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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gWgdc-0005wd-Bj; Tue, 11 Dec 2018 11:55:44 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gWgdZ-0005vH-AV for linux-arm-kernel@lists.infradead.org; Tue, 11 Dec 2018 11:55:42 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 04D09EBD; Tue, 11 Dec 2018 03:55:31 -0800 (PST) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.113]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E9D353F6A8; Tue, 11 Dec 2018 03:55:29 -0800 (PST) Date: Tue, 11 Dec 2018 11:55:27 +0000 From: Catalin Marinas To: Will Deacon Subject: Re: [PATCH] arm64: dma-mapping: Fix FORCE_CONTIGUOUS buffer clearing Message-ID: <20181211115526.GD35824@arrakis.emea.arm.com> References: <9bd208e9187db7a934428fe44ae0906028a8c9c3.1544469820.git.robin.murphy@arm.com> <20181210193618.GC8923@edgewater-inn.cambridge.arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20181210193618.GC8923@edgewater-inn.cambridge.arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181211_035541_367836_C5020499 X-CRM114-Status: GOOD ( 17.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Robin Murphy , hch@lst.de, linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 > > --- > > 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 > > Catalin, please take this with a Cc stable. Queued. Thanks. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel