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 | 248 |
1 files changed, 248 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 000000000000..9255c9600fb8 --- /dev/null +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c @@ -0,0 +1,248 @@ +// 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/slab.h> + +#include "arm-smmu-v3.h" +#include "../../io-pgtable-arm.h" + +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; +} + +__maybe_unused +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; +} + +__maybe_unused +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); + } +} + +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_BTM | 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; +} + +static bool arm_smmu_iopf_supported(struct arm_smmu_master *master) +{ + return false; +} + +bool arm_smmu_master_sva_supported(struct arm_smmu_master *master) +{ + if (!(master->smmu->features & ARM_SMMU_FEAT_SVA)) + return false; + + /* SSID and IOPF support are mandatory for the moment */ + return master->ssid_bits && arm_smmu_iopf_supported(master); +} + +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; +} + +int arm_smmu_master_enable_sva(struct arm_smmu_master *master) +{ + mutex_lock(&sva_lock); + master->sva_enabled = true; + mutex_unlock(&sva_lock); + + return 0; +} + +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; + } + master->sva_enabled = false; + mutex_unlock(&sva_lock); + + return 0; +} |