1. 根目录:
2. kernel
3. sys_ni.c

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

#include <asm/unistd.h>

/*  we can't #include <linux/syscalls.h> here,
    but tell gcc to not warn with -Wmissing-prototypes  */
asmlinkage long sys_ni_syscall(void);

/*
 * Non-implemented system calls get redirected here.
 */
asmlinkage long sys_ni_syscall(void)
{
	return -ENOSYS;
}

cond_syscall(sys_quotactl);
cond_syscall(sys32_quotactl);
cond_syscall(sys_acct);
cond_syscall(sys_lookup_dcookie);
cond_syscall(compat_sys_lookup_dcookie);
cond_syscall(sys_swapon);
cond_syscall(sys_swapoff);
cond_syscall(sys_kexec_load);
cond_syscall(compat_sys_kexec_load);
cond_syscall(sys_kexec_file_load);
cond_syscall(sys_init_module);
cond_syscall(sys_finit_module);
cond_syscall(sys_delete_module);
cond_syscall(sys_socketpair);
cond_syscall(sys_bind);
cond_syscall(sys_listen);
cond_syscall(sys_accept);
cond_syscall(sys_accept4);
cond_syscall(sys_connect);
cond_syscall(sys_getsockname);
cond_syscall(sys_getpeername);
cond_syscall(sys_sendto);
cond_syscall(sys_send);
cond_syscall(sys_recvfrom);
cond_syscall(sys_recv);
cond_syscall(sys_socket);
cond_syscall(sys_setsockopt);
cond_syscall(compat_sys_setsockopt);
cond_syscall(sys_getsockopt);
cond_syscall(compat_sys_getsockopt);
cond_syscall(sys_shutdown);
cond_syscall(sys_sendmsg);
cond_syscall(sys_sendmmsg);
cond_syscall(compat_sys_sendmsg);
cond_syscall(compat_sys_sendmmsg);
cond_syscall(sys_recvmsg);
cond_syscall(sys_recvmmsg);
cond_syscall(compat_sys_recvmsg);
cond_syscall(compat_sys_recv);
cond_syscall(compat_sys_recvfrom);
cond_syscall(compat_sys_recvmmsg);
cond_syscall(sys_socketcall);
cond_syscall(sys_futex);
cond_syscall(compat_sys_futex);
cond_syscall(sys_set_robust_list);
cond_syscall(compat_sys_set_robust_list);
cond_syscall(sys_get_robust_list);
cond_syscall(compat_sys_get_robust_list);
cond_syscall(sys_epoll_create);
cond_syscall(sys_epoll_create1);
cond_syscall(sys_epoll_ctl);
cond_syscall(sys_epoll_wait);
cond_syscall(sys_epoll_pwait);
cond_syscall(compat_sys_epoll_pwait);
cond_syscall(sys_semget);
cond_syscall(sys_semop);
cond_syscall(sys_semtimedop);
cond_syscall(compat_sys_semtimedop);
cond_syscall(sys_semctl);
cond_syscall(compat_sys_semctl);
cond_syscall(sys_msgget);
cond_syscall(sys_msgsnd);
cond_syscall(compat_sys_msgsnd);
cond_syscall(sys_msgrcv);
cond_syscall(compat_sys_msgrcv);
cond_syscall(sys_msgctl);
cond_syscall(compat_sys_msgctl);
cond_syscall(sys_shmget);
cond_syscall(sys_shmat);
cond_syscall(compat_sys_shmat);
cond_syscall(sys_shmdt);
cond_syscall(sys_shmctl);
cond_syscall(compat_sys_shmctl);
cond_syscall(sys_mq_open);
cond_syscall(sys_mq_unlink);
cond_syscall(sys_mq_timedsend);
cond_syscall(sys_mq_timedreceive);
cond_syscall(sys_mq_notify);
cond_syscall(sys_mq_getsetattr);
cond_syscall(compat_sys_mq_open);
cond_syscall(compat_sys_mq_timedsend);
cond_syscall(compat_sys_mq_timedreceive);
cond_syscall(compat_sys_mq_notify);
cond_syscall(compat_sys_mq_getsetattr);
cond_syscall(sys_mbind);
cond_syscall(sys_get_mempolicy);
cond_syscall(sys_set_mempolicy);
cond_syscall(compat_sys_mbind);
cond_syscall(compat_sys_get_mempolicy);
cond_syscall(compat_sys_set_mempolicy);
cond_syscall(sys_add_key);
cond_syscall(sys_request_key);
cond_syscall(sys_keyctl);
cond_syscall(compat_sys_keyctl);
cond_syscall(compat_sys_socketcall);
cond_syscall(sys_inotify_init);
cond_syscall(sys_inotify_init1);
cond_syscall(sys_inotify_add_watch);
cond_syscall(sys_inotify_rm_watch);
cond_syscall(sys_migrate_pages);
cond_syscall(sys_move_pages);
cond_syscall(sys_chown16);
cond_syscall(sys_fchown16);
cond_syscall(sys_getegid16);
cond_syscall(sys_geteuid16);
cond_syscall(sys_getgid16);
cond_syscall(sys_getgroups16);
cond_syscall(sys_getresgid16);
cond_syscall(sys_getresuid16);
cond_syscall(sys_getuid16);
cond_syscall(sys_lchown16);
cond_syscall(sys_setfsgid16);
cond_syscall(sys_setfsuid16);
cond_syscall(sys_setgid16);
cond_syscall(sys_setgroups16);
cond_syscall(sys_setregid16);
cond_syscall(sys_setresgid16);
cond_syscall(sys_setresuid16);
cond_syscall(sys_setreuid16);
cond_syscall(sys_setuid16);
cond_syscall(sys_sgetmask);
cond_syscall(sys_ssetmask);
cond_syscall(sys_vm86old);
cond_syscall(sys_vm86);
cond_syscall(sys_ipc);
cond_syscall(compat_sys_ipc);
cond_syscall(compat_sys_sysctl);
cond_syscall(sys_flock);
cond_syscall(sys_io_setup);
cond_syscall(sys_io_destroy);
cond_syscall(sys_io_submit);
cond_syscall(sys_io_cancel);
cond_syscall(sys_io_getevents);
cond_syscall(sys_sysfs);
cond_syscall(sys_syslog);
cond_syscall(sys_process_vm_readv);
cond_syscall(sys_process_vm_writev);
cond_syscall(compat_sys_process_vm_readv);
cond_syscall(compat_sys_process_vm_writev);
cond_syscall(sys_uselib);
cond_syscall(sys_fadvise64);
cond_syscall(sys_fadvise64_64);
cond_syscall(sys_madvise);
cond_syscall(sys_setuid);
cond_syscall(sys_setregid);
cond_syscall(sys_setgid);
cond_syscall(sys_setreuid);
cond_syscall(sys_setresuid);
cond_syscall(sys_getresuid);
cond_syscall(sys_setresgid);
cond_syscall(sys_getresgid);
cond_syscall(sys_setgroups);
cond_syscall(sys_getgroups);
cond_syscall(sys_setfsuid);
cond_syscall(sys_setfsgid);
cond_syscall(sys_capget);
cond_syscall(sys_capset);

/* arch-specific weak syscall entries */
cond_syscall(sys_pciconfig_read);
cond_syscall(sys_pciconfig_write);
cond_syscall(sys_pciconfig_iobase);
cond_syscall(compat_sys_s390_ipc);
cond_syscall(ppc_rtas);
cond_syscall(sys_spu_run);
cond_syscall(sys_spu_create);
cond_syscall(sys_subpage_prot);
cond_syscall(sys_s390_pci_mmio_read);
cond_syscall(sys_s390_pci_mmio_write);

/* mmu depending weak syscall entries */
cond_syscall(sys_mprotect);
cond_syscall(sys_msync);
cond_syscall(sys_mlock);
cond_syscall(sys_munlock);
cond_syscall(sys_mlockall);
cond_syscall(sys_munlockall);
cond_syscall(sys_mincore);
cond_syscall(sys_madvise);
cond_syscall(sys_mremap);
cond_syscall(sys_remap_file_pages);
cond_syscall(compat_sys_move_pages);
cond_syscall(compat_sys_migrate_pages);

/* block-layer dependent */
cond_syscall(sys_bdflush);
cond_syscall(sys_ioprio_set);
cond_syscall(sys_ioprio_get);

/* New file descriptors */
cond_syscall(sys_signalfd);
cond_syscall(sys_signalfd4);
cond_syscall(compat_sys_signalfd);
cond_syscall(compat_sys_signalfd4);
cond_syscall(sys_timerfd_create);
cond_syscall(sys_timerfd_settime);
cond_syscall(sys_timerfd_gettime);
cond_syscall(compat_sys_timerfd_settime);
cond_syscall(compat_sys_timerfd_gettime);
cond_syscall(sys_eventfd);
cond_syscall(sys_eventfd2);
cond_syscall(sys_memfd_create);

/* performance counters: */
cond_syscall(sys_perf_event_open);

/* fanotify! */
cond_syscall(sys_fanotify_init);
cond_syscall(sys_fanotify_mark);
cond_syscall(compat_sys_fanotify_mark);

/* open by handle */
cond_syscall(sys_name_to_handle_at);
cond_syscall(sys_open_by_handle_at);
cond_syscall(compat_sys_open_by_handle_at);

/* compare kernel pointers */
cond_syscall(sys_kcmp);

/* operate on Secure Computing state */
cond_syscall(sys_seccomp);

/* access BPF programs and maps */
cond_syscall(sys_bpf);

/* execveat */
cond_syscall(sys_execveat);