42 lines
1.4 KiB
Rust
42 lines
1.4 KiB
Rust
use alloc::alloc::{GlobalAlloc, Layout};
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use x86_64::{VirtAddr, structures::paging::{FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB, mapper::MapToError}};
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use core::ptr::null_mut;
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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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#[global_allocator]
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static ALLOCATOR: Dummy = Dummy;
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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(mapper: &mut impl Mapper<Size4KiB>, frame_allocator: &mut impl FrameAllocator<Size4KiB>) -> 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 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.allocate_frame().ok_or(MapToError::FrameAllocationFailed)?;
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let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
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unsafe {
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mapper.map_to(page, frame, flags, frame_allocator)?.flush()
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}
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}
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Ok(())
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}
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