From patchwork Wed Nov 18 22:07:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11915919 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=-26.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,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 D6220C64E7D for ; Wed, 18 Nov 2020 22:07:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77779246E1 for ; Wed, 18 Nov 2020 22:07:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JUEhAG5/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727312AbgKRWHq (ORCPT ); Wed, 18 Nov 2020 17:07:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbgKRWHp (ORCPT ); Wed, 18 Nov 2020 17:07:45 -0500 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00397C061A51 for ; Wed, 18 Nov 2020 14:07:43 -0800 (PST) Received: by mail-qv1-xf4a.google.com with SMTP id k5so2506534qvu.10 for ; Wed, 18 Nov 2020 14:07:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=7xcmRRx6qvqOlAhBXvPUxdlcJiFGDszFPn6Uy8LsYGg=; b=JUEhAG5/26jx0k7UneLL1f8TdMXEdBCuTZJVLjQZ+iZWRpM2bbt0EXRlMyK8xh/rhj JL4aCETLnrd/8DvtoDDkLX34DHCsBE1h9hQQTOHP3TNRNJUaUtVu/5oPiKBq0scCRP6Z +kh1Oyf9NPyMM2Lo7bgcXU9P4bjc/YYA21H9WcxDydQqHpZaclET/mWLe+Q6TCvtF3wo mKxhKgjFnSmEhpPgl/7XzG7iiLKXi7xIewYjRRnbWXMkQNf1t/hl5/7hnFoxRkDw2MOb rVfAfcrlGtLV3PMRjEVyZEJWFeaaAKgzOew1LFSh6KyTd7yH/s0nFEbQGjmL0toalfsR lLAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=7xcmRRx6qvqOlAhBXvPUxdlcJiFGDszFPn6Uy8LsYGg=; b=llkB9Xjmu9vGz3iUTJdnBqs8FHV3Z8zA/lVSM/Q4rEFynaAb6Zfr5OyjUQ5kxx+Sgk JN1pcg+0wkh1o/U+aw0vPJ+wr0ExfT3TFOzlzE12JbCKXPsbMc35f9oSZHKraJUUBbLQ mxSpnHxPYgGSxzT/nm9Qy2BikLNCaXEf7PfjbItEwdsF+bsBeQU3v4oiCGkkBy7Corll 5w9i0FZ/3fam9dA3jts/xL6IT6jGoZQFxPzboWlzWU/Mumxx8cOvMmawTtq+QTOmdXnZ M0wIKYtjZfQL1E/VUNbPvOe1eJ1mxUn8eZdkJ5a9mfWg/D0ddzwwPsT1M2Faq3sEiRfi wpbw== X-Gm-Message-State: AOAM531zhKIMKNDtPtViohx2Cpl5QalRuPt9lFrn+vBp3pprlnCLE5CY 3x/FlJ3UeJTrkM5OQpTKSLyVPGermdABR1doxv8= X-Google-Smtp-Source: ABdhPJwZi43l7NEtfrn2Ph6B8PwX83axN27eYs3bBjDKHIbJhot79HMgDc9/Lz03zP5kBQUcskAGDJr3yB94zqzoXoQ= Sender: "samitolvanen via sendgmr" X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a0c:8004:: with SMTP id 4mr7501644qva.5.1605737263123; Wed, 18 Nov 2020 14:07:43 -0800 (PST) Date: Wed, 18 Nov 2020 14:07:19 -0800 In-Reply-To: <20201118220731.925424-1-samitolvanen@google.com> Message-Id: <20201118220731.925424-6-samitolvanen@google.com> Mime-Version: 1.0 References: <20201118220731.925424-1-samitolvanen@google.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH v7 05/17] kbuild: lto: merge module sections From: Sami Tolvanen To: Masahiro Yamada , Steven Rostedt , Will Deacon Cc: Josh Poimboeuf , Peter Zijlstra , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Sami Tolvanen Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org LLD always splits sections with LTO, which increases module sizes. This change adds linker script rules to merge the split sections in the final module. Suggested-by: Nick Desaulniers Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- scripts/module.lds.S | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 69b9b71a6a47..18d5b8423635 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -23,6 +23,30 @@ SECTIONS { .init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) } __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) } + + __patchable_function_entries : { *(__patchable_function_entries) } + + /* + * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and + * -ffunction-sections, which increases the size of the final module. + * Merge the split sections in the final binary. + */ + .bss : { + *(.bss .bss.[0-9a-zA-Z_]*) + *(.bss..L*) + } + + .data : { + *(.data .data.[0-9a-zA-Z_]*) + *(.data..L*) + } + + .rodata : { + *(.rodata .rodata.[0-9a-zA-Z_]*) + *(.rodata..L*) + } + + .text : { *(.text .text.[0-9a-zA-Z_]*) } } /* bring in arch-specific sections */