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=-19.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 E9D59C169C4 for ; Tue, 29 Jan 2019 19:10:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1C3C20880 for ; Tue, 29 Jan 2019 19:10:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="uZxqAvMG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729425AbfA2TKn (ORCPT ); Tue, 29 Jan 2019 14:10:43 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:34631 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727402AbfA2TKn (ORCPT ); Tue, 29 Jan 2019 14:10:43 -0500 Received: by mail-pf1-f196.google.com with SMTP id h3so10126750pfg.1 for ; Tue, 29 Jan 2019 11:10:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rxU847aHR7T2c6M//zdkC2CwszKaMbG6GQ+aqQF2dzA=; b=uZxqAvMGC8oULAByjX0cwFaArGfrNRlgVSA0PLO9RYsLPucF4hSRg78LyrpgclcdyH 2b3A8vsStSq+421IqarusuaEA3+axOEtw+P1jWbcI0pFDKapUiFU4yBwMdbeV7oSNWjH Um0HZT5tUJuzN5ttVVKw2T1lDCJSbbBIaLDn/8Os76QVeN6TzEtBwsgey+P+oYVCToMu WYO3klMFw+My3tzU5XYVRSoXPsHig5UsGcrKI22O64GWcq6lyHjDGdsIXfPWyh6RNRBR jkZ1Gwjp13BuEnJw07/Mc/Gt+bDQOJ3M4pG/hhBkSkPZAdOM815ApwCeC9xBXRhMwvjm S51A== 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:cc; bh=rxU847aHR7T2c6M//zdkC2CwszKaMbG6GQ+aqQF2dzA=; b=kXPDk/m2Ves/CKJ/0VjEepeR+fWwfcouksQeZ5jPN5zdp7tAJIbHNJk2VL+VrVGtCH k39NpojoSd/WG50BdRnixHVfar/LA/8UhYKpseQAa7B8bfJ7xWPCbRE1Mn2N8Icxq5JT ewXAHV4kI8+lMrNnDHCxWXXJiuo0WB688e/WYTria3Si+j8l+M+rxWP1s6xsltm7cz38 vKf0jHr1RfRRjrX5m999W2WxxMjo+xDzvA9Rm1o3J+Nv9pFdHA4FbiOXcx48LD9h7xbB /QIxD9asLo9RHEoLmC+KaHtGZOElMjrBCnwZWfAQbPbvYy8DAMKyzHNbWjC/ICnpO4Js nTnQ== X-Gm-Message-State: AJcUukehfzVuXURs7lTEmSjVs07LEwa9G+hUuIkvEGWaFTLZrWEwstfS vPzzPX6KF87tepxanB3daaOe1YqdFoFucRzaIvp3ag== X-Google-Smtp-Source: ALg8bN5hjm3d/AIOt3UtbIb7EhAPn78lmnQO7AhNyq+os2tY8n1mHgVmdWgSTArmyTyLJ64Q6MeyAJ6h1597vxnikEE= X-Received: by 2002:a62:b80a:: with SMTP id p10mr27269424pfe.32.1548789041503; Tue, 29 Jan 2019 11:10:41 -0800 (PST) MIME-Version: 1.0 References: <20190125005304.183322-1-ndesaulniers@google.com> <04bc6844-2a3b-2de8-60a7-a027149709fd@amd.com> <20190129185601.GA17525@roeck-us.net> In-Reply-To: From: Nick Desaulniers Date: Tue, 29 Jan 2019 11:10:30 -0800 Message-ID: Subject: Re: [PATCH] drm/amd/display: add -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines To: "Wentland, Harry" Cc: Guenter Roeck , Alex Deucher , "airlied@linux.ie" , "daniel@ffwll.ch" , "S@google.com" , "Laktyushkin, Dmytro" , "Zhou, David(ChunMing)" , "Li, Sun peng (Leo)" , "dri-devel@lists.freedesktop.org" , "Daenzer, Michel" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , "S, Shirish" , Matthias Kaehlcke , Matthias Kaehlcke , "amd-gfx@lists.freedesktop.org" , James Y Knight , "Deucher, Alexander" , Nathan Chancellor , "Cheng, Tony" , "Koenig, Christian" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Suggestions: 1. revert patch 2. get me the disassembly from gcc of the translation unit in question. 3. land patch that adds clang guards or something different based on 2. Revert first; ask questions later. On Tue, Jan 29, 2019 at 11:01 AM Wentland, Harry wrote: > > On 2019-01-29 1:56 p.m., Guenter Roeck wrote: > > On Tue, Jan 29, 2019 at 10:30:31AM -0500, Alex Deucher wrote: > >> On Fri, Jan 25, 2019 at 10:29 AM Wentland, Harry wrote: > >>> > >>> On 2019-01-24 7:52 p.m., ndesaulniers@google.com wrote: > >>>> arch/x86/Makefile disables SSE and SSE2 for the whole kernel. The > >>>> AMDGPU drivers modified in this patch re-enable SSE but not SSE2. Turn > >>>> on SSE2 to support emitting double precision floating point instructions > >>>> rather than calls to non-existent (usually available from gcc_s or > >>>> compiler_rt) floating point helper routines. > >>>> > >>>> Link: https://gcc.gnu.org/onlinedocs/gccint/Soft-float-library-routines.html > >>>> Link: https://github.com/ClangBuiltLinux/linux/issues/327 > >>>> Cc: stable@vger.kernel.org # 4.19 > >>>> Reported-by: S, Shirish > >>>> Reported-by: Matthias Kaehlcke > >>>> Suggested-by: James Y Knight > >>>> Suggested-by: Nathan Chancellor > >>>> Signed-off-by: Nick Desaulniers > >>>> Tested-by: Guenter Roeck > >>> > >>> Reviewed-by: Harry Wentland > >>> > >>> and applied. > >>> > >> > >> This patch causes a segfault: > >> https://bugs.freedesktop.org/show_bug.cgi?id=109487 > >> > >> Any ideas? > >> > > > > Set -msse2 only for clang ? I suspect, though, that this might only > > solve the compile problem. If I understand correctly, the first > > warning in the log is due to BREAK_TO_DEBUGGER(), suggesting that > > something is seriously wrong. Maybe enabling sse2 results in different > > results from floating point operations. > > > > Unfortunately I don't have a system with the affected GPU, > > so I can't run any tests on real hardware. Unless someone can test > > with real hardware, I think we have no choice but to revert the > > patch. > > > > Might be a good idea. Even though, best to revert for now until we understand what's going on. > > It seems like people at AMD building with gcc 5.4 are fine, but those using gcc 7.3 or 8.2 experience the crash. > > Harry > > > Guenter > > > >> Alex > >> > >>> Harry > >>> > >>>> --- > >>>> drivers/gpu/drm/amd/display/dc/calcs/Makefile | 2 +- > >>>> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +- > >>>> 2 files changed, 2 insertions(+), 2 deletions(-) > >>>> > >>>> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile > >>>> index 95f332ee3e7e..dc85a3c088af 100644 > >>>> --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile > >>>> +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile > >>>> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),) > >>>> cc_stack_align := -mstack-alignment=16 > >>>> endif > >>>> > >>>> -calcs_ccflags := -mhard-float -msse $(cc_stack_align) > >>>> +calcs_ccflags := -mhard-float -msse -msse2 $(cc_stack_align) > >>>> > >>>> CFLAGS_dcn_calcs.o := $(calcs_ccflags) > >>>> CFLAGS_dcn_calc_auto.o := $(calcs_ccflags) > >>>> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile > >>>> index d97ca6528f9d..33c7d7588712 100644 > >>>> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile > >>>> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile > >>>> @@ -30,7 +30,7 @@ else ifneq ($(call cc-option, -mstack-alignment=16),) > >>>> cc_stack_align := -mstack-alignment=16 > >>>> endif > >>>> > >>>> -dml_ccflags := -mhard-float -msse $(cc_stack_align) > >>>> +dml_ccflags := -mhard-float -msse -msse2 $(cc_stack_align) > >>>> > >>>> CFLAGS_display_mode_lib.o := $(dml_ccflags) > >>>> CFLAGS_display_pipe_clocks.o := $(dml_ccflags) > >>>> > >>> _______________________________________________ > >>> amd-gfx mailing list > >>> amd-gfx@lists.freedesktop.org > >>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx -- Thanks, ~Nick Desaulniers