* [sparc-next] SPARC64: Fix sun4v DMA panic
@ 2017-07-11 21:34 Tushar Dave
2017-07-12 7:21 ` Christoph Hellwig
2017-07-12 15:13 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Tushar Dave @ 2017-07-11 21:34 UTC (permalink / raw)
To: davem, chris.hyser, sowmini.varadhan, egtvedt, dan.carpenter,
krzk, bart.vanassche, sparclinux
Cc: linux-kernel, hch, mroos
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 <mroos@linux.ee>
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [sparc-next] SPARC64: Fix sun4v DMA panic
2017-07-11 21:34 [sparc-next] SPARC64: Fix sun4v DMA panic Tushar Dave
@ 2017-07-12 7:21 ` Christoph Hellwig
2017-07-12 15:13 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2017-07-12 7:21 UTC (permalink / raw)
To: Tushar Dave
Cc: davem, chris.hyser, sowmini.varadhan, egtvedt, dan.carpenter,
krzk, bart.vanassche, sparclinux, linux-kernel, hch, mroos
On Tue, Jul 11, 2017 at 02:34:47PM -0700, Tushar Dave wrote:
> 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 <mroos@linux.ee>
> Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
> ---
> 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;
> + }
This would be more readable as:
if (device_mask > DMA_BIT_MASK(32)) {
if (!iommu->atu)
return 0;
dma_addr_mask = iommu->atu->dma_addr_mask;
}
But except for that it looks fine to me:
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [sparc-next] SPARC64: Fix sun4v DMA panic
2017-07-11 21:34 [sparc-next] SPARC64: Fix sun4v DMA panic Tushar Dave
2017-07-12 7:21 ` Christoph Hellwig
@ 2017-07-12 15:13 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2017-07-12 15:13 UTC (permalink / raw)
To: tushar.n.dave
Cc: chris.hyser, sowmini.varadhan, egtvedt, dan.carpenter, krzk,
bart.vanassche, sparclinux, linux-kernel, hch, mroos
From: Tushar Dave <tushar.n.dave@oracle.com>
Date: Tue, 11 Jul 2017 14:34:47 -0700
> 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 <mroos@linux.ee>
> Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Applied to the 'sparc' tree, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-07-12 7:21 ` Christoph Hellwig
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