[lkml]   [2005]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
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: <>

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:09    [W:0.048 / U:33.964 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site