Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

3 files changed, 658 insertions, 0 deletions

diff --git a/drivers/misc/uacce/Kconfig b/drivers/misc/uacce/Kconfig
new file mode 100644
index 000000000..5e39b6083
--- /dev/null
+++ b/drivers/misc/uacce/Kconfig
@@ -0,0 +1,13 @@
+config UACCE
+	tristate "Accelerator Framework for User Land"
+	depends on IOMMU_API
+	help
+	  UACCE provides interface for the user process to access the hardware
+	  without interaction with the kernel space in data path.
+
+	  The user-space interface is described in
+	  include/uapi/misc/uacce/uacce.h
+
+	  See Documentation/misc-devices/uacce.rst for more details.
+
+	  If you don't know what to do here, say N.
diff --git a/drivers/misc/uacce/Makefile b/drivers/misc/uacce/Makefile
new file mode 100644
index 000000000..5b4374e8b
--- /dev/null
+++ b/drivers/misc/uacce/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+obj-$(CONFIG_UACCE) += uacce.o
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
new file mode 100644
index 000000000..45521d4a5
--- /dev/null
+++ b/drivers/misc/uacce/uacce.c
@@ -0,0 +1,643 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/compat.h>
+#include <linux/dma-mapping.h>
+#include <linux/iommu.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/uacce.h>
+
+static dev_t uacce_devt;
+static DEFINE_XARRAY_ALLOC(uacce_xa);
+
+static const struct class uacce_class = {
+	.name = UACCE_NAME,
+};
+
+/*
+ * If the parent driver or the device disappears, the queue state is invalid and
+ * ops are not usable anymore.
+ */
+static bool uacce_queue_is_valid(struct uacce_queue *q)
+{
+	return q->state == UACCE_Q_INIT || q->state == UACCE_Q_STARTED;
+}
+
+static int uacce_start_queue(struct uacce_queue *q)
+{
+	int ret;
+
+	if (q->state != UACCE_Q_INIT)
+		return -EINVAL;
+
+	if (q->uacce->ops->start_queue) {
+		ret = q->uacce->ops->start_queue(q);
+		if (ret < 0)
+			return ret;
+	}
+
+	q->state = UACCE_Q_STARTED;
+	return 0;
+}
+
+static int uacce_stop_queue(struct uacce_queue *q)
+{
+	struct uacce_device *uacce = q->uacce;
+
+	if (q->state != UACCE_Q_STARTED)
+		return 0;
+
+	if (uacce->ops->stop_queue)
+		uacce->ops->stop_queue(q);
+
+	q->state = UACCE_Q_INIT;
+
+	return 0;
+}
+
+static void uacce_put_queue(struct uacce_queue *q)
+{
+	struct uacce_device *uacce = q->uacce;
+
+	uacce_stop_queue(q);
+
+	if (q->state != UACCE_Q_INIT)
+		return;
+
+	if (uacce->ops->put_queue)
+		uacce->ops->put_queue(q);
+
+	q->state = UACCE_Q_ZOMBIE;
+}
+
+static long uacce_fops_unl_ioctl(struct file *filep,
+				 unsigned int cmd, unsigned long arg)
+{
+	struct uacce_queue *q = filep->private_data;
+	struct uacce_device *uacce = q->uacce;
+	long ret = -ENXIO;
+
+	/*
+	 * uacce->ops->ioctl() may take the mmap_lock when copying arg to/from
+	 * user. Avoid a circular lock dependency with uacce_fops_mmap(), which
+	 * gets called with mmap_lock held, by taking uacce->mutex instead of
+	 * q->mutex. Doing this in uacce_fops_mmap() is not possible because
+	 * uacce_fops_open() calls iommu_sva_bind_device(), which takes
+	 * mmap_lock, while holding uacce->mutex.
+	 */
+	mutex_lock(&uacce->mutex);
+	if (!uacce_queue_is_valid(q))
+		goto out_unlock;
+
+	switch (cmd) {
+	case UACCE_CMD_START_Q:
+		ret = uacce_start_queue(q);
+		break;
+	case UACCE_CMD_PUT_Q:
+		ret = uacce_stop_queue(q);
+		break;
+	default:
+		if (uacce->ops->ioctl)
+			ret = uacce->ops->ioctl(q, cmd, arg);
+		else
+			ret = -EINVAL;
+	}
+out_unlock:
+	mutex_unlock(&uacce->mutex);
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+static long uacce_fops_compat_ioctl(struct file *filep,
+				   unsigned int cmd, unsigned long arg)
+{
+	arg = (unsigned long)compat_ptr(arg);
+
+	return uacce_fops_unl_ioctl(filep, cmd, arg);
+}
+#endif
+
+static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
+{
+	u32 pasid;
+	struct iommu_sva *handle;
+
+	if (!(uacce->flags & UACCE_DEV_SVA))
+		return 0;
+
+	handle = iommu_sva_bind_device(uacce->parent, current->mm);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	pasid = iommu_sva_get_pasid(handle);
+	if (pasid == IOMMU_PASID_INVALID) {
+		iommu_sva_unbind_device(handle);
+		return -ENODEV;
+	}
+
+	q->handle = handle;
+	q->pasid = pasid;
+	return 0;
+}
+
+static void uacce_unbind_queue(struct uacce_queue *q)
+{
+	if (!q->handle)
+		return;
+	iommu_sva_unbind_device(q->handle);
+	q->handle = NULL;
+}
+
+static int uacce_fops_open(struct inode *inode, struct file *filep)
+{
+	struct uacce_device *uacce;
+	struct uacce_queue *q;
+	int ret;
+
+	uacce = xa_load(&uacce_xa, iminor(inode));
+	if (!uacce)
+		return -ENODEV;
+
+	q = kzalloc_obj(struct uacce_queue);
+	if (!q)
+		return -ENOMEM;
+
+	mutex_lock(&uacce->mutex);
+
+	if (!uacce->parent) {
+		ret = -EINVAL;
+		goto out_with_mem;
+	}
+
+	ret = uacce_bind_queue(uacce, q);
+	if (ret)
+		goto out_with_mem;
+
+	q->uacce = uacce;
+
+	if (uacce->ops->get_queue) {
+		ret = uacce->ops->get_queue(uacce, q->pasid, q);
+		if (ret < 0)
+			goto out_with_bond;
+	}
+
+	init_waitqueue_head(&q->wait);
+	filep->private_data = q;
+	q->state = UACCE_Q_INIT;
+	q->mapping = filep->f_mapping;
+	mutex_init(&q->mutex);
+	list_add(&q->list, &uacce->queues);
+	mutex_unlock(&uacce->mutex);
+
+	return 0;
+
+out_with_bond:
+	uacce_unbind_queue(q);
+out_with_mem:
+	kfree(q);
+	mutex_unlock(&uacce->mutex);
+	return ret;
+}
+
+static int uacce_fops_release(struct inode *inode, struct file *filep)
+{
+	struct uacce_queue *q = filep->private_data;
+	struct uacce_device *uacce = q->uacce;
+
+	mutex_lock(&uacce->mutex);
+	uacce_put_queue(q);
+	uacce_unbind_queue(q);
+	list_del(&q->list);
+	mutex_unlock(&uacce->mutex);
+	kfree(q);
+
+	return 0;
+}
+
+static void uacce_vma_close(struct vm_area_struct *vma)
+{
+	struct uacce_queue *q = vma->vm_private_data;
+
+	if (vma->vm_pgoff < UACCE_MAX_REGION) {
+		struct uacce_qfile_region *qfr = q->qfrs[vma->vm_pgoff];
+
+		mutex_lock(&q->mutex);
+		q->qfrs[vma->vm_pgoff] = NULL;
+		mutex_unlock(&q->mutex);
+		kfree(qfr);
+	}
+}
+
+static int uacce_vma_mremap(struct vm_area_struct *area)
+{
+	return -EPERM;
+}
+
+static const struct vm_operations_struct uacce_vm_ops = {
+	.close = uacce_vma_close,
+	.mremap = uacce_vma_mremap,
+};
+
+static int uacce_fops_mmap(struct file *filep, struct vm_area_struct *vma)
+{
+	struct uacce_queue *q = filep->private_data;
+	struct uacce_device *uacce = q->uacce;
+	struct uacce_qfile_region *qfr;
+	enum uacce_qfrt type = UACCE_MAX_REGION;
+	int ret = 0;
+
+	if (vma->vm_pgoff < UACCE_MAX_REGION)
+		type = vma->vm_pgoff;
+	else
+		return -EINVAL;
+
+	qfr = kzalloc_obj(*qfr);
+	if (!qfr)
+		return -ENOMEM;
+
+	vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_WIPEONFORK);
+	vma->vm_ops = &uacce_vm_ops;
+	vma->vm_private_data = q;
+	qfr->type = type;
+
+	mutex_lock(&q->mutex);
+	if (!uacce_queue_is_valid(q)) {
+		ret = -ENXIO;
+		goto out_with_lock;
+	}
+
+	if (q->qfrs[type]) {
+		ret = -EEXIST;
+		goto out_with_lock;
+	}
+
+	switch (type) {
+	case UACCE_QFRT_MMIO:
+	case UACCE_QFRT_DUS:
+		if (!uacce->ops->mmap) {
+			ret = -EINVAL;
+			goto out_with_lock;
+		}
+
+		ret = uacce->ops->mmap(q, vma, qfr);
+		if (ret)
+			goto out_with_lock;
+		break;
+
+	default:
+		ret = -EINVAL;
+		goto out_with_lock;
+	}
+
+	q->qfrs[type] = qfr;
+	mutex_unlock(&q->mutex);
+
+	return ret;
+
+out_with_lock:
+	mutex_unlock(&q->mutex);
+	kfree(qfr);
+	return ret;
+}
+
+static __poll_t uacce_fops_poll(struct file *file, poll_table *wait)
+{
+	struct uacce_queue *q = file->private_data;
+	struct uacce_device *uacce = q->uacce;
+	__poll_t ret = 0;
+
+	mutex_lock(&q->mutex);
+	if (!uacce_queue_is_valid(q))
+		goto out_unlock;
+
+	poll_wait(file, &q->wait, wait);
+
+	if (uacce->ops->is_q_updated && uacce->ops->is_q_updated(q))
+		ret = EPOLLIN | EPOLLRDNORM;
+
+out_unlock:
+	mutex_unlock(&q->mutex);
+	return ret;
+}
+
+static const struct file_operations uacce_fops = {
+	.owner		= THIS_MODULE,
+	.open		= uacce_fops_open,
+	.release	= uacce_fops_release,
+	.unlocked_ioctl	= uacce_fops_unl_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= uacce_fops_compat_ioctl,
+#endif
+	.mmap		= uacce_fops_mmap,
+	.poll		= uacce_fops_poll,
+};
+
+#define to_uacce_device(dev) container_of(dev, struct uacce_device, dev)
+
+static ssize_t api_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%s\n", uacce->api_ver);
+}
+
+static ssize_t flags_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%u\n", uacce->flags);
+}
+
+static ssize_t available_instances_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	if (!uacce->ops->get_available_instances)
+		return -ENODEV;
+
+	return sysfs_emit(buf, "%d\n",
+		       uacce->ops->get_available_instances(uacce));
+}
+
+static ssize_t algorithms_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%s\n", uacce->algs);
+}
+
+static ssize_t region_mmio_size_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%lu\n",
+		       uacce->qf_pg_num[UACCE_QFRT_MMIO] << PAGE_SHIFT);
+}
+
+static ssize_t region_dus_size_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%lu\n",
+		       uacce->qf_pg_num[UACCE_QFRT_DUS] << PAGE_SHIFT);
+}
+
+static ssize_t isolate_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%d\n", uacce->ops->get_isolate_state(uacce));
+}
+
+static ssize_t isolate_strategy_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+	u32 val;
+
+	if (!uacce->ops->isolate_err_threshold_read)
+		return -ENOENT;
+
+	val = uacce->ops->isolate_err_threshold_read(uacce);
+
+	return sysfs_emit(buf, "%u\n", val);
+}
+
+static ssize_t isolate_strategy_store(struct device *dev, struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+	unsigned long val;
+	int ret;
+
+	if (!uacce->ops->isolate_err_threshold_write)
+		return -ENOENT;
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val > UACCE_MAX_ERR_THRESHOLD)
+		return -EINVAL;
+
+	ret = uacce->ops->isolate_err_threshold_write(uacce, val);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR_RO(api);
+static DEVICE_ATTR_RO(flags);
+static DEVICE_ATTR_RO(available_instances);
+static DEVICE_ATTR_RO(algorithms);
+static DEVICE_ATTR_RO(region_mmio_size);
+static DEVICE_ATTR_RO(region_dus_size);
+static DEVICE_ATTR_RO(isolate);
+static DEVICE_ATTR_RW(isolate_strategy);
+
+static struct attribute *uacce_dev_attrs[] = {
+	&dev_attr_api.attr,
+	&dev_attr_flags.attr,
+	&dev_attr_available_instances.attr,
+	&dev_attr_algorithms.attr,
+	&dev_attr_region_mmio_size.attr,
+	&dev_attr_region_dus_size.attr,
+	&dev_attr_isolate.attr,
+	&dev_attr_isolate_strategy.attr,
+	NULL,
+};
+
+static umode_t uacce_dev_is_visible(struct kobject *kobj,
+				    struct attribute *attr, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	if (((attr == &dev_attr_region_mmio_size.attr) &&
+	    (!uacce->qf_pg_num[UACCE_QFRT_MMIO])) ||
+	    ((attr == &dev_attr_region_dus_size.attr) &&
+	    (!uacce->qf_pg_num[UACCE_QFRT_DUS])))
+		return 0;
+
+	if (attr == &dev_attr_isolate_strategy.attr &&
+	    (!uacce->ops->isolate_err_threshold_read &&
+	     !uacce->ops->isolate_err_threshold_write))
+		return 0;
+
+	if (attr == &dev_attr_isolate.attr && !uacce->ops->get_isolate_state)
+		return 0;
+
+	return attr->mode;
+}
+
+static struct attribute_group uacce_dev_group = {
+	.is_visible	= uacce_dev_is_visible,
+	.attrs		= uacce_dev_attrs,
+};
+
+__ATTRIBUTE_GROUPS(uacce_dev);
+
+static void uacce_release(struct device *dev)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	kfree(uacce);
+}
+
+/**
+ * uacce_alloc() - alloc an accelerator
+ * @parent: pointer of uacce parent device
+ * @interface: pointer of uacce_interface for register
+ *
+ * Returns uacce pointer if success and ERR_PTR if not
+ * Need check returned negotiated uacce->flags
+ */
+struct uacce_device *uacce_alloc(struct device *parent,
+				 struct uacce_interface *interface)
+{
+	unsigned int flags = interface->flags;
+	struct uacce_device *uacce;
+	int ret;
+
+	uacce = kzalloc_obj(struct uacce_device);
+	if (!uacce)
+		return ERR_PTR(-ENOMEM);
+
+	uacce->parent = parent;
+	uacce->flags = flags;
+	uacce->ops = interface->ops;
+
+	ret = xa_alloc(&uacce_xa, &uacce->dev_id, uacce, xa_limit_32b,
+		       GFP_KERNEL);
+	if (ret < 0)
+		goto err_with_uacce;
+
+	INIT_LIST_HEAD(&uacce->queues);
+	mutex_init(&uacce->mutex);
+	device_initialize(&uacce->dev);
+	uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id);
+	uacce->dev.class = &uacce_class;
+	uacce->dev.groups = uacce_dev_groups;
+	uacce->dev.parent = uacce->parent;
+	uacce->dev.release = uacce_release;
+	dev_set_name(&uacce->dev, "%s-%d", interface->name, uacce->dev_id);
+
+	return uacce;
+
+err_with_uacce:
+	kfree(uacce);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(uacce_alloc);
+
+/**
+ * uacce_register() - add the accelerator to cdev and export to user space
+ * @uacce: The initialized uacce device
+ *
+ * Return 0 if register succeeded, or an error.
+ */
+int uacce_register(struct uacce_device *uacce)
+{
+	int ret;
+
+	if (!uacce)
+		return -ENODEV;
+
+	uacce->cdev = cdev_alloc();
+	if (!uacce->cdev)
+		return -ENOMEM;
+
+	uacce->cdev->ops = &uacce_fops;
+	uacce->cdev->owner = THIS_MODULE;
+
+	ret = cdev_device_add(uacce->cdev, &uacce->dev);
+	if (ret)
+		uacce->cdev = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(uacce_register);
+
+/**
+ * uacce_remove() - remove the accelerator
+ * @uacce: the accelerator to remove
+ */
+void uacce_remove(struct uacce_device *uacce)
+{
+	struct uacce_queue *q, *next_q;
+
+	if (!uacce)
+		return;
+
+	/*
+	 * uacce_fops_open() may be running concurrently, even after we remove
+	 * the cdev. Holding uacce->mutex ensures that open() does not obtain a
+	 * removed uacce device.
+	 */
+	mutex_lock(&uacce->mutex);
+	/* ensure no open queue remains */
+	list_for_each_entry_safe(q, next_q, &uacce->queues, list) {
+		/*
+		 * Taking q->mutex ensures that fops do not use the defunct
+		 * uacce->ops after the queue is disabled.
+		 */
+		mutex_lock(&q->mutex);
+		uacce_put_queue(q);
+		mutex_unlock(&q->mutex);
+		uacce_unbind_queue(q);
+
+		/*
+		 * unmap remaining mapping from user space, preventing user still
+		 * access the mmaped area while parent device is already removed
+		 */
+		unmap_mapping_range(q->mapping, 0, 0, 1);
+	}
+
+	if (uacce->cdev)
+		cdev_device_del(uacce->cdev, &uacce->dev);
+	xa_erase(&uacce_xa, uacce->dev_id);
+	/*
+	 * uacce exists as long as there are open fds, but ops will be freed
+	 * now. Ensure that bugs cause NULL deref rather than use-after-free.
+	 */
+	uacce->ops = NULL;
+	uacce->parent = NULL;
+	mutex_unlock(&uacce->mutex);
+	put_device(&uacce->dev);
+}
+EXPORT_SYMBOL_GPL(uacce_remove);
+
+static int __init uacce_init(void)
+{
+	int ret;
+
+	ret = class_register(&uacce_class);
+	if (ret)
+		return ret;
+
+	ret = alloc_chrdev_region(&uacce_devt, 0, MINORMASK, UACCE_NAME);
+	if (ret)
+		class_unregister(&uacce_class);
+
+	return ret;
+}
+
+static __exit void uacce_exit(void)
+{
+	unregister_chrdev_region(uacce_devt, MINORMASK);
+	class_unregister(&uacce_class);
+}
+
+subsys_initcall(uacce_init);
+module_exit(uacce_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("HiSilicon Tech. Co., Ltd.");
+MODULE_DESCRIPTION("Accelerator interface for Userland applications");