From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752152AbcAFUV0 (ORCPT ); Wed, 6 Jan 2016 15:21:26 -0500 Received: from mail-oi0-f46.google.com ([209.85.218.46]:35303 "EHLO mail-oi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751959AbcAFUVW (ORCPT ); Wed, 6 Jan 2016 15:21:22 -0500 Subject: Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb To: Peter Zijlstra References: <1451572003-2440-1-git-send-email-mst@redhat.com> <1451572003-2440-32-git-send-email-mst@redhat.com> <20160105232735.GC238@brightrain.aerifal.cx> <20160106131321-mutt-send-email-mst@redhat.com> <20160106114023.GU6344@twins.programming.kicks-ass.net> <20160106134301-mutt-send-email-mst@redhat.com> <20160106143218.GV6344@twins.programming.kicks-ass.net> <568D35EB.7090108@landley.net> <20160106165740.GX6344@twins.programming.kicks-ass.net> Cc: "Michael S. Tsirkin" , Rich Felker , linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, Jeff Dionne , Yoshinori Sato From: Rob Landley Message-ID: <568D773F.6000408@landley.net> Date: Wed, 6 Jan 2016 14:21:19 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20160106165740.GX6344@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06/2016 10:57 AM, Peter Zijlstra wrote: > On Wed, Jan 06, 2016 at 09:42:35AM -0600, Rob Landley wrote: >> (I would have thought the presence of working QEMU support would tide us >> over providing an easy basic regression testing environment, but people >> keep insisting that's not real and doesn't count. But if we can keep it >> 99% working until the sh4 patents expire later this year, we can add mmu >> and have full sh4 in hardware again with BSD VHDL.) > > I didn't know there was a 'working' qemu for SH. Yes, for several years now? https://lists.gnu.org/archive/html/qemu-devel/2010-03/msg00976.html I try to build bootable images with each new kernel, although I'm a few versions behind at the moment (this is 4.1 I think?): wget http://landley.net/aboriginal/bin/system-image-sh4.tar.gz tar xvzf system-image-sh4.tar.gz cd system-image-sh4 ./run-emulator.sh There's an sh2eb one in there too, but you need a $50 FPGA board to run it (Numato Mimas v2, setup walkthrough is at http://nommu.org/jcore). I keep meaning to poke at qemu and get their r2d board emulation to give me more than 64 megs of memory so I can do native compiles. (I have a native toolchain but building much more than "hello world" requires setting up a swap file because the board emulation only gives me one virtual disk. None of the other architectures need that...) I'd _also_ like to get proper sh2 support into qemu (sh2 code runs under sh4 but still), but the sh4 patents expire later this year and sometime after that we want to add an MMU to the VHDL, so... (We still want the nommu version because hard realtime is actually easier to verify without page faults, and the big product needs nanosecond accurate timestamps on stuff...) > My personal 'complaint' with SH is its lack of maintainer feedback. I do > full arch sweeps on semi-regular basis, and while I know in very board > terms how a fair number of archs work its impossible to know everything > about all 25+ we support. We (the j-core guys) have wanted to take over arch/sh maintainership for a while, we've just been trying to get the board we're working on in position to be upstreamed first. The feedback on my craptacular first effort to chip off a chunk that other people could at least reproduce against a then-current kernel was "ew" and "redo it all as device tree". So we went away again to work on that... Meanwhile all $DAYJOB's in-house resources (at se-instruments.com) have been tied up making SMP work for a product. (Yes, sh2 SMP. A NOMMU smp system. There were some teething troubles, but it's working now. Alas, not on the above $50 FPGA because that's only got an LX9 FPGA which one SOC instance uses like 2/3 of the gates in. We're doing the SMP stuff in LX45 boards, which are crazy expensive.) I note I just sent a Numato board to the buildroot maintainer so I can walk him through adding jcore support to buildroot. And I got toybox working nommu, and Rich added sh2 support to musl-libc... There has been activity on this arch, just not on this list due to the noise from a bunch of different Renesas arm systems and whatever "arm/shmobile" is. ("Not superh or jcore compatible", that's all I know...) Rob