heap allocations

.cargo/config.toml

@@ -1,6 +1,6 @@
 [unstable]
 build-std-features = ["compiler-builtins-mem"]
-build-std = ["core", "compiler_builtins"]
+build-std = ["core", "compiler_builtins", "alloc"]
 
 [build]
 target = "x86_64-rust_os.json"

Cargo.lock

@@ -29,6 +29,30 @@ dependencies = [
  "spin",
 ]
 
+[[package]]
+name = "linked_list_allocator"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0b725207570aa16096962d0b20c79f8a543df2280bd3c903022b9b0b4d7ea68"
+dependencies = [
+ "spinning_top",
+]
+
+[[package]]
+name = "lock_api"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0382880606dff6d15c9476c416d18690b72742aa7b605bb6dd6ec9030fbf07eb"
+dependencies = [
+ "scopeguard",
+]
+
+[[package]]
+name = "pc-keyboard"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c6f2d937e3b8d63449b01401e2bae4041bc9dd1129c2e3e0d239407cf6635ac"
+
 [[package]]
 name = "pic8259"
 version = "0.10.1"
@@ -44,6 +68,8 @@ version = "0.1.0"
 dependencies = [
  "bootloader",
  "lazy_static",
+ "linked_list_allocator",
+ "pc-keyboard",
  "pic8259",
  "spin",
  "uart_16550",
@@ -51,12 +77,27 @@ dependencies = [
  "x86_64",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
 [[package]]
 name = "spin"
 version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
 
+[[package]]
+name = "spinning_top"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75adad84ee84b521fb2cca2d4fd0f1dab1d8d026bda3c5bea4ca63b5f9f9293c"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "uart_16550"
 version = "0.2.15"

Cargo.toml

@@ -4,13 +4,14 @@ version = "0.1.0"
 edition = "2018"
 
 [dependencies]
-bootloader = "0.9.8"
+bootloader = { version = "0.9.8", features = ["map_physical_memory"]}
 volatile = "0.2.6"
 spin = "0.5.2"
 x86_64 = "0.14.2"
 uart_16550 = "0.2.0"
 pic8259 = "0.10.1"
 pc-keyboard = "0.5.0"
+linked_list_allocator = "0.9.0"
 
 [dependencies.lazy_static]
 version = "1.0"

src/interrupts.rs

@@ -1,9 +1,17 @@
-use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
-use crate::println;
-use crate::print;
+use x86_64::structures::idt::{PageFaultErrorCode, InterruptDescriptorTable, InterruptStackFrame};
+use pic8259::ChainedPics;
 
 use lazy_static::lazy_static;
+
+use crate::println;
+use crate::print;
 use crate::gdt;
+use crate::hlt_loop;
+
+use spin;
+
+pub const PIC_1_OFFSET: u8 = 32;
+pub const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
 
 lazy_static! {
     static ref IDT: InterruptDescriptorTable = {
@@ -17,10 +25,24 @@ lazy_static! {
             .set_handler_fn(timer_interrupt_handler);
         idt[InterruptIndex::Keyboard.as_usize()]
             .set_handler_fn(keyboard_interrupt_handler);
+        idt.page_fault.set_handler_fn(page_fault_handler);
         idt
     };
 }
 
+extern "x86-interrupt" fn page_fault_handler(
+    stack_frame: 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();
+}
+    
 extern "x86-interrupt" fn double_fault_handler(
 	stack_frame: InterruptStackFrame, _error_code: u64) -> !
 {
@@ -37,6 +59,12 @@ extern "x86-interrupt" fn timer_interrupt_handler(
     }
 }
 
+extern "x86-interrupt" fn breakpoint_handler(
+    stack_frame: InterruptStackFrame)
+{
+    println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
+}
+
 extern "x86-interrupt" fn keyboard_interrupt_handler(
     _stack_frame: InterruptStackFrame)
 {
@@ -75,23 +103,6 @@ pub fn init_idt() {
     IDT.load();
 }
 
-#[test_case]
-fn test_breakpoint_exception() {
-    x86_64::instructions::interrupts::int3();
-}
-
-extern "x86-interrupt" fn breakpoint_handler(
-    stack_frame: InterruptStackFrame)
-{
-    println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
-}
-
-use pic8259::ChainedPics;
-use spin;
-
-pub const PIC_1_OFFSET: u8 = 32;
-pub const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
-
 pub static PICS: spin::Mutex<ChainedPics> =
     spin::Mutex::new(unsafe { ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });
 
@@ -111,3 +122,8 @@ impl InterruptIndex {
         usize::from(self.as_u8())
     }
 }
+
+#[test_case]
+fn test_breakpoint_exception() {
+    x86_64::instructions::interrupts::int3();
+}

src/lib.rs

@@ -1,6 +1,7 @@
 #![no_std]
 #![cfg_attr(test, no_main)]
 #![feature(custom_test_frameworks)]
+#![feature(alloc_error_handler)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 #![feature(abi_x86_interrupt)]
@@ -11,6 +12,16 @@ pub mod serial;
 pub mod vga_buffer;
 pub mod interrupts;
 pub mod gdt;
+pub mod memory;
+pub mod allocator;
+
+extern crate alloc;
+
+#[cfg(test)]
+use bootloader::{entry_point, BootInfo};
+
+#[cfg(test)]
+entry_point!(test_kernel_main);
 
 pub trait Testable {
     fn run(&self) -> ();
@@ -50,9 +61,8 @@ pub fn init() {
 }
 
 #[cfg(test)]
-#[no_mangle]
-pub extern "C" fn _start() -> ! {
-    init();      // new
+fn test_kernel_main(_boot_info: &'static BootInfo) -> ! {
+    init();
     test_main();
     hlt_loop();
 }
@@ -63,6 +73,11 @@ fn panic(info: &PanicInfo) -> ! {
     test_panic_handler(info)
 }
 
+#[alloc_error_handler]
+fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
+    panic!("allocation error: {:?}", layout)
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(u32)]
 pub enum QemuExitCode {

src/main.rs

@@ -4,16 +4,50 @@
 #![test_runner(rust_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 rust_os::println;
+use bootloader::{BootInfo, entry_point};
+use x86_64::VirtAddr;
+
+entry_point!(kernel_main);
+
+fn kernel_main(boot_info: &'static BootInfo) -> ! {
+    use rust_os::allocator;
+    use rust_os::memory::{self, BootInfoFrameAllocator};
 
-#[no_mangle]
-pub extern "C" fn _start() -> ! {
     println!("Hello World{}", "!");
-
     rust_os::init();
 
-    // as before
+    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");
+
+    // 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();
 
@@ -21,7 +55,6 @@ pub extern "C" fn _start() -> ! {
     rust_os::hlt_loop();
 }
 
-/// This function is called on panic.
 #[cfg(not(test))]
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {