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." 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 91