From dcecc6c70013e3a5fa81b3081480c03e10670a23 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sun, 15 Jul 2007 23:41:15 -0700 Subject: [PATCH] doc/oops-tracing: add Code: decode info Add info that the Code: bytes line contains or (wxyz) in some architecture oops reports and what that means. Add a script by Andi Kleen that reads the Code: line from an Oops report file and generates assembly code from the hex bytes. Signed-off-by: Randy Dunlap Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/oops-tracing.txt | 14 ++++++++++ scripts/decodecode | 51 ++++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+) create mode 100644 scripts/decodecode diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt index 7d5b60dea551..23e6dde7eea6 100644 --- a/Documentation/oops-tracing.txt +++ b/Documentation/oops-tracing.txt @@ -86,6 +86,20 @@ stuff are the values reported by the Oops - you can just cut-and-paste and do a replace of spaces to "\x" - that's what I do, as I'm too lazy to write a program to automate this all). +Alternatively, you can use the shell script in scripts/decodecode. +Its usage is: decodecode < oops.txt + +The hex bytes that follow "Code:" may (in some architectures) have a series +of bytes that precede the current instruction pointer as well as bytes at and +following the current instruction pointer. In some cases, one instruction +byte or word is surrounded by <> or (), as in "<86>" or "(f00d)". These +<> or () markings indicate the current instruction pointer. Example from +i386, split into multiple lines for readability: + +Code: f9 0f 8d f9 00 00 00 8d 42 0c e8 dd 26 11 c7 a1 60 ea 2b f9 8b 50 08 a1 +64 ea 2b f9 8d 34 82 8b 1e 85 db 74 6d 8b 15 60 ea 2b f9 <8b> 43 04 39 42 54 +7e 04 40 89 42 54 8b 43 04 3b 05 00 f6 52 c0 + Finally, if you want to see where the code comes from, you can do cd /usr/src/linux diff --git a/scripts/decodecode b/scripts/decodecode new file mode 100644 index 000000000000..1e1a8f620c47 --- /dev/null +++ b/scripts/decodecode @@ -0,0 +1,51 @@ +#!/bin/sh +# 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 + +T=`mktemp` +code= + +while read i ; do + +case "$i" in +*Code:*) + code=$i + ;; +esac + +done + +if [ -z "$code" ]; then + exit +fi + +echo $code +code=`echo $code | sed -e 's/.*Code: //'` + +marker=`expr index "$code" "\<"` +if [ $marker -eq 0 ]; then + marker=`expr index "$code" "\("` +fi + +if [ $marker -ne 0 ]; then + beforemark=`echo "$code" | cut -c-$((${marker} - 1))` + echo -n " .byte 0x" > $T.s + echo $beforemark | sed -e 's/ /,0x/g' >> $T.s + as $AFLAGS -o $T.o $T.s + objdump -S $T.o + rm $T.o $T.s + +# and fix code at-and-after marker + code=`echo "$code" | cut -c$((${marker} + 1))-` +fi + +code=`echo $code | sed -e 's/ [<(]/ /;s/[>)] / /;s/ /,0x/g'` +echo -n " .byte 0x" > $T.s +echo $code >> $T.s +as $AFLAGS -o $T.o $T.s +objdump -S $T.o +rm $T.o $T.s