linux-kernel - Re: provide in-place uncached remapping for dma-direct v2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4fe14c57-78d4-6590-a4c4-14fbe061238e@arm.com>
Date:   Mon, 2 Mar 2020 16:05:12 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Christoph Hellwig <hch@....de>, Jonas Bonn <jonas@...thpole.se>,
        Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
        Stafford Horne <shorne@...il.com>
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        openrisc@...ts.librecores.org, iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: provide in-place uncached remapping for dma-direct v2

On 24/02/2020 7:44 pm, Christoph Hellwig wrote:
> Hi all,
> 
> this series provides support for remapping places uncached in-place in
> the generic dma-direct code, and moves openrisc over from its own
> in-place remapping scheme.  The arm64 folks also had interest in such
> a scheme to avoid problems with speculating into cache aliases.
> 
> Also all architectures that always use small page mappings for the
> kernel and have non-coherent DMA should look into enabling this
> scheme, as it is much more efficient than the vmap remapping.
> 
> Changes since v1:
>   - share the arch hook for inline remap and uncached segment support
> 

For the whole series:

Reviewed-by: Robin Murphy <robin.murphy@....com>

I think we might ultimately want to fiddle around a bit more in 
dma_direct_alloc_pages() to give ARCH_HAS_DMA_SET_UNCACHED clear 
precedence over DMA_DIRECT_REMAP if they have to coexist, but let's land 
these patches first as a solid foundation.

Thanks,
Robin.