The document provides instructions for compiling a custom Linux kernel and adding a new system call. It describes creating a new partition, mounting it, extracting and compiling the kernel source code. It also details adding a new system call to return a unique ID, including modifying configuration files, implementing the system call code, and testing the new system call. After compiling the kernel, the instructions describe installing modules, creating an initramfs, copying kernel files to the boot directory, and configuring GRUB to boot the new kernel.

1. /Log in info
user: student
pass: mt14Linux //(L)
//Get root permission
sudo su
// Create new partition
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sudo fdisk /dev/sdb1
Command (m for help ): m
Command (m for help ): n // enter to accept general of Properities
Command (m for help ): w
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// Create a file system on the new partition
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sudo mkfs.ext4 /dev/sdb1
$ mkdir /home/ student / ws_student
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// Mount the new partition to the mount point /home/student/ws_student
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$ sudo mount /dev/sdb1 /home/ student / ws_student
$ sudo chown student :users /home/ student /ws_student
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// Compilation and installation
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$ mkdir /home/student/iso
$ cd /home/student/iso
$ wget https://www.kernel.org/pub/linux/kernel/v4.x/linux-4.0.1.tar.xz
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// Extract the kernel and enter the source directory
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$ mkdir /home/student/ws_student/kernel
$ cd /home/student/ws_student/kernel
$ tar −xf /home/student/ iso /linux −4.x.x.tar.xz // push tab to auto fill the
directory
$ cd /home/student/ws_student/kernel/linux−4.x.x // push tab to auto fill the
directory
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// Build configuration-Configure your kernel (*** - very important !!!! )
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$ make nconfig
$ zcat /proc/config.gz >.config
$ make nconfig
General setup − − −>
(−ARCH) Local version − append to kernel release ’4.n.n−RCn’
( command for see username : uname -a )
>>>>>>>>>>>>>>WARNING. IF YOU DONT WANT TO WAIT FOR A LONG LONG LONG TIME
PLEASE<<<<<<<<<<<<<<<<<<<<
==================go to Step YOUR SYSTEM CALL fisrt Before you compile kernel
====================
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// Compile
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$ make −j 8
// core 2 duo - Ram 4GB - compiled for 2 hours dafuck ^^

2. //After Compile
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// Install modules
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$ sudo make modules_install
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// Make initial RAMdisk
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$ mkinitcpio −k KernelVersion −c / etc / mkinitcpio . conf −g /boot/ initramfs
−YourKernelName . img
// KernelVersion : use command ls to see
// YourKernelName : use command ls to see
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// Copy Kernel and related files to /boot directory
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$ cp −v arch /x86/boot/bzImage /boot/vmlinuz−YourKernelName
$ cp System .map /boot/System .map−YourKernelName
$ ln −sf /boot/System .map−YourKernelName /boot/System .map
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// Bootloader configuration
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// see your UUID
$ ls /dev/ disk /by−uuid/ −l
// e.g : /dev/sdb1 : UUID = 489b7153-a36c-4d51-a9af-bc7d21d2baa2
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// Edit grub.cfg to change your kernel name
cp /etc/grub.d/40_custom /boot/grub/custom.cfg
vi /boot/grub/custom.cfg
edit at line: menuentry "your kernel name"
linux /boot/vmlinuz-"your kernel name"
initrd /boot/initramfs-"youe kernelname".img
// run the following command to generate an updated /boot/grub/grub.cfg:
$ grub−mkconfig −o /boot/grub/grub.cfg (sometime that command do not need)
// Then save file custom.cfg and reboot. You will see your kernel
reboot
------------------------------------///-----------------------------------------
YOUR SYSTEM CALL
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requirement :
1. The system call should be named get_unique_id.c
2. It should take exactly one argument int *uuid which is the memory location
where
the unique identifer will be stored after the call
3. It should return long indicating the return value 0 for success and (minus)
error code otherwise.
4. The system call should check whether memory location supplied by the user is

3. valid and return -EFAULT otherwise. Consider using function put_user from
Step 1: arch/x86/entry/syscalls/syscall_32.tbl Added:
359 i386 get_unique_id sys_get_unique_id
Step 2: arch/x86/entry/syscalls/syscall_64.tbl Added:
546 x32 get_unique_id compat_sys_get_unique_id
Step 3: include/linux/syscalls.h Added prototype of my system call:
asmlinkage long sys_get_unique_id(int *uuid);
Step 4:
mkdir get_unique_id
nano get_unique_id/get_unique_id.c
Write your code here
#include <linux/linkage.h>
#include <linux/uaccess.h>
static int result = 0;
asmlinkage long sys_get_unique_id(int
*uuid)
{
result++;
int err = 0;
err = put_user(result, uuid);
return err ? -EFAULT : 0;
}
Step 5:
nano get_unique_id/Makefile
your code: obj-y :=get_unique_id.o
Step 6: nano Makefile
Crtl+W to sreach core-y
your code: usr/ get_unique_id/
>>>>>>>>>>>>>>Almost complete => Compile kernel and test your code<<<<<<<<<<<<
----------------------------------///-------------------------------------------
Test your system call
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# include <stdio.h>
# include <errno.h>
# include <sys/syscall.h>
# define IS_32_BIT 1
# if IS_32_BIT
# define __NR_get_unique_id 359
# else
# define __NR_get_unique_id 548
# endif
long get_unique_id ( int *uuid ) {
return syscall (__NR_get_unique_id , uuid ) ? errno : 0;
}

4. int main () {
int uuid ;
int res ;
res = get_unique_id (&uuid ) ;
printf("Syscall returned %d ,uuid is %dn",res,uuid ) ;
res = get_unique_id (&uuid ) ;
printf("Syscall returned %d,uuid is %dn",res,uuid ) ;
res = get_unique_id (47424742); // arbitrary memory address
printf("Syscall returned %dn",res ) ;
return 0 ;
}
Install GIT:
/usr/bin/dhcpcd (Connect to Internet by NAT)
sudo pacman -S git
sudo pacman -S gitk
git clone <url>
cp <>
git format-patch HEAD^
git commit -m "comment"
git push origin master
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-
Create the patch file
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-
1. Indexing modified files:
a) git add arch/x86/entry/syscalls/syscall_64.tbl
b) git add arch/x86/entry/syscalls/syscall_32.tbl
c) git add include/linux/syscalls.h
d) git add <Folder contains get_unique_id.c>/Makefile
e) git add <Folder contains get_unique_id.c>/get_unique_id.c
2. Create new HEAD in server git
a) git commit
b) Optional: You can use gitk (install to use) to check the HEAD
3. Create patch file.
a) git format_patch HEAD 1
b) sumbit patch file
------------------------------------------------------------------------------
bÆ°á»›c sau
------------------------------------------------------------------------------
//After Compile
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// Install modules
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$ sudo make modules_install
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// Make initial RAMdisk
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$ mkinitcpio â››k KernelVersion â››c / etc / mkinitcpio . conf â››g /boot/
initramfs â››YourKernelName . img
// KernelVersion : use command ls to see
// YourKernelName : use command ls to see
-------------------------------------------
// Copy Kernel and related files to /boot directory
-------------------------------------------

5. $ cp ∈v arch /x86/boot/bzImage /boot/vmlinuz∈YourKernelName
$ cp System .map /boot/System .map∈YourKernelName
$ ln ∈s f /boot/System .map∈YourKernelName /boot/System .map
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// Bootloader configuration
-------------------------------------------
// see your UUID
$ ls /dev/ disk /by∈uuid/ ∈l
// e.g : /dev/sdb1 : UUID = 489b7153-a36c-4d51-a9af-bc7d21d2baa2
-------------------------------------------
// Edit grub.cfg to change your kernel name
cp /etc/grub.d/40_custom /boot/grub/custom.cfg
vi /boot/grub/custom.cfg
edit at line: menuentry "your kernel name"
linux /boot/vmlinuz-"your kernel name"
initrd /boot/initramfs-"youe kernelname".img
// run the following command to generate an updated /boot/grub/grub.cfg:
$ grub∈mkconfig ∈o /boot/grub/grub.cfg (sometime that command do not need)
// Then save file custom.cfg and reboot. You will see your kernel
reboot

6. $ cp ∈v arch /x86/boot/bzImage /boot/vmlinuz∈YourKernelName
$ cp System .map /boot/System .map∈YourKernelName
$ ln ∈s f /boot/System .map∈YourKernelName /boot/System .map
-------------------------------------------
// Bootloader configuration
-------------------------------------------
// see your UUID
$ ls /dev/ disk /by∈uuid/ ∈l
// e.g : /dev/sdb1 : UUID = 489b7153-a36c-4d51-a9af-bc7d21d2baa2
-------------------------------------------
// Edit grub.cfg to change your kernel name
cp /etc/grub.d/40_custom /boot/grub/custom.cfg
vi /boot/grub/custom.cfg
edit at line: menuentry "your kernel name"
linux /boot/vmlinuz-"your kernel name"
initrd /boot/initramfs-"youe kernelname".img
// run the following command to generate an updated /boot/grub/grub.cfg:
$ grub∈mkconfig ∈o /boot/grub/grub.cfg (sometime that command do not need)
// Then save file custom.cfg and reboot. You will see your kernel
reboot