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https://github.com/torvalds/linux
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40ac971eab
xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
and uses the common helpers. Properly handle them to unbreak Xen on
ARM platforms.
Fixes: 1b65c4e5a9 ("swiotlb-xen: use xen_alloc/free_coherent_pages")
Signed-off-by: Roman Skakun <roman_skakun@epam.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
[hch: split the patch, renamed the helpers]
Signed-off-by: Christoph Hellwig <hch@lst.de>
93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Helpers for DMA ops implementations. These generally rely on the fact that
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* the allocated memory contains normal pages in the direct kernel mapping.
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*/
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#include <linux/dma-map-ops.h>
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static struct page *dma_common_vaddr_to_page(void *cpu_addr)
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{
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if (is_vmalloc_addr(cpu_addr))
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return vmalloc_to_page(cpu_addr);
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return virt_to_page(cpu_addr);
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}
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/*
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* Create scatter-list for the already allocated DMA buffer.
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*/
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int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
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void *cpu_addr, dma_addr_t dma_addr, size_t size,
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unsigned long attrs)
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{
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struct page *page = dma_common_vaddr_to_page(cpu_addr);
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int ret;
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ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
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if (!ret)
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sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
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return ret;
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}
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/*
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* Create userspace mapping for the DMA-coherent memory.
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*/
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int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
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void *cpu_addr, dma_addr_t dma_addr, size_t size,
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unsigned long attrs)
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{
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#ifdef CONFIG_MMU
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unsigned long user_count = vma_pages(vma);
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unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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unsigned long off = vma->vm_pgoff;
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struct page *page = dma_common_vaddr_to_page(cpu_addr);
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int ret = -ENXIO;
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vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
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if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
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return ret;
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if (off >= count || user_count > count - off)
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return -ENXIO;
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return remap_pfn_range(vma, vma->vm_start,
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page_to_pfn(page) + vma->vm_pgoff,
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user_count << PAGE_SHIFT, vma->vm_page_prot);
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#else
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return -ENXIO;
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#endif /* CONFIG_MMU */
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}
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struct page *dma_common_alloc_pages(struct device *dev, size_t size,
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dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
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{
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const struct dma_map_ops *ops = get_dma_ops(dev);
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struct page *page;
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page = dma_alloc_contiguous(dev, size, gfp);
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if (!page)
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page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size));
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if (!page)
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return NULL;
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*dma_handle = ops->map_page(dev, page, 0, size, dir,
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DMA_ATTR_SKIP_CPU_SYNC);
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if (*dma_handle == DMA_MAPPING_ERROR) {
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dma_free_contiguous(dev, page, size);
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return NULL;
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}
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memset(page_address(page), 0, size);
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return page;
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}
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void dma_common_free_pages(struct device *dev, size_t size, struct page *page,
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dma_addr_t dma_handle, enum dma_data_direction dir)
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{
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const struct dma_map_ops *ops = get_dma_ops(dev);
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if (ops->unmap_page)
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ops->unmap_page(dev, dma_handle, size, dir,
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DMA_ATTR_SKIP_CPU_SYNC);
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dma_free_contiguous(dev, page, size);
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}
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