[PATCH 1/1] scripts/decodecode: update from Linux v6.10

[Heinrich Schuchardt]

For decoding RISC-V dumps we need to update the script.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
 scripts/decodecode | 169 +++++++++++++++++++++++++++++++++++++++------
 1 file changed, 148 insertions(+), 21 deletions(-)

diff --git a/scripts/decodecode b/scripts/decodecode
index 9cef558528..6364218b21 100755
--- a/scripts/decodecode
+++ b/scripts/decodecode
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # SPDX-License-Identifier: GPL-2.0
 # Disassemble the Code: line in Linux oopses
 # usage: decodecode < oops.file
@@ -6,6 +6,9 @@
 # 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
@@ -60,15 +63,27 @@ case $width in
 4) type=4byte ;;
 esac
 
+if [ -z "$ARCH" ]; then
+    case `uname -m` in
+	aarch64*) ARCH=arm64 ;;
+	arm*) ARCH=arm ;;
+	loongarch*) ARCH=loongarch ;;
+    esac
+fi
+
+# Params: (tmp_file, pc_sub)
 disas() {
-	${CROSS_COMPILE}as $AFLAGS -o $1.o $1.s > /dev/null 2>&1
+	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 $1.o
+		${CROSS_COMPILE}strip $t.o
 	fi
 
 	if [ "$ARCH" = "arm64" ]; then
@@ -76,11 +91,120 @@ disas() {
 			type=inst
 		fi
 
-		${CROSS_COMPILE}strip $1.o
+		${CROSS_COMPILE}strip $t.o
+	fi
+
+	if [ "$ARCH" = "riscv" ]; then
+		OBJDUMPFLAGS="-M no-aliases --section=.text -D"
+		${CROSS_COMPILE}strip $t.o
+	fi
+
+	if [ "$ARCH" = "loongarch" ]; then
+		${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 $1.o | \
-		grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1
+	${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" "\<"`
@@ -90,36 +214,39 @@ 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
+
+	disas $T $pc_sub
+
 	cat $T.dis >> $T.oo
-	rm -f $T.o $T.s $T.dis
 
-# and fix code at-and-after marker
+	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 $code | sed -e 's/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
+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
+disas $T 0
 cat $T.dis >> $T.aa
 
-# (lines of whole $T.oo) - (lines of $T.aa, i.e. "Code starting") + 3,
-# i.e. the title + the "===..=" line (sed is counting from 1, 0 address is
-# special)
-faultlinenum=$(( $(wc -l $T.oo  | cut -d" " -f1) - \
-		 $(wc -l $T.aa  | cut -d" " -f1) + 3))
-
-faultline=`cat $T.dis | head -1 | cut -d":" -f2-`
-faultline=`echo "$faultline" | sed -e 's/\[/\\\[/g; s/\]/\\\]/g'`
-
-cat $T.oo | sed -e "${faultlinenum}s/^\(.*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
+cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
 echo
 cat $T.aa
 cleanup
-- 
2.45.2