arm64: Fix the DMA mmap and get_sgtable API with DMA_ATTR_FORCE_CONTIGUOUS

While honouring the DMA_ATTR_FORCE_CONTIGUOUS on arm64 (commit
44176bb38fa4: "arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to
IOMMU"), the existing uses of dma_mmap_attrs() and dma_get_sgtable()
have been broken by passing a physically contiguous vm_struct with an
invalid pages pointer through the common iommu API.

Since the coherent allocation with DMA_ATTR_FORCE_CONTIGUOUS uses CMA,
this patch simply reuses the existing swiotlb logic for mmap and
get_sgtable.

Note that the current implementation of get_sgtable (both swiotlb and
iommu) is broken if dma_declare_coherent_memory() is used since such
memory does not have a corresponding struct page. To be addressed in a
subsequent patch.

Fixes: 44176bb38fa4 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU")
Reported-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index f7b5401..c9e53de 100644 (file)
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -308,24 +308,15 @@ static void __swiotlb_sync_sg_for_device(struct device *dev,
                                       sg->length, dir);
 }
 
-static int __swiotlb_mmap(struct device *dev,
-                         struct vm_area_struct *vma,
-                         void *cpu_addr, dma_addr_t dma_addr, size_t size,
-                         unsigned long attrs)
+static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
+                             unsigned long pfn, size_t size)
 {
        int ret = -ENXIO;
        unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >>
                                        PAGE_SHIFT;
        unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-       unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT;
        unsigned long off = vma->vm_pgoff;
 
-       vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
-                                            is_device_dma_coherent(dev));
-
-       if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
-               return ret;
-
        if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
                ret = remap_pfn_range(vma, vma->vm_start,
                                      pfn + off,
@@ -336,19 +327,43 @@ static int __swiotlb_mmap(struct device *dev,
        return ret;
 }
 
-static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt,
-                                void *cpu_addr, dma_addr_t handle, size_t size,
-                                unsigned long attrs)
+static int __swiotlb_mmap(struct device *dev,
+                         struct vm_area_struct *vma,
+                         void *cpu_addr, dma_addr_t dma_addr, size_t size,
+                         unsigned long attrs)
+{
+       int ret;
+       unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT;
+
+       vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
+                                            is_device_dma_coherent(dev));
+
+       if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
+               return ret;
+
+       return __swiotlb_mmap_pfn(vma, pfn, size);
+}
+
+static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
+                                     struct page *page, size_t size)
 {
        int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
 
        if (!ret)
-               sg_set_page(sgt->sgl, phys_to_page(dma_to_phys(dev, handle)),
-                           PAGE_ALIGN(size), 0);
+               sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
 
        return ret;
 }
 
+static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt,
+                                void *cpu_addr, dma_addr_t handle, size_t size,
+                                unsigned long attrs)
+{
+       struct page *page = phys_to_page(dma_to_phys(dev, handle));
+
+       return __swiotlb_get_sgtable_page(sgt, page, size);
+}
+
 static int __swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
        if (swiotlb)
@@ -703,6 +718,15 @@ static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
        if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
                return ret;
 
+       if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+               /*
+                * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
+                * hence in the vmalloc space.
+                */
+               unsigned long pfn = vmalloc_to_pfn(cpu_addr);
+               return __swiotlb_mmap_pfn(vma, pfn, size);
+       }
+
        area = find_vm_area(cpu_addr);
        if (WARN_ON(!area || !area->pages))
                return -ENXIO;
@@ -717,6 +741,15 @@ 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 (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+               /*
+                * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
+                * hence in the vmalloc space.
+                */
+               struct page *page = vmalloc_to_page(cpu_addr);
+               return __swiotlb_get_sgtable_page(sgt, page, size);
+       }
+
        if (WARN_ON(!area || !area->pages))
                return -ENXIO;