ARM: Track the current ISA mode using the PC.

src/arch/arm/faults.cc

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2010 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2003-2005 The Regents of The University of Michigan
  * Copyright (c) 2007-2008 The Florida State University
  * All rights reserved.
@@ -95,8 +107,7 @@ ArmFaultBase::invoke(ThreadContext *tc)
     cpsr.it1 = cpsr.it2 = 0;
     cpsr.j = 0;
    
-    if (sctlr.te)
+    cpsr.t = sctlr.te;
-       cpsr.t = 1;
     cpsr.a = cpsr.a | abortDisable();
     cpsr.f = cpsr.f | fiqDisable();
     cpsr.i = 1;
@@ -124,10 +135,12 @@ ArmFaultBase::invoke(ThreadContext *tc)
         panic("unknown Mode\n");
     }
 
-    DPRINTF(Faults, "Invoking Fault: %s cpsr: %#x PC: %#x lr: %#x\n", name(), cpsr,
+    Addr pc = tc->readPC();
-            tc->readPC(), tc->readIntReg(INTREG_LR)); 
+    DPRINTF(Faults, "Invoking Fault: %s cpsr: %#x PC: %#x lr: %#x\n",
-    tc->setPC(getVector(tc));
+            name(), cpsr, pc, tc->readIntReg(INTREG_LR));
-    tc->setNextPC(getVector(tc) + cpsr.t ? 2 : 4 );
+    Addr newPc = getVector(tc) | (sctlr.te ? (ULL(1) << PcTBitShift) : 0);
+    tc->setPC(newPc);
+    tc->setNextPC(newPc + cpsr.t ? 2 : 4 );
 }
 #endif // FULL_SYSTEM
 

src/arch/arm/insts/static_inst.hh

@@ -1,4 +1,17 @@
-/* Copyright (c) 2007-2008 The Florida State University
+/*
+ * Copyright (c) 2010 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Copyright (c) 2007-2008 The Florida State University
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -124,6 +137,14 @@ class ArmStaticInst : public StaticInst
 
         return ((spsr & ~bitMask) | (val & bitMask));
     }
+
+    template<class XC>
+    static void
+    setNextPC(XC *xc, Addr val)
+    {
+        xc->setNextPC((xc->readNextPC() & PcModeMask) |
+                      (val & ~PcModeMask));
+    }
 };
 }
 

src/arch/arm/isa.hh

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2010 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2009 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -127,6 +139,19 @@ namespace ArmISA
         MiscReg
         readMiscReg(int misc_reg, ThreadContext *tc)
         {
+            if (misc_reg == MISCREG_CPSR) {
+                CPSR cpsr = miscRegs[misc_reg];
+                Addr pc = tc->readPC();
+                if (pc & (ULL(1) << PcJBitShift))
+                    cpsr.j = 1;
+                else
+                    cpsr.j = 0;
+                if (pc & (ULL(1) << PcTBitShift))
+                    cpsr.t = 1;
+                else
+                    cpsr.t = 0;
+                return cpsr;
+            }
             return readMiscRegNoEffect(misc_reg);
         }
 
@@ -171,6 +196,14 @@ namespace ArmISA
         {
             if (misc_reg == MISCREG_CPSR) {
                 updateRegMap(val);
+                CPSR cpsr = val;
+                Addr npc = tc->readNextPC() & ~PcModeMask;
+                if (cpsr.j)
+                    npc = npc | (ULL(1) << PcJBitShift);
+                if (cpsr.t)
+                    npc = npc | (ULL(1) << PcTBitShift);
+
+                tc->setNextPC(npc);
             }
             return setMiscRegNoEffect(misc_reg, val);
         }

src/arch/arm/isa/operands.isa

@@ -53,13 +53,16 @@ def operand_types {{
 
 let {{
     maybePCRead = '''
-        ((%(reg_idx)s == PCReg) ? (xc->readPC() + 8) :
+        ((%(reg_idx)s == PCReg) ? ((xc->readPC() & ~PcModeMask) + 8) :
          xc->%(func)s(this, %(op_idx)s))
     '''
     maybePCWrite = '''
-        ((%(reg_idx)s == PCReg) ? xc->setNextPC(%(final_val)s) :
+        ((%(reg_idx)s == PCReg) ? setNextPC(xc, %(final_val)s) :
          xc->%(func)s(this, %(op_idx)s, %(final_val)s))
     '''
+
+    readNPC = 'xc->readNextPC() & ~PcModeMask'
+    writeNPC = 'setNextPC(xc, %(final_val)s)'
 }};
 
 def operands {{
@@ -92,13 +95,12 @@ def operands {{
     #Memory Operand
     'Mem': ('Mem', 'uw', None, ('IsMemRef', 'IsLoad', 'IsStore'), 30),
 
-    'Cpsr': ('ControlReg', 'uw', 'MISCREG_CPSR', None, 40),
+    'Cpsr': ('ControlReg', 'uw', 'MISCREG_CPSR', (None, None, 'IsControl'), 40),
     'Spsr': ('ControlReg', 'uw', 'MISCREG_SPSR', None, 41),
     'Fpsr': ('ControlReg', 'uw', 'MISCREG_FPSR', None, 42),
     'Fpsid': ('ControlReg', 'uw', 'MISCREG_FPSID', None, 43),
     'Fpscr': ('ControlReg', 'uw', 'MISCREG_FPSCR', None, 44),
     'Fpexc': ('ControlReg', 'uw', 'MISCREG_FPEXC', None, 45),
-    'NPC': ('NPC', 'uw', None, (None, None, 'IsControl'), 50),
+    'NPC': ('NPC', 'ud', None, (None, None, 'IsControl'), 50,
-    'NNPC': ('NNPC', 'uw', None, (None, None, 'IsControl'), 51)
+            readNPC, writeNPC),
-
 }};

src/arch/arm/miscregs.hh

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2010 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2009 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -97,6 +109,13 @@ namespace ArmISA
     // integer register to allow renaming.
     static const uint32_t CondCodesMask = 0xF80F0000;
 
+    // These otherwise unused bits of the PC are used to select a mode
+    // like the J and T bits of the CPSR.
+    static const Addr PcJBitShift = 33;
+    static const Addr PcTBitShift = 34;
+    static const Addr PcModeMask = (ULL(1) << PcJBitShift) |
+                                   (ULL(1) << PcTBitShift);
+
     BitUnion32(SCTLR)
         Bitfield<30> te;  // Thumb Exception Enable
         Bitfield<29> afe; // Access flag enable

src/arch/arm/tlb.cc

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2010 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2001-2005 The Regents of The University of Michigan
  * Copyright (c) 2007 MIPS Technologies, Inc.
  * Copyright (c) 2007-2008 The Florida State University
@@ -278,18 +290,20 @@ TLB::regStats()
 Fault
 TLB::translateAtomic(RequestPtr req, ThreadContext *tc, Mode mode)
 {
+    Addr vaddr = req->getVaddr() & ~PcModeMask;
 #if !FULL_SYSTEM
     Process * p = tc->getProcessPtr();
 
-    Fault fault = p->pTable->translate(req);
+    Addr paddr;
-    if(fault != NoFault)
+    if (!p->pTable->translate(vaddr, paddr))
-        return fault;
+        return Fault(new GenericPageTableFault(vaddr));
+    req->setPaddr(paddr);
 
     return NoFault;
 #else
     SCTLR sctlr = tc->readMiscReg(MISCREG_SCTLR);
     if (!sctlr.m) {
-        req->setPaddr(req->getVaddr());
+        req->setPaddr(vaddr);
         return NoFault;
     }
     panic("MMU translation not implemented\n");