feat(kernel): WatchDeath + SetTimer events as notification signals; adapter wakes at earliest deadline

crates/libkos/src/syscall/notify.rs

@@ -56,3 +56,22 @@ pub fn ack_interrupt(irq: CapSlot) -> Result<()> {
     )
     .map(|_| ())
 }
+
+/// Signals `notification` when the process behind `process` dies.
+pub fn watch_death(process: CapSlot, notification: CapSlot) -> Result<()> {
+    raw(
+        SYS_WATCH_DEATH,
+        [process.value() as usize, notification.value() as usize, 0, 0, 0, 0],
+    )
+    .map(|_| ())
+}
+
+/// Signals `notification` once `get_time()` reaches `deadline`; replaces
+/// this process's timer. A zero deadline cancels it.
+pub fn set_timer(notification: CapSlot, deadline: types::time::Ticks) -> Result<()> {
+    raw(
+        SYS_SET_TIMER,
+        [notification.value() as usize, deadline.raw() as usize, 0, 0, 0, 0],
+    )
+    .map(|_| ())
+}