63 lines
1.9 KiB
Rust
63 lines
1.9 KiB
Rust
use alloc::alloc::{GlobalAlloc, Layout};
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use bootloader::BootInfo;
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use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
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use core::ptr::null_mut;
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use x86_64::{
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structures::paging::{
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mapper::MapToError, FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB,
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},
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VirtAddr,
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};
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pub struct Dummy;
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unsafe impl GlobalAlloc for Dummy {
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unsafe fn alloc(&self, _layout: Layout) -> *mut u8 {
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null_mut()
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}
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unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
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panic!("dealloc should be never called")
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}
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}
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pub const HEAP_START: usize = 0x_4444_4444_0000;
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pub const HEAP_SIZE: usize = 100 * 1024; // 100 KiB
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pub fn init_heap(
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mapper: &mut impl Mapper<Size4KiB>,
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frame_allocator: &mut impl FrameAllocator<Size4KiB>,
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) -> Result<(), MapToError> {
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let page_range = {
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let heap_start = VirtAddr::new(HEAP_START as u64);
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let heap_end = heap_start + HEAP_SIZE - 1u64;
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let heap_start_page = Page::containing_address(heap_start);
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let heap_end_page = Page::containing_address(heap_end);
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Page::range_inclusive(heap_start_page, heap_end_page)
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};
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for page in page_range {
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let frame = frame_allocator
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.allocate_frame()
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.ok_or(MapToError::FrameAllocationFailed)?;
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let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
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unsafe { mapper.map_to(page, frame, flags, frame_allocator)?.flush() };
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}
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unsafe {
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super::ALLOCATOR.lock().init(HEAP_START, HEAP_SIZE);
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}
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Ok(())
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}
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pub fn init(boot_info: &'static BootInfo) {
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use crate::memory::{self, BootInfoFrameAllocator};
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let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
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let mut mapper = unsafe { memory::init(phys_mem_offset) };
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let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
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init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
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}
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