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: 11943969 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 BC394C64E7A for ; Tue, 1 Dec 2020 21:38:13 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id BE30E2086A for ; Tue, 1 Dec 2020 21:38:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="YDu+NEbK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE30E2086A 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-20493-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 15804 invoked by uid 550); 1 Dec 2020 21:37:35 -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 15722 invoked from network); 1 Dec 2020 21:37:34 -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=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=CT9DcYuWQU6UdD10KQsIlD/FvhrdlWMQWVwhuVsMWiHBbWiBnc8V6On1kTk2AUyXGh Snf4XsGkaZaXKqHSvIPRX5VdnY4f/+P+z7uiXQN3UAYJ6DxBFAk5qBon3vOYtIBby6k/ +fsPYo9IwH+4rEoBn7Wo14Vw0dLt1MCgY1TlM+xlG7o+ptRo/JN8tVwbr3fpbRJBHlCy trbtmqAmaByAVD/9LdrtZm3KXiTIqBIzhL6AaYYlCJZJNmbBoOSLCUqByhgE6YGVsjmx 0xJkwcDsfFJraO5T4gvF+82Gt1Gldx4G9a15ByNEVcHGU1H3gXvugGQo1NZ0zDPhlwVt sYXw== X-Gm-Message-State: AOAM531CKzIu6ePPFODstS2UaUYkaDNEyDD5Y7Ru0TXGqS/MSKHGl+/F i/r7SA9vR8uQ6ebTJ25O8EeKWdvNlWdHwdNFlfs= 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 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 */