From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/2] iommu/arm-smmu: add support for access-protected mappings
Date: Fri, 19 Sep 2014 23:05:36 +0100 [thread overview]
Message-ID: <20140919220535.GM20773@arm.com> (raw)
In-Reply-To: <1410984969-2340-3-git-send-email-mitchelh@codeaurora.org>
On Wed, Sep 17, 2014 at 09:16:09PM +0100, Mitchel Humpherys wrote:
> ARM SMMUs support memory access control via some bits in the translation
> table descriptor memory attributes. Currently we assume all translations
> are "unprivileged". Add support for privileged mappings, controlled by
> the IOMMU_PRIV prot flag.
>
> Also sneak in a whitespace change for consistency with nearby code.
>
> Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora•org>
> ---
> drivers/iommu/arm-smmu.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index ca18d6d42a..93999ec22c 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1256,10 +1256,11 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd,
> }
>
> if (stage == 1) {
> - pteval |= ARM_SMMU_PTE_AP_UNPRIV | ARM_SMMU_PTE_nG;
> + pteval |= ARM_SMMU_PTE_nG;
> + if (!(prot & IOMMU_PRIV))
> + pteval |= ARM_SMMU_PTE_AP_UNPRIV;
I think this actually makes more sense if we invert the logic, i.e. have
IOMMU_USER as a flag which sets the UNPRIV bit in the pte.
I don't have the spec to hand, but I guess you can't enforce this at
stage-2? If so, do we also need a new IOMMU capability so people don't try
to use this for stage-2 only SMMUs?
Will
next prev parent reply other threads:[~2014-09-19 22:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-17 20:16 [PATCH 0/2] Add access-protected IOMMU mappings Mitchel Humpherys
2014-09-17 20:16 ` [PATCH 1/2] iommu: add IOMMU_PRIV flag for access-protected mappings Mitchel Humpherys
2014-09-17 20:16 ` [PATCH 2/2] iommu/arm-smmu: add support " Mitchel Humpherys
2014-09-19 22:05 ` Will Deacon [this message]
2014-09-22 22:28 ` Mitchel Humpherys
2014-09-24 16:27 ` Will Deacon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140919220535.GM20773@arm.com \
--to=will.deacon@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox