From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Date: Tue, 4 Apr 2017 12:10:51 +0100 Message-ID: <906032bd-8f3d-f34c-7c0f-0222c39fb552@arm.com> References: <1489086061-9356-1-git-send-email-sricharan@codeaurora.org> <1491301105-5274-1-git-send-email-sricharan@codeaurora.org> <1491301105-5274-7-git-send-email-sricharan@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1491301105-5274-7-git-send-email-sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Sricharan R , will.deacon-5wv7dgnIgG8@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tn-nYOzD4b6Jr9Wk0Htik3J/w@public.gmane.org, hanjun.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, okaya-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sudeep.holla-5wv7dgnIgG8@public.gmane.org, rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org, lenb-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, catalin.marinas-5wv7dgnIgG8@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On 04/04/17 11:18, Sricharan R wrote: > Size of the dma-range is calculated as coherent_dma_mask + 1 > and passed to arch_setup_dma_ops further. It overflows when > the coherent_dma_mask is set for full 64 bits 0xFFFFFFFFFFFFFFFF, > resulting in size getting passed as 0 wrongly. Fix this by > passsing in max(mask, mask + 1). Note that in this case > when the mask is set to full 64bits, we will be passing the mask > itself to arch_setup_dma_ops instead of the size. The real fix > for this should be to make arch_setup_dma_ops receive the > mask and handle it, to be done in the future. Agreed; in the meantime, this fix is neat and robust enough. Reviewed-by: Robin Murphy > Signed-off-by: Sricharan R > --- > drivers/of/device.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/of/device.c b/drivers/of/device.c > index c17c19d..c2ae6bb 100644 > --- a/drivers/of/device.c > +++ b/drivers/of/device.c > @@ -107,7 +107,7 @@ void of_dma_configure(struct device *dev, struct device_node *np) > ret = of_dma_get_range(np, &dma_addr, &paddr, &size); > if (ret < 0) { > dma_addr = offset = 0; > - size = dev->coherent_dma_mask + 1; > + size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); > } else { > offset = PFN_DOWN(paddr - dma_addr); > dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset); >