From: Catalin Marinas <catalin.marinas@arm.com>
To: Will Deacon <will.deacon@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
hch@lst.de, linux-arm-kernel@lists.infradead.org,
m.szyprowski@samsung.com
Subject: Re: [PATCH] arm64: dma-mapping: Fix FORCE_CONTIGUOUS buffer clearing
Date: Tue, 11 Dec 2018 11:55:27 +0000 [thread overview]
Message-ID: <20181211115526.GD35824@arrakis.emea.arm.com> (raw)
In-Reply-To: <20181210193618.GC8923@edgewater-inn.cambridge.arm.com>
On Mon, Dec 10, 2018 at 07:36:18PM +0000, Will Deacon wrote:
> On Mon, Dec 10, 2018 at 07:33:31PM +0000, Robin Murphy wrote:
> > We need to invalidate the caches *before* clearing the buffer via the
> > non-cacheable alias, else in the worst case __dma_flush_area() may
> > write back dirty lines over the top of our nice new zeros.
> >
> > Fixes: dd65a941f6ba ("arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag")
> > Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> > ---
> > arch/arm64/mm/dma-mapping.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> > index a3ac26284845..a53704406099 100644
> > --- a/arch/arm64/mm/dma-mapping.c
> > +++ b/arch/arm64/mm/dma-mapping.c
> > @@ -429,9 +429,9 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
> > prot,
> > __builtin_return_address(0));
> > if (addr) {
> > - memset(addr, 0, size);
> > if (!coherent)
> > __dma_flush_area(page_to_virt(page), iosize);
> > + memset(addr, 0, size);
> > } else {
> > iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
> > dma_release_from_contiguous(dev, page,
>
> Oh crikey, well spotted!
>
> Acked-by: Will Deacon <will.deacon@arm.com>
>
> Catalin, please take this with a Cc stable.
Queued. Thanks.
--
Catalin
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next prev parent reply other threads:[~2018-12-11 11:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-10 19:33 [PATCH] arm64: dma-mapping: Fix FORCE_CONTIGUOUS buffer clearing Robin Murphy
2018-12-10 19:36 ` Will Deacon
2018-12-11 11:55 ` Catalin Marinas [this message]
2018-12-12 7:31 ` Chintan Pandya
2018-12-12 7:37 ` Christoph Hellwig
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