refactor(adapter): split trap/page_table/smp/entry by concern; trim comments

crates/adapter-riscv/src/kernel_cell.rs

@@ -7,7 +7,7 @@ pub struct KernelCell<T> {
     inner: UnsafeCell<MaybeUninit<T>>,
 }
 
-// Single-core, interrupts disabled during kernel access.
+// Access is serialized by the kernel lock.
 unsafe impl<T> Sync for KernelCell<T> {}
 
 impl<T> KernelCell<T> {
@@ -18,8 +18,7 @@ impl<T> KernelCell<T> {
         }
     }
 
-    /// Initializes the cell by letting `build` write the value straight
-    /// into its storage, so a large `T` never lives on the stack.
+    /// Initializes in place, so a large `T` never lives on the stack.
     ///
     /// # Safety
     /// `build` must fully initialize the `T` behind the pointer.
@@ -28,9 +27,7 @@ impl<T> KernelCell<T> {
         self.initialized.store(true, Ordering::Release);
     }
 
-    /// Returns a raw pointer to the kernel. Callers must ensure
-    /// no aliasing `&mut` references exist. Safe on single-core
-    /// with interrupts disabled during kernel calls.
+    /// Raw pointer to the kernel; callers must avoid aliasing `&mut`.
     pub fn as_ptr(&self) -> *mut T {
         debug_assert!(self.initialized.load(Ordering::Acquire));
         unsafe { (*self.inner.get()).as_mut_ptr() }