Introducing macros for defining SchemeId, Pid, ...

kernel/common/int_like.rs

@@ -0,0 +1,108 @@
+//! Helpers used to define types that are backed by integers (typically `usize`),
+//! without compromising safety.
+//!
+//! # Example
+//!
+//! ```
+//! /// Define an opaque type `Pid` backed by a `usize`.
+//! int_like!(Pid, usize);
+//!
+//! const ZERO: Pid = Pid::from(0);
+//! ```
+//!
+//! # Example
+//!
+//! ```
+//! /// Define opaque types `Pid` and `AtomicPid`, backed respectively by a `usize`
+//! /// and a `AtomicUsize`.
+//!
+//! int_like!(Pid, AtomicPid, usize, AtomicUsize);
+//!
+//! const ZERO: Pid = Pid::from(0);
+//! let ATOMIC_PID: AtomicPid = AtomicPid::default();
+//! ```
+
+#[macro_export]
+macro_rules! int_like {
+    ($new_type_name:ident, $backing_type: ident) => {
+        #[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Copy)]
+        pub struct $new_type_name($backing_type);
+
+        impl $new_type_name {
+            pub const fn into(self) -> $backing_type {
+                self.0
+            }
+            pub const fn from(x: $backing_type) -> Self {
+                $new_type_name(x)
+            }
+        }
+    };
+
+    ($new_type_name:ident, $new_atomic_type_name: ident, $backing_type:ident, $backing_atomic_type:ident) => {
+        int_like!($new_type_name, $backing_type);
+
+        /// A mutable holder for T that can safely be shared among threads.
+        /// Runtime equivalent to using `AtomicUsize`, just type-safer.
+        pub struct $new_atomic_type_name {
+            container: $backing_atomic_type,
+        }
+
+        impl $new_atomic_type_name {
+            pub const fn new(x: $new_type_name) -> Self {
+                $new_atomic_type_name {
+                    container: $backing_atomic_type::new(x.into())
+                }
+            }
+            pub const fn default() -> Self {
+                Self::new($new_type_name::from(0))
+            }
+            pub fn load(&self, order: ::core::sync::atomic::Ordering) -> $new_type_name {
+                $new_type_name::from(self.container.load(order))
+            }
+            pub fn store(&self, val: $new_type_name, order: ::core::sync::atomic::Ordering) {
+                self.container.store(val.into(), order)
+            }
+            #[allow(dead_code)]
+            pub fn swap(&self, val: $new_type_name, order: ::core::sync::atomic::Ordering) -> $new_type_name {
+                $new_type_name::from(self.container.swap(val.into(), order))
+            }
+            #[allow(dead_code)]
+            pub fn compare_and_swap(&self, current: $new_type_name, new: $new_type_name, order: ::core::sync::atomic::Ordering) -> $new_type_name {
+                $new_type_name::from(self.container.compare_and_swap(current.into(), new.into(), order))
+            }
+            #[allow(dead_code)]
+            pub fn compare_exchange(&self, current: $new_type_name, new: $new_type_name, success: ::core::sync::atomic::Ordering, failure: ::core::sync::atomic::Ordering) -> ::core::result::Result<$new_type_name, $new_type_name> {
+                match self.container.compare_exchange(current.into(), new.into(), success, failure) {
+                    Ok(result) => Ok($new_type_name::from(result)),
+                    Err(result) => Err($new_type_name::from(result))
+                }
+            }
+            #[allow(dead_code)]
+            pub fn compare_exchange_weak(&self, current: $new_type_name, new: $new_type_name, success: ::core::sync::atomic::Ordering, failure: ::core::sync::atomic::Ordering) -> ::core::result::Result<$new_type_name, $new_type_name> {
+                match self.container.compare_exchange_weak(current.into(), new.into(), success, failure) {
+                    Ok(result) => Ok($new_type_name::from(result)),
+                    Err(result) => Err($new_type_name::from(result))
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+fn test() {
+    use core::mem::size_of;
+    use ::core::sync::atomic::AtomicUsize;
+
+    // Generate type `usize_like`.
+    int_like!(UsizeLike, usize);
+    const ZERO: UsizeLike = UsizeLike::from(0);
+    assert_eq!(size_of::<UsizeLike>(), size_of::<usize>());
+
+
+    // Generate types `usize_like` and `AtomicUsize`.
+    int_like!(UsizeLike2, AtomicUsizeLike, usize, AtomicUsize);
+    assert_eq!(size_of::<UsizeLike2>(), size_of::<usize>());
+    assert_eq!(size_of::<AtomicUsizeLike>(), size_of::<AtomicUsize>());
+}
+
+

kernel/common/mod.rs

@@ -0,0 +1,3 @@
+#[macro_use]
+#[macro_export]
+pub mod int_like;

kernel/lib.rs

@@ -47,6 +47,11 @@ use core::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
 /// Context management
 pub mod context;
 
+#[macro_use]
+/// Shared data structures
+pub mod common;
+
+
 /// ELF file parsing
 #[cfg(all(not(test), target_arch = "x86_64"))]
 pub mod elf;