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

1 files changed, 20 insertions, 0 deletions

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}