3. Test system call 추가

1. System Call 정의 <linux-nova/dedup/dedup.c>

#include<linux/kernel.h>
#include<linux/syscalls.h>

SYSCALL_DEFINE0(dedup){
	printk("dedup\n");
    return 0;
}

2. Makefile for system Call <linux-nova/dedup/Makefile>

obj-y := dedup.o

3. Makefile for "linux-nova" <linux-nova/Makefile>

...
core-y += kernel/ certs/ nm/ fs/ ipc/ security/ crypto/ block/ dedup/

4. System call header file <linux-nova/include/linux/syscalls.h>

...
asmlinkage long sys_dedup(void);
#endif

5. System call table <linux-nova/arch/x86/entry/syscalls/syscall_64.tbl>

...
333 common io_pgetevents __x64_sys_io_pgetevents
334 common rseq  __x64_sys_rseq
335 common dedup __x64_sys_dedup
...

after 'make' it will be added to <linux-nova/arch/x86/include/genereated/asm/syscalls_64.h>

6. Rebuild Kerenel

7. Test system call

#include <stdio.h>
#include <linux/kernel.h>
#include <sys/syscall.h>
#include <unistd.h>

int main() {
    long int temp = syscall(335);
    if(! temp){
        printf("System Call well Implemented! Returned: % ld\n", temp);
    }
    else {
        printf("Fail...\n");
    }
    return 0;
}

8. Result