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From: Zhou Wang <wangzhou1@hisilicon.com>
To: Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Joerg Roedel <joro@8bytes.org>
Cc: catalin.marinas@arm.com, iommu@lists.linux-foundation.org,
	kernel-team@android.com, linuxarm@huawei.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] iommu/arm-smmu-v3: Add rmb after reading event queue prod_reg
Date: Tue, 29 Sep 2020 19:15:32 +0800	[thread overview]
Message-ID: <5F731754.5040609@hisilicon.com> (raw)
In-Reply-To: <160132830305.1858738.13352352759100546799.b4-ty@kernel.org>

On 2020/9/29 6:13, Will Deacon wrote:
> 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).

Thanks for taking this patch!

Best,
Zhou

> 
> Cheers,
> 
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Zhou Wang <wangzhou1@hisilicon.com>
To: Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Joerg Roedel <joro@8bytes.org>
Cc: catalin.marinas@arm.com, iommu@lists.linux-foundation.org,
	kernel-team@android.com, linuxarm@huawei.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] iommu/arm-smmu-v3: Add rmb after reading event queue prod_reg
Date: Tue, 29 Sep 2020 19:15:32 +0800	[thread overview]
Message-ID: <5F731754.5040609@hisilicon.com> (raw)
In-Reply-To: <160132830305.1858738.13352352759100546799.b4-ty@kernel.org>

On 2020/9/29 6:13, Will Deacon wrote:
> 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).

Thanks for taking this patch!

Best,
Zhou

> 
> Cheers,
> 

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-09-29 11:15 UTC|newest]

Thread overview: 6+ 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  8:32 ` Zhou Wang
2020-09-28 22:13 ` Will Deacon
2020-09-28 22:13   ` Will Deacon
2020-09-29 11:15   ` Zhou Wang [this message]
2020-09-29 11:15     ` Zhou Wang

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