Messages in this thread | | | Date | Mon, 10 Jan 2005 19:38:57 -0800 | From | "Randy.Dunlap" <> | Subject | Re: clean way to support >32bit addr on 32bit CPU |
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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: <20040924021735.GL9106@holomorphy.com> > References: <41535AAE.6090700@yahoo.com>
http://marc.theaimsgroup.com/?l=linux-mm&m=109598180125156&w=2
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