Hello World on simulator

.cargo/config.toml

@@ -0,0 +1,5 @@
+[build]
+target = "aarch64-unknown-none"
+
+[target.aarch64-unknown-none]
+rustflags = ["-C", "link-arg=-Tlink.ld"]

.gitignore

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

.vscode/launch.json

@@ -0,0 +1,25 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Attach to QEMU (AArch64)",
+      "type": "cppdbg",
+      "request": "launch",
+      "program": "${workspaceFolder}/target/aarch64-unknown-none/debug/nova",
+      "miDebuggerServerAddress": "localhost:1234",
+      "miDebuggerPath": "gdb",
+      "cwd": "${workspaceFolder}",
+      "stopAtEntry": true,
+      "externalConsole": false,
+      "MIMode": "gdb",
+      "setupCommands": [
+        {
+          "description": "Enable pretty-printing for gdb",
+          "text": "-enable-pretty-printing",
+          "ignoreFailures": true
+        }
+      ],
+      "preLaunchTask": "Run QEMU"
+    }
+  ]
+}

.vscode/tasks.json

@@ -0,0 +1,21 @@
+{
+  "version": "2.0.0",
+  "tasks": [
+    {
+      "label": "Build",
+      "type": "shell",
+      "command": "cargo build --target aarch64-unknown-none",
+      "args": [],
+      "group": {
+        "kind": "build",
+        "isDefault": true
+      }
+    },
+    {
+      "label": "Run QEMU",
+      "type": "shell",
+      "command": "qemu-system-aarch64 -M raspi3b -cpu cortex-a72 -display none -kernel ${workspaceFolder}/target/aarch64-unknown-none/debug/nova -s -S",
+      "isBackground": true
+    }
+  ]
+}

Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "nova"
+version = "0.1.0"

Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "nova"
+version = "0.1.0"
+edition = "2021"
+
+
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+panic = "abort"

link.ld

@@ -0,0 +1,19 @@
+SECTIONS
+{
+    . = 0x80000;     /* Kernel load address for AArch64 */
+    .text : { KEEP(*(.text.boot)) *(.text .text.* .gnu.linkonce.t*) }
+    .rodata : { *(.rodata .rodata.* .gnu.linkonce.r*) }
+    PROVIDE(_data = .);
+    .data : { *(.data .data.* .gnu.linkonce.d*) }
+    .bss (NOLOAD) : {
+        . = ALIGN(16);
+        __bss_start = .;
+        *(.bss .bss.*)
+        *(COMMON)
+        __bss_end = .;
+    }
+    _end = .;
+
+   /DISCARD/ : { *(.comment) *(.gnu*) *(.note*) *(.eh_frame*) }
+}
+__bss_size = (__bss_end - __bss_start)>>3;

rust-toolchain.toml

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly"

src/main.rs

@@ -0,0 +1,42 @@
+#![no_main]
+#![no_std]
+#![feature(asm_experimental_arch)]
+
+use core::{
+    arch::asm,
+    fmt::{self, Write},
+    panic::PanicInfo,
+};
+
+#[panic_handler]
+fn panic(_panic: &PanicInfo) -> ! {
+    loop {}
+}
+
+const UART0_DR: u32 = 0x3F20_1000;
+
+struct Uart;
+
+impl Write for Uart {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        for byte in s.bytes() {
+            unsafe {
+                core::ptr::write_volatile(UART0_DR as *mut u8, byte);
+            }
+        }
+        Ok(())
+    }
+}
+
+#[no_mangle]
+#[unsafe(naked)]
+pub extern "C" fn _start() -> ! {
+    core::arch::naked_asm!("mov sp, #0x80000", "bl main");
+}
+
+#[no_mangle]
+fn main() {
+    let mut uart = Uart {};
+    writeln!(uart, "Hello World!\n");
+    loop {}
+}

tools/start_simulator.sh

@@ -0,0 +1,3 @@
+cd "$(dirname "$0")"
+
+qemu-system-aarch64 -M raspi3b -cpu cortex-a53 -serial stdio -display none -kernel ../target/aarch64-unknown-none/debug/nova -s