Struct memory::PteFlagsArch

pub struct PteFlagsArch(/* private fields */);

Available on x86-64 only.

Page table entry (PTE) flags on x86_64.

Note: items beginning with an underscore _ are not used in Theseus.

The designation of bits in each PageTableEntry is as such:

• Bits [0:8] (inclusive) are reserved by hardware for access flags.
• Bits [9:11] (inclusive) are available for custom OS usage.
• Bits [12:51] (inclusive) are reserved by hardware to hold the physical frame address.
• Bits [52:62] (inclusive) are available for custom OS usage.
• Bit 63 is reserved by hardware for access flags (noexec).

Implementations

impl PteFlagsX86_64

pub const VALID: PteFlagsX86_64 = _

• If set, this page is currently “present” in memory.
• If not set, this page is not in memory, which could mean one of several things:
  • The page is not mapped at all
  • The page has been temporarily paged/swapped to disk
  • The page is waiting to be mapped, i.e., for demand paging.

pub const WRITABLE: PteFlagsX86_64 = _

• If set, this page is writable.
• If not set, this page is read-only.

pub const _USER_ACCESSIBLE: PteFlagsX86_64 = _

• If set, userspace (ring 3) can access this page.
• If not set, only kernelspace (ring 0) can access this page.

This is unused in Theseus because it is a single privilege level OS.

pub const WRITE_THROUGH: PteFlagsX86_64 = _

• If set, writes to this page go directly to memory.
• It not set, writes are first written to the CPU cache, and then written to memory. This is also known as “write-back”.

If the Page Attribute Table (PAT) feature is enabled, this represents the least-significant bit of the 3-bit index into the Page Attribute Table; that index is used to determine the PAT entry that holds the memory caching type that is applied to this page.

pub const PAT_BIT0: PteFlagsX86_64 = _

pub const CACHE_DISABLE: PteFlagsX86_64 = _

• If set, this page’s content is never cached, neither for read nor writes.
• If not set, this page’s content is cached as normal, both for read nor writes.

If the Page Attribute Table (PAT) feature is enabled, this represents the middle bit of the 3-bit index into the Page Attribute Table; that index is used to determine the PAT entry that holds the memory caching type that is applied to this page.

pub const DEVICE_MEMORY: PteFlagsX86_64 = _

An alias for Self::CACHE_DISABLE in order to ease compatibility with aarch64.

pub const PAT_BIT1: PteFlagsX86_64 = _

pub const ACCESSED: PteFlagsX86_64 = _

• The hardware will set this bit when the page is accessed.
• The OS can then clear this bit once it has acknowledged that the page was accessed, if it cares at all about this information.

pub const DIRTY: PteFlagsX86_64 = _

• The hardware will set this bit when the page has been written to.
• The OS can then clear this bit once it has acknowledged that the page was written to, which is primarily useful for paging/swapping to disk.

pub const HUGE_PAGE: PteFlagsX86_64 = _

• If set, this page table entry represents a “huge” page. This bit may be used as follows:
  • For a P4-level PTE, it must be not set.
  • If set for a P3-level PTE, it means this PTE maps a 1GiB huge page.
  • If set for a P2-level PTE, it means this PTE maps a 1MiB huge page.
  • A P1-level PTE cannot map a huge page, so this bit is interpreted as [Self::PAT_FOR_P1] instead.
• If not set, this is a normal 4KiB page mapping.

pub const PAT_BIT2_FOR_P1: PteFlagsX86_64 = _

(For P1-level (lowest level) page tables ONLY): If the Page Attribute Table (PAT) feature is enabled, this represents the most-significant bit of the 3-bit index into the Page Attribute Table; that index is used to determine the PAT entry that holds the memory caching type that is applied to this page.

This cannot be used for PAT index bits in a mid-level (P2 or P3) entry.

pub const _GLOBAL: PteFlagsX86_64 = _

• If set, this page is mapped identically across all address spaces (all root page tables) and doesn’t need to be flushed out of the TLB when switching to another address space (page table).
• If not set, this page is mapped into only one or less than all address spaces, or is mapped differently across different address spaces, and thus be flushed out of the TLB when switching address spaces (page tables).

Note: Theseus is a single address space system, so this flag makes no difference.

pub const EXCLUSIVE: PteFlagsX86_64 = _

See PteFlags::EXCLUSIVE. We use bit 55 because it is available for custom OS usage on both x86_64 and aarch64.

pub const NOT_EXECUTABLE: PteFlagsX86_64 = _

• If set, this page is not executable.
• If not set, this page is executable.

impl PteFlagsX86_64

pub const fn empty() -> PteFlagsX86_64

Get a flags value with all bits unset.

pub const fn all() -> PteFlagsX86_64

Get a flags value with all known bits set.

pub const fn bits(&self) -> u64

Get the underlying bits value.

The returned value is exactly the bits set in this flags value.

pub const fn from_bits(bits: u64) -> Option<PteFlagsX86_64>

Convert from a bits value.

This method will return None if any unknown bits are set.

pub const fn from_bits_truncate(bits: u64) -> PteFlagsX86_64

Convert from a bits value, unsetting any unknown bits.

pub const fn from_bits_retain(bits: u64) -> PteFlagsX86_64

Convert from a bits value exactly.

pub fn from_name(name: &str) -> Option<PteFlagsX86_64>

Get a flags value with the bits of a flag with the given name set.

This method will return None if name is empty or doesn’t correspond to any named flag.

pub const fn is_empty(&self) -> bool

Whether all bits in this flags value are unset.

pub const fn is_all(&self) -> bool

Whether all known bits in this flags value are set.

pub const fn intersects(&self, other: PteFlagsX86_64) -> bool

Whether any set bits in a source flags value are also set in a target flags value.

pub const fn contains(&self, other: PteFlagsX86_64) -> bool

Whether all set bits in a source flags value are also set in a target flags value.

pub fn insert(&mut self, other: PteFlagsX86_64)

The bitwise or (|) of the bits in two flags values.

pub fn remove(&mut self, other: PteFlagsX86_64)

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. remove won’t truncate other, but the ! operator will.

pub fn toggle(&mut self, other: PteFlagsX86_64)

The bitwise exclusive-or (^) of the bits in two flags values.

pub fn set(&mut self, other: PteFlagsX86_64, value: bool)

Call insert when value is true or remove when value is false.

pub const fn intersection(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The bitwise and (&) of the bits in two flags values.

pub const fn union(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The bitwise or (|) of the bits in two flags values.

pub const fn difference(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. difference won’t truncate other, but the ! operator will.

pub const fn symmetric_difference(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The bitwise exclusive-or (^) of the bits in two flags values.

pub const fn complement(self) -> PteFlagsX86_64

The bitwise negation (!) of the bits in a flags value, truncating the result.

impl PteFlagsX86_64

pub const fn iter(&self) -> Iter<PteFlagsX86_64>

Yield a set of contained flags values.

Each yielded flags value will correspond to a defined named flag. Any unknown bits will be yielded together as a final flags value.

pub const fn iter_names(&self) -> IterNames<PteFlagsX86_64>

Yield a set of contained named flags values.

This method is like iter, except only yields bits in contained named flags. Any unknown bits, or bits not corresponding to a contained flag will not be yielded.

impl PteFlagsX86_64

Functions common to PTE flags on all architectures.

pub const fn new() -> PteFlagsX86_64

Returns a new PteFlagsX86_64 with the default value, in which only the NOT_EXECUTABLE bit is set.

pub fn valid(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the VALID bit set or cleared.

• If enable is true, this PTE will be considered “present” and “valid”, meaning that the mapping from this page to a physical frame is valid and that the translation of a virtual address in this page should succeed.
• If enable is false, this PTE will be considered “invalid”, and any attempt to access it for translation purposes will cause a page fault.

pub fn writable(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the WRITABLE bit set or cleared.

• If enable is true, this will be writable.
• If enable is false, this will be read-only.

pub fn executable(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the NOT_EXECUTABLE bit cleared or set.

• If enable is true, this page will be executable (NOT_EXECUTABLE will be cleared).
• If enable is false, this page will be non-executable, which is the default (NOT_EXECUTABLE will be set).

pub fn device_memory(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the DEVICE_MEMORY bit set or cleared.

• If enable is true, this will be non-cacheable device memory.
• If enable is false, this will be “normal” memory, the default.

pub fn exclusive(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the EXCLUSIVE bit set or cleared.

• If enable is true, this page will exclusively map its frame.
• If enable is false, this page will NOT exclusively map its frame.

pub fn accessed(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the ACCESSED bit set or cleared.

Typically this is used to clear the ACCESSED bit, in order to indicate that the OS has “acknowledged” the fact that this page was accessed since the last time it checked.

• If enable is true, this page will be marked as accessed.
• If enable is false, this page will be marked as not accessed.

pub fn dirty(self, enable: bool) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the DIRTY bit set or cleared.

Typically this is used to clear the DIRTY bit, in order to indicate that the OS has “acknowledged” the fact that this page was written to since the last time it checked. This bit is typically set by the hardware.

• If enable is true, this page will be marked as dirty.
• If enable is false, this page will be marked as clean.

pub const fn is_valid(&self) -> bool

pub const fn is_writable(&self) -> bool

pub const fn is_executable(&self) -> bool

pub const fn is_device_memory(&self) -> bool

pub const fn is_dirty(&self) -> bool

pub const fn is_accessed(&self) -> bool

pub const fn is_exclusive(&self) -> bool

impl PteFlagsX86_64

Functions specific to x86_64 PTE flags only.

pub fn adjust_for_higher_level_pte(self) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with its flags adjusted for use in a higher-level page table entry, e.g., P4, P3, P2.

Currently, on x86_64, this does the following:

• Clears the NOT_EXECUTABLE bit.
  • P4, P3, and P2 entries should never set NOT_EXECUTABLE, only the lowest-level P1 entry should.
• Clears the EXCLUSIVE bit.
  • Currently, we do not use the EXCLUSIVE bit for P4, P3, or P2 entries, because another page table frame may re-use it (create another alias to it) without our page table implementation knowing about it.
  • Only P1-level PTEs can map a frame exclusively.
• Clears the PAT index value, as we only support PAT on P1-level PTEs.
• Sets the VALID bit, as every P4, P3, and P2 entry must be valid.

pub fn pat_index(self, pat_slot: u8) -> PteFlagsX86_64

Returns a copy of this PteFlagsX86_64 with the PAT index bits set to the value specifying the given pat_slot.

This sets the following bits:

• PteFlagsX86_64::PAT_BIT0 = Bit 0 of pat_slot
• PteFlagsX86_64::PAT_BIT1 = Bit 1 of pat_slot
• PteFlagsX86_64::PAT_BIT2_FOR_P1 = Bit 2 of pat_slot

The other bits [3:7] of pat_slot are ignored.

pub fn get_pat_index(&self) -> u8

pub const fn is_huge(&self) -> bool

Trait Implementations

impl Binary for PteFlagsX86_64

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl BitAnd<PteFlagsX86_64> for PteFlagsX86_64

fn bitand(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The bitwise and (&) of the bits in two flags values.

type Output = PteFlagsX86_64

The resulting type after applying the & operator.

impl BitAndAssign<PteFlagsX86_64> for PteFlagsX86_64

fn bitand_assign(&mut self, other: PteFlagsX86_64)

The bitwise and (&) of the bits in two flags values.

impl BitOr<PteFlagsX86_64> for PteFlagsX86_64

fn bitor(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The bitwise or (|) of the bits in two flags values.

type Output = PteFlagsX86_64

The resulting type after applying the | operator.

impl BitOrAssign<PteFlagsX86_64> for PteFlagsX86_64

fn bitor_assign(&mut self, other: PteFlagsX86_64)

The bitwise or (|) of the bits in two flags values.

impl BitXor<PteFlagsX86_64> for PteFlagsX86_64

fn bitxor(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The bitwise exclusive-or (^) of the bits in two flags values.

type Output = PteFlagsX86_64

The resulting type after applying the ^ operator.

impl BitXorAssign<PteFlagsX86_64> for PteFlagsX86_64

fn bitxor_assign(&mut self, other: PteFlagsX86_64)

The bitwise exclusive-or (^) of the bits in two flags values.

impl Clone for PteFlagsX86_64

fn clone(&self) -> PteFlagsX86_64

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for PteFlagsX86_64

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for PteFlagsX86_64

See PteFlagsX86_64::new() for what bits are set by default.

fn default() -> PteFlagsX86_64

Returns the “default value” for a type.

impl Extend<PteFlagsX86_64> for PteFlagsX86_64

fn extend<T>(&mut self, iterator: T)where T: IntoIterator<Item = PteFlagsX86_64>,

The bitwise or (|) of the bits in each flags value.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Flags for PteFlagsX86_64

const FLAGS: &'static [Flag<PteFlagsX86_64>] = _

The set of defined flags.

type Bits = u64

The underlying bits type.

fn bits(&self) -> u64

Get the underlying bits value.

fn from_bits_retain(bits: u64) -> PteFlagsX86_64

Convert from a bits value exactly.

fn empty() -> Self

Get a flags value with all bits unset.

fn all() -> Self

Get a flags value with all known bits set.

fn from_bits(bits: Self::Bits) -> Option<Self>

Convert from a bits value.

fn from_bits_truncate(bits: Self::Bits) -> Self

Convert from a bits value, unsetting any unknown bits.

fn from_name(name: &str) -> Option<Self>

Get a flags value with the bits of a flag with the given name set.

fn iter(&self) -> Iter<Self>

Yield a set of contained flags values.

fn iter_names(&self) -> IterNames<Self>

Yield a set of contained named flags values.

fn is_empty(&self) -> bool

Whether all bits in this flags value are unset.

fn is_all(&self) -> bool

Whether all known bits in this flags value are set.

fn intersects(&self, other: Self) -> boolwhere Self: Sized,

Whether any set bits in a source flags value are also set in a target flags value.

fn contains(&self, other: Self) -> boolwhere Self: Sized,

Whether all set bits in a source flags value are also set in a target flags value.

fn insert(&mut self, other: Self)where Self: Sized,

The bitwise or (|) of the bits in two flags values.

fn remove(&mut self, other: Self)where Self: Sized,

The intersection of a source flags value with the complement of a target flags value (&!).

fn toggle(&mut self, other: Self)where Self: Sized,

The bitwise exclusive-or (^) of the bits in two flags values.

fn set(&mut self, other: Self, value: bool)where Self: Sized,

Call [Flags::insert] when value is true or [Flags::remove] when value is false.

fn intersection(self, other: Self) -> Self

The bitwise and (&) of the bits in two flags values.

fn union(self, other: Self) -> Self

The bitwise or (|) of the bits in two flags values.

fn difference(self, other: Self) -> Self

The intersection of a source flags value with the complement of a target flags value (&!).

fn symmetric_difference(self, other: Self) -> Self

The bitwise exclusive-or (^) of the bits in two flags values.

fn complement(self) -> Self

The bitwise negation (!) of the bits in a flags value, truncating the result.

impl From<PteFlags> for PteFlagsX86_64

fn from(general: PteFlags) -> PteFlagsX86_64

Converts to this type from the input type.

impl From<PteFlagsX86_64> for PteFlags

fn from(specific: PteFlagsX86_64) -> PteFlags

Converts to this type from the input type.

impl FromIterator<PteFlagsX86_64> for PteFlagsX86_64

fn from_iter<T>(iterator: T) -> PteFlagsX86_64where T: IntoIterator<Item = PteFlagsX86_64>,

The bitwise or (|) of the bits in each flags value.

impl IntoIterator for PteFlagsX86_64

type Item = PteFlagsX86_64

The type of the elements being iterated over.

type IntoIter = Iter<PteFlagsX86_64>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <PteFlagsX86_64 as IntoIterator>::IntoIter

Creates an iterator from a value.

impl LowerHex for PteFlagsX86_64

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Not for PteFlagsX86_64

fn not(self) -> PteFlagsX86_64

The bitwise negation (!) of the bits in a flags value, truncating the result.

type Output = PteFlagsX86_64

The resulting type after applying the ! operator.

impl Octal for PteFlagsX86_64

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl PartialEq<PteFlagsX86_64> for PteFlagsX86_64

fn eq(&self, other: &PteFlagsX86_64) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Sub<PteFlagsX86_64> for PteFlagsX86_64

fn sub(self, other: PteFlagsX86_64) -> PteFlagsX86_64

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. difference won’t truncate other, but the ! operator will.

type Output = PteFlagsX86_64

The resulting type after applying the - operator.

impl SubAssign<PteFlagsX86_64> for PteFlagsX86_64

fn sub_assign(&mut self, other: PteFlagsX86_64)

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. difference won’t truncate other, but the ! operator will.

impl UpperHex for PteFlagsX86_64

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Copy for PteFlagsX86_64

impl Eq for PteFlagsX86_64

impl StructuralEq for PteFlagsX86_64

impl StructuralPartialEq for PteFlagsX86_64