diff options
Diffstat (limited to 'drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c')
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 573 |
1 files changed, 573 insertions, 0 deletions
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c new file mode 100644 index 000000000..ffba8ce93 --- /dev/null +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c @@ -0,0 +1,573 @@ +// 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/sched/mm.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; + + /* Don't free the mm until we release the ASID */ + mmgrab(mm); + + asid = arm64_mm_context_get(mm); + if (!asid) { + err = -ESRCH; + goto out_drop_mm; + } + + 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_EL1_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); +out_drop_mm: + mmdrop(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); + mmdrop(cd->mm); + kfree(cd); + } +} + +/* + * Cloned from the MAX_TLBI_OPS in arch/arm64/include/asm/tlbflush.h, this + * is used as a threshold to replace per-page TLBI commands to issue in the + * command queue with an address-space TLBI command, when SMMU w/o a range + * invalidation feature handles too many per-page TLBI commands, which will + * otherwise result in a soft lockup. + */ +#define CMDQ_MAX_TLBI_OPS (1 << (PAGE_SHIFT - 3)) + +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; + + /* + * The mm_types defines vm_end as the first byte after the end address, + * different from IOMMU subsystem using the last address of an address + * range. So do a simple translation here by calculating size correctly. + */ + size = end - start; + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_RANGE_INV)) { + if (size >= CMDQ_MAX_TLBI_OPS * PAGE_SIZE) + size = 0; + } + + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM)) { + if (!size) + arm_smmu_tlb_inv_asid(smmu_domain->smmu, + smmu_mn->cd->asid); + else + 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_bond; + } + + list_add(&bond->list, &master->bonds); + return &bond->sva; + +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); + 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_EL1_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_EL1_ASIDBITS_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(); +} |