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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
kbuild: fix UNUSED_KSYMS_WHITELIST for Clang LTO
Commit fbe078d397b4 ("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: fbe078d397b4 ("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>
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init/Kconfig
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init/Kconfig
···
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config UNUSED_KSYMS_WHITELIST
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string "Whitelist of symbols to keep in ksymtab"
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depends on TRIM_UNUSED_KSYMS
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default "scripts/lto-used-symbollist.txt" if LTO_CLANG
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help
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By default, all unused exported symbols will be un-exported from the
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build when TRIM_UNUSED_KSYMS is selected.
+26
-9
scripts/gen_autoksyms.sh
+26
-9
scripts/gen_autoksyms.sh
···
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# We need access to CONFIG_ symbols
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. include/config/auto.conf
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ksym_wl=/dev/null
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needed_symbols=
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# Special case for modversions (see modpost.c)
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if [ -n "$CONFIG_MODVERSIONS" ]; then
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needed_symbols="$needed_symbols module_layout"
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fi
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# With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a binary
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# when the .mod files are generated, which means they don't yet contain
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# references to certain symbols that will be present in the final binaries.
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if [ -n "$CONFIG_LTO_CLANG" ]; then
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# intrinsic functions
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needed_symbols="$needed_symbols memcpy memmove memset"
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# ftrace
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needed_symbols="$needed_symbols _mcount"
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# stack protector symbols
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needed_symbols="$needed_symbols __stack_chk_fail __stack_chk_guard"
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fi
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ksym_wl=
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if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST" ]; then
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# Use 'eval' to expand the whitelist path and check if it is relative
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eval ksym_wl="$CONFIG_UNUSED_KSYMS_WHITELIST"
···
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EOT
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[ -f modules.order ] && modlist=modules.order || modlist=/dev/null
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-
sed 's/ko$/mod/' $modlist |
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xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
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cat - "$ksym_wl" |
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{
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sed 's/ko$/mod/' $modlist | xargs -n1 sed -n -e '2p'
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echo "$needed_symbols"
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[ -n "$ksym_wl" ] && cat "$ksym_wl"
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} | sed -e 's/ /\n/g' | sed -n -e '/^$/!p' |
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# Remove the dot prefix for ppc64; symbol names with a dot (.) hold entry
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# point addresses.
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sed -e 's/^\.//' |
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sort -u |
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sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"
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# Special case for modversions (see modpost.c)
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if [ -n "$CONFIG_MODVERSIONS" ]; then
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echo "#define __KSYM_module_layout 1" >> "$output_file"
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fi