Rust for Kernel Module

Outline

• about kernel module
• add a new module in rust

About Kernel Module

Lifetime of kernel module

• init when being loaded

• register to the certain subsystem

• when receive some action from an actor

• subsystem perform a callback to the module

• then returns

……

• when unload
• unregister to subsystem

What we’re going to build

some /dev/scull0, /dev/scull1, … that are readable and writeable TODO

Development workflow

• do some change to kernel src
• boot with qemu with busybox, resources can be found Debug Linux Kernel & Rust for Linux
• and debug it through remote gdb

Add a New Module

modify Kconfig and Makefile

• add the Kconfig at linux/samples/rust/Kconfig for our new module:

config SAMPLE_RUST_SCULL
	tristate "Scull module"
	help
	  This option builds the Rust scull module sample.

	  To compile this as a module, choose M here:
	  the module will be called rust_scull.

	  If unsure, say N.

• add the compile command for our new module at linux/samples/rust/Makefile:

obj-$(CONFIG_SAMPLE_RUST_SCULL)			+= rust_scull.o

• create the file

touch linux/samples/rust/rust_scull.rs

• enable this in menuconfig
• then it should compiles
• remember to use make LLVM=1 rust-analyzer to generate index for lsp

Edit our module

in linux/samples/rust/rust_scull.rs

//! Scull module in Rust

use kernel::prelude::*;

module! {
    type: Scull,
    name: "scull",
    license: "GPL",
}

struct Scull;

impl kernel::Module for Scull {
    fn init(_module: &'static ThisModule) -> kernel::error::Result<Self> {
	    pr_info!("Hello World\n");
        Ok(Scull)
    }
}

now it can be compiled, you can see the hello world from our module by dmesg