Re: [PATCH 1 of 3] add phys_addr_t for holding physical addresses

[Jeremy Fitzhardinge]

Andrew Morton wrote:
> On Tue, 19 Aug 2008 13:02:50 -0700
> Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>
>   
>> Add a kernel-wide "phys_addr_t" which is guaranteed to be able to hold
>> any physical address.  By default it equals the word size of the
>> architecture, but a 32-bit architecture can set ARCH_PHYS_ADDR_T_64BIT
>> if it needs a 64-bit phys_addr_t.
>>
>>     
>
> You say this is a bugfix but you don't describe the bug.  This makes it
> rather hard to make the 2.6.2[5678] decisions.
>
> Ditto on [patch 2/3].
>   

1/3 is not a bugfix in itself, but a pre-requisite for 2/3.

2/3 replaces an ad-hoc Xen fix with a general fix to prevent address
truncation when using PFN_PHYS() on any PFN above the 4G mark.  The Xen
crash is the only bug I know of that's directly attributable to this,
and it was already addressed in older kernels with the casts in the Xen
code that this patch removes.

So I don't think there's any strong need to push this to earlier kernels.

    J
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