[PATCH] Fix up mmap_kmem
vma->vm_pgoff is an pfn _offset_ relatif to the begining of the memory start. The previous code was doing at first: vma->vm_pgoff << PAGE_SHIFT which results into a wrong physical address since some platforms have a physical mem start that can be different from 0. After that the previous call __pa() on this wrong physical address, however __pa() is used to convert a _virtual_ address into a physical one. This patch rewrites this convertion. It calculates the pfn of PAGE_OFFSET which is the pfn of the mem start then it adds the vma->vm_pgoff to it. It also uses virt_to_phys() instead of __pa() since the latter shouldn't be used by drivers. Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -292,8 +292,8 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
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{
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unsigned long pfn;
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/* Turn a kernel-virtual address into a physical page frame */
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pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
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/* Turn a pfn offset into an absolute pfn */
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pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff;
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/*
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* RED-PEN: on some architectures there is more mapped memory
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