Yet Another Linux Development Approach

Prepare environment

Ubuntu:

$ sudo apt install kconfig-frontends

Others:

$ git clone https://github.com/jameswalmsley/kconfig-frontends
$ cd kconfig-frontends
$ ./bootstrap
$ ./configure
$ make -j$(nproc)
$ sudo make install

Configure YALDA

• generate .config file

$ make menuconfig

• you can set environment variables by yourself:

$ export ROOTFS_OUT=/mnt/iniitrd.cpio.gz
$ export KERNEL_DIR=/mnt/linux-5.14
$ export KERNEL_SOURCE=git
$ make build

Build components

• Build all components:

$ make build

• You can build separate component
• You can pass env variables before or inside make build-* call

$ make build-kernel
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- build-kernel
$ BUSYBOX_DIR=./new-busybox BUSYBOX_SOURCE=git make build-busybox
$ make build-whistle
$ make ROOTFS_OUT=/mnt/initrd.cpio.gz  build-rootfs
$ ...

Quick start

• call make run-qemu
• run gdb (i.e make run-gdb)
• attach the kernel via target remote :1234
• add breakpoint b do_init_module
• load symbols lx-symbols <PATH TO YOUR MODULE>
• add breakpoint to you module functions. (make sure __init attribure is not used for your module init function)
• enjoy

Also you can use the current host kernel: you need to select CONFIG_YALDA_RUN_HOST_KERNEL (run - host kernel in menuconfig). Then run make run-qemu and make run-gdb. Please note that you need to set YALDA_KERNEL_VMLINUX_PATH to your vmlinux path. Propably you will also need to install a kernel debug symbols package for your distribution.

Description

See scripts please. It is easy Useful things:

• it mounts ./ path to /mnt/share inside QEMU
• it create and mounts home path to /home and set it as $HOME
• in order to exit use ctrl-a-x
• in order to enter QEMU console use ctrl-a-c
• uncomment -S in order to debug kernel from early begining

Known issues

• ctrl-c does not work in ash scripts