arch, mem, sim: Consolidate and rename the SE mode page table classes.

Now that Nothing inherits from PageTableBase directly, it can be
merged into FuncPageTable. This change also takes the opportunity to
rename the combined class to EmulationPageTable which lets you know
that it's specifically for SE mode.

Also remove the page table entry cache since it doesn't seem to
actually improve performance. The TLBs likely absorb the majority of
the locality, essentially acting like a cache like they would in real
hardware.

Change-Id: If1bcb91aed08686603bf7bee37298c0eee826e13
Reviewed-on: https://gem5-review.googlesource.com/7342
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

14 files changed, 80 insertions, 198 deletions

diff --git a/src/arch/alpha/process.cc b/src/arch/alpha/process.cc
index 2c6f83309..112abbf4a 100644
--- a/src/arch/alpha/process.cc
+++ b/src/arch/alpha/process.cc
@@ -49,7 +49,8 @@ using namespace AlphaISA;
 using namespace std;
 
 AlphaProcess::AlphaProcess(ProcessParams *params, ObjectFile *objFile)
-    : Process(params, new FuncPageTable(params->name, params->pid, PageBytes),
+    : Process(params,
+              new EmulationPageTable(params->name, params->pid, PageBytes),
       objFile)
 {
     fatal_if(params->useArchPT, "Arch page tables not implemented.");
diff --git a/src/arch/arm/process.cc b/src/arch/arm/process.cc
index aef714ed3..1bb23dec2 100644
--- a/src/arch/arm/process.cc
+++ b/src/arch/arm/process.cc
@@ -63,9 +63,10 @@ using namespace ArmISA;
 
 ArmProcess::ArmProcess(ProcessParams *params, ObjectFile *objFile,
                        ObjectFile::Arch _arch)
-    : Process(params, new FuncPageTable(params->name, params->pid, PageBytes),
+    : Process(params,
+              new EmulationPageTable(params->name, params->pid, PageBytes),
               objFile),
-              arch(_arch)
+      arch(_arch)
 {
     fatal_if(params->useArchPT, "Arch page tables not implemented.");
 }
diff --git a/src/arch/mips/process.cc b/src/arch/mips/process.cc
index 62ccd5afe..b2957e0c4 100644
--- a/src/arch/mips/process.cc
+++ b/src/arch/mips/process.cc
@@ -50,7 +50,8 @@ using namespace std;
 using namespace MipsISA;
 
 MipsProcess::MipsProcess(ProcessParams *params, ObjectFile *objFile)
-    : Process(params, new FuncPageTable(params->name, params->pid, PageBytes),
+    : Process(params,
+              new EmulationPageTable(params->name, params->pid, PageBytes),
               objFile)
 {
     fatal_if(params->useArchPT, "Arch page tables not implemented.");
diff --git a/src/arch/power/process.cc b/src/arch/power/process.cc
index 22627efe5..6561bff4e 100644
--- a/src/arch/power/process.cc
+++ b/src/arch/power/process.cc
@@ -50,7 +50,8 @@ using namespace std;
 using namespace PowerISA;
 
 PowerProcess::PowerProcess(ProcessParams *params, ObjectFile *objFile)
-    : Process(params, new FuncPageTable(params->name, params->pid, PageBytes),
+    : Process(params,
+              new EmulationPageTable(params->name, params->pid, PageBytes),
               objFile)
 {
     fatal_if(params->useArchPT, "Arch page tables not implemented.");
diff --git a/src/arch/riscv/process.cc b/src/arch/riscv/process.cc
index 73df5f50d..b3e98aefb 100644
--- a/src/arch/riscv/process.cc
+++ b/src/arch/riscv/process.cc
@@ -60,8 +60,8 @@ using namespace std;
 using namespace RiscvISA;
 
 RiscvProcess::RiscvProcess(ProcessParams *params, ObjectFile *objFile) :
-        Process(params, new FuncPageTable(params->name, params->pid,
-                                          PageBytes),
+        Process(params,
+                new EmulationPageTable(params->name, params->pid, PageBytes),
                 objFile)
 {
     fatal_if(params->useArchPT, "Arch page tables not implemented.");
diff --git a/src/arch/sparc/process.cc b/src/arch/sparc/process.cc
index 1fcb6cba3..e4cd874bd 100644
--- a/src/arch/sparc/process.cc
+++ b/src/arch/sparc/process.cc
@@ -56,7 +56,8 @@ static const int FirstArgumentReg = 8;
 
 SparcProcess::SparcProcess(ProcessParams *params, ObjectFile *objFile,
                            Addr _StackBias)
-    : Process(params, new FuncPageTable(params->name, params->pid, PageBytes),
+    : Process(params,
+              new EmulationPageTable(params->name, params->pid, PageBytes),
               objFile),
       StackBias(_StackBias)
 {
diff --git a/src/arch/x86/process.cc b/src/arch/x86/process.cc
index bea002d34..52255af7a 100644
--- a/src/arch/x86/process.cc
+++ b/src/arch/x86/process.cc
@@ -99,12 +99,11 @@ static const int NumArgumentRegs32 M5_VAR_USED =
 X86Process::X86Process(ProcessParams *params, ObjectFile *objFile,
                        SyscallDesc *_syscallDescs, int _numSyscallDescs)
     : Process(params, params->useArchPT ?
-                      static_cast<PageTableBase *>(
+                      static_cast<EmulationPageTable *>(
                               new ArchPageTable(params->name, params->pid,
                                                 params->system, PageBytes)) :
-                      static_cast<PageTableBase *>(
-                              new FuncPageTable(params->name, params->pid,
-                                                PageBytes)),
+                      new EmulationPageTable(params->name, params->pid,
+                                             PageBytes),
               objFile),
       syscallDescs(_syscallDescs), numSyscallDescs(_numSyscallDescs)
 {
diff --git a/src/mem/multi_level_page_table.hh b/src/mem/multi_level_page_table.hh
index 952c2b068..10e411eb1 100644
--- a/src/mem/multi_level_page_table.hh
+++ b/src/mem/multi_level_page_table.hh
@@ -100,7 +100,7 @@ class System;
  * @see MultiLevelPageTable
  */
 template <class ISAOps>
-class MultiLevelPageTable : public FuncPageTable
+class MultiLevelPageTable : public EmulationPageTable
 {
     /**
      * ISA specific operations
diff --git a/src/mem/multi_level_page_table_impl.hh b/src/mem/multi_level_page_table_impl.hh
index 702c08c0a..3222f5f11 100644
--- a/src/mem/multi_level_page_table_impl.hh
+++ b/src/mem/multi_level_page_table_impl.hh
@@ -48,7 +48,7 @@ template <class ISAOps>
 MultiLevelPageTable<ISAOps>::MultiLevelPageTable(const std::string &__name,
                                                  uint64_t _pid, System *_sys,
                                                  Addr pageSize)
-    : FuncPageTable(__name, _pid, pageSize), system(_sys),
+    : EmulationPageTable(__name, _pid, pageSize), system(_sys),
     logLevelSize(PageTableLayout),
     numLevels(logLevelSize.size())
 {
@@ -136,7 +136,7 @@ void
 MultiLevelPageTable<ISAOps>::map(Addr vaddr, Addr paddr,
                                  int64_t size, uint64_t flags)
 {
-    FuncPageTable::map(vaddr, paddr, size, flags);
+    EmulationPageTable::map(vaddr, paddr, size, flags);
 
     PortProxy &p = system->physProxy;
 
@@ -165,7 +165,7 @@ template <class ISAOps>
 void
 MultiLevelPageTable<ISAOps>::remap(Addr vaddr, int64_t size, Addr new_vaddr)
 {
-    FuncPageTable::remap(vaddr, size, new_vaddr);
+    EmulationPageTable::remap(vaddr, size, new_vaddr);
 
     PortProxy &p = system->physProxy;
 
@@ -199,7 +199,7 @@ template <class ISAOps>
 void
 MultiLevelPageTable<ISAOps>::unmap(Addr vaddr, int64_t size)
 {
-    FuncPageTable::unmap(vaddr, size);
+    EmulationPageTable::unmap(vaddr, size);
 
     PortProxy &p = system->physProxy;
 
@@ -222,7 +222,7 @@ template <class ISAOps>
 void
 MultiLevelPageTable<ISAOps>::serialize(CheckpointOut &cp) const
 {
-    FuncPageTable::serialize(cp);
+    EmulationPageTable::serialize(cp);
     /** Since, the page table is stored in system memory
      * which is serialized separately, we will serialize
      * just the base pointer
@@ -234,6 +234,6 @@ template <class ISAOps>
 void
 MultiLevelPageTable<ISAOps>::unserialize(CheckpointIn &cp)
 {
-    FuncPageTable::unserialize(cp);
+    EmulationPageTable::unserialize(cp);
     paramIn(cp, "ptable.pointer", basePtr);
 }
diff --git a/src/mem/page_table.cc b/src/mem/page_table.cc
index 4f06c29e8..3854a8ccd 100644
--- a/src/mem/page_table.cc
+++ b/src/mem/page_table.cc
@@ -48,35 +48,29 @@
 using namespace std;
 using namespace TheISA;
 
-FuncPageTable::FuncPageTable(const std::string &__name,
-                             uint64_t _pid, Addr _pageSize)
-        : PageTableBase(__name, _pid, _pageSize)
-{
-}
-
-FuncPageTable::~FuncPageTable()
+EmulationPageTable::~EmulationPageTable()
 {
     for (auto &iter : pTable)
         delete iter.second;
 }
 
 void
-FuncPageTable::map(Addr vaddr, Addr paddr, int64_t size, uint64_t flags)
+EmulationPageTable::map(Addr vaddr, Addr paddr, int64_t size, uint64_t flags)
 {
     bool clobber = flags & Clobber;
     // starting address must be page aligned
     assert(pageOffset(vaddr) == 0);
 
-    DPRINTF(MMU, "Allocating Page: %#x-%#x\n", vaddr, vaddr+ size);
+    DPRINTF(MMU, "Allocating Page: %#x-%#x\n", vaddr, vaddr + size);
 
-    for (; size > 0; size -= pageSize, vaddr += pageSize, paddr += pageSize) {
+    while (size > 0) {
         auto it = pTable.find(vaddr);
         if (it != pTable.end()) {
             if (clobber) {
                 delete it->second;
             } else {
                 // already mapped
-                fatal("FuncPageTable::allocate: addr %#x already mapped",
+                fatal("EmulationPageTable::allocate: addr %#x already mapped",
                       vaddr);
             }
         } else {
@@ -86,13 +80,14 @@ FuncPageTable::map(Addr vaddr, Addr paddr, int64_t size, uint64_t flags)
         it->second = new TheISA::TlbEntry(pid, vaddr, paddr,
                                          flags & Uncacheable,
                                          flags & ReadOnly);
-        eraseCacheEntry(vaddr);
-        updateCache(vaddr, pTable[vaddr]);
+        size -= pageSize;
+        vaddr += pageSize;
+        paddr += pageSize;
     }
 }
 
 void
-FuncPageTable::remap(Addr vaddr, int64_t size, Addr new_vaddr)
+EmulationPageTable::remap(Addr vaddr, int64_t size, Addr new_vaddr)
 {
     assert(pageOffset(vaddr) == 0);
     assert(pageOffset(new_vaddr) == 0);
@@ -100,91 +95,73 @@ FuncPageTable::remap(Addr vaddr, int64_t size, Addr new_vaddr)
     DPRINTF(MMU, "moving pages from vaddr %08p to %08p, size = %d\n", vaddr,
             new_vaddr, size);
 
-    for (; size > 0;
-         size -= pageSize, vaddr += pageSize, new_vaddr += pageSize)
-    {
+    while (size > 0) {
         auto new_it = pTable.find(new_vaddr);
         auto old_it = pTable.find(vaddr);
         assert(old_it != pTable.end() && new_it == pTable.end());
 
         new_it->second = old_it->second;
         pTable.erase(old_it);
-        eraseCacheEntry(vaddr);
         new_it->second->updateVaddr(new_vaddr);
-        updateCache(new_vaddr, new_it->second);
+        size -= pageSize;
+        vaddr += pageSize;
+        new_vaddr += pageSize;
     }
 }
 
 void
-FuncPageTable::getMappings(std::vector<std::pair<Addr, Addr>> *addr_maps)
+EmulationPageTable::getMappings(std::vector<std::pair<Addr, Addr>> *addr_maps)
 {
     for (auto &iter : pTable)
         addr_maps->push_back(make_pair(iter.first, iter.second->pageStart()));
 }
 
 void
-FuncPageTable::unmap(Addr vaddr, int64_t size)
+EmulationPageTable::unmap(Addr vaddr, int64_t size)
 {
     assert(pageOffset(vaddr) == 0);
 
     DPRINTF(MMU, "Unmapping page: %#x-%#x\n", vaddr, vaddr+ size);
 
-    for (; size > 0; size -= pageSize, vaddr += pageSize) {
+    while (size > 0) {
         auto it = pTable.find(vaddr);
         assert(it != pTable.end());
-        eraseCacheEntry(vaddr);
         delete it->second;
         pTable.erase(it);
+        size -= pageSize;
+        vaddr += pageSize;
     }
-
 }
 
 bool
-FuncPageTable::isUnmapped(Addr vaddr, int64_t size)
+EmulationPageTable::isUnmapped(Addr vaddr, int64_t size)
 {
     // starting address must be page aligned
     assert(pageOffset(vaddr) == 0);
 
-    for (; size > 0; size -= pageSize, vaddr += pageSize) {
-        if (pTable.find(vaddr) != pTable.end()) {
+    for (int64_t offset = 0; offset < size; offset += pageSize)
+        if (pTable.find(vaddr + offset) != pTable.end())
             return false;
-        }
-    }
 
     return true;
 }
 
 bool
-FuncPageTable::lookup(Addr vaddr, TheISA::TlbEntry &entry)
+EmulationPageTable::lookup(Addr vaddr, TheISA::TlbEntry &entry)
 {
     Addr page_addr = pageAlign(vaddr);
 
-    if (pTableCache[0].entry && pTableCache[0].vaddr == page_addr) {
-        entry = *pTableCache[0].entry;
-        return true;
-    }
-    if (pTableCache[1].entry && pTableCache[1].vaddr == page_addr) {
-        entry = *pTableCache[1].entry;
-        return true;
-    }
-    if (pTableCache[2].entry && pTableCache[2].vaddr == page_addr) {
-        entry = *pTableCache[2].entry;
-        return true;
-    }
-
     PTableItr iter = pTable.find(page_addr);
 
-    if (iter == pTable.end()) {
+    if (iter == pTable.end())
         return false;
-    }
 
-    updateCache(page_addr, iter->second);
     entry = *iter->second;
     return true;
 }
 
 bool
-PageTableBase::translate(Addr vaddr, Addr &paddr)
+EmulationPageTable::translate(Addr vaddr, Addr &paddr)
 {
     TheISA::TlbEntry entry;
     if (!lookup(vaddr, entry)) {
@@ -197,14 +174,13 @@ PageTableBase::translate(Addr vaddr, Addr &paddr)
 }
 
 Fault
-PageTableBase::translate(RequestPtr req)
+EmulationPageTable::translate(RequestPtr req)
 {
     Addr paddr;
-    assert(pageAlign(req->getVaddr() + req->getSize() - 1)
-           == pageAlign(req->getVaddr()));
-    if (!translate(req->getVaddr(), paddr)) {
+    assert(pageAlign(req->getVaddr() + req->getSize() - 1) ==
+           pageAlign(req->getVaddr()));
+    if (!translate(req->getVaddr(), paddr))
         return Fault(new GenericPageTableFault(req->getVaddr()));
-    }
     req->setPaddr(paddr);
     if ((paddr & (pageSize - 1)) + req->getSize() > pageSize) {
         panic("Request spans page boundaries!\n");
@@ -214,7 +190,7 @@ PageTableBase::translate(RequestPtr req)
 }
 
 void
-FuncPageTable::serialize(CheckpointOut &cp) const
+EmulationPageTable::serialize(CheckpointOut &cp) const
 {
     paramOut(cp, "ptable.size", pTable.size());
 
@@ -229,7 +205,7 @@ FuncPageTable::serialize(CheckpointOut &cp) const
 }
 
 void
-FuncPageTable::unserialize(CheckpointIn &cp)
+EmulationPageTable::unserialize(CheckpointIn &cp)
 {
     int count;
     paramIn(cp, "ptable.size", count);
diff --git a/src/mem/page_table.hh b/src/mem/page_table.hh
index fa584873a..30437a6f9 100644
--- a/src/mem/page_table.hh
+++ b/src/mem/page_table.hh
@@ -49,20 +49,13 @@
 #include "sim/serialize.hh"
 
 class ThreadContext;
-class System;
 
-/**
- * Declaration of base class for page table
- */
-class PageTableBase : public Serializable
+class EmulationPageTable : public Serializable
 {
   protected:
-    struct cacheElement {
-        Addr vaddr;
-        TheISA::TlbEntry *entry;
-    };
-
-    struct cacheElement pTableCache[3];
+    typedef std::unordered_map<Addr, TheISA::TlbEntry *> PTable;
+    typedef PTable::iterator PTableItr;
+    PTable pTable;
 
     const Addr pageSize;
     const Addr offsetMask;
@@ -72,17 +65,15 @@ class PageTableBase : public Serializable
 
   public:
 
-    PageTableBase(const std::string &__name, uint64_t _pid, Addr _pageSize)
-            : pageSize(_pageSize), offsetMask(mask(floorLog2(_pageSize))),
-              pid(_pid), _name(__name)
+    EmulationPageTable(
+            const std::string &__name, uint64_t _pid, Addr _pageSize) :
+            pageSize(_pageSize), offsetMask(mask(floorLog2(_pageSize))),
+            pid(_pid), _name(__name)
     {
         assert(isPowerOf2(pageSize));
-        pTableCache[0].entry = nullptr;
-        pTableCache[1].entry = nullptr;
-        pTableCache[2].entry = nullptr;
     }
 
-    virtual ~PageTableBase() {};
+    virtual ~EmulationPageTable();
 
     /* generic page table mapping flags
      *              unset | set
@@ -99,7 +90,7 @@ class PageTableBase : public Serializable
         ReadOnly    = 8,
     };
 
-    virtual void initState(ThreadContext* tc) = 0;
+    virtual void initState(ThreadContext* tc) {};
 
     // for DPRINTF compatibility
     const std::string name() const { return _name; }
@@ -115,10 +106,9 @@ class PageTableBase : public Serializable
      * @param flags Generic mapping flags that can be set by or-ing values
      *              from MappingFlags enum.
      */
-    virtual void map(Addr vaddr, Addr paddr, int64_t size,
-                     uint64_t flags = 0) = 0;
-    virtual void remap(Addr vaddr, int64_t size, Addr new_vaddr) = 0;
-    virtual void unmap(Addr vaddr, int64_t size) = 0;
+    virtual void map(Addr vaddr, Addr paddr, int64_t size, uint64_t flags = 0);
+    virtual void remap(Addr vaddr, int64_t size, Addr new_vaddr);
+    virtual void unmap(Addr vaddr, int64_t size);
 
     /**
      * Check if any pages in a region are already allocated
@@ -126,14 +116,14 @@ class PageTableBase : public Serializable
      * @param size The length of the region.
      * @return True if no pages in the region are mapped.
      */
-    virtual bool isUnmapped(Addr vaddr, int64_t size) = 0;
+    virtual bool isUnmapped(Addr vaddr, int64_t size);
 
     /**
      * Lookup function
      * @param vaddr The virtual address.
      * @return entry The page table entry corresponding to vaddr.
      */
-    virtual bool lookup(Addr vaddr, TheISA::TlbEntry &entry) = 0;
+    virtual bool lookup(Addr vaddr, TheISA::TlbEntry &entry);
 
     /**
      * Translate function
@@ -157,100 +147,10 @@ class PageTableBase : public Serializable
      */
     Fault translate(RequestPtr req);
 
-    /**
-     * Update the page table cache.
-     * @param vaddr virtual address (page aligned) to check
-     * @param pte page table entry to return
-     * @return A pointer to any entry which is displaced from the cache.
-     */
-    TheISA::TlbEntry *
-    updateCache(Addr vaddr, TheISA::TlbEntry *entry)
-    {
-        TheISA::TlbEntry *evicted = pTableCache[2].entry;
-
-        pTableCache[2].entry = pTableCache[1].entry;
-        pTableCache[2].vaddr = pTableCache[1].vaddr;
-
-        pTableCache[1].entry = pTableCache[0].entry;
-        pTableCache[1].vaddr = pTableCache[0].vaddr;
-
-        pTableCache[0].entry = entry;
-        pTableCache[0].vaddr = vaddr;
-
-        return evicted;
-    }
-
-    /**
-     * Erase an entry from the page table cache.
-     * @param vaddr virtual address (page aligned) to check
-     * @return A pointer to the entry (if any) which is kicked out.
-     */
-    TheISA::TlbEntry *
-    eraseCacheEntry(Addr vaddr)
-    {
-        TheISA::TlbEntry *evicted = nullptr;
-        // Invalidate cached entries if necessary
-        if (pTableCache[0].entry && pTableCache[0].vaddr == vaddr) {
-            evicted = pTableCache[0].entry;
-            pTableCache[0].entry = nullptr;
-        } else if (pTableCache[1].entry && pTableCache[1].vaddr == vaddr) {
-            evicted = pTableCache[1].entry;
-            pTableCache[1].entry = nullptr;
-        } else if (pTableCache[2].entry && pTableCache[2].vaddr == vaddr) {
-            evicted = pTableCache[2].entry;
-            pTableCache[2].entry = nullptr;
-        }
-        return evicted;
-    }
-
-    virtual void getMappings(std::vector<std::pair<Addr, Addr>>
-                             *addr_mappings) {};
-};
-
-/**
- * Declaration of functional page table.
- */
-class FuncPageTable : public PageTableBase
-{
-  private:
-    typedef std::unordered_map<Addr, TheISA::TlbEntry *> PTable;
-    typedef PTable::iterator PTableItr;
-    PTable pTable;
-
-  public:
-
-    FuncPageTable(const std::string &__name, uint64_t _pid, Addr _pageSize);
-
-    ~FuncPageTable();
-
-    void initState(ThreadContext* tc) override
-    {
-    }
-
-    void map(Addr vaddr, Addr paddr, int64_t size,
-             uint64_t flags = 0) override;
-    void remap(Addr vaddr, int64_t size, Addr new_vaddr) override;
-    void unmap(Addr vaddr, int64_t size) override;
-
-    /**
-     * Check if any pages in a region are already allocated
-     * @param vaddr The starting virtual address of the region.
-     * @param size The length of the region.
-     * @return True if no pages in the region are mapped.
-     */
-    bool isUnmapped(Addr vaddr, int64_t size) override;
-
-    /**
-     * Lookup function
-     * @param vaddr The virtual address.
-     * @return entry The page table entry corresponding to vaddr.
-     */
-    bool lookup(Addr vaddr, TheISA::TlbEntry &entry) override;
+    void getMappings(std::vector<std::pair<Addr, Addr>> *addr_mappings);
 
     void serialize(CheckpointOut &cp) const override;
     void unserialize(CheckpointIn &cp) override;
-
-    void getMappings(std::vector<std::pair<Addr, Addr>> *addr_maps) override;
 };
 
 #endif // __MEM_PAGE_TABLE_HH__
diff --git a/src/mem/se_translating_port_proxy.hh b/src/mem/se_translating_port_proxy.hh
index 5ac6b5286..2f2a81b59 100644
--- a/src/mem/se_translating_port_proxy.hh
+++ b/src/mem/se_translating_port_proxy.hh
@@ -47,7 +47,7 @@
 
 #include "mem/port_proxy.hh"
 
-class PageTableBase;
+class EmulationPageTable;
 class Process;
 
 /**
@@ -75,7 +75,7 @@ class SETranslatingPortProxy : public PortProxy
     };
 
   private:
-    PageTableBase *pTable;
+    EmulationPageTable *pTable;
     Process *process;
     AllocType allocating;
 
@@ -83,7 +83,7 @@ class SETranslatingPortProxy : public PortProxy
     SETranslatingPortProxy(MasterPort& port, Process* p, AllocType alloc);
     virtual ~SETranslatingPortProxy();
 
-    void setPageTable(PageTableBase *p) { pTable = p; }
+    void setPageTable(EmulationPageTable *p) { pTable = p; }
     void setProcess(Process *p) { process = p; }
     bool tryReadBlob(Addr addr, uint8_t *p, int size) const;
     bool tryWriteBlob(Addr addr, const uint8_t *p, int size) const;
diff --git a/src/sim/process.cc b/src/sim/process.cc
index 77d7903a7..07c936e76 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -101,7 +101,7 @@
 using namespace std;
 using namespace TheISA;
 
-Process::Process(ProcessParams *params, PageTableBase *pTable,
+Process::Process(ProcessParams *params, EmulationPageTable *pTable,
                  ObjectFile *obj_file)
     : SimObject(params), system(params->system),
       useArchPT(params->useArchPT),
@@ -310,7 +310,8 @@ Process::allocateMem(Addr vaddr, int64_t size, bool clobber)
     int npages = divCeil(size, (int64_t)PageBytes);
     Addr paddr = system->allocPhysPages(npages);
     pTable->map(vaddr, paddr, size,
-                clobber ? PageTableBase::Clobber : PageTableBase::Zero);
+                clobber ? EmulationPageTable::Clobber :
+                          EmulationPageTable::Zero);
 }
 
 void
@@ -405,7 +406,8 @@ bool
 Process::map(Addr vaddr, Addr paddr, int size, bool cacheable)
 {
     pTable->map(vaddr, paddr, size,
-                cacheable ? PageTableBase::Zero : PageTableBase::Uncacheable);
+                cacheable ? EmulationPageTable::Zero :
+                            EmulationPageTable::Uncacheable);
     return true;
 }
 
diff --git a/src/sim/process.hh b/src/sim/process.hh
index 6d465aca9..cb2a3e2be 100644
--- a/src/sim/process.hh
+++ b/src/sim/process.hh
@@ -54,7 +54,7 @@ struct ProcessParams;
 
 class EmulatedDriver;
 class ObjectFile;
-class PageTableBase;
+class EmulationPageTable;
 class SyscallDesc;
 class SyscallReturn;
 class System;
@@ -63,7 +63,7 @@ class ThreadContext;
 class Process : public SimObject
 {
   public:
-    Process(ProcessParams *params, PageTableBase *pTable,
+    Process(ProcessParams *params, EmulationPageTable *pTable,
             ObjectFile *obj_file);
 
     void serialize(CheckpointOut &cp) const override;
@@ -176,7 +176,7 @@ class Process : public SimObject
     bool useArchPT; // flag for using architecture specific page table
     bool kvmInSE;   // running KVM requires special initialization
 
-    PageTableBase* pTable;
+    EmulationPageTable *pTable;
 
     SETranslatingPortProxy initVirtMem; // memory proxy for initial image load