kernel: logging

Cargo.lock

@@ -20,12 +20,19 @@ version = "0.1.0"
 dependencies = [
  "bit_field",
  "bitflags",
+ "log",
  "plain",
  "rbtree",
  "rustc-demangle",
  "seq-macro",
 ]
 
+[[package]]
+name = "log"
+version = "0.4.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ceec5bc11778974d1bcb055b18002eba7f4b3518b6a0081b3af5f21666da9ad"
+
 [[package]]
 name = "plain"
 version = "0.2.3"

kernel/Cargo.toml

@@ -24,6 +24,7 @@ harness = false
 [dependencies]
 bit_field = "0.10.3"
 bitflags = "2.13.1"
+log = { version = "0.4", default-features = false }
 seq-macro = "0.3.6"
 
 rbtree = { path = "../crates/rbtree" }

kernel/src/lib.rs

@@ -19,6 +19,7 @@ extern crate alloc;
 
 pub mod bits;
 pub mod limine;
+pub mod logger;
 pub mod serial;
 pub mod sync;
 pub mod x86_64;

kernel/src/logger.rs

@@ -0,0 +1,25 @@
+use log::{LevelFilter, Log, Metadata, Record};
+
+use crate::serial_println;
+
+pub struct SerialLogger;
+
+impl Log for SerialLogger {
+    fn enabled(&self, metadata: &Metadata<'_>) -> bool {
+        metadata.level() <= log::max_level()
+    }
+
+    fn log(&self, record: &Record<'_>) {
+        if self.enabled(record.metadata()) {
+            serial_println!("[{:}] {}", record.level(), record.args());
+        }
+    }
+
+    fn flush(&self) {}
+}
+
+pub fn init(max_level: LevelFilter) {
+    static LOGGER: SerialLogger = SerialLogger;
+    log::set_logger(&LOGGER).expect("logger already initialized");
+    log::set_max_level(max_level);
+}

kernel/src/main.rs

@@ -22,7 +22,7 @@ static GDT: LazyLock<GlobalDescriptorTable> = LazyLock::new(GlobalDescriptorTabl
 /// Entry point for the kernel
 #[unsafe(no_mangle)]
 extern "C" fn _start() -> ! {
-    kernel::serial_println!("Hello, world!");
+    kernel::logger::init(log::LevelFilter::Trace);
     assert!(limine_requests::LIMINE_BASE_REVISION.is_supported());
 
     _ = kernel::memory::HHDM_BASE
@@ -56,7 +56,6 @@ extern "C" fn _start() -> ! {
     GDT.load();
     IDT.load();
 
-    unsafe { (0 as *mut u8).write_volatile(0x42) };
 
     kernel::serial_println!("entry point: 0x{:x}", _start as *const () as usize);
     kernel::serial_println!(