Heap Allocation

src/allocator.rs

@@ -0,0 +1,54 @@
+use alloc::alloc::{GlobalAlloc, Layout};
+use core::ptr::null_mut;
+use linked_list_allocator::LockedHeap;
+use x86_64::{
+    structures::paging::{
+        mapper::MapToError, FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB,
+    },
+    VirtAddr,
+};
+
+pub const HEAP_START: usize = 0x_4444_4444_0000;
+pub const HEAP_SIZE: usize = 100 * 1024;
+
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();
+
+pub fn init_heap(
+    mapper: &mut impl Mapper<Size4KiB>,
+    frame_allocator: &mut impl FrameAllocator<Size4KiB>,
+) -> Result<(), MapToError<Size4KiB>> {
+    let page_range = {
+        let heap_start = VirtAddr::new(HEAP_START as u64);
+        let heap_end = heap_start + HEAP_SIZE - 1u64;
+        let heap_start_page = Page::containing_address(heap_start);
+        let heap_end_page = Page::containing_address(heap_end);
+        Page::range_inclusive(heap_start_page, heap_end_page)
+    };
+
+    for page in page_range {
+        let frame = frame_allocator
+            .allocate_frame()
+            .ok_or(MapToError::FrameAllocationFailed)?;
+        let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
+        unsafe { mapper.map_to(page, frame, flags, frame_allocator)?.flush() };
+    }
+
+    unsafe {
+        ALLOCATOR.lock().init(HEAP_START, HEAP_SIZE);
+    }
+
+    Ok(())
+}
+
+pub struct Dummy;
+
+unsafe impl GlobalAlloc for Dummy {
+    unsafe fn alloc(&self, _layout: Layout) -> *mut u8 {
+        null_mut()
+    }
+
+    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
+        panic!("dealloc should be never called")
+    }
+}

src/lib.rs

@@ -4,6 +4,9 @@
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 #![feature(abi_x86_interrupt)]
+#![feature(alloc_error_handler)]
+
+extern crate alloc;
 
 use core::panic::PanicInfo;
 pub mod gdt;
@@ -11,6 +14,7 @@ pub mod interrupts;
 pub mod memory;
 pub mod serial;
 pub mod vga_buffer;
+pub mod allocator;
 
 pub trait Testable {
     fn run(&self) -> ();
@@ -91,6 +95,11 @@ pub fn hlt_loop() -> ! {
     }
 }
 
+#[alloc_error_handler]
+fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
+    panic!("allocation error: {:?}", layout);
+}
+
 pub fn init() {
     gdt::init();
     interrupts::init_idt();

src/main.rs

@@ -4,14 +4,18 @@
 #![test_runner(anos::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
+extern crate alloc;
+
 use anos::println;
 use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
+use alloc::{boxed::Box, rc::Rc, vec, vec::Vec};
 
 entry_point!(kernel_main);
 
 fn kernel_main(boot_info: &'static BootInfo) -> ! {
     use anos::memory::{self, BootInfoFrameAllocator};
+    use anos::allocator;
     use x86_64::{structures::paging::Page, VirtAddr};
 
     println!("Hello World{}", "!");
@@ -27,6 +31,29 @@ fn kernel_main(boot_info: &'static BootInfo) -> ! {
     let page_ptr: *mut u64 = page.start_address().as_mut_ptr();
     unsafe { page_ptr.offset(400).write_volatile(0x_f021_f077_f065_f04e) };
 
+    allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
+
+    let heap_value = Box::new(41);
+    println!("heap_value at {:p}", heap_value);
+
+    let mut vec = Vec::new();
+    for i in 0..500 {
+        vec.push(i);
+    }
+    println!("vec at {:p}", vec.as_slice());
+
+    let reference_counted = Rc::new(vec![1, 2, 3]);
+    let cloned_reference = reference_counted.clone();
+    println!(
+        "current reference count is {}",
+        Rc::strong_count(&cloned_reference)
+    );
+    core::mem::drop(reference_counted);
+    println!(
+        "reference count is {} now",
+        Rc::strong_count(&cloned_reference)
+    );
+
     // 触发一个中断
     x86_64::instructions::interrupts::int3();
     println!("It didn't crash!");