Homework1

 

System Environment :

VMware® Workstation - 7.0.0 build-203739
Ubuntu9.1 - Kernel2.6.31.14

1. Download Kernel 2.6

ftp://ftp.kernel.org/pub/linux/kernel/v2.6/
- Details : Use the Kernel 2.6.31.12
 I use it Although kernel versions released 2.6.32.xx. Because the kernel over 2.6.32.xx version is required higher version of GCC and diffrent setting of config installed on System.

2. Added Source Code

> tar -zxvf linux-2.6.31.12.tar.gz

The source code is added just before switch_to() function is called in context_switch() function in "kernel/sched.c" file.

#include <linux/kernel.h> #include <asm/processor.h> struct tss_struct *tss = &per_cpu(init_tss, get_cpu()); printk(KERN_INFO "ESP0 = %lx, SS0 = %8hx, ESP1   = %lx, SS1 = %8hx, ESP2 = %lx, SS2 = %8hx\n", tss->x86_tss.sp0, tss->x86_tss.ss0, tss->x86_tss.sp1, tss->x86_tss.ss1, tss->x86_tss.sp2, tss->x86_tss.ss2); printk(KERN_INFO "CR3  = %lx, EIP = %lx, EFLAGS = %lx, EAX = %lx, ECX  = %lx, EDX = %lx\n", tss->x86_tss.__cr3, tss->x86_tss.ip, tss->x86_tss.flags, tss->x86_tss.ax, tss->x86_tss.cx, tss->x86_tss.dx); printk(KERN_INFO "EBX  = %lx, ESP = %lx, EBP    = %lx, ESI = %lx, EDI  = %lx\n", tss->x86_tss.bx, tss->x86_tss.sp, tss->x86_tss.bp, tss->x86_tss.si, tss->x86_tss.di); printk(KERN_INFO "ES   = %8hx, CS  = %8hx, SS     = %8hx, DS  = %8hx, FS   = %8hx, GS  = %8hx, LDT = %8hx\n", tss->x86_tss.es, tss->x86_tss.cs, tss->x86_s.ss, tss->x86_tss.ds, tss->x86_tss.fs, tss->x86_tss.gs, tss->x86_tss.ldt);

I recommand you to refer to TSS(Task State Segment) in this blog.

 

 

 

3. Kernel Complie

> make menuconfig - Setting of environment you wanted
if you wanna use environment of current linux on system, copy the ".config" file.
As a fllowing command line :
    > cp /boot/config-2.6.31-14-generic /usr/src/linux-2.6.31.12/.config   
      (I was working on "/usr/src" directory)

> make
> make modules
> make modules_install
> make install

Otherwise,  If you use following commands, grub config is set automatically.
> make-kpkg -> Grub config auto setting
> dpkg

4. Setting grub

If you finish over the process, you can confirm that "System.map.-2.6.12" and "vmlinuz-2.6.31.12" files are generated.
But you may need img file of initrd to set config of grub.

How to make img file of initrd : 
 The Following command is used on Ubuntu System. But other systems(e.g. RedHat) use usally "mkinitrd" command.

 > update-initramfs -c -k 2.6.31.12

Next, you have to insert fllowing code to "/boot/grub/grub.cfg" or "grub.conf" or "menu.lsst"

### BEGIN /etc/grub.d/20_linux ### menuentry "Ubuntu, Linux 2.6.31.12" {         recordfail=1         if [ -n ${have_grubenv} ]; then save_env recordfail; fi  set quiet=1  insmod ext2  set root=(hd0,1)  search --no-floppy --fs-uuid --set c5ae961a-5dcc-4d7d-bdcb-7c5f097e3032  linux /boot/vmlinuz-2.6.31.12 root=UUID=c5ae961a-5dcc-4d7d-bdcb-7c5f097e3032 ro   quiet splash  initrd /boot/initrd.img-2.6.31.12 } menuentry "Ubuntu, Linux 2.6.31.12 (recovery mode)" {         recordfail=1         if [ -n ${have_grubenv} ]; then save_env recordfail; fi  insmod ext2  set root=(hd0,1)  search --no-floppy --fs-uuid --set c5ae961a-5dcc-4d7d-bdcb-7c5f097e3032  linux /boot/vmlinuz-2.6.31.12 root=UUID=c5ae961a-5dcc-4d7d-bdcb-7c5f097e3032 ro single  initrd /boot/initrd.img-2.6.31.12 } ### END /etc/grub.d/20_linux ###

5. Experimental Result

Restart System and Select kernel 2.6.31.12 at Boot menu.
Then, you can confirm that print the register information of TSS of a victim process to "/var/log/messages" in every context switch.

- Posted by Matia -