From: will.deacon@arm.com (Will Deacon)
Date: Fri, 22 Aug 2014 16:22:15 +0100
Subject: [PATCH v3 1/1] iommu/arm-smmu: Do not access non-existing S2CR
 registers
In-Reply-To: <1408403858-16766-1-git-send-email-ohaugan@codeaurora.org>
References: <1408403858-16766-1-git-send-email-ohaugan@codeaurora.org>
Message-ID: <20140822152215.GC17255@arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi Olav,

Some really minor comments, but this looks good.

On Tue, Aug 19, 2014 at 12:17:38AM +0100, Olav Haugan wrote:
> The number of S2CR registers is not properly set when stream
> matching is not supported. Fix this and add check that we do not try to
> access outside of the number of S2CR regisrers.
> 
> Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
> ---
>  drivers/iommu/arm-smmu.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 9fd8754d..a050f7a 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -548,9 +548,16 @@ static int register_smmu_master(struct arm_smmu_device *smmu,
>  	master->of_node			= masterspec->np;
>  	master->cfg.num_streamids	= masterspec->args_count;
>  
> -	for (i = 0; i < master->cfg.num_streamids; ++i)
> +	for (i = 0; i < master->cfg.num_streamids; ++i) {
> +		if (!(smmu->features & ARM_SMMU_FEAT_STREAM_MATCH) &&
> +		     (masterspec->args[i] >= smmu->num_mapping_groups)) {

Can we stick masterspec->args[i] into a loop-local streamid variable,
please?

> +			dev_err(dev,
> +				"stream ID for master device %s greater than maximum allowed (%d)\n",
> +				masterspec->np->name, smmu->num_mapping_groups);
> +			return -ENOSPC;

-ERANGE might be better.

Will