diff -ruN gnumach-1.8+git20180218/kern/cpu_number.h gnumach-1.8+git20180218~/kern/cpu_number.h
--- gnumach-1.8+git20180218/kern/cpu_number.h	2016-10-02 19:45:20.000000000 +0200
+++ gnumach-1.8+git20180218~/kern/cpu_number.h	2018-06-17 02:13:48.000000000 +0200
@@ -35,9 +35,41 @@
 
 #if	(NCPUS == 1)
 	/* cpu number is always 0 on a single processor system */
-#define	cpu_number()	(0)
+	#define	cpu_number()	(0)
+	#define CPU_L1_SIZE (1 << CPU_L1_SHIFT)
+
+#else
 
 #define CPU_L1_SIZE (1 << CPU_L1_SHIFT)
 
+int apic2kernel[255];
+int cpu_number_start = 0, cpu_number_counter = 0;
+
+static int cpu_number(void) {
+  int eax = 1, ebx = 0, ecx = 0, edx = 0;
+  unsigned int i = 0;
+  int apic_id = 0;
+ 
+  if (!cpu_number_start) {
+    for (i = 0; i < 255; i++) {
+      apic2kernel[i] = -1;
+    }
+    cpu_number_start = 1;
+  }
+ 
+  asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (eax));
+  apic_id = (char) (ebx >> 24) & 0xff;
+  //printf("apic_id = %d\n", apic_id);
+ 
+  if (apic2kernel[apic_id] != -1) {
+    return apic2kernel[apic_id];
+  } else {
+    apic2kernel[apic_id] = cpu_number_counter;
+    cpu_number_counter++;
+  }
+ 
+  return apic2kernel[apic_id];
+}
+
 #endif	/* NCPUS == 1 */
 #endif /* _KERN_CPU_NUMBER_H_ */
diff -ruN gnumach-1.8+git20180218/kern/machine.h gnumach-1.8+git20180218~/kern/machine.h
--- gnumach-1.8+git20180218/kern/machine.h	2016-10-02 19:45:20.000000000 +0200
+++ gnumach-1.8+git20180218~/kern/machine.h	2018-06-17 02:11:40.000000000 +0200
@@ -54,5 +54,6 @@
  *  action_thread() shuts down processors or changes their assignment.
  */
 extern void action_thread_continue (void) __attribute__((noreturn));
+extern void action_thread (void)__attribute__((noreturn));
 
 #endif /* _MACHINE_H_ */
diff -ruN gnumach-1.8+git20180218/kern/sched_prim.h gnumach-1.8+git20180218~/kern/sched_prim.h
--- gnumach-1.8+git20180218/kern/sched_prim.h	2017-06-10 01:26:02.000000000 +0200
+++ gnumach-1.8+git20180218~/kern/sched_prim.h	2018-06-17 02:22:27.000000000 +0200
@@ -185,4 +185,6 @@
 extern void idle_thread(void) __attribute__((noreturn));
 extern void sched_thread(void);
 
+extern void cause_ast_check(processor); /*new*/
+
 #endif	/* _KERN_SCHED_PRIM_H_ */
diff -ruN gnumach-1.8+git20180218/kern/thread.h gnumach-1.8+git20180218~/kern/thread.h
--- gnumach-1.8+git20180218/kern/thread.h	2016-10-02 19:45:20.000000000 +0200
+++ gnumach-1.8+git20180218~/kern/thread.h	2018-06-17 02:23:50.000000000 +0200
@@ -344,6 +344,9 @@
 extern kern_return_t	thread_assign_default(
 	thread_t	thread);
 extern void		stack_collect(void);
+
+extern void cause_ast_check(processor); /*new*/
+
 #endif
 
 /*