gem5: centralize information on simulate() time reached

userland/posix/pthread_count.c

@@ -1,4 +1,6 @@
 /* count to infinity in n threads.
+ *
+ * https://github.com/cirosantilli/linux-kernel-module-cheat#pthreads
  *
  * Useful if you need to keep several threads around
  * to test something.

userland/posix/pthread_deadlock.c

@@ -0,0 +1,28 @@
+/* Let's see a trivial deadlock in action to feel the joys of multithreading.
+ *
+ * https://github.com/cirosantilli/linux-kernel-module-cheat#pthreads
+ *
+ * Exit successfully immediately without any arguments:
+ *
+ * ./pthread_deadlock.out
+ *
+ * Hang forever in a deadlock if one argument is given:
+ *
+ * ....
+ * ./pthread_deadlock.out 0
+ * ....
+ */
+
+#define _XOPEN_SOURCE 700
+#include <assert.h>
+#include <pthread.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+    pthread_mutex_t main_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
+    (void)(argv);
+    pthread_mutex_lock(&main_thread_mutex);
+    if (argc > 1)
+        pthread_mutex_lock(&main_thread_mutex);
+    return EXIT_SUCCESS;
+}