Method unmap

src/memory/paging/mapper.rs:103–124

Unmaps the given page and adds all freed frames to the given `FrameAllocator`.

(&mut self, page: Page, allocator: &mut A)

    /// Unmaps the given page and adds all freed frames to the given `FrameAllocator`.
    pub fn unmap<A>(&mut self, page: Page, allocator: &mut A)
        where A: FrameAllocator
    {
        use x86_64::VirtualAddress;
        use x86_64::instructions::tlb;

        assert!(self.translate(page.start_address()).is_some());

        let p1 = self.p4_mut()
            .next_table_mut(page.p4_index())
            .and_then(|p3| p3.next_table_mut(page.p3_index()))
            .and_then(|p2| p2.next_table_mut(page.p2_index()))
            .expect("mapping code does not support huge pages");
        let frame = p1[page.p1_index()].pointed_frame().unwrap();
        p1[page.p1_index()].set_unused();

        // flush page address from the TLB
        tlb::flush(VirtualAddress(page.start_address()));

        // TODO free p(1,2,3) table if empty
        // allocator.deallocate_frame(frame);
    }
}