feat(scheduler): working scheduler

Kernel/Source/Arch/Timer.c

@@ -1,5 +1,9 @@
 #include <Arch/Timer.h>
 #include <Arch/GIC.h>
+#include <OS/Scheduler.h>
+#include <Arch/Exceptions.h>
+
+static volatile UInt64 sTimerCounter = 0;
 
 void TimerInitialize() {
     GICEnableInterrupt(kTimerIRQ);
@@ -12,3 +16,13 @@ void TimerReset(UInt64 interval) {
     __asm__ volatile ("msr cntv_tval_el0, %0" :: "r"(frequency /interval));
     __asm__ volatile ("msr cntv_ctl_el0, %0" :: "r"((UInt64)1));
 }
+
+Address TimerHandler(ExceptionsContext* frame) {
+    sTimerCounter++;
+    TimerReset(kTimerFrequency);
+    return SchedulerNext((Address)frame);
+}
+
+UInt64 TimerGetCounter() {
+    return sTimerCounter;
+}