allocation :D

Cargo.lock

@@ -41,6 +41,14 @@ 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 = "0.1.14"
@@ -101,6 +109,7 @@ version = "0.1.0"
 dependencies = [
  "bootloader 0.8.2 (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)",
@@ -117,6 +126,7 @@ dependencies = [
 "checksum cast 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "926013f2860c46252efceabb19f4a6b308197505082c609025aa6706c011d427"
 "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 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
 "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

@@ -7,13 +7,14 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bootloader = "0.8.0"
+bootloader = { version = "0.8.0", features = ["map_physical_memory"]}
 volatile = "0.2.6"
 spin = "0.5.2"
 x86_64 = "0.7.5"
 uart_16550 = "0.2.0"
 pic8259_simple = "0.1.1"
 pc-keyboard = "0.3.1"
+linked_list_allocator = "0.6.4"
 
 [dependencies.lazy_static]
 version = "1.0"

src/allocator.rs

@@ -0,0 +1,62 @@
+use alloc::alloc::{GlobalAlloc, Layout};
+use bootloader::BootInfo;
+use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
+use core::ptr::null_mut;
+use x86_64::{
+    structures::paging::{
+        mapper::MapToError, FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB,
+    },
+    VirtAddr,
+};
+
+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")
+    }
+}
+
+pub const HEAP_START: usize = 0x_4444_4444_0000;
+pub const HEAP_SIZE: usize = 100 * 1024; // 100 KiB
+
+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 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 {
+        super::ALLOCATOR.lock().init(HEAP_START, HEAP_SIZE);
+    }
+
+    Ok(())
+}
+
+pub fn init(boot_info: &'static BootInfo) {
+    use crate::memory::{self, BootInfoFrameAllocator};
+   
+    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) };
+
+    init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
+}

src/gdt.rs

@@ -1,7 +1,7 @@
-use x86_64::VirtAddr;
-use x86_64::structures::tss::TaskStateSegment;
 use lazy_static::lazy_static;
-use x86_64::structures::gdt::{GlobalDescriptorTable, Descriptor, SegmentSelector};
+use x86_64::structures::gdt::{Descriptor, GlobalDescriptorTable, SegmentSelector};
+use x86_64::structures::tss::TaskStateSegment;
+use x86_64::VirtAddr;
 
 pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
 
@@ -36,7 +36,13 @@ lazy_static! {
         let mut gdt = GlobalDescriptorTable::new();
         let code_selector = gdt.add_entry(Descriptor::kernel_code_segment());
         let tss_selector = gdt.add_entry(Descriptor::tss_segment(&TSS));
-        (gdt, Selectors { code_selector, tss_selector })
+        (
+            gdt,
+            Selectors {
+                code_selector,
+                tss_selector,
+            },
+        )
     };
 }
 

src/interrupts.rs

@@ -1,19 +1,19 @@
-use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
+use crate::{gdt, hlt_loop, print, println};
-use crate::{gdt, print, println};
 use lazy_static::lazy_static;
+use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
 
 lazy_static! {
     static ref IDT: InterruptDescriptorTable = {
         let mut idt = InterruptDescriptorTable::new();
         idt.breakpoint.set_handler_fn(breakpoint_handler);
+        idt.page_fault.set_handler_fn(page_fault_handler);
         unsafe {
-            idt.double_fault.set_handler_fn(double_fault_handler)
+            idt.double_fault
-                            .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
+                .set_handler_fn(double_fault_handler)
+                .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
         }
-        idt[InterruptIndex::Timer.as_usize()]
+        idt[InterruptIndex::Timer.as_usize()].set_handler_fn(timer_interrupt_handler);
-            .set_handler_fn(timer_interrupt_handler);
+        idt[InterruptIndex::Keyboard.as_usize()].set_handler_fn(keyboard_interrupt_handler);
-        idt[InterruptIndex::Keyboard.as_usize()]
-            .set_handler_fn(keyboard_interrupt_handler);
         idt
     };
 }
@@ -22,15 +22,14 @@ pub fn init_idt() {
     IDT.load();
 }
 
-extern "x86-interrupt" fn breakpoint_handler(
+extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
-    stack_frame: &mut InterruptStackFrame)
-{
     println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
 }
 
 extern "x86-interrupt" fn double_fault_handler(
-    stack_frame: &mut InterruptStackFrame, _error_code: u64)
+    stack_frame: &mut InterruptStackFrame,
-{
+    _error_code: u64,
+) {
     panic!("EXCEPTION: DOUBLE FAULT\n{:#?}", stack_frame);
 }
 
@@ -71,9 +70,7 @@ impl InterruptIndex {
     }
 }
 
-extern "x86-interrupt" fn timer_interrupt_handler(
+extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
-    _stack_frame: &mut InterruptStackFrame)
-{
     //print!(".");
 
     unsafe {
@@ -82,12 +79,10 @@ extern "x86-interrupt" fn timer_interrupt_handler(
     }
 }
 
-extern "x86-interrupt" fn keyboard_interrupt_handler(
+extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
-    _stack_frame: &mut InterruptStackFrame)
+    use pc_keyboard::{layouts, DecodedKey, Keyboard, ScancodeSet1};
-{
-    use x86_64::instructions::port::Port;
-    use pc_keyboard::{Keyboard, ScancodeSet1, DecodedKey, layouts};
     use spin::Mutex;
+    use x86_64::instructions::port::Port;
 
     lazy_static! {
         static ref KEYBOARD: Mutex<Keyboard<layouts::Us104Key, ScancodeSet1>> =
@@ -112,3 +107,18 @@ extern "x86-interrupt" fn keyboard_interrupt_handler(
             .notify_end_of_interrupt(InterruptIndex::Keyboard.as_u8());
     }
 }
+
+use x86_64::structures::idt::PageFaultErrorCode;
+
+extern "x86-interrupt" fn page_fault_handler(
+    stack_frame: &mut InterruptStackFrame,
+    error_code: PageFaultErrorCode,
+) {
+    use x86_64::registers::control::Cr2;
+
+    println!("EXCEPTION: PAGE FAULT");
+    println!("Accessed Address: {:?}", Cr2::read());
+    println!("Error Code: {:?}", error_code);
+    println!("{:#?}", stack_frame);
+    hlt_loop();
+}

src/lib.rs

@@ -1,22 +1,39 @@
 #![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"]
 
+extern crate alloc;
+
+pub mod allocator;
 pub mod gdt;
-pub mod serial;
 pub mod interrupts;
+pub mod memory;
+pub mod serial;
 pub mod vga_buffer;
 
-use core::panic::PanicInfo;
+use linked_list_allocator::LockedHeap;
 
-pub fn init() {
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();
+
+#[alloc_error_handler]
+fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
+    panic!("allocation error: {:?}", layout)
+}
+
+use core::panic::PanicInfo;
+use bootloader::BootInfo;
+
+pub fn init(boot_info: &'static BootInfo) {
     gdt::init();
     interrupts::init_idt();
     unsafe { interrupts::PICS.lock().initialize() };
     x86_64::instructions::interrupts::enable();
+    allocator::init(&boot_info);
 }
 
 pub fn hlt_loop() -> ! {
@@ -40,11 +57,16 @@ pub fn test_panic_handler(info: &PanicInfo) -> ! {
     hlt_loop();
 }
 
+#[cfg(test)]
+use bootloader::entry_point;
+
+#[cfg(test)]
+entry_point!(test_kernel_main);
+
 /// Entry point for `cargo xtest`
 #[cfg(test)]
-#[no_mangle]
+fn test_kernel_main(boot_info: &'static BootInfo) -> ! {
-pub extern "C" fn _start() -> ! {
+    init(boot_info);
-    init();
     test_main();
     hlt_loop();
 }

src/main.rs

@@ -4,14 +4,27 @@
 #![test_runner(xe_os::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
+extern crate alloc;
+
+use alloc::boxed::Box;
+use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
 use xe_os::println;
 
-#[no_mangle]
+entry_point!(kernel_main);
-pub extern "C" fn _start() -> ! {
+
-    xe_os::init();
+fn kernel_main(boot_info: &'static BootInfo) -> ! {
+    use x86_64::VirtAddr;
+    use xe_os::allocator;
+    use xe_os::memory::{self, BootInfoFrameAllocator};
+
+    xe_os::init(&boot_info);
     println!("Hello World{}", "!");
 
+    // allocate a number on the heap
+    let heap_value = Box::new(41);
+    println!("heap_value at {:p}", heap_value);
+
     #[cfg(test)]
     test_main();
 

src/memory.rs

@@ -0,0 +1,101 @@
+use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
+use x86_64::{
+    structures::paging::{
+        FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
+    },
+    PhysAddr, VirtAddr,
+};
+
+/// Initialize a new OffsetPageTable.
+///
+/// This function is unsafe because the caller must guarantee that the
+/// complete physical memory is mapped to virtual memory at the passed
+/// `physical_memory_offset`. Also, this function must be only called once
+/// to avoid aliasing `&mut` references (which is undefined behavior).
+pub unsafe fn init(physical_memory_offset: VirtAddr) -> OffsetPageTable<'static> {
+    let level_4_table = active_level_4_table(physical_memory_offset);
+    OffsetPageTable::new(level_4_table, physical_memory_offset)
+}
+
+/// Returns a mutable reference to the active level 4 table.
+///
+/// This function is unsafe because the caller must guarantee that the
+/// complete physical memory is mapped to virtual memory at the passed
+/// `physical_memory_offset`. Also, this function must be only called once
+/// to avoid aliasing `&mut` references (which is undefined behavior).
+unsafe fn active_level_4_table(physical_memory_offset: VirtAddr) -> &'static mut PageTable {
+    use x86_64::registers::control::Cr3;
+
+    let (level_4_table_frame, _) = Cr3::read();
+
+    let phys = level_4_table_frame.start_address();
+    let virt = physical_memory_offset + phys.as_u64();
+    let page_table_ptr: *mut PageTable = virt.as_mut_ptr();
+
+    &mut *page_table_ptr // unsafe
+}
+
+/// Creates an example mapping for the given page to frame `0xb8000`.
+pub fn create_example_mapping(
+    page: Page,
+    mapper: &mut OffsetPageTable,
+    frame_allocator: &mut impl FrameAllocator<Size4KiB>,
+) {
+    use x86_64::structures::paging::PageTableFlags as Flags;
+
+    let frame = PhysFrame::containing_address(PhysAddr::new(0xb8000));
+    let flags = Flags::PRESENT | Flags::WRITABLE;
+
+    let map_to_result = unsafe { mapper.map_to(page, frame, flags, frame_allocator) };
+    map_to_result.expect("map_to failed").flush();
+}
+
+/// A FrameAllocator that always returns `None`.
+pub struct EmptyFrameAllocator;
+
+unsafe impl FrameAllocator<Size4KiB> for EmptyFrameAllocator {
+    fn allocate_frame(&mut self) -> Option<PhysFrame> {
+        None
+    }
+}
+
+/// A FrameAllocator that returns usable frames from the bootloader's memory map.
+pub struct BootInfoFrameAllocator {
+    memory_map: &'static MemoryMap,
+    next: usize,
+}
+
+impl BootInfoFrameAllocator {
+    /// Create a FrameAllocator from the passed memory map.
+    ///
+    /// This function is unsafe because the caller must guarantee that the passed
+    /// memory map is valid. The main requirement is that all frames that are marked
+    /// as `USABLE` in it are really unused.
+    pub unsafe fn init(memory_map: &'static MemoryMap) -> Self {
+        BootInfoFrameAllocator {
+            memory_map,
+            next: 0,
+        }
+    }
+
+    /// Returns an iterator over the usable frames specified in the memory map.
+    fn usable_frames(&self) -> impl Iterator<Item = PhysFrame> {
+        // get usable regions from memory map
+        let regions = self.memory_map.iter();
+        let usable_regions = regions.filter(|r| r.region_type == MemoryRegionType::Usable);
+        // map each region to its address range
+        let addr_ranges = usable_regions.map(|r| r.range.start_addr()..r.range.end_addr());
+        // transform to an iterator of frame start addresses
+        let frame_addresses = addr_ranges.flat_map(|r| r.step_by(4096));
+        // create `PhysFrame` types from the start addresses
+        frame_addresses.map(|addr| PhysFrame::containing_address(PhysAddr::new(addr)))
+    }
+}
+
+unsafe impl FrameAllocator<Size4KiB> for BootInfoFrameAllocator {
+    fn allocate_frame(&mut self) -> Option<PhysFrame> {
+        let frame = self.usable_frames().nth(self.next);
+        self.next += 1;
+        frame
+    }
+}

src/serial.rs

@@ -1,6 +1,6 @@
-use uart_16550::SerialPort;
-use spin::Mutex;
 use lazy_static::lazy_static;
+use spin::Mutex;
+use uart_16550::SerialPort;
 
 lazy_static! {
     pub static ref SERIAL1: Mutex<SerialPort> = {
@@ -16,7 +16,10 @@ pub fn _print(args: ::core::fmt::Arguments) {
     use x86_64::instructions::interrupts;
 
     interrupts::without_interrupts(|| {
-        SERIAL1.lock().write_fmt(args).expect("Printing to serial failed");
+        SERIAL1
+            .lock()
+            .write_fmt(args)
+            .expect("Printing to serial failed");
     });
 }
 

tests/basic_boot.rs

@@ -5,10 +5,12 @@
 #![reexport_test_harness_main = "test_main"]
 
 use core::panic::PanicInfo;
+use bootloader::{entry_point, BootInfo};
 use xe_os::{println, serial_print, serial_println};
 
-#[no_mangle] // don't mangle the name of this function
+entry_point!(kmain);
-pub extern "C" fn _start() -> ! {
+
+fn kmain(_: &'static BootInfo) -> ! {
     test_main();
 
     loop {}

tests/heap_allocation.rs

@@ -0,0 +1,53 @@
+#![no_std]
+#![no_main]
+#![feature(custom_test_frameworks)]
+#![test_runner(xe_os::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+
+extern crate alloc;
+
+use bootloader::{entry_point, BootInfo};
+use core::panic::PanicInfo;
+
+entry_point!(main);
+
+fn main(boot_info: &'static BootInfo) -> ! {
+    use xe_os::allocator;
+    use xe_os::memory::{self, BootInfoFrameAllocator};
+    use x86_64::VirtAddr;
+
+    xe_os::init(boot_info);
+
+    test_main();
+    loop {}
+}
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    xe_os::test_panic_handler(info)
+}
+
+use xe_os::{serial_print, serial_println};
+use alloc::boxed::Box;
+
+#[test_case]
+fn simple_allocation() {
+    serial_print!("simple_allocation... ");
+    let heap_value = Box::new(41);
+    assert_eq!(*heap_value, 41);
+    serial_println!("[ok]");
+}
+
+use alloc::vec::Vec;
+
+#[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]");
+}

tests/should_panic.rs

@@ -9,7 +9,7 @@ pub extern "C" fn _start() -> ! {
     should_fail();
     serial_println!("[test did not panic]");
     exit_qemu(QemuExitCode::Failed);
-    loop{}
+    loop {}
 }
 
 fn should_fail() {

tests/stack_overflow.rs

@@ -43,8 +43,8 @@ lazy_static! {
     };
 }
 
-use xe_os::{exit_qemu, QemuExitCode, serial_println};
 use x86_64::structures::idt::InterruptStackFrame;
+use xe_os::{exit_qemu, serial_println, QemuExitCode};
 
 extern "x86-interrupt" fn test_double_fault_handler(
     _stack_frame: &mut InterruptStackFrame,