feat(kernel): SystemControl cap for halt, board device table + boot caps to init, RegionAddress syscall, idle loop services irqs

crates/domain/src/irq/mod.rs

@@ -30,6 +30,11 @@ impl IrqRoutingTable {
         }
     }
 
+    /// Whether `irq` is a line this table can route.
+    pub fn is_valid(&self, irq: IrqId) -> bool {
+        (irq.raw() as usize) < MAX_IRQS
+    }
+
     /// Routes `irq`, replacing any previous route. Fails for lines beyond
     /// the table.
     pub fn set(&mut self, irq: IrqId, route: IrqRoute) -> bool {

crates/domain/src/resource.rs

@@ -8,4 +8,6 @@ pub enum Resource {
     Process(ProcessId),
     Interrupt(IrqId),
     ProcessCreate,
+    /// Machine-wide controls such as halting; given only to init at boot.
+    SystemControl,
 }

crates/domain/src/syscall.rs

@@ -84,6 +84,11 @@ pub enum Syscall {
         va: VirtualAddress,
         perms: PagePerms,
     },
+    /// The physical base of the region named by `region`, so a driver can
+    /// point a device's DMA at memory it has mapped.
+    RegionAddress {
+        region: CapSlot,
+    },
     /// Removes a capability from the caller's own table.
     DropCap {
         slot: CapSlot,
@@ -104,7 +109,10 @@ pub enum Syscall {
     GetProcessId,
     Yield,
     Exit,
-    Halt,
+    /// Stops the machine; needs a SystemControl capability.
+    Halt {
+        control: CapSlot,
+    },
     CreateEndpoint,
     DebugPutchar {
         byte: u8,