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feat(paging): map kernel using elf section flags

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Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>
This commit is contained in:
Julien CLEMENT 2021-12-08 16:20:38 +01:00
parent 5e994b9dff
commit 5ff8596233
2 changed files with 37 additions and 8 deletions
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17
src/lib.rs
View File

@ -12,6 +12,8 @@ extern crate multiboot2;
use core::panic::PanicInfo;
use vga::{Color, ColorCode};
use memory::paging::{Size4KiB, FrameAllocator};
use multiboot2::BootInformation;
#[panic_handler]
fn panic_handler(info: &PanicInfo) -> ! {
@ -26,14 +28,24 @@ pub fn hlt_loop() -> ! {
}
}
pub fn init() {
pub fn init<A>(frame_allocator: &mut A, boot_info: &BootInformation)
where A: FrameAllocator<Size4KiB>
{
vga::change_color(ColorCode::new(Color::LightCyan, Color::Black));
println!("Starting init");
enable_nxe_bit();
memory::kernel_remap(frame_allocator, boot_info);
gdt::init_gdt();
interrupts::init_idt();
vga::change_color(ColorCode::new(Color::LightGreen, Color::Black));
}
fn enable_nxe_bit() {
println!("Enabling nxe bit");
use x86_64::registers::control::{Efer, EferFlags};
unsafe { Efer::update(|efer| *efer |= EferFlags::NO_EXECUTE_ENABLE) }
}
fn get_frame_allocator(multiboot_info_addr: usize) -> memory::AreaFrameAllocator {
let boot_info = unsafe { multiboot2::load(multiboot_info_addr) };
let memory_map_tag = boot_info.memory_map_tag().expect("Memory map tag required");
@ -62,9 +74,8 @@ pub extern "C" fn julios_main(multiboot_info_addr: usize) -> ! {
let mut frame_allocator = get_frame_allocator(multiboot_info_addr);
memory::kernel_remap(&mut frame_allocator, boot_info);
init();
init(&mut frame_allocator, &boot_info);
println!("***JuliOS V0.1.0***");
serial_println!("Hello serial");
memory::paging::test_paging(&mut frame_allocator);

28
src/memory/paging/mod.rs
View File

@ -1,4 +1,4 @@
use multiboot2::BootInformation;
use multiboot2::{BootInformation, ElfSection};
pub use x86_64::structures::paging::{FrameAllocator, Size4KiB, PageTable, RecursivePageTable, Page, PageTableFlags as Flags, Mapper, PhysFrame as Frame};
use crate::println;
use x86_64::{VirtAddr, PhysAddr};
@ -10,9 +10,29 @@ mod temporary_page;
pub const P4: *mut PageTable = 0o177777_777_777_777_777_0000 as *mut _;
fn get_flags_from_elf_section(section: &ElfSection) -> Flags {
use multiboot2::{ELF_SECTION_ALLOCATED, ELF_SECTION_WRITABLE,
ELF_SECTION_EXECUTABLE};
let mut flags = Flags::empty();
if section.flags().contains(ELF_SECTION_ALLOCATED) {
flags = flags | Flags::PRESENT;
}
if section.flags().contains(ELF_SECTION_WRITABLE) {
flags = flags | Flags::WRITABLE;
}
if !section.flags().contains(ELF_SECTION_EXECUTABLE) {
flags = flags | Flags::NO_EXECUTE;
}
flags
}
pub fn kernel_remap<A>(allocator: &mut A, boot_info: &BootInformation)
where A: FrameAllocator<Size4KiB>
{
println!("Remapping kernel");
let mut temporary_page = TemporaryPage::new(Page::containing_address(VirtAddr::new(0xcafebabe)), allocator);
let mut active_table = get_active_page_table();
let mut new_table = {
@ -33,7 +53,7 @@ pub fn kernel_remap<A>(allocator: &mut A, boot_info: &BootInformation)
"sections need to be page aligned");
let flags = Flags::WRITABLE | Flags::PRESENT;
let flags = get_flags_from_elf_section(section);
let start_frame = Frame::<Size4KiB>::containing_address(PhysAddr::new(section.start_address() as u64));
let end_frame = Frame::containing_address(PhysAddr::new(section.end_address() as u64 - 1));
@ -129,7 +149,5 @@ pub fn test_paging<A>(allocator: &mut A)
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);
}
println!("Page: {:#?}, Frame: {:#?}", page_ptr, frame_ptr);
}