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: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211029125729.70002-1-jolsa@kernel.org
This commit is contained in:
Jiri Olsa 2021-10-29 14:57:29 +02:00 committed by Andrii Nakryiko
parent 0869e5078a
commit 9741e07ece
4 changed files with 25 additions and 11 deletions

View File

@ -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

View File

@ -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; \

View File

@ -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

20
scripts/pahole-flags.sh Executable file
View File

@ -0,0 +1,20 @@
#!/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}