scripts/decodecode

   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     esac
  71 fi
  72
  73 # Params: (tmp_file, pc_sub)
  74 disas() {
  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.
 122 get_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
 160 get_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 $retval
 203 }
 204
 205 marker=`expr index "$code" "\<"`
 206 if [ $marker -eq 0 ]; then
 207         marker=`expr index "$code" "\("`
 208 fi
 209
 210 touch $T.oo
 211 if [ $marker -ne 0 ]; then
 212         # How many bytes to subtract from the program counter
 213         # in order to get to the beginning virtual address of the
 214         # Code:
 215         pc_sub=$(( (($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
 234 fi
 235
 236 echo Code starting with the faulting instruction  > $T.aa
 237 echo =========================================== >> $T.aa
 238 code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
 239 echo -n "       .$type 0x" > $T.s
 240 echo $code >> $T.s
 241 disas $T 0
 242 cat $T.dis >> $T.aa
 243
 244 cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
 245 echo
 246 cat $T.aa
 247 cleanup