1#!/bin/sh
 2# SPDX-License-Identifier: GPL-2.0-or-later
 3#
 4# Copyright © 2008 IBM Corporation
 5#
 
 
 
 
 6
 7# This script checks prom_init.o to see what external symbols it
 8# is using, if it finds symbols not in the whitelist it returns
 9# an error. The point of this is to discourage people from
10# intentionally or accidentally adding new code to prom_init.c
11# which has side effects on other parts of the kernel.
12
13# If you really need to reference something from prom_init.o add
14# it to the list below:
15
16grep "^CONFIG_KASAN=y$" .config >/dev/null
17if [ $? -eq 0 ]
18then
19	MEM_FUNCS="__memcpy __memset"
20else
21	MEM_FUNCS="memcpy memset"
22fi
23
24WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
25_end enter_prom $MEM_FUNCS reloc_offset __secondary_hold
26__secondary_hold_acknowledge __secondary_hold_spinloop __start
27logo_linux_clut224 btext_prepare_BAT
28reloc_got2 kernstart_addr memstart_addr linux_banner _stext
29__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC.
30relocate"
31
32NM="$1"
33OBJ="$2"
34
35ERROR=0
36
37check_section()
38{
39    file=$1
40    section=$2
41    size=$(objdump -h -j $section $file 2>/dev/null | awk "\$2 == \"$section\" {print \$3}")
42    size=${size:-0}
43    if [ $size -ne 0 ]; then
44	ERROR=1
45	echo "Error: Section $section not empty in prom_init.c" >&2
46    fi
47}
48
49for UNDEF in $($NM -u $OBJ | awk '{print $2}')
50do
51	# On 64-bit nm gives us the function descriptors, which have
52	# a leading . on the name, so strip it off here.
53	UNDEF="${UNDEF#.}"
54
55	if [ $KBUILD_VERBOSE ]; then
56		if [ $KBUILD_VERBOSE -ne 0 ]; then
57			echo "Checking prom_init.o symbol '$UNDEF'"
58		fi
59	fi
60
61	OK=0
62	for WHITE in $WHITELIST
63	do
64		if [ "$UNDEF" = "$WHITE" ]; then
65			OK=1
66			break
67		fi
68	done
69
70	# ignore register save/restore funcitons
71	case $UNDEF in
72	_restgpr_*|_restgpr0_*|_rest32gpr_*)
73		OK=1
74		;;
75	_savegpr_*|_savegpr0_*|_save32gpr_*)
76		OK=1
77		;;
78	esac
79
80	if [ $OK -eq 0 ]; then
81		ERROR=1
82		echo "Error: External symbol '$UNDEF' referenced" \
83		     "from prom_init.c" >&2
84	fi
85done
86
87check_section $OBJ .data
88check_section $OBJ .bss
89check_section $OBJ .init.data
90
91exit $ERROR

 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
24__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
 
25
26NM="$1"
27OBJ="$2"
28
29ERROR=0
30
 
 
 
 
 
 
 
 
 
 
 
 
31for UNDEF in $($NM -u $OBJ | awk '{print $2}')
32do
33	# On 64-bit nm gives us the function descriptors, which have
34	# a leading . on the name, so strip it off here.
35	UNDEF="${UNDEF#.}"
36
37	if [ $KBUILD_VERBOSE ]; then
38		if [ $KBUILD_VERBOSE -ne 0 ]; then
39			echo "Checking prom_init.o symbol '$UNDEF'"
40		fi
41	fi
42
43	OK=0
44	for WHITE in $WHITELIST
45	do
46		if [ "$UNDEF" = "$WHITE" ]; then
47			OK=1
48			break
49		fi
50	done
51
52	# ignore register save/restore funcitons
53	case $UNDEF in
54	_restgpr_*|_restgpr0_*|_rest32gpr_*)
55		OK=1
56		;;
57	_savegpr_*|_savegpr0_*|_save32gpr_*)
58		OK=1
59		;;
60	esac
61
62	if [ $OK -eq 0 ]; then
63		ERROR=1
64		echo "Error: External symbol '$UNDEF' referenced" \
65		     "from prom_init.c" >&2
66	fi
67done
 
 
 
 
68
69exit $ERROR