From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCHv2 1/2] clone: Support passing tls argument via C rather than pt_regs magic Date: Tue, 12 May 2015 23:38:43 +0200 Message-ID: <20150512213843.GV21418@twins.programming.kicks-ass.net> References: <20150511192918.GA11361@jtriplet-mobl1> <20150512142250.dcb053da81855ae1b5861173@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20150512142250.dcb053da81855ae1b5861173@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org To: Andrew Morton Cc: Josh Triplett , Andy Lutomirski , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Linus Torvalds , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org List-Id: linux-api@vger.kernel.org On Tue, May 12, 2015 at 02:22:50PM -0700, Andrew Morton wrote: > On Mon, 11 May 2015 12:29:19 -0700 Josh Triplett wrote: > > > Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt > > into, and a new copy_thread_tls that accepts the tls parameter as an > > additional unsigned long (syscall-argument-sized) argument. > > Change sys_clone's tls argument to an unsigned long (which does > > not change the ABI), and pass that down to copy_thread_tls. > > > > Architectures that don't opt into copy_thread_tls will continue to > > ignore the C argument to sys_clone in favor of the pt_regs captured at > > kernel entry, and thus will be unable to introduce new versions of the > > clone syscall. > > What happens quite frequently is that we do something for x86 with the > expectation that other architectures will follow along, but this > doesn't happen. The arch maintainers simply didn't know about it or > nobody nags them. Nothing happens and inconsistencies hang around for > years. eg, http://lkml.iu.edu/hypermail/linux/kernel/1504.2/04993.html > > I'm thinking we should find a way to do this better. One way might be > to maintain a Documentation/arch-todo which identifies each item, has a > little list of what-to-do instructions and perhaps a list of the > not-yet-done architectures. Basically a way for everyone to > communicate at the arch maintainers. If only there was a linux-arch list to which arch maintainers should subscribe... oh wait :-)