From: Greg KH <greg@kroah.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
mark.rutland@arm.com, will.deacon@arm.com
Subject: Re: [PATCH] [stable] arm64: Add work around for Arm Cortex-A55 Erratum 1024718
Date: Fri, 4 May 2018 15:15:08 -0700 [thread overview]
Message-ID: <20180504221508.GD20328@kroah.com> (raw)
In-Reply-To: <1525170364-21032-1-git-send-email-suzuki.poulose@arm.com>
On Tue, May 01, 2018 at 11:26:04AM +0100, Suzuki K Poulose wrote:
> commit ece1397cbc89c51914fae1aec729539cfd8bd62b upstream
>
> Some variants of the Arm Cortex-55 cores (r0p0, r0p1, r1p0) suffer
> from an erratum 1024718, which causes incorrect updates when DBM/AP
> bits in a page table entry is modified without a break-before-make
> sequence. The work around is to disable the hardware DBM feature
> on the affected cores. The hardware Access Flag management features
> is not affected.
>
> The hardware DBM feature is a non-conflicting capability, i.e, the
> kernel could handle cores using the feature and those without having
> the features running at the same time. So this work around is detected
> at early boot time, rather than delaying it until the CPUs are brought
> up into the kernel with MMU turned on. This also avoids other complexities
> with late CPUs turning online, with or without the hardware DBM features.
>
> Note: The upstream commit is on top of a reworked capability
> infrastructure for arm64 heterogeneous systems, which allows
> handling this later in the boot process. This backport
> is based on the original version of the patch [0]. Folded the 3
> patches into this single commit, removing the unncessary bits.
>
> [0] https://lkml.kernel.org/r/20180116102323.3470-1-suzuki.poulose@arm.com
>
> Cc: stable@vger.kernel.org # v4.3 to v4.16
This only would apply to the 4.16.y tree. Can you provide working
backports to 4.14.y, 4.9.y, and 4.4.y so I can queue them up there as
well?
thanks,
greg k-h
next prev parent reply other threads:[~2018-05-04 22:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-01 10:26 [PATCH] [stable] arm64: Add work around for Arm Cortex-A55 Erratum 1024718 Suzuki K Poulose
2018-05-04 22:15 ` Greg KH [this message]
2018-05-05 9:49 ` Suzuki K Poulose
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=20180504221508.GD20328@kroah.com \
--to=greg@kroah.com \
--cc=catalin.marinas@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=stable@vger.kernel.org \
--cc=suzuki.poulose@arm.com \
--cc=will.deacon@arm.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).