linux/scripts/gen_autoksyms.sh
Quentin Perret 88694cff49 kbuild: generate autoksyms.h early
When doing a cold build, autoksyms.h starts empty, and is updated late
in the build process to have visibility over the symbols used by in-tree
drivers. But since the symbol whitelist is known upfront, it can be used
to pre-populate autoksyms.h and maximize the amount of code that can be
compiled to its final state in a single pass, hence reducing build time.

Do this by using gen_autoksyms.sh to initialize autoksyms.h instead of
creating an empty file.

Acked-by: Nicolas Pitre <nico@fluxnic.net>
Tested-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-03-03 20:49:21 +09:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only
# Create an autoksyms.h header file from the list of all module's needed symbols
# as recorded on the second line of *.mod files and the user-provided symbol
# whitelist.
set -e
output_file="$1"
# Use "make V=1" to debug this script.
case "$KBUILD_VERBOSE" in
*1*)
set -x
;;
esac
# We need access to CONFIG_ symbols
. include/config/auto.conf
ksym_wl=/dev/null
if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST" ]; then
# Use 'eval' to expand the whitelist path and check if it is relative
eval ksym_wl="$CONFIG_UNUSED_KSYMS_WHITELIST"
[ "${ksym_wl}" != "${ksym_wl#/}" ] || ksym_wl="$abs_srctree/$ksym_wl"
if [ ! -f "$ksym_wl" ] || [ ! -r "$ksym_wl" ]; then
echo "ERROR: '$ksym_wl' whitelist file not found" >&2
exit 1
fi
fi
# Generate a new ksym list file with symbols needed by the current
# set of modules.
cat > "$output_file" << EOT
/*
* Automatically generated file; DO NOT EDIT.
*/
EOT
[ -f modules.order ] && modlist=modules.order || modlist=/dev/null
sed 's/ko$/mod/' $modlist |
xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
cat - "$ksym_wl" |
sort -u |
sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"
# Special case for modversions (see modpost.c)
if [ -n "$CONFIG_MODVERSIONS" ]; then
echo "#define __KSYM_module_layout 1" >> "$output_file"
fi