py: Implement a simple global interpreter lock.
This makes the VM/runtime thread safe, at the cost of not being able to
run code in parallel.
diff --git a/py/modthread.c b/py/modthread.c
index 930ca45..7efad78 100644
--- a/py/modthread.c
+++ b/py/modthread.c
@@ -146,6 +146,8 @@
} thread_entry_args_t;
STATIC void *thread_entry(void *args_in) {
+ // Execution begins here for a new thread. We do not have the GIL.
+
thread_entry_args_t *args = (thread_entry_args_t*)args_in;
mp_state_thread_t ts;
@@ -154,6 +156,8 @@
mp_stack_set_top(&ts + 1); // need to include ts in root-pointer scan
mp_stack_set_limit(16 * 1024); // fixed stack limit for now
+ MP_THREAD_GIL_ENTER();
+
// signal that we are set up and running
mp_thread_start();
@@ -188,6 +192,8 @@
// signal that we are finished
mp_thread_finish();
+ MP_THREAD_GIL_EXIT();
+
return NULL;
}