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From: Christoph Hellwig <hch@lst.de>
To: LABBE Corentin <clabbe@baylibre.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Ben Dooks <ben.dooks@codethink.co.uk>,
	herbert@gondor.apana.org.au, heiko@sntech.de,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-sunxi@lists.linux.dev
Subject: Re: [RFC PATCH] crypto: flush poison data
Date: Tue, 5 Jul 2022 19:58:34 +0200	[thread overview]
Message-ID: <20220705175834.GA15815@lst.de> (raw)
In-Reply-To: <YsR7O4q4IRI14Wkc@Red>

On Tue, Jul 05, 2022 at 07:56:11PM +0200, LABBE Corentin wrote:
> My problem is that a dma_sync on the data buffer corrupt the poison buffer as collateral dommage.
> Probably because the sync operate on a larger region than the requested dma_sync length.
> So I try to flush poison data in the cryptoAPI.

Data structures that are DMAed to must be aligned to
the value returned by dma_get_cache_alignment(), as non-coherent DMA
by definition can disturb the data inside that boundary.  That is not
a bug but fundamentally part of how DMA works when the device attachment
is not cache coherent.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: LABBE Corentin <clabbe@baylibre.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Ben Dooks <ben.dooks@codethink.co.uk>,
	herbert@gondor.apana.org.au, heiko@sntech.de,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-sunxi@lists.linux.dev
Subject: Re: [RFC PATCH] crypto: flush poison data
Date: Tue, 5 Jul 2022 19:58:34 +0200	[thread overview]
Message-ID: <20220705175834.GA15815@lst.de> (raw)
In-Reply-To: <YsR7O4q4IRI14Wkc@Red>

On Tue, Jul 05, 2022 at 07:56:11PM +0200, LABBE Corentin wrote:
> My problem is that a dma_sync on the data buffer corrupt the poison buffer as collateral dommage.
> Probably because the sync operate on a larger region than the requested dma_sync length.
> So I try to flush poison data in the cryptoAPI.

Data structures that are DMAed to must be aligned to
the value returned by dma_get_cache_alignment(), as non-coherent DMA
by definition can disturb the data inside that boundary.  That is not
a bug but fundamentally part of how DMA works when the device attachment
is not cache coherent.

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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2022-07-05 17:58 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-01 13:27 [RFC PATCH] crypto: flush poison data Corentin Labbe
2022-07-01 13:27 ` Corentin Labbe
2022-07-01 13:35 ` Ben Dooks
2022-07-01 13:35   ` Ben Dooks
2022-07-05  8:21   ` LABBE Corentin
2022-07-05  8:21     ` LABBE Corentin
2022-07-05 16:42     ` Christoph Hellwig
2022-07-05 16:42       ` Christoph Hellwig
2022-07-05 17:56       ` LABBE Corentin
2022-07-05 17:56         ` LABBE Corentin
2022-07-05 17:58         ` Christoph Hellwig [this message]
2022-07-05 17:58           ` Christoph Hellwig
2022-07-06  7:25           ` LABBE Corentin
2022-07-06  7:25             ` LABBE Corentin
2022-07-06  9:47       ` Ben Dooks
2022-07-06  9:47         ` Ben Dooks
2022-07-06 11:58         ` Christoph Hellwig
2022-07-06 11:58           ` Christoph Hellwig
2022-07-06 12:23           ` LABBE Corentin
2022-07-06 12:23             ` LABBE Corentin
2022-07-01 14:36 ` Andre Przywara
2022-07-01 14:36   ` Andre Przywara
2022-07-01 14:55   ` LABBE Corentin
2022-07-01 14:55     ` LABBE Corentin

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