diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index e95af4ead357..4198054e703c 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -187,9 +187,329 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
 }
 EXPORT_SYMBOL_GPL(devm_create_dax_dev);
 
+/* return an unmapped area aligned to the dax region specified alignment */
+static unsigned long dax_dev_get_unmapped_area(struct file *filp,
+		unsigned long addr, unsigned long len, unsigned long pgoff,
+		unsigned long flags)
+{
+	struct dax_dev *dax_dev;
+	struct device *dev = filp ? filp->private_data : NULL;
+	unsigned long off, off_end, off_align, len_align, addr_align, align = 0;
+
+	if (!filp || addr)
+		goto out;
+
+	device_lock(dev);
+	dax_dev = dev_get_drvdata(dev);
+	if (dax_dev) {
+		struct dax_region *dax_region = dax_dev->region;
+
+		align = dax_region->align;
+	}
+	device_unlock(dev);
+
+	if (!align)
+		goto out;
+
+	off = pgoff << PAGE_SHIFT;
+	off_end = off + len;
+	off_align = round_up(off, align);
+
+	if ((off_end <= off_align) || ((off_end - off_align) < align))
+		goto out;
+
+	len_align = len + align;
+	if ((off + len_align) < off)
+		goto out;
+
+	addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
+			pgoff, flags);
+	if (!IS_ERR_VALUE(addr_align)) {
+		addr_align += (off - addr_align) & (align - 1);
+		return addr_align;
+	}
+ out:
+	return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
+}
+
+static int __match_devt(struct device *dev, const void *data)
+{
+	const dev_t *devt = data;
+
+	return dev->devt == *devt;
+}
+
+static int dax_dev_open(struct inode *inode, struct file *filp)
+{
+	struct device *dev;
+
+	dev = class_find_device(dax_class, NULL, &inode->i_rdev, __match_devt);
+	if (dev) {
+		dev_dbg(dev, "%s\n", __func__);
+		filp->private_data = dev;
+		inode->i_flags = S_DAX;
+		return 0;
+	}
+	return -ENXIO;
+}
+
+static int dax_dev_release(struct inode *inode, struct file *filp)
+{
+	struct device *dev = filp->private_data;
+
+	dev_dbg(dev, "%s\n", __func__);
+	put_device(dev);
+	return 0;
+}
+
+static struct dax_dev *to_dax_dev(struct device *dev)
+{
+	WARN_ON(dev->class != dax_class);
+	device_lock_assert(dev);
+	return dev_get_drvdata(dev);
+}
+
+static int dax_dev_check_vma(struct device *dev, struct vm_area_struct *vma,
+		const char *func)
+{
+	struct dax_dev *dax_dev = to_dax_dev(dev);
+	struct dax_region *dax_region;
+	unsigned long mask;
+
+	if (!dax_dev)
+		return -ENXIO;
+
+	/* prevent private / writable mappings from being established */
+	if ((vma->vm_flags & (VM_NORESERVE|VM_SHARED|VM_WRITE)) == VM_WRITE) {
+		dev_dbg(dev, "%s: fail, attempted private mapping\n", func);
+		return -EINVAL;
+	}
+
+	dax_region = dax_dev->region;
+	mask = dax_region->align - 1;
+	if (vma->vm_start & mask || vma->vm_end & mask) {
+		dev_dbg(dev, "%s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
+				func, vma->vm_start, vma->vm_end, mask);
+		return -EINVAL;
+	}
+
+	if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
+			&& (vma->vm_flags & VM_DONTCOPY) == 0) {
+		dev_dbg(dev, "%s: fail, dax range requires MADV_DONTFORK\n",
+				func);
+		return -EINVAL;
+	}
+
+	if (!vma_is_dax(vma)) {
+		dev_dbg(dev, "%s: fail, vma is not DAX capable\n", func);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static phys_addr_t pgoff_to_phys(struct dax_dev *dax_dev, pgoff_t pgoff,
+		unsigned long size)
+{
+	struct resource *res;
+	phys_addr_t phys;
+	int i;
+
+	for (i = 0; i < dax_dev->num_resources; i++) {
+		res = &dax_dev->res[i];
+		phys = pgoff * PAGE_SIZE + res->start;
+		if (phys >= res->start && phys <= res->end)
+			break;
+		pgoff -= PHYS_PFN(resource_size(res));
+	}
+
+	if (i < dax_dev->num_resources) {
+		res = &dax_dev->res[i];
+		if (phys + size - 1 <= res->end)
+			return phys;
+	}
+
+	return -1;
+}
+
+static int __dax_dev_fault(struct address_space *mapping, struct device *dev,
+		struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	unsigned long vaddr = (unsigned long)vmf->virtual_address;
+	struct dax_dev *dax_dev = to_dax_dev(dev);
+	struct dax_region *dax_region;
+	phys_addr_t phys;
+	pfn_t pfn;
+	int rc;
+
+	if (!dax_dev)
+		return VM_FAULT_SIGBUS;
+
+	if (dax_dev_check_vma(dev, vma, __func__))
+		return VM_FAULT_SIGBUS;
+
+	dax_region = dax_dev->region;
+	if (dax_region->align > PAGE_SIZE) {
+		dev_dbg(dev, "%s: alignment > fault size\n", __func__);
+		return VM_FAULT_SIGBUS;
+	}
+
+	phys = pgoff_to_phys(dax_dev, vmf->pgoff, PAGE_SIZE);
+	if (phys == -1) {
+		dev_dbg(dev, "%s: phys_to_pgoff(%#lx) failed\n", __func__,
+				vmf->pgoff);
+		return VM_FAULT_SIGBUS;
+	}
+
+	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
+
+	i_mmap_lock_read(mapping);
+	rc = vm_insert_mixed(vma, vaddr, pfn);
+	i_mmap_unlock_read(mapping);
+
+	if (rc == -ENOMEM)
+		return VM_FAULT_OOM;
+	if (rc < 0 && rc != -EBUSY)
+		return VM_FAULT_SIGBUS;
+
+	return VM_FAULT_NOPAGE;
+}
+
+static int dax_dev_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	int rc;
+	struct file *filp = vma->vm_file;
+	struct device *dev = filp->private_data;
+	struct address_space *mapping = filp->f_mapping;
+
+	dev_dbg(dev, "%s: %s (%#lx - %#lx)\n", __func__,
+			(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
+			vma->vm_start, vma->vm_end);
+	device_lock(dev);
+	rc = __dax_dev_fault(mapping, dev, vma, vmf);
+	device_unlock(dev);
+
+	return rc;
+}
+
+static int __dax_dev_pmd_fault(struct address_space *mapping,
+		struct device *dev, struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmd, unsigned int flags)
+{
+	struct dax_dev *dax_dev = to_dax_dev(dev);
+	unsigned long pmd_addr = addr & PMD_MASK;
+	struct dax_region *dax_region;
+	phys_addr_t phys;
+	pgoff_t pgoff;
+	pfn_t pfn;
+	int rc;
+
+	if (!dax_dev)
+		return VM_FAULT_SIGBUS;
+
+	if (dax_dev_check_vma(dev, vma, __func__))
+		return VM_FAULT_SIGBUS;
+
+	dax_region = dax_dev->region;
+	if (dax_region->align > HPAGE_SIZE) {
+		dev_dbg(dev, "%s: alignment > fault size\n", __func__);
+		return VM_FAULT_SIGBUS;
+	}
+
+	/* dax pmd mappings require pfn_t_devmap() */
+	if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
+		dev_dbg(dev, "%s: alignment > fault size\n", __func__);
+		return VM_FAULT_SIGBUS;
+	}
+
+	pgoff = linear_page_index(vma, pmd_addr);
+	phys = pgoff_to_phys(dax_dev, pgoff, PAGE_SIZE);
+	if (phys == -1) {
+		dev_dbg(dev, "%s: phys_to_pgoff(%#lx) failed\n", __func__,
+				pgoff);
+		return VM_FAULT_SIGBUS;
+	}
+
+	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
+
+	i_mmap_lock_read(mapping);
+	rc = vmf_insert_pfn_pmd(vma, addr, pmd, pfn,
+			flags & FAULT_FLAG_WRITE);
+	i_mmap_unlock_read(mapping);
+
+	return rc;
+}
+
+static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
+		pmd_t *pmd, unsigned int flags)
+{
+	int rc;
+	struct file *filp = vma->vm_file;
+	struct device *dev = filp->private_data;
+	struct address_space *mapping = filp->f_mapping;
+
+	dev_dbg(dev, "%s: %s (%#lx - %#lx)\n", __func__,
+			(flags & FAULT_FLAG_WRITE) ? "write" : "read",
+			vma->vm_start, vma->vm_end);
+	device_lock(dev);
+	rc = __dax_dev_pmd_fault(mapping, dev, vma, addr, pmd, flags);
+	device_unlock(dev);
+
+	return rc;
+}
+
+static void dax_dev_vm_open(struct vm_area_struct *vma)
+{
+	struct file *filp = vma->vm_file;
+	struct device *dev = filp->private_data;
+
+	dev_dbg(dev, "%s\n", __func__);
+	get_device(dev);
+}
+
+static void dax_dev_vm_close(struct vm_area_struct *vma)
+{
+	struct file *filp = vma->vm_file;
+	struct device *dev = filp->private_data;
+
+	dev_dbg(dev, "%s\n", __func__);
+	put_device(dev);
+}
+
+static const struct vm_operations_struct dax_dev_vm_ops = {
+	.fault = dax_dev_fault,
+	.pmd_fault = dax_dev_pmd_fault,
+	.open = dax_dev_vm_open,
+	.close = dax_dev_vm_close,
+};
+
+static int dax_dev_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct device *dev = filp->private_data;
+	int rc;
+
+	dev_dbg(dev, "%s\n", __func__);
+
+	device_lock(dev);
+	rc = dax_dev_check_vma(dev, vma, __func__);
+	device_unlock(dev);
+	if (rc)
+		return rc;
+
+	get_device(dev);
+	vma->vm_ops = &dax_dev_vm_ops;
+	vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
+	return 0;
+
+}
+
 static const struct file_operations dax_fops = {
 	.llseek = noop_llseek,
 	.owner = THIS_MODULE,
+	.open = dax_dev_open,
+	.release = dax_dev_release,
+	.get_unmapped_area = dax_dev_get_unmapped_area,
+	.mmap = dax_dev_mmap,
 };
 
 static int __init dax_init(void)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 86f9f8b82f8e..52ea012d8a80 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1013,6 +1013,7 @@ int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 	insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
 	return VM_FAULT_NOPAGE;
 }
+EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);
 
 static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
 		pmd_t *pmd)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 19d0d08b396f..b14e98129b07 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -624,6 +624,7 @@ pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
 {
 	return vma_hugecache_offset(hstate_vma(vma), vma, address);
 }
+EXPORT_SYMBOL_GPL(linear_hugepage_index);
 
 /*
  * Return the size of the pages allocated when backing a VMA. In the majority
