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Commit 402575ce authored by Mitchel Humpherys's avatar Mitchel Humpherys Committed by Neeti Desai
Browse files

iommu/arm-smmu: Make arm_smmu_unprepare_pgtable atomic 



Currently, arm_smmu_unprepare_pgtable makes a hypervisor call to
unassign the memory being freed up.  However, this is a sleeping call
and arm_smmu_unprepare_pgtable can be called from atomic context.  Fix
this by making arm_smmu_unprepare_pgtable atomic in a similar manner to
arm_smmu_prepare_pgtable (put the addresses to be unprepared on a list
and unprepare them at the end of unmap).

Change-Id: Ifba40ca3ceb4aaf328a1a570e0ee6c39088075ba
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
parent cdcb5b53

drivers/iommu/arm-smmu.c

+54 −13
Original line number Diff line number Diff line
@@ -432,7 +432,8 @@ enum arm_smmu_domain_stage { 
};



struct arm_smmu_pte_info {

	phys_addr_t phys_addr;

	void *virt_addr;

	size_t size;

	struct list_head entry;

};
@@ -447,6 +448,7 @@ struct arm_smmu_domain { 
	u32				attributes;

	u32				secure_vmid;

	struct list_head		pte_info_list;

	struct list_head		unassign_list;

};



static struct iommu_ops arm_smmu_ops;
@@ -948,7 +950,7 @@ static void arm_smmu_flush_pgtable(void *addr, size_t size, void *cookie) 
}



static void arm_smmu_prepare_pgtable(void *addr, void *cookie);

static void arm_smmu_unprepare_pgtable(void *cookie, void *addr);

static void arm_smmu_unprepare_pgtable(void *cookie, void *addr, size_t size);



static void *arm_smmu_alloc_pages_exact(void *cookie,

					size_t size, gfp_t gfp_mask)
@@ -963,8 +965,8 @@ static void *arm_smmu_alloc_pages_exact(void *cookie, 


static void arm_smmu_free_pages_exact(void *cookie, void *virt, size_t size)

{

	arm_smmu_unprepare_pgtable(cookie, virt);

	free_pages_exact(virt, size);

	arm_smmu_unprepare_pgtable(cookie, virt, size);

	/* unprepare also frees (possibly later), no need to free here */

}



static struct iommu_gather_ops arm_smmu_gather_ops = {
@@ -1450,6 +1452,8 @@ out: 
	return ret;

}



static void arm_smmu_unassign_table(struct arm_smmu_domain *smmu_domain);



static void arm_smmu_destroy_domain_context(struct iommu_domain *domain)

{

	struct arm_smmu_domain *smmu_domain = domain->priv;
@@ -1471,8 +1475,11 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) 
		free_irq(irq, domain);

	}



	if (smmu_domain->pgtbl_ops)

	if (smmu_domain->pgtbl_ops) {

		free_io_pgtable_ops(smmu_domain->pgtbl_ops);

		/* unassign any freed page table memory */

		arm_smmu_unassign_table(smmu_domain);

	}



	arm_smmu_disable_clocks(smmu_domain->smmu);
@@ -1497,6 +1504,7 @@ static int arm_smmu_domain_init(struct iommu_domain *domain) 
	/* disable coherent htw by default */

	smmu_domain->attributes = (1 << DOMAIN_ATTR_COHERENT_HTW_DISABLE);

	INIT_LIST_HEAD(&smmu_domain->pte_info_list);

	INIT_LIST_HEAD(&smmu_domain->unassign_list);

	smmu_domain->cfg.cbndx = INVALID_CBNDX;

	smmu_domain->cfg.irptndx = INVALID_IRPTNDX;

	smmu_domain->cfg.asid = INVALID_ASID;
@@ -1916,8 +1924,9 @@ static void arm_smmu_assign_table(struct arm_smmu_domain *smmu_domain) 


	list_for_each_entry(pte_info, &smmu_domain->pte_info_list,

								entry) {

		ret = hyp_assign_phys(pte_info->phys_addr, PAGE_SIZE,

				&source_vmid, 1, dest_vmids, dest_perms, 2);

		ret = hyp_assign_phys(virt_to_phys(pte_info->virt_addr),

				      PAGE_SIZE, &source_vmid, 1,

				      dest_vmids, dest_perms, 2);

		if (WARN_ON(ret))

			break;

	}
@@ -1929,20 +1938,50 @@ static void arm_smmu_assign_table(struct arm_smmu_domain *smmu_domain) 
	}

}



static void arm_smmu_unprepare_pgtable(void *cookie, void *addr)

static void arm_smmu_unassign_table(struct arm_smmu_domain *smmu_domain)

{

	struct arm_smmu_domain *smmu_domain = cookie;

	int ret;

	int dest_vmids = VMID_HLOS;

	int dest_perms = PERM_READ | PERM_WRITE | PERM_EXEC;

	int source_vmlist[2] = {VMID_HLOS, smmu_domain->secure_vmid};

	struct arm_smmu_pte_info *pte_info, *temp;



	if (smmu_domain->secure_vmid == VMID_INVAL)

		return;



	ret = hyp_assign_phys((phys_addr_t)virt_to_phys(addr), PAGE_SIZE,

			source_vmlist, 2, &dest_vmids, &dest_perms, 1);

	WARN_ON(ret);

	list_for_each_entry(pte_info, &smmu_domain->unassign_list, entry) {

		ret = hyp_assign_phys(virt_to_phys(pte_info->virt_addr),

				      PAGE_SIZE, source_vmlist, 2,

				      &dest_vmids, &dest_perms, 1);

		if (WARN_ON(ret))

			break;

		free_pages_exact(pte_info->virt_addr, pte_info->size);

	}



	list_for_each_entry_safe(pte_info, temp, &smmu_domain->unassign_list,

				 entry) {

		list_del(&pte_info->entry);

		kfree(pte_info);

	}

}



static void arm_smmu_unprepare_pgtable(void *cookie, void *addr, size_t size)

{

	struct arm_smmu_domain *smmu_domain = cookie;

	struct arm_smmu_pte_info *pte_info;



	if (smmu_domain->secure_vmid == VMID_INVAL) {

		free_pages_exact(addr, size);

		return;

	}



	pte_info = kzalloc(sizeof(struct arm_smmu_pte_info), GFP_ATOMIC);

	if (!pte_info)

		return;



	pte_info->virt_addr = addr;

	pte_info->size = size;

	list_add_tail(&pte_info->entry, &smmu_domain->unassign_list);

}



static void arm_smmu_prepare_pgtable(void *addr, void *cookie)
@@ -1956,7 +1995,7 @@ static void arm_smmu_prepare_pgtable(void *addr, void *cookie) 
	pte_info = kzalloc(sizeof(struct arm_smmu_pte_info), GFP_ATOMIC);

	if (!pte_info)

		return;

	pte_info->phys_addr = (phys_addr_t)virt_to_phys(addr);

	pte_info->virt_addr = addr;

	list_add_tail(&pte_info->entry, &smmu_domain->pte_info_list);

}
@@ -2043,6 +2082,8 @@ static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, 
	 * memory here as well.

	 */

	arm_smmu_assign_table(smmu_domain);

	/* Also unassign any pages that were free'd during unmap */

	arm_smmu_unassign_table(smmu_domain);



	if (atomic_ctx) {

		arm_smmu_disable_clocks_atomic(smmu_domain->smmu);