From patchwork Fri Oct 9 16:13:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11826513 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 395B81580 for ; Fri, 9 Oct 2020 16:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EED12227E for ; Fri, 9 Oct 2020 16:14:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sEoOB3be" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389715AbgJIQOn (ORCPT ); Fri, 9 Oct 2020 12:14:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389717AbgJIQOI (ORCPT ); Fri, 9 Oct 2020 12:14:08 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BE63C0613D5 for ; Fri, 9 Oct 2020 09:14:08 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id n125so7113673qke.19 for ; Fri, 09 Oct 2020 09:14:08 -0700 (PDT) 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=i0HfMD/wRChzzw+H0j5SIQI+XYlsyfomuEvjB0A2b7U=; b=sEoOB3beinnRwWhTbfM8SalF0cypydPh216467a4z4b5/i0LPdWiZ5comfR+CiYfuB Eu6WnuwqDQWg3zWFoeOdTsPbYHhw3tNqNZ8MjpSQcdjSRgi7EG1dWI1RykapF9xZWiY2 le1HF/WqJI6Jl13HF5R6zyktQuEsBMAEVBeei7ZFW9w6SZcy2RVolvTp6Wll1P+Fel+u qLJQ4BMU4abl2vfwj62MA6cUp201pkizABLlY7j94v8InIgak3mqGIgyVYCkdDVXzKLs jgf681rPIiD2mLYPe4v1fiJI8parpj4mo1rgorOkKlmmsNOrBR5zrp7/pX8UClF3X8DT 0uzg== 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=i0HfMD/wRChzzw+H0j5SIQI+XYlsyfomuEvjB0A2b7U=; b=lxgAAZq1baa0SI5nc9SYfwB9wJTYvqB3nMimZPD0oEDNp6BJAz3GMC7GedOVVUzmAr 7d5F5X0WePGHuOthwkbMF9Uned/+OdWWZDVJH1qW4eskJMDJp+BGVQVB7FOvzYrHjmFF fkm+EaLO+BdrJJpWhzCCzcH7iz8dO+KjoqYEiC/wSvKhdNl4u+IzwkTInO4wn86RtYG8 fn2b3YGgZFzmm+Hqs2d8/rLnlPMIRLah6HT8EEtUQPm0tr3TD2KSuv/fGZQ2jMf2u2Cl K4OYAurHrOaMhZwKu9d/81aU9WiiISTGyCVAVQ4l4gXSyK+oquk94YdOZtLn1zsSchsz LK6Q== X-Gm-Message-State: AOAM530NgY/Yv27Khjmrv+2d612TGohWlfL8Whp4e6SyhG42rdETMeHo vm2lghOjWFntIlFZCyF+wybx59XrYxwRDh7Y35w= X-Google-Smtp-Source: ABdhPJy/D8/0u+nzbzzf55/nK574QK9COSo5VcbQLJEKAJhBGhwXDRm3vwXt4Hczxebu5BRqeLM/xZZizY5eXSIgq20= 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:ad4:456c:: with SMTP id o12mr14223376qvu.48.1602260047185; Fri, 09 Oct 2020 09:14:07 -0700 (PDT) Date: Fri, 9 Oct 2020 09:13:22 -0700 In-Reply-To: <20201009161338.657380-1-samitolvanen@google.com> Message-Id: <20201009161338.657380-14-samitolvanen@google.com> Mime-Version: 1.0 References: <20201009161338.657380-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v5 13/29] kbuild: lto: merge module sections From: Sami Tolvanen To: Masahiro Yamada , Will Deacon , Steven Rostedt Cc: 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, x86@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 | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 69b9b71a6a47..037120173a22 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -25,5 +25,33 @@ SECTIONS { __jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) } } +#ifdef CONFIG_LTO_CLANG +/* + * 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. + */ +SECTIONS { + __patchable_function_entries : { *(__patchable_function_entries) } + + .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_]*) } +} +#endif + /* bring in arch-specific sections */ #include