1 files changed, 162 insertions, 105 deletions

diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index 281c54003edc..42e7d2a2a90c 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -7,45 +7,43 @@
 #include <linux/slab.h>
 #include <linux/uacce.h>
 
-static struct class *uacce_class;
 static dev_t uacce_devt;
-static DEFINE_MUTEX(uacce_mutex);
 static DEFINE_XARRAY_ALLOC(uacce_xa);
 
-static int uacce_start_queue(struct uacce_queue *q)
+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)
 {
-	int ret = 0;
+	return q->state == UACCE_Q_INIT || q->state == UACCE_Q_STARTED;
+}
 
-	mutex_lock(&uacce_mutex);
+static int uacce_start_queue(struct uacce_queue *q)
+{
+	int ret;
 
-	if (q->state != UACCE_Q_INIT) {
-		ret = -EINVAL;
-		goto out_with_lock;
-	}
+	if (q->state != UACCE_Q_INIT)
+		return -EINVAL;
 
 	if (q->uacce->ops->start_queue) {
 		ret = q->uacce->ops->start_queue(q);
 		if (ret < 0)
-			goto out_with_lock;
+			return ret;
 	}
 
 	q->state = UACCE_Q_STARTED;
-
-out_with_lock:
-	mutex_unlock(&uacce_mutex);
-
-	return ret;
+	return 0;
 }
 
 static int uacce_put_queue(struct uacce_queue *q)
 {
 	struct uacce_device *uacce = q->uacce;
 
-	mutex_lock(&uacce_mutex);
-
-	if (q->state == UACCE_Q_ZOMBIE)
-		goto out;
-
 	if ((q->state == UACCE_Q_STARTED) && uacce->ops->stop_queue)
 		uacce->ops->stop_queue(q);
 
@@ -54,8 +52,6 @@ static int uacce_put_queue(struct uacce_queue *q)
 		uacce->ops->put_queue(q);
 
 	q->state = UACCE_Q_ZOMBIE;
-out:
-	mutex_unlock(&uacce_mutex);
 
 	return 0;
 }
@@ -65,20 +61,36 @@ static long uacce_fops_unl_ioctl(struct file *filep,
 {
 	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:
-		return uacce_start_queue(q);
-
+		ret = uacce_start_queue(q);
+		break;
 	case UACCE_CMD_PUT_Q:
-		return uacce_put_queue(q);
-
+		ret = uacce_put_queue(q);
+		break;
 	default:
-		if (!uacce->ops->ioctl)
-			return -EINVAL;
-
-		return uacce->ops->ioctl(q, cmd, arg);
+		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
@@ -99,7 +111,7 @@ static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
 	if (!(uacce->flags & UACCE_DEV_SVA))
 		return 0;
 
-	handle = iommu_sva_bind_device(uacce->parent, current->mm, NULL);
+	handle = iommu_sva_bind_device(uacce->parent, current->mm);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
@@ -136,6 +148,13 @@ static int uacce_fops_open(struct inode *inode, struct file *filep)
 	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;
@@ -150,12 +169,11 @@ static int uacce_fops_open(struct inode *inode, struct file *filep)
 
 	init_waitqueue_head(&q->wait);
 	filep->private_data = q;
-	uacce->inode = inode;
 	q->state = UACCE_Q_INIT;
-
-	mutex_lock(&uacce->queues_lock);
+	q->mapping = filep->f_mapping;
+	mutex_init(&q->mutex);
 	list_add(&q->list, &uacce->queues);
-	mutex_unlock(&uacce->queues_lock);
+	mutex_unlock(&uacce->mutex);
 
 	return 0;
 
@@ -163,18 +181,20 @@ 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(&q->uacce->queues_lock);
-	list_del(&q->list);
-	mutex_unlock(&q->uacce->queues_lock);
+	mutex_lock(&uacce->mutex);
 	uacce_put_queue(q);
 	uacce_unbind_queue(q);
+	list_del(&q->list);
+	mutex_unlock(&uacce->mutex);
 	kfree(q);
 
 	return 0;
@@ -183,12 +203,15 @@ static int uacce_fops_release(struct inode *inode, struct file *filep)
 static void uacce_vma_close(struct vm_area_struct *vma)
 {
 	struct uacce_queue *q = vma->vm_private_data;
-	struct uacce_qfile_region *qfr = NULL;
 
-	if (vma->vm_pgoff < UACCE_MAX_REGION)
-		qfr = q->qfrs[vma->vm_pgoff];
+	if (vma->vm_pgoff < UACCE_MAX_REGION) {
+		struct uacce_qfile_region *qfr = q->qfrs[vma->vm_pgoff];
 
-	kfree(qfr);
+		mutex_lock(&q->mutex);
+		q->qfrs[vma->vm_pgoff] = NULL;
+		mutex_unlock(&q->mutex);
+		kfree(qfr);
+	}
 }
 
 static const struct vm_operations_struct uacce_vm_ops = {
@@ -212,15 +235,14 @@ static int uacce_fops_mmap(struct file *filep, struct vm_area_struct *vma)
 	if (!qfr)
 		return -ENOMEM;
 
-	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_WIPEONFORK;
+	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(&uacce_mutex);
-
-	if (q->state != UACCE_Q_INIT && q->state != UACCE_Q_STARTED) {
-		ret = -EINVAL;
+	mutex_lock(&q->mutex);
+	if (!uacce_queue_is_valid(q)) {
+		ret = -ENXIO;
 		goto out_with_lock;
 	}
 
@@ -248,12 +270,12 @@ static int uacce_fops_mmap(struct file *filep, struct vm_area_struct *vma)
 	}
 
 	q->qfrs[type] = qfr;
-	mutex_unlock(&uacce_mutex);
+	mutex_unlock(&q->mutex);
 
 	return ret;
 
 out_with_lock:
-	mutex_unlock(&uacce_mutex);
+	mutex_unlock(&q->mutex);
 	kfree(qfr);
 	return ret;
 }
@@ -262,12 +284,20 @@ 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))
-		return EPOLLIN | EPOLLRDNORM;
+		ret = EPOLLIN | EPOLLRDNORM;
 
-	return 0;
+out_unlock:
+	mutex_unlock(&q->mutex);
+	return ret;
 }
 
 static const struct file_operations uacce_fops = {
@@ -339,12 +369,52 @@ static ssize_t region_dus_size_show(struct device *dev,
 		       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;
+
+	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 (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,
@@ -353,6 +423,8 @@ static struct attribute *uacce_dev_attrs[] = {
 	&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,
 };
 
@@ -368,6 +440,14 @@ static umode_t uacce_dev_is_visible(struct kobject *kobj,
 	    (!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;
 }
 
@@ -385,40 +465,6 @@ static void uacce_release(struct device *dev)
 	kfree(uacce);
 }
 
-static unsigned int uacce_enable_sva(struct device *parent, unsigned int flags)
-{
-	int ret;
-
-	if (!(flags & UACCE_DEV_SVA))
-		return flags;
-
-	flags &= ~UACCE_DEV_SVA;
-
-	ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_IOPF);
-	if (ret) {
-		dev_err(parent, "failed to enable IOPF feature! ret = %pe\n", ERR_PTR(ret));
-		return flags;
-	}
-
-	ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA);
-	if (ret) {
-		dev_err(parent, "failed to enable SVA feature! ret = %pe\n", ERR_PTR(ret));
-		iommu_dev_disable_feature(parent, IOMMU_DEV_FEAT_IOPF);
-		return flags;
-	}
-
-	return flags | UACCE_DEV_SVA;
-}
-
-static void uacce_disable_sva(struct uacce_device *uacce)
-{
-	if (!(uacce->flags & UACCE_DEV_SVA))
-		return;
-
-	iommu_dev_disable_feature(uacce->parent, IOMMU_DEV_FEAT_SVA);
-	iommu_dev_disable_feature(uacce->parent, IOMMU_DEV_FEAT_IOPF);
-}
-
 /**
  * uacce_alloc() - alloc an accelerator
  * @parent: pointer of uacce parent device
@@ -438,8 +484,6 @@ struct uacce_device *uacce_alloc(struct device *parent,
 	if (!uacce)
 		return ERR_PTR(-ENOMEM);
 
-	flags = uacce_enable_sva(parent, flags);
-
 	uacce->parent = parent;
 	uacce->flags = flags;
 	uacce->ops = interface->ops;
@@ -450,10 +494,10 @@ struct uacce_device *uacce_alloc(struct device *parent,
 		goto err_with_uacce;
 
 	INIT_LIST_HEAD(&uacce->queues);
-	mutex_init(&uacce->queues_lock);
+	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.class = &uacce_class;
 	uacce->dev.groups = uacce_dev_groups;
 	uacce->dev.parent = uacce->parent;
 	uacce->dev.release = uacce_release;
@@ -462,7 +506,6 @@ struct uacce_device *uacce_alloc(struct device *parent,
 	return uacce;
 
 err_with_uacce:
-	uacce_disable_sva(uacce);
 	kfree(uacce);
 	return ERR_PTR(ret);
 }
@@ -500,27 +543,41 @@ void uacce_remove(struct uacce_device *uacce)
 
 	if (!uacce)
 		return;
+
 	/*
-	 * unmap remaining mapping from user space, preventing user still
-	 * access the mmaped area while parent device is already removed
+	 * 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.
 	 */
-	if (uacce->inode)
-		unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1);
-
+	mutex_lock(&uacce->mutex);
 	/* ensure no open queue remains */
-	mutex_lock(&uacce->queues_lock);
 	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);
-	}
-	mutex_unlock(&uacce->queues_lock);
 
-	/* disable sva now since no opened queues */
-	uacce_disable_sva(uacce);
+		/*
+		 * 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);
@@ -529,13 +586,13 @@ static int __init uacce_init(void)
 {
 	int ret;
 
-	uacce_class = class_create(THIS_MODULE, UACCE_NAME);
-	if (IS_ERR(uacce_class))
-		return PTR_ERR(uacce_class);
+	ret = class_register(&uacce_class);
+	if (ret)
+		return ret;
 
 	ret = alloc_chrdev_region(&uacce_devt, 0, MINORMASK, UACCE_NAME);
 	if (ret)
-		class_destroy(uacce_class);
+		class_unregister(&uacce_class);
 
 	return ret;
 }
@@ -543,7 +600,7 @@ static int __init uacce_init(void)
 static __exit void uacce_exit(void)
 {
 	unregister_chrdev_region(uacce_devt, MINORMASK);
-	class_destroy(uacce_class);
+	class_unregister(&uacce_class);
 }
 
 subsys_initcall(uacce_init);