MIPS: Consolidate TLB related faults.

Pass in a bool to indicate if the fault is from a store instead of having two
different classes. The classes were also misleadingly named since loads are
also processed by the DTB but should return ITB faults since they aren't
stores. The TLB may be returning the wrong fault in this case, but I haven't
looked at it closely.

3 files changed, 23 insertions, 117 deletions

diff --git a/src/arch/mips/faults.cc b/src/arch/mips/faults.cc
index 038b73883..c69bd1bd3 100644
--- a/src/arch/mips/faults.cc
+++ b/src/arch/mips/faults.cc
@@ -85,17 +85,11 @@ template <> FaultVals MipsFault<TrapFault>::vals =
 template <> FaultVals MipsFault<BreakpointFault>::vals =
     { "Breakpoint", 0x0180 };
 
-template <> FaultVals MipsFault<ItbInvalidFault>::vals =
-    { "Invalid TLB Entry Exception (I-Fetch/LW)", 0x0180 };
+template <> FaultVals MipsFault<TlbInvalidFault>::vals =
+    { "Invalid TLB Entry Exception", 0x0180 };
 
-template <> FaultVals MipsFault<ItbRefillFault>::vals =
-    { "TLB Refill Exception (I-Fetch/LW)", 0x0180 };
-
-template <> FaultVals MipsFault<DtbInvalidFault>::vals =
-    { "Invalid TLB Entry Exception (Store)", 0x0180 };
-
-template <> FaultVals MipsFault<DtbRefillFault>::vals =
-    { "TLB Refill Exception (Store)", 0x0180 };
+template <> FaultVals MipsFault<TlbRefillFault>::vals =
+    { "TLB Refill Exception", 0x0180 };
 
 template <> FaultVals MipsFault<TLBModifiedFault>::vals =
     { "TLB Modified Exception", 0x0180 };
@@ -199,9 +193,10 @@ BreakpointFault::invoke(ThreadContext *tc, StaticInstPtr inst)
 }
 
 void
-DtbInvalidFault::invoke(ThreadContext *tc, StaticInstPtr inst)
+TlbInvalidFault::invoke(ThreadContext *tc, StaticInstPtr inst)
 {
     DPRINTF(MipsPRA, "%s encountered.\n", name());
+    setExceptionState(tc, store ? 0x3 : 0x2);
 
     tc->setMiscRegNoEffect(MISCREG_BADVADDR, badVAddr);
     EntryHiReg entryHi = tc->readMiscReg(MISCREG_ENTRYHI);
@@ -213,8 +208,6 @@ DtbInvalidFault::invoke(ThreadContext *tc, StaticInstPtr inst)
     ContextReg context = tc->readMiscReg(MISCREG_CONTEXT);
     context.badVPN2 = contextBadVPN2;
     tc->setMiscRegNoEffect(MISCREG_CONTEXT, context);
-    setExceptionState(tc, 0x3);
-
 
     // Set new PC
     Addr HandlerBase;
@@ -238,66 +231,11 @@ AddressErrorFault::invoke(ThreadContext *tc, StaticInstPtr inst)
 }
 
 void
-ItbInvalidFault::invoke(ThreadContext *tc, StaticInstPtr inst)
-{
-    DPRINTF(MipsPRA, "%s encountered.\n", name());
-    setExceptionState(tc, 0x2);
-    tc->setMiscRegNoEffect(MISCREG_BADVADDR, badVAddr);
-    EntryHiReg entryHi = tc->readMiscReg(MISCREG_ENTRYHI);
-    entryHi.asid = entryHiAsid;
-    entryHi.vpn2 = entryHiVPN2;
-    entryHi.vpn2x = entryHiVPN2X;
-    tc->setMiscRegNoEffect(MISCREG_ENTRYHI, entryHi);
-
-    ContextReg context = tc->readMiscReg(MISCREG_CONTEXT);
-    context.badVPN2 = contextBadVPN2;
-    tc->setMiscRegNoEffect(MISCREG_CONTEXT, context);
-
-
-    // Set new PC
-    Addr HandlerBase;
-    // Offset 0x180 - General Exception Vector
-    HandlerBase = vect() + tc->readMiscReg(MISCREG_EBASE);
-    setHandlerPC(HandlerBase,tc);
-    DPRINTF(MipsPRA, "Exception Handler At: %x , EPC set to %x\n",
-            HandlerBase, tc->readMiscReg(MISCREG_EPC));
-}
-
-void
-ItbRefillFault::invoke(ThreadContext *tc, StaticInstPtr inst)
+TlbRefillFault::invoke(ThreadContext *tc, StaticInstPtr inst)
 {
     DPRINTF(MipsPRA, "%s encountered (%x).\n", name(), MISCREG_BADVADDR);
-    Addr HandlerBase;
-    tc->setMiscRegNoEffect(MISCREG_BADVADDR, badVAddr);
-    EntryHiReg entryHi = tc->readMiscReg(MISCREG_ENTRYHI);
-    entryHi.asid = entryHiAsid;
-    entryHi.vpn2 = entryHiVPN2;
-    entryHi.vpn2x = entryHiVPN2X;
-    tc->setMiscRegNoEffect(MISCREG_ENTRYHI, entryHi);
-    ContextReg context = tc->readMiscReg(MISCREG_CONTEXT);
-    context.badVPN2 = contextBadVPN2;
-    tc->setMiscRegNoEffect(MISCREG_CONTEXT, context);
-
-    StatusReg status = tc->readMiscReg(MISCREG_STATUS);
-    // Since handler depends on EXL bit, must check EXL bit before setting it!!
-    // See MIPS ARM Vol 3, Revision 2, Page 38
-    if (status.exl == 1) {
-        // Offset 0x180 - General Exception Vector
-        HandlerBase = vect() + tc->readMiscReg(MISCREG_EBASE);
-    } else {
-        // Offset 0x000
-        HandlerBase = tc->readMiscReg(MISCREG_EBASE);
-    }
+    setExceptionState(tc, store ? 0x3 : 0x2);
 
-    setExceptionState(tc, 0x2);
-    setHandlerPC(HandlerBase, tc);
-}
-
-void
-DtbRefillFault::invoke(ThreadContext *tc, StaticInstPtr inst)
-{
-    // Set new PC
-    DPRINTF(MipsPRA, "%s encountered.\n", name());
     Addr HandlerBase;
     tc->setMiscRegNoEffect(MISCREG_BADVADDR, badVAddr);
     EntryHiReg entryHi = tc->readMiscReg(MISCREG_ENTRYHI);
@@ -305,7 +243,6 @@ DtbRefillFault::invoke(ThreadContext *tc, StaticInstPtr inst)
     entryHi.vpn2 = entryHiVPN2;
     entryHi.vpn2x = entryHiVPN2X;
     tc->setMiscRegNoEffect(MISCREG_ENTRYHI, entryHi);
-
     ContextReg context = tc->readMiscReg(MISCREG_CONTEXT);
     context.badVPN2 = contextBadVPN2;
     tc->setMiscRegNoEffect(MISCREG_CONTEXT, context);
@@ -313,16 +250,13 @@ DtbRefillFault::invoke(ThreadContext *tc, StaticInstPtr inst)
     StatusReg status = tc->readMiscReg(MISCREG_STATUS);
     // Since handler depends on EXL bit, must check EXL bit before setting it!!
     // See MIPS ARM Vol 3, Revision 2, Page 38
-    if (status.exl) {
+    if (status.exl == 1) {
         // Offset 0x180 - General Exception Vector
         HandlerBase = vect() + tc->readMiscReg(MISCREG_EBASE);
     } else {
         // Offset 0x000
         HandlerBase = tc->readMiscReg(MISCREG_EBASE);
     }
-
-    setExceptionState(tc, 0x3);
-
     setHandlerPC(HandlerBase, tc);
 }
 
diff --git a/src/arch/mips/faults.hh b/src/arch/mips/faults.hh
index 0b3d6ce30..dfb3b4ab5 100644
--- a/src/arch/mips/faults.hh
+++ b/src/arch/mips/faults.hh
@@ -199,27 +199,13 @@ class BreakpointFault : public MipsFault<BreakpointFault>
 #endif
 };
 
-class ItbRefillFault : public MipsFault<ItbRefillFault>
-{
-  public:
-    ItbRefillFault(Addr asid, Addr vaddr, Addr vpn)
-    {
-        entryHiAsid = asid;
-        entryHiVPN2 = vpn >> 2;
-        entryHiVPN2X = vpn & 0x3;
-        badVAddr = vaddr;
-        contextBadVPN2 = vpn >> 2;
-    }
-#if FULL_SYSTEM
-    void invoke(ThreadContext * tc,
-            StaticInstPtr inst = StaticInst::nullStaticInstPtr);
-#endif
-};
-
-class DtbRefillFault : public MipsFault<DtbRefillFault>
+class TlbRefillFault : public MipsFault<TlbRefillFault>
 {
+  protected:
+    bool store;
   public:
-    DtbRefillFault(Addr asid, Addr vaddr, Addr vpn)
+    TlbRefillFault(Addr asid, Addr vaddr, Addr vpn, bool _store) :
+        store(_store)
     {
         entryHiAsid = asid;
         entryHiVPN2 = vpn >> 2;
@@ -233,10 +219,13 @@ class DtbRefillFault : public MipsFault<DtbRefillFault>
 #endif
 };
 
-class ItbInvalidFault : public MipsFault<ItbInvalidFault>
+class TlbInvalidFault : public MipsFault<TlbInvalidFault>
 {
+  protected:
+    bool store;
   public:
-    ItbInvalidFault(Addr asid, Addr vaddr, Addr vpn)
+    TlbInvalidFault(Addr asid, Addr vaddr, Addr vpn, bool _store) :
+        store(_store)
     {
         entryHiAsid = asid;
         entryHiVPN2 = vpn >> 2;
@@ -267,23 +256,6 @@ class TLBModifiedFault : public MipsFault<TLBModifiedFault>
 #endif
 };
 
-class DtbInvalidFault : public MipsFault<DtbInvalidFault>
-{
-  public:
-    DtbInvalidFault(Addr asid, Addr vaddr, Addr vpn)
-    {
-        entryHiAsid = asid;
-        entryHiVPN2 = vpn >> 2;
-        entryHiVPN2X = vpn & 0x3;
-        badVAddr = vaddr;
-        contextBadVPN2 = vpn >> 2;
-    }
-#if FULL_SYSTEM
-    void invoke(ThreadContext * tc,
-            StaticInst::StaticInstPtr inst = nullStaticInstPtr);
-#endif
-};
-
 class DspStateDisabledFault : public MipsFault<DspStateDisabledFault>
 {
   public:
diff --git a/src/arch/mips/tlb.cc b/src/arch/mips/tlb.cc
index 1336ee7d0..31595b53d 100644
--- a/src/arch/mips/tlb.cc
+++ b/src/arch/mips/tlb.cc
@@ -352,7 +352,7 @@ TLB::translateInst(RequestPtr req, ThreadContext *tc)
           }
 
           if (Valid == false) {
-              return new ItbInvalidFault(Asid, vaddr, vpn);
+              return new InvalidFault(Asid, vaddr, vpn, false);
           } else {
               // Ok, this is really a match, set paddr
               Addr PAddr;
@@ -368,7 +368,7 @@ TLB::translateInst(RequestPtr req, ThreadContext *tc)
             }
         } else {
             // Didn't find any match, return a TLB Refill Exception
-            return new ItbRefillFault(Asid, vaddr, vpn);
+            return new RefillFault(Asid, vaddr, vpn, false);
         }
     }
     return checkCacheability(req);
@@ -447,7 +447,7 @@ TLB::translateData(RequestPtr req, ThreadContext *tc, bool write)
             }
 
             if (Valid == false) {
-                return new DtbInvalidFault(Asid, vaddr, VPN);
+                return new InvalidFault(Asid, vaddr, VPN, true);
             } else {
                 // Ok, this is really a match, set paddr
                 if (!Dirty) {
@@ -466,7 +466,7 @@ TLB::translateData(RequestPtr req, ThreadContext *tc, bool write)
             }
         } else {
             // Didn't find any match, return a TLB Refill Exception
-            return new DtbRefillFault(Asid, vaddr, VPN);
+            return new RefillFault(Asid, vaddr, VPN, true);
         }
     }
     return checkCacheability(req);