멈춤보단 천천히라도

pi@raspberrypi:~ $ uname -r
4.9.60-v7+

#define __NR_copy_file_range            (__NR_SYSCALL_BASE+391)
#define __NR_preadv2                    (__NR_SYSCALL_BASE+392)
#define __NR_pwritev2                   (__NR_SYSCALL_BASE+393)
#define __NR_pkey_mprotect              (__NR_SYSCALL_BASE+394)
#define __NR_pkey_alloc                 (__NR_SYSCALL_BASE+395)
#define __NR_pkey_free                  (__NR_SYSCALL_BASE+396)
#define __NR_helloworld                 (__NR_SYSCALL_BASE+397)

/*
* This may need to be greater than __NR_last_syscall+1 in order to
* account for the padding in the syscall table
*/
#define __NR_syscalls  (400)

/* 390 */       CALL(sys_mlock2)
               CALL(sys_copy_file_range)
               CALL(sys_preadv2)
               CALL(sys_pwritev2)
               CALL(sys_pkey_mprotect)
/* 395 */       CALL(sys_pkey_alloc)
               CALL(sys_pkey_free)
               CALL(sys_helloworld)

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



asmlinkage long sys_helloworld(void)
{
   printk( "[sys_helloworld] Hello World\n" );

   return 0;
}

#
# Makefile for the linux kernel.
#

obj-y     = fork.o exec_domain.o panic.o \
           cpu.o exit.o softirq.o resource.o \
           sysctl.o sysctl_binary.o capability.o ptrace.o user.o \
           signal.o sys.o kmod.o workqueue.o pid.o task_work.o \
           extable.o params.o \
           kthread.o sys_ni.o nsproxy.o \
           notifier.o ksysfs.o cred.o reboot.o \
           async.o range.o smpboot.o ucount.o helloworld.o

$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- zImage  -j4

$ scp arch/arm/boot/zImage  pi@192.168.43.142:/home/pi

pi@raspberrypi:~ $ sudo cp zImage /boot/kernel7.img

#include <stdio.h>
#include <linux/unistd.h>
#define __NR_helloworld 397


void main()
{
      syscall( __NR_helloworld );
}

[  135.364935] [sys_helloworld] Hello World