From: Will Deacon <will@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Joerg Roedel <joro@8bytes.org>,
Zhou Wang <wangzhou1@hisilicon.com>
Cc: Will Deacon <will@kernel.org>,
catalin.marinas@arm.com, linuxarm@huawei.com,
iommu@lists.linux-foundation.org, kernel-team@android.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] iommu/arm-smmu-v3: Add rmb after reading event queue prod_reg
Date: Mon, 28 Sep 2020 23:13:22 +0100 [thread overview]
Message-ID: <160132830305.1858738.13352352759100546799.b4-ty@kernel.org> (raw)
In-Reply-To: <1601281922-117296-1-git-send-email-wangzhou1@hisilicon.com>
On Mon, 28 Sep 2020 16:32:02 +0800, Zhou Wang wrote:
> In arm_smmu_evtq_thread, reading event queue is from consumer pointer,
> which has no address dependency on producer pointer, prog_reg(MMIO) and
> event queue memory(Normal memory) can disorder. So the load for event queue
> can be done before the load of prod_reg, then perhaps wrong event entry
> value will be got.
>
> Add rmb to make sure to get correct event queue entry value.
Applied to will (for-joerg/arm-smmu/updates), thanks!
[1/1] iommu/arm-smmu-v3: Add rmb after reading event queue prod_reg
https://git.kernel.org/will/c/a76a37777f2c
(please note that I changed the patch to use readl() instead of an rmb()
in conjunction with the _relaxed() accessor, and then adjusted the cons
side to match in terms of DMB vs DSB).
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-09-28 22:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-28 8:32 [PATCH] iommu/arm-smmu-v3: Add rmb after reading event queue prod_reg Zhou Wang
2020-09-28 22:13 ` Will Deacon [this message]
2020-09-29 11:15 ` Zhou Wang
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=160132830305.1858738.13352352759100546799.b4-ty@kernel.org \
--to=will@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jean-philippe@linaro.org \
--cc=joro@8bytes.org \
--cc=kernel-team@android.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linuxarm@huawei.com \
--cc=robin.murphy@arm.com \
--cc=wangzhou1@hisilicon.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).