Trim unnecessary unsafe blocks

src/entry.rs

@@ -51,11 +51,25 @@ unsafe extern "C" fn _entry() {
         "csrw mstatus, t0",
         "csrw mie, x0",
 
-    );
+        "la t1, {kinit}",
+        "csrw mepc, t1",
 
-    // TODO do hardware inits and wake other harts
+        "la ra, 2f",
+        "mret",
+    "2:",
+        kinit = sym kinit,
+    );
 }
 
+#[no_mangle]
+extern "C" fn kinit() {
+    use crate::uart;
+    uart::Device::new(0x1000_0000);
+}
+
+#[no_mangle]
+extern "C" fn kinit_hart() {}
+
 #[inline]
 unsafe fn write_tp(id: &usize) {
     use core::arch::asm;

src/main.rs

@@ -96,7 +96,7 @@ extern "C" fn start() -> ! {
     // }
 
     // println!("This should not print because the console is not initialised.");
-    unsafe { uart::init_console(0x1000_0000) };
+    uart::init_console(0x1000_0000);
     println!("Hello, world!");
 
     // print current hartid

src/uart.rs

@@ -14,7 +14,7 @@ impl Device {
     /// Create a new UART device.
     /// # Safety
     /// `base` must be the base address of a UART device.
-    pub unsafe fn new(base: usize) -> Self {
+    pub fn new(base: usize) -> Self {
         use core::ptr::write_volatile;
         let addr = base as *mut u8;
         // Set data size to 8 bits.
@@ -64,9 +64,9 @@ impl core::fmt::Write for Device {
 /// Initialise the UART debugging console.
 /// # Safety
 /// `base` must point to the base address of a UART device.
-pub unsafe fn init_console(base: usize) {
-    let mut console = CONSOLE.lock();
-    *console = Some(unsafe { Device::new(base) });
+pub fn init_console(base: usize) {
+    let mut console: spinning_top::lock_api::MutexGuard<spinning_top::RawSpinlock, Option<Device>> = CONSOLE.lock();
+    *console = Some(Device::new(base));
 }
 
 /// Prints a formatted string to the [CONSOLE].