Merge pull request #3 from jimin-kiim/assignment-5

Assignment 5 Creating and Calling Own System Call

linux-5.4.214/include/linux/syscalls.h

@@ -1222,6 +1222,7 @@ asmlinkage long sys_old_mmap(struct mmap_arg_struct __user *arg);
  */
 asmlinkage long sys_ni_syscall(void);
 
+asmlinkage long sys_mycall(void);
 #endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
 
 

linux-5.4.214/include/uapi/asm-generic/unistd.h

@@ -850,10 +850,12 @@ __SYSCALL(__NR_pidfd_open, sys_pidfd_open)
 #define __NR_clone3 435
 __SYSCALL(__NR_clone3, sys_clone3)
 #endif
+#define __NR_mycall 460
+__SYSCALL(__NR_mycall, sys_mycall)
 
 #undef __NR_syscalls
-#define __NR_syscalls 436
-
+//#define __NR_syscalls 436
+#define __NR_syscalls 461
 /*
  * 32 bit systems traditionally used different
  * syscalls for off_t and loff_t arguments, while

linux-5.4.214/kernel/Makefile

@@ -10,7 +10,7 @@ obj-y     = fork.o exec_domain.o panic.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
+	    async.o range.o smpboot.o ucount.o my_syscall.o
 
 obj-$(CONFIG_MODULES) += kmod.o
 obj-$(CONFIG_MULTIUSER) += groups.o

linux-5.4.214/kernel/my_syscall.c

@@ -0,0 +1,7 @@
+#include <linux/syscalls.h>
+
+SYSCALL_DEFINE0(mycall)
+{       
+        printk("System Call Example!\n");
+        return 0;
+} 

syscall_example.c

@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include <sys/syscall.h>
+
+int main(void)
+{
+	long ret = syscall(460);
+	printf("System Call returned: %ld\n", ret);
+
+	return 0;
+}