linux/arch/powerpc/kernel/prom_init_check.sh
Kumar Gala da3de6df33 [POWERPC] Fix -Os kernel builds with newer gcc versions
GCC 4.4.x looks to be adding support for generating out-of-line register
saves/restores based on:

http://gcc.gnu.org/ml/gcc-patches/2008-04/msg01678.html

This breaks the kernel if we enable CONFIG_CC_OPTIMIZE_FOR_SIZE.  To fix
this we add the use the save/restore code from gcc and simplified it down
for our needs (integer only).

Additionally, we have to link this code into each module.  The other
solution was to add EXPORT_SYMBOL() which meant going through the
trampoline which seemed nonsensical for these out-of-line routines.

Finally, we add some checks to prom_init_check.sh to ignore the
out-of-line save/restore functions.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-16 15:00:54 +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:
WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
_end enter_prom memcpy memset reloc_offset __secondary_hold
__secondary_hold_acknowledge __secondary_hold_spinloop __start
strcmp strcpy strlcpy strlen strncmp strstr logo_linux_clut224
reloc_got2 kernstart_addr"
NM="$1"
OBJ="$2"
ERROR=0
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" = "$WHITE" ]; then
OK=1
break
fi
done
# ignore register save/restore funcitons
if [ "${UNDEF:0:9}" = "_restgpr_" ]; then
OK=1
fi
if [ "${UNDEF:0:11}" = "_rest32gpr_" ]; then
OK=1
fi
if [ "${UNDEF:0:9}" = "_savegpr_" ]; then
OK=1
fi
if [ "${UNDEF:0:11}" = "_save32gpr_" ]; then
OK=1
fi
if [ $OK -eq 0 ]; then
ERROR=1
echo "Error: External symbol '$UNDEF' referenced" \
"from prom_init.c" >&2
fi
done
exit $ERROR