From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 16 Jun 2014 16:04:03 +0100 Subject: [RFC PATCH v6 01/20] iommu/arm-smmu: change IOMMU_EXEC to IOMMU_NOEXEC In-Reply-To: <1401987808-23596-2-git-send-email-a.motakis@virtualopensystems.com> References: <1401987808-23596-1-git-send-email-a.motakis@virtualopensystems.com> <1401987808-23596-2-git-send-email-a.motakis@virtualopensystems.com> Message-ID: <20140616150403.GO16758@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jun 05, 2014 at 06:03:09PM +0100, Antonios Motakis wrote: > Exposing the XN flag of the SMMU driver as IOMMU_NOEXEC instead of > IOMMU_EXEC makes it enforceable, since for IOMMUs that don't support > the XN flag pages will always be executable. > > Signed-off-by: Antonios Motakis > --- > drivers/iommu/arm-smmu.c | 2 +- > include/linux/iommu.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 647c3c7..d5a2200 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1294,7 +1294,7 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd, > } > > /* If no access, create a faulting entry to avoid TLB fills */ > - if (prot & IOMMU_EXEC) > + if (!(prot & IOMMU_NOEXEC)) > pteval &= ~ARM_SMMU_PTE_XN; It's probably simpler to change the logic so that we initialise pteval without XN set, then set it if IOMMU_NOEXEC is set (rather than set it by default, then clear it if NOEXEC is not set). Will