From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>
Cc: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Yang Li <pku.leo-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH v3 3/3] arm64: Force swiotlb bounce buffering for non-coherent DMA with large CWG
Date: Sat, 12 May 2018 14:38:29 +0200 [thread overview]
Message-ID: <20180512123829.GA8024@lst.de> (raw)
In-Reply-To: <20180511135547.34521-4-catalin.marinas-5wv7dgnIgG8@public.gmane.org>
On Fri, May 11, 2018 at 02:55:47PM +0100, Catalin Marinas wrote:
> On systems with a Cache Writeback Granule (CTR_EL0.CWG) greater than
> ARCH_DMA_MINALIGN, DMA cache maintenance on sub-CWG ranges is not safe,
> leading to data corruption. If such configuration is detected, the
> kernel will force swiotlb bounce buffering for all non-coherent devices.
Per the previous discussion I understand that so far this is a
purely theoretical condition. Given that I'd rather avoid commiting
this patch and just refuse too boot in this case.
In a merge window or two I plan to have a noncoherent flag in struct
device, at which point we can handle this entirely in common code.
WARNING: multiple messages have this Message-ID (diff)
From: hch@lst.de (Christoph Hellwig)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 3/3] arm64: Force swiotlb bounce buffering for non-coherent DMA with large CWG
Date: Sat, 12 May 2018 14:38:29 +0200 [thread overview]
Message-ID: <20180512123829.GA8024@lst.de> (raw)
In-Reply-To: <20180511135547.34521-4-catalin.marinas@arm.com>
On Fri, May 11, 2018 at 02:55:47PM +0100, Catalin Marinas wrote:
> On systems with a Cache Writeback Granule (CTR_EL0.CWG) greater than
> ARCH_DMA_MINALIGN, DMA cache maintenance on sub-CWG ranges is not safe,
> leading to data corruption. If such configuration is detected, the
> kernel will force swiotlb bounce buffering for all non-coherent devices.
Per the previous discussion I understand that so far this is a
purely theoretical condition. Given that I'd rather avoid commiting
this patch and just refuse too boot in this case.
In a merge window or two I plan to have a noncoherent flag in struct
device, at which point we can handle this entirely in common code.
next prev parent reply other threads:[~2018-05-12 12:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-11 13:55 [PATCH v3 0/3] arm64: Revert L1_CACHE_SHIFT back to 6 (64-byte cache line size) Catalin Marinas
2018-05-11 13:55 ` Catalin Marinas
[not found] ` <20180511135547.34521-1-catalin.marinas-5wv7dgnIgG8@public.gmane.org>
2018-05-11 13:55 ` [PATCH v3 1/3] Revert "arm64: Increase the max granular size" Catalin Marinas
2018-05-11 13:55 ` Catalin Marinas
2018-05-11 13:55 ` [PATCH v3 2/3] arm64: Increase ARCH_DMA_MINALIGN to 128 Catalin Marinas
2018-05-11 13:55 ` Catalin Marinas
2018-05-11 13:55 ` [PATCH v3 3/3] arm64: Force swiotlb bounce buffering for non-coherent DMA with large CWG Catalin Marinas
2018-05-11 13:55 ` Catalin Marinas
[not found] ` <20180511135547.34521-4-catalin.marinas-5wv7dgnIgG8@public.gmane.org>
2018-05-12 12:38 ` Christoph Hellwig [this message]
2018-05-12 12:38 ` Christoph Hellwig
[not found] ` <20180512123829.GA8024-jcswGhMUV9g@public.gmane.org>
2018-05-14 14:57 ` Catalin Marinas
2018-05-14 14:57 ` Catalin Marinas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180512123829.GA8024@lst.de \
--to=hch-jcswghmuv9g@public.gmane.org \
--cc=catalin.marinas-5wv7dgnIgG8@public.gmane.org \
--cc=iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org \
--cc=linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org \
--cc=pku.leo-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=will.deacon-5wv7dgnIgG8@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.