Make Hyp Timer !Send

Author: jonathanpallant

aarch32-cpu/src/generic_timer/el2.rs

@@ -1,5 +1,7 @@
 //! Code and types for Generic Timer support at EL2 on Armv8-R.
 
+use core::marker::PhantomData;
+
 use crate::register;
 
 use super::{El1PhysicalTimer, El1VirtualTimer, GenericTimer};
@@ -160,18 +162,30 @@ impl GenericTimer for El2VirtualTimer {
     }
 }
 
-/// Represents our Hypervisor-specific Physical Timer when we are running at EL1.
-pub struct El2HypPhysicalTimer();
+/// Represents our Hypervisor-specific Physical Timer.
+///
+/// This is designed for use by a hypervisor, whilst an EL1 application
+/// concurrently uses the Physical Timer and/or the Virtual Timer.
+///
+/// This type is not [Send] because it is a per-core type and should not be moved across
+/// cores on an SMP system.
+pub struct El2HypPhysicalTimer {
+    _phantom: PhantomData<*const u8>,
+}
 
 impl El2HypPhysicalTimer {
     /// Create a Timer handle for the EL2-specific Hyp Physical Timer.
     ///
     /// # Safety
     ///
     /// Only create one of these at any given time, as they access shared
-    /// mutable state within the processor and do read-modify-writes on that state.
+    /// mutable state within the processor and do read-modify-writes on that
+    /// state. This timer is distinct from the Physical Timer and the Virtual
+    /// Timer, and so can exist concurrently.
     pub unsafe fn new() -> El2HypPhysicalTimer {
-        El2HypPhysicalTimer()
+        El2HypPhysicalTimer {
+            _phantom: PhantomData,
+        }
     }
 }