From owner-freebsd-toolchain@freebsd.org Sat May 6 01:11:14 2017 Return-Path: Delivered-To: freebsd-toolchain@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 52A9CD5D34E for ; Sat, 6 May 2017 01:11:14 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-78.reflexion.net [208.70.210.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 03D26ADC for ; Sat, 6 May 2017 01:11:13 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 3945 invoked from network); 6 May 2017 01:11:12 -0000 Received: from unknown (HELO mail-cs-01.app.dca.reflexion.local) (10.81.19.1) by 0 (rfx-qmail) with SMTP; 6 May 2017 01:11:12 -0000 Received: by mail-cs-01.app.dca.reflexion.local (Reflexion email security v8.40.0) with SMTP; Fri, 05 May 2017 21:11:12 -0400 (EDT) Received: (qmail 20507 invoked from network); 6 May 2017 01:11:12 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 6 May 2017 01:11:12 -0000 Received: from [192.168.1.106] (c-76-115-7-162.hsd1.or.comcast.net [76.115.7.162]) by iron2.pdx.net (Postfix) with ESMTPSA id A4878EC885D; Fri, 5 May 2017 18:11:11 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) Subject: Re: llvm FreeBSD powerpc ABI target bug fix: Re: [Bug 26519] Clang 4.0.0's "Target: powerpc-unknown-freebsd11.0" code generation is violating the SVR4 ABI (SEGV can result) From: Mark Millard In-Reply-To: <78CD5050-2B2B-4213-AF11-7EF744F608B2@dsl-only.net> Date: Fri, 5 May 2017 18:11:11 -0700 Cc: FreeBSD PowerPC ML , FreeBSD Toolchain Content-Transfer-Encoding: quoted-printable Message-Id: References: <0103401A-CEEA-4992-A45E-E60EA151119B@dsl-only.net> <893ECA11-7C80-4D24-A496-92ADC7978A07@FreeBSD.org> <8F708AD1-055E-41BD-BD92-6A87C5FBAA60@dsl-only.net> <78CD5050-2B2B-4213-AF11-7EF744F608B2@dsl-only.net> To: Dimitry Andric X-Mailer: Apple Mail (2.3273) X-BeenThere: freebsd-toolchain@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Maintenance of FreeBSD's integrated toolchain List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 May 2017 01:11:14 -0000 On 2017-May-5, at 1:22 AM, Mark Millard wrote: > On 2017-May-5, at 12:45 AM, Mark Millard = wrote: >=20 >> On 2017-May-4, at 2:41 PM, Dimitry Andric wrote: >>=20 >>> . . . >>> Thanks for the notice. I have merged the upstream fix into head in >>> r317810, and I will MFC it after a few days. >>=20 >> I now have an old PowerMac running: >>=20 >> # uname -paKU >> FreeBSD FBSDG4S 12.0-CURRENT FreeBSD 12.0-CURRENT r317820M powerpc = powerpc 1200030 1200030 >>=20 >> where buildworld was via clang 4 (an amd64->powerpc >> cross build). Even the classic tiny program that >> previously showed C++ exception handling was broken >> and would crash the program now works when >> re-compiled and re-linked. Commands that were >> previous broken now work. I messed up and accidentally installed the gcc 4.2.1 world that I had also built. This is why C++ exceptions appeared to be working for powerpc. Both TARGET_ARCH=3Dpowerpc and TARGET_ARCH=3Dpowerpc64 have C++ exceptions still messed up. >> (But my testing is nearly minimal at this point.) >>=20 >> The kernel is from gcc421. >>=20 >>=20 >>=20 >> I did try booting a kernel built by system-clang 4 >> and it got to: >>=20 >> exec /sbin/init: error 13 >>=20 >> and a later alignment exception at sf_buf_alloc+0x260 >>=20 >> (Hand transcribed screen information.) >>=20 >> This is the same as the last time that I tried >> such. The exception involved: >>=20 >> exec_map_first_page >> kern_execve >> sys_execve >> start_init >> fork_exit >> fork_trampoline >>=20 >>=20 >>=20 >> For the gcc 4.2.1 based kernel boot I have >> had one odd fatal kernel trap (0x903a64a, >> "unknown") where the lr showed 0x907f . It >> reported being stopped at: >>=20 >> ffs_truncate+0x1080 >>=20 >> It appears that "call doadump" worked but >> I've not looked at what was put in >> /var/crash/ . >=20 > If I leave the PowerMac idle running: >=20 > # uname -paKU > FreeBSD FBSDG4S 12.0-CURRENT FreeBSD 12.0-CURRENT r317820M powerpc = powerpc 1200030 1200030 >=20 > it eventually gets the same ffs_truncate-tied fatal > kernel trap, with the same odd lr and the like. >=20 > So, while I cannot directly cause the problem > at a specific time, the problem is repeatable. >=20 > I did not build the kernel with a so-called > "red-zone" to work around any stack-operation > ordering problems that might still be around. > But I do not know that such is involved here. > It may be a while before I manage to get that > much of an analysis done. The ffs_truncate issue is odd: A) It was gcc 4.2.1 based for both kernel and world. B) I built a gcc 4.2.1 based debug kernel and installed it but that does not get the problem. I sam trying the gcc 4.2.1 debug kernel with the system clang 4 world now and will later switch to the gcc 4.2.1 non-debug kernel to see what happens. But being a pure gcc 4.2.1 environment originally suggests that the ffs_truncate issue is not clang-toolchain related. =3D=3D=3D Mark Millard markmi at dsl-only.net