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Re: [PATCH 0/2] FLATMEM: allow memory to start at pfn != 0 [take #2]

To: Franck Bui-Huu <vagabon.xyz@gmail.com>
Subject: Re: [PATCH 0/2] FLATMEM: allow memory to start at pfn != 0 [take #2]
From: tsbogend@alpha.franken.de (Thomas Bogendoerfer)
Date: Wed, 7 Mar 2007 14:18:42 +0100
Cc: mbizon@freebox.fr, linux-mips <linux-mips@linux-mips.org>
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On Tue, Mar 06, 2007 at 10:39:59PM +0100, Franck Bui-Huu wrote:
> I think you missed PAGE_OFFSET meaning...
> 
> PAGE_OFFSET is the start of the kernel virtual address space and
> before this patchset pa(PAGE_OFFSET) was always 0.
> 
> In your case, you said:
> 
>        PAGE_OFFSET = 0x80000000
>        PHYS_OFFSET = 0x10000000
> 
> this means that the first kernel virtual address is 0x80000000 and the
> corresponding physical address is 0x10000000. If you load your kernel
> at 0x9000xxxx, it will be loaded in physical memory located at
> 0x2000xxxx which is obviously not what you want.

which sound like a very bogus setup for at leat 32bit MIPS. The mapping
virtual 0x80000000 to physical 0x00000000 is a CPU thing and can't
be changed.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessary a
good idea.                                                [ RFC1925, 2.3 ]

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