1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0
3# Disassemble the Code: line in Linux oopses
4# usage: decodecode < oops.file
5#
6# options: set env. variable AFLAGS=options to pass options to "as";
7# e.g., to decode an i386 oops on an x86_64 system, use:
8# AFLAGS=--32 decodecode < 386.oops
9
10cleanup() {
11	rm -f $T $T.s $T.o $T.oo $T.aa $T.dis
12	exit 1
13}
14
15die() {
16	echo "$@"
17	exit 1
18}
19
20trap cleanup EXIT
21
22T=`mktemp` || die "cannot create temp file"
23code=
24cont=
25
26while read i ; do
27
28case "$i" in
29*Code:*)
30	code=$i
31	cont=yes
32	;;
33*)
34	[ -n "$cont" ] && {
35		xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')"
36		if [ -n "$xdump" ]; then
37			code="$code $xdump"
38		else
39			cont=
40		fi
41	}
42	;;
43esac
44
45done
46
47if [ -z "$code" ]; then
48	rm $T
49	exit
50fi
51
52echo $code
53code=`echo $code | sed -e 's/.*Code: //'`
54
55width=`expr index "$code" ' '`
56width=$((($width-1)/2))
57case $width in
581) type=byte ;;
592) type=2byte ;;
604) type=4byte ;;
61esac
62
63if [ -z "$ARCH" ]; then
64    case `uname -m` in
65	aarch64*) ARCH=arm64 ;;
66	arm*) ARCH=arm ;;
67    esac
68fi
69
70disas() {
71	${CROSS_COMPILE}as $AFLAGS -o $1.o $1.s > /dev/null 2>&1
72
73	if [ "$ARCH" = "arm" ]; then
74		if [ $width -eq 2 ]; then
75			OBJDUMPFLAGS="-M force-thumb"
76		fi
77
78		${CROSS_COMPILE}strip $1.o
79	fi
80
81	if [ "$ARCH" = "arm64" ]; then
82		if [ $width -eq 4 ]; then
83			type=inst
84		fi
85
86		${CROSS_COMPILE}strip $1.o
87	fi
88
89	${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \
90		grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1
91}
92
93marker=`expr index "$code" "\<"`
94if [ $marker -eq 0 ]; then
95	marker=`expr index "$code" "\("`
96fi
97
98touch $T.oo
99if [ $marker -ne 0 ]; then
100	echo All code >> $T.oo
101	echo ======== >> $T.oo
102	beforemark=`echo "$code"`
103	echo -n "	.$type 0x" > $T.s
104	echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s
105	disas $T
106	cat $T.dis >> $T.oo
107	rm -f $T.o $T.s $T.dis
108
109# and fix code at-and-after marker
110	code=`echo "$code" | cut -c$((${marker} + 1))-`
111fi
112echo Code starting with the faulting instruction  > $T.aa
113echo =========================================== >> $T.aa
114code=`echo $code | sed -e 's/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
115echo -n "	.$type 0x" > $T.s
116echo $code >> $T.s
117disas $T
118cat $T.dis >> $T.aa
119
120# (lines of whole $T.oo) - (lines of $T.aa, i.e. "Code starting") + 3,
121# i.e. the title + the "===..=" line (sed is counting from 1, 0 address is
122# special)
123faultlinenum=$(( $(wc -l $T.oo  | cut -d" " -f1) - \
124		 $(wc -l $T.aa  | cut -d" " -f1) + 3))
125
126faultline=`cat $T.dis | head -1 | cut -d":" -f2-`
127faultline=`echo "$faultline" | sed -e 's/\[/\\\[/g; s/\]/\\\]/g'`
128
129cat $T.oo | sed -e "${faultlinenum}s/^\(.*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
130echo
131cat $T.aa
132cleanup
133