Crate polished_serial_logging

Expand description

§Serial Logging Library for x86_64 Kernels

This crate provides robust serial port logging for kernel and bootloader environments, with a focus on QEMU usage. It offers macros and functions for formatted and raw serial output, as well as a minimal kprint! macro for early boot or no_std contexts where dependencies are limited.

§QEMU Serial Logging

QEMU can redirect the guest’s serial port (COM1, 0x3F8) to the host’s standard output or a file. This allows you to see kernel logs by running QEMU with -serial stdio or -serial file:output.log. All output sent to the serial port will appear in your terminal or the specified file, making debugging much easier, especially before graphics or higher-level logging is available.

§When to Use `serial_log!`/`serial_print!` vs `kprint!`

Use serial_log!, serial_print!, and related macros for most kernel logging. These use a full-featured serial driver (with buffering, formatting, and thread safety) and are suitable once the kernel is initialized.
Use kprint! for minimal, dependency-free output in very early boot stages, or in environments where only core formatting is available. kprint! writes directly to the serial port using inline assembly, bypassing all higher-level abstractions.

§Features

Thread-safe, formatted serial output via serial_print!, serial_log!, etc.
Log level macros for info, warning, and error messages.
Hexadecimal logging support.
Minimal kprint! macro for direct serial output.
Enable/disable logging at runtime.

§Example (QEMU):

qemu-system-x86_64 -serial stdio -kernel path/to/kernel

In your kernel code:

use polished_serial_logging::{serial_println, serial_log};

serial_println!("Hello, QEMU serial!");
serial_log!("[INFO] ", "Boot complete");

Re-exports§

pub use crate::kprint::DebugSerial;

Modules§

kprint

Macros§

error: Logs an error-level message to the serial port with formatting support.
kprint: Minimal serial debug output for kernel/boot environments.
serial_log: Logs a message to the serial port with a given log level prefix.
serial_log_hex: Logs a hexadecimal value to the serial port with a given log level prefix.
serial_print: Prints to the host through the serial interface (COM1, 0x3F8).
serial_println: Prints to the host through the serial interface, appending a newline.

Structs§

SERIAL1

Functions§

disable_serial_logging: Disables serial logging output.
enable_serial_logging: Enables serial logging output.
error: Logs an error-level message to the serial port.
info: Logs an info-level message to the serial port.
info_hex: Logs an info-level hexadecimal value to the serial port.
is_serial_logging_enabled: Returns whether serial logging is currently enabled.
serial_write_byte: Writes a single byte to the serial port (COM1, 0x3F8).
serial_write_hex: Writes a hexadecimal representation of a u64 value to the serial port.
serial_write_str: Writes a string to the serial port, byte by byte.
warn: Logs a warning-level message to the serial port.