commit d57b8ba34ef233855688fcba824679fcdcaceeef
author Adrian Herrera <adrian.herrera@arm.com> Wed Oct 09 17:58:19 2019 +0100
committer Giacomo Travaglini <giacomo.travaglini@arm.com> Tue Nov 05 09:27:30 2019 +0000
tree 3eeb4b84f8d41603544333976d9fb3cfc73976ac
parent 0a276fb4bb41f43ada306248e3d9a80e0a7e8140

dev-arm: optional instantiation of GICv3 ITS

GICv3 ITS is an optional component of GICv3. The previous behaviour
was for a stub ITS to be created by default, which resulted in a crash
for use cases where a GICv3 with no ITS is required.
This patch removes the instantiation of the ITS by default and adds
checks for its presence both in initialization and device tree
generation code.

Change-Id: Id424924c8c1152d512aaa2837de4aa60329ec234
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22423
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/arm/Gic.py

diff --git a/src/dev/arm/Gic.py b/src/dev/arm/Gic.py
index eec6e95..20b7bca 100644
--- a/src/dev/arm/Gic.py
+++ b/src/dev/arm/Gic.py
@@ -203,7 +203,7 @@
     # Used for DTB autogeneration
     _state = FdtState(addr_cells=2, size_cells=2, interrupt_cells=3)
 
-    its = Param.Gicv3Its(Gicv3Its(), "GICv3 Interrupt Translation Service")
+    its = Param.Gicv3Its(NULL, "GICv3 Interrupt Translation Service")
 
     dist_addr = Param.Addr("Address for distributor")
     dist_pio_delay = Param.Latency('10ns', "Delay for PIO r/w to distributor")
@@ -263,7 +263,8 @@
 
         node.appendPhandle(self)
 
-        # Generate the ITS device tree
-        node.append(self.its.generateDeviceTree(self._state))
+        # Generate the ITS device tree if instantiated
+        if self.its != NULL:
+            node.append(self.its.generateDeviceTree(self._state))
 
         yield node

src/dev/arm/gic_v3.cc

diff --git a/src/dev/arm/gic_v3.cc b/src/dev/arm/gic_v3.cc
index eb38efe..ba0a8ee 100644
--- a/src/dev/arm/gic_v3.cc
+++ b/src/dev/arm/gic_v3.cc
@@ -91,7 +91,9 @@
         cpuInterfaces[i]->init();
     }
 
-    params()->its->setGIC(this);
+    Gicv3Its *its = params()->its;
+    if (its)
+        its->setGIC(this);
 
     BaseGic::init();
 }