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Subject: Re: [PATCH] powerpc: warn on emulation of dcbz instruction
From:   Benjamin Herrenschmidt <benh@kernel.crashing.org>
To:     David Laight <David.Laight@ACULAB.COM>,
        "'Christophe Leroy'" <christophe.leroy@csgroup.eu>,
        Paul Mackerras <paulus@samba.org>,
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        Finn Thain <fthain@linux-m68k.org>
Date:   Fri, 17 Sep 2021 22:33:46 +1000
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On Thu, 2021-09-16 at 14:36 +0000, David Laight wrote:
> > Does userspace accesses non-cached memory directly ?
> 
> 
> It probably can if a driver mmaps PCI space directly into user space.
> 
> That certainly works on x86-64.

The posterchild for that is Xorg

Cheers,
Ben.