1#!/bin/sh
2#
3# Copyright © 2008 IBM Corporation
4#
5# This program is free software; you can redistribute it and/or
6# modify it under the terms of the GNU General Public License
7# as published by the Free Software Foundation; either version
8# 2 of the License, or (at your option) any later version.
9
10# This script checks prom_init.o to see what external symbols it
11# is using, if it finds symbols not in the whitelist it returns
12# an error. The point of this is to discourage people from
13# intentionally or accidentally adding new code to prom_init.c
14# which has side effects on other parts of the kernel.
15
16# If you really need to reference something from prom_init.o add
17# it to the list below:
18
19WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
20_end enter_prom memcpy memset reloc_offset __secondary_hold
21__secondary_hold_acknowledge __secondary_hold_spinloop __start
22strcmp strcpy strlcpy strlen strncmp strstr logo_linux_clut224
23reloc_got2 kernstart_addr memstart_addr linux_banner _stext
24opal_query_takeover opal_do_takeover opal_enter_rtas opal_secondary_entry
25boot_command_line __prom_init_toc_start __prom_init_toc_end"
26
27NM="$1"
28OBJ="$2"
29
30ERROR=0
31
32for UNDEF in $($NM -u $OBJ | awk '{print $2}')
33do
34	# On 64-bit nm gives us the function descriptors, which have
35	# a leading . on the name, so strip it off here.
36	UNDEF="${UNDEF#.}"
37
38	if [ $KBUILD_VERBOSE ]; then
39		if [ $KBUILD_VERBOSE -ne 0 ]; then
40			echo "Checking prom_init.o symbol '$UNDEF'"
41		fi
42	fi
43
44	OK=0
45	for WHITE in $WHITELIST
46	do
47		if [ "$UNDEF" = "$WHITE" ]; then
48			OK=1
49			break
50		fi
51	done
52
53	# ignore register save/restore funcitons
54	if [ "${UNDEF:0:9}" = "_restgpr_" ]; then
55		OK=1
56	fi
57	if [ "${UNDEF:0:10}" = "_restgpr0_" ]; then
58		OK=1
59	fi
60	if [ "${UNDEF:0:11}" = "_rest32gpr_" ]; then
61		OK=1
62	fi
63	if [ "${UNDEF:0:9}" = "_savegpr_" ]; then
64		OK=1
65	fi
66	if [ "${UNDEF:0:10}" = "_savegpr0_" ]; then
67		OK=1
68	fi
69	if [ "${UNDEF:0:11}" = "_save32gpr_" ]; then
70		OK=1
71	fi
72
73	if [ $OK -eq 0 ]; then
74		ERROR=1
75		echo "Error: External symbol '$UNDEF' referenced" \
76		     "from prom_init.c" >&2
77	fi
78done
79
80exit $ERROR
81