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

crates/libkos/src/syscall.rs

@@ -89,8 +89,10 @@ pub fn yield_now() {
     let _ = call0(SYS_YIELD);
 }
 
-pub fn halt() -> ! {
-    let _ = call0(SYS_HALT);
+/// Stops the machine. Needs a SystemControl capability; without one the
+/// call fails and this spins, since there is nothing sensible to return.
+pub fn halt(control: CapSlot) -> ! {
+    let _ = raw(SYS_HALT, [control.value() as usize, 0, 0, 0, 0, 0]);
     loop {}
 }
 
@@ -185,6 +187,12 @@ pub fn map_region(region: CapSlot, va: VirtualAddress, perms: PagePerms) -> Resu
     .map(|_| ())
 }
 
+/// The physical base of the region behind `region`, for programming a
+/// device's DMA. Pool regions are physically contiguous.
+pub fn region_address(region: CapSlot) -> Result<usize> {
+    raw(SYS_REGION_ADDRESS, [region.value() as usize, 0, 0, 0, 0, 0]).map(|r| r[1])
+}
+
 // ---- capabilities ----
 
 pub fn delegate(slot: CapSlot, to: CapSlot, permissions: PermissionSet) -> bool {