drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Implementation of the IOMMU SVA API for the ARM SMMUv3
  */

 #include <linux/mm.h>
 #include <linux/mmu_context.h>
 #include <linux/mmu_notifier.h>
 #include <linux/slab.h>

 #include "arm-smmu-v3.h"
 #include "../../iommu-sva-lib.h"
 #include "../../io-pgtable-arm.h"

 struct arm_smmu_mmu_notifier {
 	struct mmu_notifier		mn;
 	struct arm_smmu_ctx_desc	*cd;
 	bool				cleared;
 	refcount_t			refs;
 	struct list_head		list;
 	struct arm_smmu_domain		*domain;
 };

 #define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn)

 struct arm_smmu_bond {
 	struct iommu_sva		sva;
 	struct mm_struct		*mm;
 	struct arm_smmu_mmu_notifier	*smmu_mn;
 	struct list_head		list;
 	refcount_t			refs;
 };

 #define sva_to_bond(handle) \
 	container_of(handle, struct arm_smmu_bond, sva)

 static DEFINE_MUTEX(sva_lock);

 /*
  * Check if the CPU ASID is available on the SMMU side. If a private context
  * descriptor is using it, try to replace it.
  */
 static struct arm_smmu_ctx_desc *
 arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 {
 	int ret;
 	u32 new_asid;
 	struct arm_smmu_ctx_desc *cd;
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_domain *smmu_domain;

 	cd = xa_load(&arm_smmu_asid_xa, asid);
 	if (!cd)
 		return NULL;

 	if (cd->mm) {
 		if (WARN_ON(cd->mm != mm))
 			return ERR_PTR(-EINVAL);
 		/* All devices bound to this mm use the same cd struct. */
 		refcount_inc(&cd->refs);
 		return cd;
 	}

 	smmu_domain = container_of(cd, struct arm_smmu_domain, s1_cfg.cd);
 	smmu = smmu_domain->smmu;

 	ret = xa_alloc(&arm_smmu_asid_xa, &new_asid, cd,
 		       XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
 	if (ret)
 		return ERR_PTR(-ENOSPC);
 	/*
 	 * Race with unmap: TLB invalidations will start targeting the new ASID,
 	 * which isn't assigned yet. We'll do an invalidate-all on the old ASID
 	 * later, so it doesn't matter.
 	 */
 	cd->asid = new_asid;
 	/*
 	 * Update ASID and invalidate CD in all associated masters. There will
 	 * be some overlap between use of both ASIDs, until we invalidate the
 	 * TLB.
 	 */
 	arm_smmu_write_ctx_desc(smmu_domain, 0, cd);

 	/* Invalidate TLB entries previously associated with that context */
 	arm_smmu_tlb_inv_asid(smmu, asid);

 	xa_erase(&arm_smmu_asid_xa, asid);
 	return NULL;
 }

 static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
 {
 	u16 asid;
 	int err = 0;
 	u64 tcr, par, reg;
 	struct arm_smmu_ctx_desc *cd;
 	struct arm_smmu_ctx_desc *ret = NULL;

 	asid = arm64_mm_context_get(mm);
 	if (!asid)
 		return ERR_PTR(-ESRCH);

 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
 	if (!cd) {
 		err = -ENOMEM;
 		goto out_put_context;
 	}

 	refcount_set(&cd->refs, 1);

 	mutex_lock(&arm_smmu_asid_lock);
 	ret = arm_smmu_share_asid(mm, asid);
 	if (ret) {
 		mutex_unlock(&arm_smmu_asid_lock);
 		goto out_free_cd;
 	}

 	err = xa_insert(&arm_smmu_asid_xa, asid, cd, GFP_KERNEL);
 	mutex_unlock(&arm_smmu_asid_lock);

 	if (err)
 		goto out_free_asid;

 	tcr = FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, 64ULL - vabits_actual) |
 	      FIELD_PREP(CTXDESC_CD_0_TCR_IRGN0, ARM_LPAE_TCR_RGN_WBWA) |
 	      FIELD_PREP(CTXDESC_CD_0_TCR_ORGN0, ARM_LPAE_TCR_RGN_WBWA) |
 	      FIELD_PREP(CTXDESC_CD_0_TCR_SH0, ARM_LPAE_TCR_SH_IS) |
 	      CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;

 	switch (PAGE_SIZE) {
 	case SZ_4K:
 		tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_4K);
 		break;
 	case SZ_16K:
 		tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_16K);
 		break;
 	case SZ_64K:
 		tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_64K);
 		break;
 	default:
 		WARN_ON(1);
 		err = -EINVAL;
 		goto out_free_asid;
 	}

 	reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	par = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_PARANGE_SHIFT);
 	tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_IPS, par);

 	cd->ttbr = virt_to_phys(mm->pgd);
 	cd->tcr = tcr;
 	/*
 	 * MAIR value is pretty much constant and global, so we can just get it
 	 * from the current CPU register
 	 */
 	cd->mair = read_sysreg(mair_el1);
 	cd->asid = asid;
 	cd->mm = mm;

 	return cd;

 out_free_asid:
 	arm_smmu_free_asid(cd);
 out_free_cd:
 	kfree(cd);
 out_put_context:
 	arm64_mm_context_put(mm);
 	return err < 0 ? ERR_PTR(err) : ret;
 }

 static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 {
 	if (arm_smmu_free_asid(cd)) {
 		/* Unpin ASID */
 		arm64_mm_context_put(cd->mm);
 		kfree(cd);
 	}
 }

 static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
 					 struct mm_struct *mm,
 					 unsigned long start, unsigned long end)
 {
 	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
 	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
 	size_t size = end - start + 1;

 	if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM))
 		arm_smmu_tlb_inv_range_asid(start, size, smmu_mn->cd->asid,
 					    PAGE_SIZE, false, smmu_domain);
 	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, start, size);
 }

 static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 {
 	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
 	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;

 	mutex_lock(&sva_lock);
 	if (smmu_mn->cleared) {
 		mutex_unlock(&sva_lock);
 		return;
 	}

 	/*
 	 * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
 	 * but disable translation.
 	 */
 	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);

 	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
 	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);

 	smmu_mn->cleared = true;
 	mutex_unlock(&sva_lock);
 }

 static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
 {
 	kfree(mn_to_smmu(mn));
 }

 static const struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
 	.invalidate_range	= arm_smmu_mm_invalidate_range,
 	.release		= arm_smmu_mm_release,
 	.free_notifier		= arm_smmu_mmu_notifier_free,
 };

 /* Allocate or get existing MMU notifier for this {domain, mm} pair */
 static struct arm_smmu_mmu_notifier *
 arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
 			  struct mm_struct *mm)
 {
 	int ret;
 	struct arm_smmu_ctx_desc *cd;
 	struct arm_smmu_mmu_notifier *smmu_mn;

 	list_for_each_entry(smmu_mn, &smmu_domain->mmu_notifiers, list) {
 		if (smmu_mn->mn.mm == mm) {
 			refcount_inc(&smmu_mn->refs);
 			return smmu_mn;
 		}
 	}

 	cd = arm_smmu_alloc_shared_cd(mm);
 	if (IS_ERR(cd))
 		return ERR_CAST(cd);

 	smmu_mn = kzalloc(sizeof(*smmu_mn), GFP_KERNEL);
 	if (!smmu_mn) {
 		ret = -ENOMEM;
 		goto err_free_cd;
 	}

 	refcount_set(&smmu_mn->refs, 1);
 	smmu_mn->cd = cd;
 	smmu_mn->domain = smmu_domain;
 	smmu_mn->mn.ops = &arm_smmu_mmu_notifier_ops;

 	ret = mmu_notifier_register(&smmu_mn->mn, mm);
 	if (ret) {
 		kfree(smmu_mn);
 		goto err_free_cd;
 	}

 	ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
 	if (ret)
 		goto err_put_notifier;

 	list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers);
 	return smmu_mn;

 err_put_notifier:
 	/* Frees smmu_mn */
 	mmu_notifier_put(&smmu_mn->mn);
 err_free_cd:
 	arm_smmu_free_shared_cd(cd);
 	return ERR_PTR(ret);
 }

 static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 {
 	struct mm_struct *mm = smmu_mn->mn.mm;
 	struct arm_smmu_ctx_desc *cd = smmu_mn->cd;
 	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;

 	if (!refcount_dec_and_test(&smmu_mn->refs))
 		return;

 	list_del(&smmu_mn->list);
 	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);

 	/*
 	 * If we went through clear(), we've already invalidated, and no
 	 * new TLB entry can have been formed.
 	 */
 	if (!smmu_mn->cleared) {
 		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
 		arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
 	}

 	/* Frees smmu_mn */
 	mmu_notifier_put(&smmu_mn->mn);
 	arm_smmu_free_shared_cd(cd);
 }

 static struct iommu_sva *
 __arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
 {
 	int ret;
 	struct arm_smmu_bond *bond;
 	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

 	if (!master || !master->sva_enabled)
 		return ERR_PTR(-ENODEV);

 	/* If bind() was already called for this {dev, mm} pair, reuse it. */
 	list_for_each_entry(bond, &master->bonds, list) {
 		if (bond->mm == mm) {
 			refcount_inc(&bond->refs);
 			return &bond->sva;
 		}
 	}

 	bond = kzalloc(sizeof(*bond), GFP_KERNEL);
 	if (!bond)
 		return ERR_PTR(-ENOMEM);

 	/* Allocate a PASID for this mm if necessary */
 	ret = iommu_sva_alloc_pasid(mm, 1, (1U << master->ssid_bits) - 1);
 	if (ret)
 		goto err_free_bond;

 	bond->mm = mm;
 	bond->sva.dev = dev;
 	refcount_set(&bond->refs, 1);

 	bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm);
 	if (IS_ERR(bond->smmu_mn)) {
 		ret = PTR_ERR(bond->smmu_mn);
 		goto err_free_pasid;
 	}

 	list_add(&bond->list, &master->bonds);
 	return &bond->sva;

 err_free_pasid:
 	iommu_sva_free_pasid(mm);
 err_free_bond:
 	kfree(bond);
 	return ERR_PTR(ret);
 }

 struct iommu_sva *
 arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
 {
 	struct iommu_sva *handle;
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

 	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
 		return ERR_PTR(-EINVAL);

 	mutex_lock(&sva_lock);
 	handle = __arm_smmu_sva_bind(dev, mm);
 	mutex_unlock(&sva_lock);
 	return handle;
 }

 void arm_smmu_sva_unbind(struct iommu_sva *handle)
 {
 	struct arm_smmu_bond *bond = sva_to_bond(handle);

 	mutex_lock(&sva_lock);
 	if (refcount_dec_and_test(&bond->refs)) {
 		list_del(&bond->list);
 		arm_smmu_mmu_notifier_put(bond->smmu_mn);
 		iommu_sva_free_pasid(bond->mm);
 		kfree(bond);
 	}
 	mutex_unlock(&sva_lock);
 }

 u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
 {
 	struct arm_smmu_bond *bond = sva_to_bond(handle);

 	return bond->mm->pasid;
 }

 bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
 {
 	unsigned long reg, fld;
 	unsigned long oas;
 	unsigned long asid_bits;
 	u32 feat_mask = ARM_SMMU_FEAT_COHERENCY;

 	if (vabits_actual == 52)
 		feat_mask |= ARM_SMMU_FEAT_VAX;

 	if ((smmu->features & feat_mask) != feat_mask)
 		return false;

 	if (!(smmu->pgsize_bitmap & PAGE_SIZE))
 		return false;

 	/*
 	 * Get the smallest PA size of all CPUs (sanitized by cpufeature). We're
 	 * not even pretending to support AArch32 here. Abort if the MMU outputs
 	 * addresses larger than what we support.
 	 */
 	reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	fld = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_PARANGE_SHIFT);
 	oas = id_aa64mmfr0_parange_to_phys_shift(fld);
 	if (smmu->oas < oas)
 		return false;

 	/* We can support bigger ASIDs than the CPU, but not smaller */
 	fld = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_ASID_SHIFT);
 	asid_bits = fld ? 16 : 8;
 	if (smmu->asid_bits < asid_bits)
 		return false;

 	/*
 	 * See max_pinned_asids in arch/arm64/mm/context.c. The following is
 	 * generally the maximum number of bindable processes.
 	 */
 	if (arm64_kernel_unmapped_at_el0())
 		asid_bits--;
 	dev_dbg(smmu->dev, "%d shared contexts\n", (1 << asid_bits) -
 		num_possible_cpus() - 2);

 	return true;
 }

 bool arm_smmu_master_iopf_supported(struct arm_smmu_master *master)
 {
 	/* We're not keeping track of SIDs in fault events */
 	if (master->num_streams != 1)
 		return false;

 	return master->stall_enabled;
 }

 bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
 {
 	if (!(master->smmu->features & ARM_SMMU_FEAT_SVA))
 		return false;

 	/* SSID support is mandatory for the moment */
 	return master->ssid_bits;
 }

 bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
 {
 	bool enabled;

 	mutex_lock(&sva_lock);
 	enabled = master->sva_enabled;
 	mutex_unlock(&sva_lock);
 	return enabled;
 }

 static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
 {
 	int ret;
 	struct device *dev = master->dev;

 	/*
 	 * Drivers for devices supporting PRI or stall should enable IOPF first.
 	 * Others have device-specific fault handlers and don't need IOPF.
 	 */
 	if (!arm_smmu_master_iopf_supported(master))
 		return 0;

 	if (!master->iopf_enabled)
 		return -EINVAL;

 	ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
 	if (ret)
 		return ret;

 	ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
 	if (ret) {
 		iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
 		return ret;
 	}
 	return 0;
 }

 static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
 {
 	struct device *dev = master->dev;

 	if (!master->iopf_enabled)
 		return;

 	iommu_unregister_device_fault_handler(dev);
 	iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
 }

 int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
 {
 	int ret;

 	mutex_lock(&sva_lock);
 	ret = arm_smmu_master_sva_enable_iopf(master);
 	if (!ret)
 		master->sva_enabled = true;
 	mutex_unlock(&sva_lock);

 	return ret;
 }

 int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
 {
 	mutex_lock(&sva_lock);
 	if (!list_empty(&master->bonds)) {
 		dev_err(master->dev, "cannot disable SVA, device is bound\n");
 		mutex_unlock(&sva_lock);
 		return -EBUSY;
 	}
 	arm_smmu_master_sva_disable_iopf(master);
 	master->sva_enabled = false;
 	mutex_unlock(&sva_lock);

 	return 0;
 }

 void arm_smmu_sva_notifier_synchronize(void)
 {
 	/*
 	 * Some MMU notifiers may still be waiting to be freed, using
 	 * arm_smmu_mmu_notifier_free(). Wait for them.
 	 */
 	mmu_notifier_synchronize();
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Implementation of the IOMMU SVA API for the ARM SMMUv3
	*/

	#include <linux/mm.h>
	#include <linux/mmu_context.h>
	#include <linux/mmu_notifier.h>
	#include <linux/slab.h>

	#include "arm-smmu-v3.h"
	#include "../../iommu-sva-lib.h"
	#include "../../io-pgtable-arm.h"

	struct arm_smmu_mmu_notifier {
	struct mmu_notifier mn;
	struct arm_smmu_ctx_desc *cd;
	bool cleared;
	refcount_t refs;
	struct list_head list;
	struct arm_smmu_domain *domain;
	};

	#define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn)

	struct arm_smmu_bond {
	struct iommu_sva sva;
	struct mm_struct *mm;
	struct arm_smmu_mmu_notifier *smmu_mn;
	struct list_head list;
	refcount_t refs;
	};

	#define sva_to_bond(handle) \
	container_of(handle, struct arm_smmu_bond, sva)

	static DEFINE_MUTEX(sva_lock);

	/*
	* Check if the CPU ASID is available on the SMMU side. If a private context
	* descriptor is using it, try to replace it.
	*/
	static struct arm_smmu_ctx_desc *
	arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
	{
	int ret;
	u32 new_asid;
	struct arm_smmu_ctx_desc *cd;
	struct arm_smmu_device *smmu;
	struct arm_smmu_domain *smmu_domain;

	cd = xa_load(&arm_smmu_asid_xa, asid);
	if (!cd)
	return NULL;

	if (cd->mm) {
	if (WARN_ON(cd->mm != mm))
	return ERR_PTR(-EINVAL);
	/* All devices bound to this mm use the same cd struct. */
	refcount_inc(&cd->refs);
	return cd;
	}

	smmu_domain = container_of(cd, struct arm_smmu_domain, s1_cfg.cd);
	smmu = smmu_domain->smmu;

	ret = xa_alloc(&arm_smmu_asid_xa, &new_asid, cd,
	XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
	if (ret)
	return ERR_PTR(-ENOSPC);
	/*
	* Race with unmap: TLB invalidations will start targeting the new ASID,
	* which isn't assigned yet. We'll do an invalidate-all on the old ASID
	* later, so it doesn't matter.
	*/
	cd->asid = new_asid;
	/*
	* Update ASID and invalidate CD in all associated masters. There will
	* be some overlap between use of both ASIDs, until we invalidate the
	* TLB.
	*/
	arm_smmu_write_ctx_desc(smmu_domain, 0, cd);

	/* Invalidate TLB entries previously associated with that context */
	arm_smmu_tlb_inv_asid(smmu, asid);

	xa_erase(&arm_smmu_asid_xa, asid);
	return NULL;
	}

	static struct arm_smmu_ctx_desc arm_smmu_alloc_shared_cd(struct mm_struct mm)
	{
	u16 asid;
	int err = 0;
	u64 tcr, par, reg;
	struct arm_smmu_ctx_desc *cd;
	struct arm_smmu_ctx_desc *ret = NULL;

	asid = arm64_mm_context_get(mm);
	if (!asid)
	return ERR_PTR(-ESRCH);

	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
	if (!cd) {
	err = -ENOMEM;
	goto out_put_context;
	}

	refcount_set(&cd->refs, 1);

	mutex_lock(&arm_smmu_asid_lock);
	ret = arm_smmu_share_asid(mm, asid);
	if (ret) {
	mutex_unlock(&arm_smmu_asid_lock);
	goto out_free_cd;
	}

	err = xa_insert(&arm_smmu_asid_xa, asid, cd, GFP_KERNEL);
	mutex_unlock(&arm_smmu_asid_lock);

	if (err)
	goto out_free_asid;

	tcr = FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, 64ULL - vabits_actual) \|
	FIELD_PREP(CTXDESC_CD_0_TCR_IRGN0, ARM_LPAE_TCR_RGN_WBWA) \|
	FIELD_PREP(CTXDESC_CD_0_TCR_ORGN0, ARM_LPAE_TCR_RGN_WBWA) \|
	FIELD_PREP(CTXDESC_CD_0_TCR_SH0, ARM_LPAE_TCR_SH_IS) \|
	CTXDESC_CD_0_TCR_EPD1 \| CTXDESC_CD_0_AA64;

	switch (PAGE_SIZE) {
	case SZ_4K:
	tcr \|= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_4K);
	break;
	case SZ_16K:
	tcr \|= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_16K);
	break;
	case SZ_64K:
	tcr \|= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_64K);
	break;
	default:
	WARN_ON(1);
	err = -EINVAL;
	goto out_free_asid;
	}

	reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
	par = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_PARANGE_SHIFT);
	tcr \|= FIELD_PREP(CTXDESC_CD_0_TCR_IPS, par);

	cd->ttbr = virt_to_phys(mm->pgd);
	cd->tcr = tcr;
	/*
	* MAIR value is pretty much constant and global, so we can just get it
	* from the current CPU register
	*/
	cd->mair = read_sysreg(mair_el1);
	cd->asid = asid;
	cd->mm = mm;

	return cd;

	out_free_asid:
	arm_smmu_free_asid(cd);
	out_free_cd:
	kfree(cd);
	out_put_context:
	arm64_mm_context_put(mm);
	return err < 0 ? ERR_PTR(err) : ret;
	}

	static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
	{
	if (arm_smmu_free_asid(cd)) {
	/* Unpin ASID */
	arm64_mm_context_put(cd->mm);
	kfree(cd);
	}
	}

	static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
	struct mm_struct *mm,
	unsigned long start, unsigned long end)
	{
	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
	size_t size = end - start + 1;

	if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM))
	arm_smmu_tlb_inv_range_asid(start, size, smmu_mn->cd->asid,
	PAGE_SIZE, false, smmu_domain);
	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, start, size);
	}

	static void arm_smmu_mm_release(struct mmu_notifier mn, struct mm_struct mm)
	{
	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;

	mutex_lock(&sva_lock);
	if (smmu_mn->cleared) {
	mutex_unlock(&sva_lock);
	return;
	}

	/*
	* DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
	* but disable translation.
	*/
	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);

	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);

	smmu_mn->cleared = true;
	mutex_unlock(&sva_lock);
	}

	static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
	{
	kfree(mn_to_smmu(mn));
	}

	static const struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
	.invalidate_range = arm_smmu_mm_invalidate_range,
	.release = arm_smmu_mm_release,
	.free_notifier = arm_smmu_mmu_notifier_free,
	};

	/* Allocate or get existing MMU notifier for this {domain, mm} pair */
	static struct arm_smmu_mmu_notifier *
	arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
	struct mm_struct *mm)
	{
	int ret;
	struct arm_smmu_ctx_desc *cd;
	struct arm_smmu_mmu_notifier *smmu_mn;

	list_for_each_entry(smmu_mn, &smmu_domain->mmu_notifiers, list) {
	if (smmu_mn->mn.mm == mm) {
	refcount_inc(&smmu_mn->refs);
	return smmu_mn;
	}
	}

	cd = arm_smmu_alloc_shared_cd(mm);
	if (IS_ERR(cd))
	return ERR_CAST(cd);

	smmu_mn = kzalloc(sizeof(*smmu_mn), GFP_KERNEL);
	if (!smmu_mn) {
	ret = -ENOMEM;
	goto err_free_cd;
	}

	refcount_set(&smmu_mn->refs, 1);
	smmu_mn->cd = cd;
	smmu_mn->domain = smmu_domain;
	smmu_mn->mn.ops = &arm_smmu_mmu_notifier_ops;

	ret = mmu_notifier_register(&smmu_mn->mn, mm);
	if (ret) {
	kfree(smmu_mn);
	goto err_free_cd;
	}

	ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
	if (ret)
	goto err_put_notifier;

	list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers);
	return smmu_mn;

	err_put_notifier:
	/* Frees smmu_mn */
	mmu_notifier_put(&smmu_mn->mn);
	err_free_cd:
	arm_smmu_free_shared_cd(cd);
	return ERR_PTR(ret);
	}

	static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
	{
	struct mm_struct *mm = smmu_mn->mn.mm;
	struct arm_smmu_ctx_desc *cd = smmu_mn->cd;
	struct arm_smmu_domain *smmu_domain = smmu_mn->domain;

	if (!refcount_dec_and_test(&smmu_mn->refs))
	return;

	list_del(&smmu_mn->list);
	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);

	/*
	* If we went through clear(), we've already invalidated, and no
	* new TLB entry can have been formed.
	*/
	if (!smmu_mn->cleared) {
	arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
	}

	/* Frees smmu_mn */
	mmu_notifier_put(&smmu_mn->mn);
	arm_smmu_free_shared_cd(cd);
	}

	static struct iommu_sva *
	__arm_smmu_sva_bind(struct device dev, struct mm_struct mm)
	{
	int ret;
	struct arm_smmu_bond *bond;
	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

	if (!master \|\| !master->sva_enabled)
	return ERR_PTR(-ENODEV);

	/* If bind() was already called for this {dev, mm} pair, reuse it. */
	list_for_each_entry(bond, &master->bonds, list) {
	if (bond->mm == mm) {
	refcount_inc(&bond->refs);
	return &bond->sva;
	}
	}

	bond = kzalloc(sizeof(*bond), GFP_KERNEL);
	if (!bond)
	return ERR_PTR(-ENOMEM);

	/* Allocate a PASID for this mm if necessary */
	ret = iommu_sva_alloc_pasid(mm, 1, (1U << master->ssid_bits) - 1);
	if (ret)
	goto err_free_bond;

	bond->mm = mm;
	bond->sva.dev = dev;
	refcount_set(&bond->refs, 1);

	bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm);
	if (IS_ERR(bond->smmu_mn)) {
	ret = PTR_ERR(bond->smmu_mn);
	goto err_free_pasid;
	}

	list_add(&bond->list, &master->bonds);
	return &bond->sva;

	err_free_pasid:
	iommu_sva_free_pasid(mm);
	err_free_bond:
	kfree(bond);
	return ERR_PTR(ret);
	}

	struct iommu_sva *
	arm_smmu_sva_bind(struct device dev, struct mm_struct mm, void *drvdata)
	{
	struct iommu_sva *handle;
	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
	return ERR_PTR(-EINVAL);

	mutex_lock(&sva_lock);
	handle = __arm_smmu_sva_bind(dev, mm);
	mutex_unlock(&sva_lock);
	return handle;
	}

	void arm_smmu_sva_unbind(struct iommu_sva *handle)
	{
	struct arm_smmu_bond *bond = sva_to_bond(handle);

	mutex_lock(&sva_lock);
	if (refcount_dec_and_test(&bond->refs)) {
	list_del(&bond->list);
	arm_smmu_mmu_notifier_put(bond->smmu_mn);
	iommu_sva_free_pasid(bond->mm);
	kfree(bond);
	}
	mutex_unlock(&sva_lock);
	}

	u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
	{
	struct arm_smmu_bond *bond = sva_to_bond(handle);

	return bond->mm->pasid;
	}

	bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
	{
	unsigned long reg, fld;
	unsigned long oas;
	unsigned long asid_bits;
	u32 feat_mask = ARM_SMMU_FEAT_COHERENCY;

	if (vabits_actual == 52)
	feat_mask \|= ARM_SMMU_FEAT_VAX;

	if ((smmu->features & feat_mask) != feat_mask)
	return false;

	if (!(smmu->pgsize_bitmap & PAGE_SIZE))
	return false;

	/*
	* Get the smallest PA size of all CPUs (sanitized by cpufeature). We're
	* not even pretending to support AArch32 here. Abort if the MMU outputs
	* addresses larger than what we support.
	*/
	reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
	fld = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_PARANGE_SHIFT);
	oas = id_aa64mmfr0_parange_to_phys_shift(fld);
	if (smmu->oas < oas)
	return false;

	/* We can support bigger ASIDs than the CPU, but not smaller */
	fld = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_ASID_SHIFT);
	asid_bits = fld ? 16 : 8;
	if (smmu->asid_bits < asid_bits)
	return false;

	/*
	* See max_pinned_asids in arch/arm64/mm/context.c. The following is
	* generally the maximum number of bindable processes.
	*/
	if (arm64_kernel_unmapped_at_el0())
	asid_bits--;
	dev_dbg(smmu->dev, "%d shared contexts\n", (1 << asid_bits) -
	num_possible_cpus() - 2);

	return true;
	}

	bool arm_smmu_master_iopf_supported(struct arm_smmu_master *master)
	{
	/* We're not keeping track of SIDs in fault events */
	if (master->num_streams != 1)
	return false;

	return master->stall_enabled;
	}

	bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
	{
	if (!(master->smmu->features & ARM_SMMU_FEAT_SVA))
	return false;

	/* SSID support is mandatory for the moment */
	return master->ssid_bits;
	}

	bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
	{
	bool enabled;

	mutex_lock(&sva_lock);
	enabled = master->sva_enabled;
	mutex_unlock(&sva_lock);
	return enabled;
	}

	static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
	{
	int ret;
	struct device *dev = master->dev;

	/*
	* Drivers for devices supporting PRI or stall should enable IOPF first.
	* Others have device-specific fault handlers and don't need IOPF.
	*/
	if (!arm_smmu_master_iopf_supported(master))
	return 0;

	if (!master->iopf_enabled)
	return -EINVAL;

	ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
	if (ret)
	return ret;

	ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
	if (ret) {
	iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
	return ret;
	}
	return 0;
	}

	static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
	{
	struct device *dev = master->dev;

	if (!master->iopf_enabled)
	return;

	iommu_unregister_device_fault_handler(dev);
	iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
	}

	int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
	{
	int ret;

	mutex_lock(&sva_lock);
	ret = arm_smmu_master_sva_enable_iopf(master);
	if (!ret)
	master->sva_enabled = true;
	mutex_unlock(&sva_lock);

	return ret;
	}

	int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
	{
	mutex_lock(&sva_lock);
	if (!list_empty(&master->bonds)) {
	dev_err(master->dev, "cannot disable SVA, device is bound\n");
	mutex_unlock(&sva_lock);
	return -EBUSY;
	}
	arm_smmu_master_sva_disable_iopf(master);
	master->sva_enabled = false;
	mutex_unlock(&sva_lock);

	return 0;
	}

	void arm_smmu_sva_notifier_synchronize(void)
	{
	/*
	* Some MMU notifiers may still be waiting to be freed, using
	* arm_smmu_mmu_notifier_free(). Wait for them.
	*/
	mmu_notifier_synchronize();
	}