A nix flake dedicated to making the developer tooling around kernel development easier.
- Compile a local copy of the linux kernel located unter ./linux
- QEMU VM support using Nix's built in functions for generating an initramfs
- Remote GDB debugging through the VM
Get started by cloning this repository.
git clone git@github.com:fxttr/kernel
cd kernel
git clone --depth 1 git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git linux
# nix develop .# or direnv allow to get into the dev environment
runvm # Calls QEMU with the necessary commands, uses sudo for enabling kvm
#### Inside QEMU
# insmod module/helloworld.ko # Load the kernel module
# rmmod module/helloworld.ko # Unload the module
#### C^A+X to exit
#### In another terminal while the VM is running
# rungdb # Connect to the VM with remote GDB debugging
### (GDB)
## lx-symbols-nix # Runs lx-symbols with the nix store paths of the modules
####
cd linux
bear -- make # generate the compile_commands.json
# exit and then nix develop .# or just direnv reload
# to rebuild and update the runvm commandRemote GDB debugging is activated through the rungdb command (build/run-gdb.nix). It wraps GDB to provide the kernel source in the search path, loads vmlinux, sources the kernel gdb scripts, and then connects to the VM. An alias is provided lx-symbols-nix that runs the lx-symbols command with all the provided modules' nix store paths as search directories.
The initial ram disk is built using the new make-initrd-ng. It is called through its nix wrapper which safely copies the nix store packages needed over. To see how to include modules and other options see the builder, build/initramfs.nix.
Clang-format was copied over from the linux source tree. To get CCLS working correctly call bear -- make to get a compile_commands.json. Then open up C files.
If you have nix-direnv enabled a shell with everything you need should open when you cd into the directory after calling direnv allow