1#!/usr/bin/env perl
2
3use File::Basename;
4use Math::BigInt;
5use Getopt::Long;
6
7# Copyright 2008, Intel Corporation
8#
9# This file is part of the Linux kernel
10#
11# This program file is free software; you can redistribute it and/or modify it
12# under the terms of the GNU General Public License as published by the
13# Free Software Foundation; version 2 of the License.
14#
15# Authors:
16# 	Arjan van de Ven <arjan@linux.intel.com>
17
18
19my $cross_compile = "";
20my $vmlinux_name = "";
21my $modulefile = "";
22
23# Get options
24Getopt::Long::GetOptions(
25	'cross-compile|c=s'	=> \$cross_compile,
26	'module|m=s'		=> \$modulefile,
27	'help|h'		=> \&usage,
28) || usage ();
29my $vmlinux_name = $ARGV[0];
30if (!defined($vmlinux_name)) {
31	my $kerver = `uname -r`;
32	chomp($kerver);
33	$vmlinux_name = "/lib/modules/$kerver/build/vmlinux";
34	print "No vmlinux specified, assuming $vmlinux_name\n";
35}
36my $filename = $vmlinux_name;
37
38# Parse the oops to find the EIP value
39
40my $target = "0";
41my $function;
42my $module = "";
43my $func_offset = 0;
44my $vmaoffset = 0;
45
46my %regs;
47
48
49sub parse_x86_regs
50{
51	my ($line) = @_;
52	if ($line =~ /EAX: ([0-9a-f]+) EBX: ([0-9a-f]+) ECX: ([0-9a-f]+) EDX: ([0-9a-f]+)/) {
53		$regs{"%eax"} = $1;
54		$regs{"%ebx"} = $2;
55		$regs{"%ecx"} = $3;
56		$regs{"%edx"} = $4;
57	}
58	if ($line =~ /ESI: ([0-9a-f]+) EDI: ([0-9a-f]+) EBP: ([0-9a-f]+) ESP: ([0-9a-f]+)/) {
59		$regs{"%esi"} = $1;
60		$regs{"%edi"} = $2;
61		$regs{"%esp"} = $4;
62	}
63	if ($line =~ /RAX: ([0-9a-f]+) RBX: ([0-9a-f]+) RCX: ([0-9a-f]+)/) {
64		$regs{"%eax"} = $1;
65		$regs{"%ebx"} = $2;
66		$regs{"%ecx"} = $3;
67	}
68	if ($line =~ /RDX: ([0-9a-f]+) RSI: ([0-9a-f]+) RDI: ([0-9a-f]+)/) {
69		$regs{"%edx"} = $1;
70		$regs{"%esi"} = $2;
71		$regs{"%edi"} = $3;
72	}
73	if ($line =~ /RBP: ([0-9a-f]+) R08: ([0-9a-f]+) R09: ([0-9a-f]+)/) {
74		$regs{"%r08"} = $2;
75		$regs{"%r09"} = $3;
76	}
77	if ($line =~ /R10: ([0-9a-f]+) R11: ([0-9a-f]+) R12: ([0-9a-f]+)/) {
78		$regs{"%r10"} = $1;
79		$regs{"%r11"} = $2;
80		$regs{"%r12"} = $3;
81	}
82	if ($line =~ /R13: ([0-9a-f]+) R14: ([0-9a-f]+) R15: ([0-9a-f]+)/) {
83		$regs{"%r13"} = $1;
84		$regs{"%r14"} = $2;
85		$regs{"%r15"} = $3;
86	}
87}
88
89sub reg_name
90{
91	my ($reg) = @_;
92	$reg =~ s/r(.)x/e\1x/;
93	$reg =~ s/r(.)i/e\1i/;
94	$reg =~ s/r(.)p/e\1p/;
95	return $reg;
96}
97
98sub process_x86_regs
99{
100	my ($line, $cntr) = @_;
101	my $str = "";
102	if (length($line) < 40) {
103		return ""; # not an asm istruction
104	}
105
106	# find the arguments to the instruction
107	if ($line =~ /([0-9a-zA-Z\,\%\(\)\-\+]+)$/) {
108		$lastword = $1;
109	} else {
110		return "";
111	}
112
113	# we need to find the registers that get clobbered,
114	# since their value is no longer relevant for previous
115	# instructions in the stream.
116
117	$clobber = $lastword;
118	# first, remove all memory operands, they're read only
119	$clobber =~ s/\([a-z0-9\%\,]+\)//g;
120	# then, remove everything before the comma, thats the read part
121	$clobber =~ s/.*\,//g;
122
123	# if this is the instruction that faulted, we haven't actually done
124	# the write yet... nothing is clobbered.
125	if ($cntr == 0) {
126		$clobber = "";
127	}
128
129	foreach $reg (keys(%regs)) {
130		my $clobberprime = reg_name($clobber);
131		my $lastwordprime = reg_name($lastword);
132		my $val = $regs{$reg};
133		if ($val =~ /^[0]+$/) {
134			$val = "0";
135		} else {
136			$val =~ s/^0*//;
137		}
138
139		# first check if we're clobbering this register; if we do
140		# we print it with a =>, and then delete its value
141		if ($clobber =~ /$reg/ || $clobberprime =~ /$reg/) {
142			if (length($val) > 0) {
143				$str = $str . " $reg => $val ";
144			}
145			$regs{$reg} = "";
146			$val = "";
147		}
148		# now check if we're reading this register
149		if ($lastword =~ /$reg/ || $lastwordprime =~ /$reg/) {
150			if (length($val) > 0) {
151				$str = $str . " $reg = $val ";
152			}
153		}
154	}
155	return $str;
156}
157
158# parse the oops
159while (<STDIN>) {
160	my $line = $_;
161	if ($line =~ /EIP: 0060:\[\<([a-z0-9]+)\>\]/) {
162		$target = $1;
163	}
164	if ($line =~ /RIP: 0010:\[\<([a-z0-9]+)\>\]/) {
165		$target = $1;
166	}
167	if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {
168		$function = $1;
169		$func_offset = $2;
170	}
171	if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\]  \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {
172		$function = $1;
173		$func_offset = $2;
174	}
175
176	# check if it's a module
177	if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
178		$module = $3;
179	}
180	if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\]  \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
181		$module = $3;
182	}
183	parse_x86_regs($line);
184}
185
186my $decodestart = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$func_offset");
187my $decodestop = Math::BigInt->from_hex("0x$target") + 8192;
188if ($target eq "0") {
189	print "No oops found!\n";
190	usage();
191}
192
193# if it's a module, we need to find the .ko file and calculate a load offset
194if ($module ne "") {
195	if ($modulefile eq "") {
196		$modulefile = `modinfo -F filename $module`;
197		chomp($modulefile);
198	}
199	$filename = $modulefile;
200	if ($filename eq "") {
201		print "Module .ko file for $module not found. Aborting\n";
202		exit;
203	}
204	# ok so we found the module, now we need to calculate the vma offset
205	open(FILE, $cross_compile."objdump -dS $filename |") || die "Cannot start objdump";
206	while (<FILE>) {
207		if ($_ =~ /^([0-9a-f]+) \<$function\>\:/) {
208			my $fu = $1;
209			$vmaoffset = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$fu") - Math::BigInt->from_hex("0x$func_offset");
210		}
211	}
212	close(FILE);
213}
214
215my $counter = 0;
216my $state   = 0;
217my $center  = -1;
218my @lines;
219my @reglines;
220
221sub InRange {
222	my ($address, $target) = @_;
223	my $ad = "0x".$address;
224	my $ta = "0x".$target;
225	my $delta = Math::BigInt->from_hex($ad) - Math::BigInt->from_hex($ta);
226
227	if (($delta > -4096) && ($delta < 4096)) {
228		return 1;
229	}
230	return 0;
231}
232
233
234
235# first, parse the input into the lines array, but to keep size down,
236# we only do this for 4Kb around the sweet spot
237
238open(FILE, $cross_compile."objdump -dS --adjust-vma=$vmaoffset --start-address=$decodestart --stop-address=$decodestop $filename |") || die "Cannot start objdump";
239
240while (<FILE>) {
241	my $line = $_;
242	chomp($line);
243	if ($state == 0) {
244		if ($line =~ /^([a-f0-9]+)\:/) {
245			if (InRange($1, $target)) {
246				$state = 1;
247			}
248		}
249	}
250	if ($state == 1) {
251		if ($line =~ /^([a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]+)\:/) {
252			my $val = $1;
253			if (!InRange($val, $target)) {
254				last;
255			}
256			if ($val eq $target) {
257				$center = $counter;
258			}
259		}
260		$lines[$counter] = $line;
261
262		$counter = $counter + 1;
263	}
264}
265
266close(FILE);
267
268if ($counter == 0) {
269	print "No matching code found \n";
270	exit;
271}
272
273if ($center == -1) {
274	print "No matching code found \n";
275	exit;
276}
277
278my $start;
279my $finish;
280my $codelines = 0;
281my $binarylines = 0;
282# now we go up and down in the array to find how much we want to print
283
284$start = $center;
285
286while ($start > 1) {
287	$start = $start - 1;
288	my $line = $lines[$start];
289	if ($line =~ /^([a-f0-9]+)\:/) {
290		$binarylines = $binarylines + 1;
291	} else {
292		$codelines = $codelines + 1;
293	}
294	if ($codelines > 10) {
295		last;
296	}
297	if ($binarylines > 20) {
298		last;
299	}
300}
301
302
303$finish = $center;
304$codelines = 0;
305$binarylines = 0;
306while ($finish < $counter) {
307	$finish = $finish + 1;
308	my $line = $lines[$finish];
309	if ($line =~ /^([a-f0-9]+)\:/) {
310		$binarylines = $binarylines + 1;
311	} else {
312		$codelines = $codelines + 1;
313	}
314	if ($codelines > 10) {
315		last;
316	}
317	if ($binarylines > 20) {
318		last;
319	}
320}
321
322
323my $i;
324
325
326# start annotating the registers in the asm.
327# this goes from the oopsing point back, so that the annotator
328# can track (opportunistically) which registers got written and
329# whos value no longer is relevant.
330
331$i = $center;
332while ($i >= $start) {
333	$reglines[$i] = process_x86_regs($lines[$i], $center - $i);
334	$i = $i - 1;
335}
336
337$i = $start;
338while ($i < $finish) {
339	my $line;
340	if ($i == $center) {
341		$line =  "*$lines[$i] ";
342	} else {
343		$line =  " $lines[$i] ";
344	}
345	print $line;
346	if (defined($reglines[$i]) && length($reglines[$i]) > 0) {
347		my $c = 60 - length($line);
348		while ($c > 0) { print " "; $c = $c - 1; };
349		print "| $reglines[$i]";
350	}
351	if ($i == $center) {
352		print "<--- faulting instruction";
353	}
354	print "\n";
355	$i = $i +1;
356}
357
358sub usage {
359	print <<EOT;
360Usage:
361  dmesg | perl $0 [OPTION] [VMLINUX]
362
363OPTION:
364  -c, --cross-compile CROSS_COMPILE	Specify the prefix used for toolchain.
365  -m, --module MODULE_DIRNAME		Specify the module filename.
366  -h, --help				Help.
367EOT
368	exit;
369}
370