JuliOS/src/memory/paging/mod.rs
Julien CLEMENT 273b004851 feat(paging): add frame allocator and mapping test
Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>
2021-12-07 19:00:34 +01:00

34 lines
1.3 KiB
Rust

use multiboot2::BootInformation;
use x86_64::structures::paging::{FrameAllocator, Size4KiB, PageTable, RecursivePageTable, Page, PageTableFlags as Flags, Mapper};
use crate::println;
use x86_64::VirtAddr;
pub const P4: *mut PageTable = 0o177777_777_777_777_777_0000 as *mut _;
pub fn kernel_remap<A>(_allocator: &mut A, _boot_info: &BootInformation)
where A: FrameAllocator<Size4KiB>
{
}
pub fn test_paging<A>(allocator: &mut A)
where A: FrameAllocator<Size4KiB>
{
let mut page_table = unsafe { RecursivePageTable::new(&mut *P4).expect("Could not create Page Table") };
let addr = 42 * 512 * 512 * 4096; // 42th P3 entry
let page = Page::containing_address(VirtAddr::new(addr));
let frame = allocator.allocate_frame().expect("no more frames");
println!("None = , map to {:?}", frame);
unsafe { page_table.map_to(page, frame, Flags::PRESENT, allocator).expect("Could not map").flush() };
println!("next free frame: {:?}", allocator.allocate_frame());
let page_ptr: *mut u8 = page.start_address().as_mut_ptr();
let frame_ptr: *mut u8 = frame.start_address().as_u64() as *mut u8;
unsafe {
println!("Page: {:#?}, Frame: {:#?}", *page_ptr, *frame_ptr);
*frame_ptr = 42;
println!("Page: {:#?}, Frame: {:#?}", *page_ptr, *frame_ptr);
}
}