From ddf41329839f49dadf26973cd845ea160ac1784d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 10 Jun 2024 20:25:16 +0900 Subject: [PATCH] kbuild: refactor variables in scripts/link-vmlinux.sh Clean up the variables in scripts/link-vmlinux.sh - Specify the extra objects directly in vmlinux_link() - Move the AS rule to kallsyms() - Set kallsymso and btf_vmlinux_bin_o where they are generated - Remove unneeded variable, kallsymso_prev - Introduce the btf_data variable - Introduce the strip_debug flag instead of checking the output name No functional change intended. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- scripts/link-vmlinux.sh | 67 +++++++++++++++++++++-------------------- 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 518c70b8db50..3d9d7257143a 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -45,7 +45,6 @@ info() # Link of vmlinux # ${1} - output file -# ${2}, ${3}, ... - optional extra .o files vmlinux_link() { local output=${1} @@ -90,7 +89,7 @@ vmlinux_link() ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}" # The kallsyms linking does not need debug symbols included. - if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then + if [ -n "${strip_debug}" ] ; then ldflags="${ldflags} ${wl}--strip-debug" fi @@ -101,7 +100,7 @@ vmlinux_link() ${ld} ${ldflags} -o ${output} \ ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \ ${wl}--start-group ${libs} ${wl}--end-group \ - $@ ${ldlibs} + ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs} } # generate .BTF typeinfo from DWARF debuginfo @@ -110,6 +109,7 @@ vmlinux_link() gen_btf() { local pahole_ver + local btf_data=${2} if ! [ -x "$(command -v ${PAHOLE})" ]; then echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" @@ -124,16 +124,16 @@ gen_btf() vmlinux_link ${1} - info "BTF" ${2} + info BTF "${btf_data}" LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} - # Create ${2} which contains just .BTF section but no symbols. Add + # Create ${btf_data} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all # deletes all symbols including __start_BTF and __stop_BTF, which will # be redefined in the linker script. Add 2>/dev/null to suppress GNU # objcopy warnings: "empty loadable segment detected at ..." ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ - --strip-all ${1} ${2} 2>/dev/null + --strip-all ${1} "${btf_data}" 2>/dev/null # Change e_type to ET_REL so that it can be used to link final vmlinux. # GNU ld 2.35+ and lld do not allow an ET_EXEC input. if is_enabled CONFIG_CPU_BIG_ENDIAN; then @@ -141,10 +141,12 @@ gen_btf() else et_rel='\1\0' fi - printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none + printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none + + btf_vmlinux_bin_o=${btf_data} } -# Create ${2} .S file with all symbols from the ${1} object file +# Create ${2}.o file with all symbols from the ${1} object file kallsyms() { local kallsymopt; @@ -165,27 +167,25 @@ kallsyms() kallsymopt="${kallsymopt} --lto-clang" fi - info KSYMS ${2} - scripts/kallsyms ${kallsymopt} ${1} > ${2} + info KSYMS "${2}.S" + scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S" + + info AS "${2}.o" + ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ + ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S" + + kallsymso=${2}.o } # Perform one step in kallsyms generation, including temporary linking of # vmlinux. kallsyms_step() { - kallsymso_prev=${kallsymso} kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1} - kallsymso=${kallsyms_vmlinux}.o - kallsyms_S=${kallsyms_vmlinux}.S - vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o} - mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms - kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S} - - info AS ${kallsymso} - ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ - ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ - -c -o ${kallsymso} ${kallsyms_S} + vmlinux_link "${kallsyms_vmlinux}" + mksysmap "${kallsyms_vmlinux}" "${kallsyms_vmlinux}.syms" + kallsyms "${kallsyms_vmlinux}.syms" "${kallsyms_vmlinux}" } # Create map file with all symbols from ${1} @@ -223,19 +223,18 @@ fi ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o -btf_vmlinux_bin_o="" +btf_vmlinux_bin_o= +kallsymso= +strip_debug= + 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 + if ! gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then echo >&2 "Failed to generate BTF for vmlinux" echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" exit 1 fi fi -kallsymso="" -kallsymso_prev="" -kallsyms_vmlinux="" if is_enabled CONFIG_KALLSYMS; then # kallsyms support @@ -261,11 +260,13 @@ if is_enabled CONFIG_KALLSYMS; then # a) Verify that the System.map from vmlinux matches the map from # ${kallsymso}. - kallsyms_step 1 - kallsyms_step 2 + # The kallsyms linking does not need debug symbols included. + strip_debug=1 - # step 3 - size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev}) + kallsyms_step 1 + size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) + + kallsyms_step 2 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then @@ -273,7 +274,9 @@ if is_enabled CONFIG_KALLSYMS; then fi fi -vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} +strip_debug= + +vmlinux_link vmlinux # fill in BTF IDs if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then