From owner-freebsd-mips@freebsd.org Thu Jan 11 03:10:27 2018 Return-Path: Delivered-To: freebsd-mips@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id F19DFE668D0 for ; Thu, 11 Jan 2018 03:10:26 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-wm0-x22f.google.com (mail-wm0-x22f.google.com [IPv6:2a00:1450:400c:c09::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49B007B436 for ; Thu, 11 Jan 2018 03:10:26 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-wm0-x22f.google.com with SMTP id x4so736126wmc.0 for ; Wed, 10 Jan 2018 19:10:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=1wlH4/Vup2EnfFKVIafHmnSX99suCcj3F6s75hs+tCA=; b=FCrEVn4I/UsC0E/iKONlM9Smj6PtB7VyFVAlvNEu9wLAGp7HPX3w+dNfFNfU+0zIBG 1XgZLWzN4odpO43Ia5fpuvK/fVvBhKM+mBzKJYCJ3hBD7XNNYHh20ruXfJMOOC6NPyVv fOcRFp/6HUsFNmv3boNE6rvW/QX9ZpU3iA/9unVzInXDDD9rkciP9a1U+TZjmSL0Dbk7 zX1WZxLZ/osVoFAVrBZaRtjGkb7uAOaEksm5Dy10QLT8ZTr8LhDygWcvboxx7Vw6OROd Tw23JfORjMF4bF+h4+U5+ZZiJ30QLQq9IZbrFD317VKo5sPM/ASuLC8ug91oQbvp43g1 a/dw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=1wlH4/Vup2EnfFKVIafHmnSX99suCcj3F6s75hs+tCA=; b=XDVcRkKUvoNuiiO+Mzq7FKUssaUwCZENTrNl3SF9dKNNY69W+PjaKJkyUhjUGD8f3H T6k175/tZU+mi/iDNuqxn+fDZhUXqjpEEHjyNQgRwqiS796+mJYJmTTzRFWI4aFOP9lD Wn3iyMNVAYMl0PJpQgjNIZC0wbyx6x59TsxjoeIWsq1dzOvkKHGr9KAK0feiVnUnlg6t uvyo716hfzZ/3GOC3h6bQVz/dyNhXPqyYmtOqaBn4IdZhHrQvnr1XpAin2WTFJ/EEwGU nkOsI4PpmF5HF5vaiBep3+4tz8mkscg8E+CVOo9ksTp+1J3pcjVcQyb62h3y1Z8XrVuC 8iyg== X-Gm-Message-State: AKGB3mJ87UXdOOf5HtqHlTAXCab9Mk/hEKkEnFkjW8GynXD+GPuDT7z+ o++n/jjIh18x7xrN+bmXCmPMpr2D4F7Q9B2fnRg0Tg== X-Google-Smtp-Source: ACJfBotWFMyojQ3m763ilrZzssXiMPjcPeWKscJTFLfIfJfNBt3KvMzsOa8b2hfzH2IQk7y6Y9b42+8gVqHTFMwOLk0= X-Received: by 10.80.186.161 with SMTP id x30mr28801844ede.138.1515640224528; Wed, 10 Jan 2018 19:10:24 -0800 (PST) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 10.80.195.88 with HTTP; Wed, 10 Jan 2018 19:10:23 -0800 (PST) X-Originating-IP: [50.253.99.174] In-Reply-To: <20180111004929.GA17499@bloaty> References: <20180111004929.GA17499@bloaty> From: Warner Losh Date: Wed, 10 Jan 2018 20:10:23 -0700 X-Google-Sender-Auth: BK2XegaVx-1y--bTcunHOgG5WLI Message-ID: Subject: Re: Switch to hard-float by default? To: Alex Zepeda Cc: "freebsd-mips@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: freebsd-mips@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Porting FreeBSD to MIPS List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Jan 2018 03:10:27 -0000 On Wed, Jan 10, 2018 at 5:49 PM, Alex Zepeda wrote: > > On Wed, Jan 10, 2018 at 12:54 PM, John Baldwin wrote: > > > > > I have been working on LLVM libunwind patches for MIPS and the last > round > > > has > > > been to teach the unwinder to handle hard-float. As part of this I > just > > > fixed > > > a bug which had broken HF support for N32 (in review now), and I have a > > > working 'mipsn32hf' world that boots under qemu. However, if I add > > > 'mipsn32hf' to the list of known targets that is yet another world to > add > > > to make universe. I wonder if instead we should consider switching > MIPS to > > > assume hard-float by default? We made that change for 32-bit arm > recently. > > > > > > The simplest approach would be to add 'mipsn32hf' and then remove all > the > > > non '*hf' targets from Makefile.inc1 (if we only wanted to support > HF). A > > > more drastic approach would be to change the existing 'mips*' targets > to > > > assume hard-float, remove all the '*hf' targets (which are only in 12 > > > anyway > > > I think?) and add in explicit '*sf' targets if anyone has a need for > them. > > > Given that none of the *hf targets have been MFC'd are only present in > 12 > > > anyway, maybe the more drastic route is actually better? If we do go > that > > > route, does anyone have a use case for a '*sf' target? That is, is > anyone > > > running FreeBSD/mips on a processor that does not include an FPA? > > > > > > > I think that I retired the last set of SoCs that only had soft float. > > > > I think this is a good idea. > > > > The only use case I can think of is if I'm wrong and some of the early > > Atheros SoCs can do soft float. But then we'd just have one supported > > soft-float platform to worry about rather than the full generality we > have > > now. > > > > Warner > > Are you sure? I'm pretty sure a lot of the 32 bit SoCs don't have FPUs > standard. I'm currently poking at a MediaTek 7621 board (EdgeRouter X) > and it doesn't have an FPU. Looking through the MediaTek documents it > looks > like FPUs are an optional accessory on many of their SoCs. > You may be right about that... I think there's a good case to be made for going the sf route here for those that need it. I can think of other alternatives, but this is the least bad one. Warner