Modularize interrupt handlers, split up scheduler and PIT interrupt handlers

kernel/proc/proc.c

@@ -16,8 +16,9 @@
 #include "std/string.h"
 #include "cpu/gdt.h"
 #include "intr/intr.h"
-#include "switch.h"
+#include "intr/pic.h"
 #include "vmm/vmm.h"
+#include "proc/switch.h"
 #include "elf.h"
 #include "errors.h"
 #include "kprintf.h"
@@ -252,10 +253,18 @@ void proc_killself(void) {
   proc_kill(proc);
 }
 
+int proc_intr(IntrStackFrame *frame) {
+  intr_pic_eoi();
+  proc_sched(frame);
+  return INTR_NOEOI;
+}
+
 void proc_init(void) {
   spinlock_init(&PROCS.spinlock);
   PROCS.procs = NULL;
 
+  intr_attchhandler(&proc_intr, INTR_IRQBASE+0);
+
   Proc *init = proc_spawnuser("base", "/bin/init");
   PROCS.current = init;
   proc_register(init);