refactor: tasks code cleanup

src/task/tcb.rs

@@ -1,16 +1,22 @@
 use crate::{
     arch::ThreadContext,
     memory::{AddressSpace, KernelStack, VirtualAddr},
-    println,
 };
 
 // Thread Control Block
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum ExitReason {
+    Exited(usize),
+    Killed,
+    Fault,
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum ThreadState {
     Ready,
     Running,
     Blocked,
-    Dead,
+    Dead(ExitReason),
 }
 
 #[derive(Debug)]
@@ -41,32 +47,3 @@ impl Tcb {
         }
     }
 }
-
-pub unsafe fn run_first_user(user_tcb: &Tcb) {
-    let previous_interrupts = crate::arch::disable_interrupts_and_save();
-
-    let mut boot_thread_ctx = ThreadContext::empty();
-    unsafe {
-        user_tcb.address_space.activate();
-        crate::arch::set_kernel_stack(user_tcb.kernel_stack.top());
-        crate::arch::switch_context(&mut boot_thread_ctx, &user_tcb.context);
-    }
-
-    crate::arch::restore_interrupts(previous_interrupts);
-}
-
-pub unsafe fn switch(prev: &mut Tcb, next: &Tcb) {
-    let previous_interrupts = crate::arch::disable_interrupts_and_save();
-
-    if prev.address_space != next.address_space {
-        unsafe { next.address_space.activate() };
-    }
-
-    crate::arch::set_kernel_stack(next.kernel_stack.top());
-
-    unsafe {
-        crate::arch::switch_context(&mut prev.context, &next.context);
-    }
-
-    crate::arch::restore_interrupts(previous_interrupts);
-}