Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933339AbdGKVfV (ORCPT ); Tue, 11 Jul 2017 17:35:21 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:26299 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932159AbdGKVfT (ORCPT ); Tue, 11 Jul 2017 17:35:19 -0400 From: Tushar Dave To: davem@davemloft.net, chris.hyser@oracle.com, sowmini.varadhan@oracle.com, egtvedt@samfundet.no, dan.carpenter@oracle.com, krzk@kernel.org, bart.vanassche@sandisk.com, sparclinux@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hch@lst.de, mroos@linux.ee Subject: [sparc-next] SPARC64: Fix sun4v DMA panic Date: Tue, 11 Jul 2017 14:34:47 -0700 Message-Id: <1499808887-31483-1-git-send-email-tushar.n.dave@oracle.com> X-Mailer: git-send-email 1.9.1 X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1320 Lines: 40 64bit DMA only supported on sun4v equipped with ATU IOMMU HW. 'Commit b02c2b0bfd7ae ("sparc: remove arch specific dma_supported implementations")' introduced a code that incorrectly allow dma_supported() to succeed for 64bit dma mask even if system doesn't have ATU IOMMU. This results into panic. Fix it. Reported-by: Meelis Roos Signed-off-by: Tushar Dave --- arch/sparc/kernel/pci_sun4v.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c index 24f21c7..f10e2f7 100644 --- a/arch/sparc/kernel/pci_sun4v.c +++ b/arch/sparc/kernel/pci_sun4v.c @@ -673,12 +673,14 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist, static int dma_4v_supported(struct device *dev, u64 device_mask) { struct iommu *iommu = dev->archdata.iommu; - u64 dma_addr_mask; + u64 dma_addr_mask = iommu->dma_addr_mask; - if (device_mask > DMA_BIT_MASK(32) && iommu->atu) - dma_addr_mask = iommu->atu->dma_addr_mask; - else - dma_addr_mask = iommu->dma_addr_mask; + if (device_mask > DMA_BIT_MASK(32)) { + if (iommu->atu) + dma_addr_mask = iommu->atu->dma_addr_mask; + else + return 0; + } if ((device_mask & dma_addr_mask) == dma_addr_mask) return 1; -- 1.9.1