zephyr: Use constructor for static thread stack

Instead of fully expanding the thread stack initializer in the
kobj_define macro, create a hidden constructor as a const fn.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

zephyr/src/object.rs

@@ -289,13 +289,8 @@ macro_rules! _kobj_stack {
                 unsafe { ::core::mem::zeroed() };
 
             // The proxy object used to ensure initialization is placed in initialized memory.
-            $v static $name: $crate::_export::KStaticThreadStack = $crate::object::StaticKernelObject {
-                value: ::core::cell::UnsafeCell::new($crate::sys::thread::StaticThreadStack {
-                    base: [< $name _REAL >].data.get() as *mut $crate::raw::z_thread_stack_element,
-                    size: $size,
-                }),
-                init: $crate::sync::atomic::AtomicUsize::new(0),
-            };
+            $v static $name: $crate::_export::KStaticThreadStack =
+                $crate::_export::KStaticThreadStack::new_from(&[< $name _REAL >]);
         }
     };
 

zephyr/src/sys/thread.rs

@@ -50,7 +50,7 @@ use zephyr_sys::{
 };
 use super::K_NO_WAIT;
 
-use crate::{align::AlignAs, object::{StaticKernelObject, Wrapped}};
+use crate::{align::AlignAs, object::{StaticKernelObject, Wrapped}, sync::atomic::AtomicUsize};
 
 /// Adjust the stack size for alignment.  Note that, unlike the C code, we don't include the
 /// reservation in this, as it has its own fields in the struct.
@@ -123,6 +123,22 @@ impl Wrapped for StaticKernelObject<StaticThreadStack> {
     }
 }
 
+impl StaticKernelObject<StaticThreadStack> {
+    /// Construct a StaticThreadStack object.
+    ///
+    /// This is not intended to be directly called, but is used by the [`kobj_define`] macro.
+    #[doc(hidden)]
+    pub const fn new_from<const SZ: usize>(real: &RealStaticThreadStack<SZ>) -> Self {
+        Self {
+            value: UnsafeCell::new(StaticThreadStack {
+                base: real.data.get() as *mut z_thread_stack_element,
+                size: SZ,
+            }),
+            init: AtomicUsize::new(0),
+        }
+    }
+}
+
 /// A single Zephyr thread.
 ///
 /// This wraps a `k_thread` type within Rust.  This value is returned from