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  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:   Wed, 26 Jun 2019 09:16:46 +0200
From:   Manuel Lauss <>
To:     Christoph Hellwig <>
Cc:     Bartlomiej Zolnierkiewicz <>,
        Linux-MIPS <>,
        linux-fbdev <>,
        LKML <>
Subject: Re: [PATCH] au1200fb: don't use DMA_ATTR_NON_CONSISTENT

On Tue, Jun 25, 2019 at 2:13 PM Christoph Hellwig <> wrote:
> au1200fb allocates DMA memory using DMA_ATTR_NON_CONSISTENT, but never
> calls dma_cache_sync to synchronize the memory between the CPU and the
> device.  If it was use on a not cache coherent bus that would be fatal,
> but as far as I can tell from the naming and the mips platform
> implementation it always is used in cache coherent systems.  Remove
> the DMA_ATTR_NON_CONSISTENT flag, which is a no-op in that case.

Very early au1200 chips, on which this driver apparently was developed on,
had issues with cache coherency, but this was fixed in a later step,
none of the 3 steppings I have access to exhibit any problems
with this patch applied.

> Signed-off-by: Christoph Hellwig <>

Acked-By: Manuel Lauss <>

Powered by blists - more mailing lists