freestanding rust binary, VGA, set up QEMU with serial port and isa-debug-exit, custom test framework

Author: criskell

.cargo/config.toml

@@ -0,0 +1,28 @@
+[build]
+target = "bare-metal-target.json"
+
+[unstable]
+build-std-features = ["compiler-builtins-mem"]
+build-std = ["core", "compiler_builtins"]
+
+[target.'cfg(target_os = "none")']
+runner = "bootimage runner"
+
+# isso aqui é para compilar um binário freestading para o sistema host
+# é melhor compilar para um target bare metal já que precisamos fazer outras coisas além disso, como inicializar a stack.
+
+# não linka com a rotina de startup padrão do runtime C
+
+# [target.'cfg(target_os = "linux")']
+# rustflags = ["-C", "link-arg=-nostartfiles"]
+
+# [target.'cfg(target_os = "windows")']
+# rustflags = ["-C", "link-args=/ENTRY:_start /SUBSYSTEM:console"]
+# espera a entrada dependendo do subsystem utilizado. ao especificar /ENTRY precisamos especificar o subsistema tbm que pode ser por ex WINDOWS ou CONSOLE.
+
+# [target.'cfg(target_os = "macos")']
+# rustflags = ["-C", "link-args=-e __start -static -nostartfiles"]
+
+# nostartfiles é para não linkar com o crt0 (c runtime zero).
+# _ adicional no nome do entrypoint é pq no mac as funções começam com _.
+# -static é para linkar um binário estático e não linçar com a lib libSystem.

.github/workflows/ci.yml

@@ -0,0 +1,26 @@
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out the code
+        uses: actions/checkout@v2
+      - name: Install QEMU
+        run: |
+          sudo apt-get update
+          sudo apt-get install qemu qemu-system-x86 qemu-utils
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+      - name: Install dependencies
+        run: |
+          cargo build
+      - name: Run tests
+        run: cargo test              

.gitignore

@@ -0,0 +1 @@
+/target

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+    "rust-analyzer.check.overrideCommand": [
+        "./cargo",
+        "xcheck",
+        "--json-output"
+    ]
+}

Cargo.lock

@@ -0,0 +1,32 @@
+[package]
+name = "osdev_rust"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+bootloader = "0.9"
+volatile = "0.2.6"
+spin = "0.5.2"
+x86_64 = "0.14.2"
+uart_16550 = "0.2.0"
+
+[dependencies.lazy_static]
+version = "1.0"
+features = ["spin_no_std"]
+
+# [profile.dev]
+# panic = "abort"
+
+[profile.release]
+panic = "abort"
+
+[package.metadata.bootimage]
+test-args = [
+    "-device",
+    "isa-debug-exit,iobase=0xf4,iosize=0x04",
+    "-serial",
+    "stdio",
+]
+# (0x10 << 1) | 1 = 32 | 1 = 33
+test-success-exit-code = 33
+test-timeout = 60           # 1 minute in seconds

Cargo.toml

@@ -0,0 +1,16 @@
+{
+    "llvm-target": "x86_64-unknown-none",
+    "data-layout": "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128",
+    "arch": "x86_64",
+    "target-endian": "little",
+    "target-pointer-width": "64",
+    "target-c-int-width": "32",
+    "os": "none",
+    "executables": true,
+    "linker-flavor": "ld.lld",
+    "linker": "rust-lld",
+    "panic-strategy": "abort",
+    "disable-redzone": true,
+    "features": "-mmx,-sse,+soft-float",
+    "rustc-abi": "x86-softfloat"
+}

bare-metal-target.json

@@ -0,0 +1 @@
+nightly

rust-toolchain

@@ -0,0 +1,84 @@
+#![feature(custom_test_frameworks)]
+#![test_runner(crate::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+#![no_std]
+#![no_main]
+
+mod serial;
+mod vga_buffer;
+
+use core::panic::PanicInfo;
+
+#[no_mangle]
+pub extern "C" fn _start() -> ! {
+    println!("Hello World!");
+
+    #[cfg(test)]
+    test_main();
+
+    loop {}
+}
+
+#[cfg(not(test))]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("{}", info);
+
+    loop {}
+}
+
+#[cfg(test)]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    serial_println!("[failed]\n");
+    serial_println!("Error: {}\n", info);
+    exit_qemu(QemuExitCode::Failed);
+    loop {}
+}
+
+pub trait Testable {
+    fn run(&self);
+}
+
+impl<T> Testable for T
+where
+    T: Fn(),
+{
+    fn run(&self) {
+        serial_print!("{}...\t", core::any::type_name::<T>());
+        self();
+        serial_println!("[ok]");
+    }
+}
+
+#[cfg(test)]
+pub fn test_runner(tests: &[&dyn Testable]) {
+    println!("Running {} tests", tests.len());
+
+    for test in tests {
+        test.run();
+    }
+
+    exit_qemu(QemuExitCode::Success);
+}
+
+#[test_case]
+fn trivial_assertion() {
+    assert_eq!(1, 1);
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u32)]
+pub enum QemuExitCode {
+    Success = 0x10,
+    Failed = 0x11,
+}
+
+pub fn exit_qemu(exit_code: QemuExitCode) {
+    use x86_64::instructions::port::Port;
+
+    unsafe {
+        let mut port = Port::new(0xf4);
+        port.write(exit_code as u32);
+    }
+}

src/main.rs

@@ -0,0 +1,41 @@
+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) };
+        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("Printing to serial port 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)*)
+    };
+}