Subject: [PATCH] arm64: Correct virt_addr_valid

From: [email-masked] (Laura Abbott)
Date: Mon, 16 Dec 2013 10:28:45 -0800

On 12/13/2013 3:57 AM, Catalin Marinas wrote:
>
> OK, I re-read it now.
>
>> Yes, I believe the point was that if we call virt_addr_valid on a
>> not-direct-mapped address it should return false. We still need the
>> range check on arm64 systems as well to ensure this.
>
> On arm64 we don't have highmem, so all RAM would be directly mapped (and
> linear). Is there a case on a 64-bit architecture where pfn_valid() is
> true but the memory not mapped? We don't unmap any memory which is
> pfn_valid().
>

We don't have highmem but we still have a vmalloc region. Calling 
virt_to_page on a vmalloc address will not give a valid page so 
virt_addr_valid should return false on anything in the vmalloc region.

Thanks,
Laura

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