Adding new System Call to Linux Kernel 3.13 on 64 bit system -

Adding new System Call to Linux Kernel 3.13 on 64 bit system -

i'm trying add together simple helloworld scheme phone call kernel 3.13.0-37-generic on 64 bit system.

i'll seek show did far step step :

1- i've downloaded kernel source :

sudo apt-get source linux-image-3.13.0-37-generic

after that, kernel source files extracted /usr/src/

2- define new scheme phone call sys_hello() :

i've created directory hello name in kernel source directory in /usr/src/linux-3.13/

and created hello.c file in hello directory below content :

#include <linux/kernel.h> asmlinkage long sys_hello(void) { printk(“hello world\n”); homecoming 0; }

then created makefile in hello directory next content :

obj-y := hello.o

3- add together hello directory kernel’s makefile

i changed next line in /usr/src/linux-3.13/makefile:

core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/

to :

core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ hello/

4- add together new scheme phone call sys_hello() scheme phone call table (syscall_64.tbl file)

because i'm using 64 bit system, need alter syscall_64.tbl file in :

/usr/src/linux-3.13/arch/x86/syscalls/syscall_64.tbl

added next line in end of file :

-last line number 313

314 mutual hello sys_hello

5- add together new scheme phone call sys_hello() in scheme phone call header file

vim /usr/src/linux-3.13/include/linux/syscalls.h

i've added next line end of file before #endif statement @ bottom :

asmlinkage long sys_hello(void);

6- compiling kernel on system

to configure kernel tried next command :

sudo create menuconfig

after above command pop window came , made sure ext4 selected , save.

then :

# cd /usr/src/linux-3.13/ # create

it tooks 2~3 hours.

after :

# create modules_install install

after that, rebooted system.

7- test scheme phone call (problem here)

after reboot, created file name hello.c in home folder next content :

#include <stdio.h> #include <linux/kernel.h> #include <sys/syscall.h> #include <unistd.h> int main() { long int amma = syscall(314); // 314 number of sys_hello line in `syscall_64.tbl` printf(“system phone call sys_hello returned %ld\n”, amma); homecoming 0; }

then :

# gcc hello.c # ./a.out

the output :

system phone call sys_hello returned -1

problem -1. must homecoming 0 not -1.

seems sys_hello doesn't added kernel scheme call.

what doing wrong?

the problem step 6 lastly step (compile kernel).

after step 5, have next steps :

6- compiling kernel on system

to configure kernel tried next command :

# create menuconfig

after above command pop window came , made sure ext4 selected , save.

then create deb file new kernel have :

# create -j 5 kdeb_pkgversion=1.arbitrary-name deb-pkg

it create deb files in /usr/src/.

after need install them :

# dpkg -i linux*.deb

it install new kernel on system.

now, reboot system. after scheme rebooted can find out whether new kernel installed or not :

$ uname -r

and if want know new scheme phone call added kernel or not type :

$ cat /proc/kallsyms | grep <system phone call name>

in case :

$ cat /proc/kallsyms | grep hello

following output indicates scheme phone call added kernel :

0000000000000000 t sys_hello

linux linux-kernel system-calls