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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,81 @@ | ||
| use x86_64::registers::control::Cr3; | ||
| use x86_64::structures::paging::{ | ||
| page::PageRangeInclusive, | ||
| OffsetPageTable, PageTable, PhysFrame, Size4KiB, | ||
| Page, PageTableFlags, Mapper, FrameAllocator, | ||
| }; | ||
| use x86_64::VirtAddr; | ||
|
|
||
| pub unsafe fn active_page_table() -> &'static mut PageTable { | ||
| let (frame, _) = Cr3::read(); | ||
| let phys_addr = frame.start_address(); | ||
| let virt_addr = super::phys_to_virt(phys_addr); | ||
| let page_table_ptr: *mut PageTable = virt_addr.as_mut_ptr(); | ||
| &mut *page_table_ptr // unsafe | ||
| } | ||
|
|
||
| pub unsafe fn create_page_table(frame: PhysFrame) -> &'static mut PageTable { | ||
| let phys_addr = frame.start_address(); | ||
| let virt_addr = super::phys_to_virt(phys_addr); | ||
| let page_table_ptr: *mut PageTable = virt_addr.as_mut_ptr(); | ||
| &mut *page_table_ptr // unsafe | ||
| } | ||
|
|
||
| pub fn alloc_pages( | ||
| mapper: &mut OffsetPageTable, addr: u64, size: usize | ||
| ) -> Result<(), ()> { | ||
| let size = size.saturating_sub(1) as u64; | ||
| let mut frame_allocator = super::frame_allocator(); | ||
|
|
||
| let pages = { | ||
| let start_page = Page::containing_address(VirtAddr::new(addr)); | ||
| let end_page = Page::containing_address(VirtAddr::new(addr + size)); | ||
| Page::range_inclusive(start_page, end_page) | ||
| }; | ||
|
|
||
| let flags = PageTableFlags::PRESENT | ||
| | PageTableFlags::WRITABLE | ||
| | PageTableFlags::USER_ACCESSIBLE; | ||
|
|
||
| for page in pages { | ||
| if let Some(frame) = frame_allocator.allocate_frame() { | ||
| let res = unsafe { | ||
| mapper.map_to(page, frame, flags, &mut frame_allocator) | ||
| }; | ||
| if let Ok(mapping) = res { | ||
| //debug!("Mapped {:?} to {:?}", page, frame); | ||
| mapping.flush(); | ||
| } else { | ||
| debug!("Could not map {:?} to {:?}", page, frame); | ||
| if let Ok(old_frame) = mapper.translate_page(page) { | ||
| debug!("Already mapped to {:?}", old_frame); | ||
| } | ||
| return Err(()); | ||
| } | ||
| } else { | ||
| debug!("Could not allocate frame for {:?}", page); | ||
| return Err(()); | ||
| } | ||
| } | ||
|
|
||
| Ok(()) | ||
| } | ||
|
|
||
| // TODO: Replace `free` by `dealloc` | ||
| pub fn free_pages(mapper: &mut OffsetPageTable, addr: u64, size: usize) { | ||
| let size = size.saturating_sub(1) as u64; | ||
|
|
||
| let pages: PageRangeInclusive<Size4KiB> = { | ||
| let start_page = Page::containing_address(VirtAddr::new(addr)); | ||
| let end_page = Page::containing_address(VirtAddr::new(addr + size)); | ||
| Page::range_inclusive(start_page, end_page) | ||
| }; | ||
|
|
||
| for page in pages { | ||
| if let Ok((_, mapping)) = mapper.unmap(page) { | ||
| mapping.flush(); | ||
| } else { | ||
| //debug!("Could not unmap {:?}", page); | ||
| } | ||
| } | ||
| } |