Trait PageTableEntryTrait

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pub trait PageTableEntryTrait:
    Clone
    + Copy
    + Debug
    + Default
    + Pod
    + PodOnce
    + Sized
    + Send
    + Sync
    + 'static {
    // Required methods
    fn is_present(&self) -> bool;
    fn new_page(paddr: Paddr, level: PagingLevel, prop: PageProperty) -> Self;
    fn new_pt(paddr: Paddr) -> Self;
    fn paddr(&self) -> Paddr;
    fn prop(&self) -> PageProperty;
    fn set_prop(&mut self, prop: PageProperty);
    fn is_last(&self, level: PagingLevel) -> bool;

    // Provided methods
    fn new_absent() -> Self { ... }
    fn as_usize(self) -> usize { ... }
    fn from_usize(pte_raw: usize) -> Self { ... }
}

Expand description

A trait that abstracts architecture-specific page table entries (PTEs).

Note that a default PTE should be a PTE that points to nothing.

Required Methods§

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fn is_present(&self) -> bool

Returns if the PTE points to something.

For PTEs created by Self::new_absent, this method should return false. For PTEs created by Self::new_page or Self::new_pt and modified with Self::set_prop, this method should return true.

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fn new_page(paddr: Paddr, level: PagingLevel, prop: PageProperty) -> Self

Creates a new PTE that maps to a page.

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fn new_pt(paddr: Paddr) -> Self

Creates a new PTE that maps to a child page table.

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fn paddr(&self) -> Paddr

Returns the physical address from the PTE.

The physical address recorded in the PTE is either:

the physical address of the next-level page table, or
the physical address of the page that the PTE maps to.

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fn prop(&self) -> PageProperty

Returns the page property of the PTE.

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fn set_prop(&mut self, prop: PageProperty)

Sets the page property of the PTE.

This methold has an impact only if the PTE is present. If not, this method will do nothing.

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fn is_last(&self, level: PagingLevel) -> bool

Returns if the PTE maps a page rather than a child page table.

The method needs to know the level of the page table where the PTE resides, since architectures like x86-64 have a huge bit only in intermediate levels.