xref: /openbmc/linux/scripts/decodecode (revision 0526b56c) 
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 $t.o
94	fi
95
96	if [ "$ARCH" = "riscv" ]; then
97		OBJDUMPFLAGS="-M no-aliases --section=.text -D"
98		${CROSS_COMPILE}strip $t.o
99	fi
100
101	if [ $pc_sub -ne 0 ]; then
102		if [ $PC ]; then
103			adj_vma=$(( $PC - $pc_sub ))
104			OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma"
105		fi
106	fi
107
108	${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \
109		grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1
110}
111
112# Match the maximum number of opcode bytes from @op_bytes contained within
113# @opline
114#
115# Params:
116# @op_bytes: The string of bytes from the Code: line
117# @opline: The disassembled line coming from objdump
118#
119# Returns:
120# The max number of opcode bytes from the beginning of @op_bytes which match
121# the opcode bytes in the objdump line.
122get_substr_opcode_bytes_num()
123{
124	local op_bytes=$1
125	local opline=$2
126
127	local retval=0
128	substr=""
129
130	for opc in $op_bytes;
131	do
132		substr+="$opc"
133
134		opcode="$substr"
135		if [ "$ARCH" = "riscv" ]; then
136			opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
137		fi
138
139		# return if opcode bytes do not match @opline anymore
140		if ! echo $opline | grep -q "$opcode";
141		then
142			break
143		fi
144
145		# add trailing space
146		substr+=" "
147		retval=$((retval+1))
148	done
149
150	return $retval
151}
152
153# Return the line number in objdump output to where the IP marker in the Code:
154# line points to
155#
156# Params:
157# @all_code: code in bytes without the marker
158# @dis_file: disassembled file
159# @ip_byte: The byte to which the IP points to
160get_faultlinenum()
161{
162	local all_code="$1"
163	local dis_file="$2"
164
165	# num bytes including IP byte
166	local num_bytes_ip=$(( $3 + 1 * $width ))
167
168	# Add the two header lines (we're counting from 1).
169	local retval=3
170
171	# remove marker
172	all_code=$(echo $all_code | sed -e 's/[<>()]//g')
173
174	while read line
175	do
176		get_substr_opcode_bytes_num "$all_code" "$line"
177		ate_opcodes=$?
178
179		if ! (( $ate_opcodes )); then
180			continue
181		fi
182
183		num_bytes_ip=$((num_bytes_ip - ($ate_opcodes * $width) ))
184		if (( $num_bytes_ip <= 0 )); then
185			break
186		fi
187
188		# Delete matched opcode bytes from all_code. For that, compute
189		# how many chars those opcodes are represented by and include
190		# trailing space.
191		#
192		# a byte is 2 chars, ate_opcodes is also the number of trailing
193		# spaces
194		del_chars=$(( ($ate_opcodes * $width * 2) + $ate_opcodes ))
195
196		all_code=$(echo $all_code | sed -e "s!^.\{$del_chars\}!!")
197
198		let "retval+=1"
199
200	done < $dis_file
201
202	return $retval
203}
204
205marker=`expr index "$code" "\<"`
206if [ $marker -eq 0 ]; then
207	marker=`expr index "$code" "\("`
208fi
209
210touch $T.oo
211if [ $marker -ne 0 ]; then
212	# How many bytes to subtract from the program counter
213	# in order to get to the beginning virtual address of the
214	# Code:
215	pc_sub=$(( (($marker - 1) / (2 * $width + 1)) * $width ))
216	echo All code >> $T.oo
217	echo ======== >> $T.oo
218	beforemark=`echo "$code"`
219	echo -n "	.$type 0x" > $T.s
220
221	echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s
222
223	disas $T $pc_sub
224
225	cat $T.dis >> $T.oo
226
227	get_faultlinenum "$code" "$T.dis" $pc_sub
228	faultlinenum=$?
229
230	# and fix code at-and-after marker
231	code=`echo "$code" | cut -c$((${marker} + 1))-`
232
233	rm -f $T.o $T.s $T.dis
234fi
235
236echo Code starting with the faulting instruction  > $T.aa
237echo =========================================== >> $T.aa
238code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
239echo -n "	.$type 0x" > $T.s
240echo $code >> $T.s
241disas $T 0
242cat $T.dis >> $T.aa
243
244cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
245echo
246cat $T.aa
247cleanup
248