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# 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$" ${KCONFIG_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
29btext_setup_display TOC. relocate"
 
30
31NM="$1"
32OBJ="$2"
33
34ERROR=0
35
36check_section()
37{
38    file=$1
39    section=$2
40    size=$(objdump -h -j $section $file 2>/dev/null | awk "\$2 == \"$section\" {print \$3}")
41    size=${size:-0}
42    if [ $size -ne 0 ]; then
43	ERROR=1
44	echo "Error: Section $section not empty in prom_init.c" >&2
45    fi
46}
47
48for UNDEF in $($NM -u $OBJ | awk '{print $2}')
49do
50	# On 64-bit nm gives us the function descriptors, which have
51	# a leading . on the name, so strip it off here.
52	UNDEF="${UNDEF#.}"
53
54	if [ $KBUILD_VERBOSE ]; then
55		if [ $KBUILD_VERBOSE -ne 0 ]; then
56			echo "Checking prom_init.o symbol '$UNDEF'"
57		fi
58	fi
59
60	OK=0
61	for WHITE in $WHITELIST
62	do
63		if [ "$UNDEF" = "$WHITE" ]; then
64			OK=1
65			break
66		fi
67	done
68
69	# ignore register save/restore funcitons
70	case $UNDEF in
71	_restgpr_*|_restgpr0_*|_rest32gpr_*)
72		OK=1
73		;;
74	_savegpr_*|_savegpr0_*|_save32gpr_*)
75		OK=1
76		;;
77	esac
78
79	if [ $OK -eq 0 ]; then
80		ERROR=1
81		echo "Error: External symbol '$UNDEF' referenced" \
82		     "from prom_init.c" >&2
83	fi
84done
85
86check_section $OBJ .data
87check_section $OBJ .bss
88check_section $OBJ .init.data
89
90exit $ERROR