From patchwork Fri Dec 11 18:46:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11969045 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 B27D9C4361B for ; Fri, 11 Dec 2020 18:47:40 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id D725923F59 for ; Fri, 11 Dec 2020 18:47:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D725923F59 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-20587-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 6139 invoked by uid 550); 11 Dec 2020 18:46:58 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 6060 invoked from network); 11 Dec 2020 18:46:57 -0000 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=NmW10Ys2Tgg9pvNOzRC87vTxzQN/QNTXAjHd7AFTV8ok00h9tGhhYMLsRuxKeNhXDl iMPagwzzegEY0NAWkP8VdeyEnPICgOM5AE4FTcCbPPAinuDjGz68sbCLgXPYhkRq1Pep /oDzt2sWciOe12Hb0BMOoaCF9qAfZgz+jdivhEhkTAz3ohV7gcdM13QrPXPixLmDjCSe nTPKcCoKQq0gq3xcii2Dkj1W1xDXw/X3VKykyVsM1VgUoEe62p+1hemZShAFUHpH1Tsi 8OfLqN3hCowWbgVvrwWk8fm6stKJ1NblXBwjNE+NVf/Ofnn3fkAOASnNgDC94IzGVftK 2nnw== 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=n860g/hg8XvFhaseVCYkfPQY+xbyPeTNd8+WskloZcjIekSbXtvMVxZ5ioSUwo0P7u wlzHhXxzvZgpcB8R19kYfhTSdqSk8P9Etk0bJ5GCZLeVsM4kczQogmwxS5ezXj/1d8DR IuupaAk15BtLoUIIqMVxFKlYMrhRB0tjdFu5onB7bhk7av5gdRGN5mcC+KEfjimcRll+ j/VR9gWv3LB57y/A38FwFrRI8G+N+Mm+/ymzokoVi5o+zVR73XB9xNV7zPQXPU7fp+KJ HW7VT+o7eGNAy/s6wyyufjAgkEAax6soZhhAR5LCwcASJBClwXX3rrpO088YOnt3U/Gg BdbQ== X-Gm-Message-State: AOAM531gWjg1gcDhEdp0droqfvMAeZsO6mnuDXDBYa2W1DXoyxEMNZ0y pt+n7RVfWsgSb6oGIDKnWf+/kUyyrKSCXKAYK1U= X-Google-Smtp-Source: ABdhPJzm7bBo2qDvtUgK6v6rrLGQ/0dJj/ATzhcF3Fgu3P9N3k/LVow1+5c7Y8w8YkEUkh1r4Djckvq7KIZM8TNXHU4= 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:a17:90a:8b94:: with SMTP id z20mr136813pjn.1.1607712405109; Fri, 11 Dec 2020 10:46:45 -0800 (PST) Date: Fri, 11 Dec 2020 10:46:22 -0800 In-Reply-To: <20201211184633.3213045-1-samitolvanen@google.com> Message-Id: <20201211184633.3213045-6-samitolvanen@google.com> Mime-Version: 1.0 References: <20201211184633.3213045-1-samitolvanen@google.com> X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [PATCH v9 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 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 */