add heap allocator

.cargo/config.toml

@@ -1,5 +1,5 @@
 [unstable]
-build-std = ["core", "compiler_builtins"]
+build-std = ["core", "compiler_builtins", "alloc"]
 build-std-features = ["compiler-builtins-mem"]
 
 [build]

Cargo.toml

@@ -14,7 +14,8 @@ version = "0.4.1"
 panic = "abort" # disable stack unwinding on panic
 
 [dependencies]
-bootloader = {version = "0.9.8", features = ["map_physical_memory"]}# for BIOS bootloader.  
+bootloader = {version = "0.9.8", features = ["map_physical_memory"]}# for BIOS bootloader.   
+linked_list_allocator = "0.8.0" 
 pc-keyboard = "0.5.0" # interprets PS/2 keyboard scancode sets 1 and 2
 pic8259_simple = "0.2.0" # keyboard interrupts
 spin = "0.5.2" 

src/allocator.rs

@@ -0,0 +1,53 @@
+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 = 0x4444_4444_0000;
+pub const HEAP_SIZE: usize = 100 * 1024;
+
+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(())
+}
+
+/// Implements [GlobalAlloc]
+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) {}
+}
+
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();

src/lib.rs

@@ -1,6 +1,7 @@
 #![no_std]
 #![cfg_attr(test, no_main)]
 #![feature(abi_x86_interrupt)]
+#![feature(alloc_error_handler)]
 #![feature(custom_test_frameworks)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
@@ -10,12 +11,20 @@ use core::panic::PanicInfo;
 #[cfg(test)]
 use bootloader::{entry_point, BootInfo};
 
+extern crate alloc;
+
+pub mod allocator;
 pub mod gdt;
 pub mod interrupts;
 pub mod memory;
 pub mod serial;
 pub mod vga_buffer;
 
+#[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

@@ -4,7 +4,10 @@
 #![test_runner(blog_os::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
-use blog_os::{memory::BootInfoFrameAllocator, println};
+extern crate alloc;
+
+use alloc::{boxed::Box, rc::Rc, vec, vec::Vec};
+use blog_os::{allocator, memory::BootInfoFrameAllocator, println};
 use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
 
@@ -21,8 +24,31 @@ pub fn kernel_main(boot_info: &'static BootInfo) -> ! {
     // initialize page table and frame allocator
     // TODO: move to blog_os::init?
     let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
-    let mut _mapper = unsafe { memory::init(phys_mem_offset) };
-    let mut _frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
+    let mut mapper = unsafe { memory::init(phys_mem_offset) };
+    let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
+
+    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)
+    );
 
     #[cfg(test)]
     test_main();

tests/heap_allocation.rs

@@ -0,0 +1,54 @@
+// in tests/heap_allocation.rs
+
+#![no_std]
+#![no_main]
+#![feature(custom_test_frameworks)]
+#![test_runner(blog_os::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+
+extern crate alloc;
+
+use alloc::{boxed::Box, vec::Vec};
+
+use bootloader::{entry_point, BootInfo};
+use core::panic::PanicInfo;
+
+entry_point!(main);
+
+fn main(boot_info: &'static BootInfo) -> ! {
+    use blog_os::allocator;
+    use blog_os::memory::{self, BootInfoFrameAllocator};
+    use x86_64::VirtAddr;
+
+    blog_os::init();
+    let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
+    let mut mapper = unsafe { memory::init(phys_mem_offset) };
+    let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
+    allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
+
+    test_main();
+    loop {}
+}
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    blog_os::test_panic_handler(info)
+}
+
+#[test_case]
+fn simple_allocation() {
+    let heap_value_1 = Box::new(41);
+    let heap_value_2 = Box::new(13);
+    assert_eq!(*heap_value_1, 41);
+    assert_eq!(*heap_value_2, 13);
+}
+
+#[test_case]
+fn large_vec() {
+    let n = 1000;
+    let mut vec = Vec::new();
+    for i in 0..n {
+        vec.push(i);
+    }
+    assert_eq!(vec.iter().sum::<u64>(), (n - 1) * n / 2);
+}