From: Sinan Kaya <okaya@codeaurora.org>
To: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org, arnd@arndb.de, timur@codeaurora.org,
sulrich@codeaurora.org, linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] MIPS: io: add a barrier after register read in readX()
Date: Thu, 12 Apr 2018 18:38:39 -0400 [thread overview]
Message-ID: <33c9c074-e0a5-7552-9993-269cd85101aa@codeaurora.org> (raw)
In-Reply-To: <20180412215855.GB27802@saruman>
On 4/12/2018 5:58 PM, James Hogan wrote:
> On Thu, Apr 12, 2018 at 10:51:49PM +0100, James Hogan wrote:
>> On Tue, Apr 03, 2018 at 08:55:04AM -0400, Sinan Kaya wrote:
>>> While a barrier is present in writeX() function before the register write,
>>> a similar barrier is missing in the readX() function after the register
>>> read. This could allow memory accesses following readX() to observe
>>> stale data.
>>>
>>> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
>>> Reported-by: Arnd Bergmann <arnd@arndb.de>
>>
>> Both patches look like obvious improvements to me, so I'm happy to apply
>> to my fixes branch.
>
> Though having said that, a comment to go with the rmb() (as suggested by
> checkpatch) to detail the situation we're concerned about would be nice
> to have.
I can send a new version. No worries.
Functional correctness is more important at this moment. I can accommodate
any nice to haves.
>
> Cheers
> James
>
--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
next prev parent reply other threads:[~2018-04-12 22:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-03 12:55 [PATCH v3 1/2] MIPS: io: prevent compiler reordering on the default writeX() implementation Sinan Kaya
2018-04-03 12:55 ` [PATCH v3 2/2] MIPS: io: add a barrier after register read in readX() Sinan Kaya
2018-04-06 1:34 ` Sinan Kaya
2018-04-06 18:15 ` Sinan Kaya
2018-04-06 21:26 ` James Hogan
2018-04-07 21:43 ` Sinan Kaya
2018-04-11 17:10 ` Sinan Kaya
2018-04-11 20:26 ` James Hogan
2018-04-11 20:48 ` Sinan Kaya
2018-04-11 17:04 ` Maciej W. Rozycki
2018-04-12 21:51 ` James Hogan
2018-04-12 21:58 ` James Hogan
2018-04-12 22:38 ` Sinan Kaya [this message]
2018-04-12 22:20 ` Sinan Kaya
2018-04-13 15:41 ` David Laight
2018-04-13 16:36 ` Sinan Kaya
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