Re: [RFC 3/3] kexec: extend kexec_file_load system call

From	Dave Young <dyoung@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [RFC 3/3] kexec: extend kexec_file_load system call
Date	2016-07-18 04:40 +0200
Message-ID	<rW6Dn-jV-9@gated-at.bofh.it> (permalink)
References	<rTUQ1-6xe-5@gated-at.bofh.it> <rTUQ2-6xe-19@gated-at.bofh.it> <rVbc6-7mF-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On 07/15/16 at 09:09am, 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.

It will not break existing programs because we can use the new param only
when the new flag is set.

But we have a case below, but I think it is fine?
Originally kexec_file_load with the new flags will fail, but now it will
succeed and will access the new argument.

Thanks
Dave

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[RFC 3/3] kexec: extend kexec_file_load system call AKASHI Takahiro <takahiro.akashi@linaro.org> - 2016-07-12 03:40 +0200
  Re: [RFC 3/3] kexec: extend kexec_file_load system call Vivek Goyal <vgoyal@redhat.com> - 2016-07-15 15:20 +0200
    Re: [RFC 3/3] kexec: extend kexec_file_load system call Mark Rutland <mark.rutland@arm.com> - 2016-07-15 15:30 +0200
      Re: [RFC 3/3] kexec: extend kexec_file_load system call Dave Young <dyoung@redhat.com> - 2016-07-18 04:40 +0200
        Re: [RFC 3/3] kexec: extend kexec_file_load system call Mark Rutland <mark.rutland@arm.com> - 2016-07-18 12:10 +0200
          Re: [RFC 3/3] kexec: extend kexec_file_load system call Dave Young <dyoung@redhat.com> - 2016-07-19 03:00 +0200
            Re: [RFC 3/3] kexec: extend kexec_file_load system call Mark Rutland <mark.rutland@arm.com> - 2016-07-19 13:00 +0200
              Re: [RFC 3/3] kexec: extend kexec_file_load system call Vivek Goyal <vgoyal@redhat.com> - 2016-07-19 14:30 +0200
                Re: [RFC 3/3] kexec: extend kexec_file_load system call Mark Rutland <mark.rutland@arm.com> - 2016-07-19 14:50 +0200
                Re: [RFC 3/3] kexec: extend kexec_file_load system call Vivek Goyal <vgoyal@redhat.com> - 2016-07-19 15:30 +0200
        RE: [RFC 3/3] kexec: extend kexec_file_load system call David Laight <David.Laight@ACULAB.COM> - 2016-07-20 13:50 +0200
          Re: [RFC 3/3] kexec: extend kexec_file_load system call Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-07-21 11:30 +0200
    Re: [RFC 3/3] kexec: extend kexec_file_load system call Dave Young <dyoung@redhat.com> - 2016-07-18 04:40 +0200

csiph-web