From: Christoph Hellwig <hch@infradead.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Duan <fugang.duan@nxp.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
Christoph Hellwig <hch@infradead.org>,
Robin Murphy <robin.murphy@arm.com>,
"bjorn.andersson@linaro.org" <bjorn.andersson@linaro.org>,
"ohad@wizery.com" <ohad@wizery.com>,
"linux-remoteproc@vger.kernel.org"
<linux-remoteproc@vger.kernel.org>,
"anup@brainfault.org" <anup@brainfault.org>,
"loic.pallardy@st.com" <loic.pallardy@st.com>,
dl-linux-imx <linux-imx@nxp.com>,
Richard Zhu <hongxing.zhu@nxp.com>,
Jason Liu <jason.hui.liu@nxp.com>, Peng Fan <peng.fan@nxp.com>
Subject: Re: [rpmsg PATCH v2 1/1] rpmsg: virtio_rpmsg_bus: fix unexpected huge vmap mappings
Date: Wed, 26 Dec 2018 06:50:48 -0800 [thread overview]
Message-ID: <20181226145048.GA24307@infradead.org> (raw)
In-Reply-To: <CAKv+Gu-zfTZAZfiQt1iUn9otqeDkJP-y-siuBUrWUR-Kq=BsVQ@mail.gmail.com>
On Wed, Dec 26, 2018 at 01:27:25PM +0100, Ard Biesheuvel wrote:
> If there are legal uses for vmalloc_to_page() even if the region is
> not mapped down to pages [which appears to be the case here], I'd
> prefer to fix vmalloc_to_page() instead of adding this hack. Or
> perhaps we need a sg_xxx helper that translates any virtual address
> (vmalloc or otherwise) into a scatterlist entry?
What rpmsg does is completely bogus and needs to be fixed ASAP. The
virtual address returned from dma_alloc_coherent must not be passed to
virt_to_page or vmalloc_to_page, but only use as a kernel virtual
address. It might not be backed by pages, or might create aliases that
must not be used with VIVT caches.
rpmsg needs to either stop trying to extract pages from
dma_alloc_coherent, or just replace its use of dma_alloc_coherent
with the normal page allocator and the streaming DMA API.
next prev parent reply other threads:[~2018-12-26 14:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-26 8:25 Andy Duan
2018-12-26 12:27 ` Ard Biesheuvel
2018-12-26 12:27 ` Ard Biesheuvel
2018-12-26 14:50 ` Christoph Hellwig [this message]
2018-12-27 2:36 ` Andy Duan
2018-12-27 12:19 ` Christoph Hellwig
2018-12-28 1:48 ` Andy Duan
2019-01-10 1:45 ` Andy Duan
2019-01-10 13:06 ` Loic PALLARDY
2019-01-11 1:56 ` Andy Duan
2019-01-10 14:07 ` Christoph Hellwig
2019-01-11 1:28 ` Andy Duan
2019-01-14 9:53 ` Christoph Hellwig
2019-01-16 3:38 ` Andy Duan
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