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From: James Hogan <jhogan@kernel.org>
To: Sinan Kaya <okaya@codeaurora.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 22:58:55 +0100	[thread overview]
Message-ID: <20180412215855.GB27802@saruman> (raw)
In-Reply-To: <20180412215149.GA27802@saruman>

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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.

Cheers
James

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  reply	other threads:[~2018-04-12 21:59 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 [this message]
2018-04-12 22:38       ` Sinan Kaya
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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