Store the stack inside a thread

kernel/src/thread/Scheduler.cpp

@@ -29,6 +29,8 @@ namespace Scheduler
         Stack idle_stack{idle_stack_vm, ARCH_PAGE_SIZE};
         g_idle.set_sp(idle_stack.top());
 
+        g_idle.stack = idle_stack;
+
         kinfoln("CREATED IDLE THREAD: id %lu with ip %lx and sp %lx", g_idle.id, g_idle.ip(), g_idle.sp());
 
         g_current = &g_idle;
@@ -56,6 +58,8 @@ namespace Scheduler
         Stack thread_stack{thread_stack_vm, ARCH_PAGE_SIZE * 4};
         thread->set_sp(thread_stack.top());
 
+        thread->stack = thread_stack;
+
         g_threads.append(thread);
 
         kinfoln("CREATED THREAD: id %lu with ip %lx and sp %lx", thread->id, thread->ip(), thread->sp());

kernel/src/thread/Thread.h

@@ -2,6 +2,7 @@
 
 #include <luna/LinkedList.h>
 #include <luna/Result.h>
+#include <luna/Stack.h>
 
 #ifdef ARCH_X86_64
 #include "arch/x86_64/CPU.h"
@@ -29,6 +30,8 @@ struct Thread : public DoublyLinkedListNode<Thread>
     u64 ticks_left;
     u64 sleep_ticks_left;
 
+    Stack stack;
+
     ThreadState state = ThreadState::Runnable;
 
     bool is_idle()

luna/include/luna/Stack.h

@@ -3,6 +3,7 @@
 
 struct Stack
 {
+    Stack() = default;
     Stack(u64 base, usize bytes);
 
     u64 bottom()