Add new system call

kernel版本:2.6.33-rc2

新增自行定義的system call步驟如下:

1. edit arch/x86/kernel/syscall_table_32.S, add

.long sys_mysystemcall /* 338 */

2. edit include/asm-i386/unistd.h, add

#define __NR_mysystemcall 338

3. create new file, arch/x86/kernel/systemcall.c
(defined filename yourself)

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

asmlinkage int sys_mysystemcall(void)
{
printk("mysystemcall\n");
return 0;
}

4. edit arch/x86/kernel/Makefile, add

obj-y += systemcall.o


5. compiler kernel

root@shulong-desktop:/home/shulong/linux-2.6.33-rc2# make clean && make


6. writing code for user mode, create new file test.c

#include <linux/unistd.h>
#include <sys/syscall.h>
#include <sys/types.h>

#define __NR_mysystemcall 338
#define mysystemcall() syscall(__NR_mysystemcall);

int main ()
{
mysystemcall();
return 0;
}

7. compiler test.c

root@shulong-desktop:~# gcc -Wall test.c -o systemcall

8. execute systemcall

root@shulong-desktop:~# ./systemcall
[ 39.289669] mysystemcall


就可順利加入自行定義的system call。