post-10

Cargo.lock

@@ -24,6 +24,7 @@ version = "0.1.0"
 dependencies = [
  "bootloader 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "linked_list_allocator 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "pc-keyboard 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "pic8259_simple 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -60,6 +61,14 @@ dependencies = [
  "spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "linked_list_allocator"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "nodrop"
 version = "0.1.13"
@@ -167,6 +176,7 @@ dependencies = [
 "checksum cc 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)" = "4fc9a35e1f4290eb9e5fc54ba6cf40671ed2a2514c3eeb2b2a908dda2ea5a1be"
 "checksum cpuio 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "22b8e308ccfc5acf3b82f79c0eac444cf6114cb2ac67a230ca6c177210068daa"
 "checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+"checksum linked_list_allocator 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "47314ec1d29aa869ee7cb5a5be57be9b1055c56567d59c3fb6689926743e0bea"
 "checksum nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9667ddcc6cc8a43afc9b7917599d7216aa09c463919ea32c59ed6cac8bc945"
 "checksum pc-keyboard 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fff50ab09ba31bcebc0669f4e64c0952fae1acdca9e6e0587e68e4e8443808ac"
 "checksum pic8259_simple 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dc64b2fd10828da8521b6cdabe0679385d7d2a3a6d4c336b819d1fa31ba35c72"

Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 
 [dependencies]
 bootloader = { version = "0.8.1", features = ["map_physical_memory"]}
+linked_list_allocator = "0.6.4"
 pc-keyboard = "0.3.1"
 pic8259_simple = "0.1.1"
 spin = "0.5.2"

src/allocator.rs

@@ -0,0 +1,56 @@
+use alloc::alloc::{GlobalAlloc, Layout};
+use core::ptr::null_mut;
+use x86_64:: {
+    structures::paging:: {
+        FrameAllocator,
+        mapper::MapToError,
+        Mapper,
+        Page,
+        PageTableFlags,
+        Size4KiB,
+    },
+    VirtAddr,
+};
+
+pub const HEAP_START: usize = 0x_4444_4444_0000;
+pub const HEAP_SIZE: usize = 100 * 1024; // 100 KiB
+
+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 never be called")
+    }
+}
+
+pub fn init_heap(
+    mapper: &mut impl Mapper<Size4KiB>,
+    frame_allocator: &mut impl FrameAllocator<Size4KiB>,
+) -> Result<(), MapToError> {
+    let page_range = {
+        let heap_start = VirtAddr::new(HEAP_START as u64);
+        let head_end = heap_start + HEAP_SIZE - 1u64;
+        let heap_start_page = Page::containing_address(heap_start);
+        let heap_end_page = Page::containing_address(head_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 {
+        super::ALLOCATOR.lock().init(HEAP_START, HEAP_SIZE);
+    }
+
+    Ok(())
+}

src/lib.rs

@@ -1,11 +1,15 @@
 #![no_std]
 #![cfg_attr(test, no_main)]
+#![feature(alloc_error_handler)]
 #![feature(custom_test_frameworks)]
 #![feature(abi_x86_interrupt)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
+extern crate alloc;
+
 use core::panic::PanicInfo;
+use linked_list_allocator::LockedHeap;
 
 #[cfg(test)]
 use bootloader::{entry_point, BootInfo};
@@ -13,6 +17,15 @@ use bootloader::{entry_point, BootInfo};
 #[cfg(test)]
 entry_point!(test_kernel_main);
 
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();
+
+#[alloc_error_handler]
+fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
+    panic!("allocation error: {:?}", layout)
+}
+
+pub mod allocator;
 pub mod gdt;
 pub mod interrupts;
 pub mod macros;

src/main.rs

@@ -4,6 +4,14 @@
 #![test_runner(blog_os::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
+extern crate alloc;
+
+use alloc::{
+    boxed::Box,
+    vec,
+    vec::Vec,
+    rc::Rc,
+};
 use core::panic::PanicInfo;
 
 use blog_os::println;
@@ -26,24 +34,38 @@ fn panic(info: &PanicInfo) -> ! {
 entry_point!(kernel_main);
 
 fn kernel_main(boot_info: &'static BootInfo) -> ! {
-    use blog_os::memory;
-    use x86_64::{structures::paging::Page, VirtAddr};
+    use blog_os::allocator;
+    use blog_os::memory::{self, BootInfoFrameAllocator};
+    use x86_64::VirtAddr;
 
     println!("Hello World{}", "!");
     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 { memory::BootInfoFrameAllocator::init(&boot_info.memory_map) };
+    let mut mapper = unsafe { memory::init(VirtAddr::new(boot_info.physical_memory_offset)) };
+    let mut frame_allocator = unsafe {
+        BootInfoFrameAllocator::init(&boot_info.memory_map)
+    };
 
-    let page = Page::containing_address(VirtAddr::new(0xdeadbeef000));
-    memory::create_example_mapping(page, &mut mapper, &mut frame_allocator);
+    allocator::init_heap(&mut mapper, &mut frame_allocator)
+        .expect("heap initialization failed");
 
-    let page_ptr: *mut u64 = page.start_address().as_mut_ptr();
-    unsafe {
-        page_ptr.offset(400).write_volatile(0x_f021_f077_f065_f04e);
+    // allocate a number on the heap
+    let heap_value = Box::new(41);
+    println!("heap_value at {:p}", heap_value);
+
+    // create a dynamically sized vector
+    let mut vec = Vec::new();
+    for i in 0..500 {
+        vec.push(i);
     }
+    println!("vec at {:p}", vec.as_slice());
+
+    // create a reference counted vector -> will be freed when count reaches 0
+    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 +1,69 @@
+#![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;
+use alloc::vec::Vec;
+use blog_os::{serial_print, serial_println};
+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() {
+    serial_print!("simple allocation... ");
+    let heap_value = Box::new(41);
+    assert_eq!(*heap_value, 41);
+    serial_println!("[ok]");
+}
+
+#[test_case]
+fn large_vec() {
+    serial_print!("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);
+    serial_println!("[ok]");
+}
+
+#[test_case]
+fn many_boxes() {
+    serial_print!("many_boxes... ");
+    for i in 0..10_000 {
+        let x = Box::new(i);
+        assert_eq!(*x, i);
+    }
+    serial_println!("[ok]");
+}