scripts: add x86 register parser to markup_oops.pl

An oops dump also contains the register values.

This patch parses these for (32 bit) x86, and then annotates the
disassembly with these values; this helps in analysis of the oops by the
developer, for example, NULL pointer or other pointer bugs show up clearly
this way.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 100 insertions, 6 deletions

diff --git a/scripts/markup_oops.pl b/scripts/markup_oops.pl
index d40449cafa8..bb2046891c9 100644
--- a/scripts/markup_oops.pl
+++ b/scripts/markup_oops.pl
@@ -32,6 +32,78 @@ my $module = "";
 my $func_offset;
 my $vmaoffset = 0;
 
+my %regs;
+
+
+sub parse_x86_regs
+{
+        my ($line) = @_;
+        if ($line =~ /EAX: ([0-9a-f]+) EBX: ([0-9a-f]+) ECX: ([0-9a-f]+) EDX: ([0-9a-f]+)/) {
+                $regs{"%eax"} = $1;
+                $regs{"%ebx"} = $2;
+                $regs{"%ecx"} = $3;
+                $regs{"%edx"} = $4;
+        }
+        if ($line =~ /ESI: ([0-9a-f]+) EDI: ([0-9a-f]+) EBP: ([0-9a-f]+) ESP: ([0-9a-f]+)/) {
+                $regs{"%esi"} = $1;
+                $regs{"%edi"} = $2;
+                $regs{"%esp"} = $4;
+        }
+}
+
+sub process_x86_regs
+{
+        my ($line, $cntr) = @_;
+        my $str = "";
+        if (length($line) < 40) {
+                return ""; # not an asm istruction
+        }
+
+        # find the arguments to the instruction
+        if ($line =~ /([0-9a-zA-Z\,\%\(\)\-\+]+)$/) {
+                $lastword = $1;
+        } else {
+                return "";
+        }
+
+        # we need to find the registers that get clobbered,
+        # since their value is no longer relevant for previous
+        # instructions in the stream.
+
+        $clobber = $lastword;
+        # first, remove all memory operands, they're read only
+        $clobber =~ s/\([a-z0-9\%\,]+\)//g;
+        # then, remove everything before the comma, thats the read part
+        $clobber =~ s/.*\,//g;
+
+        # if this is the instruction that faulted, we haven't actually done
+        # the write yet... nothing is clobbered.
+        if ($cntr == 0) {
+                $clobber = "";
+        }
+
+        foreach $reg (keys(%regs)) {
+                my $val = $regs{$reg};
+                # first check if we're clobbering this register; if we do
+                # we print it with a =>, and then delete its value
+                if ($clobber =~ /$reg/) {
+                        if (length($val) > 0) {
+                                $str = $str . " $reg => $val ";
+                        }
+                        $regs{$reg} = "";
+                        $val = "";
+                }
+                # now check if we're reading this register
+                if ($lastword =~ /$reg/) {
+                        if (length($val) > 0) {
+                                $str = $str . " $reg = $val ";
+                        }
+                }
+        }
+        return $str;
+}
+
+# parse the oops
 while (<STDIN>) {
         my $line = $_;
         if ($line =~ /EIP: 0060:\[\<([a-z0-9]+)\>\]/) {
@@ -46,10 +118,11 @@ while (<STDIN>) {
         if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
                 $module = $3;
         }
+        parse_x86_regs($line);
 }
 
 my $decodestart = hex($target) - hex($func_offset);
-my $decodestop = $decodestart + 8192;
+my $decodestop = hex($target) + 8192;
 if ($target eq "0") {
         print "No oops found!\n";
         print "Usage: \n";
@@ -84,6 +157,7 @@ my $counter = 0;
 my $state   = 0;
 my $center  = 0;
 my @lines;
+my @reglines;
 
 sub InRange {
         my ($address, $target) = @_;
@@ -188,16 +262,36 @@ while ($finish < $counter) {
 
 my $i;
 
-my $fulltext = "";
+
+# start annotating the registers in the asm.
+# this goes from the oopsing point back, so that the annotator
+# can track (opportunistically) which registers got written and
+# whos value no longer is relevant.
+
+$i = $center;
+while ($i >= $start) {
+        $reglines[$i] = process_x86_regs($lines[$i], $center - $i);
+        $i = $i - 1;
+}
+
 $i = $start;
 while ($i < $finish) {
+        my $line;
         if ($i == $center) {
-                $fulltext = $fulltext . "*$lines[$i]     <----- faulting instruction\n";
+                $line =  "*$lines[$i] ";
         } else {
-                $fulltext = $fulltext .  " $lines[$i]\n";
+                $line =  " $lines[$i] ";
+        }
+        print $line;
+        if (defined($reglines[$i]) && length($reglines[$i]) > 0) {
+                my $c = 60 - length($line);
+                while ($c > 0) { print " "; $c = $c - 1; };
+                print "| $reglines[$i]";
         }
+        if ($i == $center) {
+                print "<--- faulting instruction";
+        }
+        print "\n";
         $i = $i +1;
 }
 
-print $fulltext;
-