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![Björn Töpel](/assets/img/avatar_default.png)
RISC-V has some GNU disassembly quirks, e.g. it requires '-D' to properly disassemble .2byte directives similar to Arm [1]. Further, GNU objdump groups RISC-V instruction by 2 or 4 byte chunks, instead doing byte-for-byte. Add the required switches, and translate from short/word to bytes when ARCH is "riscv". An example how to invoke decodecode for RISC-V: $ echo 'Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7) 6140' | AFLAGS="-march=rv64imac_zicbom_zihintpause" \ ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- ./scripts/decodecode Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7) 6140 All code ======== 0: bf45 c.j 0xffffffffffffffb0 2: 1007f793 andi a5,a5,256 6: f7d9 c.bnez a5,0xffffffffffffff94 8: 37af50ef jal ra,0xf5382 c: d541 c.beqz a0,0xffffffffffffff94 e: b7d9 c.j 0xffffffffffffffd4 10: 00c87097 auipc ra,0xc87 14:* 614080e7 jalr ra,1556(ra) # 0xc87624 <-- trapping instruction Code starting with the faulting instruction =========================================== 0: 614080e7 jalr ra,1556(ra) [1] https://sourceware.org/bugzilla/show_bug.cgi?id=10263 Signed-off-by: Björn Töpel <bjorn@rivosinc.com> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20230119074738.708301-3-bjorn@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
247 lines
4.8 KiB
Bash
Executable file
247 lines
4.8 KiB
Bash
Executable file
#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0
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# Disassemble the Code: line in Linux oopses
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# usage: decodecode < oops.file
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#
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# options: set env. variable AFLAGS=options to pass options to "as";
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# e.g., to decode an i386 oops on an x86_64 system, use:
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# AFLAGS=--32 decodecode < 386.oops
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# PC=hex - the PC (program counter) the oops points to
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faultlinenum=1
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cleanup() {
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rm -f $T $T.s $T.o $T.oo $T.aa $T.dis
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exit 1
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}
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die() {
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echo "$@"
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exit 1
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}
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trap cleanup EXIT
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T=`mktemp` || die "cannot create temp file"
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code=
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cont=
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while read i ; do
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case "$i" in
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*Code:*)
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code=$i
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cont=yes
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;;
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*)
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[ -n "$cont" ] && {
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xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')"
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if [ -n "$xdump" ]; then
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code="$code $xdump"
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else
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cont=
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fi
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}
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;;
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esac
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done
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if [ -z "$code" ]; then
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rm $T
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exit
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fi
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echo $code
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code=`echo $code | sed -e 's/.*Code: //'`
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width=`expr index "$code" ' '`
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width=$((($width-1)/2))
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case $width in
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1) type=byte ;;
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2) type=2byte ;;
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4) type=4byte ;;
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esac
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if [ -z "$ARCH" ]; then
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case `uname -m` in
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aarch64*) ARCH=arm64 ;;
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arm*) ARCH=arm ;;
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esac
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fi
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# Params: (tmp_file, pc_sub)
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disas() {
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t=$1
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pc_sub=$2
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${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1
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if [ "$ARCH" = "arm" ]; then
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if [ $width -eq 2 ]; then
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OBJDUMPFLAGS="-M force-thumb"
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fi
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${CROSS_COMPILE}strip $t.o
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fi
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if [ "$ARCH" = "arm64" ]; then
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if [ $width -eq 4 ]; then
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type=inst
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fi
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${CROSS_COMPILE}strip $t.o
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fi
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if [ "$ARCH" = "riscv" ]; then
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OBJDUMPFLAGS="-M no-aliases --section=.text -D"
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${CROSS_COMPILE}strip $t.o
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fi
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if [ $pc_sub -ne 0 ]; then
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if [ $PC ]; then
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adj_vma=$(( $PC - $pc_sub ))
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OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma"
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fi
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fi
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${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \
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grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1
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}
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# Match the maximum number of opcode bytes from @op_bytes contained within
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# @opline
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#
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# Params:
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# @op_bytes: The string of bytes from the Code: line
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# @opline: The disassembled line coming from objdump
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#
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# Returns:
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# The max number of opcode bytes from the beginning of @op_bytes which match
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# the opcode bytes in the objdump line.
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get_substr_opcode_bytes_num()
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{
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local op_bytes=$1
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local opline=$2
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local retval=0
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substr=""
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for opc in $op_bytes;
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do
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substr+="$opc"
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opcode="$substr"
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if [ "$ARCH" = "riscv" ]; then
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opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
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fi
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# return if opcode bytes do not match @opline anymore
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if ! echo $opline | grep -q "$opcode";
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then
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break
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fi
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# add trailing space
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substr+=" "
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retval=$((retval+1))
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done
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return $retval
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}
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# Return the line number in objdump output to where the IP marker in the Code:
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# line points to
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#
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# Params:
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# @all_code: code in bytes without the marker
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# @dis_file: disassembled file
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# @ip_byte: The byte to which the IP points to
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get_faultlinenum()
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{
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local all_code="$1"
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local dis_file="$2"
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# num bytes including IP byte
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local num_bytes_ip=$(( $3 + 1 * $width ))
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# Add the two header lines (we're counting from 1).
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local retval=3
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# remove marker
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all_code=$(echo $all_code | sed -e 's/[<>()]//g')
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while read line
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do
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get_substr_opcode_bytes_num "$all_code" "$line"
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ate_opcodes=$?
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if ! (( $ate_opcodes )); then
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continue
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fi
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num_bytes_ip=$((num_bytes_ip - ($ate_opcodes * $width) ))
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if (( $num_bytes_ip <= 0 )); then
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break
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fi
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# Delete matched opcode bytes from all_code. For that, compute
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# how many chars those opcodes are represented by and include
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# trailing space.
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#
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# a byte is 2 chars, ate_opcodes is also the number of trailing
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# spaces
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del_chars=$(( ($ate_opcodes * $width * 2) + $ate_opcodes ))
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all_code=$(echo $all_code | sed -e "s!^.\{$del_chars\}!!")
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let "retval+=1"
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done < $dis_file
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return $retval
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}
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marker=`expr index "$code" "\<"`
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if [ $marker -eq 0 ]; then
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marker=`expr index "$code" "\("`
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fi
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touch $T.oo
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if [ $marker -ne 0 ]; then
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# How many bytes to subtract from the program counter
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# in order to get to the beginning virtual address of the
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# Code:
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pc_sub=$(( (($marker - 1) / (2 * $width + 1)) * $width ))
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echo All code >> $T.oo
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echo ======== >> $T.oo
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beforemark=`echo "$code"`
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echo -n " .$type 0x" > $T.s
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echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s
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disas $T $pc_sub
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cat $T.dis >> $T.oo
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get_faultlinenum "$code" "$T.dis" $pc_sub
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faultlinenum=$?
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# and fix code at-and-after marker
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code=`echo "$code" | cut -c$((${marker} + 1))-`
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rm -f $T.o $T.s $T.dis
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fi
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echo Code starting with the faulting instruction > $T.aa
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echo =========================================== >> $T.aa
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code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
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echo -n " .$type 0x" > $T.s
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echo $code >> $T.s
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disas $T 0
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cat $T.dis >> $T.aa
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cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
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echo
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cat $T.aa
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cleanup
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