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.
next prev parent reply other threads:[~2021-11-02 6:44 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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