Struct Pte 

#[repr(transparent)]
pub struct Pte(pub usize);

Page Table Entry (PTE).

This struct represents a Page Table Entry (PTE), the entry of last-level table, in the 4-level page table system for x86_64 architecture. A page table entry typically holds the information about the physical address of a page and various control bits, such as flags indicating whether the page is present, read/write, etc.

The Pte struct in this code provides access to these fields and operations on them. Each entry corresponds to a single page in memory and is used by the kernel to map virtual addresses to physical addresses in the page table.

Tuple Fields

0: usize

Implementations

impl Pte

pub const fn pa(&self) -> Option<Pa>

Get the physical address pointed to by this entry.

This function checks whether the page is present (i.e., if the “P” flag is set in the entry). If the page is present, it extracts the physical address from the entry by clearing the flags bits.

Returns

• Some(Pa) if the page is present, containing the physical address.
• None if the page is not present (i.e., the “P” flag is not set).

pub const fn flags(&self) -> PteFlags

Get the flags associated with this page table entry.

This function extracts the flags from the entry. The flags represent various properties of the page, such as whether the page is present, read-only, user-accessible, etc.

Returns

A PteFlags value representing the flags associated with this entry.

pub fn set_pa(&mut self, pa: Pa) -> Result<&mut Self, PageTableMappingError>

Set the physical address for this entry.

This method updates the physical address of the entry, preserving the current flags (e.g., read/write permissions). It checks that the physical address is aligned to a 4K boundary (the page size), as required by the architecture.

Safety

You must invalidate the corresponding TLB Entry.

Parameters

• pa: The new physical address to set for the entry.

Returns

• Ok(&mut Self) if the address is valid and the update is successful.
• Err(PageTableMappingError::Unaligned) if the provided physical address is not aligned.

Warning

This operation does not modify the flags of the entry.

pub unsafe fn set_flags(&mut self, perm: PteFlags) -> &mut Self

Set the flags for this entry.

This method allows you to update the flags associated with the page. The physical address remains unchanged, but the permission settings (e.g., read/write, user/kernel) can be updated.

Parameters

• perm: The new set of flags to assign to the entry.

Returns

A mutable reference to self, allowing for method chaining.

Safety

You must invalidate the corresponding TLB Entry.

pub unsafe fn clear(&mut self) -> Option<Pa>

Clears the entry.

This method removes any previously set physical address and flags from the entry. If the entry contained a valid physical address before being cleared, that address is returned.

Returns

• Some(Pa): The physical address that was previously stored in the entry, if it existed.
• None: If the entry did not contain a valid physical address.

Safety

You must invalidate the corresponding TLB Entry.

Trait Implementations

impl Clone for Pte

fn clone(&self) -> Pte

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Pte