Some code?

.cargo/config

@@ -1,2 +1,10 @@
+[unstable]
+build-std = ["core", "compiler_builtins"]
+build-std-features = ["compiler-builtins-mem"]
+
 [build]
-target = "os.json"
+target = "x86_64_target.json"
+
+# Facilitates running tests with qemu
+[target.'cfg(target_os = "none")']
+runner = "bootimage runner"

Cargo.lock

@@ -0,0 +1,98 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "bit_field"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcb6dd1c2376d2e096796e234a70e17e94cc2d5d54ff8ce42b28cef1d0d359a4"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "bootloader"
+version = "0.9.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a62c8f6168cd106687ee36a2b71a46c4144d73399f72814104d33094b8092fd2"
+
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+dependencies = [
+ "spin 0.5.2",
+]
+
+[[package]]
+name = "lock_api"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88943dd7ef4a2e5a4bfa2753aaab3013e34ce2533d1996fb18ef591e315e2b3b"
+dependencies = [
+ "scopeguard",
+]
+
+[[package]]
+name = "rustos"
+version = "0.1.0"
+dependencies = [
+ "bootloader",
+ "lazy_static",
+ "spin 0.9.2",
+ "uart_16550",
+ "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 = "spin"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "511254be0c5bcf062b019a6c89c01a664aa359ded62f78aa72c6fc137c0590e5"
+dependencies = [
+ "lock_api",
+]
+
+[[package]]
+name = "uart_16550"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af81448a9a53c7b0f66198381f80912fd18f2c8965f9da4319e6f92e740bca5b"
+dependencies = [
+ "bitflags",
+ "x86_64",
+]
+
+[[package]]
+name = "volatile"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e4c2dbd44eb8b53973357e6e207e370f0c1059990df850aca1eca8947cf464f0"
+
+[[package]]
+name = "x86_64"
+version = "0.14.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "958ab3202b01bc43ba2eb832102c4a487ed93151667a2289062e5f2b00058be2"
+dependencies = [
+ "bit_field",
+ "bitflags",
+ "volatile",
+]

Cargo.toml

@@ -2,17 +2,22 @@
 name = "rustos"
 version = "0.1.0"
 authors = ["greg <greg.shuflin@protonmail.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
-bootloader = { version = "0.6.4", features = ["map_physical_memory"] }
-volatile = "0.2.6"
-spin = "0.5.0"
-x86_64 = "0.7.2"
-pic8259_simple = "0.1.1"
-pc-keyboard = "0.5.0"
+#bootloader = "0.10.12"
+bootloader = "0.9.8"
+spin = "0.9.2"
+x86_64 = "0.14.8"
+uart_16550 = "0.2.16"
 
 [dependencies.lazy_static]
-version = "1.3.0"
+version = "1.4.0"
 features = ["spin_no_std"]
 
+
+[package.metadata.bootimage]
+test-args = ["-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio",
+            "-display", "none"]
+test-success-exit-code = 33 # (0x10 << 1) | 1
+test-timeout = 10 # timeout in seconds

justfile

@@ -0,0 +1,7 @@
+default:
+    just --list
+
+run_os:
+    cargo bootimage
+    qemu-system-x86_64 -drive format=raw,file=target/x86_64_target/debug/bootimage-rustos.bin
+

run.sh

@@ -1,5 +0,0 @@
-#!/bin/sh
-
-cargo bootimage
-qemu-system-x86_64 -drive format=raw,file=target/os/debug/bootimage-rustos.bin
-

src/gdt.rs

@@ -1,47 +1,33 @@
-use x86_64::VirtAddr;
-use x86_64::structures::tss::TaskStateSegment;
-use x86_64::structures::gdt::{GlobalDescriptorTable, Descriptor, SegmentSelector};
 use lazy_static::lazy_static;
+use x86_64::structures::gdt::{Descriptor, GlobalDescriptorTable, SegmentSelector};
+use x86_64::structures::tss::TaskStateSegment;
+use x86_64::VirtAddr;
 
-//double fault interrupt stack table
 pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
 
 lazy_static! {
-  static ref TSS: TaskStateSegment = {
-    let mut tss = TaskStateSegment::new();
-    tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
-      const STACK_SIZE: usize = 4096; //4k stack
-
-      //this static mut is temporarily the stack until proper allocation can be implemented
-      static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
-      let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
-      let stack_end = stack_start + STACK_SIZE;
-      stack_end
+    static ref TSS: TaskStateSegment = {
+        let mut tss = TaskStateSegment::new();
+        tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
+            const STACK_SIZE: usize = 4096 * 5;
+            static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
+            let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
+            let stack_end = stack_start + STACK_SIZE;
+            stack_end
+        };
+        tss
     };
-    tss
-  };
-}
-
-struct Selectors {
-  code_selector: SegmentSelector,
-  data_selector: SegmentSelector,
 }
 
 lazy_static! {
-  static ref GDT: (GlobalDescriptorTable, Selectors) = {
-    let mut gdt = GlobalDescriptorTable::new();
-    let code_selector = gdt.add_entry(Descriptor::kernel_code_segment());
-    let data_selector = gdt.add_entry(Descriptor::tss_segment(&TSS));
-    (gdt, Selectors { code_selector, data_selector })
-  };
+    static ref GDT: GlobalDescriptorTable = {
+        let mut gdt = GlobalDescriptorTable::new();
+        gdt.add_entry(Descriptor::kernel_code_segment());
+        gdt.add_entry(Descriptor::tss_segment(&TSS));
+        gdt
+    };
 }
 
 pub fn init() {
-  use x86_64::instructions::segmentation::set_cs;
-  use x86_64::instructions::tables::load_tss;
-  GDT.0.load();
-  unsafe {
-    set_cs(GDT.1.code_selector);
-    load_tss(GDT.1.data_selector);
-  }
+    GDT.load();
 }

src/interrupts.rs

@@ -1,98 +1,26 @@
 use lazy_static::lazy_static;
-use x86_64::structures::idt::{InterruptStackFrame, InterruptDescriptorTable};
-use crate::println;
-use pic8259_simple::ChainedPics;
-use spin;
-use crate::gdt;
-
-#[derive(Copy, Clone, Debug)]
-#[repr(u8)]
-pub enum InterruptIndex {
-  Timer = PIC_1_OFFSET,
-  Keyboard,
-}
-
-impl InterruptIndex {
-  fn as_u8(self) -> u8 {
-    self as u8
-  }
-  fn as_usize(self) -> usize {
-    usize::from(self as u8)
-  }
-}
-
-
-const PIC_1_OFFSET: u8 = 32;
-const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
-static PICS: spin::Mutex<ChainedPics> =
-    spin::Mutex::new(unsafe { ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });
+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);
-    unsafe {
-    idt.double_fault.set_handler_fn(double_fault_handler)
-      .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
-    }
-    idt[InterruptIndex::Timer.as_usize()]
-      .set_handler_fn(timer_interrupt_handler);
-    idt[InterruptIndex::Keyboard.as_usize()]
-      .set_handler_fn(keyboard_interrupt_handler);
-    idt
-  };
+    static ref IDT: InterruptDescriptorTable = {
+        let mut idt = InterruptDescriptorTable::new();
+        idt.breakpoint.set_handler_fn(breakpoint_handler);
+        idt.double_fault.set_handler_fn(double_fault_handler);
+        idt
+    };
 }
-
 pub fn init_idt() {
-  IDT.load();
+    IDT.load();
 }
 
-pub fn initalize_pics() {
-  unsafe {
-    PICS.lock().initialize();
-  }
-  x86_64::instructions::interrupts::enable();
+extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
+    println!("EXCEPTION: Breakpoint\n{:#?}", stack_frame);
 }
 
-extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
-
-  println!("EXCEPTION - BREAKPOINT\n{:#?}", stack_frame);
-}
-
-extern "x86-interrupt" fn double_fault_handler(stack_frame: &mut InterruptStackFrame, code: u64) {
-  panic!("EXCEPTION - DOUBLE FAULT (code {})\n{:#?}", code, stack_frame);
-}
-
-extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
-  print!(".");
-  unsafe {
-    PICS.lock().notify_end_of_interrupt(InterruptIndex::Timer.as_u8())
-  }
-}
-
-extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
-  use x86_64::instructions::port::Port;
-  use pc_keyboard::{Keyboard, ScancodeSet1, DecodedKey, HandleControl, layouts};
-  use spin::Mutex;
-
-  lazy_static! {
-    static ref KEYBOARD: Mutex<Keyboard<layouts::Us104Key, ScancodeSet1>> =
-      Mutex::new(Keyboard::new(layouts::Us104Key, ScancodeSet1, HandleControl::Ignore));
-  }
-
-  let mut keyboard = KEYBOARD.lock();
-  let mut port = Port::new(0x60);
-  let scancode: u8 = unsafe { port.read() };
-
-  if let Ok(Some(key_event)) = keyboard.add_byte(scancode) {
-    if let Some(key) = keyboard.process_keyevent(key_event) {
-      match key {
-	DecodedKey::Unicode(character) => print!("{}", character),
-	DecodedKey::RawKey(key) => print!("{:?}", key),
-      }
-    }
-  }
-  unsafe {
-    PICS.lock().notify_end_of_interrupt(InterruptIndex::Keyboard.as_u8())
-  }
+// The error code of the double-fault handler is always 0
+extern "x86-interrupt" fn double_fault_handler(
+    stack_frame: InterruptStackFrame,
+    _error_code: u64,
+) -> ! {
+    panic!("Exception: Double fault\n{:#?}", stack_frame)
 }

src/main.rs

@@ -1,41 +1,51 @@
-#![feature(abi_x86_interrupt, asm)]
+#![feature(abi_x86_interrupt)]
 #![no_std]
 #![no_main]
+#![feature(custom_test_frameworks)]
+#![test_runner(crate::test_utils::test_runner)]
+#![reexport_test_harness_main = "test_main"]
 
 #[macro_use]
 mod vga_buffer;
-mod interrupts;
+#[macro_use]
+mod serial;
 mod gdt;
+mod interrupts;
+mod test_utils;
 
-use core::panic::PanicInfo;
-
+#[cfg(not(test))]
 #[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-  println!("{}", info);
-  halt_loop();
-}
-
-pub fn init() {
-  interrupts::initalize_pics();
-  gdt::init();
-  interrupts::init_idt();
+fn panic(info: &core::panic::PanicInfo) -> ! {
+    println!("{info}");
+    loop {}
 }
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
-  init();
+    #[cfg(test)]
+    test_main();
 
+    println!("Gamarjoba, munde!");
+    init();
 
+    // Deliberate breakpoint exception
+    x86_64::instructions::interrupts::int3();
 
-  for i in 1..10 {
-    println!("Gamarjoba, munde: {}", i);
-  }
-  halt_loop();
+    println!("We're here now");
+    loop {}
 }
 
-pub fn halt_loop() -> ! {
-  loop {
-    x86_64::instructions::hlt();
-  }
+#[test_case]
+fn basic_test() {
+    assert_eq!(5, 5);
 }
 
+#[test_case]
+fn basic_test2() {
+    assert_eq!(4, 4);
+}
+
+pub fn init() {
+    gdt::init();
+    interrupts::init_idt();
+}

src/serial.rs

@@ -0,0 +1,32 @@
+use lazy_static::lazy_static;
+use spin::Mutex;
+use uart_16550::SerialPort;
+
+lazy_static! {
+    pub static ref SERIAL1: Mutex<SerialPort> = {
+        let mut serial_port = unsafe { SerialPort::new(0x3f8) }; // 0x3f8 is standard address of 1st serial port
+        serial_port.init();
+        Mutex::new(serial_port)
+    };
+}
+
+#[doc(hidden)]
+pub fn _print(args: ::core::fmt::Arguments) {
+    use core::fmt::Write;
+    SERIAL1.lock().write_fmt(args).expect("Serial print failed");
+}
+
+#[macro_export]
+macro_rules! serial_print {
+    ($($arg:tt)*) => {
+        $crate::serial::_print(format_args!($($arg)*));
+    };
+}
+
+#[macro_export]
+macro_rules! serial_println {
+    () => ($crate::serial_print!("\n"));
+    ($fmt:expr) => ($crate::serial_print!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => ($crate::serial_print!(
+            concat!($fmt, "\n"), $($arg)*));
+}

src/test_utils.rs

@@ -0,0 +1,54 @@
+#![cfg(test)]
+
+use core::panic::PanicInfo;
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    serial_println!("[failed]\n");
+    serial_println!("Error: {}", info);
+    exit_qemu(QemuExitCode::Failed);
+    loop {}
+}
+
+/// This function is hooked up to the #![test_runner] attribute made possible by the
+/// https://doc.rust-lang.org/unstable-book/language-features/custom-test-frameworks.html unstable
+/// feature. cf. https://os.phil-opp.com/testing/
+pub fn test_runner(tests: &[&dyn TestFunction]) {
+    serial_println!("Running {} test(s)", tests.len());
+    for test in tests {
+        test.run();
+    }
+
+    exit_qemu(QemuExitCode::Success);
+}
+
+pub trait TestFunction {
+    fn run(&self) -> ();
+}
+
+impl<T> TestFunction for T
+where
+    T: Fn(),
+{
+    fn run(&self) {
+        serial_print!("{}...\t", core::any::type_name::<T>());
+        self();
+        serial_println!("[ok]");
+    }
+}
+
+/// Exits qemu by writing to a special qemu emulated port.
+pub fn exit_qemu(exit_code: QemuExitCode) {
+    use x86_64::instructions::port::Port;
+    unsafe {
+        let mut port = Port::new(0xf4); // isa-debug-exit port, see Cargo.toml
+        port.write(exit_code as u32);
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u32)]
+pub enum QemuExitCode {
+    Success = 0x10,
+    Failed = 0x11,
+}

src/vga_buffer.rs

@@ -1,8 +1,6 @@
-use volatile::Volatile;
 use core::fmt;
-use spin::Mutex;
 use lazy_static::lazy_static;
-
+use spin::Mutex;
 
 #[macro_export]
 macro_rules! print {
@@ -18,10 +16,13 @@ macro_rules! println {
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
+    WRITER.lock().write_fmt(args).unwrap();
+    /*
     use x86_64::instructions::interrupts;
     interrupts::without_interrupts(|| {
       WRITER.lock().write_fmt(args).unwrap();
     });
+    */
 }
 
 #[allow(dead_code)]
@@ -48,97 +49,141 @@ pub enum Color {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(transparent)]
-struct ColorCode(u8);
+pub struct ColorCode(u8);
 
 impl ColorCode {
-  fn new(foreground: Color, background: Color) -> ColorCode {
-    ColorCode((background as u8) << 4 | (foreground as u8))
-  }
+    pub fn new(foreground: Color, background: Color) -> ColorCode {
+        ColorCode((background as u8) << 4 | (foreground as u8))
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(C)]
 struct ScreenChar {
-  ascii_char: u8,
-  color_code: ColorCode,
+    ascii_char: u8,
+    color_code: ColorCode,
 }
 
 const BUFFER_WIDTH: usize = 80;
 const BUFFER_HEIGHT: usize = 25;
 
 #[repr(transparent)]
-struct Buffer {
-  chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
+pub struct Buffer {
+    chars: [[ScreenChar; BUFFER_WIDTH]; BUFFER_HEIGHT],
 }
 
 pub struct Writer {
-  column_position: usize,
-  color_code: ColorCode,
-  buffer: &'static mut Buffer,
+    column_position: usize,
+    color_code: ColorCode,
+    buffer: &'static mut Buffer,
 }
 
 impl Writer {
-  pub fn write_string(&mut self, s: &str) {
-    for byte in s.bytes() {
-      match byte {
-        0x20..=0x7e | b'\n' => self.write_byte(byte),
-        _ => self.write_byte(0xfe), // a ■
-      }
-    }
-  }
-
-  pub fn write_byte(&mut self, byte: u8) {
-    match byte {
-      b'\n' => self.new_line(),
-      byte => {
-        if self.column_position >= BUFFER_WIDTH {
-          self.new_line();
+    pub fn new(color_code: ColorCode) -> Self {
+        Writer {
+            column_position: 0,
+            color_code,
+            buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
+        }
+    }
+    pub fn write_string(&mut self, s: &str) {
+        for byte in s.bytes() {
+            match byte {
+                0x20..=0x7e | b'\n' => self.write_byte(byte),
+                _ => self.write_byte(0xfe), // 0xfe is the character ■
+            }
         }
-        let row = BUFFER_HEIGHT - 1;
-        let col = self.column_position;
-        let color_code = self.color_code;
-        self.buffer.chars[row][col].write(ScreenChar {
-          ascii_char: byte, color_code,
-        });
-        self.column_position += 1;
-      }
     }
-  }
 
-  fn new_line(&mut self) {
-    for row in 1..BUFFER_HEIGHT {
-      for col in 0..BUFFER_WIDTH {
-        let character = self.buffer.chars[row][col].read();
-        self.buffer.chars[row - 1][col].write(character);
-      }
-    }
-    self.clear_row(BUFFER_HEIGHT - 1);
-    self.column_position = 0;
-  }
+    pub fn write_byte(&mut self, byte: u8) {
+        match byte {
+            b'\n' => self.new_line(),
+            byte => {
+                if self.column_position >= BUFFER_WIDTH {
+                    self.new_line();
+                }
+                let row = BUFFER_HEIGHT - 1;
+                let col = self.column_position;
+                let color_code = self.color_code;
 
-  fn clear_row(&mut self, row: usize) {
-    let blank = ScreenChar {
-      ascii_char: b' ',
-      color_code: self.color_code,
-    };
-    for col in 0..BUFFER_WIDTH {
-      self.buffer.chars[row][col].write(blank);
+                let ptr = &mut self.buffer.chars[row][col] as *mut ScreenChar;
+                let screenchar = ScreenChar {
+                    ascii_char: byte,
+                    color_code,
+                };
+
+                unsafe {
+                    core::ptr::write_volatile(ptr, screenchar);
+                }
+
+                self.column_position += 1;
+            }
+        }
+    }
+
+    fn new_line(&mut self) {
+        for row in 1..BUFFER_HEIGHT {
+            for col in 0..BUFFER_WIDTH {
+                let character = unsafe {
+                    core::ptr::read_volatile(&self.buffer.chars[row][col] as *const ScreenChar)
+                };
+
+                let ptr = &mut self.buffer.chars[row - 1][col] as *mut ScreenChar;
+                unsafe {
+                    core::ptr::write_volatile(ptr, character);
+                }
+            }
+        }
+        self.clear_row(BUFFER_HEIGHT - 1);
+        self.column_position = 0;
+    }
+
+    fn clear_row(&mut self, row: usize) {
+        let blank = ScreenChar {
+            ascii_char: b' ',
+            color_code: self.color_code,
+        };
+        for col in 0..BUFFER_WIDTH {
+            let ptr = &mut self.buffer.chars[row][col] as *mut ScreenChar;
+            unsafe {
+                core::ptr::write_volatile(ptr, blank);
+            }
+        }
     }
-  }
 }
 
 impl fmt::Write for Writer {
-  fn write_str(&mut self, s: &str) -> fmt::Result {
-    self.write_string(s);
-    Ok(())
-  }
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.write_string(s);
+        Ok(())
+    }
 }
 
-
 lazy_static! {
-  pub static ref WRITER: Mutex<Writer> = Mutex::new(Writer {
-    column_position: 0, color_code: ColorCode::new(Color::Yellow, Color::Black),
-    buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
-  });
+    pub static ref WRITER: Mutex<Writer> =
+        Mutex::new(Writer::new(ColorCode::new(Color::Yellow, Color::Black)));
 }
 
+#[test_case]
+fn test_println_simple() {
+    println!("Does this work?");
+}
+
+#[test_case]
+fn test_println_many() {
+    for _ in 0..200 {
+        println!("Test many output");
+    }
+}
+
+#[test_case]
+fn test_println_output() {
+    let s = "Test string that fits on a single line";
+    println!("{}", s);
+    for (i, c) in s.chars().enumerate() {
+        let screen_char_ptr =
+            &WRITER.lock().buffer.chars[BUFFER_HEIGHT - 2][i] as *const ScreenChar;
+        let screen_char = unsafe { core::ptr::read_volatile(screen_char_ptr) };
+        assert_eq!(char::from(screen_char.ascii_char), c);
+    }
+}