table_walker.hh

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#ifndef __ARCH_ARM_TABLE_WALKER_HH__
#define __ARCH_ARM_TABLE_WALKER_HH__
 
#include <list>
 
#include "arch/arm/faults.hh"
#include "arch/arm/mmu.hh"
#include "arch/arm/regs/misc.hh"
#include "arch/arm/system.hh"
#include "arch/arm/tlb.hh"
#include "arch/arm/types.hh"
#include "arch/generic/mmu.hh"
#include "mem/packet_queue.hh"
#include "mem/qport.hh"
#include "mem/request.hh"
#include "sim/clocked_object.hh"
#include "sim/eventq.hh"
 
namespace gem5
{
 
struct ArmTableWalkerParams;
 
class ThreadContext;
 
namespace ArmISA {
class Translation;
class TLB;
 
class TableWalker : public ClockedObject
{
    using LookupLevel = enums::ArmLookupLevel;
 
  public:
    class WalkerState;
 
    class DescriptorBase
    {
      public:
        DescriptorBase() : lookupLevel(LookupLevel::L0) {}
        virtual ~DescriptorBase() = default;

        LookupLevel lookupLevel;
 
        virtual Addr pfn() const = 0;
        virtual DomainType domain() const = 0;
        virtual bool xn() const = 0;
        virtual uint8_t ap() const = 0;
        virtual bool global(WalkerState *currState) const = 0;
        virtual uint8_t offsetBits() const = 0;
        virtual bool secure(bool have_security, WalkerState *currState) const = 0;
        virtual std::string dbgHeader() const = 0;
        virtual uint8_t* getRawPtr() = 0;
        virtual uint64_t getRawData() const = 0;
        virtual uint8_t texcb() const
        {
            panic("texcb() not implemented for this class\n");
        }
        virtual bool shareable() const
        {
            panic("shareable() not implemented for this class\n");
        }
    };
 
    class L1Descriptor : public DescriptorBase
    {
      public:
        enum EntryType
        {
            Ignore,
            PageTable,
            Section,
            Reserved
        };

        uint32_t data;

        bool _dirty;

        L1Descriptor() : data(0), _dirty(false)
        {
            lookupLevel = LookupLevel::L1;
        }
        virtual ~L1Descriptor() = default;
 
        uint8_t*
        getRawPtr() override
        {
            return reinterpret_cast<uint8_t*>(&data);
        }
 
        uint64_t
        getRawData() const override
        {
            return (data);
        }
 
        std::string
        dbgHeader() const override
        {
            return "Inserting Section Descriptor into TLB\n";
        }
 
        uint8_t
        offsetBits() const override
        {
            return 20;
        }
 
        EntryType
        type() const
        {
            return (EntryType)(data & 0x3);
        }

        bool
        supersection() const
        {
            return bits(data, 18);
        }

        Addr
        paddr() const
        {
            if (supersection())
                panic("Super sections not implemented\n");
            return mbits(data, 31, 20);
        }

        Addr
        paddr(Addr va) const
        {
            if (supersection())
                panic("Super sections not implemented\n");
            return mbits(data, 31, 20) | mbits(va, 19, 0);
        }

        Addr
        pfn() const override
        {
            if (supersection())
                panic("Super sections not implemented\n");
            return bits(data, 31, 20);
        }

        bool
        global(WalkerState *currState) const override
        {
            return !bits(data, 17);
        }

        bool
        xn() const override
        {
            return bits(data, 4);
        }

        uint8_t
        ap() const override
        {
            return (bits(data, 15) << 2) | bits(data, 11, 10);
        }

        DomainType
        domain() const override
        {
            return static_cast<DomainType>(bits(data, 8, 5));
        }

        Addr
        l2Addr() const
        {
            return mbits(data, 31, 10);
        }

        uint8_t
        texcb() const override
        {
            return bits(data, 2) | bits(data, 3) << 1 | bits(data, 14, 12) << 2;
        }

        bool
        shareable() const override
        {
            return bits(data, 16);
        }

        void
        setAp0()
        {
            data |= 1 << 10;
            _dirty = true;
        }

        bool
        dirty() const
        {
            return _dirty;
        }

        bool
        secure(bool have_security, WalkerState *currState) const override
        {
            if (have_security && currState->secureLookup) {
                if (type() == PageTable)
                    return !bits(data, 3);
                else
                    return !bits(data, 19);
            }
            return false;
        }
    };

    class L2Descriptor : public DescriptorBase
    {
      public:
        uint32_t     data;
        L1Descriptor *l1Parent;

        bool _dirty;

        L2Descriptor() : data(0), l1Parent(nullptr), _dirty(false)
        {
            lookupLevel = LookupLevel::L2;
        }
 
        L2Descriptor(L1Descriptor &parent) : data(0), l1Parent(&parent),
                                             _dirty(false)
        {
            lookupLevel = LookupLevel::L2;
        }
 
        virtual ~L2Descriptor() = default;
 
        uint8_t*
        getRawPtr() override
        {
            return reinterpret_cast<uint8_t*>(&data);
        }
 
        uint64_t
        getRawData() const override
        {
            return (data);
        }
 
        std::string
        dbgHeader() const override
        {
            return "Inserting L2 Descriptor into TLB\n";
        }
 
        DomainType
        domain() const override
        {
            return l1Parent->domain();
        }
 
        bool
        secure(bool have_security, WalkerState *currState) const override
        {
            return l1Parent->secure(have_security, currState);
        }
 
        uint8_t
        offsetBits() const override
        {
            return large() ? 16 : 12;
        }

        bool
        invalid() const
        {
            return bits(data, 1, 0) == 0;
        }

        bool
        large() const
        {
            return bits(data, 1) == 0;
        }

        bool
        xn() const override
        {
            return large() ? bits(data, 15) : bits(data, 0);
        }

        bool
        global(WalkerState *currState) const override
        {
            return !bits(data, 11);
        }

        uint8_t
        ap() const override
        {
           return bits(data, 5, 4) | (bits(data, 9) << 2);
        }

        uint8_t
        texcb() const override
        {
            return large() ?
                (bits(data, 2) | (bits(data, 3) << 1) | (bits(data, 14, 12) << 2)) :
                (bits(data, 2) | (bits(data, 3) << 1) | (bits(data, 8, 6) << 2));
        }

        Addr
        pfn() const override
        {
            return large() ? bits(data, 31, 16) : bits(data, 31, 12);
        }

        Addr
        paddr(Addr va) const
        {
            if (large())
                return mbits(data, 31, 16) | mbits(va, 15, 0);
            else
                return mbits(data, 31, 12) | mbits(va, 11, 0);
        }

        bool
        shareable() const override
        {
            return bits(data, 10);
        }

        void
        setAp0()
        {
            data |= 1 << 4;
            _dirty = true;
        }

        bool
        dirty() const
        {
            return _dirty;
        }
 
    };

    class LongDescriptor : public DescriptorBase
    {
      public:
        enum EntryType
        {
            Invalid,
            Table,
            Block,
            Page
        };
 
        LongDescriptor()
          : data(0), _dirty(false), aarch64(false), grainSize(Grain4KB),
            physAddrRange(0), isStage2(false)
        {}

        uint64_t data;

        bool _dirty;

        bool aarch64;

        GrainSize grainSize;
 
        uint8_t physAddrRange;
 
        bool isStage2;
 
        uint8_t*
        getRawPtr() override
        {
            return reinterpret_cast<uint8_t*>(&data);
        }
 
        uint64_t
        getRawData() const override
        {
            return (data);
        }
 
        std::string
        dbgHeader() const override
        {
            switch (type()) {
              case LongDescriptor::Page:
                assert(lookupLevel == LookupLevel::L3);
                return "Inserting Page descriptor into TLB\n";
              case LongDescriptor::Block:
                assert(lookupLevel < LookupLevel::L3);
                return "Inserting Block descriptor into TLB\n";
              case LongDescriptor::Table:
                return "Inserting Table descriptor into TLB\n";
              default:
                panic("Trying to insert and invalid descriptor\n");
            }
        }

        bool
        secure(bool have_security, WalkerState *currState) const override
        {
            if (type() == Block || type() == Page) {
                if (isStage2) {
                    return have_security && currState->secureLookup &&
                        !currState->vtcr.nsa;
                } else {
                    return have_security &&
                        (currState->secureLookup && !bits(data, 5));
                }
            } else {
                return have_security && currState->secureLookup;
            }
        }

        EntryType
        type() const
        {
            switch (bits(data, 1, 0)) {
              case 0x1:
                // In AArch64 blocks are not allowed at L0 for the
                // 4 KiB granule and at L1 for 16/64 KiB granules
                switch (grainSize) {
                  case Grain4KB:
                    if (lookupLevel == LookupLevel::L0 ||
                        lookupLevel == LookupLevel::L3)
                        return Invalid;
                    else
                        return Block;
 
                  case Grain16KB:
                    if (lookupLevel == LookupLevel::L2)
                        return Block;
                    else
                        return Invalid;
 
                  case Grain64KB:
                    // With Armv8.2-LPA (52bit PA) L1 Block descriptors
                    // are allowed for 64KiB granule
                    if ((lookupLevel == LookupLevel::L1 && physAddrRange == 52) ||
                        lookupLevel == LookupLevel::L2)
                        return Block;
                    else
                        return Invalid;
 
                  default:
                    return Invalid;
                }
              case 0x3:
                return lookupLevel == LookupLevel::L3 ? Page : Table;
              default:
                return Invalid;
            }
        }

        uint8_t
        offsetBits() const override
        {
            if (type() == Block) {
                switch (grainSize) {
                    case Grain4KB:
                        return lookupLevel == LookupLevel::L1 ?
                            30 /* 1 GiB */ : 21 /* 2 MiB */;
                    case Grain16KB:
                        return 25  /* 32 MiB */;
                    case Grain64KB:
                        return lookupLevel == LookupLevel::L1 ?
                            42 /* 4 TiB */ : 29 /* 512 MiB */;
                    default:
                        panic("Invalid AArch64 VM granule size\n");
                }
            } else if (type() == Page) {
                switch (grainSize) {
                    case Grain4KB:
                    case Grain16KB:
                    case Grain64KB:
                        return grainSize; /* enum -> uint okay */
                    default:
                        panic("Invalid AArch64 VM granule size\n");
                }
            } else if (type() == Table) {
                const auto* ptops = getPageTableOps(grainSize);
                return ptops->walkBits(lookupLevel);
            }
            panic("AArch64 page table entry must be block or page\n");
        }

        Addr
        pfn() const override
        {
            return paddr() >> offsetBits();
        }

        Addr
        paddr() const
        {
            Addr addr = 0;
            if (aarch64) {
                addr = mbits(data, 47, offsetBits());
                if (physAddrRange == 52 && grainSize == Grain64KB) {
                    addr |= bits(data, 15, 12) << 48;
                }
            } else {
                addr = mbits(data, 39, offsetBits());
            }
            return addr;
        }

        Addr
        nextTableAddr() const
        {
            assert(type() == Table);
            Addr table_address = 0;
            if (aarch64) {
                table_address = mbits(data, 47, grainSize);
                // Using 52bit if Armv8.2-LPA is implemented
                if (physAddrRange == 52 && grainSize == Grain64KB)
                    table_address |= bits(data, 15, 12) << 48;
            } else {
                table_address = mbits(data, 39, 12);
            }
 
            return table_address;
        }

        Addr
        nextDescAddr(Addr va) const
        {
            assert(type() == Table);
            Addr pa = 0;
            if (aarch64) {
                int stride = grainSize - 3;
                int va_lo = stride * (3 - (lookupLevel + 1)) + grainSize;
                int va_hi = va_lo + stride - 1;
                pa = nextTableAddr() | (bits(va, va_hi, va_lo) << 3);
            } else {
                if (lookupLevel == LookupLevel::L1)
                    pa = nextTableAddr() | (bits(va, 29, 21) << 3);
                else  // lookupLevel == L2
                    pa = nextTableAddr() | (bits(va, 20, 12) << 3);
            }
            return pa;
        }

        bool
        xn() const override
        {
            assert(type() == Block || type() == Page);
            return bits(data, 54);
        }

        bool
        pxn() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 53);
        }

        bool
        contiguousHint() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 52);
        }

        bool
        global(WalkerState *currState) const override
        {
            assert(currState && (type() == Block || type() == Page));
            const bool secure_state = currState->ss == SecurityState::Secure;
            if (!currState->aarch64 && secure_state &&
                !currState->secureLookup) {
                return false;  // ARM ARM issue C B3.6.3
            } else if (currState->aarch64) {
                if (!MMU::hasUnprivRegime(currState->regime)) {
                    // By default translations are treated as global
                    // in AArch64 for regimes without an unpriviledged
                    // component
                    return true;
                } else if (secure_state && !currState->secureLookup) {
                    return false;
                }
            }
            return !bits(data, 11);
        }

        bool
        fnxs() const
        {
            assert((type() == Block || type() == Page));
            return bits(data, 11);
        }

        bool
        af() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 10);
        }

        uint8_t
        sh() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 9, 8);
        }

        uint8_t
        ap() const override
        {
            assert(type() == Block || type() == Page);
            // Long descriptors only support the AP[2:1] scheme
            return bits(data, 7, 6);
        }

        uint8_t
        piindex() const
        {
            assert(type() == Block || type() == Page);
            return (bits(data, 54) << 3) +
                (bits(data, 53) << 2) +
                (bits(data, 51) << 1) +
                bits(data, 6);
        }

        bool
        rw() const
        {
            assert(type() == Block || type() == Page);
            return !bits(data, 7);
        }

        bool
        user() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 6);
        }

        static uint8_t
        ap(bool rw, bool user)
        {
            return ((!rw) << 2) | (user << 1);
        }
 
        DomainType
        domain() const override
        {
            // Long-desc. format only supports Client domain
            return DomainType::Client;
        }

        uint8_t
        attrIndx() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 4, 2);
        }

        uint8_t
        memAttr() const
        {
            assert(type() == Block || type() == Page);
            return bits(data, 5, 2);
        }

        void
        setAf()
        {
            data |= 1 << 10;
            _dirty = true;
        }

        bool
        dirty() const
        {
            return _dirty;
        }

        bool
        secureTable() const
        {
            assert(type() == Table);
            return !bits(data, 63);
        }

        uint8_t
        apTable() const
        {
            assert(type() == Table);
            return bits(data, 62, 61);
        }

        uint8_t
        rwTable() const
        {
            assert(type() == Table);
            return !bits(data, 62);
        }

        uint8_t
        userTable() const
        {
            assert(type() == Table);
            return !bits(data, 61);
        }

        bool
        xnTable() const
        {
            assert(type() == Table);
            return bits(data, 60);
        }

        bool
        pxnTable() const
        {
            assert(type() == Table);
            return bits(data, 59);
        }
    };
 
    class WalkerState
    {
      public:
        ThreadContext *tc;

        bool aarch64;

        ExceptionLevel el;

        TranslationRegime regime;

        int physAddrRange;

        RequestPtr req;

        TlbEntry walkEntry;

        uint16_t asid;
        vmid_t vmid;

        BaseMMU::Translation *transState;

        Fault fault;

        Addr vaddr;

        Addr vaddr_tainted;

        SCTLR sctlr;

        SCR scr;

        CPSR cpsr;

        union
        {
            TTBCR ttbcr; // AArch32 translations
            TCR tcr;     // AArch64 translations
        };

        HTCR htcr;

        HCR  hcr;

        VTCR_t vtcr;

        bool isWrite;

        bool isFetch;

        SecurityState ss;
        bool secureLookup = false;

        PASpace ipaSpace;

        bool isUncacheable;

        struct LongDescData
        {
            bool rwTable = false;
            bool userTable = false;
            bool xnTable = false;
            bool pxnTable = false;
        };
        std::optional<LongDescData> longDescData;

        bool hpd;
 
        uint8_t sh;
        uint8_t irgn;
        uint8_t orgn;

        bool stage2Req;

        BaseMMU::Translation *stage2Tran;

        bool timing;

        bool functional;

        BaseMMU::Mode mode;

        MMU::ArmTranslationType tranType;

        L1Descriptor l1Desc;
        L2Descriptor l2Desc;

        LongDescriptor longDesc;

        bool delayed;
 
        TableWalker *tableWalker;

        Tick startTime;

        unsigned levels;
 
        void doL1Descriptor();
        void doL2Descriptor();
 
        void doLongDescriptor();
 
        WalkerState();
 
        std::string name() const { return tableWalker->name(); }
    };
 
    class TableWalkerState : public Packet::SenderState
    {
      public:
        Tick delay = 0;
        Event *event = nullptr;
    };
 
    class Port : public QueuedRequestPort
    {
      public:
        Port(TableWalker& _walker);
 
        void sendFunctionalReq(const RequestPtr &req, uint8_t *data);
        void sendAtomicReq(const RequestPtr &req, uint8_t *data, Tick delay);
        void sendTimingReq(const RequestPtr &req, uint8_t *data, Tick delay,
            Event *event);
 
        bool recvTimingResp(PacketPtr pkt) override;
 
      private:
        void handleRespPacket(PacketPtr pkt, Tick delay=0);
        void handleResp(TableWalkerState *state, Addr addr,
                        Addr size, Tick delay=0);
 
        PacketPtr createPacket(const RequestPtr &req, uint8_t *data,
                               Tick delay, Event *event);
 
      private:
        TableWalker& owner;

        ReqPacketQueue reqQueue;

        SnoopRespPacketQueue snoopRespQueue;
    };

    class Stage2Walk : public BaseMMU::Translation
    {
      private:
        uint8_t      *data;
        int          numBytes;
        RequestPtr   req;
        Event        *event;
        TableWalker  &parent;
        Addr         oVAddr;
        BaseMMU::Mode mode;
        MMU::ArmTranslationType tranType;
 
      public:
        Fault fault;
 
        Stage2Walk(TableWalker &_parent, uint8_t *_data, Event *_event,
                   Addr vaddr, BaseMMU::Mode mode,
                   MMU::ArmTranslationType tran_type);
 
        void markDelayed() {}
 
        void finish(const Fault &fault, const RequestPtr &req,
            ThreadContext *tc, BaseMMU::Mode mode);
 
        void
        setVirt(Addr vaddr, int size, Request::Flags flags,
                int requestorId)
        {
            numBytes = size;
            req->setVirt(vaddr, size, flags, requestorId, 0);
        }
 
        void translateTiming(ThreadContext *tc);
    };
 
    Fault readDataUntimed(ThreadContext *tc, Addr vaddr, Addr desc_addr,
                          uint8_t *data, int num_bytes, Request::Flags flags,
                          BaseMMU::Mode mode, MMU::ArmTranslationType tran_type,
                          bool functional);
    void readDataTimed(ThreadContext *tc, Addr desc_addr,
                       Stage2Walk *translation, int num_bytes,
                       Request::Flags flags);
 
  protected:

    std::list<WalkerState *> stateQueues[LookupLevel::Num_ArmLookupLevel];

    std::list<WalkerState *> pendingQueue;

    MMU *mmu;

    RequestorID requestorId;

    Port* port;

    const bool isStage2;

    TLB *tlb;

    SCTLR sctlr;
 
    WalkerState *currState;

    bool pending;

    unsigned numSquashable;

    const ArmRelease *release;
    uint8_t _physAddrRange;
    bool _haveLargeAsid64;

    struct TableWalkerStats : public statistics::Group
    {
        TableWalkerStats(statistics::Group *parent);
        statistics::Scalar walks;
        statistics::Scalar walksShortDescriptor;
        statistics::Scalar walksLongDescriptor;
        statistics::Vector walksShortTerminatedAtLevel;
        statistics::Vector walksLongTerminatedAtLevel;
        statistics::Scalar squashedBefore;
        statistics::Scalar squashedAfter;
        statistics::Histogram walkWaitTime;
        statistics::Histogram walkServiceTime;
        // Essentially "L" of queueing theory
        statistics::Histogram pendingWalks;
        statistics::Vector pageSizes;
        statistics::Vector2d requestOrigin;
    } stats;
 
    mutable unsigned pendingReqs;
    mutable Tick pendingChangeTick;
 
    static const unsigned REQUESTED = 0;
    static const unsigned COMPLETED = 1;
 
  public:
    PARAMS(ArmTableWalker);
    TableWalker(const Params &p);
    virtual ~TableWalker();
 
    bool haveLargeAsid64() const { return _haveLargeAsid64; }
    uint8_t physAddrRange() const { return _physAddrRange; }
    void completeDrain();
    DrainState drain() override;
    void drainResume() override;
 
    gem5::Port &getPort(const std::string &if_name,
                    PortID idx=InvalidPortID) override;
 
    Port &getTableWalkerPort();
 
    Fault walk(const RequestPtr &req, ThreadContext *tc,
               uint16_t asid, vmid_t _vmid,
               BaseMMU::Mode mode, BaseMMU::Translation *_trans,
               bool timing, bool functional, SecurityState ss,
               PASpace ipaspace,
               MMU::ArmTranslationType tran_type, bool stage2,
               const TlbEntry *walk_entry);
 
    void setMmu(MMU *_mmu);
    void setTlb(TLB *_tlb) { tlb = _tlb; }
    TLB* getTlb() { return tlb; }
    void memAttrs(ThreadContext *tc, TlbEntry &te, SCTLR sctlr,
                  uint8_t texcb, bool s);
    void memAttrsLPAE(ThreadContext *tc, TlbEntry &te,
                      LongDescriptor &lDescriptor);
    void memAttrsAArch64(ThreadContext *tc, TlbEntry &te,
                         LongDescriptor &lDescriptor);
    void memAttrsWalkAArch64(TlbEntry &te);
    bool uncacheableFromAttrs(uint8_t attrs);
 
    static LookupLevel toLookupLevel(uint8_t lookup_level_as_int);
 
  private:
 
    void doL1Descriptor();
    void doL1DescriptorWrapper();
    EventFunctionWrapper doL1DescEvent;
 
    void doL2Descriptor();
    void doL2DescriptorWrapper();
    EventFunctionWrapper doL2DescEvent;
 
    void doLongDescriptor();
 
    void doL0LongDescriptorWrapper();
    EventFunctionWrapper doL0LongDescEvent;
    void doL1LongDescriptorWrapper();
    EventFunctionWrapper doL1LongDescEvent;
    void doL2LongDescriptorWrapper();
    EventFunctionWrapper doL2LongDescEvent;
    void doL3LongDescriptorWrapper();
    EventFunctionWrapper doL3LongDescEvent;
 
    void doLongDescriptorWrapper(LookupLevel curr_lookup_level);
    Event* LongDescEventByLevel[4];
 
    void fetchDescriptor(Addr desc_addr,
        DescriptorBase &descriptor, int num_bytes,
        Request::Flags flags, LookupLevel lookup_lvl, Event *event,
        void (TableWalker::*doDescriptor)());
 
    Fault generateLongDescFault(ArmFault::FaultSource src);
 
    void insertTableEntry(DescriptorBase &descriptor, bool longDescriptor);
    void insertPartialTableEntry(LongDescriptor &descriptor);

    std::tuple<Addr, Addr, LookupLevel> walkAddresses(
        Addr ttbr, GrainSize tg, int tsz, int pa_range);
 
    Fault processWalk();
    Fault processWalkLPAE();
 
    Addr maxTxSz(GrainSize tg) const;
    Addr s1MinTxSz(GrainSize tg) const;
    bool s1TxSzFault(GrainSize tg, int tsz) const;
    bool checkVAOutOfRange(Addr addr, int top_bit,
        int tsz, bool low_range);

    bool checkAddrSizeFaultAArch64(Addr addr, int pa_range);

    bool uncacheableWalk() const;
 
    Fault processWalkAArch64();
    void processWalkWrapper();
    EventFunctionWrapper doProcessEvent;
 
    void nextWalk(ThreadContext *tc);
 
    void pendingChange();

    void stashCurrState(int queue_idx);
 
    static uint8_t pageSizeNtoStatBin(uint8_t N);
 
    void mpamTagTableWalk(RequestPtr &req) const;
 
  public: /* Testing */
    TlbTestInterface *test;
 
    void setTestInterface(TlbTestInterface *ti);
 
    Fault testWalk(const RequestPtr &walk_req, DomainType domain,
                   LookupLevel lookup_level);
};
 
} // namespace ArmISA
} // namespace gem5
 
#endif //__ARCH_ARM_TABLE_WALKER_HH__