unrel_branch_check.sh

# Copyright © 2016 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 the relocations of a vmlinux for "suspicious"
# branches from unrelocated code (head_64.S code).

# Turn this on if you want more debug output:
# set -x

# Have Kbuild supply the path to objdump so we handle cross compilation.
objdump="$1"
vmlinux="$2"

#__end_interrupts should be located within the first 64K

end_intr=0x$(
"$objdump" -R "$vmlinux" -d --start-address=0xc000000000000000		\
		 --stop-address=0xc000000000010000 |
grep '\<__end_interrupts>:' |
awk '{print $1}'
)

BRANCHES=$(
"$objdump" -R "$vmlinux" -D --start-address=0xc000000000000000		\
		--stop-address=${end_intr} |
grep -e "^c[0-9a-f]*:[[:space:]]*\([0-9a-f][0-9a-f][[:space:]]\)\{4\}[[:space:]]*b" |
grep -v '\<__start_initialization_multiplatform>' |
grep -v -e 'b.\?.\?ctr' |
grep -v -e 'b.\?.\?lr' |
sed 's/://' |
awk '{ print $1 ":" $6 ":0x" $7 ":" $8 " "}'
)

for tuple in $BRANCHES
do
	from=`echo $tuple | cut -d':' -f1`
	branch=`echo $tuple | cut -d':' -f2`
	to=`echo $tuple | cut -d':' -f3 | sed 's/cr[0-7],//'`
	sym=`echo $tuple | cut -d':' -f4`

	if (( $to > $end_intr ))
	then
		if [ -z "$bad_branches" ]; then
			echo "WARNING: Unrelocated relative branches"
			bad_branches="yes"
		fi
		echo "$from $branch-> $to $sym"
	fi
done

if [ -z "$bad_branches" ]; then
	exit 0
fi