Message-Id: <20251215115457.2137485-6-lukas.zapolskas@arm.com>
Date: Mon, 15 Dec 2025 11:54:57 +0000
From: Lukas Zapolskas <lukas.zapolskas@....com>
To: Boris Brezillon <boris.brezillon@...labora.com>,
	Liviu Dudau <liviu.dudau@....com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>
Cc: nd@....com,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	Lukas Zapolskas <lukas.zapolskas@....com>,
	Ketil Johnsen <ketil.johnsen@....com>
Subject: [PATCH v1 5/5] drm/panthor: Use GROUP_GET_STATE to provide group and queue errors

GROUP_GET_STATE now can be called two times: the first time to
enumerate the faults that occurred on the associated queues, and
the second time to copy out any fault information. The
necessary infrastructure to copy out drm_panthor_obj_array's
is pulled in from
https://lore.kernel.org/dri-devel/20240828172605.19176-7-mihail.atanassov@arm.com/

Signed-off-by: Lukas Zapolskas <lukas.zapolskas@....com>
Co-developed-by: Ketil Johnsen <ketil.johnsen@....com>
Signed-off-by: Ketil Johnsen <ketil.johnsen@....com>
---
 drivers/gpu/drm/panthor/panthor_drv.c   | 85 ++++++++++++++++++++++-
 drivers/gpu/drm/panthor/panthor_sched.c | 92 +++++++++++++++++++++++--
 drivers/gpu/drm/panthor/panthor_sched.h |  4 +-
 include/uapi/drm/panthor_drm.h          | 24 +++++++
 4 files changed, 195 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 98d4e8d867ed..bdcaf85b98cd 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -75,6 +75,55 @@ panthor_set_uobj(u64 usr_ptr, u32 usr_size, u32 min_size, u32 kern_size, const v
 	return 0;
 }
 
+/**
+ * panthor_set_uobj_array() - Copy a kernel object array into a user object array.
+ * @out: The object array to copy to.
+ * @min_stride: Minimum array stride.
+ * @obj_size: Kernel object size.
+ * @in: Kernel object array to copy from.
+ *
+ * Helper automating kernel -> user object copies.
+ *
+ * Don't use this function directly, use PANTHOR_UOBJ_SET_ARRAY() instead.
+ *
+ * Return: 0 on success, a negative error code otherwise.
+ */
+static int
+panthor_set_uobj_array(const struct drm_panthor_obj_array *out, u32 min_stride, u32 obj_size,
+		       const void *in)
+{
+	if (out->stride < min_stride)
+		return -EINVAL;
+
+	if (!out->count)
+		return 0;
+
+	if (obj_size == out->stride) {
+		if (copy_to_user(u64_to_user_ptr(out->array), in,
+				 (unsigned long)obj_size * out->count))
+			return -EFAULT;
+	} else {
+		u32 cpy_elem_size = min_t(u32, out->stride, obj_size);
+		void __user *out_ptr = u64_to_user_ptr(out->array);
+		const void *in_ptr = in;
+
+		for (u32 i = 0; i < out->count; i++) {
+			if (copy_to_user(out_ptr, in_ptr, cpy_elem_size))
+				return -EFAULT;
+
+			if (out->stride > obj_size &&
+			    clear_user(out_ptr + cpy_elem_size, out->stride - obj_size)) {
+				return -EFAULT;
+			}
+
+			out_ptr += out->stride;
+			in_ptr += obj_size;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * panthor_get_uobj_array() - Copy a user object array into a kernel accessible object array.
  * @in: The object array to copy.
@@ -178,7 +227,8 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs), \
-		 PANTHOR_UOBJ_DECL(struct drm_panthor_bo_sync_op, size))
+		 PANTHOR_UOBJ_DECL(struct drm_panthor_bo_sync_op, size), \
+		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_event, exception_data))
 
 /**
  * PANTHOR_UOBJ_SET() - Copy a kernel object to a user object.
@@ -193,6 +243,20 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
 			 PANTHOR_UOBJ_MIN_SIZE(_src_obj), \
 			 sizeof(_src_obj), &(_src_obj))
 
+/**
+ * PANTHOR_UOBJ_SET_ARRAY() - Copies from _src_array to @_dest_drm_panthor_obj_array.array.
+ * @_dest_drm_panthor_obj_array: The &struct drm_panthor_obj_array containing a __u64 raw
+ * pointer to the destination C array in user space and the size of each array
+ * element in user space (the 'stride').
+ * @_src_array: The source C array object in kernel space.
+ *
+ * Return: Error code. See panthor_set_uobj_array().
+ */
+#define PANTHOR_UOBJ_SET_ARRAY(_dest_drm_panthor_obj_array, _src_array) \
+	panthor_set_uobj_array(_dest_drm_panthor_obj_array, \
+			       PANTHOR_UOBJ_MIN_SIZE((_src_array)[0]), \
+			       sizeof((_src_array)[0]), _src_array)
+
 /**
  * PANTHOR_UOBJ_GET_ARRAY() - Copy a user object array to a kernel accessible
  * object array.
@@ -1128,9 +1192,23 @@ static int panthor_ioctl_group_get_state(struct drm_device *ddev, void *data,
 					 struct drm_file *file)
 {
 	struct panthor_file *pfile = file->driver_priv;
+	struct drm_panthor_queue_event *__free(kvfree) events = NULL;
 	struct drm_panthor_group_get_state *args = data;
+	int ret;
 
-	return panthor_group_get_state(pfile, args);
+	/* First call enumerates the faults. */
+	if (!args->faults.count && !args->faults.array)
+		return panthor_group_get_state(pfile, args, NULL, 0);
+
+	ret = PANTHOR_UOBJ_GET_ARRAY(events, &args->faults);
+	if (ret)
+		return ret;
+
+	ret = panthor_group_get_state(pfile, args, events, args->faults.count);
+	if (!ret)
+		ret = PANTHOR_UOBJ_SET_ARRAY(&args->faults, events);
+
+	return ret;
 }
 
 static int panthor_ioctl_tiler_heap_create(struct drm_device *ddev, void *data,
@@ -1678,6 +1756,7 @@ static void panthor_debugfs_init(struct drm_minor *minor)
  *       - adds DRM_IOCTL_PANTHOR_BO_SYNC ioctl
  *       - adds DRM_IOCTL_PANTHOR_BO_QUERY_INFO ioctl
  *       - adds drm_panthor_gpu_info::selected_coherency
+ * - 1.8 - extends GROUP_GET_STATE to propagate fault and fatal event metadata
  */
 static const struct drm_driver panthor_drm_driver = {
 	.driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ |
@@ -1691,7 +1770,7 @@ static const struct drm_driver panthor_drm_driver = {
 	.name = "panthor",
 	.desc = "Panthor DRM driver",
 	.major = 1,
-	.minor = 7,
+	.minor = 8,
 
 	.gem_create_object = panthor_gem_create_object,
 	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index 9ea0d2b27114..f58d9a21dec4 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -3872,21 +3872,86 @@ static struct panthor_group *group_from_handle(struct panthor_group_pool *pool,
 	return group;
 }
 
+static int panthor_group_count_faults(struct panthor_scheduler *sched, struct panthor_group *group)
+{
+	int count = 0;
+	unsigned long queue_events = group->fault_queues | group->fatal_queues;
+
+	lockdep_assert(&sched->lock);
+
+	for (size_t i = 0; i < group->queue_count; i++) {
+		struct panthor_queue *queue;
+		struct panthor_queue_event *evnt;
+
+		if (!test_bit(i, &queue_events))
+			continue;
+
+		queue = group->queues[i];
+		if (!queue)
+			continue;
+
+		list_for_each_entry(evnt, &queue->events, link)
+			count++;
+	}
+
+	return count;
+}
+
+static void panthor_group_get_faults(struct panthor_scheduler *sched, struct panthor_group *group,
+				     struct drm_panthor_queue_event *events, u32 count)
+{
+	int nr_events = 0;
+	unsigned long queue_events = group->fault_queues | group->fatal_queues;
+
+	lockdep_assert(&sched->lock);
+
+	for (u32 i = 0; i < group->queue_count; i++) {
+		struct panthor_queue *queue;
+		struct panthor_queue_event *evnt, *tmp;
+
+		if (!test_bit(i, &queue_events))
+			continue;
+
+		queue = group->queues[i];
+
+		if (!queue)
+			continue;
+
+		list_for_each_entry_safe(evnt, tmp, &queue->events, link) {
+			if (nr_events >= count)
+				return;
+
+			events[nr_events++] = evnt->event;
+			list_del(&evnt->link);
+			kfree(evnt);
+		}
+
+		/* In case of additional faults being generated between invocations
+		 * of group_get state, there may not be enough space to drain
+		 * events to the user provided buffer. In those cases, the queue
+		 * should remain listed as faulted.
+		 */
+		if ((group->fault_queues & BIT(i)) && list_empty(&queue->events))
+			group->fault_queues &= ~BIT(i);
+	}
+}
+
 int panthor_group_get_state(struct panthor_file *pfile,
-			    struct drm_panthor_group_get_state *get_state)
+			    struct drm_panthor_group_get_state *get_state,
+			    struct drm_panthor_queue_event *events, u32 count)
 {
 	struct panthor_group_pool *gpool = pfile->groups;
 	struct panthor_device *ptdev = pfile->ptdev;
 	struct panthor_scheduler *sched = ptdev->scheduler;
-	struct panthor_group *group;
+	struct panthor_group *group = NULL;
+	u32 fault_count;
 
 	group = group_from_handle(gpool, get_state->group_handle);
 	if (!group)
 		return -EINVAL;
 
-	memset(get_state, 0, sizeof(*get_state));
+	guard(mutex)(&sched->lock);
 
-	mutex_lock(&sched->lock);
 	if (group->timedout)
 		get_state->state |= DRM_PANTHOR_GROUP_STATE_TIMEDOUT;
 	if (group->fatal_queues) {
@@ -3898,10 +3963,25 @@ int panthor_group_get_state(struct panthor_file *pfile,
 	if (group->fault_queues) {
 		get_state->state |= DRM_PANTHOR_GROUP_STATE_QUEUE_FAULT;
 		get_state->fault_queues = group->fault_queues;
-		group->fault_queues = 0;
 	}
-	mutex_unlock(&sched->lock);
 
+	get_state->exception_type = group->fault.exception_type;
+	get_state->access_type = group->fault.access_type;
+	get_state->source_id = group->fault.source_id;
+	get_state->valid_address = group->fault.valid_address;
+	get_state->address = group->fault.address;
+
+	fault_count = panthor_group_count_faults(sched, group);
+
+	if (!count && !events) {
+		get_state->faults.count = fault_count;
+		get_state->faults.stride = sizeof(struct drm_panthor_queue_event);
+		goto exit;
+	}
+
+	panthor_group_get_faults(sched, group, events, min(get_state->faults.count, count));
+
+exit:
 	group_put(group);
 	return 0;
 }
diff --git a/drivers/gpu/drm/panthor/panthor_sched.h b/drivers/gpu/drm/panthor/panthor_sched.h
index f4a475aa34c0..d75870a6d836 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.h
+++ b/drivers/gpu/drm/panthor/panthor_sched.h
@@ -14,6 +14,7 @@ struct drm_panthor_group_create;
 struct drm_panthor_queue_create;
 struct drm_panthor_group_get_state;
 struct drm_panthor_queue_submit;
+struct drm_panthor_queue_event;
 struct panthor_device;
 struct panthor_file;
 struct panthor_group_pool;
@@ -25,7 +26,8 @@ int panthor_group_create(struct panthor_file *pfile,
 			 u64 drm_client_id);
 int panthor_group_destroy(struct panthor_file *pfile, u32 group_handle);
 int panthor_group_get_state(struct panthor_file *pfile,
-			    struct drm_panthor_group_get_state *get_state);
+			    struct drm_panthor_group_get_state *get_state,
+			    struct drm_panthor_queue_event *events, u32 count);
 
 struct drm_sched_job *
 panthor_job_create(struct panthor_file *pfile,
diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
index 083a02418d28..931c8371b1b6 100644
--- a/include/uapi/drm/panthor_drm.h
+++ b/include/uapi/drm/panthor_drm.h
@@ -1012,6 +1012,30 @@ struct drm_panthor_group_get_state {
 
 	/** @fatal_queues: Bitmask of queues that faced fatal faults. */
 	__u32 fault_queues;
+
+	/** @exception_type: The type of exception that caused the fault. */
+	__u32 exception_type;
+
+	/** @access_type: The direction of the data transfer that caused the fault., if known. */
+	__u32 access_type;
+
+	/** @source_id: ID supplying further data about the source of the fault. */
+	__u32 source_id;
+
+	/**
+	 * @valid_address: Whether the address is valid or not. Some faults may not come with
+	 * a valid GPU VA.
+	 */
+	__u8 valid_address;
+
+	/** @pad0: MBZ. */
+	__u8 pad0[3];
+
+	/** @address: GPU VA of the faulting access, if present. */
+	__u64 address;
+
+	/** @faults: Array of faults passed back to the user. */
+	struct drm_panthor_obj_array faults;
 };
 
 /**
-- 
2.33.0.dirty

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