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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 58AEBC10F0E for ; Tue, 16 Apr 2019 03:23:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 278AD20868 for ; Tue, 16 Apr 2019 03:23:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="EIDu9VBM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726684AbfDPDXo (ORCPT ); Mon, 15 Apr 2019 23:23:44 -0400 Received: from mail-vk1-f195.google.com ([209.85.221.195]:34589 "EHLO mail-vk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726214AbfDPDXn (ORCPT ); Mon, 15 Apr 2019 23:23:43 -0400 Received: by mail-vk1-f195.google.com with SMTP id x84so4117883vkd.1 for ; Mon, 15 Apr 2019 20:23:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gEc6RSrTv8OkG4Xv9qNrDhE3A/ZV8wCYsiS9vzqwUUU=; b=EIDu9VBMPmOoEa3D47obgN22EGFQcR/ZNUcE8oGSi1qWO67ppq1dsB7GtIZRLDCUuh yLonBkGUMZopRZP9/raMRZ0jTjMMDyVUfB8C0SvtSwKUT1g/35tlZGeCCwbDz34fVja7 RfOj8EP31+zaNs0ZUd1Fuik/jgi2Fnx6VNfH4= 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=gEc6RSrTv8OkG4Xv9qNrDhE3A/ZV8wCYsiS9vzqwUUU=; b=WNZqnhCV0leWYHv28rwiIMeahSU3zh/oTg9nAfF5CiTrkNPZY0kHf983o0ecHUMgDl xQoewuKWEtyCLEvgFWZI1xgooG5owTozAdaA4bimdcWNk9UFS3P1aeGptMLzN+9d0d1j Rr5BZ/LNG0ptqZz7u5AHP6XZ2SDjhS87vjfeisqy2oBwmnsImvBRu4LkRXJWXUMJ0hc4 dfe2TQDat2UCrXxFcLyxkwLd8mk428ooRDt4B14aKuR9dXoiP9BYOaCfRl6a3feuHH98 GGJU/p4wgMzZBsxaNF7ogS/xJw8TvFfuCICMUO/xTVF/gjtJ2J9UkCyFsR3xWu958eDE DtVg== X-Gm-Message-State: APjAAAWttl2W/iWLQRtionzePRT+KvdhYhv4RuxLdbQpoZZF8SJ0RdJ4 ZiedWACXm6Iva+i00USM0m7DDlPC810= X-Google-Smtp-Source: APXvYqzH9hKA2y+rNVza2JjUdBtR4ROZ0cZU4HIWak8+hvCfNdc4jrne3+aGcZ97KaA/naP2qWkXrw== X-Received: by 2002:a1f:8991:: with SMTP id l139mr39160173vkd.49.1555385021992; Mon, 15 Apr 2019 20:23:41 -0700 (PDT) Received: from mail-vk1-f179.google.com (mail-vk1-f179.google.com. [209.85.221.179]) by smtp.gmail.com with ESMTPSA id 20sm10474128uas.15.2019.04.15.20.23.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 Apr 2019 20:23:41 -0700 (PDT) Received: by mail-vk1-f179.google.com with SMTP id h71so4119479vkf.5 for ; Mon, 15 Apr 2019 20:23:40 -0700 (PDT) X-Received: by 2002:a1f:7d4e:: with SMTP id y75mr42015570vkc.53.1555385020477; Mon, 15 Apr 2019 20:23:40 -0700 (PDT) MIME-Version: 1.0 References: <20190415164956.124067-1-samitolvanen@google.com> In-Reply-To: <20190415164956.124067-1-samitolvanen@google.com> From: Kees Cook Date: Mon, 15 Apr 2019 22:23:28 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] x86: fix .bss with -fdata-sections To: Sami Tolvanen , Ingo Molnar Cc: Thomas Gleixner , Borislav Petkov , "H . Peter Anvin" , Nicholas Piggin , X86 ML , LKML , Kees Cook , Nick Desaulniers 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 Mon, Apr 15, 2019 at 11:50 AM Sami Tolvanen wrote: > > With LD_DEAD_CODE_DATA_ELIMINATION, we compile the kernel with > -fdata-sections, which also splits the .bss section. Use the > common BSS_MAIN macro in the linker script to properly merge all > the generated sections. > > Signed-off-by: Sami Tolvanen Nice work tracking this down! :) Reviewed-by: Kees Cook Nit/tweak/clarification for commit title: x86/build: Fix truncated .bss with -fdata-sections -Kees > --- > arch/x86/kernel/vmlinux.lds.S | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S > index bad8c51fee6e..a5127b2c195f 100644 > --- a/arch/x86/kernel/vmlinux.lds.S > +++ b/arch/x86/kernel/vmlinux.lds.S > @@ -362,7 +362,7 @@ SECTIONS > .bss : AT(ADDR(.bss) - LOAD_OFFSET) { > __bss_start = .; > *(.bss..page_aligned) > - *(.bss) > + *(BSS_MAIN) > BSS_DECRYPTED > . = ALIGN(PAGE_SIZE); > __bss_stop = .; > -- > 2.21.0.392.gf8f6787159e-goog > -- Kees Cook