From owner-freebsd-current@freebsd.org Fri Mar 1 13:14:08 2019 Return-Path: Delivered-To: freebsd-current@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 EC84A1517145 for ; Fri, 1 Mar 2019 13:14:07 +0000 (UTC) (envelope-from freebsd-rwg@pdx.rh.CN85.dnsmgr.net) Received: from pdx.rh.CN85.dnsmgr.net (br1.CN84in.dnsmgr.net [69.59.192.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E88D18022A; Fri, 1 Mar 2019 13:14:06 +0000 (UTC) (envelope-from freebsd-rwg@pdx.rh.CN85.dnsmgr.net) Received: from pdx.rh.CN85.dnsmgr.net (localhost [127.0.0.1]) by pdx.rh.CN85.dnsmgr.net (8.13.3/8.13.3) with ESMTP id x21DE2mL061465; Fri, 1 Mar 2019 05:14:02 -0800 (PST) (envelope-from freebsd-rwg@pdx.rh.CN85.dnsmgr.net) Received: (from freebsd-rwg@localhost) by pdx.rh.CN85.dnsmgr.net (8.13.3/8.13.3/Submit) id x21DE2OB061464; Fri, 1 Mar 2019 05:14:02 -0800 (PST) (envelope-from freebsd-rwg) From: "Rodney W. Grimes" Message-Id: <201903011314.x21DE2OB061464@pdx.rh.CN85.dnsmgr.net> Subject: Re: r343567 aka PAE vs non-PAE merge breaks i386 freebsd In-Reply-To: To: Warner Losh Date: Fri, 1 Mar 2019 05:14:02 -0800 (PST) CC: John Baldwin , Cy Schubert , "Conrad E. Meyer" , Steve Kargl , freebsd-current X-Mailer: ELM [version 2.4ME+ PL121h (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: E88D18022A X-Spamd-Bar: + Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [1.96 / 15.00]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; NEURAL_SPAM_SHORT(0.50)[0.498,0]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[dnsmgr.net]; AUTH_NA(1.00)[]; RCPT_COUNT_FIVE(0.00)[6]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; MX_GOOD(-0.01)[cached: pdx.rh.CN85.dnsmgr.net]; NEURAL_SPAM_LONG(0.13)[0.133,0]; NEURAL_SPAM_MEDIUM(0.43)[0.431,0]; R_SPF_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:13868, ipnet:69.59.192.0/19, country:US]; MID_RHS_MATCH_FROM(0.00)[]; IP_SCORE(0.01)[ip: (0.06), ipnet: 69.59.192.0/19(0.03), asn: 13868(0.01), country: US(-0.07)] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Mar 2019 13:14:08 -0000 > On Thu, Feb 28, 2019 at 12:46 PM John Baldwin wrote: > > > On 2/28/19 11:14 AM, Cy Schubert wrote: > > > On February 28, 2019 11:06:46 AM PST, Conrad Meyer > > wrote: > > >> On Thu, Feb 28, 2019 at 10:32 AM Steve Kargl > > >> wrote: > > >>> This is interesting as well. Does this mean that amd64 is now > > >>> the only tier 1 platform and all other architectures are after > > >>> thoughts? > > >> > > >> This has been the de facto truth for years. i386 is mostly only > > >> supported by virtue of sharing code with amd64. There are efforts to > > >> promote arm64 to Tier 1, but it isn't there yet. Power8+ might be > > >> another good alternative Tier 1 candidate eventually. None have > > >> anything like the developer popularity that amd64 enjoys. > > >> > > >> Conrad > > >> _______________________________________________ > > >> freebsd-current@freebsd.org mailing list > > >> https://lists.freebsd.org/mailman/listinfo/freebsd-current > > >> To unsubscribe, send any mail to > > >> "freebsd-current-unsubscribe@freebsd.org" > > > > > > We deprecated and removed support for 386 and 486 processors. We should > > consider removing support for low end Pentium as well. I'm specifically > > thinking of removing the workarounds like F00F. Are there any processors > > that are still vulnerable to this? > > > > We have only removed support for 386 since it didn't support cmpxchg. We > > still > > nominally support 486s. I don't know how well FreeBSD 13 would run on a > > 486, but > > in theory the code is still there and the binaries shouldn't die with > > illegal > > instruction faults. > > > > The biggest barrier to running on a real 486 is that it's hard for FreeBSD > to fit into 32MB that was the maximum config you could have. You can barely > boot it w/o tuning, though it will still fit a few jobs if you are looking > at something super low-end with a lot of effort. Effort that has been completed in several places, wifi-build for one, where I did boot a 12.0 image of 8MB in size running in 32MB iirc on a D-Link DIR-855? router. > There are a few later CPUs built on basically a 486 whose chipsets could > support up to 128MB or 256MB which is enough to run FreeBSD still. Amd Geode would be in that group? -- Rod Grimes rgrimes@freebsd.org