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ARM: dma-mapping: add more sanity checks in arm_dma_mmap() 

Add some sanity checks and forbid mmaping of buffers into vma areas larger
than allocated dma buffer.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
This commit is contained in:
Marek Szyprowski 2012-07-30 09:35:26 +02:00
parent e9da6e9905
commit 50262a4bf3
1 changed files with 10 additions and 4 deletions
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14
arch/arm/mm/dma-mapping.c
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@ -611,16 +611,22 @@ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
{ {
int ret = -ENXIO; int ret = -ENXIO;
#ifdef CONFIG_MMU #ifdef CONFIG_MMU
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_pfn(dev, dma_addr); unsigned long pfn = dma_to_pfn(dev, dma_addr);
unsigned long off = vma->vm_pgoff;
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot); vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
return ret; return ret;
ret = remap_pfn_range(vma, vma->vm_start, if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
pfn + vma->vm_pgoff, ret = remap_pfn_range(vma, vma->vm_start,
vma->vm_end - vma->vm_start, pfn + off,
vma->vm_page_prot); vma->vm_end - vma->vm_start,
vma->vm_page_prot);
}
#endif /* CONFIG_MMU */ #endif /* CONFIG_MMU */
return ret; return ret;