Struct Smap 

pub struct Smap(());

A helper type that provides SMAP related methods.

This type can only be instantiated if SMAP is supported by the CPU.

Tuple Fields

0: ()

Implementations

impl Smap

pub fn new() -> Option<Smap>

Checks if the CPU supports SMAP and returns a Smap instance if supported or None if not.

This function uses CPUID to determine if SMAP is supported by the CPU.

Note that this function does not check whether SMAP has be enabled in CR4.

pub const unsafe fn new_unchecked() -> Smap

Returns a Smap instance.

Safety

The caller must ensure that the CPU supports SMAP.

pub fn is_enabled(self) -> bool

Returns whether the RFlags::ALIGNMENT_CHECK flag is unset.

Note that SMAP also requires [Cr4Flags::SUPERVISOR_MODE_ACCESS_PREVENTION] to be set. This function does not check CR4 because doing so is much slower than just checking the AC flag.

pub fn disable(self)

Disable SMAP access checks by setting RFlags::ALIGNMENT_CHECK using the stac instruction.

This will do nothing if SMAP access checks are already disabled.

pub fn enable(self)

Enable SMAP access checks by clearing RFlags::ALIGNMENT_CHECK using the clac instruction.

This will do nothing if SMAP access checks are already enabled.

pub fn without_smap<F, R>(self, f: F) -> R

where F: FnOnce() -> R,

Call a closure with SMAP disabled.

This function disables SMAP before calling the closure and restores the SMAP state afterwards.

Trait Implementations

impl Clone for Smap

fn clone(&self) -> Smap

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Smap

impl Debug for Smap

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

Formats the value using the given formatter.