At 2012-11-27 13:10:37,"Kumar amit mehta" <gmate.amit@gmail.com> wrote:
On Tue, Nov 27, 2012 at 12:44:45PM +0800, horse_rivers wrote:
hi, when we compile kernel,gcc will put elf format information into the target file ,then we use build-tools construct the kernel Image, during this procedure,will elf information be copyed into Image file ?
Yes, it does but as you know that the kernel image will be in the compressed format, therefore you'll have to decompress it first. I tried following with my kernel image and then I was able to use the 'readelf' and 'objdump' on the extracted elf:
and this file can boot inux os ? if I put this file into floppy ,and boot from floppy ,can I boot this kernel ? thanks!
amit@ubuntu:/tmp$ cp /boot/vmlinuz-3.7.0-rc3-next-20121029 /tmp/ amit@ubuntu:/tmp$ od -A d -t x1 vmlinuz-3.7.0-rc3-next-20121029 | grep '1f 8b 08 00' 0016992 f3 a5 fc 5e 8d 83 b4 91 4f 00 ff e0 1f 8b 08 00 amit@ubuntu:/tmp$ dd if=vmlinuz bs=1 skip=17004 | zcat > vmlinux
How did i calculated 17004 ? 0016992 + offset of GZ signature(1f 8b 08 00), i.e. 0016992 + 12
amit@ubuntu:/tmp$ dd if=vmlinuz-3.7.0-rc3-next-20121029 bs=1 skip=17004 | zcat > vmlinux 5233764+0 records in 5233764+0 records out 5233764 bytes (5.2 MB) copied
amit@ubuntu:/tmp$ file vmlinux vmlinux: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, BuildID[sha1]=0xb874d61ffd40167270bdc1a95274976200223cc0, stripped
amit@ubuntu:/tmp$ objdump -f vmlinux
vmlinux: file format elf32-i386 architecture: i386, flags 0x00000102: EXEC_P, D_PAGED start address 0x01000000
For more information check the link [1] below.
- Amit
[1] http://forums.codeguru.com/showthread.php?415186-convert-vmlinuz-to-vmlinux