linux-kernel - Re: [PATCH v2 5/5] iommu/arm-smmu: Setup identity domain for boot mappings

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

Message-ID: <20200720090338.GB11189@willie-the-truck>
Date:   Mon, 20 Jul 2020 10:03:38 +0100
From:   Will Deacon <will@...nel.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Laurentiu Tudor <laurentiu.tudor@....com>,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Jonathan Marek <jonathan@...ek.ca>,
        linux-arm-msm@...r.kernel.org,
        John Stultz <john.stultz@...aro.org>,
        Vinod Koul <vkoul@...nel.org>, jcrouse@...eaurora.org
Subject: Re: [PATCH v2 5/5] iommu/arm-smmu: Setup identity domain for boot
 mappings

On Thu, Jul 16, 2020 at 05:16:19PM -0700, Bjorn Andersson wrote:
> With many Qualcomm platforms not having functional S2CR BYPASS a
> temporary IOMMU domain, without translation, needs to be allocated in
> order to allow these memory transactions.
> 
> Unfortunately the boot loader uses the first few context banks, so
> rather than overwriting a active bank the last context bank is used and
> streams are diverted here during initialization.
> 
> This also performs the readback of SMR registers for the Qualcomm
> platform, to trigger the mechanism.
> 
> This is based on prior work by Thierry Reding and Laurentiu Tudor.
> 
> Tested-by: John Stultz <john.stultz@...aro.org>
> Tested-by: Vinod Koul <vkoul@...nel.org>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
> 
> Changes since v1:
> - Rebased to avoid conflict
> - Picked up tested-by
> 
>  drivers/iommu/arm-smmu-qcom.c | 11 +++++
>  drivers/iommu/arm-smmu.c      | 79 +++++++++++++++++++++++++++++++++--

Perhaps the CB allocator callback can help to reduce the changes to the core
driver here. What do you think?

Will