From: Christoph Hellwig <hch@lst.de>
To: Walter Wu <walter-zh.wu@mediatek.com>
Cc: Ard Biesheuvel <ardb@kernel.org>, Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Linux IOMMU <iommu@lists.linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
wsd_upstream <wsd_upstream@mediatek.com>,
linux-mediatek@lists.infradead.org,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH] dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING
Date: Tue, 2 Nov 2021 07:43:56 +0100 [thread overview]
Message-ID: <20211102064356.GB27749@lst.de> (raw)
In-Reply-To: <c9f74d817aa1ae1cceaee9ec226d39bbdf2c5c48.camel@mediatek.com>
On Tue, Nov 02, 2021 at 11:21:16AM +0800, Walter Wu wrote:
> Our platform is arch64. We need a dynamic allocated buffer from CMA is
> not to read by CPU peculative execution, so we need to remove its
> kernel mapping.
If your CPU speculates into unused kernel direct mappings your have
a worse problem than this, because all the dma coherent allocations for
non-coherent devices still have a cachable direct mapping. Will
mentioned he wanted to look into getting rid of that mapping now that
the core dma code has the infrastucture for that, so adding him here.
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next prev parent reply other threads:[~2021-11-02 6:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 3:15 [PATCH] dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING Walter Wu
2021-11-01 6:10 ` kernel test robot
2021-11-01 8:34 ` Ard Biesheuvel
2021-11-01 12:20 ` Walter Wu
2021-11-01 14:17 ` Ard Biesheuvel
2021-11-02 3:21 ` Walter Wu
2021-11-02 6:43 ` Christoph Hellwig [this message]
2021-11-01 10:29 ` Robin Murphy
2021-11-01 12:07 ` Walter Wu
2021-11-02 6:41 ` Christoph Hellwig
2021-11-02 7:08 ` Walter Wu
2021-11-02 7:26 ` Walter Wu
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