Get rid of the Unallocated thread context state.

Basically merge it in with Halted.
Also had to get rid of a few other functions that
called ThreadContext::deallocate(), including:
 - InOrderCPU's setThreadRescheduleCondition.
 - ThreadContext::exit().  This function was there to avoid terminating
   simulation when one thread out of a multi-thread workload exits, but we
   need to find a better (non-cpu-centric) way.

4 files changed, 25 insertions, 7 deletions

diff --git a/src/sim/process.cc b/src/sim/process.cc
index 4be97f2f6..c45844a51 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -221,7 +221,7 @@ Process::findFreeContext()
     ThreadContext *tc;
     for (int i = 0; i < size; ++i) {
         tc = system->getThreadContext(contextIds[i]);
-        if (tc->status() == ThreadContext::Unallocated) {
+        if (tc->status() == ThreadContext::Halted) {
             // inactive context, free to use
             return tc;
         }
diff --git a/src/sim/syscall_emul.cc b/src/sim/syscall_emul.cc
index 5fe30c269..f0a693db0 100644
--- a/src/sim/syscall_emul.cc
+++ b/src/sim/syscall_emul.cc
@@ -42,6 +42,7 @@
 #include "cpu/base.hh"
 #include "mem/page_table.hh"
 #include "sim/process.hh"
+#include "sim/system.hh"
 
 #include "sim/sim_exit.hh"
 
@@ -91,9 +92,13 @@ SyscallReturn
 exitFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
          ThreadContext *tc)
 {
-    if (tc->exit()) {
+    if (process->system->numRunningContexts() == 1) {
+        // Last running context... exit simulator
         exitSimLoop("target called exit()",
-                process->getSyscallArg(tc, 0) & 0xff);
+                    process->getSyscallArg(tc, 0) & 0xff);
+    } else {
+        // other running threads... just halt this one
+        tc->halt();
     }
 
     return 1;
diff --git a/src/sim/system.cc b/src/sim/system.cc
index d16524c41..f10167bba 100644
--- a/src/sim/system.cc
+++ b/src/sim/system.cc
@@ -211,6 +211,17 @@ System::registerThreadContext(ThreadContext *tc, int assigned)
     return id;
 }
 
+int
+System::numRunningContexts()
+{
+    int running = 0;
+    for (int i = 0; i < _numContexts; ++i) {
+        if (threadContexts[i]->status() != ThreadContext::Halted)
+            ++running;
+    }
+    return running;
+}
+
 void
 System::startup()
 {
diff --git a/src/sim/system.hh b/src/sim/system.hh
index bfa5ea8bb..e1c30490b 100644
--- a/src/sim/system.hh
+++ b/src/sim/system.hh
@@ -89,19 +89,21 @@ class System : public SimObject
     std::vector<ThreadContext *> threadContexts;
     int _numContexts;
 
-    ThreadContext * getThreadContext(int tid)
+    ThreadContext *getThreadContext(int tid)
     {
         return threadContexts[tid];
     }
 
     int numContexts()
     {
-        if (_numContexts != threadContexts.size())
-            panic("cpu array not fully populated!");
-
+        assert(_numContexts == threadContexts.size());
         return _numContexts;
     }
 
+    /** Return number of running (non-halted) thread contexts in
+     * system.  These threads could be Active or Suspended. */
+    int numRunningContexts();
+
 #if FULL_SYSTEM
     Platform *platform;
     uint64_t init_param;