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
11 faultlinenum=1
12
13 cleanup() {
14 rm -f $T $T.s $T.o $T.oo $T.aa $T.dis
15 exit 1
16 }
17
18 die() {
19 echo "$@"
20 exit 1
21 }
22
23 trap cleanup EXIT
24
25 T=`mktemp` || die "cannot create temp file"
26 code=
27 cont=
28
29 while read i ; do
30
31 case "$i" in
32 *Code:*)
33 code=$i
34 cont=yes
35 ;;
36 *)
37 [ -n "$cont" ] && {
38 xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')"
39 if [ -n "$xdump" ]; then
40 code="$code $xdump"
41 else
42 cont=
43 fi
44 }
45 ;;
46 esac
47
48 done
49
50 if [ -z "$code" ]; then
51 rm $T
52 exit
53 fi
54
55 echo $code
56 code=`echo $code | sed -e 's/.*Code: //'`
57
58 width=`expr index "$code" ' '`
59 width=$((($width-1)/2))
60 case $width in
61 1) type=byte ;;
62 2) type=2byte ;;
63 4) type=4byte ;;
64 esac
65
66 if [ -z "$ARCH" ]; then
67 case `uname -m` in
68 aarch64*) ARCH=arm64 ;;
69 arm*) ARCH=arm ;;
70 loongarch*) ARCH=loongarch ;;
71 esac
72 fi
73
74 # Params: (tmp_file, pc_sub)
75 disas() {
76 t=$1
77 pc_sub=$2
78
79 ${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1
80
81 if [ "$ARCH" = "arm" ]; then
82 if [ $width -eq 2 ]; then
83 OBJDUMPFLAGS="-M force-thumb"
84 fi
85
86 ${CROSS_COMPILE}strip $t.o
87 fi
88
89 if [ "$ARCH" = "arm64" ]; then
90 if [ $width -eq 4 ]; then
91 type=inst
92 fi
93
94 ${CROSS_COMPILE}strip $t.o
95 fi
96
97 if [ "$ARCH" = "riscv" ]; then
98 OBJDUMPFLAGS="-M no-aliases --section=.text -D"
99 ${CROSS_COMPILE}strip $t.o
100 fi
101
102 if [ "$ARCH" = "loongarch" ]; then
103 ${CROSS_COMPILE}strip $t.o
104 fi
105
106 if [ $pc_sub -ne 0 ]; then
107 if [ $PC ]; then
108 adj_vma=$(( $PC - $pc_sub ))
109 OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma"
110 fi
111 fi
112
113 ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \
114 grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1
115 }
116
117 # Match the maximum number of opcode bytes from @op_bytes contained within
118 # @opline
119 #
120 # Params:
121 # @op_bytes: The string of bytes from the Code: line
122 # @opline: The disassembled line coming from objdump
123 #
124 # Returns:
125 # The max number of opcode bytes from the beginning of @op_bytes which match
126 # the opcode bytes in the objdump line.
127 get_substr_opcode_bytes_num()
128 {
129 local op_bytes=$1
130 local opline=$2
131
132 local retval=0
133 substr=""
134
135 for opc in $op_bytes;
136 do
137 substr+="$opc"
138
139 opcode="$substr"
140 if [ "$ARCH" = "riscv" ]; then
141 opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
142 fi
143
144 # return if opcode bytes do not match @opline anymore
145 if ! echo $opline | grep -q "$opcode";
146 then
147 break
148 fi
149
150 # add trailing space
151 substr+=" "
152 retval=$((retval+1))
153 done
154
155 return $retval
156 }
157
158 # Return the line number in objdump output to where the IP marker in the Code:
159 # line points to
160 #
161 # Params:
162 # @all_code: code in bytes without the marker
163 # @dis_file: disassembled file
164 # @ip_byte: The byte to which the IP points to
165 get_faultlinenum()
166 {
167 local all_code="$1"
168 local dis_file="$2"
169
170 # num bytes including IP byte
171 local num_bytes_ip=$(( $3 + 1 * $width ))
172
173 # Add the two header lines (we're counting from 1).
174 local retval=3
175
176 # remove marker
177 all_code=$(echo $all_code | sed -e 's/[<>()]//g')
178
179 while read line
180 do
181 get_substr_opcode_bytes_num "$all_code" "$line"
182 ate_opcodes=$?
183
184 if ! (( $ate_opcodes )); then
185 continue
186 fi
187
188 num_bytes_ip=$((num_bytes_ip - ($ate_opcodes * $width) ))
189 if (( $num_bytes_ip <= 0 )); then
190 break
191 fi
192
193 # Delete matched opcode bytes from all_code. For that, compute
194 # how many chars those opcodes are represented by and include
195 # trailing space.
196 #
197 # a byte is 2 chars, ate_opcodes is also the number of trailing
198 # spaces
199 del_chars=$(( ($ate_opcodes * $width * 2) + $ate_opcodes ))
200
201 all_code=$(echo $all_code | sed -e "s!^.\{$del_chars\}!!")
202
203 let "retval+=1"
204
205 done < $dis_file
206
207 return $retval
208 }
209
210 marker=`expr index "$code" "\<"`
211 if [ $marker -eq 0 ]; then
212 marker=`expr index "$code" "\("`
213 fi
214
215 touch $T.oo
216 if [ $marker -ne 0 ]; then
217 # How many bytes to subtract from the program counter
218 # in order to get to the beginning virtual address of the
219 # Code:
220 pc_sub=$(( (($marker - 1) / (2 * $width + 1)) * $width ))
221 echo All code >> $T.oo
222 echo ======== >> $T.oo
223 beforemark=`echo "$code"`
224 echo -n " .$type 0x" > $T.s
225
226 echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s
227
228 disas $T $pc_sub
229
230 cat $T.dis >> $T.oo
231
232 get_faultlinenum "$code" "$T.dis" $pc_sub
233 faultlinenum=$?
234
235 # and fix code at-and-after marker
236 code=`echo "$code" | cut -c$((${marker} + 1))-`
237
238 rm -f $T.o $T.s $T.dis
239 fi
240
241 echo Code starting with the faulting instruction > $T.aa
242 echo =========================================== >> $T.aa
243 code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
244 echo -n " .$type 0x" > $T.s
245 echo $code >> $T.s
246 disas $T 0
247 cat $T.dis >> $T.aa
248
249 cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
250 echo
251 cat $T.aa
252 cleanup
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