linux-kernel - Re: [PATCH 00/11] of: Fix DMA configuration for non-DT masters

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]

Date:   Tue, 24 Sep 2019 16:59:20 -0500
From:   Rob Herring <robh+dt@...nel.org>
To:     Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
Cc:     devicetree@...r.kernel.org, Frank Rowand <frowand.list@...il.com>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        "open list:DMA GENERIC OFFLOAD ENGINE SUBSYSTEM" 
        <dmaengine@...r.kernel.org>, etnaviv@...ts.freedesktop.org,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        xen-devel@...ts.xenproject.org, linux-tegra@...r.kernel.org,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        linux-pci@...r.kernel.org, Matthias Brugger <mbrugger@...e.com>,
        Robin Murphy <robin.murphy@....com>,
        Florian Fainelli <f.fainelli@...il.com>,
        james.quinlan@...adcom.com, Stefan Wahren <wahrenst@....net>,
        Dan Williams <dan.j.williams@...el.com>,
        freedreno <freedreno@...ts.freedesktop.org>
Subject: Re: [PATCH 00/11] of: Fix DMA configuration for non-DT masters

On Tue, Sep 24, 2019 at 1:12 PM Nicolas Saenz Julienne
<nsaenzjulienne@...e.de> wrote:
>
> Hi All,
> this series tries to address one of the issues blocking us from
> upstreaming Broadcom's STB PCIe controller[1]. Namely, the fact that
> devices not represented in DT which sit behind a PCI bus fail to get the
> bus' DMA addressing constraints.
>
> This is due to the fact that of_dma_configure() assumes it's receiving a
> DT node representing the device being configured, as opposed to the PCIe
> bridge node we currently pass. This causes the code to directly jump
> into PCI's parent node when checking for 'dma-ranges' and misses
> whatever was set there.
>
> To address this I create a new API in OF - inspired from Robin Murphys
> original proposal[2] - which accepts a bus DT node as it's input in
> order to configure a device's DMA constraints. The changes go deep into
> of/address.c's implementation, as a device being having a DT node
> assumption was pretty strong.
>
> On top of this work, I also cleaned up of_dma_configure() removing its
> redundant arguments and creating an alternative function for the special cases
> not applicable to either the above case or the default usage.
>
> IMO the resulting functions are more explicit. They will probably
> surface some hacky usages that can be properly fixed as I show with the
> DT fixes on the Layerscape platform.
>
> This was also tested on a Raspberry Pi 4 with a custom PCIe driver and
> on a Seattle AMD board.

Humm, I've been working on this issue too. Looks similar though yours
has a lot more churn and there's some other bugs I've found.

Can you test out this branch[1]. I don't have any h/w needing this,
but wrote a unittest and tested with modified QEMU.

Rob

[1] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git dma-masks