From owner-freebsd-mips@freebsd.org Wed Dec 12 22:15:32 2018 Return-Path: Delivered-To: freebsd-mips@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6EDCF132828B for ; Wed, 12 Dec 2018 22:15:32 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id AE05084A75 for ; Wed, 12 Dec 2018 22:15:31 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-qk1-x72e.google.com with SMTP id 68so440853qke.9 for ; Wed, 12 Dec 2018 14:15:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=Ti9hsbGutnra9axAWE98Cvonk9my88YDLvk1iecXs6g=; b=JfOCiUePC9i3meKqSalfmsYBS/zrJM8GEIBTcMEz+fqHFZO9MipRhGEUHo8ko6Wnp9 DWbvF4QDNArahI3Jmm8nY9LopiH+aMgNtQ5KCxfOuXJWi8tsd36X8rsN1mCXfb2q2nJL 8pVTxlmogMVBkg6Kc2JvUk5XXUg5v4WqBEIzNfelPcaqkfEchg/rc7Hb8RORVdjx0ood /tfkG2qz3pCev3VojxhAtKn7Af1bC6kZCoT5qZYTb0tlcmj3DtAGhCjWBTdIMpai/+/T DyX2I5RX2D+vcNAvwUSvLrbphERQB/L1D+0mLjA+ugoCPa3fM8F9IWWl8gyKJGoxtG++ S8CA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=Ti9hsbGutnra9axAWE98Cvonk9my88YDLvk1iecXs6g=; b=jIsJo9Q8FLu6CdglfbwAb5Iw4z+He0VKBZifeHbqr94j22ukToIVtBMhFh/Ea/4u9c PIaPyNfCBWGjfEoSuUY1sDRp0mC6N61HmOp29x6h4F10TFKlwrEeIzUexYOwagLXbUAN FUWJI77a9PS24TQiHiyfSJBHK0I9DimsoGlKsfAWgHLJSlAP5SceWGwjVhVC5w6sAmXF dag35kvlh40xerFDLYsXbal9PsOLzkDg3PzDSqcx31iCzDR1qrFQkkLr3Hn9BlamZrbJ uV0Ckhu62vavyYUakqwOpRI7GFEeK1+AfklQo78uVriNfd6BYiJ7sIVi3uBoe18cC5Wq DNlQ== X-Gm-Message-State: AA+aEWZgkiUCkihJ8Xr+dgK0B2mA1wME3cGHjYtPu1GMoyJMm8DzRJRF pJfEzswstwjGnoVjOgTMr2cQduEW3oX6NzxZrTjl0gBS X-Google-Smtp-Source: AFSGD/V8ABXD02RdJqWnNAC5cXXXpZ26VaY2Cw4qPHuG8EC0PZ2ssuCLZDhc+XPJCpFNuYxbq4QznaBPYqZFyDDoKLQ= X-Received: by 2002:a37:c653:: with SMTP id b80mr20785646qkj.245.1544652930706; Wed, 12 Dec 2018 14:15:30 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Warner Losh Date: Wed, 12 Dec 2018 15:15:19 -0700 Message-ID: Subject: Re: MIPS future... To: "freebsd-mips@freebsd.org" X-Rspamd-Queue-Id: AE05084A75 X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=bsdimp-com.20150623.gappssmtp.com header.s=20150623 header.b=JfOCiUeP X-Spamd-Result: default: False [-4.21 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.99)[-0.986,0]; R_DKIM_ALLOW(-0.20)[bsdimp-com.20150623.gappssmtp.com:s=20150623]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-mips@freebsd.org]; DMARC_NA(0.00)[bsdimp.com]; RCPT_COUNT_ONE(0.00)[1]; IP_SCORE(-2.28)[ip: (-8.46), ipnet: 2607:f8b0::/32(-1.57), asn: 15169(-1.29), country: US(-0.09)]; MX_GOOD(-0.01)[cached: ALT1.aspmx.l.google.com]; DKIM_TRACE(0.00)[bsdimp-com.20150623.gappssmtp.com:+]; RCVD_IN_DNSWL_NONE(0.00)[e.2.7.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; NEURAL_HAM_SHORT(-0.93)[-0.935,0]; TO_DN_EQ_ADDR_ALL(0.00)[]; R_SPF_NA(0.00)[]; FORGED_SENDER(0.30)[imp@bsdimp.com,wlosh@bsdimp.com]; MIME_TRACE(0.00)[0:+,1:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FROM_NEQ_ENVFROM(0.00)[imp@bsdimp.com,wlosh@bsdimp.com]; RCVD_COUNT_TWO(0.00)[2] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: freebsd-mips@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Porting FreeBSD to MIPS List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Dec 2018 22:15:32 -0000 On Wed, Dec 12, 2018 at 11:15 AM Warner Losh wrote: > OK. To be a good player in the FreeBSD ecosystem, we need to do a few > things. > > First, we need to implement atomic_swap_64. hps did this for mips64 and > committed it. He sent me some further patches for it that I need to commit > when I get a change, maybe at the airport tonight. > > But this brings up a couple of issues I'd like to bring up. > > First, to implement atomic_swap_64 on mips-32 is hard. In that it's not > just the canonical ldd/sdd sequence because those aren't available there. > We can do the standard trick of reading STATUS0, clearing IE, storing it, > do the operation and then restoring STATUS0. This is efficient enough for > the use in the kernel for the supported cores we have. > > With two exceptions. First is running 32-bit kernels on 64-bit hardware. > We deprecated that with Octeon because of the weird hacks we needed to do > too make it work. I'd like to universally deprecate this. There's little > benefit and a real cost to doing this. I'd like to remove the SWARM_SMP, > XLP, and GXEMUL32 (or at least remove the smp option). > > But there's JZ4780. It's a legit mips32 + SMP. It's on Image Creator's > CI20. This was released in Nov 2014 with a refresh in March 2015. This is a > dead-end product line (there's no new cores and none new that I can find). > This was a RPi competitor, but it was slower, less capable and more > expensive so it's kinda rare now. I'd say we need to de-support this > device. I know of only one user, and he's not responded to my email. I > think 12 will have to be the last release we have this in. Today, the only > affect is for some drivers that can't run on this platform, but the writing > is on the wall. > > That brings me to my next question: SWARM. Can we kill SWARM entirely? > It's for the BCM1250 part, released in sometime before 2000. It was super > popular because it was the reference for a ton of things that followed. I > think it's run is over and we can remove it. I can find no users of it in > the nyc dmesg database. Mine has been in a plastic bag since before my sone > was born in 2006... So I'm thinking we can remove this platform. It was on > the edge last time I did a GC in mips-land. > > And then there's the even larger question: how many people are still using > mips32? It looks like a fair number, maybe, but I have no idea for sure, so > if you do, please provide feedback on the platforms you are running FreeBSD > 11 or newer on. > There's one last issue this brings up. When writing the above code, I discovered I could use the non-racy DI instruction. However, that was introduced with mips32r2. This was defined in 2002 and gear appeared in the market 2004 or 2005. I believe that all supported SoCs have mips32r2. SWARM doesn't, which is another reason to kill it: it's getting in the way and providing no benefit. Would anybody object to the minimum ISA being raised to mips32r2 for all 32-bit mips platforms? Warner