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

crates/adapter-riscv/src/devices/mod.rs

@@ -10,7 +10,9 @@ use types::mapping::PagePerms;
 
 // Boot-time device wiring. Everything here goes through the kernel's
 // mapping API so the kernel knows about every page a driver can touch.
-// P5 replaces these hardcoded grants with capabilities handed to init.
+// Device regions come from the board table and belong to init, which
+// also holds capabilities to them; moving drivers onto those caps is
+// userspace work.
 
 fn kern() -> &'static mut kernel::Kernel<crate::platform::RiscVPlatform> {
     unsafe { &mut *crate::kernel_ptr() }
@@ -23,11 +25,16 @@ fn pages(uart: &Uart, n: usize) -> PageCount {
         .unwrap_or_else(|| crate::halt(uart, "bad page count"))
 }
 
-/// Maps device MMIO at `pa` into `pid` at `va`.
+/// Maps the board device region at `pa` into `pid` at `va`. The region
+/// belongs to init (see `kernel::Kernel::register_board`); `n` must match
+/// its size.
 pub(crate) fn map_mmio(uart: &Uart, pid: ProcessId, va: usize, pa: usize, n: usize) {
     let id = kern()
-        .create_device_region(pid, PhysicalAddress::from_raw(pa), pages(uart, n))
-        .unwrap_or_else(|_| crate::halt(uart, "device region failed"));
+        .device_region_at(PhysicalAddress::from_raw(pa))
+        .unwrap_or_else(|| crate::halt(uart, "no such board device"));
+    if kern().region_pages(id).map(|p| p.value() as usize) != Some(n) {
+        crate::halt(uart, "device size mismatch");
+    }
     kern()
         .map_region(id, pid, VirtualAddress::from_raw(va), PagePerms::ReadWrite)
         .unwrap_or_else(|_| crate::halt(uart, "device map failed"));