michaelkuc6/blog_os
1
0
Fork 0
mirror of https://github.com/phil-opp/blog_os.git synced 2025-12-16 06:17:49 +00:00
Code Issues Projects Releases Wiki Activity

Create a memory::init function that initializes a MappedPageTable

Browse Source
This commit is contained in:
Philipp Oppermann
2019-03-13 14:08:43 +01:00
parent 9335386928
commit 98b5976656
1 changed files with 21 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
src/memory.rs
View File

@@ -1,4 +1,23 @@
use x86_64::{structures::paging::PageTable, PhysAddr, VirtAddr};
use x86_64::{
structures::paging::{MappedPageTable, MapperAllSizes, PageTable, PhysFrame},
PhysAddr, VirtAddr,
};
/// Initialize a new MappedPageTable.
///
/// This function is unsafe because the caller must guarantee that the
/// complete physical memory is mapped to virtual memory at the passed
/// `physical_memory_offset`. Also, this function must be only called once
/// to avoid aliasing `&mut` references (which is undefined behavior).
pub unsafe fn init(physical_memory_offset: u64) -> impl MapperAllSizes {
let level_4_table = active_level_4_table(physical_memory_offset);
let phys_to_virt = move |frame: PhysFrame| -> *mut PageTable {
let phys = frame.start_address().as_u64();
let virt = VirtAddr::new(phys + physical_memory_offset);
virt.as_mut_ptr()
};
MappedPageTable::new(level_4_table, phys_to_virt)
}
/// Returns a mutable reference to the active level 4 table.
///
@@ -6,7 +25,7 @@ use x86_64::{structures::paging::PageTable, PhysAddr, VirtAddr};
/// complete physical memory is mapped to virtual memory at the passed
/// `physical_memory_offset`. Also, this function must be only called once
/// to avoid aliasing `&mut` references (which is undefined behavior).
pub unsafe fn active_level_4_table(physical_memory_offset: u64) -> &'static mut PageTable {
unsafe fn active_level_4_table(physical_memory_offset: u64) -> &'static mut PageTable {
use x86_64::{registers::control::Cr3, VirtAddr};
let (level_4_table_frame, _) = Cr3::read();