sysfs_exit();
>> +	return 0;
>> +}
>> +
>> +static int tlmi_probe(struct wmi_device *wdev, const void *context)
>> +{
>> +	tlmi_analyze();
>> +	return tlmi_sysfs_init();
>> +}
>> +
>> +static const struct wmi_device_id tlmi_id_table[] = {
>> +	{ .guid_string = LENOVO_BIOS_SETTING_GUID },
>> +	{ }
>> +};
>> +
>> +static struct wmi_driver tlmi_driver = {
>> +	.driver = {
>> +		.name = "think-lmi",
>> +	},
>> +	.id_table = tlmi_id_table,
>> +	.probe = tlmi_probe,
>> +	.remove = tlmi_remove,
>> +};
>> +
>> +static int __init tlmi_init(void)
>> +{
>> +	return wmi_driver_register(&tlmi_driver);
>> +}
>> +
>> +static void __exit tlmi_exit(void)
>> +{
>> +	wmi_driver_unregister(&tlmi_driver);
>> +}
> 
> You can replace the declaration of these functions + the
> module_init and module_exit calls below with a single
> 
> module_wmi_driver(tlmi_driver);
> 
> "call".
> 
> 
>> +
>> +MODULE_AUTHOR("Sugumaran L <slacshiminar@lenovo.com>");
>> +MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
>> +MODULE_AUTHOR("Corentin Chary <corentin.chary@gmail.com>");
>> +MODULE_DESCRIPTION("ThinkLMI Driver");
>> +MODULE_LICENSE("GPL");
>> +
>> +module_init(tlmi_init);
>> +module_exit(tlmi_exit);
>> diff --git a/include/linux/think-lmi.h b/include/linux/think-lmi.h
>> new file mode 100644
>> index 000000000..9133c0567
>> --- /dev/null
>> +++ b/include/linux/think-lmi.h
>> @@ -0,0 +1,72 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +
>> +#ifndef _THINK_LMI_H_
>> +#define _THINK_LMI_H_
>> +
>> +#define TLMI_SETTINGS_COUNT  256
>> +#define TLMI_SETTINGS_MAXLEN 512
>> +#define TLMI_PWD_MAXLEN       64
>> +#define TLMI_PWDTYPE_MAXLEN   64
>> +#define TLMI_ENC_MAXLEN       64
>> +#define TLMI_LANG_MAXLEN       4
>> +/*
>> + * Longest string should be in the set command: allow size of BIOS
>> + * option and choice
>> + */
>> +#define TLMI_GETSET_MAXLEN (TLMI_SETTINGS_MAXLEN + TLMI_SETTINGS_MAXLEN)
>> +
>> +#define THINKLMI_GET_SETTINGS _IOR('T', 1, int *)
>> +#define THINKLMI_GET_SETTINGS_STRING _IOWR('T', 2, char *)
>> +#define THINKLMI_SET_SETTING _IOW('T', 3, char *)
>> +#define THINKLMI_SHOW_SETTING _IOWR('T', 4, char *)
>> +#define THINKLMI_AUTHENTICATE _IOW('T', 5, char *)
>> +#define THINKLMI_CHANGE_PASSWORD _IOW('T', 6, char *)
> 
> These defines seem to be a left-over from when the think-lmi driver
> was providing an ioctl interface, please drop these.
> 
>> +
>> +/* password configuration details */
>> +struct tlmi_pwdcfg {
>> +	uint32_t password_mode;
>> +	uint32_t password_state;
>> +	uint32_t min_length;
>> +	uint32_t max_length;
>> +	uint32_t supported_encodings;
>> +	uint32_t supported_keyboard;
>> +};
>> +
>> +/* password setting details */
>> +struct tlmi_pwd_setting {
>> +	struct kobject *attr_name_kobj;
>> +	bool valid;
>> +	char display_name[TLMI_PWDTYPE_MAXLEN];
>> +	char password[TLMI_PWD_MAXLEN];
>> +	int minlen;
>> +	int maxlen;
>> +	char encoding[TLMI_ENC_MAXLEN];
>> +	char kbdlang[TLMI_LANG_MAXLEN];
>> +};
>> +
>> +/* Attribute setting details */
>> +struct tlmi_attr_setting {
>> +	struct kobject *attr_name_kobj;
>> +	char display_name[TLMI_SETTINGS_MAXLEN];
>> +	char *possible_values;
>> +};
>> +
>> +struct think_lmi {
>> +	struct wmi_device *wmi_device;
>> +
>> +	int settings_count;
>> +	bool can_set_bios_settings;
>> +	bool can_get_bios_selections;
>> +	bool can_set_bios_password;
>> +	bool can_get_password_settings;
>> +
>> +	struct tlmi_attr_setting *setting[TLMI_SETTINGS_COUNT];
>> +	struct device *class_dev;
>> +	struct kset *attribute_kset;
>> +	struct kset *authentication_kset;
>> +	struct tlmi_pwd_setting *pwd_admin;
>> +	struct tlmi_pwd_setting *pwd_power;
>> +};
>> +
>> +#endif /* !_THINK_LMI_H_ */
>> +
>>
> 
> Regards,
> 
> Hans
>