From patchwork Tue Dec 1 21:36:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11943935 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=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 2B172C83017 for ; Tue, 1 Dec 2020 21:39:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF32C20C56 for ; Tue, 1 Dec 2020 21:39:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="YDu+NEbK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388655AbgLAVjM (ORCPT ); Tue, 1 Dec 2020 16:39:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389078AbgLAVjM (ORCPT ); Tue, 1 Dec 2020 16:39:12 -0500 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BACBC08E85E for ; Tue, 1 Dec 2020 13:37:23 -0800 (PST) Received: by mail-qk1-x74a.google.com with SMTP id x196so2461905qkb.12 for ; Tue, 01 Dec 2020 13:37:23 -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=IWPxRCPjFejanLxpgRG3fapg45p9YOPZWT66lZNPqfI=; b=YDu+NEbK+WVQ3hPM5go5aRizvBPWGGUzdvz8JEp/EAM6XiJoc9pJY3o1c2yVOjp89i bM5tOhFBbqEU2HQ2OR1Oz9/GYaHkOiYtWb5Q/Up3jv4DGF65KdvTcqz6rms02w5eohLl bSgLnGHcyC3YR0xGck//SCcspRfKindzzlyNPE4Y9xXTCXxQ4vUqhJqdcirb9QLh5+ns ApAi4cfhdsSK/ZIzIp7xZ4Eh09o6zM62jKDTDmzug7/qSo6JjgobotZDPriqLtM88GHc /m6WRULzENBGmq+MzEixv/Y7a6Pjdo782dcWw/2FdAhHAKNAMhOCFWjGtsnxviZBNnlf h74g== 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=IWPxRCPjFejanLxpgRG3fapg45p9YOPZWT66lZNPqfI=; b=D41GDUbAaHCiQSCWQuxjSSU+gSrbpQ39KUiCivklZ67fVTcEMod8HyuCzomY091G51 quQLe9boyn7XeyCUV2sP1xpl5SI6VS+b9aEneJHnkMA/K5iX4WqyeUH0+AxlWwfUCTaF tQZ5+6TZhmbxlOJm14/3LiW9cv+vDyjR/C5LEsP1EbzObZEAxl8EGM8EDE+dblaOGk8o nkrIJyPtJogoLo9Ho966wKWU2ohADTQ5eZebavDNylBJYicpm7ZEFVpDoC466l/gIGQm PJJ7bh3WrnuXCf8BGNhzhEGjX2MksawEh4n+wensPzUDeLoQ12HK8WDNbZpQtAQDPhWE 0ezA== X-Gm-Message-State: AOAM531fJatOuHdfLse2MLe2QAEnEAmxGGJrHfOa8wVNQOjYavnkKPyN sK3WyPpXkgUmfB40vGZQ4qlODQmbQirtzrPvyEE= X-Google-Smtp-Source: ABdhPJzl3kQyAlKR1pr/4OX/xbphbD6nNLxnI7REpTqaNoxBrsxlLak2ddu4/JEFd5wju+8eNvtcAAOR8w+vlfUWVUM= 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:b508:: with SMTP id d8mr5050639qve.8.1606858642454; Tue, 01 Dec 2020 13:37:22 -0800 (PST) Date: Tue, 1 Dec 2020 13:36:56 -0800 In-Reply-To: <20201201213707.541432-1-samitolvanen@google.com> Message-Id: <20201201213707.541432-6-samitolvanen@google.com> Mime-Version: 1.0 References: <20201201213707.541432-1-samitolvanen@google.com> X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [PATCH v8 05/16] 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 */