Messages in this thread | | | Date | Tue, 27 Jan 2015 10:19:55 -0500 | From | Murali Karicheri <> | Subject | Re: [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size |
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On 01/27/2015 06:34 AM, Catalin Marinas wrote: > 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-karicheri2@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.
Ok Will move this to of_dma_configure().
Murali
> > 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. >
-- Murali Karicheri Linux Kernel, Texas Instruments
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