12 1 Embedded Software Lab. OS 실습 Embedded Software Lab. 박대준, 박은수 Lecture 3. Kernel fusing, printk

12 2 Embedded Software Lab. Cross Compiler 설치 & 코드 다운로드 Cross Compiler 설치 : $ sudo apt-get install gcc-arm-linux-gnueabihf 코드 저장 위치 설정 : $ cd $HOME $ mkdir work $ cd work 소스 코드 다운로드 : $ git clone --depth 1 -b odroid-3.8.y

12 3 Embedded Software Lab. compiling_a_Kernelhttp://odroid.us/mediawiki/index.php?title=Step-by-step_Cross- compiling_a_Kernel 참고 $ sudo apt-get install libncurses5-dev Toolchain  환경변수 설정  빌드 Cross-compile 설정

12 4 Embedded Software Lab. 커널 컴파일 $ cd linux-odroid-3.8.y/ $ export ARCH=arm $ export CROSS_COMPILE=arm-linux-gnue abihf- $ make odroidu_defconfig $ make zImage –j8 $ make modules

12 5 Embedded Software Lab. mkdir../rfs export INSTALL_MOD_PATH=$PWD/../rfs make modules_install cd../rfs # remove symlinks that point to files we do not need in root file system find. -name source | xargs rm find. -name build | xargs rm # Compress sudo tar -cvzf../modules.tgz. cd../ Module

12 6 Embedded Software Lab. Copy source_tree/arch/arm/boot/zImage to odroidu3:/boot/ zImage 설치

12 7 Embedded Software Lab. tar -xvzf modules.tgz rm modules.tgz sync reboot Module 설치

12 8 Embedded Software Lab. The kernel print function behaves almost identically to the C library printf() function callable from just about anywhere in the kernel at any time unusable before a certain point in the kernel boot process –early_printk() printk()

12 9 Embedded Software Lab. printk(" This is a warning!\n"); printk(" This is a debug notice!\n"); printk(" did not specify a loglevel!\n"); printk(KERN_WARNING "This is a warning!\n"); printk(KERN_DEBUG "This is a debug notice!\n"); printk("I did not specify a loglevel!\n"); printk-Loglevels

12 10 Embedded Software Lab. H/W