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Date: Thu, 19 Jun 2008 09:13:09 -0700 (PDT)
From: Sanjay Patel <sanjay3000@yahoo.com>
Subject: Re: [RFC 1/3] powerpc: __copy_tofrom_user tweaked for Cell
To: Arnd Bergmann <arnd@arndb.de>, Gunnar von Boehn <VONBOEHN@de.ibm.com>
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--- On Thu, 6/19/08, Gunnar von Boehn <VONBOEHN@de.ibm.com> wrote:

> You are right the main copy2user requires that the SRC is
> cacheable.
> IMHO because of the exception on load, the routine should
> fallback to the
> byte copy loop.
> 
> Arnd, could you verify that it works on localstore?

Since the main loops use 'dcbz', the destination must also be cacheable. IIRC, if the destination is write-through or cache-inhibited, the 'dcbz' will cause an alignment exception. I suppose it would still function correctly via the handler, but horribly slowly.

--Sanjay