Home Home > GIT Browse > vanilla
summaryrefslogtreecommitdiff
blob: e476caf524143c19e23efc4335c0a5a6e2ccf5cc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
#!/usr/bin/env perl
# SPDX-License-Identifier: GPL-2.0-only

use File::Basename;
use Math::BigInt;
use Getopt::Long;

# Copyright 2008, Intel Corporation
#
# This file is part of the Linux kernel
#
# Authors:
# 	Arjan van de Ven <arjan@linux.intel.com>


my $cross_compile = "";
my $vmlinux_name = "";
my $modulefile = "";

# Get options
Getopt::Long::GetOptions(
	'cross-compile|c=s'	=> \$cross_compile,
	'module|m=s'		=> \$modulefile,
	'help|h'		=> \&usage,
) || usage ();
my $vmlinux_name = $ARGV[0];
if (!defined($vmlinux_name)) {
	my $kerver = `uname -r`;
	chomp($kerver);
	$vmlinux_name = "/lib/modules/$kerver/build/vmlinux";
	print "No vmlinux specified, assuming $vmlinux_name\n";
}
my $filename = $vmlinux_name;

# Parse the oops to find the EIP value

my $target = "0";
my $function;
my $module = "";
my $func_offset = 0;
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"} = $4;
	}
	if ($line =~ /RAX: ([0-9a-f]+) RBX: ([0-9a-f]+) RCX: ([0-9a-f]+)/) {
		$regs{"%eax"} = $1;
		$regs{"%ebx"} = $2;
		$regs{"%ecx"} = $3;
	}
	if ($line =~ /RDX: ([0-9a-f]+) RSI: ([0-9a-f]+) RDI: ([0-9a-f]+)/) {
		$regs{"%edx"} = $1;
		$regs{"%esi"} = $2;
		$regs{"%edi"} = $3;
	}
	if ($line =~ /RBP: ([0-9a-f]+) R08: ([0-9a-f]+) R09: ([0-9a-f]+)/) {
		$regs{"%r08"} = $2;
		$regs{"%r09"} = $3;
	}
	if ($line =~ /R10: ([0-9a-f]+) R11: ([0-9a-f]+) R12: ([0-9a-f]+)/) {
		$regs{"%r10"} = $1;
		$regs{"%r11"} = $2;
		$regs{"%r12"} = $3;
	}
	if ($line =~ /R13: ([0-9a-f]+) R14: ([0-9a-f]+) R15: ([0-9a-f]+)/) {
		$regs{"%r13"} = $1;
		$regs{"%r14"} = $2;
		$regs{"%r15"} = $3;
	}
}

sub reg_name
{
	my ($reg) = @_;
	$reg =~ s/r(.)x/e\1x/;
	$reg =~ s/r(.)i/e\1i/;
	$reg =~ s/r(.)p/e\1p/;
	return $reg;
}

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 $clobberprime = reg_name($clobber);
		my $lastwordprime = reg_name($lastword);
		my $val = $regs{$reg};
		if ($val =~ /^[0]+$/) {
			$val = "0";
		} else {
			$val =~ s/^0*//;
		}

		# first check if we're clobbering this register; if we do
		# we print it with a =>, and then delete its value
		if ($clobber =~ /$reg/ || $clobberprime =~ /$reg/) {
			if (length($val) > 0) {
				$str = $str . " $reg => $val ";
			}
			$regs{$reg} = "";
			$val = "";
		}
		# now check if we're reading this register
		if ($lastword =~ /$reg/ || $lastwordprime =~ /$reg/) {
			if (length($val) > 0) {
				$str = $str . " $reg = $val ";
			}
		}
	}
	return $str;
}

# parse the oops
while (<STDIN>) {
	my $line = $_;
	if ($line =~ /EIP: 0060:\[\<([a-z0-9]+)\>\]/) {
		$target = $1;
	}
	if ($line =~ /RIP: 0010:\[\<([a-z0-9]+)\>\]/) {
		$target = $1;
	}
	if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {
		$function = $1;
		$func_offset = $2;
	}
	if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\]  \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {
		$function = $1;
		$func_offset = $2;
	}

	# check if it's a module
	if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
		$module = $3;
	}
	if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\]  \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
		$module = $3;
	}
	parse_x86_regs($line);
}

my $decodestart = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$func_offset");
my $decodestop = Math::BigInt->from_hex("0x$target") + 8192;
if ($target eq "0") {
	print "No oops found!\n";
	usage();
}

# if it's a module, we need to find the .ko file and calculate a load offset
if ($module ne "") {
	if ($modulefile eq "") {
		$modulefile = `modinfo -F filename $module`;
		chomp($modulefile);
	}
	$filename = $modulefile;
	if ($filename eq "") {
		print "Module .ko file for $module not found. Aborting\n";
		exit;
	}
	# ok so we found the module, now we need to calculate the vma offset
	open(FILE, $cross_compile."objdump -dS $filename |") || die "Cannot start objdump";
	while (<FILE>) {
		if ($_ =~ /^([0-9a-f]+) \<$function\>\:/) {
			my $fu = $1;
			$vmaoffset = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$fu") - Math::BigInt->from_hex("0x$func_offset");
		}
	}
	close(FILE);
}

my $counter = 0;
my $state   = 0;
my $center  = -1;
my @lines;
my @reglines;

sub InRange {
	my ($address, $target) = @_;
	my $ad = "0x".$address;
	my $ta = "0x".$target;
	my $delta = Math::BigInt->from_hex($ad) - Math::BigInt->from_hex($ta);

	if (($delta > -4096) && ($delta < 4096)) {
		return 1;
	}
	return 0;
}



# first, parse the input into the lines array, but to keep size down,
# we only do this for 4Kb around the sweet spot

open(FILE, $cross_compile."objdump -dS --adjust-vma=$vmaoffset --start-address=$decodestart --stop-address=$decodestop $filename |") || die "Cannot start objdump";

while (<FILE>) {
	my $line = $_;
	chomp($line);
	if ($state == 0) {
		if ($line =~ /^([a-f0-9]+)\:/) {
			if (InRange($1, $target)) {
				$state = 1;
			}
		}
	}
	if ($state == 1) {
		if ($line =~ /^([a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]+)\:/) {
			my $val = $1;
			if (!InRange($val, $target)) {
				last;
			}
			if ($val eq $target) {
				$center = $counter;
			}
		}
		$lines[$counter] = $line;

		$counter = $counter + 1;
	}
}

close(FILE);

if ($counter == 0) {
	print "No matching code found \n";
	exit;
}

if ($center == -1) {
	print "No matching code found \n";
	exit;
}

my $start;
my $finish;
my $codelines = 0;
my $binarylines = 0;
# now we go up and down in the array to find how much we want to print

$start = $center;

while ($start > 1) {
	$start = $start - 1;
	my $line = $lines[$start];
	if ($line =~ /^([a-f0-9]+)\:/) {
		$binarylines = $binarylines + 1;
	} else {
		$codelines = $codelines + 1;
	}
	if ($codelines > 10) {
		last;
	}
	if ($binarylines > 20) {
		last;
	}
}


$finish = $center;
$codelines = 0;
$binarylines = 0;
while ($finish < $counter) {
	$finish = $finish + 1;
	my $line = $lines[$finish];
	if ($line =~ /^([a-f0-9]+)\:/) {
		$binarylines = $binarylines + 1;
	} else {
		$codelines = $codelines + 1;
	}
	if ($codelines > 10) {
		last;
	}
	if ($binarylines > 20) {
		last;
	}
}


my $i;


# 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) {
		$line =  "*$lines[$i] ";
	} else {
		$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;
}

sub usage {
	print <<EOT;
Usage:
  dmesg | perl $0 [OPTION] [VMLINUX]

OPTION:
  -c, --cross-compile CROSS_COMPILE	Specify the prefix used for toolchain.
  -m, --module MODULE_DIRNAME		Specify the module filename.
  -h, --help				Help.
EOT
	exit;
}