projects/linux·blob master · refs

94 lines · 2.1 KiB

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