feat: tasks

src/task/tcb.rs

@@ -0,0 +1,72 @@
+use crate::{
+    arch::ThreadContext,
+    memory::{AddressSpace, KernelStack, VirtualAddr},
+    println,
+};
+
+// Thread Control Block
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum ThreadState {
+    Ready,
+    Running,
+    Blocked,
+    Dead,
+}
+
+#[derive(Debug)]
+pub struct Tcb {
+    pub id: usize,
+    pub state: ThreadState,
+    pub kernel_stack: KernelStack,
+    pub context: ThreadContext,
+    pub address_space: AddressSpace,
+}
+
+impl Tcb {
+    pub fn new_user(
+        id: usize,
+        address_space: AddressSpace,
+        kernel_stack: KernelStack,
+        user_entry: VirtualAddr,
+        user_stack: VirtualAddr,
+    ) -> Self {
+        let context = ThreadContext::new(user_entry, user_stack, kernel_stack.top());
+
+        Self {
+            id,
+            state: ThreadState::Ready,
+            kernel_stack,
+            context,
+            address_space,
+        }
+    }
+}
+
+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);
+}