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Re: Modpost warning on Alchemy

To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: Modpost warning on Alchemy
From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Date: Wed, 01 Aug 2007 20:01:40 +0400
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>, Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
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Alan Cox wrote:

   Even on a CPU with 36-bit physical address? ;-)

Nope. This is one problem for example with ioremap on a Pentium Pro.

Well, but we only consider MIPS processors here which do not have such odd restrictions resulting from bad design decisions in the past. ;-) The 32-bit TLB entry format allows for up to 36 bits of the physical address space (34 bits if support for the page size of 1kB has been

So does the Pentium Pro. We can map 36bit physical addresses.

enabled). For anything beyond that you need a 64-bit MIPS processor using the 64-bit TLB entry format.

Your problem is a little higher up the stack. ioremap takes an unsigned
long, which on a 32bit system usually means you can't give it a 36bit bus
address to remap.

It takes phys_t, which is 'unsigned long long' for this platform that has CONFIG_64BUIT_PHYS_ADDR=y. The reall issue is the size.

Alan

WBR, Sergei

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