Add a proper vfs driver into the kernel which handles file operations,

fix munmap number, remove the draw calls, make address space an option,
copy only the top 256 bytes of the HHDM and map the ELF code inside
userspace, add safe copying from userspace

kernel/src/task/scheduler.rs

@@ -39,7 +39,7 @@ impl Locked<Scheduler> {
         let mut guard = without_interrupts(|| self.lock());
         let pid = guard.next_pid;
         guard.next_pid += 1;
-        let process = Process::new(pid, entry_point, stack_top, heap_base, heap_base)?;
+        let process = Process::new(pid, entry_point, stack_top, heap_base, heap_base);
         guard.processes.insert(pid, process);
 
         Some(pid)
@@ -52,7 +52,6 @@ impl Locked<Scheduler> {
         };
 
         set_current_pid(Some(pid));
-
         enter_usermode(entry_point as u64, (stack_top & !0xF) - 8);
     }