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:   Wed, 16 Sep 2020 15:56:40 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Phil Chang <phil.chang@...iatek.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Jonathan Corbet <corbet@....net>,
        Will Deacon <will@...nel.org>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        YJ Chiang <yj.chiang@...iatek.com>,
        Alix Wu <alix.wu@...iatek.com>,
        Mike Rapoport <rppt@...nel.org>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH] [PATCH] ARM64: Setup DMA32 zone size by bootargs

On Wed, Sep 16, 2020 at 09:33:24PM +0800, Phil Chang wrote:
> this patch allowing the DMA32 zone be configurable in ARM64.
> For some devices, the main memory split into 2 part due to the memory
> architecture, the efficient and less inefficient part.
> One of the use case is fine-tune the dma32 size to contain all the
> efficient part of memory block on this kind of architecture
> 
> Signed-off-by: Alix Wu <alix.wu@...iatek.com>
> Signed-off-by: YJ Chiang <yj.chiang@...iatek.com>
> Signed-off-by: Phil Chang <phil.chang@...iatek.com>
> ---
> Hi
> 
> supplement the reason of this usage.

That's really not a good enough justification to merge such patch. As
Christoph said, DMA32 is defined as addressing the first 4GB of RAM.

Is the memory inefficient (presumably slow) for device or for the CPU?
Maybe you can pretend it's a separate NUMA node for the CPU.
Alternatively, change your device DMA coherent mask and allocate only
from ZONE_DMA (currently first 1GB on arm64).

-- 
Catalin

Powered by blists - more mailing lists