adding a new linux syscall: fallocate

[r0ller <r0ller%freemail.hu@localhost>]

Hi All,

I'm trying to add a new linux syscall called fallocate just to map it to the existing posix_fallocate whenever it's possible (as it is nonportable for its mode as far as I can see). I've read some docs (but certain things may have been overlooked) like:

https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
http://man7.org/linux/man-pages/man2/fallocate.2.html
https://www.netbsd.org/docs/internals/en/chap-processes.html#syscall_howto
https://www.netbsd.org/docs/kernel/programming.html#adding_a_system_call

What I've done so far on a NetBSD-8.0 VM after pulling its source:

1) modified: /usr/src/sys/compat/linux/arch/amd64/syscalls.master like:
285 STD { int|linux_sys||fallocate(int fd, int mode, linux_off_t offset, linux_off_t len); }

2) added linux_sys_fallocate() to /usr/src/sys/compat/linux/common/linux_file.c like:
int linux_sys_fallocate(int fd, int mode, linux_off_t offset, linux_off_t len){
    printf("Calling linux_sys_fallocate\n");
    return EOPNOTSUPP;
}

Question: is that the right place to add linux_sys_fallocate()?

3) issued make in /usr/src/sys/compat/linux/arch/amd64 which seems to have done its job right but do I need to do so as well in /usr/src/sys/compat/linux??? If I do so I get:
don't know how to make syscalls.master. Stop.

4) rebuilt the GENERIC kernel which stopped when it got to linux_file.o. The error message didn't say anything more only that it stopped there but judging by that compiling linux_file.c went fine but linking failed.

Thanks for any hints!

Best regards,
r0ller