arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable

DMA allocations that can't sleep may return non-remapped addresses, but
we do not properly handle them in the mmap and get_sgtable methods.
Resolve non-vmalloc addresses using virt_to_page to handle this corner
case.

Cc: <stable@vger.kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/mm/dma-mapping.c

@@ -249,6 +249,11 @@ static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
 		return ret;
 
+	if (!is_vmalloc_addr(cpu_addr)) {
+		unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
+		return __swiotlb_mmap_pfn(vma, pfn, size);
+	}
+
 	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
 		/*
 		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
@@ -272,6 +277,11 @@ static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	struct vm_struct *area = find_vm_area(cpu_addr);
 
+	if (!is_vmalloc_addr(cpu_addr)) {
+		struct page *page = virt_to_page(cpu_addr);
+		return __swiotlb_get_sgtable_page(sgt, page, size);
+	}
+
 	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
 		/*
 		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,