xtensa: support DMA buffers in high memory

[cris-mirror.git] / drivers / iommu / io-pgtable-arm.c

/*
 * CPU-agnostic ARM page table allocator.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright (C) 2014 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

#define pr_fmt(fmt)     "arm-lpae io-pgtable: " fmt

#include <linux/atomic.h>
#include <linux/iommu.h>
#include <linux/kernel.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/dma-mapping.h>

#include <asm/barrier.h>

#include "io-pgtable.h"

#define ARM_LPAE_MAX_ADDR_BITS          48
#define ARM_LPAE_S2_MAX_CONCAT_PAGES    16
#define ARM_LPAE_MAX_LEVELS             4

/* Struct accessors */
#define io_pgtable_to_data(x)                                           \
        container_of((x), struct arm_lpae_io_pgtable, iop)

#define io_pgtable_ops_to_data(x)                                       \
        io_pgtable_to_data(io_pgtable_ops_to_pgtable(x))

/*
 * For consistency with the architecture, we always consider
 * ARM_LPAE_MAX_LEVELS levels, with the walk starting at level n >=0
 */
#define ARM_LPAE_START_LVL(d)           (ARM_LPAE_MAX_LEVELS - (d)->levels)

/*
 * Calculate the right shift amount to get to the portion describing level l
 * in a virtual address mapped by the pagetable in d.
 */
#define ARM_LPAE_LVL_SHIFT(l,d)                                         \
        ((((d)->levels - ((l) - ARM_LPAE_START_LVL(d) + 1))             \
          * (d)->bits_per_level) + (d)->pg_shift)

#define ARM_LPAE_GRANULE(d)             (1UL << (d)->pg_shift)

#define ARM_LPAE_PAGES_PER_PGD(d)                                       \
        DIV_ROUND_UP((d)->pgd_size, ARM_LPAE_GRANULE(d))

/*
 * Calculate the index at level l used to map virtual address a using the
 * pagetable in d.
 */
#define ARM_LPAE_PGD_IDX(l,d)                                           \
        ((l) == ARM_LPAE_START_LVL(d) ? ilog2(ARM_LPAE_PAGES_PER_PGD(d)) : 0)

#define ARM_LPAE_LVL_IDX(a,l,d)                                         \
        (((u64)(a) >> ARM_LPAE_LVL_SHIFT(l,d)) &                        \
         ((1 << ((d)->bits_per_level + ARM_LPAE_PGD_IDX(l,d))) - 1))

/* Calculate the block/page mapping size at level l for pagetable in d. */
#define ARM_LPAE_BLOCK_SIZE(l,d)                                        \
        (1ULL << (ilog2(sizeof(arm_lpae_iopte)) +                       \
                ((ARM_LPAE_MAX_LEVELS - (l)) * (d)->bits_per_level)))

/* Page table bits */
#define ARM_LPAE_PTE_TYPE_SHIFT         0
#define ARM_LPAE_PTE_TYPE_MASK          0x3

#define ARM_LPAE_PTE_TYPE_BLOCK         1
#define ARM_LPAE_PTE_TYPE_TABLE         3
#define ARM_LPAE_PTE_TYPE_PAGE          3

#define ARM_LPAE_PTE_NSTABLE            (((arm_lpae_iopte)1) << 63)
#define ARM_LPAE_PTE_XN                 (((arm_lpae_iopte)3) << 53)
#define ARM_LPAE_PTE_AF                 (((arm_lpae_iopte)1) << 10)
#define ARM_LPAE_PTE_SH_NS              (((arm_lpae_iopte)0) << 8)
#define ARM_LPAE_PTE_SH_OS              (((arm_lpae_iopte)2) << 8)
#define ARM_LPAE_PTE_SH_IS              (((arm_lpae_iopte)3) << 8)
#define ARM_LPAE_PTE_NS                 (((arm_lpae_iopte)1) << 5)
#define ARM_LPAE_PTE_VALID              (((arm_lpae_iopte)1) << 0)

#define ARM_LPAE_PTE_ATTR_LO_MASK       (((arm_lpae_iopte)0x3ff) << 2)
/* Ignore the contiguous bit for block splitting */
#define ARM_LPAE_PTE_ATTR_HI_MASK       (((arm_lpae_iopte)6) << 52)
#define ARM_LPAE_PTE_ATTR_MASK          (ARM_LPAE_PTE_ATTR_LO_MASK |    \
                                         ARM_LPAE_PTE_ATTR_HI_MASK)
/* Software bit for solving coherency races */
#define ARM_LPAE_PTE_SW_SYNC            (((arm_lpae_iopte)1) << 55)

/* Stage-1 PTE */
#define ARM_LPAE_PTE_AP_UNPRIV          (((arm_lpae_iopte)1) << 6)
#define ARM_LPAE_PTE_AP_RDONLY          (((arm_lpae_iopte)2) << 6)
#define ARM_LPAE_PTE_ATTRINDX_SHIFT     2
#define ARM_LPAE_PTE_nG                 (((arm_lpae_iopte)1) << 11)

/* Stage-2 PTE */
#define ARM_LPAE_PTE_HAP_FAULT          (((arm_lpae_iopte)0) << 6)
#define ARM_LPAE_PTE_HAP_READ           (((arm_lpae_iopte)1) << 6)
#define ARM_LPAE_PTE_HAP_WRITE          (((arm_lpae_iopte)2) << 6)
#define ARM_LPAE_PTE_MEMATTR_OIWB       (((arm_lpae_iopte)0xf) << 2)
#define ARM_LPAE_PTE_MEMATTR_NC         (((arm_lpae_iopte)0x5) << 2)
#define ARM_LPAE_PTE_MEMATTR_DEV        (((arm_lpae_iopte)0x1) << 2)

/* Register bits */
#define ARM_32_LPAE_TCR_EAE             (1 << 31)
#define ARM_64_LPAE_S2_TCR_RES1         (1 << 31)

#define ARM_LPAE_TCR_EPD1               (1 << 23)

#define ARM_LPAE_TCR_TG0_4K             (0 << 14)
#define ARM_LPAE_TCR_TG0_64K            (1 << 14)
#define ARM_LPAE_TCR_TG0_16K            (2 << 14)

#define ARM_LPAE_TCR_SH0_SHIFT          12
#define ARM_LPAE_TCR_SH0_MASK           0x3
#define ARM_LPAE_TCR_SH_NS              0
#define ARM_LPAE_TCR_SH_OS              2
#define ARM_LPAE_TCR_SH_IS              3

#define ARM_LPAE_TCR_ORGN0_SHIFT        10
#define ARM_LPAE_TCR_IRGN0_SHIFT        8
#define ARM_LPAE_TCR_RGN_MASK           0x3
#define ARM_LPAE_TCR_RGN_NC             0
#define ARM_LPAE_TCR_RGN_WBWA           1
#define ARM_LPAE_TCR_RGN_WT             2
#define ARM_LPAE_TCR_RGN_WB             3

#define ARM_LPAE_TCR_SL0_SHIFT          6
#define ARM_LPAE_TCR_SL0_MASK           0x3

#define ARM_LPAE_TCR_T0SZ_SHIFT         0
#define ARM_LPAE_TCR_SZ_MASK            0xf

#define ARM_LPAE_TCR_PS_SHIFT           16
#define ARM_LPAE_TCR_PS_MASK            0x7

#define ARM_LPAE_TCR_IPS_SHIFT          32
#define ARM_LPAE_TCR_IPS_MASK           0x7

#define ARM_LPAE_TCR_PS_32_BIT          0x0ULL
#define ARM_LPAE_TCR_PS_36_BIT          0x1ULL
#define ARM_LPAE_TCR_PS_40_BIT          0x2ULL
#define ARM_LPAE_TCR_PS_42_BIT          0x3ULL
#define ARM_LPAE_TCR_PS_44_BIT          0x4ULL
#define ARM_LPAE_TCR_PS_48_BIT          0x5ULL

#define ARM_LPAE_MAIR_ATTR_SHIFT(n)     ((n) << 3)
#define ARM_LPAE_MAIR_ATTR_MASK         0xff
#define ARM_LPAE_MAIR_ATTR_DEVICE       0x04
#define ARM_LPAE_MAIR_ATTR_NC           0x44
#define ARM_LPAE_MAIR_ATTR_WBRWA        0xff
#define ARM_LPAE_MAIR_ATTR_IDX_NC       0
#define ARM_LPAE_MAIR_ATTR_IDX_CACHE    1
#define ARM_LPAE_MAIR_ATTR_IDX_DEV      2

/* IOPTE accessors */
#define iopte_deref(pte,d)                                      \
        (__va((pte) & ((1ULL << ARM_LPAE_MAX_ADDR_BITS) - 1)    \
        & ~(ARM_LPAE_GRANULE(d) - 1ULL)))

#define iopte_type(pte,l)                                       \
        (((pte) >> ARM_LPAE_PTE_TYPE_SHIFT) & ARM_LPAE_PTE_TYPE_MASK)

#define iopte_prot(pte) ((pte) & ARM_LPAE_PTE_ATTR_MASK)

#define iopte_leaf(pte,l)                                       \
        (l == (ARM_LPAE_MAX_LEVELS - 1) ?                       \
                (iopte_type(pte,l) == ARM_LPAE_PTE_TYPE_PAGE) : \
                (iopte_type(pte,l) == ARM_LPAE_PTE_TYPE_BLOCK))

#define iopte_to_pfn(pte,d)                                     \
        (((pte) & ((1ULL << ARM_LPAE_MAX_ADDR_BITS) - 1)) >> (d)->pg_shift)

#define pfn_to_iopte(pfn,d)                                     \
        (((pfn) << (d)->pg_shift) & ((1ULL << ARM_LPAE_MAX_ADDR_BITS) - 1))

struct arm_lpae_io_pgtable {
        struct io_pgtable       iop;

        int                     levels;
        size_t                  pgd_size;
        unsigned long           pg_shift;
        unsigned long           bits_per_level;

        void                    *pgd;
};

typedef u64 arm_lpae_iopte;

static bool selftest_running = false;

static dma_addr_t __arm_lpae_dma_addr(void *pages)
{
        return (dma_addr_t)virt_to_phys(pages);
}

static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
                                    struct io_pgtable_cfg *cfg)
{
        struct device *dev = cfg->iommu_dev;
        dma_addr_t dma;
        void *pages = alloc_pages_exact(size, gfp | __GFP_ZERO);

        if (!pages)
                return NULL;

        if (!(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA)) {
                dma = dma_map_single(dev, pages, size, DMA_TO_DEVICE);
                if (dma_mapping_error(dev, dma))
                        goto out_free;
                /*
                 * We depend on the IOMMU being able to work with any physical
                 * address directly, so if the DMA layer suggests otherwise by
                 * translating or truncating them, that bodes very badly...
                 */
                if (dma != virt_to_phys(pages))
                        goto out_unmap;
        }

        return pages;

out_unmap:
        dev_err(dev, "Cannot accommodate DMA translation for IOMMU page tables\n");
        dma_unmap_single(dev, dma, size, DMA_TO_DEVICE);
out_free:
        free_pages_exact(pages, size);
        return NULL;
}

static void __arm_lpae_free_pages(void *pages, size_t size,
                                  struct io_pgtable_cfg *cfg)
{
        if (!(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA))
                dma_unmap_single(cfg->iommu_dev, __arm_lpae_dma_addr(pages),
                                 size, DMA_TO_DEVICE);
        free_pages_exact(pages, size);
}

static void __arm_lpae_sync_pte(arm_lpae_iopte *ptep,
                                struct io_pgtable_cfg *cfg)
{
        dma_sync_single_for_device(cfg->iommu_dev, __arm_lpae_dma_addr(ptep),
                                   sizeof(*ptep), DMA_TO_DEVICE);
}

static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte,
                               struct io_pgtable_cfg *cfg)
{
        *ptep = pte;

        if (!(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA))
                __arm_lpae_sync_pte(ptep, cfg);
}

static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
                            unsigned long iova, size_t size, int lvl,
                            arm_lpae_iopte *ptep);

static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
                                phys_addr_t paddr, arm_lpae_iopte prot,
                                int lvl, arm_lpae_iopte *ptep)
{
        arm_lpae_iopte pte = prot;

        if (data->iop.cfg.quirks & IO_PGTABLE_QUIRK_ARM_NS)
                pte |= ARM_LPAE_PTE_NS;

        if (lvl == ARM_LPAE_MAX_LEVELS - 1)
                pte |= ARM_LPAE_PTE_TYPE_PAGE;
        else
                pte |= ARM_LPAE_PTE_TYPE_BLOCK;

        pte |= ARM_LPAE_PTE_AF | ARM_LPAE_PTE_SH_IS;
        pte |= pfn_to_iopte(paddr >> data->pg_shift, data);

        __arm_lpae_set_pte(ptep, pte, &data->iop.cfg);
}

static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
                             unsigned long iova, phys_addr_t paddr,
                             arm_lpae_iopte prot, int lvl,
                             arm_lpae_iopte *ptep)
{
        arm_lpae_iopte pte = *ptep;

        if (iopte_leaf(pte, lvl)) {
                /* We require an unmap first */
                WARN_ON(!selftest_running);
                return -EEXIST;
        } else if (iopte_type(pte, lvl) == ARM_LPAE_PTE_TYPE_TABLE) {
                /*
                 * We need to unmap and free the old table before
                 * overwriting it with a block entry.
                 */
                arm_lpae_iopte *tblp;
                size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);

                tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data);
                if (WARN_ON(__arm_lpae_unmap(data, iova, sz, lvl, tblp) != sz))
                        return -EINVAL;
        }

        __arm_lpae_init_pte(data, paddr, prot, lvl, ptep);
        return 0;
}

static arm_lpae_iopte arm_lpae_install_table(arm_lpae_iopte *table,
                                             arm_lpae_iopte *ptep,
                                             arm_lpae_iopte curr,
                                             struct io_pgtable_cfg *cfg)
{
        arm_lpae_iopte old, new;

        new = __pa(table) | ARM_LPAE_PTE_TYPE_TABLE;
        if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS)
                new |= ARM_LPAE_PTE_NSTABLE;

        /*
         * Ensure the table itself is visible before its PTE can be.
         * Whilst we could get away with cmpxchg64_release below, this
         * doesn't have any ordering semantics when !CONFIG_SMP.
         */
        dma_wmb();

        old = cmpxchg64_relaxed(ptep, curr, new);

        if ((cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA) ||
            (old & ARM_LPAE_PTE_SW_SYNC))
                return old;

        /* Even if it's not ours, there's no point waiting; just kick it */
        __arm_lpae_sync_pte(ptep, cfg);
        if (old == curr)
                WRITE_ONCE(*ptep, new | ARM_LPAE_PTE_SW_SYNC);

        return old;
}

static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
                          phys_addr_t paddr, size_t size, arm_lpae_iopte prot,
                          int lvl, arm_lpae_iopte *ptep)
{
        arm_lpae_iopte *cptep, pte;
        size_t block_size = ARM_LPAE_BLOCK_SIZE(lvl, data);
        size_t tblsz = ARM_LPAE_GRANULE(data);
        struct io_pgtable_cfg *cfg = &data->iop.cfg;

        /* Find our entry at the current level */
        ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);

        /* If we can install a leaf entry at this level, then do so */
        if (size == block_size && (size & cfg->pgsize_bitmap))
                return arm_lpae_init_pte(data, iova, paddr, prot, lvl, ptep);

        /* We can't allocate tables at the final level */
        if (WARN_ON(lvl >= ARM_LPAE_MAX_LEVELS - 1))
                return -EINVAL;

        /* Grab a pointer to the next level */
        pte = READ_ONCE(*ptep);
        if (!pte) {
                cptep = __arm_lpae_alloc_pages(tblsz, GFP_ATOMIC, cfg);
                if (!cptep)
                        return -ENOMEM;

                pte = arm_lpae_install_table(cptep, ptep, 0, cfg);
                if (pte)
                        __arm_lpae_free_pages(cptep, tblsz, cfg);
        } else if (!(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA) &&
                   !(pte & ARM_LPAE_PTE_SW_SYNC)) {
                __arm_lpae_sync_pte(ptep, cfg);
        }

        if (pte && !iopte_leaf(pte, lvl)) {
                cptep = iopte_deref(pte, data);
        } else if (pte) {
                /* We require an unmap first */
                WARN_ON(!selftest_running);
                return -EEXIST;
        }

        /* Rinse, repeat */
        return __arm_lpae_map(data, iova, paddr, size, prot, lvl + 1, cptep);
}

static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
                                           int prot)
{
        arm_lpae_iopte pte;

        if (data->iop.fmt == ARM_64_LPAE_S1 ||
            data->iop.fmt == ARM_32_LPAE_S1) {
                pte = ARM_LPAE_PTE_nG;

                if (!(prot & IOMMU_WRITE) && (prot & IOMMU_READ))
                        pte |= ARM_LPAE_PTE_AP_RDONLY;

                if (!(prot & IOMMU_PRIV))
                        pte |= ARM_LPAE_PTE_AP_UNPRIV;

                if (prot & IOMMU_MMIO)
                        pte |= (ARM_LPAE_MAIR_ATTR_IDX_DEV
                                << ARM_LPAE_PTE_ATTRINDX_SHIFT);
                else if (prot & IOMMU_CACHE)
                        pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE
                                << ARM_LPAE_PTE_ATTRINDX_SHIFT);
        } else {
                pte = ARM_LPAE_PTE_HAP_FAULT;
                if (prot & IOMMU_READ)
                        pte |= ARM_LPAE_PTE_HAP_READ;
                if (prot & IOMMU_WRITE)
                        pte |= ARM_LPAE_PTE_HAP_WRITE;
                if (prot & IOMMU_MMIO)
                        pte |= ARM_LPAE_PTE_MEMATTR_DEV;
                else if (prot & IOMMU_CACHE)
                        pte |= ARM_LPAE_PTE_MEMATTR_OIWB;
                else
                        pte |= ARM_LPAE_PTE_MEMATTR_NC;
        }

        if (prot & IOMMU_NOEXEC)
                pte |= ARM_LPAE_PTE_XN;

        return pte;
}

static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
                        phys_addr_t paddr, size_t size, int iommu_prot)
{
        struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
        arm_lpae_iopte *ptep = data->pgd;
        int ret, lvl = ARM_LPAE_START_LVL(data);
        arm_lpae_iopte prot;

        /* If no access, then nothing to do */
        if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
                return 0;

        if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) ||
                    paddr >= (1ULL << data->iop.cfg.oas)))
                return -ERANGE;

        prot = arm_lpae_prot_to_pte(data, iommu_prot);
        ret = __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep);
        /*
         * Synchronise all PTE updates for the new mapping before there's
         * a chance for anything to kick off a table walk for the new iova.
         */
        wmb();

        return ret;
}

static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
                                    arm_lpae_iopte *ptep)
{
        arm_lpae_iopte *start, *end;
        unsigned long table_size;

        if (lvl == ARM_LPAE_START_LVL(data))
                table_size = data->pgd_size;
        else
                table_size = ARM_LPAE_GRANULE(data);

        start = ptep;

        /* Only leaf entries at the last level */
        if (lvl == ARM_LPAE_MAX_LEVELS - 1)
                end = ptep;
        else
                end = (void *)ptep + table_size;

        while (ptep != end) {
                arm_lpae_iopte pte = *ptep++;

                if (!pte || iopte_leaf(pte, lvl))
                        continue;

                __arm_lpae_free_pgtable(data, lvl + 1, iopte_deref(pte, data));
        }

        __arm_lpae_free_pages(start, table_size, &data->iop.cfg);
}

static void arm_lpae_free_pgtable(struct io_pgtable *iop)
{
        struct arm_lpae_io_pgtable *data = io_pgtable_to_data(iop);

        __arm_lpae_free_pgtable(data, ARM_LPAE_START_LVL(data), data->pgd);
        kfree(data);
}

static int arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
                                    unsigned long iova, size_t size,
                                    arm_lpae_iopte blk_pte, int lvl,
                                    arm_lpae_iopte *ptep)
{
        struct io_pgtable_cfg *cfg = &data->iop.cfg;
        arm_lpae_iopte pte, *tablep;
        phys_addr_t blk_paddr;
        size_t tablesz = ARM_LPAE_GRANULE(data);
        size_t split_sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
        int i, unmap_idx = -1;

        if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
                return 0;

        tablep = __arm_lpae_alloc_pages(tablesz, GFP_ATOMIC, cfg);
        if (!tablep)
                return 0; /* Bytes unmapped */

        if (size == split_sz)
                unmap_idx = ARM_LPAE_LVL_IDX(iova, lvl, data);

        blk_paddr = iopte_to_pfn(blk_pte, data) << data->pg_shift;
        pte = iopte_prot(blk_pte);

        for (i = 0; i < tablesz / sizeof(pte); i++, blk_paddr += split_sz) {
                /* Unmap! */
                if (i == unmap_idx)
                        continue;

                __arm_lpae_init_pte(data, blk_paddr, pte, lvl, &tablep[i]);
        }

        pte = arm_lpae_install_table(tablep, ptep, blk_pte, cfg);
        if (pte != blk_pte) {
                __arm_lpae_free_pages(tablep, tablesz, cfg);
                /*
                 * We may race against someone unmapping another part of this
                 * block, but anything else is invalid. We can't misinterpret
                 * a page entry here since we're never at the last level.
                 */
                if (iopte_type(pte, lvl - 1) != ARM_LPAE_PTE_TYPE_TABLE)
                        return 0;

                tablep = iopte_deref(pte, data);
        }

        if (unmap_idx < 0)
                return __arm_lpae_unmap(data, iova, size, lvl, tablep);

        io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true);
        return size;
}

static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
                            unsigned long iova, size_t size, int lvl,
                            arm_lpae_iopte *ptep)
{
        arm_lpae_iopte pte;
        struct io_pgtable *iop = &data->iop;

        /* Something went horribly wrong and we ran out of page table */
        if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
                return 0;

        ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
        pte = READ_ONCE(*ptep);
        if (WARN_ON(!pte))
                return 0;

        /* If the size matches this level, we're in the right place */
        if (size == ARM_LPAE_BLOCK_SIZE(lvl, data)) {
                __arm_lpae_set_pte(ptep, 0, &iop->cfg);

                if (!iopte_leaf(pte, lvl)) {
                        /* Also flush any partial walks */
                        io_pgtable_tlb_add_flush(iop, iova, size,
                                                ARM_LPAE_GRANULE(data), false);
                        io_pgtable_tlb_sync(iop);
                        ptep = iopte_deref(pte, data);
                        __arm_lpae_free_pgtable(data, lvl + 1, ptep);
                } else {
                        io_pgtable_tlb_add_flush(iop, iova, size, size, true);
                }

                return size;
        } else if (iopte_leaf(pte, lvl)) {
                /*
                 * Insert a table at the next level to map the old region,
                 * minus the part we want to unmap
                 */
                return arm_lpae_split_blk_unmap(data, iova, size, pte,
                                                lvl + 1, ptep);
        }

        /* Keep on walkin' */
        ptep = iopte_deref(pte, data);
        return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep);
}

static int arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
                          size_t size)
{
        struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
        arm_lpae_iopte *ptep = data->pgd;
        int lvl = ARM_LPAE_START_LVL(data);

        if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
                return 0;

        return __arm_lpae_unmap(data, iova, size, lvl, ptep);
}

static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
                                         unsigned long iova)
{
        struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
        arm_lpae_iopte pte, *ptep = data->pgd;
        int lvl = ARM_LPAE_START_LVL(data);

        do {
                /* Valid IOPTE pointer? */
                if (!ptep)
                        return 0;

                /* Grab the IOPTE we're interested in */
                ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
                pte = READ_ONCE(*ptep);

                /* Valid entry? */
                if (!pte)
                        return 0;

                /* Leaf entry? */
                if (iopte_leaf(pte,lvl))
                        goto found_translation;

                /* Take it to the next level */
                ptep = iopte_deref(pte, data);
        } while (++lvl < ARM_LPAE_MAX_LEVELS);

        /* Ran out of page tables to walk */
        return 0;

found_translation:
        iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
        return ((phys_addr_t)iopte_to_pfn(pte,data) << data->pg_shift) | iova;
}

static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
{
        unsigned long granule;

        /*
         * We need to restrict the supported page sizes to match the
         * translation regime for a particular granule. Aim to match
         * the CPU page size if possible, otherwise prefer smaller sizes.
         * While we're at it, restrict the block sizes to match the
         * chosen granule.
         */
        if (cfg->pgsize_bitmap & PAGE_SIZE)
                granule = PAGE_SIZE;
        else if (cfg->pgsize_bitmap & ~PAGE_MASK)
                granule = 1UL << __fls(cfg->pgsize_bitmap & ~PAGE_MASK);
        else if (cfg->pgsize_bitmap & PAGE_MASK)
                granule = 1UL << __ffs(cfg->pgsize_bitmap & PAGE_MASK);
        else
                granule = 0;

        switch (granule) {
        case SZ_4K:
                cfg->pgsize_bitmap &= (SZ_4K | SZ_2M | SZ_1G);
                break;
        case SZ_16K:
                cfg->pgsize_bitmap &= (SZ_16K | SZ_32M);
                break;
        case SZ_64K:
                cfg->pgsize_bitmap &= (SZ_64K | SZ_512M);
                break;
        default:
                cfg->pgsize_bitmap = 0;
        }
}

static struct arm_lpae_io_pgtable *
arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
{
        unsigned long va_bits, pgd_bits;
        struct arm_lpae_io_pgtable *data;

        arm_lpae_restrict_pgsizes(cfg);

        if (!(cfg->pgsize_bitmap & (SZ_4K | SZ_16K | SZ_64K)))
                return NULL;

        if (cfg->ias > ARM_LPAE_MAX_ADDR_BITS)
                return NULL;

        if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
                return NULL;

        if (!selftest_running && cfg->iommu_dev->dma_pfn_offset) {
                dev_err(cfg->iommu_dev, "Cannot accommodate DMA offset for IOMMU page tables\n");
                return NULL;
        }

        data = kmalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return NULL;

        data->pg_shift = __ffs(cfg->pgsize_bitmap);
        data->bits_per_level = data->pg_shift - ilog2(sizeof(arm_lpae_iopte));

        va_bits = cfg->ias - data->pg_shift;
        data->levels = DIV_ROUND_UP(va_bits, data->bits_per_level);

        /* Calculate the actual size of our pgd (without concatenation) */
        pgd_bits = va_bits - (data->bits_per_level * (data->levels - 1));
        data->pgd_size = 1UL << (pgd_bits + ilog2(sizeof(arm_lpae_iopte)));

        data->iop.ops = (struct io_pgtable_ops) {
                .map            = arm_lpae_map,
                .unmap          = arm_lpae_unmap,
                .iova_to_phys   = arm_lpae_iova_to_phys,
        };

        return data;
}

static struct io_pgtable *
arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
{
        u64 reg;
        struct arm_lpae_io_pgtable *data;

        if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA))
                return NULL;

        data = arm_lpae_alloc_pgtable(cfg);
        if (!data)
                return NULL;

        /* TCR */
        reg = (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT) |
              (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN0_SHIFT) |
              (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN0_SHIFT);

        switch (ARM_LPAE_GRANULE(data)) {
        case SZ_4K:
                reg |= ARM_LPAE_TCR_TG0_4K;
                break;
        case SZ_16K:
                reg |= ARM_LPAE_TCR_TG0_16K;
                break;
        case SZ_64K:
                reg |= ARM_LPAE_TCR_TG0_64K;
                break;
        }

        switch (cfg->oas) {
        case 32:
                reg |= (ARM_LPAE_TCR_PS_32_BIT << ARM_LPAE_TCR_IPS_SHIFT);
                break;
        case 36:
                reg |= (ARM_LPAE_TCR_PS_36_BIT << ARM_LPAE_TCR_IPS_SHIFT);
                break;
        case 40:
                reg |= (ARM_LPAE_TCR_PS_40_BIT << ARM_LPAE_TCR_IPS_SHIFT);
                break;
        case 42:
                reg |= (ARM_LPAE_TCR_PS_42_BIT << ARM_LPAE_TCR_IPS_SHIFT);
                break;
        case 44:
                reg |= (ARM_LPAE_TCR_PS_44_BIT << ARM_LPAE_TCR_IPS_SHIFT);
                break;
        case 48:
                reg |= (ARM_LPAE_TCR_PS_48_BIT << ARM_LPAE_TCR_IPS_SHIFT);
                break;
        default:
                goto out_free_data;
        }

        reg |= (64ULL - cfg->ias) << ARM_LPAE_TCR_T0SZ_SHIFT;

        /* Disable speculative walks through TTBR1 */
        reg |= ARM_LPAE_TCR_EPD1;
        cfg->arm_lpae_s1_cfg.tcr = reg;

        /* MAIRs */
        reg = (ARM_LPAE_MAIR_ATTR_NC
               << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_NC)) |
              (ARM_LPAE_MAIR_ATTR_WBRWA
               << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_CACHE)) |
              (ARM_LPAE_MAIR_ATTR_DEVICE
               << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_DEV));

        cfg->arm_lpae_s1_cfg.mair[0] = reg;
        cfg->arm_lpae_s1_cfg.mair[1] = 0;

        /* Looking good; allocate a pgd */
        data->pgd = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
        if (!data->pgd)
                goto out_free_data;

        /* Ensure the empty pgd is visible before any actual TTBR write */
        wmb();

        /* TTBRs */
        cfg->arm_lpae_s1_cfg.ttbr[0] = virt_to_phys(data->pgd);
        cfg->arm_lpae_s1_cfg.ttbr[1] = 0;
        return &data->iop;

out_free_data:
        kfree(data);
        return NULL;
}

static struct io_pgtable *
arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
{
        u64 reg, sl;
        struct arm_lpae_io_pgtable *data;

        /* The NS quirk doesn't apply at stage 2 */
        if (cfg->quirks & ~IO_PGTABLE_QUIRK_NO_DMA)
                return NULL;

        data = arm_lpae_alloc_pgtable(cfg);
        if (!data)
                return NULL;

        /*
         * Concatenate PGDs at level 1 if possible in order to reduce
         * the depth of the stage-2 walk.
         */
        if (data->levels == ARM_LPAE_MAX_LEVELS) {
                unsigned long pgd_pages;

                pgd_pages = data->pgd_size >> ilog2(sizeof(arm_lpae_iopte));
                if (pgd_pages <= ARM_LPAE_S2_MAX_CONCAT_PAGES) {
                        data->pgd_size = pgd_pages << data->pg_shift;
                        data->levels--;
                }
        }

        /* VTCR */
        reg = ARM_64_LPAE_S2_TCR_RES1 |
             (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT) |
             (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN0_SHIFT) |
             (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN0_SHIFT);

        sl = ARM_LPAE_START_LVL(data);

        switch (ARM_LPAE_GRANULE(data)) {
        case SZ_4K:
                reg |= ARM_LPAE_TCR_TG0_4K;
                sl++; /* SL0 format is different for 4K granule size */
                break;
        case SZ_16K:
                reg |= ARM_LPAE_TCR_TG0_16K;
                break;
        case SZ_64K:
                reg |= ARM_LPAE_TCR_TG0_64K;
                break;
        }

        switch (cfg->oas) {
        case 32:
                reg |= (ARM_LPAE_TCR_PS_32_BIT << ARM_LPAE_TCR_PS_SHIFT);
                break;
        case 36:
                reg |= (ARM_LPAE_TCR_PS_36_BIT << ARM_LPAE_TCR_PS_SHIFT);
                break;
        case 40:
                reg |= (ARM_LPAE_TCR_PS_40_BIT << ARM_LPAE_TCR_PS_SHIFT);
                break;
        case 42:
                reg |= (ARM_LPAE_TCR_PS_42_BIT << ARM_LPAE_TCR_PS_SHIFT);
                break;
        case 44:
                reg |= (ARM_LPAE_TCR_PS_44_BIT << ARM_LPAE_TCR_PS_SHIFT);
                break;
        case 48:
                reg |= (ARM_LPAE_TCR_PS_48_BIT << ARM_LPAE_TCR_PS_SHIFT);
                break;
        default:
                goto out_free_data;
        }

        reg |= (64ULL - cfg->ias) << ARM_LPAE_TCR_T0SZ_SHIFT;
        reg |= (~sl & ARM_LPAE_TCR_SL0_MASK) << ARM_LPAE_TCR_SL0_SHIFT;
        cfg->arm_lpae_s2_cfg.vtcr = reg;

        /* Allocate pgd pages */
        data->pgd = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
        if (!data->pgd)
                goto out_free_data;

        /* Ensure the empty pgd is visible before any actual TTBR write */
        wmb();

        /* VTTBR */
        cfg->arm_lpae_s2_cfg.vttbr = virt_to_phys(data->pgd);
        return &data->iop;

out_free_data:
        kfree(data);
        return NULL;
}

static struct io_pgtable *
arm_32_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
{
        struct io_pgtable *iop;

        if (cfg->ias > 32 || cfg->oas > 40)
                return NULL;

        cfg->pgsize_bitmap &= (SZ_4K | SZ_2M | SZ_1G);
        iop = arm_64_lpae_alloc_pgtable_s1(cfg, cookie);
        if (iop) {
                cfg->arm_lpae_s1_cfg.tcr |= ARM_32_LPAE_TCR_EAE;
                cfg->arm_lpae_s1_cfg.tcr &= 0xffffffff;
        }

        return iop;
}

static struct io_pgtable *
arm_32_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
{
        struct io_pgtable *iop;

        if (cfg->ias > 40 || cfg->oas > 40)
                return NULL;

        cfg->pgsize_bitmap &= (SZ_4K | SZ_2M | SZ_1G);
        iop = arm_64_lpae_alloc_pgtable_s2(cfg, cookie);
        if (iop)
                cfg->arm_lpae_s2_cfg.vtcr &= 0xffffffff;

        return iop;
}

struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns = {
        .alloc  = arm_64_lpae_alloc_pgtable_s1,
        .free   = arm_lpae_free_pgtable,
};

struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s2_init_fns = {
        .alloc  = arm_64_lpae_alloc_pgtable_s2,
        .free   = arm_lpae_free_pgtable,
};

struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s1_init_fns = {
        .alloc  = arm_32_lpae_alloc_pgtable_s1,
        .free   = arm_lpae_free_pgtable,
};

struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s2_init_fns = {
        .alloc  = arm_32_lpae_alloc_pgtable_s2,
        .free   = arm_lpae_free_pgtable,
};

#ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST

static struct io_pgtable_cfg *cfg_cookie;

static void dummy_tlb_flush_all(void *cookie)
{
        WARN_ON(cookie != cfg_cookie);
}

static void dummy_tlb_add_flush(unsigned long iova, size_t size,
                                size_t granule, bool leaf, void *cookie)
{
        WARN_ON(cookie != cfg_cookie);
        WARN_ON(!(size & cfg_cookie->pgsize_bitmap));
}

static void dummy_tlb_sync(void *cookie)
{
        WARN_ON(cookie != cfg_cookie);
}

static const struct iommu_gather_ops dummy_tlb_ops __initconst = {
        .tlb_flush_all  = dummy_tlb_flush_all,
        .tlb_add_flush  = dummy_tlb_add_flush,
        .tlb_sync       = dummy_tlb_sync,
};

static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)
{
        struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
        struct io_pgtable_cfg *cfg = &data->iop.cfg;

        pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit\n",
                cfg->pgsize_bitmap, cfg->ias);
        pr_err("data: %d levels, 0x%zx pgd_size, %lu pg_shift, %lu bits_per_level, pgd @ %p\n",
                data->levels, data->pgd_size, data->pg_shift,
                data->bits_per_level, data->pgd);
}

#define __FAIL(ops, i)  ({                                              \
                WARN(1, "selftest: test failed for fmt idx %d\n", (i)); \
                arm_lpae_dump_ops(ops);                                 \
                selftest_running = false;                               \
                -EFAULT;                                                \
})

static int __init arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
{
        static const enum io_pgtable_fmt fmts[] = {
                ARM_64_LPAE_S1,
                ARM_64_LPAE_S2,
        };

        int i, j;
        unsigned long iova;
        size_t size;
        struct io_pgtable_ops *ops;

        selftest_running = true;

        for (i = 0; i < ARRAY_SIZE(fmts); ++i) {
                cfg_cookie = cfg;
                ops = alloc_io_pgtable_ops(fmts[i], cfg, cfg);
                if (!ops) {
                        pr_err("selftest: failed to allocate io pgtable ops\n");
                        return -ENOMEM;
                }

                /*
                 * Initial sanity checks.
                 * Empty page tables shouldn't provide any translations.
                 */
                if (ops->iova_to_phys(ops, 42))
                        return __FAIL(ops, i);

                if (ops->iova_to_phys(ops, SZ_1G + 42))
                        return __FAIL(ops, i);

                if (ops->iova_to_phys(ops, SZ_2G + 42))
                        return __FAIL(ops, i);

                /*
                 * Distinct mappings of different granule sizes.
                 */
                iova = 0;
                for_each_set_bit(j, &cfg->pgsize_bitmap, BITS_PER_LONG) {
                        size = 1UL << j;

                        if (ops->map(ops, iova, iova, size, IOMMU_READ |
                                                            IOMMU_WRITE |
                                                            IOMMU_NOEXEC |
                                                            IOMMU_CACHE))
                                return __FAIL(ops, i);

                        /* Overlapping mappings */
                        if (!ops->map(ops, iova, iova + size, size,
                                      IOMMU_READ | IOMMU_NOEXEC))
                                return __FAIL(ops, i);

                        if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
                                return __FAIL(ops, i);

                        iova += SZ_1G;
                }

                /* Partial unmap */
                size = 1UL << __ffs(cfg->pgsize_bitmap);
                if (ops->unmap(ops, SZ_1G + size, size) != size)
                        return __FAIL(ops, i);

                /* Remap of partial unmap */
                if (ops->map(ops, SZ_1G + size, size, size, IOMMU_READ))
                        return __FAIL(ops, i);

                if (ops->iova_to_phys(ops, SZ_1G + size + 42) != (size + 42))
                        return __FAIL(ops, i);

                /* Full unmap */
                iova = 0;
                j = find_first_bit(&cfg->pgsize_bitmap, BITS_PER_LONG);
                while (j != BITS_PER_LONG) {
                        size = 1UL << j;

                        if (ops->unmap(ops, iova, size) != size)
                                return __FAIL(ops, i);

                        if (ops->iova_to_phys(ops, iova + 42))
                                return __FAIL(ops, i);

                        /* Remap full block */
                        if (ops->map(ops, iova, iova, size, IOMMU_WRITE))
                                return __FAIL(ops, i);

                        if (ops->iova_to_phys(ops, iova + 42) != (iova + 42))
                                return __FAIL(ops, i);

                        iova += SZ_1G;
                        j++;
                        j = find_next_bit(&cfg->pgsize_bitmap, BITS_PER_LONG, j);
                }

                free_io_pgtable_ops(ops);
        }

        selftest_running = false;
        return 0;
}

static int __init arm_lpae_do_selftests(void)
{
        static const unsigned long pgsize[] = {
                SZ_4K | SZ_2M | SZ_1G,
                SZ_16K | SZ_32M,
                SZ_64K | SZ_512M,
        };

        static const unsigned int ias[] = {
                32, 36, 40, 42, 44, 48,
        };

        int i, j, pass = 0, fail = 0;
        struct io_pgtable_cfg cfg = {
                .tlb = &dummy_tlb_ops,
                .oas = 48,
                .quirks = IO_PGTABLE_QUIRK_NO_DMA,
        };

        for (i = 0; i < ARRAY_SIZE(pgsize); ++i) {
                for (j = 0; j < ARRAY_SIZE(ias); ++j) {
                        cfg.pgsize_bitmap = pgsize[i];
                        cfg.ias = ias[j];
                        pr_info("selftest: pgsize_bitmap 0x%08lx, IAS %u\n",
                                pgsize[i], ias[j]);
                        if (arm_lpae_run_tests(&cfg))
                                fail++;
                        else
                                pass++;
                }
        }

        pr_info("selftest: completed with %d PASS %d FAIL\n", pass, fail);
        return fail ? -EFAULT : 0;
}
subsys_initcall(arm_lpae_do_selftests);
#endif