From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by lists.ozlabs.org (Postfix) with ESMTP id 3rrY8R1xnGzDqF6 for ; Fri, 15 Jul 2016 23:20:06 +1000 (AEST) Date: Fri, 15 Jul 2016 14:19:51 +0100 From: Mark Rutland To: Vivek Goyal Cc: AKASHI Takahiro , bhe@redhat.com, arnd@arndb.de, linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, ebiederm@xmission.com, bauerman@linux.vnet.ibm.com, dyoung@redhat.com, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC 3/3] kexec: extend kexec_file_load system call Message-ID: <20160715131950.GB19840@leverpostej> References: <20160712014201.11456-1-takahiro.akashi@linaro.org> <20160712014201.11456-4-takahiro.akashi@linaro.org> <20160715130955.GC23514@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160715130955.GC23514@redhat.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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. Thanks, Mark.