aboutsummaryrefslogtreecommitdiff
path: root/scripts/decodecode
blob: 8fe71c29238179095adb3f884049991e77be91c6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
# Disassemble the Code: line in Linux oopses
# usage: decodecode < oops.file
#
# options: set env. variable AFLAGS=options to pass options to "as";
# e.g., to decode an i386 oops on an x86_64 system, use:
# AFLAGS=--32 decodecode < 386.oops
# PC=hex - the PC (program counter) the oops points to

faultlinenum=1

cleanup() {
	rm -f $T $T.s $T.o $T.oo $T.aa $T.dis
	exit 1
}

die() {
	echo "$@"
	exit 1
}

trap cleanup EXIT

T=`mktemp` || die "cannot create temp file"
code=
cont=

while read i ; do

case "$i" in
*Code:*)
	code=$i
	cont=yes
	;;
*)
	[ -n "$cont" ] && {
		xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')"
		if [ -n "$xdump" ]; then
			code="$code $xdump"
		else
			cont=
		fi
	}
	;;
esac

done

if [ -z "$code" ]; then
	rm $T
	exit
fi

echo $code
code=`echo $code | sed -e 's/.*Code: //'`

width=`expr index "$code" ' '`
width=$((($width-1)/2))
case $width in
1) type=byte ;;
2) type=2byte ;;
4) type=4byte ;;
esac

if [ -z "$ARCH" ]; then
    case `uname -m` in
	aarch64*) ARCH=arm64 ;;
	arm*) ARCH=arm ;;
    esac
fi

# Params: (tmp_file, pc_sub)
disas() {
	t=$1
	pc_sub=$2

	${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1

	if [ "$ARCH" = "arm" ]; then
		if [ $width -eq 2 ]; then
			OBJDUMPFLAGS="-M force-thumb"
		fi

		${CROSS_COMPILE}strip $t.o
	fi

	if [ "$ARCH" = "arm64" ]; then
		if [ $width -eq 4 ]; then
			type=inst
		fi

		${CROSS_COMPILE}strip $t.o
	fi

	if [ "$ARCH" = "riscv" ]; then
		OBJDUMPFLAGS="-M no-aliases --section=.text -D"
		${CROSS_COMPILE}strip $t.o
	fi

	if [ $pc_sub -ne 0 ]; then
		if [ $PC ]; then
			adj_vma=$(( $PC - $pc_sub ))
			OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma"
		fi
	fi

	${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \
		grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1
}

# Match the maximum number of opcode bytes from @op_bytes contained within
# @opline
#
# Params:
# @op_bytes: The string of bytes from the Code: line
# @opline: The disassembled line coming from objdump
#
# Returns:
# The max number of opcode bytes from the beginning of @op_bytes which match
# the opcode bytes in the objdump line.
get_substr_opcode_bytes_num()
{
	local op_bytes=$1
	local opline=$2

	local retval=0
	substr=""

	for opc in $op_bytes;
	do
		substr+="$opc"

		opcode="$substr"
		if [ "$ARCH" = "riscv" ]; then
			opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
		fi

		# return if opcode bytes do not match @opline anymore
		if ! echo $opline | grep -q "$opcode";
		then
			break
		fi

		# add trailing space
		substr+=" "
		retval=$((retval+1))
	done

	return $retval
}

# Return the line number in objdump output to where the IP marker in the Code:
# line points to
#
# Params:
# @all_code: code in bytes without the marker
# @dis_file: disassembled file
# @ip_byte: The byte to which the IP points to
get_faultlinenum()
{
	local all_code="$1"
	local dis_file="$2"

	# num bytes including IP byte
	local num_bytes_ip=$(( $3 + 1 * $width ))

	# Add the two header lines (we're counting from 1).
	local retval=3

	# remove marker
	all_code=$(echo $all_code | sed -e 's/[<>()]//g')

	while read line
	do
		get_substr_opcode_bytes_num "$all_code" "$line"
		ate_opcodes=$?

		if ! (( $ate_opcodes )); then
			continue
		fi

		num_bytes_ip=$((num_bytes_ip - ($ate_opcodes * $width) ))
		if (( $num_bytes_ip <= 0 )); then
			break
		fi

		# Delete matched opcode bytes from all_code. For that, compute
		# how many chars those opcodes are represented by and include
		# trailing space.
		#
		# a byte is 2 chars, ate_opcodes is also the number of trailing
		# spaces
		del_chars=$(( ($ate_opcodes * $width * 2) + $ate_opcodes ))

		all_code=$(echo $all_code | sed -e "s!^.\{$del_chars\}!!")

		let "retval+=1"

	done < $dis_file

	return $retval
}

marker=`expr index "$code" "\<"`
if [ $marker -eq 0 ]; then
	marker=`expr index "$code" "\("`
fi

touch $T.oo
if [ $marker -ne 0 ]; then
	# How many bytes to subtract from the program counter
	# in order to get to the beginning virtual address of the
	# Code:
	pc_sub=$(( (($marker - 1) / (2 * $width + 1)) * $width ))
	echo All code >> $T.oo
	echo ======== >> $T.oo
	beforemark=`echo "$code"`
	echo -n "	.$type 0x" > $T.s

	echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s

	disas $T $pc_sub

	cat $T.dis >> $T.oo

	get_faultlinenum "$code" "$T.dis" $pc_sub
	faultlinenum=$?

	# and fix code at-and-after marker
	code=`echo "$code" | cut -c$((${marker} + 1))-`

	rm -f $T.o $T.s $T.dis
fi

echo Code starting with the faulting instruction  > $T.aa
echo =========================================== >> $T.aa
code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
echo -n "	.$type 0x" > $T.s
echo $code >> $T.s
disas $T 0
cat $T.dis >> $T.aa

cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
echo
cat $T.aa
cleanup