Hi All,

 

I have Implemented sample system call on tree 3.4.6

Following are the steps i did -

- >I created directory hello in kernel sources base directory i.e /usr/src/kernels/linux3.4.6/hello

 

-> I have created hello.c file in which i added system call definition

#include <linux/kernel.h>

asmlinkage long sys_helloworld()

{

    printk(KERN_NOTICE "\n hello system call ");

   return 0;

}

 

In makefile

obj-y:= hello.c

 

-> In syscall tabel  arch/x86/syscalls/syscall_32.tbl

added - 

349 i386 helloworld sys_helloworld

 

Then compiled the kernel and installed it.

However when i run application strace ouput shows enosys(function not implemneted)

 

application as below

 

int main()

{

   syscall(349)

   return 0;

}

 

strace shows

SYS_349(0x1000,0x804843b,..,..,0)=-1 ENOSYS(function not implemneted)

 

I checked /proc/kallsyms it shows the sys_helloworld symbol

I also tried adding entry in syscall_64.tbl as common though i am running 32 bit kernel.

gdb syscall 349 doesnot give anything

 

Can anyone tell what is wrong here ?

 

Thanks,

-Ulka

 

 

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