Commit 9741e07e authored by Jiri Olsa's avatar Jiri Olsa Committed by Andrii Nakryiko
Browse files

kbuild: Unify options for BTF generation for vmlinux and modules 



Using new PAHOLE_FLAGS variable to pass extra arguments to
pahole for both vmlinux and modules BTF data generation.

Adding new scripts/pahole-flags.sh script that detect and
prints pahole options.

[ fixed issues found by kernel test robot ]

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211029125729.70002-1-jolsa@kernel.org
parent 0869e507

Makefile

+3 −0
Original line number Diff line number Diff line
@@ -480,6 +480,8 @@ LZ4 = lz4c 
XZ		= xz

ZSTD		= zstd



PAHOLE_FLAGS	= $(shell PAHOLE=$(PAHOLE) $(srctree)/scripts/pahole-flags.sh)



CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \

		  -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)

NOSTDINC_FLAGS :=
@@ -534,6 +536,7 @@ export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE 
export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE

export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE

export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL

export PAHOLE_FLAGS



# Files to ignore in find ... statements

scripts/Makefile.modfinal

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ quiet_cmd_ld_ko_o = LD [M] $@ 
quiet_cmd_btf_ko = BTF [M] $@

      cmd_btf_ko = 							\

	if [ -f vmlinux ]; then						\

		LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J --btf_base vmlinux $@; \

		LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \

		$(RESOLVE_BTFIDS) -b vmlinux $@; 			\

	else								\

		printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \

scripts/link-vmlinux.sh

+1 −10
Original line number Diff line number Diff line
@@ -205,7 +205,6 @@ vmlinux_link() 
gen_btf()

{

	local pahole_ver

	local extra_paholeopt=



	if ! [ -x "$(command -v ${PAHOLE})" ]; then

		echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
@@ -220,16 +219,8 @@ gen_btf() 


	vmlinux_link ${1}



	if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then

		# pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars

		extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars"

	fi

	if [ "${pahole_ver}" -ge "121" ]; then

		extra_paholeopt="${extra_paholeopt} --btf_gen_floats"

	fi



	info "BTF" ${2}

	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${extra_paholeopt} ${1}

	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}



	# Create ${2} which contains just .BTF section but no symbols. Add

	# SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all

scripts/pahole-flags.sh

0 → 100755
+20 −0
Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0



extra_paholeopt=



if ! [ -x "$(command -v ${PAHOLE})" ]; then

	return

fi



pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')



if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then

	# pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars

	extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars"

fi

if [ "${pahole_ver}" -ge "121" ]; then

	extra_paholeopt="${extra_paholeopt} --btf_gen_floats"

fi



echo ${extra_paholeopt}