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Check size and alignment for untyped metadata

This commit is contained in:
Tao Su 2025-11-07 09:35:21 +00:00 committed by Tate, Hongliang Tian
parent 83176020f2
commit 314fbe285a
2 changed files with 17 additions and 5 deletions
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18
ostd/src/mm/frame/meta.rs
View File

@ -82,7 +82,7 @@ pub(in crate::mm) struct MetaSlot {
/// - the implementation can simply cast a `*const MetaSlot`
/// to a `*const AnyFrameMeta` for manipulation;
/// - if the metadata need special alignment, we can provide
/// at most `PAGE_METADATA_ALIGN` bytes of alignment;
/// at most [`FRAME_METADATA_MAX_ALIGN`] bytes of alignment;
/// - the subsequent fields can utilize the padding of the
/// reference count to save space.
///
@ -161,6 +161,17 @@ pub unsafe trait AnyFrameMeta: Any + Send + Sync {
}
}
/// Checks that a frame metadata type has valid size and alignment.
#[macro_export]
macro_rules! check_frame_meta_layout {
($t:ty) => {
$crate::const_assert!(size_of::<$t>() <= $crate::mm::frame::meta::FRAME_METADATA_MAX_SIZE);
$crate::const_assert!(
$crate::mm::frame::meta::FRAME_METADATA_MAX_ALIGN % align_of::<$t>() == 0
);
};
}
/// Makes a structure usable as a frame metadata.
#[macro_export]
macro_rules! impl_frame_meta_for {
@ -169,10 +180,7 @@ macro_rules! impl_frame_meta_for {
// SAFETY: `on_drop` won't read the page.
unsafe impl $crate::mm::frame::meta::AnyFrameMeta for $t {}
$crate::const_assert!(size_of::<$t>() <= $crate::mm::frame::meta::FRAME_METADATA_MAX_SIZE);
$crate::const_assert!(
$crate::mm::frame::meta::FRAME_METADATA_MAX_ALIGN % align_of::<$t>() == 0
);
$crate::check_frame_meta_layout!($t);
};
}

4
ostd/src/mm/frame/untyped.rs
View File

@ -46,6 +46,8 @@ macro_rules! impl_untyped_frame_meta_for {
}
}
impl $crate::mm::frame::untyped::AnyUFrameMeta for $t {}
$crate::check_frame_meta_layout!($t);
};
// Implement with a customized drop function.
($t:ty, $body:expr) => {
@ -60,6 +62,8 @@ macro_rules! impl_untyped_frame_meta_for {
}
}
impl $crate::mm::frame::untyped::AnyUFrameMeta for $t {}
$crate::check_frame_meta_layout!($t);
};
}