[PATCH 01/25] arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable

Christoph Hellwig
2019-04-30T10:51:50Z

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
arch/arm64/mm/dma-mapping.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 78c0a72f822c..674860e3e478 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/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,
--
2.20.1