On Tue, Jan 27, 2015 at 11:12:32AM +0000, Robin Murphy wrote:
> On 23/01/15 22:32, Murali Karicheri wrote:
> > Limit the dma_mask to minimum of dma_mask and dma_base + size - 1.
> >
> > Also arm_iommu_create_mapping() has size parameter of size_t and
> > arm_setup_iommu_dma_ops() can take a value higher than that. So
> > limit the size to SIZE_MAX.
> >
> > Signed-off-by: Murali Karicheri <m-kariche...@ti.com>
> > ---
> > arch/arm/mm/dma-mapping.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> > index 7864797..a1f9030 100644
> > --- a/arch/arm/mm/dma-mapping.c
> > +++ b/arch/arm/mm/dma-mapping.c
> > @@ -2004,6 +2004,13 @@ static bool arm_setup_iommu_dma_ops(struct device
> > *dev, u64 dma_base, u64 size,
> > if (!iommu)
> > return false;
> >
> > + /*
> > + * currently arm_iommu_create_mapping() takes a max of size_t
> > + * for size param. So check this limit for now.
> > + */
> > + if (size > SIZE_MAX)
> > + return false;
> > +
> > mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
> > if (IS_ERR(mapping)) {
> > pr_warn("Failed to create %llu-byte IOMMU mapping for device
> > %s\n",
> > @@ -2053,6 +2060,9 @@ void arch_setup_dma_ops(struct device *dev, u64
> > dma_base, u64 size,
> > {
> > struct dma_map_ops *dma_ops;
> >
> > + /* limit dma_mask to the lower of the two values */
> > + *dev->dma_mask = min((*dev->dma_mask), (dma_base + size - 1));
> > +
>
> Is there any reason not to do this in of_dma_configure? It seems like
> something everyone could benefit from - I'd cooked up a dodgy workaround
> for the same issue in my arm64 IOMMU code, but handling it generically
> in common code would be much nicer.
I agree. I started something here:
http://article.gmane.org/gmane.linux.kernel/1835096
but I don't remember to have got to a clear conclusion.
--
Catalin
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