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);
+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;
--
2.31.1
