linux/scripts/gen_autoksyms.sh
Masahiro Yamada a6aaeb8411 kbuild: fix UNUSED_KSYMS_WHITELIST for Clang LTO
Commit fbe078d397 ("kbuild: lto: add a default list of used symbols")
does not work as expected if the .config file has already specified
CONFIG_UNUSED_KSYMS_WHITELIST="my/own/white/list" before enabling
CONFIG_LTO_CLANG.

So, the user-supplied whitelist and LTO-specific white list must be
independent of each other.

I refactored the shell script so CONFIG_MODVERSIONS and CONFIG_CLANG_LTO
handle whitelists in the same way.

Fixes: fbe078d397 ("kbuild: lto: add a default list of used symbols")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
2021-02-28 15:19:21 +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
needed_symbols=
# Special case for modversions (see modpost.c)
if [ -n "$CONFIG_MODVERSIONS" ]; then
needed_symbols="$needed_symbols module_layout"
fi
# With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a binary
# when the .mod files are generated, which means they don't yet contain
# references to certain symbols that will be present in the final binaries.
if [ -n "$CONFIG_LTO_CLANG" ]; then
# intrinsic functions
needed_symbols="$needed_symbols memcpy memmove memset"
# ftrace
needed_symbols="$needed_symbols _mcount"
# stack protector symbols
needed_symbols="$needed_symbols __stack_chk_fail __stack_chk_guard"
fi
ksym_wl=
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/' $modlist | xargs -n1 sed -n -e '2p'
echo "$needed_symbols"
[ -n "$ksym_wl" ] && cat "$ksym_wl"
} | sed -e 's/ /\n/g' | sed -n -e '/^$/!p' |
# Remove the dot prefix for ppc64; symbol names with a dot (.) hold entry
# point addresses.
sed -e 's/^\.//' |
sort -u |
sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"