核心移植之Part1

 

 一. 知識要點：

1. 核心打補丁，編譯，UBOOT燒寫實驗 2. 核心功能，目錄結構核心菜單，驅動直接編譯進核心和模組概念，結合Makefile,Kconfig分析 3. 核心的啟動過程分析    3.1 核心產生過程解析    3.2 核心解壓縮、 vmlinux啟動流程（難，大致瞭解流程）    3.3 機器ID的比較    3.4 UBOOT參數傳遞的啟動參數解析    3.5 start_kernel()的典型過程            setup_arch()            rest_init()            驅動載入過程            根檔案系統掛載，第一個應用程式init的執行

二.核心的編譯過程

編譯:

1. make distclean (徹底清除所有編譯過程中產生的依賴和目標問題，不是每次都做)

2.準備核心配置.config

make fs2410_defconfig

   實際效果arch/arm/configs/fs2410_defconfig ====> .config

3. 編輯核心根目錄下的Makefile,添加體繫結構和交叉工具鏈定義

  ARCH            ?=arm

  CROSS_COMPILE   ?=arm-linux-gnu-

 也可以臨時指定的方式： make ARCH=arm CROSS_COMPILE=arm-linux-gnu- fs2410_defconfig

4.配置核心

  linux-2.6.22.6$ make menuconfig

    System Type  --->  ARM system type (Samsung S3C2410)  ---> 

    菜單中： * :直接編譯進核心   M: 不直接編譯進核心, XXX.ko, 目標板上： insmod xxxx.ko

    exit &save  (寫入.config)

make menuconfig的深入分析： make menuconfig實際執行: scripts/kconfig/mconf arch/arm/Kconfig # # using defaults found in .config # kernel中Makefile和Kconfig的規則： kbuild # # Ethernet (10 or 100Mbit) # CONFIG_NET_ETHERNET=y CONFIG_MII=y CONFIG_CIRRUS=y CONFIG_DM9000=y # CONFIG_SMC91X is not set Kconfig的文法規則  參考 Documentation\kbuild drivers/media/video/Kconfig 是一個好的例子   .config的作用 1.控制核心中某個檔案或者目錄是否編譯進核心 2.編譯過程中產生include/linux/autoconf.h， 通過這個autoconf.h控制我們核心中的.c檔案某一塊代碼是否編譯進核心

5.核心的編譯：

make uImage

make uImage V=1 (顯示詳細資料)

make uImage V=1 2>&1 |tee compile_log.txt （顯示詳細資料並記錄編譯過程到compile_log.txt）

三、核心的產生過程

arm-linux-gnu-ld -EL  -p --no-undefined -X -o vmlinux -T arch/arm/kernel/vmlinux.lds arch/arm/kernel/head.o arch/arm/kernel/init_task.o  init/built-in.o --start-group  usr/built-in.o  arch/arm/kernel/built-in.o  arch/arm/mm/built-in.o  arch/arm/common/built-in.o  arch/arm/mach-s3c2410/built-in.o  arch/arm/nwfpe/built-in.o  kernel/built-in.o  mm/built-in.o  fs/built-in.o  ipc/built-in.o  security/built-in.o  crypto/built-in.o  lib/lib.a  arch/arm/lib/lib.a  lib/built-in.o  arch/arm/lib/built-in.o  drivers/built-in.o  sound/built-in.o  net/built-in.o --end-group .tmp_kallsyms3.o ===>在核心的根目錄下產生vmlinux(~24M,ELF ) echo 'cmd_vmlinux := arm-linux-gnu-ld -EL  -p --no-undefined -X -o vmlinux -T arch/arm/kernel/vmlinux.lds arch/arm/kernel/head.o arch/arm/kernel/init_task.o  init/built-in.o --start-group  usr/built-in.o  arch/arm/kernel/built-in.o  arch/arm/mm/built-in.o  arch/arm/common/built-in.o  arch/arm/mach-s3c2410/built-in.o  arch/arm/nwfpe/built-in.o  kernel/built-in.o  mm/built-in.o  fs/built-in.o  ipc/built-in.o  security/built-in.o  crypto/built-in.o  lib/lib.a  arch/arm/lib/lib.a  lib/built-in.o  arch/arm/lib/built-in.o  drivers/built-in.o  sound/built-in.o  net/built-in.o --end-group .tmp_kallsyms3.o' > ./.vmlinux.cmd echo '  /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mksysmap System.map' && /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mksysmap vmlinux System.map; if [ $? -ne 0 ]; then rm -f vmlinux; /bin/false; fi;   /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mksysmap System.map echo '  /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mksysmap .tmp_System.map' && /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mksysmap .tmp_vmlinux3 .tmp_System.map   /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mksysmap .tmp_System.map cmp -s System.map .tmp_System.map || (echo Inconsistent kallsyms data; echo Try setting CONFIG_KALLSYMS_EXTRA_PASS; rm .tmp_kallsyms* ; /bin/false ) rm -f .old_version make -f scripts/Makefile.build obj=arch/arm/boot MACHINE=arch/arm/mach-s3c2410/ arch/arm/boot/uImage   arm-linux-gnu-objcopy -O binary -R .note -R .comment -S  vmlinux arch/arm/boot/Image   Kernel: arch/arm/boot/Image is ready make -f scripts/Makefile.build obj=arch/arm/boot/compressed arch/arm/boot/compressed/vmlinux   gzip -f -9 < arch/arm/boot/compressed/../Image > arch/arm/boot/compressed/piggy.gz   arm-linux-gnu-gcc -Wp,-MD,arch/arm/boot/compressed/.piggy.o.d  -nostdinc -isystem /opt/crosstool/gcc-3.4.5-glibc-2.3.6/arm-linux-gnu/lib/gcc/arm-linux-gnu/3.4.5/include -D__KERNEL__ -Iinclude  -mlittle-endian -D__ASSEMBLY__ -Wa,-L -gdwarf-2 -mapcs-32 -mno-thumb-interwork -D__LINUX_ARM_ARCH__=4 -march=armv4 -mtune=arm9tdmi -msoft-float    -c -o arch/arm/boot/compressed/piggy.o arch/arm/boot/compressed/piggy.S   arm-linux-gnu-ld -EL   --defsym zreladdr=0x30008000 --defsym params_phys=0x30000100 -p --no-undefined -X /opt/crosstool/gcc-3.4.5-glibc-2.3.6/arm-linux-gnu/lib/gcc/arm-linux-gnu/3.4.5/libgcc.a -T arch/arm/boot/compressed/vmlinux.lds arch/arm/boot/compressed/head.o arch/arm/boot/compressed/piggy.o arch/arm/boot/compressed/misc.o -o arch/arm/boot/compressed/vmlinux   arm-linux-gnu-objcopy -O binary -R .note -R .comment -S  arch/arm/boot/compressed/vmlinux arch/arm/boot/zImage   Kernel: arch/arm/boot/zImage is ready   /bin/sh /home/shyi/s3c2410/fs2410/kernel/linux-2.6.14/scripts/mkuboot.sh -A arm -O linux -T kernel -C none -a 0x30008000 -e 0x30008000 -n 'Linux-2.6.14' -d arch/arm/boot/zImage arch/arm/boot/uImage Image Name:   Linux-2.6.14 Created:      Wed Aug 31 15:08:47 2011 Image Type:   ARM Linux Kernel Image (uncompressed) Data Size:    1568348 Bytes = 1531.59 kB = 1.50 MB Load Address: 30008000 Entry Point:  30008000   Image arch/arm/boot/uImage is ready 注意： 要正確產生uImage, 必須先把u-boot編譯後的tools/mkimage 放到系統路徑下，比如/usr/bin目錄下

待續……