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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 37889C433DF for ; Sat, 10 Oct 2020 00:12:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA05222251 for ; Sat, 10 Oct 2020 00:12:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="mijmHtCM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728621AbgJJALW (ORCPT ); Fri, 9 Oct 2020 20:11:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728618AbgJJABF (ORCPT ); Fri, 9 Oct 2020 20:01:05 -0400 Received: from mail-ed1-x542.google.com (mail-ed1-x542.google.com [IPv6:2a00:1450:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F088CC0613D6 for ; Fri, 9 Oct 2020 17:01:03 -0700 (PDT) Received: by mail-ed1-x542.google.com with SMTP id l16so11170110eds.3 for ; Fri, 09 Oct 2020 17:01:03 -0700 (PDT) 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=NyEG6unrPY9TR7tF+FNQAaLApT1kctBGIfqP3l5IFb4=; b=mijmHtCMvGsgDu4uYd7w3AkGuavHKsRtISq1sPYHXYFaJw1WU+TYM2fX64XYscUKFv oU1cjxRYTJM1zp/QWqADJjTuB9hPhK+ZKhKINQnaiff6eqCzhX5w5wrxbRlGrJ0vyWiv ro3O+Z6DBIysL9dvjFawfl9YpJ7VnqXVeFq0auogXHWgzG/yIY2Ex8Vg0F1RLU4QxqSG bPLvghG+BsOIiRJ7zUxm1IgTps9IY/HH1VRZFA09lds3Gl17NZfWxvoZiUPcmFwlV7So V3Y3SV5Dt+Y35HFON8xSJwLyPjVkAmtWcAvVa4XffcGawnjsCdKwV9RsaQRB1eOPndHI e4Ew== 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=NyEG6unrPY9TR7tF+FNQAaLApT1kctBGIfqP3l5IFb4=; b=XVyvZ/tyEz23/bd1Do4OBUr6YObsxRXbATDK+hyJ2Nrc30AbTf8fSlYmrm4MGFfwsB wGBv2JOIBXdYtOkxx2ulJz20VmL5+1W2pfAWqbWiBSRQD+oCQsKu3mlp376bb5Nwp0bE NNOzenj0oLnFv69xmt6MYe3koURoQlugV8Rd/4Z22O8vJWwqOu3zyRvp5zwj2t4ZE6nx cc7C1deP7UW4RI15cXNVt0nRmivJyxnPj46HW2vkXH2IZsE6c4WXGKrADBWLDirdwjhM VtJtHwhKHL2eRJvVBzwX50lIeQdJj+ZUsf+klIJ//ijtNOMEsIMO8jgAfCcU8dhBQpzM Wazw== X-Gm-Message-State: AOAM532gQc3/xWRQAAKcfP5tXUGLZ63ps23ymTYN7vCD7o4ModDNp3Bc PFfn6dvseIObuw3lArrbjyq9j++udaJ83pDybOXS+A== X-Google-Smtp-Source: ABdhPJygCrm7pkL/BYEq335cylOsmwx8yyljt1uWu6UwT8l62xqSHabdTtXkuhnBI7dZHTHKXqo8112Hls6msX6/ovk= X-Received: by 2002:a50:dec9:: with SMTP id d9mr1852468edl.145.1602288062227; Fri, 09 Oct 2020 17:01:02 -0700 (PDT) MIME-Version: 1.0 References: <20201009161338.657380-1-samitolvanen@google.com> <20201009153512.1546446a@gandalf.local.home> <20201009210548.GB1448445@google.com> <20201009193759.13043836@oasis.local.home> In-Reply-To: <20201009193759.13043836@oasis.local.home> From: Sami Tolvanen Date: Fri, 9 Oct 2020 17:00:51 -0700 Message-ID: Subject: Re: [PATCH v5 00/29] Add support for Clang LTO To: Steven Rostedt Cc: Masahiro Yamada , Will Deacon , Peter Zijlstra , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux , Kernel Hardening , linux-arch , linux-arm-kernel , linux-kbuild , LKML , linux-pci@vger.kernel.org, X86 ML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On Fri, Oct 9, 2020 at 4:38 PM Steven Rostedt wrote: > > On Fri, 9 Oct 2020 14:05:48 -0700 > Sami Tolvanen wrote: > > > Ah yes, X86_DECODER_SELFTEST seems to be broken in tip/master. If you > > prefer, I have these patches on top of mainline here: > > > > https://github.com/samitolvanen/linux/tree/clang-lto > > > > Testing your config with LTO on this tree, it does build and boot for > > me, although I saw a couple of new objtool warnings, and with LLVM=1, > > one warning from llvm-objdump. > > Thanks, I disabled X86_DECODER_SELFTEST and it now builds. > > I forced the objdump mcount logic with the below patch, which produces: > > CONFIG_FTRACE_MCOUNT_RECORD=y > CONFIG_FTRACE_MCOUNT_USE_OBJTOOL=y > > But I don't see the __mcount_loc sections being created. > > I applied patches 1 - 6. Patch 6 is missing the part where we actually pass --mcount to objtool, it's in patch 11 ("kbuild: lto: postpone objtool"). I'll fix this in v6. In the meanwhile, please apply patches 1-11 to test the objtool change. Do you have any thoughts about the approach otherwise? Sami