From patchwork Mon Feb 8 20:28:34 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 61444 Delivered-To: patch@linaro.org Received: by 10.112.43.199 with SMTP id y7csp1659823lbl; Mon, 8 Feb 2016 12:44:52 -0800 (PST) X-Received: by 10.98.18.207 with SMTP id 76mr44377436pfs.53.1454964292388; Mon, 08 Feb 2016 12:44:52 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id tl10si48640524pac.177.2016.02.08.12.44.52; Mon, 08 Feb 2016 12:44:52 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932413AbcBHUob (ORCPT + 30 others); Mon, 8 Feb 2016 15:44:31 -0500 Received: from relais.videotron.ca ([24.201.245.36]:61322 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755920AbcBHUnr (ORCPT ); Mon, 8 Feb 2016 15:43:47 -0500 Content-transfer-encoding: 7BIT Received: from yoda.home ([96.23.157.65]) by VL-VM-MR001.ip.videotron.ca (Oracle Communications Messaging Exchange Server 7u4-22.01 64bit (built Apr 21 2011)) with ESMTP id <0O2800LE4WVSDN10@VL-VM-MR001.ip.videotron.ca>; Mon, 08 Feb 2016 15:28:40 -0500 (EST) Received: from xanadu.home (xanadu.home [192.168.2.2]) by yoda.home (Postfix) with ESMTP id EEA3B2DA053D; Mon, 08 Feb 2016 15:28:39 -0500 (EST) From: Nicolas Pitre To: Michal Marek , linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Al Viro , Rusty Russell Subject: [PATCH 5/6] create/adjust generated/expsyms.h Date: Mon, 08 Feb 2016 15:28:34 -0500 Message-id: <1454963315-20468-6-git-send-email-nicolas.pitre@linaro.org> X-Mailer: git-send-email 2.5.0 In-reply-to: <1454963315-20468-1-git-send-email-nicolas.pitre@linaro.org> References: <1454963315-20468-1-git-send-email-nicolas.pitre@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Given the list of exported symbols needed by all modules, we can create a header file containing preprocessor defines for each of those symbols. Also, when some symbols are added and/or removed from the list, we can update the time on the corresponding files used as build dependencies for those symbols. And finally, if any symbol did change state, the corresponding source files must be rebuilt. The insertion or removal of an EXPORT_SYMBOL() entry within a module may create or remove the need for another exported symbol. This is why this operation has to be repeated until the list of needed exported symbols becomes stable. Only then the final kernel and modules link take place. Signed-off-by: Nicolas Pitre --- Makefile | 13 +++++++ scripts/adjust_expsyms.sh | 97 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 110 insertions(+) create mode 100755 scripts/adjust_expsyms.sh -- 2.5.0 diff --git a/Makefile b/Makefile index 3a264129f8..f904c1d3e8 100644 --- a/Makefile +++ b/Makefile @@ -921,6 +921,10 @@ quiet_cmd_link-vmlinux = LINK $@ # Include targets which we want to # execute if the rest of the kernel build went well. vmlinux: scripts/link-vmlinux.sh $(vmlinux-deps) FORCE +ifdef CONFIG_TRIM_UNUSED_EXPSYMS + $(Q)$(CONFIG_SHELL) scripts/adjust_expsyms.sh \ + "$(MAKE) KBUILD_MODULES=1 -f $(srctree)/Makefile vmlinux_recursive" +endif ifdef CONFIG_HEADERS_CHECK $(Q)$(MAKE) -f $(srctree)/Makefile headers_check endif @@ -935,6 +939,15 @@ ifdef CONFIG_GDB_SCRIPTS endif +$(call if_changed,link-vmlinux) +vmlinux_recursive: $(vmlinux-deps) + $(Q)$(CONFIG_SHELL) scripts/adjust_expsyms.sh \ + "$(MAKE) KBUILD_MODULES=1 -f $(srctree)/Makefile vmlinux_recursive" +PHONY += vmlinux_recursive + +# standalone target for easier testing +include/generated/expsyms.h: FORCE + $(Q)$(CONFIG_SHELL) scripts/adjust_expsyms.sh true + # The actual objects are generated when descending, # make sure no implicit rule kicks in $(sort $(vmlinux-deps)): $(vmlinux-dirs) ; diff --git a/scripts/adjust_expsyms.sh b/scripts/adjust_expsyms.sh new file mode 100755 index 0000000000..f363f4b8ea --- /dev/null +++ b/scripts/adjust_expsyms.sh @@ -0,0 +1,97 @@ +#!/bin/sh + +# Script to create/update include/generated/expsyms.h and dependency files +# +# Copyright: (C) 2016 Linaro Limited +# Created by: Nicolas Pitre, January 2016 +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License version 2 as +# published by the Free Software Foundation. + +# Create/update the include/generated/expsyms.h file from the list +# of all module's needed symbols as recorded on the third line of +# .tmp_versions/*.mod files. +# +# For each symbol being added or removed, the corresponding dependency +# file's timestamp is updated to force a rebuild of the affected source +# file. All arguments passed to this script are assumed to be a command +# to be exec'd that will trigger a rebuild of those files. + +set -e + +cur_expsym_file="include/generated/expsyms.h" +new_expsym_file="include/generated/expsyms.h.tmpnew" + +info() { [ "$quiet" != "silent_" ] && printf " %-7s %s\n" "$1" "$2"; } + +info "CHK" "$cur_expsym_file" + +# Use "make V=1" to debug this script. +case "$KBUILD_VERBOSE" in +*1*) + set -x + ;; +esac + +# We need access to CONFIG_ symbols +case "${KCONFIG_CONFIG}" in +*/*) + . "${KCONFIG_CONFIG}" + ;; +*) + # Force using a file from the current directory + . "./${KCONFIG_CONFIG}" +esac + +# In case it doesn't exist yet... +[ -e "$cur_expsym_file" ] || touch "$cur_expsym_file" + +# Generate a new expsym list file with symbols needed by the current +# set of modules. +cat > "$new_expsym_file" << EOT +/* + * Automatically generated file; DO NOT EDIT. + */ + +EOT +sed -ns -e '3s/ /\n/gp' "$MODVERDIR"/*.mod | sort -u | +while read sym; do + if [ -n "$CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX" ]; then + sym=$(sed 's/_\(.*\)$/\1/' <<< "$sym") + fi + echo "#define __EXPSYM_${sym} 1" +done >> "$new_expsym_file" + +# Special case for modversions (see modpost.c) +if [ -n "$CONFIG_MODVERSIONS" ]; then + echo "#define __EXPSYM_module_layout 1" >> "$new_expsym_file" +fi + +# Extract changes between old and new list and touch corresponding +# dependency files. +# Note: sort -m doesn't work well with underscore prefixed symbols so we +# use 'cat ... | sort' instead. +changed=0 +while read sympath; do + [ -z "$sympath" ] && continue + depfile="include/config/expsym/${sympath}.h" + mkdir -p "$(dirname "$depfile")" + touch "$depfile" + changed=$((changed + 1)) +done <<< "$( + cat "$cur_expsym_file" "$new_expsym_file" | sort | uniq -u | + sed -n 's/^#define __EXPSYM_\(.*\) 1/\1/p' | tr "A-Z_" "a-z/" )" + +if [ $changed -gt 0 ]; then + # Replace the old list with tne new one + old=$(grep -c "^#define __EXPSYM_" "$cur_expsym_file" || true) + new=$(grep -c "^#define __EXPSYM_" "$new_expsym_file" || true) + info "EXPSYM" "symbols: $old old, $new new, $changed changed" + info "UPD" "$cur_expsym_file" + mv -f "$new_expsym_file" "$cur_expsym_file" + # Then trigger a rebuild of affected files + exec $@ +else + rm -f "$new_expsym_file" +fi