From 2ad67141f1e47dc063b202993835361a06239aaa Mon Sep 17 00:00:00 2001 From: Tushar Dave Date: Tue, 11 Jul 2017 14:34:47 -0700 Subject: [PATCH] SPARC64: Fix sun4v DMA panic 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 Reviewed-by: Christoph Hellwig Signed-off-by: David S. Miller --- 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 24f21c726dfa..f10e2f712394 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; -- GitLab