drm/xe: Validate wedged_mode parameter and define enum for modes

Check correctness of the wedged_mode parameter input to ensure only
supported values are accepted. Additionally, replace magic numbers with
a clearly defined enum.

Signed-off-by: Lukasz Laguna <lukasz.laguna@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/20260107174741.29163-2-lukasz.laguna@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_debugfs.c

@@ -267,8 +267,9 @@ static ssize_t wedged_mode_set(struct file *f, const char __user *ubuf,
 	if (ret)
 		return ret;
 
-	if (wedged_mode > 2)
-		return -EINVAL;
+	ret = xe_device_validate_wedged_mode(xe, wedged_mode);
+	if (ret)
+		return ret;
 
 	if (xe->wedged.mode == wedged_mode)
 		return size;

drivers/gpu/drm/xe/xe_device.c

@@ -784,7 +784,10 @@ int xe_device_probe_early(struct xe_device *xe)
 	if (err)
 		return err;
 
-	xe->wedged.mode = xe_modparam.wedged_mode;
+	xe->wedged.mode = xe_device_validate_wedged_mode(xe, xe_modparam.wedged_mode) ?
+			  XE_WEDGED_MODE_DEFAULT : xe_modparam.wedged_mode;
+	drm_dbg(&xe->drm, "wedged_mode: setting mode (%u) %s\n",
+		xe->wedged.mode, xe_wedged_mode_to_string(xe->wedged.mode));
 
 	err = xe_device_vram_alloc(xe);
 	if (err)
@@ -1267,10 +1270,10 @@ static void xe_device_wedged_fini(struct drm_device *drm, void *arg)
  * DOC: Xe Device Wedging
  *
  * Xe driver uses drm device wedged uevent as documented in Documentation/gpu/drm-uapi.rst.
- * When device is in wedged state, every IOCTL will be blocked and GT cannot be
- * used. Certain critical errors like gt reset failure, firmware failures can cause
- * the device to be wedged. The default recovery method for a wedged state
- * is rebind/bus-reset.
+ * When device is in wedged state, every IOCTL will be blocked and GT cannot
+ * be used. The conditions under which the driver declares the device wedged
+ * depend on the wedged mode configuration (see &enum xe_wedged_mode). The
+ * default recovery method for a wedged state is rebind/bus-reset.
  *
  * Another recovery method is vendor-specific. Below are the cases that send
  * ``WEDGED=vendor-specific`` recovery method in drm device wedged uevent.
@@ -1335,7 +1338,7 @@ void xe_device_declare_wedged(struct xe_device *xe)
 	struct xe_gt *gt;
 	u8 id;
 
-	if (xe->wedged.mode == 0) {
+	if (xe->wedged.mode == XE_WEDGED_MODE_NEVER) {
 		drm_dbg(&xe->drm, "Wedged mode is forcibly disabled\n");
 		return;
 	}
@@ -1369,3 +1372,42 @@ void xe_device_declare_wedged(struct xe_device *xe)
 		drm_dev_wedged_event(&xe->drm, xe->wedged.method, NULL);
 	}
 }
+
+/**
+ * xe_device_validate_wedged_mode - Check if given mode is supported
+ * @xe: the &xe_device
+ * @mode: requested mode to validate
+ *
+ * Check whether the provided wedged mode is supported.
+ *
+ * Return: 0 if mode is supported, error code otherwise.
+ */
+int xe_device_validate_wedged_mode(struct xe_device *xe, unsigned int mode)
+{
+	if (mode > XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET) {
+		drm_dbg(&xe->drm, "wedged_mode: invalid value (%u)\n", mode);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * xe_wedged_mode_to_string - Convert enum value to string.
+ * @mode: the &xe_wedged_mode to convert
+ *
+ * Returns: wedged mode as a user friendly string.
+ */
+const char *xe_wedged_mode_to_string(enum xe_wedged_mode mode)
+{
+	switch (mode) {
+	case XE_WEDGED_MODE_NEVER:
+		return "never";
+	case XE_WEDGED_MODE_UPON_CRITICAL_ERROR:
+		return "upon-critical-error";
+	case XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET:
+		return "upon-any-hang-no-reset";
+	default:
+		return "<invalid>";
+	}
+}

drivers/gpu/drm/xe/xe_device.h

@@ -194,6 +194,8 @@ static inline bool xe_device_wedged(struct xe_device *xe)
 
 void xe_device_set_wedged_method(struct xe_device *xe, unsigned long method);
 void xe_device_declare_wedged(struct xe_device *xe);
+int xe_device_validate_wedged_mode(struct xe_device *xe, unsigned int mode);
+const char *xe_wedged_mode_to_string(enum xe_wedged_mode mode);
 
 struct xe_file *xe_file_get(struct xe_file *xef);
 void xe_file_put(struct xe_file *xef);

drivers/gpu/drm/xe/xe_device_types.h

@@ -46,6 +46,25 @@ struct xe_pat_ops;
 struct xe_pxp;
 struct xe_vram_region;
 
+/**
+ * enum xe_wedged_mode - possible wedged modes
+ * @XE_WEDGED_MODE_NEVER: Device will never be declared wedged.
+ * @XE_WEDGED_MODE_UPON_CRITICAL_ERROR: Device will be declared wedged only
+ *	when critical error occurs like GT reset failure or firmware failure.
+ *	This is the default mode.
+ * @XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET: Device will be declared wedged on
+ *	any hang. In this mode, engine resets are disabled to avoid automatic
+ *	recovery attempts. This mode is primarily intended for debugging hangs.
+ */
+enum xe_wedged_mode {
+	XE_WEDGED_MODE_NEVER = 0,
+	XE_WEDGED_MODE_UPON_CRITICAL_ERROR = 1,
+	XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET = 2,
+};
+
+#define XE_WEDGED_MODE_DEFAULT		XE_WEDGED_MODE_UPON_CRITICAL_ERROR
+#define XE_WEDGED_MODE_DEFAULT_STR	"upon-critical-error"
+
 #define XE_BO_INVALID_OFFSET	LONG_MAX
 
 #define GRAPHICS_VER(xe) ((xe)->info.graphics_verx100 / 100)
@@ -626,7 +645,7 @@ struct xe_device {
 		/** @wedged.flag: Xe device faced a critical error and is now blocked. */
 		atomic_t flag;
 		/** @wedged.mode: Mode controlled by kernel parameter and debugfs */
-		int mode;
+		enum xe_wedged_mode mode;
 		/** @wedged.method: Recovery method to be sent in the drm device wedged uevent */
 		unsigned long method;
 	} wedged;

drivers/gpu/drm/xe/xe_guc_ads.c

@@ -451,7 +451,7 @@ static void guc_policies_init(struct xe_guc_ads *ads)
 	ads_blob_write(ads, policies.max_num_work_items,
 		       GLOBAL_POLICY_MAX_NUM_WI);
 
-	if (xe->wedged.mode == 2)
+	if (xe->wedged.mode == XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET)
 		global_flags |= GLOBAL_POLICY_DISABLE_ENGINE_RESET;
 
 	ads_blob_write(ads, policies.global_flags, global_flags);
@@ -1004,7 +1004,7 @@ int xe_guc_ads_scheduler_policy_toggle_reset(struct xe_guc_ads *ads)
 	policies->dpc_promote_time = ads_blob_read(ads, policies.dpc_promote_time);
 	policies->max_num_work_items = ads_blob_read(ads, policies.max_num_work_items);
 	policies->is_valid = 1;
-	if (xe->wedged.mode == 2)
+	if (xe->wedged.mode == XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET)
 		policies->global_flags |= GLOBAL_POLICY_DISABLE_ENGINE_RESET;
 	else
 		policies->global_flags &= ~GLOBAL_POLICY_DISABLE_ENGINE_RESET;

drivers/gpu/drm/xe/xe_guc_capture.c

@@ -1889,7 +1889,14 @@ xe_guc_capture_get_matching_and_lock(struct xe_exec_queue *q)
 		return NULL;
 
 	xe = gt_to_xe(q->gt);
-	if (xe->wedged.mode >= 2 || !xe_device_uc_enabled(xe) || IS_SRIOV_VF(xe))
+
+	if (xe->wedged.mode == XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET)
+		return NULL;
+
+	if (!xe_device_uc_enabled(xe))
+		return NULL;
+
+	if (IS_SRIOV_VF(xe))
 		return NULL;
 
 	ss = &xe->devcoredump.snapshot;

drivers/gpu/drm/xe/xe_guc_submit.c

@@ -1339,8 +1339,9 @@ void xe_guc_submit_wedge(struct xe_guc *guc)
 	err = devm_add_action_or_reset(guc_to_xe(guc)->drm.dev,
 				       guc_submit_wedged_fini, guc);
 	if (err) {
-		xe_gt_err(gt, "Failed to register clean-up on wedged.mode=2; "
-			  "Although device is wedged.\n");
+		xe_gt_err(gt, "Failed to register clean-up in wedged.mode=%s; "
+			  "Although device is wedged.\n",
+			  xe_wedged_mode_to_string(XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET));
 		return;
 	}
 
@@ -1355,7 +1356,7 @@ static bool guc_submit_hint_wedged(struct xe_guc *guc)
 {
 	struct xe_device *xe = guc_to_xe(guc);
 
-	if (xe->wedged.mode != 2)
+	if (xe->wedged.mode != XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET)
 		return false;
 
 	if (xe_device_wedged(xe))

drivers/gpu/drm/xe/xe_module.c

@@ -10,6 +10,7 @@
 
 #include <drm/drm_module.h>
 
+#include "xe_device.h"
 #include "xe_drv.h"
 #include "xe_configfs.h"
 #include "xe_hw_fence.h"
@@ -29,7 +30,8 @@
 #define DEFAULT_FORCE_PROBE		CONFIG_DRM_XE_FORCE_PROBE
 #define DEFAULT_MAX_VFS			~0
 #define DEFAULT_MAX_VFS_STR		"unlimited"
-#define DEFAULT_WEDGED_MODE		1
+#define DEFAULT_WEDGED_MODE		XE_WEDGED_MODE_DEFAULT
+#define DEFAULT_WEDGED_MODE_STR		XE_WEDGED_MODE_DEFAULT_STR
 #define DEFAULT_SVM_NOTIFIER_SIZE	512
 
 struct xe_modparam xe_modparam = {
@@ -88,10 +90,10 @@ MODULE_PARM_DESC(max_vfs,
 		 "[default=" DEFAULT_MAX_VFS_STR "])");
 #endif
 
-module_param_named_unsafe(wedged_mode, xe_modparam.wedged_mode, int, 0600);
+module_param_named_unsafe(wedged_mode, xe_modparam.wedged_mode, uint, 0600);
 MODULE_PARM_DESC(wedged_mode,
-		 "Module's default policy for the wedged mode (0=never, 1=upon-critical-errors, 2=upon-any-hang "
-		 "[default=" __stringify(DEFAULT_WEDGED_MODE) "])");
+		 "Module's default policy for the wedged mode (0=never, 1=upon-critical-error, 2=upon-any-hang-no-reset "
+		 "[default=" DEFAULT_WEDGED_MODE_STR "])");
 
 static int xe_check_nomodeset(void)
 {

drivers/gpu/drm/xe/xe_module.h

@@ -21,7 +21,7 @@ struct xe_modparam {
 #ifdef CONFIG_PCI_IOV
 	unsigned int max_vfs;
 #endif
-	int wedged_mode;
+	unsigned int wedged_mode;
 	u32 svm_notifier_size;
 };