Re: [Xen-devel] 2.6.27-rc1 >4096MB issue

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>>> Jeremy Fitzhardinge <jeremy@xxxxxxxx> 05.08.08 05:07 >>>
>Subject: make PFN_PHYS explicitly return 64-bit result
>
>PFN_PHYS, as its name suggests, turns a pfn into a physical address.
>However, it is a macro which just operates on its argument without
>modifying its type.  pfns are typed unsigned long, but an unsigned
>long may not be long enough to hold a physical address (32-bit systems
>with more than 32 bits of physcial address).  This means that the
>resulting address could be truncated if it doesn't fit within an
>unsigned long.  This isn't generally a problem because most users end
>up using it for "low" memory, but there's no reason why PFN_PHYS
>couldn't be used for any possible pfn.
>
>Unfortunately there's no univerally recognized type for holding a full
>physical address, so this patch makes it always return a u64 result.

Couldn't you use resource_size_t here?

Jan


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