From 7d153696e5db1e37387c2f7ec06ffc8d4aac70a4 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 14 Dec 2021 11:53:52 +0900 Subject: kbuild: do not include include/config/auto.conf from shell scripts Richard Weinberger pointed out the risk of sourcing the kernel config from shell scripts [1], and proposed some patches [2], [3]. It is a good point, but it took a long time because I was wondering how to fix this. This commit goes with simple grep approach because there are only a few scripts including the kernel configuration. scripts/link_vmlinux.sh has references to a bunch of CONFIG options, all of which are boolean. I added is_enabled() helper as scripts/package/{mkdebian,builddeb} do. scripts/gen_autoksyms.sh uses 'eval', stating "to expand the whitelist path". I removed it since it is the issue we are trying to fix. I was a bit worried about the cost of invoking the grep command over again. I extracted the grep parts from it, and measured the cost. It was approximately 0.03 sec, which I hope is acceptable. [test code] $ cat test-grep.sh #!/bin/sh is_enabled() { grep -q "^$1=y" include/config/auto.conf } is_enabled CONFIG_LTO_CLANG is_enabled CONFIG_LTO_CLANG is_enabled CONFIG_STACK_VALIDATION is_enabled CONFIG_UNWINDER_ORC is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL is_enabled CONFIG_VMLINUX_VALIDATION is_enabled CONFIG_FRAME_POINTER is_enabled CONFIG_GCOV_KERNEL is_enabled CONFIG_LTO_CLANG is_enabled CONFIG_RETPOLINE is_enabled CONFIG_X86_SMAP is_enabled CONFIG_LTO_CLANG is_enabled CONFIG_VMLINUX_MAP is_enabled CONFIG_KALLSYMS_ALL is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU is_enabled CONFIG_KALLSYMS_BASE_RELATIVE is_enabled CONFIG_DEBUG_INFO_BTF is_enabled CONFIG_KALLSYMS is_enabled CONFIG_DEBUG_INFO_BTF is_enabled CONFIG_BPF is_enabled CONFIG_BUILDTIME_TABLE_SORT is_enabled CONFIG_KALLSYMS $ time ./test-grep.sh real 0m0.036s user 0m0.027s sys m0.009s [1]: https://lore.kernel.org/all/1919455.eZKeABUfgV@blindfold/ [2]: https://lore.kernel.org/all/20180219092245.26404-1-richard@nod.at/ [3]: https://lore.kernel.org/all/20210920213957.1064-2-richard@nod.at/ Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- scripts/link-vmlinux.sh | 47 ++++++++++++++++++++++++----------------------- 1 file changed, 24 insertions(+), 23 deletions(-) (limited to 'scripts/link-vmlinux.sh') diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 5cdd9bc5c385..a4b61a2f65db 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -34,6 +34,10 @@ LD="$1" KBUILD_LDFLAGS="$2" LDFLAGS_vmlinux="$3" +is_enabled() { + grep -q "^$1=y" include/config/auto.conf +} + # Nice output in kbuild format # Will be supressed by "make -s" info() @@ -80,11 +84,11 @@ modpost_link() ${KBUILD_VMLINUX_LIBS} \ --end-group" - if [ -n "${CONFIG_LTO_CLANG}" ]; then + if is_enabled CONFIG_LTO_CLANG; then gen_initcalls lds="-T .tmp_initcalls.lds" - if [ -n "${CONFIG_MODVERSIONS}" ]; then + if is_enabled CONFIG_MODVERSIONS; then gen_symversions lds="${lds} -T .tmp_symversions.lds" fi @@ -104,21 +108,21 @@ objtool_link() local objtoolcmd; local objtoolopt; - if [ "${CONFIG_LTO_CLANG} ${CONFIG_STACK_VALIDATION}" = "y y" ]; then + if is_enabled CONFIG_LTO_CLANG && is_enabled CONFIG_STACK_VALIDATION; then # Don't perform vmlinux validation unless explicitly requested, # but run objtool on vmlinux.o now that we have an object file. - if [ -n "${CONFIG_UNWINDER_ORC}" ]; then + if is_enabled CONFIG_UNWINDER_ORC; then objtoolcmd="orc generate" fi objtoolopt="${objtoolopt} --duplicate" - if [ -n "${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL}" ]; then + if is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL; then objtoolopt="${objtoolopt} --mcount" fi fi - if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then + if is_enabled CONFIG_VMLINUX_VALIDATION; then objtoolopt="${objtoolopt} --noinstr" fi @@ -127,16 +131,16 @@ objtool_link() objtoolcmd="check" fi objtoolopt="${objtoolopt} --vmlinux" - if [ -z "${CONFIG_FRAME_POINTER}" ]; then + if ! is_enabled CONFIG_FRAME_POINTER; then objtoolopt="${objtoolopt} --no-fp" fi - if [ -n "${CONFIG_GCOV_KERNEL}" ] || [ -n "${CONFIG_LTO_CLANG}" ]; then + if is_enabled CONFIG_GCOV_KERNEL || is_enabled CONFIG_LTO_CLANG; then objtoolopt="${objtoolopt} --no-unreachable" fi - if [ -n "${CONFIG_RETPOLINE}" ]; then + if is_enabled CONFIG_RETPOLINE; then objtoolopt="${objtoolopt} --retpoline" fi - if [ -n "${CONFIG_X86_SMAP}" ]; then + if is_enabled CONFIG_X86_SMAP; then objtoolopt="${objtoolopt} --uaccess" fi info OBJTOOL ${1} @@ -161,7 +165,7 @@ vmlinux_link() # skip output file argument shift - if [ -n "${CONFIG_LTO_CLANG}" ]; then + if is_enabled CONFIG_LTO_CLANG; then # Use vmlinux.o instead of performing the slow LTO link again. objs=vmlinux.o libs= @@ -189,7 +193,7 @@ vmlinux_link() ldflags="${ldflags} ${wl}--strip-debug" fi - if [ -n "${CONFIG_VMLINUX_MAP}" ]; then + if is_enabled CONFIG_VMLINUX_MAP; then ldflags="${ldflags} ${wl}-Map=${output}.map" fi @@ -239,15 +243,15 @@ kallsyms() { local kallsymopt; - if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then + if is_enabled CONFIG_KALLSYMS_ALL; then kallsymopt="${kallsymopt} --all-symbols" fi - if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then + if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then kallsymopt="${kallsymopt} --absolute-percpu" fi - if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then + if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then kallsymopt="${kallsymopt} --base-relative" fi @@ -312,9 +316,6 @@ if [ "$1" = "clean" ]; then exit 0 fi -# We need access to CONFIG_ symbols -. include/config/auto.conf - # Update version info GEN .version if [ -r .version ]; then @@ -343,7 +344,7 @@ tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' | tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin btf_vmlinux_bin_o="" -if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then +if is_enabled CONFIG_DEBUG_INFO_BTF; then btf_vmlinux_bin_o=.btf.vmlinux.bin.o if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then echo >&2 "Failed to generate BTF for vmlinux" @@ -355,7 +356,7 @@ fi kallsymso="" kallsymso_prev="" kallsyms_vmlinux="" -if [ -n "${CONFIG_KALLSYMS}" ]; then +if is_enabled CONFIG_KALLSYMS; then # kallsyms support # Generate section listing all symbols and add it into vmlinux @@ -395,12 +396,12 @@ fi vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} # fill in BTF IDs -if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then +if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then info BTFIDS vmlinux ${RESOLVE_BTFIDS} vmlinux fi -if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then +if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then info SORTTAB vmlinux if ! sorttable vmlinux; then echo >&2 Failed to sort kernel tables @@ -412,7 +413,7 @@ info SYSMAP System.map mksysmap vmlinux System.map # step a (see comment above) -if [ -n "${CONFIG_KALLSYMS}" ]; then +if is_enabled CONFIG_KALLSYMS; then mksysmap ${kallsyms_vmlinux} .tmp_System.map if ! cmp -s System.map .tmp_System.map; then -- cgit v1.2.3