Hi, On 8/17/21 2:15 AM, Mark Pearson wrote: > Many Lenovo BIOS's support the ability to send a debug command which > is useful for debugging and testing unreleased or early features. > > Adding support for this feature as a module parameter. > > Signed-off-by: Mark Pearson <markpearson@xxxxxxxxxx> > --- > Changes in v2: > - Updated to use debug_support parameter to enable feature > - remove changes to pending_reboot as that was integrated separately > > .../testing/sysfs-class-firmware-attributes | 11 +++ > drivers/platform/x86/think-lmi.c | 80 +++++++++++++++++++ > drivers/platform/x86/think-lmi.h | 1 + > 3 files changed, 92 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-class-firmware-attributes b/Documentation/ABI/testing/sysfs-class-firmware-attributes > index 0b43997b76e3..90fdf935aa5e 100644 > --- a/Documentation/ABI/testing/sysfs-class-firmware-attributes > +++ b/Documentation/ABI/testing/sysfs-class-firmware-attributes > @@ -272,3 +272,14 @@ Description: > > Note that any changes to this attribute requires a reboot > for changes to take effect. > + > +What: /sys/class/firmware-attributes/*/attributes/debug_cmd > +Date: July 2021 > +KernelVersion: 5.14 > +Contact: Mark Pearson <markpearson@xxxxxxxxxx> > +Description: > + This write only attribute can be used to send debug commands to the BIOS. > + This should only be used when recommended by the BIOS vendor. Vendors may > + use it to enable extra debug attributes or BIOS features for testing purposes. > + > + Note that any changes to this attribute requires a reboot for changes to take effect. > diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c > index 6cfed4427fb0..4d246bfe4907 100644 > --- a/drivers/platform/x86/think-lmi.c > +++ b/drivers/platform/x86/think-lmi.c > @@ -20,6 +20,10 @@ > #include "firmware_attributes_class.h" > #include "think-lmi.h" > > +static bool debug_support; > +module_param(debug_support, bool, 0644); 0644 implies the setting can be changed at runtime, but it is checked only at driver bind + unbind time, so this should be 0444. Since the rest of the patch looks good, I've fixed this up while merging the patch. ### Thank you for your patch, I've applied this patch to my review-hans branch: https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans Once I've run some tests on this branch the patches there will be added to the platform-drivers-x86/for-next branch and eventually will be included in the pdx86 pull-request to Linus for the next merge-window. Regards, Hans > +MODULE_PARM_DESC(debug_support, "Enable debug command support"); > + > /* > * Name: > * Lenovo_BiosSetting > @@ -116,6 +120,14 @@ > */ > #define LENOVO_GET_BIOS_SELECTIONS_GUID "7364651A-132F-4FE7-ADAA-40C6C7EE2E3B" > > +/* > + * Name: > + * Lenovo_DebugCmdGUID > + * Description > + * Debug entry GUID method for entering debug commands to the BIOS > + */ > +#define LENOVO_DEBUG_CMD_GUID "7FF47003-3B6C-4E5E-A227-E979824A85D1" > + > #define TLMI_POP_PWD (1 << 0) > #define TLMI_PAP_PWD (1 << 1) > #define to_tlmi_pwd_setting(kobj) container_of(kobj, struct tlmi_pwd_setting, kobj) > @@ -660,6 +672,64 @@ static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute * > > static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot); > > +/* ---- Debug interface--------------------------------------------------------- */ > +static ssize_t debug_cmd_store(struct kobject *kobj, struct kobj_attribute *attr, > + const char *buf, size_t count) > +{ > + char *set_str = NULL, *new_setting = NULL; > + char *auth_str = NULL; > + char *p; > + int ret; > + > + if (!tlmi_priv.can_debug_cmd) > + return -EOPNOTSUPP; > + > + new_setting = kstrdup(buf, GFP_KERNEL); > + if (!new_setting) > + return -ENOMEM; > + > + /* Strip out CR if one is present */ > + p = strchrnul(new_setting, '\n'); > + *p = '\0'; > + > + 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) > + set_str = kasprintf(GFP_KERNEL, "%s,%s", new_setting, auth_str); > + else > + set_str = kasprintf(GFP_KERNEL, "%s;", new_setting); > + if (!set_str) { > + ret = -ENOMEM; > + goto out; > + } > + > + ret = tlmi_simple_call(LENOVO_DEBUG_CMD_GUID, set_str); > + if (ret) > + goto out; > + > + 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); > + } > +out: > + kfree(auth_str); > + kfree(set_str); > + kfree(new_setting); > + return ret ?: count; > +} > + > +static struct kobj_attribute debug_cmd = __ATTR_WO(debug_cmd); > + > /* ---- Initialisation --------------------------------------------------------- */ > static void tlmi_release_attr(void) > { > @@ -673,6 +743,8 @@ static void tlmi_release_attr(void) > } > } > sysfs_remove_file(&tlmi_priv.attribute_kset->kobj, &pending_reboot.attr); > + if (tlmi_priv.can_debug_cmd && debug_support) > + sysfs_remove_file(&tlmi_priv.attribute_kset->kobj, &debug_cmd.attr); > kset_unregister(tlmi_priv.attribute_kset); > > /* Authentication structures */ > @@ -737,6 +809,11 @@ static int tlmi_sysfs_init(void) > if (ret) > goto fail_create_attr; > > + if (tlmi_priv.can_debug_cmd && debug_support) { > + ret = sysfs_create_file(&tlmi_priv.attribute_kset->kobj, &debug_cmd.attr); > + if (ret) > + goto fail_create_attr; > + } > /* Create authentication entries */ > tlmi_priv.authentication_kset = kset_create_and_add("authentication", NULL, > &tlmi_priv.class_dev->kobj); > @@ -793,6 +870,9 @@ static int tlmi_analyze(void) > if (wmi_has_guid(LENOVO_BIOS_PASSWORD_SETTINGS_GUID)) > tlmi_priv.can_get_password_settings = true; > > + if (wmi_has_guid(LENOVO_DEBUG_CMD_GUID)) > + tlmi_priv.can_debug_cmd = true; > + > /* > * Try to find the number of valid settings of this machine > * and use it to create sysfs attributes. > diff --git a/drivers/platform/x86/think-lmi.h b/drivers/platform/x86/think-lmi.h > index eb598846628a..f8e26823075f 100644 > --- a/drivers/platform/x86/think-lmi.h > +++ b/drivers/platform/x86/think-lmi.h > @@ -61,6 +61,7 @@ struct think_lmi { > bool can_set_bios_password; > bool can_get_password_settings; > bool pending_changes; > + bool can_debug_cmd; > > struct tlmi_attr_setting *setting[TLMI_SETTINGS_COUNT]; > struct device *class_dev; >
