1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0-or-later
3
4# Copyright © 2015 IBM Corporation
5
6
7# This script checks the relocations of a vmlinux for "suspicious"
8# relocations.
9
10# based on relocs_check.pl
11# Copyright © 2009 IBM Corporation
12
13if [ $# -lt 3 ]; then
14	echo "$0 [path to objdump] [path to nm] [path to vmlinux]" 1>&2
15	exit 1
16fi
17
18# Have Kbuild supply the path to objdump and nm so we handle cross compilation.
19objdump="$1"
20nm="$2"
21vmlinux="$3"
22
23# Remove from the bad relocations those that match an undefined weak symbol
24# which will result in an absolute relocation to 0.
25# Weak unresolved symbols are of that form in nm output:
26# "                  w _binary__btf_vmlinux_bin_end"
27undef_weak_symbols=$($nm "$vmlinux" | awk '$1 ~ /w/ { print $2 }')
28
29bad_relocs=$(
30$objdump -R "$vmlinux" |
31	# Only look at relocation lines.
32	grep -E '\<R_' |
33	# These relocations are okay
34	# On PPC64:
35	#	R_PPC64_RELATIVE, R_PPC64_NONE
36	# On PPC:
37	#	R_PPC_RELATIVE, R_PPC_ADDR16_HI,
38	#	R_PPC_ADDR16_HA,R_PPC_ADDR16_LO,
39	#	R_PPC_NONE
40	grep -F -w -v 'R_PPC64_RELATIVE
41R_PPC64_NONE
42R_PPC_ADDR16_LO
43R_PPC_ADDR16_HI
44R_PPC_ADDR16_HA
45R_PPC_RELATIVE
46R_PPC_NONE' |
47	([ "$undef_weak_symbols" ] && grep -F -w -v "$undef_weak_symbols" || cat)
48)
49
50if [ -z "$bad_relocs" ]; then
51	exit 0
52fi
53
54num_bad=$(echo "$bad_relocs" | wc -l)
55echo "WARNING: $num_bad bad relocations"
56echo "$bad_relocs"
57
58# If we see this type of relocation it's an idication that
59# we /may/ be using an old version of binutils.
60if echo "$bad_relocs" | grep -q -F -w R_PPC64_UADDR64; then
61	echo "WARNING: You need at least binutils >= 2.19 to build a CONFIG_RELOCATABLE kernel"
62fi
63