[PATCH 05/10] rust: io: register: make register have a typed base
From: Gary Guo
Date: Tue Jul 21 2026 - 13:06:16 EST
Previously `register!` defined registers can be used on any untyped I/O
regions. With all users specifying their desired register type now,
propagate the specified type and restrict I/O access only when type
matches.
Signed-off-by: Gary Guo <gary@xxxxxxxxxxx>
---
rust/kernel/io/register.rs | 111 ++++++++++++++++++---------------------------
1 file changed, 45 insertions(+), 66 deletions(-)
diff --git a/rust/kernel/io/register.rs b/rust/kernel/io/register.rs
index b0fcfce36c9c..df47c28ba4f4 100644
--- a/rust/kernel/io/register.rs
+++ b/rust/kernel/io/register.rs
@@ -121,10 +121,11 @@
io::IoLoc, //
};
-use super::Region;
-
/// Trait implemented by all registers.
pub trait Register: Sized {
+ /// Base type for this register.
+ type Base: ?Sized;
+
/// Backing primitive type of the register.
type Storage: Into<Self> + From<Self>;
@@ -139,9 +140,9 @@ pub trait FixedRegister: Register {}
/// Allows `()` to be used as the `location` parameter of [`Io::write`](super::Io::write) when
/// passing a [`FixedRegister`] value.
-impl<const SIZE: usize, T> IoLoc<Region<SIZE>, T> for ()
+impl<Base: ?Sized, T> IoLoc<Base, T> for ()
where
- T: FixedRegister,
+ T: FixedRegister<Base = Base>,
{
type IoType = T::Storage;
@@ -153,9 +154,9 @@ fn offset(self) -> usize {
/// A [`FixedRegister`] carries its location in its type. Thus `FixedRegister` values can be used
/// as an [`IoLoc`].
-impl<const SIZE: usize, T> IoLoc<Region<SIZE>, T> for T
+impl<Base: ?Sized, T> IoLoc<Base, T> for T
where
- T: FixedRegister,
+ T: FixedRegister<Base = Base>,
{
type IoType = T::Storage;
@@ -178,9 +179,9 @@ pub const fn new() -> Self {
}
}
-impl<const SIZE: usize, T> IoLoc<Region<SIZE>, T> for FixedRegisterLoc<T>
+impl<Base: ?Sized, T> IoLoc<Base, T> for FixedRegisterLoc<T>
where
- T: FixedRegister,
+ T: FixedRegister<Base = Base>,
{
type IoType = T::Storage;
@@ -249,9 +250,9 @@ const fn offset(self) -> usize {
}
}
-impl<const SIZE: usize, T, B> IoLoc<Region<SIZE>, T> for RelativeRegisterLoc<T, B>
+impl<SuperBase: ?Sized, T, B> IoLoc<SuperBase, T> for RelativeRegisterLoc<T, B>
where
- T: RelativeRegister,
+ T: RelativeRegister<Base = SuperBase>,
B: RegisterBase<T::BaseFamily> + ?Sized,
{
type IoType = T::Storage;
@@ -293,9 +294,9 @@ pub fn try_new(idx: usize) -> Option<Self> {
}
}
-impl<const SIZE: usize, T> IoLoc<Region<SIZE>, T> for RegisterArrayLoc<T>
+impl<Base: ?Sized, T> IoLoc<Base, T> for RegisterArrayLoc<T>
where
- T: RegisterArray,
+ T: RegisterArray<Base = Base>,
{
type IoType = T::Storage;
@@ -380,9 +381,9 @@ pub fn try_at(self, idx: usize) -> Option<RelativeRegisterArrayLoc<T, B>> {
}
}
-impl<const SIZE: usize, T, B> IoLoc<Region<SIZE>, T> for RelativeRegisterArrayLoc<T, B>
+impl<SuperBase: ?Sized, T, B> IoLoc<SuperBase, T> for RelativeRegisterArrayLoc<T, B>
where
- T: RelativeRegisterArray,
+ T: RelativeRegisterArray<Base = SuperBase>,
B: RegisterBase<T::BaseFamily> + ?Sized,
{
type IoType = T::Storage;
@@ -408,9 +409,9 @@ pub trait LocatedRegister<Base: ?Sized> {
fn into_io_op(self) -> (Self::Location, Self::Value);
}
-impl<const SIZE: usize, T> LocatedRegister<Region<SIZE>> for T
+impl<Base: ?Sized, T> LocatedRegister<Base> for T
where
- T: FixedRegister,
+ T: FixedRegister<Base = Base>,
{
type Location = FixedRegisterLoc<Self::Value>;
type Value = T;
@@ -850,37 +851,10 @@ macro_rules! register {
$(=> $alias:ident $(+ $alias_offset:ident)? $([$alias_idx:expr])? )?
{ $($fields:tt)* }
)*
- ) => {
- const _: () = {
- #[allow(unused)]
- fn test_base(_: &$reg_base) {}
- };
-
- $(
- $crate::register!(
- @reg $(#[$attr])* $vis $name ($storage) $([$size $(, stride = $stride)?])?
- $(@ $($base +)? $offset)?
- $(=> $alias $(+ $alias_offset)? $([$alias_idx])? )?
- { $($fields)* }
- );
- )*
- };
-
- // Entry point for the macro, allowing multiple registers to be defined in one call.
- // It matches all possible register declaration patterns to dispatch them to corresponding
- // `@reg` rule that defines a single register.
- (
- $(
- $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
- $([ $size:expr $(, stride = $stride:expr)? ])?
- $(@ $($base:ident +)? $offset:literal)?
- $(=> $alias:ident $(+ $alias_offset:ident)? $([$alias_idx:expr])? )?
- { $($fields:tt)* }
- )*
) => {
$(
$crate::register!(
- @reg $(#[$attr])* $vis $name ($storage) $([$size $(, stride = $stride)?])?
+ @reg [$reg_base] $(#[$attr])* $vis $name ($storage) $([$size $(, stride = $stride)?])?
$(@ $($base +)? $offset)?
$(=> $alias $(+ $alias_offset)? $([$alias_idx])? )?
{ $($fields)* }
@@ -892,22 +866,22 @@ fn test_base(_: &$reg_base) {}
// Creates a register at a fixed offset of the MMIO space.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) @ $offset:literal
+ @reg [$reg_base:ty] $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) @ $offset:literal
{ $($fields:tt)* }
) => {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
- $crate::register!(@io_base $name($storage) @ $offset);
+ $crate::register!(@io_base [$reg_base] $name($storage) @ $offset);
$crate::register!(@io_fixed $(#[$attr])* $vis $name($storage));
};
// Creates an alias register of fixed offset register `alias` with its own fields.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:ident
+ @reg [$reg_base:ty] $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:ident
{ $($fields:tt)* }
) => {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
$crate::register!(
- @io_base $name($storage) @
+ @io_base [$reg_base] $name($storage) @
<$alias as $crate::io::register::Register>::OFFSET
);
$crate::register!(@io_fixed $(#[$attr])* $vis $name($storage));
@@ -915,44 +889,47 @@ fn test_base(_: &$reg_base) {}
// Creates a register at a relative offset from a base address provider.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) @ $base:ident + $offset:literal
+ @reg [$reg_base:ty]
+ $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) @ $base:ident + $offset:literal
{ $($fields:tt)* }
) => {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
- $crate::register!(@io_base $name($storage) @ $offset);
+ $crate::register!(@io_base [$reg_base] $name($storage) @ $offset);
$crate::register!(@io_relative $vis $name($storage) @ $base);
};
// Creates an alias register of relative offset register `alias` with its own fields.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $base:ident + $alias:ident
+ @reg [$reg_base:ty]
+ $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $base:ident + $alias:ident
{ $($fields:tt)* }
) => {
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
- $crate::register!(
- @io_base $name($storage) @ <$alias as $crate::io::register::Register>::OFFSET
+ $crate::register!(@io_base [$reg_base]
+ $name($storage) @ <$alias as $crate::io::register::Register>::OFFSET
);
$crate::register!(@io_relative $vis $name($storage) @ $base);
};
// Creates an array of registers at a fixed offset of the MMIO space.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
+ @reg [$reg_base:ty] $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
[ $size:expr, stride = $stride:expr ] @ $offset:literal { $($fields:tt)* }
) => {
$crate::build_assert::static_assert!(::core::mem::size_of::<$storage>() <= $stride);
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
- $crate::register!(@io_base $name($storage) @ $offset);
+ $crate::register!(@io_base [$reg_base] $name($storage) @ $offset);
$crate::register!(@io_array $vis $name($storage) [ $size, stride = $stride ]);
};
// Shortcut for contiguous array of registers (stride == size of element).
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) [ $size:expr ] @ $offset:literal
+ @reg [$reg_base:ty]
+ $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) [ $size:expr ] @ $offset:literal
{ $($fields:tt)* }
) => {
- $crate::register!(
+ $crate::register!(@reg [$reg_base]
$(#[$attr])* $vis $name($storage) [ $size, stride = ::core::mem::size_of::<$storage>() ]
@ $offset { $($fields)* }
);
@@ -960,7 +937,8 @@ fn test_base(_: &$reg_base) {}
// Creates an alias of register `idx` of array of registers `alias` with its own fields.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:ident [ $idx:expr ]
+ @reg [$reg_base:ty]
+ $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:ident [ $idx:expr ]
{ $($fields:tt)* }
) => {
$crate::build_assert::static_assert!(
@@ -969,7 +947,7 @@ fn test_base(_: &$reg_base) {}
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
$crate::register!(
- @io_base $name($storage) @
+ @io_base [$reg_base] $name($storage) @
<$alias as $crate::io::register::Register>::OFFSET
+ $idx * <$alias as $crate::io::register::RegisterArray>::STRIDE
);
@@ -978,14 +956,14 @@ fn test_base(_: &$reg_base) {}
// Creates an array of registers at a relative offset from a base address provider.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
+ @reg [$reg_base:ty] $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
[ $size:expr, stride = $stride:expr ]
@ $base:ident + $offset:literal { $($fields:tt)* }
) => {
$crate::build_assert::static_assert!(::core::mem::size_of::<$storage>() <= $stride);
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
- $crate::register!(@io_base $name($storage) @ $offset);
+ $crate::register!(@io_base [$reg_base] $name($storage) @ $offset);
$crate::register!(
@io_relative_array $vis $name($storage) [ $size, stride = $stride ] @ $base + $offset
);
@@ -993,10 +971,10 @@ fn test_base(_: &$reg_base) {}
// Shortcut for contiguous array of relative registers (stride == size of element).
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) [ $size:expr ]
+ @reg [$reg_base:ty] $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) [ $size:expr ]
@ $base:ident + $offset:literal { $($fields:tt)* }
) => {
- $crate::register!(
+ $crate::register!(@reg [$reg_base]
$(#[$attr])* $vis $name($storage) [ $size, stride = ::core::mem::size_of::<$storage>() ]
@ $base + $offset { $($fields)* }
);
@@ -1005,7 +983,7 @@ fn test_base(_: &$reg_base) {}
// Creates an alias of register `idx` of relative array of registers `alias` with its own
// fields.
(
- @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
+ @reg [$reg_base:ty] $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
=> $base:ident + $alias:ident [ $idx:expr ] { $($fields:tt)* }
) => {
$crate::build_assert::static_assert!(
@@ -1014,7 +992,7 @@ fn test_base(_: &$reg_base) {}
$crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
$crate::register!(
- @io_base $name($storage) @
+ @io_base [$reg_base] $name($storage) @
<$alias as $crate::io::register::Register>::OFFSET +
$idx * <$alias as $crate::io::register::RegisterArray>::STRIDE
);
@@ -1035,8 +1013,9 @@ fn test_base(_: &$reg_base) {}
};
// Implementations shared by all registers types.
- (@io_base $name:ident($storage:ty) @ $offset:expr) => {
+ (@io_base [$reg_base:ty] $name:ident($storage:ty) @ $offset:expr) => {
impl $crate::io::register::Register for $name {
+ type Base = $reg_base;
type Storage = $storage;
const OFFSET: usize = $offset;
--
2.54.0