From a44a9791e778d9ccda50d5534028ed4057a9a45b Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 7 Nov 2013 18:47:50 +0000 Subject: iommu/arm-smmu: use mutex instead of spinlock for locking page tables When creating IO mappings, we lazily allocate our page tables using the standard, non-atomic allocator functions. This presents us with a problem, since our page tables are protected with a spinlock. This patch reworks the smmu_domain lock to use a mutex instead of a spinlock. iova_to_phys is then reworked so that it only reads the page tables, and can run in a lockless fashion, leaving the mutex to guard against concurrent mapping threads. Cc: Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu.c | 62 ++++++++++++++++++++---------------------------- 1 file changed, 26 insertions(+), 36 deletions(-) (limited to 'drivers') diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 1abfb5684ab7..6dbcaa4433cd 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -392,7 +392,7 @@ struct arm_smmu_domain { struct arm_smmu_cfg root_cfg; phys_addr_t output_mask; - spinlock_t lock; + struct mutex lock; }; static DEFINE_SPINLOCK(arm_smmu_devices_lock); @@ -900,7 +900,7 @@ static int arm_smmu_domain_init(struct iommu_domain *domain) goto out_free_domain; smmu_domain->root_cfg.pgd = pgd; - spin_lock_init(&smmu_domain->lock); + mutex_init(&smmu_domain->lock); domain->priv = smmu_domain; return 0; @@ -1137,7 +1137,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) * Sanity check the domain. We don't currently support domains * that cross between different SMMU chains. */ - spin_lock(&smmu_domain->lock); + mutex_lock(&smmu_domain->lock); if (!smmu_domain->leaf_smmu) { /* Now that we have a master, we can finalise the domain */ ret = arm_smmu_init_domain_context(domain, dev); @@ -1152,7 +1152,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) dev_name(device_smmu->dev)); goto err_unlock; } - spin_unlock(&smmu_domain->lock); + mutex_unlock(&smmu_domain->lock); /* Looks ok, so add the device to the domain */ master = find_smmu_master(smmu_domain->leaf_smmu, dev->of_node); @@ -1162,7 +1162,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) return arm_smmu_domain_add_master(smmu_domain, master); err_unlock: - spin_unlock(&smmu_domain->lock); + mutex_unlock(&smmu_domain->lock); return ret; } @@ -1394,7 +1394,7 @@ static int arm_smmu_handle_mapping(struct arm_smmu_domain *smmu_domain, if (paddr & ~output_mask) return -ERANGE; - spin_lock(&smmu_domain->lock); + mutex_lock(&smmu_domain->lock); pgd += pgd_index(iova); end = iova + size; do { @@ -1410,7 +1410,7 @@ static int arm_smmu_handle_mapping(struct arm_smmu_domain *smmu_domain, } while (pgd++, iova != end); out_unlock: - spin_unlock(&smmu_domain->lock); + mutex_unlock(&smmu_domain->lock); /* Ensure new page tables are visible to the hardware walker */ if (smmu->features & ARM_SMMU_FEAT_COHERENT_WALK) @@ -1449,44 +1449,34 @@ static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova) { - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; + pgd_t *pgdp, pgd; + pud_t pud; + pmd_t pmd; + pte_t pte; struct arm_smmu_domain *smmu_domain = domain->priv; struct arm_smmu_cfg *root_cfg = &smmu_domain->root_cfg; - struct arm_smmu_device *smmu = root_cfg->smmu; - spin_lock(&smmu_domain->lock); - pgd = root_cfg->pgd; - if (!pgd) - goto err_unlock; + pgdp = root_cfg->pgd; + if (!pgdp) + return 0; - pgd += pgd_index(iova); - if (pgd_none_or_clear_bad(pgd)) - goto err_unlock; + pgd = *(pgdp + pgd_index(iova)); + if (pgd_none(pgd)) + return 0; - pud = pud_offset(pgd, iova); - if (pud_none_or_clear_bad(pud)) - goto err_unlock; + pud = *pud_offset(&pgd, iova); + if (pud_none(pud)) + return 0; - pmd = pmd_offset(pud, iova); - if (pmd_none_or_clear_bad(pmd)) - goto err_unlock; + pmd = *pmd_offset(&pud, iova); + if (pmd_none(pmd)) + return 0; - pte = pmd_page_vaddr(*pmd) + pte_index(iova); + pte = *(pmd_page_vaddr(pmd) + pte_index(iova)); if (pte_none(pte)) - goto err_unlock; - - spin_unlock(&smmu_domain->lock); - return __pfn_to_phys(pte_pfn(*pte)) | (iova & ~PAGE_MASK); + return 0; -err_unlock: - spin_unlock(&smmu_domain->lock); - dev_warn(smmu->dev, - "invalid (corrupt?) page tables detected for iova 0x%llx\n", - (unsigned long long)iova); - return -EINVAL; + return __pfn_to_phys(pte_pfn(pte)) | (iova & ~PAGE_MASK); } static int arm_smmu_domain_has_cap(struct iommu_domain *domain, -- cgit v1.2.3 From 5552ecdbf9fb4f7608c1d7933a8baafcfa1bb337 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 8 Nov 2013 15:08:06 +0000 Subject: iommu/arm-smmu: remove potential NULL dereference on mapping path When handling mapping requests, we dereference the SMMU domain before checking that it is NULL. This patch fixes the issue by removing the check altogether, since we don't actually use the leaf_smmu when creating mappings. Reported-by: Dan Carpenter Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 6dbcaa4433cd..ef77e3dd6dd2 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1423,9 +1423,8 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int flags) { struct arm_smmu_domain *smmu_domain = domain->priv; - struct arm_smmu_device *smmu = smmu_domain->leaf_smmu; - if (!smmu_domain || !smmu) + if (!smmu_domain) return -ENODEV; /* Check for silent address truncation up the SMMU chain. */ -- cgit v1.2.3 From 89a23cde75a7f0b3d8b0c156964eca0c23d2f1eb Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Fri, 15 Nov 2013 09:42:30 +0000 Subject: iommu/arm-smmu: fix error return code in arm_smmu_device_dt_probe() Fix to return -ENODEV instead of 0 when context interrupt number does no match in arm_smmu_device_dt_probe(). Signed-off-by: Wei Yongjun Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers') diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index ef77e3dd6dd2..e46a88700b68 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1852,6 +1852,7 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev) dev_err(dev, "found only %d context interrupt(s) but %d required\n", smmu->num_context_irqs, smmu->num_context_banks); + err = -ENODEV; goto out_put_parent; } -- cgit v1.2.3