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authorAndreas Sandberg <Andreas.Sandberg@ARM.com>2013-01-07 13:05:44 -0500
committerAndreas Sandberg <Andreas.Sandberg@ARM.com>2013-01-07 13:05:44 -0500
commita7e0cbeb36394eec3960dc0e2fb15377880e9e98 (patch)
tree3aa15e38997aeabd2f39158252687a73a9da2fea
parent901258c22b631cd7c14e564bd5f1cde36347515e (diff)
downloadgem5-a7e0cbeb36394eec3960dc0e2fb15377880e9e98.tar.xz
cpu: Introduce sanity checks when switching between CPUs
This patch introduces the following sanity checks when switching between CPUs: * Check that the set of new and old CPUs do not overlap. Having an overlap between the set of new CPUs and the set of old CPUs is currently not supported. Doing such a switch used to result in the following assertion error: BaseCPU::takeOverFrom(BaseCPU*): \ Assertion `!new_itb_port->isConnected()' failed. * Check that all new CPUs are in the switched out state. * Check that all old CPUs are in the switched in state.
-rw-r--r--src/cpu/BaseCPU.py1
-rw-r--r--src/cpu/base.cc6
-rw-r--r--src/cpu/base.hh12
-rw-r--r--src/python/m5/simulate.py10
4 files changed, 28 insertions, 1 deletions
diff --git a/src/cpu/BaseCPU.py b/src/cpu/BaseCPU.py
index 697be87e1..957203150 100644
--- a/src/cpu/BaseCPU.py
+++ b/src/cpu/BaseCPU.py
@@ -95,6 +95,7 @@ class BaseCPU(MemObject):
code('''
void switchOut();
void takeOverFrom(BaseCPU *cpu);
+ bool switchedOut();
''')
def takeOverFrom(self, old_cpu):
diff --git a/src/cpu/base.cc b/src/cpu/base.cc
index 2b1df6696..b8cd60f63 100644
--- a/src/cpu/base.cc
+++ b/src/cpu/base.cc
@@ -119,6 +119,7 @@ BaseCPU::BaseCPU(Params *p, bool is_checker)
_instMasterId(p->system->getMasterId(name() + ".inst")),
_dataMasterId(p->system->getMasterId(name() + ".data")),
_taskId(ContextSwitchTaskId::Unknown), _pid(Request::invldPid),
+ _switchedOut(p->defer_registration),
interrupts(p->interrupts), profileEvent(NULL),
numThreads(p->numThreads), system(p->system)
{
@@ -356,6 +357,8 @@ BaseCPU::findContext(ThreadContext *tc)
void
BaseCPU::switchOut()
{
+ assert(!_switchedOut);
+ _switchedOut = true;
if (profileEvent && profileEvent->scheduled())
deschedule(profileEvent);
}
@@ -365,8 +368,11 @@ BaseCPU::takeOverFrom(BaseCPU *oldCPU)
{
assert(threadContexts.size() == oldCPU->threadContexts.size());
assert(_cpuId == oldCPU->cpuId());
+ assert(_switchedOut);
+ assert(oldCPU != this);
_pid = oldCPU->getPid();
_taskId = oldCPU->taskId();
+ _switchedOut = false;
ThreadID size = threadContexts.size();
for (ThreadID i = 0; i < size; ++i) {
diff --git a/src/cpu/base.hh b/src/cpu/base.hh
index 6552be0d6..633b7f2a7 100644
--- a/src/cpu/base.hh
+++ b/src/cpu/base.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2011 ARM Limited
+ * Copyright (c) 2011-2012 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@@ -114,6 +114,9 @@ class BaseCPU : public MemObject
* used to generate a taskId */
uint32_t _pid;
+ /** Is the CPU switched out or active? */
+ bool _switchedOut;
+
/**
* Define a base class for the CPU ports (instruction and data)
* that is refined in the subclasses. This class handles the
@@ -321,6 +324,13 @@ class BaseCPU : public MemObject
virtual void takeOverFrom(BaseCPU *cpu);
/**
+ * Determine if the CPU is switched out.
+ *
+ * @return True if the CPU is switched out, false otherwise.
+ */
+ bool switchedOut() const { return _switchedOut; }
+
+ /**
* Number of threads we're actually simulating (<= SMT_MAX_THREADS).
* This is a constant for the duration of the simulation.
*/
diff --git a/src/python/m5/simulate.py b/src/python/m5/simulate.py
index 8ad273225..a30648929 100644
--- a/src/python/m5/simulate.py
+++ b/src/python/m5/simulate.py
@@ -228,11 +228,21 @@ def switchCpus(cpuList):
if not isinstance(item, tuple) or len(item) != 2:
raise RuntimeError, "List must have tuples of (oldCPU,newCPU)"
+ old_cpu_set = set([old_cpu for old_cpu, new_cpu in cpuList])
for old_cpu, new_cpu in cpuList:
if not isinstance(old_cpu, objects.BaseCPU):
raise TypeError, "%s is not of type BaseCPU" % old_cpu
if not isinstance(new_cpu, objects.BaseCPU):
raise TypeError, "%s is not of type BaseCPU" % new_cpu
+ if new_cpu in old_cpu_set:
+ raise RuntimeError, \
+ "New CPU (%s) is in the list of old CPUs." % (old_cpu,)
+ if not new_cpu.switchedOut():
+ raise RuntimeError, \
+ "New CPU (%s) is already active." % (new_cpu,)
+ if old_cpu.switchedOut():
+ raise RuntimeError, \
+ "Old CPU (%s) is inactive." % (new_cpu,)
# Now all of the CPUs are ready to be switched out
for old_cpu, new_cpu in cpuList: