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From: Catalin Marinas <catalin.marinas@arm.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>
Subject: Re: [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size
Date: Tue, 27 Jan 2015 11:34:16 +0000	[thread overview]
Message-ID: <20150127113416.GB3226@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <54C772A0.2000203@arm.com>

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.

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

  reply	other threads:[~2015-01-27 11:34 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-23 22:32 [PATCH v4 0/6] PCI: get DMA configuration from parent device Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Murali Karicheri
2015-01-25 13:32   ` Laurent Pinchart
2015-01-26 18:49     ` Murali Karicheri
2015-01-28 11:33       ` Will Deacon
2015-01-28 12:23         ` Laurent Pinchart
2015-01-28 12:29           ` Will Deacon
2015-01-28 13:15             ` Laurent Pinchart
2015-01-28 13:32               ` Will Deacon
2015-01-28 15:21                 ` Murali Karicheri
2015-01-28 23:32                 ` Laurent Pinchart
2015-01-29 14:59                   ` Murali Karicheri
2015-01-29 16:49                   ` Rob Herring
2015-01-30  0:24                     ` Laurent Pinchart
2015-01-30 15:23                       ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 2/6] of: move of_dma_configure() to device.c to help re-use Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 3/6] of: fix size when dma-range is not used Murali Karicheri
2015-01-27 11:27   ` Robin Murphy
2015-01-27 15:44     ` Murali Karicheri
2015-01-27 18:55     ` Murali Karicheri
2015-01-28 11:05       ` Catalin Marinas
2015-01-28 15:45         ` Rob Herring
2015-01-28 17:23           ` Catalin Marinas
2015-01-28 17:34           ` Murali Karicheri
2015-01-28 15:55         ` Robin Murphy
2015-01-28 17:30           ` Catalin Marinas
2015-01-30 18:06             ` Murali Karicheri
2015-02-02 12:18               ` Catalin Marinas
2015-02-02 16:10                 ` Murali Karicheri
2015-02-05 21:42                 ` Murali Karicheri
2015-02-05 22:44                   ` Catalin Marinas
2015-01-23 22:32 ` [PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma configuration Murali Karicheri
2015-01-23 23:41   ` Bjorn Helgaas
2015-01-26 23:25     ` Murali Karicheri
2015-01-26 23:59       ` Bjorn Helgaas
2015-01-27 18:14         ` Murali Karicheri
2015-01-27 18:42           ` Bjorn Helgaas
2015-01-27 18:45             ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 5/6] PCI: update dma configuration from DT Murali Karicheri
2015-01-23 23:27   ` Bjorn Helgaas
2015-01-26 23:28     ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size Murali Karicheri
2015-01-27 11:12   ` Robin Murphy
2015-01-27 11:34     ` Catalin Marinas [this message]
2015-01-27 15:19       ` Murali Karicheri

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