mm: use the same log level for show_mem()
[linux-2.6.git] / scripts / recordmcount.pl
blobf3c9c0a90b98cad68389da5d591a9921e1cb8f39
1 #!/usr/bin/perl -w
2 # (c) 2008, Steven Rostedt <srostedt@redhat.com>
3 # Licensed under the terms of the GNU GPL License version 2
5 # recordmcount.pl - makes a section called __mcount_loc that holds
6 # all the offsets to the calls to mcount.
9 # What we want to end up with this is that each object file will have a
10 # section called __mcount_loc that will hold the list of pointers to mcount
11 # callers. After final linking, the vmlinux will have within .init.data the
12 # list of all callers to mcount between __start_mcount_loc and __stop_mcount_loc.
13 # Later on boot up, the kernel will read this list, save the locations and turn
14 # them into nops. When tracing or profiling is later enabled, these locations
15 # will then be converted back to pointers to some function.
17 # This is no easy feat. This script is called just after the original
18 # object is compiled and before it is linked.
20 # When parse this object file using 'objdump', the references to the call
21 # sites are offsets from the section that the call site is in. Hence, all
22 # functions in a section that has a call site to mcount, will have the
23 # offset from the beginning of the section and not the beginning of the
24 # function.
26 # But where this section will reside finally in vmlinx is undetermined at
27 # this point. So we can't use this kind of offsets to record the final
28 # address of this call site.
30 # The trick is to change the call offset referring the start of a section to
31 # referring a function symbol in this section. During the link step, 'ld' will
32 # compute the final address according to the information we record.
34 # e.g.
36 # .section ".sched.text", "ax"
37 # [...]
38 # func1:
39 # [...]
40 # call mcount (offset: 0x10)
41 # [...]
42 # ret
43 # .globl fun2
44 # func2: (offset: 0x20)
45 # [...]
46 # [...]
47 # ret
48 # func3:
49 # [...]
50 # call mcount (offset: 0x30)
51 # [...]
53 # Both relocation offsets for the mcounts in the above example will be
54 # offset from .sched.text. If we choose global symbol func2 as a reference and
55 # make another file called tmp.s with the new offsets:
57 # .section __mcount_loc
58 # .quad func2 - 0x10
59 # .quad func2 + 0x10
61 # We can then compile this tmp.s into tmp.o, and link it back to the original
62 # object.
64 # In our algorithm, we will choose the first global function we meet in this
65 # section as the reference. But this gets hard if there is no global functions
66 # in this section. In such a case we have to select a local one. E.g. func1:
68 # .section ".sched.text", "ax"
69 # func1:
70 # [...]
71 # call mcount (offset: 0x10)
72 # [...]
73 # ret
74 # func2:
75 # [...]
76 # call mcount (offset: 0x20)
77 # [...]
78 # .section "other.section"
80 # If we make the tmp.s the same as above, when we link together with
81 # the original object, we will end up with two symbols for func1:
82 # one local, one global. After final compile, we will end up with
83 # an undefined reference to func1 or a wrong reference to another global
84 # func1 in other files.
86 # Since local objects can reference local variables, we need to find
87 # a way to make tmp.o reference the local objects of the original object
88 # file after it is linked together. To do this, we convert func1
89 # into a global symbol before linking tmp.o. Then after we link tmp.o
90 # we will only have a single symbol for func1 that is global.
91 # We can convert func1 back into a local symbol and we are done.
93 # Here are the steps we take:
95 # 1) Record all the local and weak symbols by using 'nm'
96 # 2) Use objdump to find all the call site offsets and sections for
97 # mcount.
98 # 3) Compile the list into its own object.
99 # 4) Do we have to deal with local functions? If not, go to step 8.
100 # 5) Make an object that converts these local functions to global symbols
101 # with objcopy.
102 # 6) Link together this new object with the list object.
103 # 7) Convert the local functions back to local symbols and rename
104 # the result as the original object.
105 # 8) Link the object with the list object.
106 # 9) Move the result back to the original object.
109 use strict;
111 my $P = $0;
112 $P =~ s@.*/@@g;
114 my $V = '0.1';
116 if ($#ARGV != 11) {
117 print "usage: $P arch endian bits objdump objcopy cc ld nm rm mv is_module inputfile\n";
118 print "version: $V\n";
119 exit(1);
122 my ($arch, $endian, $bits, $objdump, $objcopy, $cc,
123 $ld, $nm, $rm, $mv, $is_module, $inputfile) = @ARGV;
125 # This file refers to mcount and shouldn't be ftraced, so lets' ignore it
126 if ($inputfile =~ m,kernel/trace/ftrace\.o$,) {
127 exit(0);
130 # Acceptable sections to record.
131 my %text_sections = (
132 ".text" => 1,
133 ".sched.text" => 1,
134 ".spinlock.text" => 1,
135 ".irqentry.text" => 1,
136 ".text.unlikely" => 1,
139 # Note: we are nice to C-programmers here, thus we skip the '||='-idiom.
140 $objdump = 'objdump' if (!$objdump);
141 $objcopy = 'objcopy' if (!$objcopy);
142 $cc = 'gcc' if (!$cc);
143 $ld = 'ld' if (!$ld);
144 $nm = 'nm' if (!$nm);
145 $rm = 'rm' if (!$rm);
146 $mv = 'mv' if (!$mv);
148 #print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
149 # "'$nm' '$rm' '$mv' '$inputfile'\n";
151 my %locals; # List of local (static) functions
152 my %weak; # List of weak functions
153 my %convert; # List of local functions used that needs conversion
155 my $type;
156 my $local_regex; # Match a local function (return function)
157 my $weak_regex; # Match a weak function (return function)
158 my $section_regex; # Find the start of a section
159 my $function_regex; # Find the name of a function
160 # (return offset and func name)
161 my $mcount_regex; # Find the call site to mcount (return offset)
162 my $alignment; # The .align value to use for $mcount_section
163 my $section_type; # Section header plus possible alignment command
164 my $can_use_local = 0; # If we can use local function references
166 # Shut up recordmcount if user has older objcopy
167 my $quiet_recordmcount = ".tmp_quiet_recordmcount";
168 my $print_warning = 1;
169 $print_warning = 0 if ( -f $quiet_recordmcount);
172 # check_objcopy - whether objcopy supports --globalize-symbols
174 # --globalize-symbols came out in 2.17, we must test the version
175 # of objcopy, and if it is less than 2.17, then we can not
176 # record local functions.
177 sub check_objcopy
179 open (IN, "$objcopy --version |") or die "error running $objcopy";
180 while (<IN>) {
181 if (/objcopy.*\s(\d+)\.(\d+)/) {
182 $can_use_local = 1 if ($1 > 2 || ($1 == 2 && $2 >= 17));
183 last;
186 close (IN);
188 if (!$can_use_local && $print_warning) {
189 print STDERR "WARNING: could not find objcopy version or version " .
190 "is less than 2.17.\n" .
191 "\tLocal function references are disabled.\n";
192 open (QUIET, ">$quiet_recordmcount");
193 printf QUIET "Disables the warning from recordmcount.pl\n";
194 close QUIET;
198 if ($arch =~ /(x86(_64)?)|(i386)/) {
199 if ($bits == 64) {
200 $arch = "x86_64";
201 } else {
202 $arch = "i386";
207 # We base the defaults off of i386, the other archs may
208 # feel free to change them in the below if statements.
210 $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
211 $weak_regex = "^[0-9a-fA-F]+\\s+([wW])\\s+(\\S+)";
212 $section_regex = "Disassembly of section\\s+(\\S+):";
213 $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
214 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
215 $section_type = '@progbits';
216 $type = ".long";
218 if ($arch eq "x86_64") {
219 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
220 $type = ".quad";
221 $alignment = 8;
223 # force flags for this arch
224 $ld .= " -m elf_x86_64";
225 $objdump .= " -M x86-64";
226 $objcopy .= " -O elf64-x86-64";
227 $cc .= " -m64";
229 } elsif ($arch eq "i386") {
230 $alignment = 4;
232 # force flags for this arch
233 $ld .= " -m elf_i386";
234 $objdump .= " -M i386";
235 $objcopy .= " -O elf32-i386";
236 $cc .= " -m32";
238 } elsif ($arch eq "s390" && $bits == 32) {
239 $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_32\\s+_mcount\$";
240 $alignment = 4;
241 $ld .= " -m elf_s390";
242 $cc .= " -m31";
244 } elsif ($arch eq "s390" && $bits == 64) {
245 $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$";
246 $alignment = 8;
247 $type = ".quad";
248 $ld .= " -m elf64_s390";
249 $cc .= " -m64";
251 } elsif ($arch eq "sh") {
252 $alignment = 2;
254 # force flags for this arch
255 $ld .= " -m shlelf_linux";
256 $objcopy .= " -O elf32-sh-linux";
257 $cc .= " -m32";
259 } elsif ($arch eq "powerpc") {
260 $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
261 $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?.*?)>:";
262 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";
264 if ($bits == 64) {
265 $type = ".quad";
268 } elsif ($arch eq "arm") {
269 $alignment = 2;
270 $section_type = '%progbits';
272 } elsif ($arch eq "ia64") {
273 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
274 $type = "data8";
276 if ($is_module eq "0") {
277 $cc .= " -mconstant-gp";
279 } elsif ($arch eq "sparc64") {
280 # In the objdump output there are giblets like:
281 # 0000000000000000 <igmp_net_exit-0x18>:
282 # As there's some data blobs that get emitted into the
283 # text section before the first instructions and the first
284 # real symbols. We don't want to match that, so to combat
285 # this we use '\w' so we'll match just plain symbol names,
286 # and not those that also include hex offsets inside of the
287 # '<>' brackets. Actually the generic function_regex setting
288 # could safely use this too.
289 $function_regex = "^([0-9a-fA-F]+)\\s+<(\\w*?)>:";
291 # Sparc64 calls '_mcount' instead of plain 'mcount'.
292 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
294 $alignment = 8;
295 $type = ".xword";
296 $ld .= " -m elf64_sparc";
297 $cc .= " -m64";
298 $objcopy .= " -O elf64-sparc";
299 } elsif ($arch eq "mips") {
300 # To enable module support, we need to enable the -mlong-calls option
301 # of gcc for module, after using this option, we can not get the real
302 # offset of the calling to _mcount, but the offset of the lui
303 # instruction or the addiu one. herein, we record the address of the
304 # first one, and then we can replace this instruction by a branch
305 # instruction to jump over the profiling function to filter the
306 # indicated functions, or swith back to the lui instruction to trace
307 # them, which means dynamic tracing.
309 # c: 3c030000 lui v1,0x0
310 # c: R_MIPS_HI16 _mcount
311 # c: R_MIPS_NONE *ABS*
312 # c: R_MIPS_NONE *ABS*
313 # 10: 64630000 daddiu v1,v1,0
314 # 10: R_MIPS_LO16 _mcount
315 # 10: R_MIPS_NONE *ABS*
316 # 10: R_MIPS_NONE *ABS*
317 # 14: 03e0082d move at,ra
318 # 18: 0060f809 jalr v1
320 # for the kernel:
322 # 10: 03e0082d move at,ra
323 # 14: 0c000000 jal 0 <loongson_halt>
324 # 14: R_MIPS_26 _mcount
325 # 14: R_MIPS_NONE *ABS*
326 # 14: R_MIPS_NONE *ABS*
327 # 18: 00020021 nop
328 if ($is_module eq "0") {
329 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
330 } else {
331 $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_HI16\\s+_mcount\$";
333 $objdump .= " -Melf-trad".$endian."mips ";
335 if ($endian eq "big") {
336 $endian = " -EB ";
337 $ld .= " -melf".$bits."btsmip";
338 } else {
339 $endian = " -EL ";
340 $ld .= " -melf".$bits."ltsmip";
343 $cc .= " -mno-abicalls -fno-pic -mabi=" . $bits . $endian;
344 $ld .= $endian;
346 if ($bits == 64) {
347 $function_regex =
348 "^([0-9a-fA-F]+)\\s+<(.|[^\$]L.*?|\$[^L].*?|[^\$][^L].*?)>:";
349 $type = ".dword";
351 } elsif ($arch eq "microblaze") {
352 # Microblaze calls '_mcount' instead of plain 'mcount'.
353 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
354 } else {
355 die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
358 my $text_found = 0;
359 my $read_function = 0;
360 my $opened = 0;
361 my $mcount_section = "__mcount_loc";
363 my $dirname;
364 my $filename;
365 my $prefix;
366 my $ext;
368 if ($inputfile =~ m,^(.*)/([^/]*)$,) {
369 $dirname = $1;
370 $filename = $2;
371 } else {
372 $dirname = ".";
373 $filename = $inputfile;
376 if ($filename =~ m,^(.*)(\.\S),) {
377 $prefix = $1;
378 $ext = $2;
379 } else {
380 $prefix = $filename;
381 $ext = "";
384 my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
385 my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
387 check_objcopy();
390 # Step 1: find all the local (static functions) and weak symbols.
391 # 't' is local, 'w/W' is weak
393 open (IN, "$nm $inputfile|") || die "error running $nm";
394 while (<IN>) {
395 if (/$local_regex/) {
396 $locals{$1} = 1;
397 } elsif (/$weak_regex/) {
398 $weak{$2} = $1;
401 close(IN);
403 my @offsets; # Array of offsets of mcount callers
404 my $ref_func; # reference function to use for offsets
405 my $offset = 0; # offset of ref_func to section beginning
408 # update_funcs - print out the current mcount callers
410 # Go through the list of offsets to callers and write them to
411 # the output file in a format that can be read by an assembler.
413 sub update_funcs
415 return unless ($ref_func and @offsets);
417 # Sanity check on weak function. A weak function may be overwritten by
418 # another function of the same name, making all these offsets incorrect.
419 if (defined $weak{$ref_func}) {
420 die "$inputfile: ERROR: referencing weak function" .
421 " $ref_func for mcount\n";
424 # is this function static? If so, note this fact.
425 if (defined $locals{$ref_func}) {
427 # only use locals if objcopy supports globalize-symbols
428 if (!$can_use_local) {
429 return;
431 $convert{$ref_func} = 1;
434 # Loop through all the mcount caller offsets and print a reference
435 # to the caller based from the ref_func.
436 if (!$opened) {
437 open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
438 $opened = 1;
439 print FILE "\t.section $mcount_section,\"a\",$section_type\n";
440 print FILE "\t.align $alignment\n" if (defined($alignment));
442 foreach my $cur_offset (@offsets) {
443 printf FILE "\t%s %s + %d\n", $type, $ref_func, $cur_offset - $offset;
448 # Step 2: find the sections and mcount call sites
450 open(IN, "$objdump -hdr $inputfile|") || die "error running $objdump";
452 my $text;
455 # read headers first
456 my $read_headers = 1;
458 while (<IN>) {
460 if ($read_headers && /$mcount_section/) {
462 # Somehow the make process can execute this script on an
463 # object twice. If it does, we would duplicate the mcount
464 # section and it will cause the function tracer self test
465 # to fail. Check if the mcount section exists, and if it does,
466 # warn and exit.
468 print STDERR "ERROR: $mcount_section already in $inputfile\n" .
469 "\tThis may be an indication that your build is corrupted.\n" .
470 "\tDelete $inputfile and try again. If the same object file\n" .
471 "\tstill causes an issue, then disable CONFIG_DYNAMIC_FTRACE.\n";
472 exit(-1);
475 # is it a section?
476 if (/$section_regex/) {
477 $read_headers = 0;
479 # Only record text sections that we know are safe
480 $read_function = defined($text_sections{$1});
481 # print out any recorded offsets
482 update_funcs();
484 # reset all markers and arrays
485 $text_found = 0;
486 undef($ref_func);
487 undef(@offsets);
489 # section found, now is this a start of a function?
490 } elsif ($read_function && /$function_regex/) {
491 $text_found = 1;
492 $text = $2;
494 # if this is either a local function or a weak function
495 # keep looking for functions that are global that
496 # we can use safely.
497 if (!defined($locals{$text}) && !defined($weak{$text})) {
498 $ref_func = $text;
499 $read_function = 0;
500 $offset = hex $1;
501 } else {
502 # if we already have a function, and this is weak, skip it
503 if (!defined($ref_func) && !defined($weak{$text}) &&
504 # PPC64 can have symbols that start with .L and
505 # gcc considers these special. Don't use them!
506 $text !~ /^\.L/) {
507 $ref_func = $text;
508 $offset = hex $1;
512 # is this a call site to mcount? If so, record it to print later
513 if ($text_found && /$mcount_regex/) {
514 push(@offsets, hex $1);
518 # dump out anymore offsets that may have been found
519 update_funcs();
521 # If we did not find any mcount callers, we are done (do nothing).
522 if (!$opened) {
523 exit(0);
526 close(FILE);
529 # Step 3: Compile the file that holds the list of call sites to mcount.
531 `$cc -o $mcount_o -c $mcount_s`;
533 my @converts = keys %convert;
536 # Step 4: Do we have sections that started with local functions?
538 if ($#converts >= 0) {
539 my $globallist = "";
540 my $locallist = "";
542 foreach my $con (@converts) {
543 $globallist .= " --globalize-symbol $con";
544 $locallist .= " --localize-symbol $con";
547 my $globalobj = $dirname . "/.tmp_gl_" . $filename;
548 my $globalmix = $dirname . "/.tmp_mx_" . $filename;
551 # Step 5: set up each local function as a global
553 `$objcopy $globallist $inputfile $globalobj`;
556 # Step 6: Link the global version to our list.
558 `$ld -r $globalobj $mcount_o -o $globalmix`;
561 # Step 7: Convert the local functions back into local symbols
563 `$objcopy $locallist $globalmix $inputfile`;
565 # Remove the temp files
566 `$rm $globalobj $globalmix`;
568 } else {
570 my $mix = $dirname . "/.tmp_mx_" . $filename;
573 # Step 8: Link the object with our list of call sites object.
575 `$ld -r $inputfile $mcount_o -o $mix`;
578 # Step 9: Move the result back to the original object.
580 `$mv $mix $inputfile`;
583 # Clean up the temp files
584 `$rm $mcount_o $mcount_s`;
586 exit(0);