From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 333D0C32751 for ; Sat, 10 Aug 2019 22:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 016C620880 for ; Sat, 10 Aug 2019 22:51:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726427AbfHJWvX (ORCPT ); Sat, 10 Aug 2019 18:51:23 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:33531 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726014AbfHJWvW (ORCPT ); Sat, 10 Aug 2019 18:51:22 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 465cm81cblz9sN1; Sun, 11 Aug 2019 08:51:19 +1000 (AEST) From: Michael Ellerman To: Linus Torvalds Cc: Linux List Kernel Mailing , linuxppc-dev@lists.ozlabs.org Cc: segher@kernel.crashing.org, arnd@arndb.de, Nick Desaulniers , Nathan Chancellor , clang-built-linux@googlegroups.com, Christophe Leroy Subject: Re: [GIT PULL] Please pull powerpc/linux.git powerpc-5.3-4 tag In-Reply-To: References: <87imr5s522.fsf@concordia.ellerman.id.au> Date: Sun, 11 Aug 2019 08:51:19 +1000 Message-ID: <87ftm8skgo.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ expanded Cc ] Linus Torvalds writes: > On Sat, Aug 10, 2019 at 3:11 AM Michael Ellerman wrote: >> >> Just one fix, a revert of a commit that was meant to be a minor improvement to >> some inline asm, but ended up having no real benefit with GCC and broke booting >> 32-bit machines when using Clang. > > Pulled, but whenever there are possible subtle compiler issues I get > nervous, and wonder if the problem was reported to the clang guys? Yes, sorry I should have included more context. It was actually the Clang Linux folks who noticed it and reported it to us: https://github.com/ClangBuiltLinux/linux/issues/593 There's an LLVM bug filed: https://bugs.llvm.org/show_bug.cgi?id=42762 And I think there's now agreement that the Clang behaviour is not correct, Nick actually sent a revert as well but I already had one queued: https://patchwork.ozlabs.org/patch/1144980/ Arnd identified some work arounds, which we may end up using, but for this cycle we thought it was preferable to just revert this change as it didn't actually change code generation with GCC anyway. cheers