stos/amd64: cpu: Default to IRQL_PASSIVE on startup

We cannot be certain that the CR8 register will be zeroed by the time we
have control passed to us, therefore it is wise to set it ourselves.

Signed-off-by: Chloe M. <chloe@mensia.org>

paw/stos/arch/amd64/cpu/init.c

@@ -7,6 +7,7 @@
  */
 
 #include <hal/kpcr.h>
+#include <hal/intr.h>
 #include <ex/trace.h>
 #include <machine/cpuid.h>
 #include <machine/idt.h>
@@ -122,4 +123,11 @@ HalKpcrP1Init(KPCR *Kpcr)
     MdVectorInit();
     MdIdtLoad();
 
+    /* Default to IRQL_PASSIVE */
+    ASMV(
+        "mov %0, %%cr8"
+        :
+        : "r" ((UQUAD)IRQL_PASSIVE)
+        : "memory"
+    );
 }