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 95