Messages in this thread | | | Date | Mon, 10 Jan 2005 18:05:50 -0800 | From | William Lee Irwin III <> | Subject | Re: clean way to support >32bit addr on 32bit CPU |
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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>
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