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
16has_renamed_memintrinsics()
17{
18	grep -q "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} && \
19		! grep -q "^CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y" ${KCONFIG_CONFIG}
20}
21
22if has_renamed_memintrinsics
23then
24	MEM_FUNCS="__memcpy __memset"
25else
26	MEM_FUNCS="memcpy memset"
27fi
28
29WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
30_end enter_prom $MEM_FUNCS reloc_offset __secondary_hold
31__secondary_hold_acknowledge __secondary_hold_spinloop __start
32logo_linux_clut224 btext_prepare_BAT
33reloc_got2 kernstart_addr memstart_addr linux_banner _stext
34btext_setup_display TOC. relocate"
 
35
36NM="$1"
37OBJ="$2"
38
39ERROR=0
40
41check_section()
42{
43    file=$1
44    section=$2
45    size=$(objdump -h -j $section $file 2>/dev/null | awk "\$2 == \"$section\" {print \$3}")
46    size=${size:-0}
47    if [ $size -ne 0 ]; then
48	ERROR=1
49	echo "Error: Section $section not empty in prom_init.c" >&2
50    fi
51}
52
53for UNDEF in $($NM -u $OBJ | awk '{print $2}')
54do
55	# On 64-bit nm gives us the function descriptors, which have
56	# a leading . on the name, so strip it off here.
57	UNDEF="${UNDEF#.}"
58
59	case "$KBUILD_VERBOSE" in
60	*1*)
61		echo "Checking prom_init.o symbol '$UNDEF'" ;;
62	esac
 
63
64	OK=0
65	for WHITE in $WHITELIST
66	do
67		if [ "$UNDEF" = "$WHITE" ]; then
68			OK=1
69			break
70		fi
71	done
72
73	# ignore register save/restore funcitons
74	case $UNDEF in
75	_restgpr_*|_restgpr0_*|_rest32gpr_*)
76		OK=1
77		;;
78	_savegpr_*|_savegpr0_*|_save32gpr_*)
79		OK=1
80		;;
81	esac
82
83	if [ $OK -eq 0 ]; then
84		ERROR=1
85		echo "Error: External symbol '$UNDEF' referenced" \
86		     "from prom_init.c" >&2
87	fi
88done
89
90check_section $OBJ .data
91check_section $OBJ .bss
92check_section $OBJ .init.data
93
94exit $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$" .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