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=-19.4 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_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 00CBFC432C1 for ; Tue, 24 Sep 2019 18:32:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEBAB207FD for ; Tue, 24 Sep 2019 18:32:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="LLxllnZj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405417AbfIXScT (ORCPT ); Tue, 24 Sep 2019 14:32:19 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:37928 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392088AbfIXScT (ORCPT ); Tue, 24 Sep 2019 14:32:19 -0400 Received: by mail-pf1-f194.google.com with SMTP id h195so1863206pfe.5 for ; Tue, 24 Sep 2019 11:32:18 -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=MFxAZD1w5UhTlzLtE5TmBr2XeUa2P0bLYhndFfGu00E=; b=LLxllnZjxLQEkI7TInx636+7EuAGGhGvR+v/4upvBsIM7hSokgnlBB57aHaRGs7QWZ PocntCahXvUaEtsgonPtApkdgyww6jOnWuCjqiZnjxTx1sJipnFIEUHrNz4MaxzpHOcK YjVaIFRWF5YLLylu9FJzwhydqJEvuzfS9pEhlSz6DO/e21R1An8C4uwbBVDoaZOT/XYv wZUZKP10+AI/5+C+9JqHlicDRYp9lXogUipxxQzyjjCJY5wdZDDWVr4A9kqYDCIWUym9 QzHhIxcNleqRWPWoRrcJ3qHOUJXe7LZ3EC3HZGEecMR4hFLPeI3x9ywGT6UEymh3zwqx Ud5w== 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=MFxAZD1w5UhTlzLtE5TmBr2XeUa2P0bLYhndFfGu00E=; b=ME2x9QCuQEkORp24hmxad+U3EMyNnDelp8l209u2VmNoSDMhg3pZiqWkV798lcGbZW qLtUP4AWf0t+z1pxxTQotHGHJpKU0vGIRN9RIcBvMoIwKAv9GA2CF/fLsdhUCV+0FORg rSrBDmsh4fEKRsaFU4eEU5AWBYkcSjqE7gvrKsJUc3pGpsC5o0XijvkdhWjFWNGx092P YtudpV1+bEnSp+KZZp47IpoKv1RADoM7Wf/xGiyJMXvW0T5MUOZaMi9Le3WHNN3CDWZh 4Tx2vtDjU4eRtB3tLTmbonj/xB1xZLxT7CoRVrBJEGDZeqcrncXQ6p+aMzkM7+EYSxuA cfRw== X-Gm-Message-State: APjAAAUMF2yu5HMEe0b1MxsbTD3c6mDsEEh2ZizmDWYmd/YePgSPt5u2 7FWfVc9IXSDe85J8mI8mt7eUuX1vFWnnRsGRg3hAsQ== X-Google-Smtp-Source: APXvYqxQV005fHF+HvaEruj1ZJoqo8PtGXpIj9Fq/xsRTZaI4vzVDhfvWzJdU/SymbK4kv1dKZ8aH8kfkI086k8A0ic= X-Received: by 2002:a63:d908:: with SMTP id r8mr4509167pgg.263.1569349937836; Tue, 24 Sep 2019 11:32:17 -0700 (PDT) MIME-Version: 1.0 References: <20190923222403.22956-1-ndesaulniers@google.com> <20190924182417.GA2714282@archlinux-threadripper> In-Reply-To: <20190924182417.GA2714282@archlinux-threadripper> From: Nick Desaulniers Date: Tue, 24 Sep 2019 11:32:06 -0700 Message-ID: Subject: Re: [PATCH] x86, realmode: explicitly set ENTRY in linker script To: Nathan Chancellor Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , clang-built-linux , "H. Peter Anvin" , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , LKML 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 On Tue, Sep 24, 2019 at 11:24 AM Nathan Chancellor wrote: > > On Mon, Sep 23, 2019 at 03:24:02PM -0700, 'Nick Desaulniers' via Clang Built Linux wrote: > > Linking with ld.lld via $ make LD=ld.lld produces the warning: > > ld.lld: warning: cannot find entry symbol _start; defaulting to 0x1000 > > > > Linking with ld.bfd shows the default entry is 0x1000: > > $ readelf -h arch/x86/realmode/rm/realmode.elf | grep Entry > > Entry point address: 0x1000 > > > > While ld.lld is being pedantic, just set the entry point explicitly, > > instead of depending on the implicit default. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/216 > > Signed-off-by: Nick Desaulniers > > --- > > arch/x86/realmode/rm/realmode.lds.S | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/x86/realmode/rm/realmode.lds.S b/arch/x86/realmode/rm/realmode.lds.S > > index 3bb980800c58..2034f5f79bff 100644 > > --- a/arch/x86/realmode/rm/realmode.lds.S > > +++ b/arch/x86/realmode/rm/realmode.lds.S > > @@ -11,6 +11,7 @@ > > > > OUTPUT_FORMAT("elf32-i386") > > OUTPUT_ARCH(i386) > > +ENTRY(0x1000) > > > > SECTIONS > > { > > -- > > 2.23.0.351.gc4317032e6-goog > > > > This appears to break ld.bfd? > > ld:arch/x86/realmode/rm/realmode.lds:131: syntax error > make[5]: *** [../arch/x86/realmode/rm/Makefile:54: arch/x86/realmode/rm/realmode.elf] Error 1 > make[4]: *** [../arch/x86/realmode/Makefile:20: arch/x86/realmode/rm/realmode.bin] Error 2 > make[3]: *** [../scripts/Makefile.build:509: arch/x86/realmode] Error 2 Thanks for testing. Strange, it seems that ld.bfd doesn't like it as an ENTRY in the linker script, but will accept `-e `. Not sure if that's a bug in ld.bfd, or if ld.lld should error as well? https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Using_ld_the_GNU_Linker/simple-commands.html v2 inbound. -- Thanks, ~Nick Desaulniers