Hi Ulka, You need to add edit two more files. Add the following in file "arch/x86/include/generated/uapi/asm/unistd_32.h": #define __NR_helloworld 349 Add the following in "include/linux/syscalls.h" : asmlinkage long sys_helloworld(void); Regards, Binoy Jayan Mob: +91-9742870916, +91-9745783048 ________________________________________ From: kernelnewbies-bounces@kernelnewbies.org [kernelnewbies-bounces@kernelnewbies.org] on behalf of Ulka Vaze [ulka.vaze@l2it.com] Sent: Thursday, October 10, 2013 4:47 PM To: Kernelnewbies@kernelnewbies.org Subject: system call does not work 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 main makefile added directory in core-y -> 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 -- Director L2IT -Learn & Leverage Information Technology Leading Professional Training Institute in Pune www.l2it.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Please do not print this email unless it is absolutely necessary. The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com