85 lines
No EOL
1.9 KiB
Markdown
85 lines
No EOL
1.9 KiB
Markdown
## Setup env
|
|
|
|
On NixOS:
|
|
|
|
- Ensure Linux Kernel is the same as you configuration.
|
|
Otherwise, change linux_dev variable with you kernel variant and change flake.lock nixpkgs with your version.
|
|
- Use direnv allow or nix develop to setup shell.
|
|
|
|
|
|
On other distros:
|
|
|
|
1. With direnv, in .envrc, change line by `use flake .#other`
|
|
|
|
2. With nix only, use `nix develop .#other`
|
|
|
|
3. Otherwise, you need to setup LINUX_MODULES_FOLDER to linux modules folder of your distro (ex: `/lib/modules/$(uname -r)`) in your shell (ex: .bashrc)
|
|
|
|
## make : targets list
|
|
|
|
- all : Compiling kernel (by default)
|
|
- clean : Cleaning build folder
|
|
|
|
All subfolder is configured to use LINUX_MODULES_FOLDER env variable set by flake develop
|
|
|
|
## How test module
|
|
|
|
Step 1: Load module
|
|
|
|
```bash
|
|
sudo insmod [module_name].ko
|
|
```
|
|
|
|
**Warning**: Can fail if secure boot is enabled (see notes about secure boot in below)
|
|
|
|
Step 2: Check logs
|
|
|
|
```bash
|
|
sudo dmesg | tail
|
|
```
|
|
|
|
Step 3: Unload module
|
|
|
|
```bash
|
|
sudo rmmod [module_name].ko
|
|
```
|
|
|
|
## Usefull links
|
|
|
|
- https://www.kernel.org/doc/html/latest/
|
|
- https://elixir.bootlin.com/linux/v6.13/source/
|
|
|
|
## Notes
|
|
|
|
1. Find required headers files
|
|
|
|
```
|
|
nix shell nixpkgs#bear
|
|
cd 01_basic_module/
|
|
bear --append --output ../.vscode/compile_commands.json -- make -C $LINUX_MODULES_FOLDER/build M=$PWD modules
|
|
```
|
|
|
|
Search -I args and -D args
|
|
|
|
### Sign kernel module for testing with secure boot enabled
|
|
|
|
Prerequisites: Own secure boot keys configured.
|
|
|
|
Secure boot keys can be found in :
|
|
|
|
- Fedora : `/etc/pki/akmods`
|
|
- With sbctl : `/var/lib/sbctl`
|
|
|
|
```
|
|
sign-file sha256 $SECUREBOOT_KEYS_PATH/private_key.priv $SECUREBOOT_KEYS_PATH/public_key.der <module_file>.ko
|
|
```
|
|
|
|
sign-file executable is in `/usr/src/kernels/$(uname -r)/scripts`
|
|
|
|
Full example (run as root):
|
|
|
|
1. Fedora
|
|
|
|
```bash
|
|
/usr/src/kernels/$(uname -r)/scripts/sign-file sha256 /etc/pki/akmods/private/private_key.priv /etc/pki/akmods/certs/public_key.der <module_file>.ko
|
|
``` |