arch-arm: Create helper for sending events (SEV)

Events can be generated by devices, so we need an interface devices
can use to notify events to PEs.

Change-Id: I330575e7d116388d5f9260ef4400b0feaa861f3e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21301
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/arm/isa/insts/misc.isa

@@ -1,6 +1,6 @@
 // -*- mode:c++ -*-
 
-// Copyright (c) 2010-2013,2017-2018 ARM Limited
+// Copyright (c) 2010-2013,2017-2019 ARM Limited
 // All rights reserved
 //
 // The license below extends only to copyright in the software and shall
@@ -784,11 +784,9 @@ let {{
         ThreadContext *oc = sys->getThreadContext(x);
         if (oc == xc->tcBase())
             continue;
+
         // Wake CPU with interrupt if they were sleeping
-        if (oc->readMiscReg(MISCREG_SEV_MAILBOX) == 0) {
-            // Post Interrupt and wake cpu if needed
-            oc->getCpuPtr()->postInterrupt(oc->threadId(), INT_SEV, 0);
-        }
+        sendEvent(oc);
     }
     '''
     sevIop = InstObjParams("sev", "SevInst", "PredOp", \

src/arch/arm/utility.cc

@@ -192,6 +192,15 @@ copyRegs(ThreadContext *src, ThreadContext *dest)
     dynamic_cast<TLB *>(dest->getDTBPtr())->invalidateMiscReg();
 }
 
+void
+sendEvent(ThreadContext *tc)
+{
+    if (tc->readMiscReg(MISCREG_SEV_MAILBOX) == 0) {
+        // Post Interrupt and wake cpu if needed
+        tc->getCpuPtr()->postInterrupt(tc->threadId(), INT_SEV, 0);
+    }
+}
+
 bool
 inSecureState(ThreadContext *tc)
 {

src/arch/arm/utility.hh

@@ -117,6 +117,10 @@ copyMiscRegs(ThreadContext *src, ThreadContext *dest)
 
 void initCPU(ThreadContext *tc, int cpuId);
 
+/** Send an event (SEV) to a specific PE if there isn't
+ * already a pending event */
+void sendEvent(ThreadContext *tc);
+
 static inline bool
 inUserMode(CPSR cpsr)
 {