1 #!/usr/bin/env perl
2 # SPDX-License-Identifier: GPL-2.0-only
3
4 use File::Basename;
5 use Math::BigInt;
6 use Getopt::Long;
7
8 # Copyright 2008, Intel Corporation
9 #
10 # This file is part of the Linux kernel
11 #
12 # Authors:
13 # Arjan van de Ven <arjan@linux.intel.com>
14
15
16 my $cross_compile = "";
17 my $vmlinux_name = "";
18 my $modulefile = "";
19
20 # Get options
21 Getopt::Long::GetOptions(
22 'cross-compile|c=s' => \$cross_compile,
23 'module|m=s' => \$modulefile,
24 'help|h' => \&usage,
25 ) || usage ();
26 my $vmlinux_name = $ARGV[0];
27 if (!defined($vmlinux_name)) {
28 my $kerver = `uname -r`;
29 chomp($kerver);
30 $vmlinux_name = "/lib/modules/$kerver/build/vmlinux";
31 print "No vmlinux specified, assuming $vmlinux_name\n";
32 }
33 my $filename = $vmlinux_name;
34
35 # Parse the oops to find the EIP value
36
37 my $target = "0";
38 my $function;
39 my $module = "";
40 my $func_offset = 0;
41 my $vmaoffset = 0;
42
43 my %regs;
44
45
46 sub parse_x86_regs
47 {
48 my ($line) = @_;
49 if ($line =~ /EAX: ([0-9a-f]+) EBX: ([0-9a-f]+) ECX: ([0-9a-f]+) EDX: ([0-9a-f]+)/) {
50 $regs{"%eax"} = $1;
51 $regs{"%ebx"} = $2;
52 $regs{"%ecx"} = $3;
53 $regs{"%edx"} = $4;
54 }
55 if ($line =~ /ESI: ([0-9a-f]+) EDI: ([0-9a-f]+) EBP: ([0-9a-f]+) ESP: ([0-9a-f]+)/) {
56 $regs{"%esi"} = $1;
57 $regs{"%edi"} = $2;
58 $regs{"%esp"} = $4;
59 }
60 if ($line =~ /RAX: ([0-9a-f]+) RBX: ([0-9a-f]+) RCX: ([0-9a-f]+)/) {
61 $regs{"%eax"} = $1;
62 $regs{"%ebx"} = $2;
63 $regs{"%ecx"} = $3;
64 }
65 if ($line =~ /RDX: ([0-9a-f]+) RSI: ([0-9a-f]+) RDI: ([0-9a-f]+)/) {
66 $regs{"%edx"} = $1;
67 $regs{"%esi"} = $2;
68 $regs{"%edi"} = $3;
69 }
70 if ($line =~ /RBP: ([0-9a-f]+) R08: ([0-9a-f]+) R09: ([0-9a-f]+)/) {
71 $regs{"%r08"} = $2;
72 $regs{"%r09"} = $3;
73 }
74 if ($line =~ /R10: ([0-9a-f]+) R11: ([0-9a-f]+) R12: ([0-9a-f]+)/) {
75 $regs{"%r10"} = $1;
76 $regs{"%r11"} = $2;
77 $regs{"%r12"} = $3;
78 }
79 if ($line =~ /R13: ([0-9a-f]+) R14: ([0-9a-f]+) R15: ([0-9a-f]+)/) {
80 $regs{"%r13"} = $1;
81 $regs{"%r14"} = $2;
82 $regs{"%r15"} = $3;
83 }
84 }
85
86 sub reg_name
87 {
88 my ($reg) = @_;
89 $reg =~ s/r(.)x/e\1x/;
90 $reg =~ s/r(.)i/e\1i/;
91 $reg =~ s/r(.)p/e\1p/;
92 return $reg;
93 }
94
95 sub process_x86_regs
96 {
97 my ($line, $cntr) = @_;
98 my $str = "";
99 if (length($line) < 40) {
100 return ""; # not an asm istruction
101 }
102
103 # find the arguments to the instruction
104 if ($line =~ /([0-9a-zA-Z\,\%\(\)\-\+]+)$/) {
105 $lastword = $1;
106 } else {
107 return "";
108 }
109
110 # we need to find the registers that get clobbered,
111 # since their value is no longer relevant for previous
112 # instructions in the stream.
113
114 $clobber = $lastword;
115 # first, remove all memory operands, they're read only
116 $clobber =~ s/\([a-z0-9\%\,]+\)//g;
117 # then, remove everything before the comma, thats the read part
118 $clobber =~ s/.*\,//g;
119
120 # if this is the instruction that faulted, we haven't actually done
121 # the write yet... nothing is clobbered.
122 if ($cntr == 0) {
123 $clobber = "";
124 }
125
126 foreach $reg (keys(%regs)) {
127 my $clobberprime = reg_name($clobber);
128 my $lastwordprime = reg_name($lastword);
129 my $val = $regs{$reg};
130 if ($val =~ /^[0]+$/) {
131 $val = "0";
132 } else {
133 $val =~ s/^0*//;
134 }
135
136 # first check if we're clobbering this register; if we do
137 # we print it with a =>, and then delete its value
138 if ($clobber =~ /$reg/ || $clobberprime =~ /$reg/) {
139 if (length($val) > 0) {
140 $str = $str . " $reg => $val ";
141 }
142 $regs{$reg} = "";
143 $val = "";
144 }
145 # now check if we're reading this register
146 if ($lastword =~ /$reg/ || $lastwordprime =~ /$reg/) {
147 if (length($val) > 0) {
148 $str = $str . " $reg = $val ";
149 }
150 }
151 }
152 return $str;
153 }
154
155 # parse the oops
156 while (<STDIN>) {
157 my $line = $_;
158 if ($line =~ /EIP: 0060:\[\<([a-z0-9]+)\>\]/) {
159 $target = $1;
160 }
161 if ($line =~ /RIP: 0010:\[\<([a-z0-9]+)\>\]/) {
162 $target = $1;
163 }
164 if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {
165 $function = $1;
166 $func_offset = $2;
167 }
168 if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\] \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+0x([0-9a-f]+)\/0x[a-f0-9]/) {
169 $function = $1;
170 $func_offset = $2;
171 }
172
173 # check if it's a module
174 if ($line =~ /EIP is at ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
175 $module = $3;
176 }
177 if ($line =~ /RIP: 0010:\[\<[0-9a-f]+\>\] \[\<[0-9a-f]+\>\] ([a-zA-Z0-9\_]+)\+(0x[0-9a-f]+)\/0x[a-f0-9]+\W\[([a-zA-Z0-9\_\-]+)\]/) {
178 $module = $3;
179 }
180 parse_x86_regs($line);
181 }
182
183 my $decodestart = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$func_offset");
184 my $decodestop = Math::BigInt->from_hex("0x$target") + 8192;
185 if ($target eq "0") {
186 print "No oops found!\n";
187 usage();
188 }
189
190 # if it's a module, we need to find the .ko file and calculate a load offset
191 if ($module ne "") {
192 if ($modulefile eq "") {
193 $modulefile = `modinfo -F filename $module`;
194 chomp($modulefile);
195 }
196 $filename = $modulefile;
197 if ($filename eq "") {
198 print "Module .ko file for $module not found. Aborting\n";
199 exit;
200 }
201 # ok so we found the module, now we need to calculate the vma offset
202 open(FILE, $cross_compile."objdump -dS $filename |") || die "Cannot start objdump";
203 while (<FILE>) {
204 if ($_ =~ /^([0-9a-f]+) \<$function\>\:/) {
205 my $fu = $1;
206 $vmaoffset = Math::BigInt->from_hex("0x$target") - Math::BigInt->from_hex("0x$fu") - Math::BigInt->from_hex("0x$func_offset");
207 }
208 }
209 close(FILE);
210 }
211
212 my $counter = 0;
213 my $state = 0;
214 my $center = -1;
215 my @lines;
216 my @reglines;
217
218 sub InRange {
219 my ($address, $target) = @_;
220 my $ad = "0x".$address;
221 my $ta = "0x".$target;
222 my $delta = Math::BigInt->from_hex($ad) - Math::BigInt->from_hex($ta);
223
224 if (($delta > -4096) && ($delta < 4096)) {
225 return 1;
226 }
227 return 0;
228 }
229
230
231
232 # first, parse the input into the lines array, but to keep size down,
233 # we only do this for 4Kb around the sweet spot
234
235 open(FILE, $cross_compile."objdump -dS --adjust-vma=$vmaoffset --start-address=$decodestart --stop-address=$decodestop $filename |") || die "Cannot start objdump";
236
237 while (<FILE>) {
238 my $line = $_;
239 chomp($line);
240 if ($state == 0) {
241 if ($line =~ /^([a-f0-9]+)\:/) {
242 if (InRange($1, $target)) {
243 $state = 1;
244 }
245 }
246 }
247 if ($state == 1) {
248 if ($line =~ /^([a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]+)\:/) {
249 my $val = $1;
250 if (!InRange($val, $target)) {
251 last;
252 }
253 if ($val eq $target) {
254 $center = $counter;
255 }
256 }
257 $lines[$counter] = $line;
258
259 $counter = $counter + 1;
260 }
261 }
262
263 close(FILE);
264
265 if ($counter == 0) {
266 print "No matching code found \n";
267 exit;
268 }
269
270 if ($center == -1) {
271 print "No matching code found \n";
272 exit;
273 }
274
275 my $start;
276 my $finish;
277 my $codelines = 0;
278 my $binarylines = 0;
279 # now we go up and down in the array to find how much we want to print
280
281 $start = $center;
282
283 while ($start > 1) {
284 $start = $start - 1;
285 my $line = $lines[$start];
286 if ($line =~ /^([a-f0-9]+)\:/) {
287 $binarylines = $binarylines + 1;
288 } else {
289 $codelines = $codelines + 1;
290 }
291 if ($codelines > 10) {
292 last;
293 }
294 if ($binarylines > 20) {
295 last;
296 }
297 }
298
299
300 $finish = $center;
301 $codelines = 0;
302 $binarylines = 0;
303 while ($finish < $counter) {
304 $finish = $finish + 1;
305 my $line = $lines[$finish];
306 if ($line =~ /^([a-f0-9]+)\:/) {
307 $binarylines = $binarylines + 1;
308 } else {
309 $codelines = $codelines + 1;
310 }
311 if ($codelines > 10) {
312 last;
313 }
314 if ($binarylines > 20) {
315 last;
316 }
317 }
318
319
320 my $i;
321
322
323 # start annotating the registers in the asm.
324 # this goes from the oopsing point back, so that the annotator
325 # can track (opportunistically) which registers got written and
326 # whos value no longer is relevant.
327
328 $i = $center;
329 while ($i >= $start) {
330 $reglines[$i] = process_x86_regs($lines[$i], $center - $i);
331 $i = $i - 1;
332 }
333
334 $i = $start;
335 while ($i < $finish) {
336 my $line;
337 if ($i == $center) {
338 $line = "*$lines[$i] ";
339 } else {
340 $line = " $lines[$i] ";
341 }
342 print $line;
343 if (defined($reglines[$i]) && length($reglines[$i]) > 0) {
344 my $c = 60 - length($line);
345 while ($c > 0) { print " "; $c = $c - 1; };
346 print "| $reglines[$i]";
347 }
348 if ($i == $center) {
349 print "<--- faulting instruction";
350 }
351 print "\n";
352 $i = $i +1;
353 }
354
355 sub usage {
356 print <<EOT;
357 Usage:
358 dmesg | perl $0 [OPTION] [VMLINUX]
359
360 OPTION:
361 -c, --cross-compile CROSS_COMPILE Specify the prefix used for toolchain.
362 -m, --module MODULE_DIRNAME Specify the module filename.
363 -h, --help Help.
364 EOT
365 exit;
366 }
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