arch-arm: Setup TC/ISA at construction time 2nd attempt

This partly reverts commit ec75787aef
by fixing the original problem noted by Bobby (long regressions):

setupThreadContext has to be implemented otherswise the GICv3 cpu interface
will end up holding old references when switching TC/ISAs.

This new implementation is still setting up the cpu interface reference
in the ISA only when it is required, but it is storing the
TC/ISA reference within the interface every time the ISA::setupThreadContext
gets called.

Change-Id: I2f54f95761d63655162c253e887b872f3718c764
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65931
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>

src/arch/arm/isa.cc

@@ -524,15 +524,10 @@ ISA::setupThreadContext()
 
     selfDebug->init(tc);
 
-    Gicv3 *gicv3 = dynamic_cast<Gicv3 *>(system->getGIC());
-    if (!gicv3)
-        return;
-
-    if (!gicv3CpuInterface)
-        gicv3CpuInterface.reset(gicv3->getCPUInterface(tc->contextId()));
-
-    gicv3CpuInterface->setISA(this);
-    gicv3CpuInterface->setThreadContext(tc);
+    if (auto gicv3_ifc = getGICv3CPUInterface(tc); gicv3_ifc) {
+        gicv3_ifc->setISA(this);
+        gicv3_ifc->setThreadContext(tc);
+    }
 }
 
 void
@@ -2008,10 +2003,28 @@ ISA::getGenericTimer()
 BaseISADevice &
 ISA::getGICv3CPUInterface()
 {
-    panic_if(!gicv3CpuInterface, "GICV3 cpu interface is not registered!");
+    if (gicv3CpuInterface)
+        return *gicv3CpuInterface.get();
+
+    auto gicv3_ifc = getGICv3CPUInterface(tc);
+    panic_if(!gicv3_ifc, "The system does not have a GICv3 irq controller\n");
+    gicv3CpuInterface.reset(gicv3_ifc);
+
     return *gicv3CpuInterface.get();
 }
 
+BaseISADevice*
+ISA::getGICv3CPUInterface(ThreadContext *tc)
+{
+    assert(system);
+    Gicv3 *gicv3 = dynamic_cast<Gicv3 *>(system->getGIC());
+    if (gicv3) {
+        return gicv3->getCPUInterface(tc->contextId());
+    } else {
+        return nullptr;
+    }
+}
+
 bool
 ISA::inSecureState() const
 {

src/arch/arm/isa.hh

@@ -116,6 +116,7 @@ namespace ArmISA
 
         BaseISADevice &getGenericTimer();
         BaseISADevice &getGICv3CPUInterface();
+        BaseISADevice *getGICv3CPUInterface(ThreadContext *tc);
 
         RegVal miscRegs[NUM_MISCREGS];
         const RegId *intRegMap;

src/dev/arm/gic_v3.cc

@@ -147,7 +147,7 @@ Gicv3::init()
 
     for (int i = 0; i < threads; i++) {
         redistributors[i] = new Gicv3Redistributor(this, i);
-        cpuInterfaces[i] = new Gicv3CPUInterface(this, i);
+        cpuInterfaces[i] = new Gicv3CPUInterface(this, sys->threads[i]);
     }
 
     distRange = RangeSize(params().dist_addr,

src/dev/arm/gic_v3_cpu_interface.cc

@@ -55,15 +55,19 @@ using namespace ArmISA;
 const uint8_t Gicv3CPUInterface::GIC_MIN_BPR;
 const uint8_t Gicv3CPUInterface::GIC_MIN_BPR_NS;
 
-Gicv3CPUInterface::Gicv3CPUInterface(Gicv3 * gic, uint32_t cpu_id)
+Gicv3CPUInterface::Gicv3CPUInterface(Gicv3 * gic, ThreadContext *_tc)
     : BaseISADevice(),
       gic(gic),
       redistributor(nullptr),
       distributor(nullptr),
-      cpuId(cpu_id)
+      tc(_tc),
+      maintenanceInterrupt(gic->params().maint_int->get(tc)),
+      cpuId(tc->contextId())
 {
     hppi.prio = 0xff;
     hppi.intid = Gicv3::INTID_SPURIOUS;
+
+    setISA(static_cast<ISA*>(tc->getIsaPtr()));
 }
 
 void

src/dev/arm/gic_v3_cpu_interface.hh

@@ -68,10 +68,10 @@ class Gicv3CPUInterface : public ArmISA::BaseISADevice, public Serializable
     Gicv3 * gic;
     Gicv3Redistributor * redistributor;
     Gicv3Distributor * distributor;
-    uint32_t cpuId;
 
-    ArmInterruptPin *maintenanceInterrupt;
     ThreadContext *tc;
+    ArmInterruptPin *maintenanceInterrupt;
+    uint32_t cpuId;
 
     BitUnion64(ICC_CTLR_EL1)
         Bitfield<63, 20> res0_3;
@@ -359,7 +359,7 @@ class Gicv3CPUInterface : public ArmISA::BaseISADevice, public Serializable
     void setBankedMiscReg(ArmISA::MiscRegIndex misc_reg, RegVal val) const;
   public:
 
-    Gicv3CPUInterface(Gicv3 * gic, uint32_t cpu_id);
+    Gicv3CPUInterface(Gicv3 * gic, ThreadContext *tc);
 
     void init();