linux-kernel - Re: [PATCH v5 2/2] iommu/exynos: Add iommu driver for Exynos Platforms

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 14 Oct 2011 16:17:14 +0200
From:	"Roedel, Joerg" <Joerg.Roedel@....com>
To:	KyongHo Cho <pullip.cho@...sung.com>
CC:	'Linux ARM Kernel' <linux-arm-kernel@...ts.infradead.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	'Russell King' <rmk+kernel@....linux.org.uk>,
	'Ohad Ben-Cohen' <ohad@...ery.com>,
	'Sanghyun Lee' <sanghyun75.lee@...sung.com>,
	"younglak1004.kim@...sung.com" <younglak1004.kim@...sung.com>,
	'Kukjin Kim' <kgene.kim@...sung.com>
Subject: Re: [PATCH v5 2/2] iommu/exynos: Add iommu driver for Exynos
 Platforms

On Thu, Oct 13, 2011 at 04:13:23AM -0400, KyongHo Cho wrote:
> +struct exynos_iommu_domain {
> +       struct device *dev;
> +       unsigned long *pgtable;
> +       spinlock_t lock;
> +       spinlock_t pgtablelock;
> +};

Can you please add comments to document what these spinlocks protect?

> +static int exynos_iommu_attach_device(struct iommu_domain *domain,
> +                                  struct device *dev)
> +{
> +       struct exynos_iommu_domain *priv = domain->priv;
> +       int ret;
> +
> +       spin_lock(&priv->lock);
> +
> +       priv->dev = dev;
> +
> +       spin_unlock(&priv->lock);
> +
> +       ret = exynos_iommu_enable(domain);
> +
> +       return ret;
> +}
> +
> +static void exynos_iommu_detach_device(struct iommu_domain *domain,
> +                                   struct device *dev)
> +{
> +       struct exynos_iommu_domain *priv = domain->priv;
> +
> +       spin_lock(&priv->lock);
> +
> +       if (priv->dev == dev) {
> +               priv->dev = NULL;
> +
> +               spin_unlock(&priv->lock);
> +
> +               exynos_iommu_disable(domain);
> +       } else {
> +               spin_unlock(&priv->lock);
> +       }
> +}

That looks weird. As I read this code there is a 1-1 mapping between a
device and a domain. This breaks semantics of the iommu-api where a
domain can contain multiple devices.


	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/