xref: /openbmc/linux/scripts/decodecode (revision b1c3d2be) 
1#!/bin/bash
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# PC=hex - the PC (program counter) the oops points to
10
11faultlinenum=1
12
13cleanup() {
14	rm -f $T $T.s $T.o $T.oo $T.aa $T.dis
15	exit 1
16}
17
18die() {
19	echo "$@"
20	exit 1
21}
22
23trap cleanup EXIT
24
25T=`mktemp` || die "cannot create temp file"
26code=
27cont=
28
29while read i ; do
30
31case "$i" in
32*Code:*)
33	code=$i
34	cont=yes
35	;;
36*)
37	[ -n "$cont" ] && {
38		xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')"
39		if [ -n "$xdump" ]; then
40			code="$code $xdump"
41		else
42			cont=
43		fi
44	}
45	;;
46esac
47
48done
49
50if [ -z "$code" ]; then
51	rm $T
52	exit
53fi
54
55echo $code
56code=`echo $code | sed -e 's/.*Code: //'`
57
58width=`expr index "$code" ' '`
59width=$((($width-1)/2))
60case $width in
611) type=byte ;;
622) type=2byte ;;
634) type=4byte ;;
64esac
65
66if [ -z "$ARCH" ]; then
67    case `uname -m` in
68	aarch64*) ARCH=arm64 ;;
69	arm*) ARCH=arm ;;
70    esac
71fi
72
73# Params: (tmp_file, pc_sub)
74disas() {
75	t=$1
76	pc_sub=$2
77
78	${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1
79
80	if [ "$ARCH" = "arm" ]; then
81		if [ $width -eq 2 ]; then
82			OBJDUMPFLAGS="-M force-thumb"
83		fi
84
85		${CROSS_COMPILE}strip $t.o
86	fi
87
88	if [ "$ARCH" = "arm64" ]; then
89		if [ $width -eq 4 ]; then
90			type=inst
91		fi
92
93		${CROSS_COMPILE}strip $t.o
94	fi
95
96	if [ $pc_sub -ne 0 ]; then
97		if [ $PC ]; then
98			adj_vma=$(( $PC - $pc_sub ))
99			OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma"
100		fi
101	fi
102
103	${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \
104		grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1
105}
106
107# Match the maximum number of opcode bytes from @op_bytes contained within
108# @opline
109#
110# Params:
111# @op_bytes: The string of bytes from the Code: line
112# @opline: The disassembled line coming from objdump
113#
114# Returns:
115# The max number of opcode bytes from the beginning of @op_bytes which match
116# the opcode bytes in the objdump line.
117get_substr_opcode_bytes_num()
118{
119	local op_bytes=$1
120	local opline=$2
121
122	local retval=0
123	substr=""
124
125	for opc in $op_bytes;
126	do
127		substr+="$opc"
128
129		# return if opcode bytes do not match @opline anymore
130		if ! echo $opline | grep -q "$substr";
131		then
132			break
133		fi
134
135		# add trailing space
136		substr+=" "
137		retval=$((retval+1))
138	done
139
140	return $retval
141}
142
143# Return the line number in objdump output to where the IP marker in the Code:
144# line points to
145#
146# Params:
147# @all_code: code in bytes without the marker
148# @dis_file: disassembled file
149# @ip_byte: The byte to which the IP points to
150get_faultlinenum()
151{
152	local all_code="$1"
153	local dis_file="$2"
154
155	# num bytes including IP byte
156	local num_bytes_ip=$(( $3 + 1 * $width ))
157
158	# Add the two header lines (we're counting from 1).
159	local retval=3
160
161	# remove marker
162	all_code=$(echo $all_code | sed -e 's/[<>()]//g')
163
164	while read line
165	do
166		get_substr_opcode_bytes_num "$all_code" "$line"
167		ate_opcodes=$?
168
169		if ! (( $ate_opcodes )); then
170			continue
171		fi
172
173		num_bytes_ip=$((num_bytes_ip - ($ate_opcodes * $width) ))
174		if (( $num_bytes_ip <= 0 )); then
175			break
176		fi
177
178		# Delete matched opcode bytes from all_code. For that, compute
179		# how many chars those opcodes are represented by and include
180		# trailing space.
181		#
182		# a byte is 2 chars, ate_opcodes is also the number of trailing
183		# spaces
184		del_chars=$(( ($ate_opcodes * $width * 2) + $ate_opcodes ))
185
186		all_code=$(echo $all_code | sed -e "s!^.\{$del_chars\}!!")
187
188		let "retval+=1"
189
190	done < $dis_file
191
192	return $retval
193}
194
195marker=`expr index "$code" "\<"`
196if [ $marker -eq 0 ]; then
197	marker=`expr index "$code" "\("`
198fi
199
200touch $T.oo
201if [ $marker -ne 0 ]; then
202	# How many bytes to subtract from the program counter
203	# in order to get to the beginning virtual address of the
204	# Code:
205	pc_sub=$(( (($marker - 1) / (2 * $width + 1)) * $width ))
206	echo All code >> $T.oo
207	echo ======== >> $T.oo
208	beforemark=`echo "$code"`
209	echo -n "	.$type 0x" > $T.s
210
211	echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s
212
213	disas $T $pc_sub
214
215	cat $T.dis >> $T.oo
216
217	get_faultlinenum "$code" "$T.dis" $pc_sub
218	faultlinenum=$?
219
220	# and fix code at-and-after marker
221	code=`echo "$code" | cut -c$((${marker} + 1))-`
222
223	rm -f $T.o $T.s $T.dis
224fi
225
226echo Code starting with the faulting instruction  > $T.aa
227echo =========================================== >> $T.aa
228code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
229echo -n "	.$type 0x" > $T.s
230echo $code >> $T.s
231disas $T 0
232cat $T.dis >> $T.aa
233
234cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
235echo
236cat $T.aa
237cleanup
238