linux_dsm_epyc7002/arch/powerpc/kernel/prom_init_check.sh
Christophe Leroy 450e7dd400 powerpc/prom_init: don't use string functions from lib/
When KASAN is active, the string functions in lib/ are doing the
KASAN checks. This is too early for prom_init.

This patch implements dedicated string functions for prom_init,
which will be compiled in with KASAN disabled.

Size of prom_init before the patch:
   text	   data	    bss	    dec	    hex	filename
  12060	    488	   6960	  19508	   4c34	arch/powerpc/kernel/prom_init.o

Size of prom_init after the patch:
   text	   data	    bss	    dec	    hex	filename
  12460	    488	   6960	  19908	   4dc4	arch/powerpc/kernel/prom_init.o

This increases the size of prom_init a bit, but as prom_init is
in __init section, it is freed after boot anyway.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03 01:20:25 +10:00

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#!/bin/sh
#
# Copyright © 2008 IBM Corporation
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version
# 2 of the License, or (at your option) any later version.
# 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$" .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
reloc_got2 kernstart_addr memstart_addr linux_banner _stext
__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
NM="$1"
OBJ="$2"
ERROR=0
function 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#.}"
if [ $KBUILD_VERBOSE ]; then
if [ $KBUILD_VERBOSE -ne 0 ]; then
echo "Checking prom_init.o symbol '$UNDEF'"
fi
fi
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