dev,arm: remove and recreate timer events around drains

Having timer events stored in checkpoints complicates Kvm
execution.  We change the timer behavior so that it always
deschedules any pending events on a drain() and recreates
them on a drainResume(), thus they will never appear in
checkpoints henceforth.  This pattern of behavior makes
it simpler to handle Kvm execution, where the hardware
performs the timer function directly.

Change-Id: Ia218868c69350d96e923c640634d492b5c19cd3f
Reviewed-on: https://gem5-review.googlesource.com/3541
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/dev/arm/generic_timer.hh b/src/dev/arm/generic_timer.hh
index 3a3895489..3eec1d42e 100644
--- a/src/dev/arm/generic_timer.hh
+++ b/src/dev/arm/generic_timer.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2015 ARM Limited
+ * Copyright (c) 2013, 2015, 2017 ARM Limited
  * All rights reserved.
  *
  * The license below extends only to copyright in the software and shall
@@ -102,7 +102,7 @@ class SystemCounter : public Serializable
 };
 
 /// Per-CPU architected timer.
-class ArchTimer : public Serializable
+class ArchTimer : public Serializable, public Drainable
 {
   public:
     class Interrupt
@@ -188,9 +188,14 @@ class ArchTimer : public Serializable
     /// Returns the value of the counter which this timer relies on.
     uint64_t value() const;
 
+    // Serializable
     void serialize(CheckpointOut &cp) const override;
     void unserialize(CheckpointIn &cp) override;
 
+    // Drainable
+    DrainState drain() override;
+    void drainResume() override;
+
   private:
     // Disable copying
     ArchTimer(const ArchTimer &t);