linux核心的生成過程, vmlinux除錯分析
阿新 • • 發佈：2019-01-01
1. 依據arch/arm/kernel/vmlinux.lds 生成linux核心原始碼根目錄下的vmlinux，這個vmlinux屬於未壓縮，帶除錯資訊、符號表的最初的核心，大小約23MB；
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_kallsyms2.o
2.將上面的vmlinux去除除錯資訊、註釋、符號表等內容，生成arch/arm/boot/Image，這是不帶多餘資訊的linux核心，Image的大小約3.2MB；
命令:arm-linux-gnu-objcopy -O binary -R .note -R .comment -S vmlinux arch/arm/boot/Image
3. 將 arch/arm/boot/Image 用gzip -9 壓縮生成arch/arm/boot/compressed/piggy.gz大小約1.5MB；
命令:gzip -f -9 < arch/arm/boot/compressed/../Image > arch/arm/boot/compressed/piggy.gz
4. 編譯arch/arm/boot/compressed/piggy.S 生成arch/arm/boot/compressed/piggy.o大小約1.5MB，這裡實際上是將piggy.gz通過piggy.S編譯進piggy.o檔案中。而piggy.S檔案僅有6行，只是包含了檔案piggy.gz;
命令:arm-linux-gnu-gcc -Wp,-MD,arch/arm/boot/compressed/.piggy.o.d -nostdinc -isystem /home/justin/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
5.依據arch/arm/boot/compressed/vmlinux.lds 將arch/arm/boot/compressed/目錄下的檔案head.o 、piggy.o 、misc.o連結生成 arch/arm/boot/compressed/vmlinux，這個vmlinux是經過壓縮且含有自解壓程式碼的核心,大小約1.5MB;
命令:arm-linux-gnu-ld -EL --defsym zreladdr=0x30008000 --defsym params_phys=0x30000100 -p --no-undefined -X /home/justin/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
6.將arch/arm/boot/compressed/vmlinux去除除錯資訊、註釋、符號表等內容，生成arch/arm/boot/zImage大小約1.5MB;這已經是一個可以使用的linux核心映像檔案了；
命令:arm-linux-gnu-objcopy -O binary -R .note -R .comment -S arch/arm/boot/compressed/vmlinux arch/arm/boot/zImage
7.將arch/arm/boot/zImage新增64Bytes的相關資訊打包為arch/arm/boot/uImage大小約1.5MB;
命令:/bin/sh /home/farsight/Resources/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
