enable static threads

Author: mjs513

Diff for: cores/arduino/main.cpp

@@ -9,10 +9,19 @@
 #include <zephyr/llext/symbol.h>
 #endif
 
+#ifdef CONFIG_MULTITHREADING
+void start_static_threads();
+#endif
+
 int main(void) {
 #if (DT_NODE_HAS_PROP(DT_PATH(zephyr_user), cdc_acm) && CONFIG_USB_CDC_ACM)
   Serial.begin(115200);
 #endif
+
+#ifdef CONFIG_MULTITHREADING
+  start_static_threads();
+#endif
+
   setup();
 
   for (;;) {

Diff for: cores/arduino/threads.cpp

@@ -0,0 +1,26 @@
+#include "Arduino.h"
+
+#ifdef CONFIG_MULTITHREADING
+void start_static_threads() {
+    #define _FOREACH_STATIC_THREAD(thread_data) \
+        STRUCT_SECTION_FOREACH(_static_thread_data, thread_data)
+
+    _FOREACH_STATIC_THREAD(thread_data) {
+        k_thread_create(thread_data->init_thread, thread_data->init_stack, thread_data->init_stack_size, thread_data->init_entry,
+                        thread_data->init_p1, thread_data->init_p2, thread_data->init_p3, thread_data->init_prio,
+                        thread_data->init_options, thread_data->init_delay);
+        k_thread_name_set(thread_data->init_thread, thread_data->init_name);
+        thread_data->init_thread->init_data = thread_data;
+    }
+
+    /*
+    * Take a sched lock to prevent them from running
+    * until they are all started.
+    */
+    k_sched_lock();
+    _FOREACH_STATIC_THREAD(thread_data) {
+        k_thread_start(thread_data->init_thread);
+    }
+    k_sched_unlock();
+}
+#endif

Diff for: loader/llext_exports.c

@@ -48,6 +48,8 @@ EXPORT_SYMBOL(isupper);
 EXPORT_SYMBOL(islower);
 EXPORT_SYMBOL(isxdigit);
 
+EXPORT_SYMBOL(k_sched_lock);
+EXPORT_SYMBOL(k_sched_unlock);
 
 #if defined(CONFIG_USB_DEVICE_STACK)
 EXPORT_SYMBOL(usb_enable);

Diff for: variants/llext/linker_script.ld

@@ -34,6 +34,10 @@ SECTIONS {
         KEEP (*(.ctors))
         KEEP (*(.dtors))
         KEEP (*(.fini))
+
+        __static_thread_data_list_start = .;
+        KEEP(*(SORT_BY_NAME(.__static_thread_data.static.*)));
+        __static_thread_data_list_end = .;
     }
 
     .rodata : {