90 lines
2.2 KiB
Rust
90 lines
2.2 KiB
Rust
use alloc::alloc::{GlobalAlloc, Layout};
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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 mod bump;
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pub mod fixed_size_block;
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pub mod linked_list;
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// use bump::BumpAllocator;
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use fixed_size_block::FixedSizeBlockAllocator;
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// use linked_list::LinkedListAllocator;
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#[global_allocator]
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static ALLOCATOR: Locked<FixedSizeBlockAllocator> =
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Locked::new(FixedSizeBlockAllocator::new());
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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 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 never be called")
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}
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}
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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<Size4KiB>> {
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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 head_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(head_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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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 struct Locked<A> {
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inner: spin::Mutex<A>,
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}
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impl<A> Locked<A> {
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pub const fn new(inner: A) -> Self {
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Locked {
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inner: spin::Mutex::new(inner),
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}
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}
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pub fn lock(&self) -> spin::MutexGuard<A> {
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self.inner.lock()
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}
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}
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fn align_up(addr: usize, align: usize) -> usize {
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let remainder = addr % align;
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if remainder == 0 {
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addr // addr already aligned
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} else {
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addr - remainder + align
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}
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}
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