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//! Functions to flush the translation lookaside buffer (TLB).
use core::arch::asm;
/// Invalidate the given address in the TLB using the `invlpg` instruction.
///
/// # Safety
/// This function is unsafe as it causes a general protection fault (GP) if the current privilege
/// level is not 0.
pub unsafe fn flush(addr: usize) {
asm!("invlpg ({})", in(reg) addr, options(att_syntax, nostack, preserves_flags));
}
/// Invalidate the TLB completely by reloading the CR3 register.
///
/// # Safety
/// This function is unsafe as it causes a general protection fault (GP) if the current privilege
/// level is not 0.
pub unsafe fn flush_all() {
use crate::controlregs::{cr3, cr3_write};
cr3_write(cr3())
}
#[cfg(all(test, feature = "vmtest"))]
mod x86testing {
use super::*;
use x86test::*;
#[x86test]
fn check_flush_all() {
unsafe {
flush_all();
}
}
#[x86test]
fn check_flush() {
// A better test would be:
// map page, read page, unmap page, read page, flush, read page -> pfault
unsafe {
flush(0xdeadbeef);
}
}
}