On 07/15/16 at 02:19pm, Mark Rutland wrote: > On Fri, Jul 15, 2016 at 09:09:55AM -0400, Vivek Goyal wrote: > > On Tue, Jul 12, 2016 at 10:42:01AM +0900, AKASHI Takahiro wrote: > > > > [..] > > > -SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, > > > +SYSCALL_DEFINE6(kexec_file_load, int, kernel_fd, int, initrd_fd, > > > unsigned long, cmdline_len, const char __user *, cmdline_ptr, > > > - unsigned long, flags) > > > + unsigned long, flags, const struct kexec_fdset __user *, ufdset) > > > > Can one add more parameters to existing syscall. Can it break existing > > programs with new kernel? I was of the impression that one can't do that. > > But may be I am missing something. > > I think the idea was that we would only look at the new params if a new > flags was set, and otherwise it would behave as the old syscall. > > Regardless, I think it makes far more sense to add a kexec_file_load2 > syscall if we're going to modify the prototype at all. It's a rather > different proposition to the existing syscall, and needs to be treated > as such. I do not think it is worth to add another syscall for extra fds. We have open(2) as an example for different numbers of arguments already. Thanks Dave
