[PATCHv2 bpf-next] kbuild: Unify options for BTF generation for vmlinux and modules
From: Jiri Olsa <hidden>
Date: 2021-10-26 21:24:26
Also in:
bpf, linux-kbuild
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
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. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- v2 changes: - posting separately from original patchset - added Andrii's ack Makefile | 3 +++ scripts/Makefile.modfinal | 2 +- scripts/link-vmlinux.sh | 11 +---------- scripts/pahole-flags.sh | 20 ++++++++++++++++++++ 4 files changed, 25 insertions(+), 11 deletions(-) create mode 100755 scripts/pahole-flags.sh
diff --git a/Makefile b/Makefile
index 437ccc66a1c2..ee514b80c62e 100644
--- a/Makefile
+++ b/Makefile@@ -480,6 +480,8 @@ LZ4 = lz4c XZ = xz ZSTD = zstd +PAHOLE_FLAGS = $(shell PAHOLE=$(PAHOLE) 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
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 1fb45b011e4b..7f39599e9fae 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal@@ -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" $@ 1>&2; \
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index d74cee5c4326..3ea7cece7c97 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh@@ -205,7 +205,6 @@ vmlinux_link() gen_btf() { local pahole_ver - local extra_paholeopt= if ! [ -x "$(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 ${2} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
new file mode 100755
index 000000000000..2b99fc77019c
--- /dev/null
+++ b/scripts/pahole-flags.sh@@ -0,0 +1,20 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +extra_paholeopt= + +if ! [ -x "$(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}
--
2.31.1