| #!/bin/sh |
| # SPDX-License-Identifier: GPL-2.0-or-later |
| # |
| # Copyright © 2008 IBM Corporation |
| # |
| |
| # This script checks prom_init.o to see what external symbols it |
| # is using, if it finds symbols not in the whitelist it returns |
| # an error. The point of this is to discourage people from |
| # intentionally or accidentally adding new code to prom_init.c |
| # which has side effects on other parts of the kernel. |
| |
| # If you really need to reference something from prom_init.o add |
| # it to the list below: |
| |
| grep "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} >/dev/null |
| if [ $? -eq 0 ] |
| then |
| MEM_FUNCS="__memcpy __memset" |
| else |
| MEM_FUNCS="memcpy memset" |
| fi |
| |
| WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush |
| _end enter_prom $MEM_FUNCS reloc_offset __secondary_hold |
| __secondary_hold_acknowledge __secondary_hold_spinloop __start |
| logo_linux_clut224 btext_prepare_BAT |
| reloc_got2 kernstart_addr memstart_addr linux_banner _stext |
| btext_setup_display TOC. relocate" |
| |
| NM="$1" |
| OBJ="$2" |
| |
| ERROR=0 |
| |
| check_section() |
| { |
| file=$1 |
| section=$2 |
| size=$(objdump -h -j $section $file 2>/dev/null | awk "\$2 == \"$section\" {print \$3}") |
| size=${size:-0} |
| if [ $size -ne 0 ]; then |
| ERROR=1 |
| echo "Error: Section $section not empty in prom_init.c" >&2 |
| fi |
| } |
| |
| for UNDEF in $($NM -u $OBJ | awk '{print $2}') |
| do |
| # On 64-bit nm gives us the function descriptors, which have |
| # a leading . on the name, so strip it off here. |
| UNDEF="${UNDEF#.}" |
| |
| case "$KBUILD_VERBOSE" in |
| *1*) |
| echo "Checking prom_init.o symbol '$UNDEF'" ;; |
| esac |
| |
| OK=0 |
| for WHITE in $WHITELIST |
| do |
| if [ "$UNDEF" = "$WHITE" ]; then |
| OK=1 |
| break |
| fi |
| done |
| |
| # ignore register save/restore funcitons |
| case $UNDEF in |
| _restgpr_*|_restgpr0_*|_rest32gpr_*) |
| OK=1 |
| ;; |
| _savegpr_*|_savegpr0_*|_save32gpr_*) |
| OK=1 |
| ;; |
| esac |
| |
| if [ $OK -eq 0 ]; then |
| ERROR=1 |
| echo "Error: External symbol '$UNDEF' referenced" \ |
| "from prom_init.c" >&2 |
| fi |
| done |
| |
| check_section $OBJ .data |
| check_section $OBJ .bss |
| check_section $OBJ .init.data |
| |
| exit $ERROR |