initialise the APs

src/include/stdio/printf.c

@@ -1,11 +1,16 @@
 #include <stdio.h>
+#include <arch/spinlock.h>
+
+static int lock = 0;
 
 __attribute__ ((format (printf, 1, 2))) int printf (const char* format, ...)
 {
+    spinlock_acquire(&lock);
     va_list list;
     va_start (list, format);
     int i = vprintf (format, list);
     va_end (list);
+    spinlock_release(&lock);
     return i;
 
 }