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Date: Mon, 29 Feb 2016 15:17:49 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Brian Starkey <brian.starkey@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 4/4] drivers: dma-coherent: use memset_io for
 DMA_MEMORY_IO mappings
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On Mon, 29 Feb 2016 16:09:24 +0000 Brian Starkey <brian.starkey@arm.com> wrote:

> Use memset_io() for DMA_MEMORY_IO mappings which are mapped as I/O
> memory, and regular memset() for DMA_MEMORY_MAP mappings.
> 
> This fixes the below alignment fault on arm64 for DMA_MEMORY_IO
> mappings, where memset() uses the DC ZVA instruction which is
> invalid on device memory.

What's the urgency of this fix?  "Hair on fire needed in stable asap"
or "Nice to have in there for 4.6" or what?