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Message-ID: <ZQhXZkBHviGOEl-x@smile.fi.intel.com>
Date: Mon, 18 Sep 2023 16:57:58 +0300
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Mark Pearson <mpearson-lenovo@...ebb.ca>
Cc: hdegoede@...hat.com, markgross@...nel.org,
platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] platform/x86: think-lmi: Add bulk save feature
On Wed, Sep 06, 2023 at 08:13:14AM -0400, Mark Pearson wrote:
> On Lenovo platforms there is a limitation in the number of times an
> attribute can be saved. This is an architectural limitation and it limits
> the number of attributes that can be modified to 48.
> A solution for this is instead of the attribute being saved after every
> modification allow a user to bulk set the attributes and then trigger a
> final save. This allows unlimited attributes.
>
> This patch introduces a save_settings attribute that can be configured to
> either single or bulk mode by the user.
> Single mode is the default but customers who want to avoid the 48
> attribute limit can enable bulk mode.
>
> Displaying the save_settings attribute will display the enabled mode.
>
> When in bulk mode writing 'save' to the save_settings attribute will
> trigger a save. Once this has been done a reboot is required before more
> attributes can be modified.
...
> +Date: August 2023
> +KernelVersion: 6.5
This is obviously incorrect (outdated) information.
...
> +static const char * const save_mode_strings[] = {
> + [TLMI_SAVE_SINGLE] = "single",
> + [TLMI_SAVE_BULK] = "bulk",
> + [TLMI_SAVE_SAVE] = "save"
Missing comma.
> +};
...
> +static ssize_t save_settings_show(struct kobject *kobj, struct kobj_attribute *attr,
> + char *buf)
> +{
> + /* Check that setting is valid */
> + if (WARN_ON((tlmi_priv.save_mode < TLMI_SAVE_SINGLE) ||
> + (tlmi_priv.save_mode > TLMI_SAVE_BULK)))
> + return -EIO;
> + return sprintf(buf, "%s\n", save_mode_strings[tlmi_priv.save_mode]);
According to the documentation it must be sysfs_emit() if I'm not missing
anything here.
> +}
...
> +static ssize_t save_settings_store(struct kobject *kobj, struct kobj_attribute *attr,
> + const char *buf, size_t count)
> +{
> + char *auth_str = NULL;
> + int ret = 0;
> + int cmd;
> +
> + cmd = sysfs_match_string(save_mode_strings, buf);
> +
> + /* Use lock in case multiple WMI operations needed */
> + mutex_lock(&tlmi_mutex);
> +
> + switch (cmd) {
> + case TLMI_SAVE_SINGLE:
> + case TLMI_SAVE_BULK:
> + tlmi_priv.save_mode = cmd;
> + goto out;
> + case TLMI_SAVE_SAVE:
> + /* Check if supported*/
> + if ((!tlmi_priv.can_set_bios_settings) ||
> + (tlmi_priv.save_mode == TLMI_SAVE_SINGLE)) {
> + ret = -EOPNOTSUPP;
> + goto out;
> + }
> + /* Check there is actually something to save */
> + if (!tlmi_priv.save_required) {
> + ret = -ENOENT;
> + goto out;
> + }
> + /* Check if certificate authentication is enabled and active */
> + if (tlmi_priv.certificate_support && tlmi_priv.pwd_admin->cert_installed) {
> + if (!tlmi_priv.pwd_admin->signature ||
> + !tlmi_priv.pwd_admin->save_signature) {
> + ret = -EINVAL;
> + goto out;
> + }
> + ret = tlmi_simple_call(LENOVO_SAVE_BIOS_SETTING_CERT_GUID,
> + tlmi_priv.pwd_admin->save_signature);
> + if (ret)
> + goto out;
> + } else if (tlmi_priv.opcode_support) {
> + if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
> + ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin",
> + tlmi_priv.pwd_admin->password);
> + if (ret)
> + goto out;
> + }
> + ret = tlmi_save_bios_settings("");
> + } else { /* old non-opcode based authentication method (deprecated) */
> + if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
> + auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;",
> + tlmi_priv.pwd_admin->password,
> + encoding_options[tlmi_priv.pwd_admin->encoding],
> + tlmi_priv.pwd_admin->kbdlang);
> + if (!auth_str) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + }
> +
> + if (auth_str)
> + ret = tlmi_save_bios_settings(auth_str);
> + else
> + ret = tlmi_save_bios_settings("");
> + }
> + tlmi_priv.save_required = false;
> + tlmi_priv.reboot_required = true;
> +
> + if (!ret && !tlmi_priv.pending_changes) {
> + tlmi_priv.pending_changes = true;
> + /* let userland know it may need to check reboot pending again */
> + kobject_uevent(&tlmi_priv.class_dev->kobj, KOBJ_CHANGE);
> + }
> + break;
> + default:
> + ret = -EINVAL;
> + }
Missing break; and actually no need to do this part under the lock, besides
that it shadows an error code, that said this should be
cmd = sysfs_match_string(...);
if (cmd < 0)
return cmd;
> +out:
> + mutex_unlock(&tlmi_mutex);
> + kfree(auth_str);
> + return ret ?: count;
You can switch the driver to use cleanup.h at some point.
> +}
...
> +/* There are a limit on the number of WMI operations you can do if you use
> + * the default implementation of saving on every set. This is due to a
> + * limitation in EFI variable space used.
> + * Have a 'bulk save' mode where you can manually trigger the save, and can
> + * therefore set unlimited variables - for users that need it.
> + */
/*
* This is wrong multi-line comment style. This one
* is used solely in net subsystem.
*/
--
With Best Regards,
Andy Shevchenko
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