diff --git a/src/memory/mod.rs b/src/memory/mod.rs
new file mode 100644
index 00000000..072d481f
--- /dev/null
+++ b/src/memory/mod.rs
@@ -0,0 +1,77 @@
+use multiboot2::Multiboot;
+use core::iter::range_inclusive;
+use core::cmp::max;
+
+mod paging;
+
+pub fn init(multiboot: &Multiboot) {
+ // ATTENTION: we have a very small stack and no guard page
+
+ let kernel_end = multiboot.elf_tag().unwrap().sections().map(|s| s.addr + s.size).max()
+ .unwrap() as usize;
+ let multiboot_end = multiboot as *const _ as usize + multiboot.total_size as usize;
+ let mut allocator = FrameAllocator::new(max(kernel_end, multiboot_end));
+ let mut c = unsafe{paging::Controller::new(allocator)};
+
+ c.begin_new_table();
+ c.identity_map(Page{number: 0xb8}, true, false);
+
+
+ for section in multiboot.elf_tag().unwrap().sections() {
+ let in_memory = section.flags & 0x2 != 0;
+ let writable = section.flags & 0x1 != 0;
+ let executable = section.flags & 0x4 != 0;
+ if !in_memory {
+ continue;
+ }
+ println!("section at 0x{:x}, allocated: {}, writable: {}, executable: {}", section.addr,
+ in_memory, writable, executable);
+ let start_page = Page::containing_address(section.addr as usize);
+ let end_page = Page::containing_address((section.addr + section.size) as usize);
+ for page in range_inclusive(start_page.number, end_page.number).map(|n| Page{number: n}) {
+ c.identity_map(page, writable, executable);
+ }
+ }
+ c.activate_new_table();
+}
+
+struct VirtualAddress(*const u8);
+
+struct FrameAllocator {
+ next_free_frame: usize,
+}
+
+impl FrameAllocator {
+ fn new(kernel_end: usize) -> FrameAllocator {
+ assert!(kernel_end > 0x100000);
+ FrameAllocator {
+ next_free_frame: ((kernel_end - 1) >> 12) + 1,
+ }
+ }
+
+ fn allocate_frame(&mut self) -> Option {
+ let page_number = self.next_free_frame;
+ self.next_free_frame += 1;
+ Some(Frame {
+ number: page_number
+ })
+ }
+}
+
+#[derive(PartialOrd, Ord, PartialEq, Eq, Clone, Copy)]
+struct Frame {
+ number: usize,
+}
+
+#[derive(PartialOrd, Ord, PartialEq, Eq, Clone, Copy)]
+struct Page {
+ number: usize,
+}
+
+impl Page {
+ fn containing_address(address: usize) -> Page {
+ Page {
+ number: address >> 12,
+ }
+ }
+}
diff --git a/src/memory/paging.rs b/src/memory/paging.rs
new file mode 100644
index 00000000..21a51f4d
--- /dev/null
+++ b/src/memory/paging.rs
@@ -0,0 +1,223 @@
+use super::{VirtualAddress, Frame};
+use core::ops::Deref;
+
+pub type FrameAllocator = super::FrameAllocator;
+pub type Page = super::Page;
+
+pub const PAGE_SIZE: u64 = 4096;
+
+bitflags! {
+ flags PageTableFieldFlags: u64 {
+ const PRESENT = 1 << 0,
+ const WRITABLE = 1 << 1,
+ const USER_ACCESSIBLE = 1 << 2,
+ const WRITE_THROUGH = 1 << 3,
+ const NO_CACHE = 1 << 4,
+ const ACCESSED = 1 << 5,
+ const DIRTY = 1 << 6,
+ const OTHER1 = 1 << 9,
+ const OTHER2 = 1 << 10,
+ const NO_EXECUTE = 1 << 63,
+ }
+}
+
+pub struct Controller {
+ allocator: FrameAllocator,
+}
+
+impl Controller {
+ pub unsafe fn new(allocator: FrameAllocator) -> Controller {
+ Controller {
+ allocator: allocator,
+ }
+ }
+
+ pub fn identity_map(&mut self, page: Page, writable: bool, executable: bool) {
+ let mut flags = PRESENT;
+ if writable {
+ flags = flags | WRITABLE;
+ }
+ if !executable {
+ flags = flags | NO_EXECUTE;
+ }
+
+ page.map_to(Frame{number: page.number}, flags, &mut self.allocator)
+ }
+
+ pub fn begin_new_table(&mut self) {
+ let new_p4_frame = self.allocator.allocate_frame().unwrap();
+ let new_p4_page = &mut PageTablePage(Page{number: new_p4_frame.number});
+ unsafe{new_p4_page.zero()};
+ new_p4_page.field(511).set(new_p4_frame, PRESENT | WRITABLE);
+
+ let old_p4_page = &mut PageTablePage(Page{number: 0o777_777_777_777});
+ old_p4_page.field(511).set(new_p4_frame, PRESENT | WRITABLE);
+
+ Self::flush_tlb();
+ }
+
+ pub fn activate_new_table(&mut self) {
+ unsafe {
+ let p4_address: u64 = {
+ let field = *(0xfffffffffffffff8 as *const u64);
+ field & !0xfff
+ };
+
+ asm!("mov cr3, $0" :: "r"(p4_address) :: "intel")
+ }
+ }
+
+ fn flush_tlb() {
+ unsafe{asm!("mov rax, cr3
+ mov cr3, rax" ::: "{rax}" : "intel")}
+ }
+}
+
+// first allocated address starts on second P4-Page
+pub const FIRST_PAGE : Page = Page {
+ number: 0o_001_000_000_000,
+};
+
+// a page containing a page table
+struct PageTablePage(Page);
+
+struct PageIter(Page);
+
+struct PageTableField(*const u64);
+
+impl Page {
+ fn from_address(address: &VirtualAddress) -> Page {
+ Page {
+ number: address.0 as usize >> 12,
+ }
+ }
+
+ pub fn start_address(&self) -> VirtualAddress {
+ if self.number >= 0o400_000_000_000 {
+ //sign extension
+ VirtualAddress(((self.number << 12) | 0o177777_000_000_000_000_0000) as *const u8)
+ } else {
+ VirtualAddress((self.number << 12) as *const u8)
+ }
+ }
+
+ fn p4_index(&self) -> usize {(self.number >> 27) & 0o777}
+ fn p3_index(&self) -> usize {(self.number >> 18) & 0o777}
+ fn p2_index(&self) -> usize {(self.number >> 9) & 0o777}
+ fn p1_index(&self) -> usize {(self.number >> 0) & 0o777}
+
+ fn p4_page(&self) -> PageTablePage {
+ PageTablePage(Page {
+ number: 0o_777_777_777_777,
+ })
+ }
+ fn p3_page(&self) -> PageTablePage {
+ PageTablePage(Page {
+ number: 0o_777_777_777_000 | self.p4_index(),
+ })
+ }
+ fn p2_page(&self) -> PageTablePage {
+ PageTablePage(Page {
+ number: 0o_777_777_000_000 | (self.p4_index() << 9) | self.p3_index(),
+ })
+ }
+ fn p1_page(&self) -> PageTablePage {
+ PageTablePage(Page {
+ number: 0o_777_000_000_000 | (self.p4_index() << 18) | (self.p3_index() << 9)
+ | self.p2_index(),
+ })
+ }
+
+ pub fn map_to(&self, frame: Frame, flags: PageTableFieldFlags, allocator: &mut FrameAllocator) {
+ let p4_field = self.p4_page().field(self.p4_index());
+ if p4_field.is_free() {
+ p4_field.set(allocator.allocate_frame().expect("no frame allocated"), PRESENT | WRITABLE);
+ unsafe{self.p3_page().zero()};
+ }
+ let p3_field = self.p3_page().field(self.p3_index());
+ if p3_field.is_free() {
+ p3_field.set(allocator.allocate_frame().expect("no frame allocated"), PRESENT | WRITABLE);
+ unsafe{self.p2_page().zero()};
+ }
+ let p2_field = self.p2_page().field(self.p2_index());
+ if p2_field.is_free() {
+ p2_field.set(allocator.allocate_frame().expect("no frame allocated"), PRESENT | WRITABLE);
+ unsafe{self.p1_page().zero()};
+ }
+ let p1_field = self.p1_page().field(self.p1_index());
+ //TODOassert!(p1_field.is_free());
+ p1_field.set(frame, flags);
+ }
+
+ unsafe fn zero(&self) {
+ let page = self.start_address().0 as *mut [u64; (PAGE_SIZE/64) as usize];
+ *page = [0; (PAGE_SIZE/64) as usize];
+ }
+
+ pub fn next_pages(self) -> PageIter {
+ PageIter(self)
+ }
+}
+
+impl Iterator for PageIter {
+ type Item = Page;
+
+ fn next(&mut self) -> Option {
+ self.0.number += 1;
+ Some(self.0)
+ }
+}
+
+impl PageTablePage {
+ fn field(&self, index: usize) -> PageTableField {
+ //print!("index: {} pointer: {:o}\n", index, self.0.start_address().0 as usize + (index * 8));
+ PageTableField((self.0.start_address().0 as usize + (index * 8)) as *const u64)
+ }
+}
+
+impl Deref for PageTablePage {
+ type Target = Page;
+ fn deref(&self) -> &Page { &self.0 }
+}
+
+impl VirtualAddress {
+ pub fn page(&self) -> Page {
+ Page::from_address(self)
+ }
+
+ fn page_offset(&self) -> u32 {
+ self.0 as u32 & 0xfff
+ }
+}
+
+impl PageTableField {
+ fn is(&self, flags: PageTableFieldFlags) -> bool {
+ PageTableFieldFlags::from_bits_truncate(unsafe{*(self.0)}).contains(flags)
+ }
+
+ fn add_flag(&self, flags: PageTableFieldFlags) {
+ unsafe{*(self.0 as *mut u64) |= flags.bits};
+ }
+
+ fn remove_flag(&self, flags: PageTableFieldFlags) {
+ unsafe{*(self.0 as *mut u64) &= !flags.bits};
+ }
+
+ fn is_free(&self) -> bool {
+ //TODO
+ let f = unsafe{*self.0};
+ let free = f == 0;
+ free
+ }
+
+ fn pointed_frame(&self) -> Frame {
+ Frame {
+ number: ((unsafe{(*self.0)} & 0x000fffff_fffff000) >> 12) as usize,
+ }
+ }
+
+ fn set(&self, frame: Frame, flags: PageTableFieldFlags) {
+ let new = (((frame.number as u64) << 12) & 0x000fffff_fffff000) | flags.bits();
+ unsafe{*(self.0 as *mut u64) = new};
+ }
+}