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    SubjectRe: clean way to support >32bit addr on 32bit CPU
    William Lee Irwin III wrote:
    > On Mon, Jan 10, 2005 at 05:30:25PM -0800, Linus Torvalds wrote:
    >>I don't think ioaddr_t needs to match resources. None of the IO accessor
    >>functions take "u64"s anyway - and aren't likely to do so in the future
    >>either - so "unsigned long" should be good enough.
    >>Having u64 for resource handling is mainly an issue for RAM and
    >>memory-mapped IO (right now the 32-bit limit means that we throw away
    >>information about stuff above the 4GB mark from the e820 interfaces on
    >>x86, for example - that _happens_ to work because we never see anything
    >>but RAM there anyway, but it means that /proc/iomem doesn't show all of
    >>the system RAM, and it does mean that our resource management doesn't
    >>actually handle 64-bit addresses correctly.
    >>See drivers/pci/probe.c for the result:
    >> "PCI: Unable to handle 64-bit address for device xxxx"
    >>(and I do not actually think this has _ever_ happened in real life, which
    >>makes me suspect that Windows doesn't handle them either - but it
    >>inevitably will happen some day).
    > I have a vague recollection of seeing a report of an ia32 device and/or
    > machine with this property from John Fusco but am having a tough time
    > searching the archives properly for it. I do recall it being around the
    > time the remap_pfn_range() work was started, and I also claimed it as
    > one of the motivators of it in one of my posts. I'm unaware of whether
    > there are more general resources in John Fusco's situation.
    > My follow-ups began with:
    > Message-ID: <>
    > References: <>

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