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Steven Rostedt8da38212008-08-14 15:45:07 -04001#!/usr/bin/perl -w
2# (c) 2008, Steven Rostedt <srostedt@redhat.com>
3# Licensed under the terms of the GNU GPL License version 2
4#
5# recordmcount.pl - makes a section called __mcount_loc that holds
6# all the offsets to the calls to mcount.
7#
8#
Li Hongd49f6aa2009-10-28 13:01:38 +08009# 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.
Steven Rostedt8da38212008-08-14 15:45:07 -040016#
17# This is no easy feat. This script is called just after the original
18# object is compiled and before it is linked.
19#
Li Hongd49f6aa2009-10-28 13:01:38 +080020# 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.
Steven Rostedt8da38212008-08-14 15:45:07 -040025#
Li Hongd49f6aa2009-10-28 13:01:38 +080026# 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.
29#
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.
33#
Steven Rostedt8da38212008-08-14 15:45:07 -040034# e.g.
35#
Tim Abbott31b6e762009-04-30 20:06:11 -040036# .section ".sched.text", "ax"
Steven Rostedt8da38212008-08-14 15:45:07 -040037# [...]
Li Hongd49f6aa2009-10-28 13:01:38 +080038# func1:
39# [...]
40# call mcount (offset: 0x10)
Steven Rostedt8da38212008-08-14 15:45:07 -040041# [...]
42# ret
Li Hongd49f6aa2009-10-28 13:01:38 +080043# .globl fun2
44# func2: (offset: 0x20)
Steven Rostedt8da38212008-08-14 15:45:07 -040045# [...]
Li Hongd49f6aa2009-10-28 13:01:38 +080046# [...]
47# ret
48# func3:
49# [...]
50# call mcount (offset: 0x30)
Steven Rostedt8da38212008-08-14 15:45:07 -040051# [...]
52#
53# Both relocation offsets for the mcounts in the above example will be
Li Hongd49f6aa2009-10-28 13:01:38 +080054# 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:
Steven Rostedt8da38212008-08-14 15:45:07 -040056#
57# .section __mcount_loc
Li Hongd49f6aa2009-10-28 13:01:38 +080058# .quad func2 - 0x10
59# .quad func2 + 0x10
Steven Rostedt8da38212008-08-14 15:45:07 -040060#
Li Hongd49f6aa2009-10-28 13:01:38 +080061# We can then compile this tmp.s into tmp.o, and link it back to the original
Steven Rostedt8da38212008-08-14 15:45:07 -040062# object.
63#
Li Hongd49f6aa2009-10-28 13:01:38 +080064# 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:
Steven Rostedt8da38212008-08-14 15:45:07 -040067#
Tim Abbott31b6e762009-04-30 20:06:11 -040068# .section ".sched.text", "ax"
Li Hongd49f6aa2009-10-28 13:01:38 +080069# func1:
Steven Rostedt8da38212008-08-14 15:45:07 -040070# [...]
Li Hongd49f6aa2009-10-28 13:01:38 +080071# call mcount (offset: 0x10)
Steven Rostedt8da38212008-08-14 15:45:07 -040072# [...]
73# ret
Li Hongd49f6aa2009-10-28 13:01:38 +080074# func2:
Steven Rostedt8da38212008-08-14 15:45:07 -040075# [...]
Li Hongd49f6aa2009-10-28 13:01:38 +080076# call mcount (offset: 0x20)
Steven Rostedt8da38212008-08-14 15:45:07 -040077# [...]
Li Hongd49f6aa2009-10-28 13:01:38 +080078# .section "other.section"
Steven Rostedt8da38212008-08-14 15:45:07 -040079#
80# If we make the tmp.s the same as above, when we link together with
Li Hongd49f6aa2009-10-28 13:01:38 +080081# the original object, we will end up with two symbols for func1:
Steven Rostedt8da38212008-08-14 15:45:07 -040082# one local, one global. After final compile, we will end up with
Li Hongd49f6aa2009-10-28 13:01:38 +080083# an undefined reference to func1 or a wrong reference to another global
84# func1 in other files.
Steven Rostedt8da38212008-08-14 15:45:07 -040085#
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
Li Hongd49f6aa2009-10-28 13:01:38 +080088# file after it is linked together. To do this, we convert func1
Steven Rostedt8da38212008-08-14 15:45:07 -040089# into a global symbol before linking tmp.o. Then after we link tmp.o
Li Hongd49f6aa2009-10-28 13:01:38 +080090# 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.
Steven Rostedt8da38212008-08-14 15:45:07 -040092#
93# Here are the steps we take:
94#
Li Hong306dcf42009-10-28 13:06:19 +080095# 1) Record all the local and weak symbols by using 'nm'
Steven Rostedt8da38212008-08-14 15:45:07 -040096# 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.
Steven Rostedt8da38212008-08-14 15:45:07 -0400105# 8) Link the object with the list object.
106# 9) Move the result back to the original object.
Steven Rostedt8da38212008-08-14 15:45:07 -0400107#
108
109use strict;
110
111my $P = $0;
112$P =~ s@.*/@@g;
113
114my $V = '0.1';
115
Wu Zhangjine6299d22009-11-20 20:34:31 +0800116if ($#ARGV != 11) {
117 print "usage: $P arch endian bits objdump objcopy cc ld nm rm mv is_module inputfile\n";
Steven Rostedt8da38212008-08-14 15:45:07 -0400118 print "version: $V\n";
119 exit(1);
120}
121
Wu Zhangjine6299d22009-11-20 20:34:31 +0800122my ($arch, $endian, $bits, $objdump, $objcopy, $cc,
Shaohua Li18c167f2009-01-12 10:00:51 +0800123 $ld, $nm, $rm, $mv, $is_module, $inputfile) = @ARGV;
Steven Rostedt8da38212008-08-14 15:45:07 -0400124
Shaohua Li25aac9d2009-01-09 11:29:40 +0800125# This file refers to mcount and shouldn't be ftraced, so lets' ignore it
Li Hongbdd3b052009-10-28 13:03:32 +0800126if ($inputfile =~ m,kernel/trace/ftrace\.o$,) {
Shaohua Li25aac9d2009-01-09 11:29:40 +0800127 exit(0);
128}
129
Steven Rostedt34698bc2008-10-23 09:32:58 -0400130# Acceptable sections to record.
131my %text_sections = (
132 ".text" => 1,
Steven Rostedt1274a9c2011-02-11 16:43:33 -0500133 ".ref.text" => 1,
Liming Wangd144d5e2008-11-26 10:29:26 +0800134 ".sched.text" => 1,
135 ".spinlock.text" => 1,
Frederic Weisbeckera0343e82008-12-09 23:53:16 +0100136 ".irqentry.text" => 1,
Steven Rostedt9f087e72011-04-06 14:10:22 -0400137 ".kprobes.text" => 1,
Jiri Olsa4d828942009-10-13 16:33:54 -0400138 ".text.unlikely" => 1,
Steven Rostedt34698bc2008-10-23 09:32:58 -0400139);
140
Wolfram Sangdfaa9e22010-01-05 21:41:22 +0100141# Note: we are nice to C-programmers here, thus we skip the '||='-idiom.
142$objdump = 'objdump' if (!$objdump);
143$objcopy = 'objcopy' if (!$objcopy);
144$cc = 'gcc' if (!$cc);
145$ld = 'ld' if (!$ld);
146$nm = 'nm' if (!$nm);
147$rm = 'rm' if (!$rm);
148$mv = 'mv' if (!$mv);
Steven Rostedt8da38212008-08-14 15:45:07 -0400149
150#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
151# "'$nm' '$rm' '$mv' '$inputfile'\n";
152
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400153my %locals; # List of local (static) functions
154my %weak; # List of weak functions
155my %convert; # List of local functions used that needs conversion
Steven Rostedt8da38212008-08-14 15:45:07 -0400156
157my $type;
Li Hong306dcf42009-10-28 13:06:19 +0800158my $local_regex; # Match a local function (return function)
159my $weak_regex; # Match a weak function (return function)
Steven Rostedt8da38212008-08-14 15:45:07 -0400160my $section_regex; # Find the start of a section
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400161my $function_regex; # Find the name of a function
162 # (return offset and func name)
Steven Rostedt8da38212008-08-14 15:45:07 -0400163my $mcount_regex; # Find the call site to mcount (return offset)
Mike Frysinger465c6cc2010-08-06 03:26:24 -0400164my $mcount_adjust; # Address adjustment to mcount offset
Matt Fleming3a3d04a2008-11-20 21:49:52 +0000165my $alignment; # The .align value to use for $mcount_section
Jim Radforde58918a2008-11-20 19:48:39 -0800166my $section_type; # Section header plus possible alignment command
Li Hong7b7edc22009-10-28 13:04:21 +0800167my $can_use_local = 0; # If we can use local function references
168
Steven Rostedt638adb02009-11-17 10:48:25 -0500169# Shut up recordmcount if user has older objcopy
170my $quiet_recordmcount = ".tmp_quiet_recordmcount";
171my $print_warning = 1;
172$print_warning = 0 if ( -f $quiet_recordmcount);
173
Li Hong7b7edc22009-10-28 13:04:21 +0800174##
175# check_objcopy - whether objcopy supports --globalize-symbols
176#
177# --globalize-symbols came out in 2.17, we must test the version
178# of objcopy, and if it is less than 2.17, then we can not
179# record local functions.
180sub check_objcopy
181{
182 open (IN, "$objcopy --version |") or die "error running $objcopy";
183 while (<IN>) {
184 if (/objcopy.*\s(\d+)\.(\d+)/) {
185 $can_use_local = 1 if ($1 > 2 || ($1 == 2 && $2 >= 17));
186 last;
187 }
188 }
189 close (IN);
190
Steven Rostedt638adb02009-11-17 10:48:25 -0500191 if (!$can_use_local && $print_warning) {
Li Hong7b7edc22009-10-28 13:04:21 +0800192 print STDERR "WARNING: could not find objcopy version or version " .
193 "is less than 2.17.\n" .
Steven Rostedt638adb02009-11-17 10:48:25 -0500194 "\tLocal function references are disabled.\n";
195 open (QUIET, ">$quiet_recordmcount");
196 printf QUIET "Disables the warning from recordmcount.pl\n";
197 close QUIET;
Li Hong7b7edc22009-10-28 13:04:21 +0800198 }
199}
Steven Rostedt8da38212008-08-14 15:45:07 -0400200
Jan Kiszkab82a4042010-01-11 11:31:44 +0100201if ($arch =~ /(x86(_64)?)|(i386)/) {
Steven Rostedtdce9d182008-10-23 09:32:57 -0400202 if ($bits == 64) {
203 $arch = "x86_64";
204 } else {
205 $arch = "i386";
206 }
207}
208
Steven Rostedtc204f722008-11-20 15:07:34 -0500209#
210# We base the defaults off of i386, the other archs may
211# feel free to change them in the below if statements.
212#
Li Hong306dcf42009-10-28 13:06:19 +0800213$local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
214$weak_regex = "^[0-9a-fA-F]+\\s+([wW])\\s+(\\S+)";
Steven Rostedtc204f722008-11-20 15:07:34 -0500215$section_regex = "Disassembly of section\\s+(\\S+):";
216$function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
Jamie Ilesf02b6252013-11-05 10:42:09 +0000217$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s(mcount|__fentry__)\$";
Jim Radforde58918a2008-11-20 19:48:39 -0800218$section_type = '@progbits';
Mike Frysinger465c6cc2010-08-06 03:26:24 -0400219$mcount_adjust = 0;
Steven Rostedtc204f722008-11-20 15:07:34 -0500220$type = ".long";
221
Steven Rostedt8da38212008-08-14 15:45:07 -0400222if ($arch eq "x86_64") {
Jamie Ilesf02b6252013-11-05 10:42:09 +0000223 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s(mcount|__fentry__)([+-]0x[0-9a-zA-Z]+)?\$";
Steven Rostedt8da38212008-08-14 15:45:07 -0400224 $type = ".quad";
Matt Fleming7d5222a2008-11-07 13:26:25 +0000225 $alignment = 8;
Martin Schwidefsky521ccb52011-05-10 10:10:41 +0200226 $mcount_adjust = -1;
Steven Rostedtd74fcd12008-08-15 11:40:24 -0400227
228 # force flags for this arch
229 $ld .= " -m elf_x86_64";
230 $objdump .= " -M x86-64";
231 $objcopy .= " -O elf64-x86-64";
232 $cc .= " -m64";
233
Steven Rostedt8da38212008-08-14 15:45:07 -0400234} elsif ($arch eq "i386") {
Matt Fleming7d5222a2008-11-07 13:26:25 +0000235 $alignment = 4;
Martin Schwidefsky521ccb52011-05-10 10:10:41 +0200236 $mcount_adjust = -1;
Steven Rostedtd74fcd12008-08-15 11:40:24 -0400237
238 # force flags for this arch
239 $ld .= " -m elf_i386";
240 $objdump .= " -M i386";
241 $objcopy .= " -O elf32-i386";
242 $cc .= " -m32";
243
Heiko Carstensdfd9f7a2009-06-12 10:26:44 +0200244} elsif ($arch eq "s390" && $bits == 64) {
245 $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$";
Martin Schwidefskyf2963882011-05-10 10:10:43 +0200246 $mcount_adjust = -8;
Heiko Carstensdfd9f7a2009-06-12 10:26:44 +0200247 $alignment = 8;
248 $type = ".quad";
249 $ld .= " -m elf64_s390";
250 $cc .= " -m64";
251
Matt Fleming0da85c02008-11-12 20:11:47 +0900252} elsif ($arch eq "sh") {
Matt Fleming3a3d04a2008-11-20 21:49:52 +0000253 $alignment = 2;
Matt Fleming0da85c02008-11-12 20:11:47 +0900254
255 # force flags for this arch
256 $ld .= " -m shlelf_linux";
257 $objcopy .= " -O elf32-sh-linux";
258 $cc .= " -m32";
259
Steven Rostedt42e007d2008-11-20 07:16:16 -0800260} elsif ($arch eq "powerpc") {
Li Hong306dcf42009-10-28 13:06:19 +0800261 $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
Steven Rostedt42e007d2008-11-20 07:16:16 -0800262 $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?.*?)>:";
263 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";
Steven Rostedtc204f722008-11-20 15:07:34 -0500264
Steven Rostedt42e007d2008-11-20 07:16:16 -0800265 if ($bits == 64) {
266 $type = ".quad";
Steven Rostedt42e007d2008-11-20 07:16:16 -0800267 }
268
Jim Radforde58918a2008-11-20 19:48:39 -0800269} elsif ($arch eq "arm") {
270 $alignment = 2;
271 $section_type = '%progbits';
Rabin Vincent72dc43a2010-08-10 19:52:35 +0100272 $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24|THM_CALL)" .
Rabin Vincent3b6c2232010-08-10 19:43:28 +0100273 "\\s+(__gnu_mcount_nc|mcount)\$";
Jim Radforde58918a2008-11-20 19:48:39 -0800274
AKASHI Takahiroaf64d2a2014-04-30 10:54:32 +0100275} elsif ($arch eq "arm64") {
276 $alignment = 3;
277 $section_type = '%progbits';
278 $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_AARCH64_CALL26\\s+_mcount\$";
279 $type = ".quad";
Shaohua Li418071e2009-01-09 11:29:44 +0800280} elsif ($arch eq "ia64") {
281 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
282 $type = "data8";
283
284 if ($is_module eq "0") {
285 $cc .= " -mconstant-gp";
286 }
David S. Miller9be12f92009-06-13 01:03:24 -0700287} elsif ($arch eq "sparc64") {
288 # In the objdump output there are giblets like:
289 # 0000000000000000 <igmp_net_exit-0x18>:
290 # As there's some data blobs that get emitted into the
291 # text section before the first instructions and the first
292 # real symbols. We don't want to match that, so to combat
293 # this we use '\w' so we'll match just plain symbol names,
294 # and not those that also include hex offsets inside of the
295 # '<>' brackets. Actually the generic function_regex setting
296 # could safely use this too.
297 $function_regex = "^([0-9a-fA-F]+)\\s+<(\\w*?)>:";
298
299 # Sparc64 calls '_mcount' instead of plain 'mcount'.
300 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
301
302 $alignment = 8;
303 $type = ".xword";
304 $ld .= " -m elf64_sparc";
305 $cc .= " -m64";
306 $objcopy .= " -O elf64-sparc";
Wu Zhangjin538f1952009-11-20 20:34:32 +0800307} elsif ($arch eq "mips") {
308 # To enable module support, we need to enable the -mlong-calls option
309 # of gcc for module, after using this option, we can not get the real
310 # offset of the calling to _mcount, but the offset of the lui
311 # instruction or the addiu one. herein, we record the address of the
312 # first one, and then we can replace this instruction by a branch
313 # instruction to jump over the profiling function to filter the
314 # indicated functions, or swith back to the lui instruction to trace
315 # them, which means dynamic tracing.
316 #
317 # c: 3c030000 lui v1,0x0
318 # c: R_MIPS_HI16 _mcount
319 # c: R_MIPS_NONE *ABS*
320 # c: R_MIPS_NONE *ABS*
321 # 10: 64630000 daddiu v1,v1,0
322 # 10: R_MIPS_LO16 _mcount
323 # 10: R_MIPS_NONE *ABS*
324 # 10: R_MIPS_NONE *ABS*
325 # 14: 03e0082d move at,ra
326 # 18: 0060f809 jalr v1
327 #
328 # for the kernel:
329 #
330 # 10: 03e0082d move at,ra
331 # 14: 0c000000 jal 0 <loongson_halt>
332 # 14: R_MIPS_26 _mcount
333 # 14: R_MIPS_NONE *ABS*
334 # 14: R_MIPS_NONE *ABS*
335 # 18: 00020021 nop
336 if ($is_module eq "0") {
David Daneya484e542010-07-09 14:52:05 -0700337 $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_26\\s+_mcount\$";
Wu Zhangjin538f1952009-11-20 20:34:32 +0800338 } else {
339 $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_HI16\\s+_mcount\$";
340 }
341 $objdump .= " -Melf-trad".$endian."mips ";
342
343 if ($endian eq "big") {
344 $endian = " -EB ";
345 $ld .= " -melf".$bits."btsmip";
346 } else {
347 $endian = " -EL ";
348 $ld .= " -melf".$bits."ltsmip";
349 }
350
351 $cc .= " -mno-abicalls -fno-pic -mabi=" . $bits . $endian;
352 $ld .= $endian;
353
354 if ($bits == 64) {
355 $function_regex =
356 "^([0-9a-fA-F]+)\\s+<(.|[^\$]L.*?|\$[^L].*?|[^\$][^L].*?)>:";
357 $type = ".dword";
358 }
Michal Simek7d241ff2009-12-10 14:15:44 +0100359} elsif ($arch eq "microblaze") {
360 # Microblaze calls '_mcount' instead of plain 'mcount'.
361 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
Mike Frysinger465c6cc2010-08-06 03:26:24 -0400362} elsif ($arch eq "blackfin") {
363 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s__mcount\$";
364 $mcount_adjust = -4;
Tony Lu2d8eeda2013-12-05 15:36:54 -0500365} elsif ($arch eq "tilegx" || $arch eq "tile") {
366 # Default to the newer TILE-Gx architecture if only "tile" is given.
Tony Lua61fd5e2013-08-09 13:26:09 -0400367 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s__mcount\$";
368 $type = ".quad";
369 $alignment = 8;
Steven Rostedt8da38212008-08-14 15:45:07 -0400370} else {
371 die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
372}
373
374my $text_found = 0;
375my $read_function = 0;
376my $opened = 0;
Steven Rostedt8da38212008-08-14 15:45:07 -0400377my $mcount_section = "__mcount_loc";
378
379my $dirname;
380my $filename;
381my $prefix;
382my $ext;
383
384if ($inputfile =~ m,^(.*)/([^/]*)$,) {
385 $dirname = $1;
386 $filename = $2;
387} else {
388 $dirname = ".";
389 $filename = $inputfile;
390}
391
392if ($filename =~ m,^(.*)(\.\S),) {
393 $prefix = $1;
394 $ext = $2;
395} else {
396 $prefix = $filename;
397 $ext = "";
398}
399
400my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
401my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
402
Li Hong7b7edc22009-10-28 13:04:21 +0800403check_objcopy();
Steven Rostedtf2f84582008-08-25 14:52:11 -0400404
Steven Rostedtf2f84582008-08-25 14:52:11 -0400405#
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400406# Step 1: find all the local (static functions) and weak symbols.
Li Hong306dcf42009-10-28 13:06:19 +0800407# 't' is local, 'w/W' is weak
Steven Rostedt8da38212008-08-14 15:45:07 -0400408#
409open (IN, "$nm $inputfile|") || die "error running $nm";
410while (<IN>) {
Li Hong306dcf42009-10-28 13:06:19 +0800411 if (/$local_regex/) {
Steven Rostedt8da38212008-08-14 15:45:07 -0400412 $locals{$1} = 1;
Li Hong306dcf42009-10-28 13:06:19 +0800413 } elsif (/$weak_regex/) {
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400414 $weak{$2} = $1;
Steven Rostedt8da38212008-08-14 15:45:07 -0400415 }
416}
417close(IN);
418
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400419my @offsets; # Array of offsets of mcount callers
420my $ref_func; # reference function to use for offsets
421my $offset = 0; # offset of ref_func to section beginning
422
423##
424# update_funcs - print out the current mcount callers
425#
426# Go through the list of offsets to callers and write them to
427# the output file in a format that can be read by an assembler.
428#
429sub update_funcs
430{
Li Hong60928582009-10-28 13:07:03 +0800431 return unless ($ref_func and @offsets);
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400432
Li Hongc4b8ac22009-10-28 13:07:43 +0800433 # Sanity check on weak function. A weak function may be overwritten by
434 # another function of the same name, making all these offsets incorrect.
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400435 if (defined $weak{$ref_func}) {
Li Hongc4b8ac22009-10-28 13:07:43 +0800436 die "$inputfile: ERROR: referencing weak function" .
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400437 " $ref_func for mcount\n";
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400438 }
439
440 # is this function static? If so, note this fact.
441 if (defined $locals{$ref_func}) {
Steven Rostedtf2f84582008-08-25 14:52:11 -0400442
443 # only use locals if objcopy supports globalize-symbols
Li Hong7b7edc22009-10-28 13:04:21 +0800444 if (!$can_use_local) {
Steven Rostedtf2f84582008-08-25 14:52:11 -0400445 return;
446 }
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400447 $convert{$ref_func} = 1;
448 }
449
450 # Loop through all the mcount caller offsets and print a reference
451 # to the caller based from the ref_func.
Wolfram Sangdc4f8842010-01-05 19:27:51 +0100452 if (!$opened) {
453 open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
454 $opened = 1;
455 print FILE "\t.section $mcount_section,\"a\",$section_type\n";
456 print FILE "\t.align $alignment\n" if (defined($alignment));
457 }
458 foreach my $cur_offset (@offsets) {
459 printf FILE "\t%s %s + %d\n", $type, $ref_func, $cur_offset - $offset;
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400460 }
461}
462
Steven Rostedt8da38212008-08-14 15:45:07 -0400463#
464# Step 2: find the sections and mcount call sites
465#
Steven Rostedtb43f7092009-01-16 23:18:31 -0500466open(IN, "$objdump -hdr $inputfile|") || die "error running $objdump";
Steven Rostedt8da38212008-08-14 15:45:07 -0400467
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400468my $text;
469
Li Hongdb24c7d2009-10-28 13:05:23 +0800470
471# read headers first
Steven Rostedtb43f7092009-01-16 23:18:31 -0500472my $read_headers = 1;
473
Steven Rostedt8da38212008-08-14 15:45:07 -0400474while (<IN>) {
Li Hongdb24c7d2009-10-28 13:05:23 +0800475
476 if ($read_headers && /$mcount_section/) {
477 #
478 # Somehow the make process can execute this script on an
479 # object twice. If it does, we would duplicate the mcount
480 # section and it will cause the function tracer self test
481 # to fail. Check if the mcount section exists, and if it does,
482 # warn and exit.
483 #
484 print STDERR "ERROR: $mcount_section already in $inputfile\n" .
485 "\tThis may be an indication that your build is corrupted.\n" .
486 "\tDelete $inputfile and try again. If the same object file\n" .
487 "\tstill causes an issue, then disable CONFIG_DYNAMIC_FTRACE.\n";
488 exit(-1);
489 }
490
Steven Rostedt8da38212008-08-14 15:45:07 -0400491 # is it a section?
492 if (/$section_regex/) {
Steven Rostedtb43f7092009-01-16 23:18:31 -0500493 $read_headers = 0;
Steven Rostedt34698bc2008-10-23 09:32:58 -0400494
495 # Only record text sections that we know are safe
Wolfram Sangdfaa9e22010-01-05 21:41:22 +0100496 $read_function = defined($text_sections{$1});
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400497 # print out any recorded offsets
Li Hong60928582009-10-28 13:07:03 +0800498 update_funcs();
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400499
500 # reset all markers and arrays
Steven Rostedt8da38212008-08-14 15:45:07 -0400501 $text_found = 0;
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400502 undef($ref_func);
503 undef(@offsets);
504
Steven Rostedt8da38212008-08-14 15:45:07 -0400505 # section found, now is this a start of a function?
506 } elsif ($read_function && /$function_regex/) {
Steven Rostedt8da38212008-08-14 15:45:07 -0400507 $text_found = 1;
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400508 $text = $2;
509
510 # if this is either a local function or a weak function
511 # keep looking for functions that are global that
512 # we can use safely.
513 if (!defined($locals{$text}) && !defined($weak{$text})) {
514 $ref_func = $text;
515 $read_function = 0;
Matt Flemingbd171d52009-07-23 17:16:15 +0100516 $offset = hex $1;
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400517 } else {
518 # if we already have a function, and this is weak, skip it
Steven Rostedt3f6e9682009-08-05 22:00:14 -0400519 if (!defined($ref_func) && !defined($weak{$text}) &&
520 # PPC64 can have symbols that start with .L and
521 # gcc considers these special. Don't use them!
522 $text !~ /^\.L/) {
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400523 $ref_func = $text;
Matt Flemingbd171d52009-07-23 17:16:15 +0100524 $offset = hex $1;
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400525 }
Steven Rostedt8da38212008-08-14 15:45:07 -0400526 }
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400527 }
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400528 # is this a call site to mcount? If so, record it to print later
529 if ($text_found && /$mcount_regex/) {
Mike Frysinger465c6cc2010-08-06 03:26:24 -0400530 push(@offsets, (hex $1) + $mcount_adjust);
Steven Rostedt8da38212008-08-14 15:45:07 -0400531 }
532}
533
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400534# dump out anymore offsets that may have been found
Li Hong60928582009-10-28 13:07:03 +0800535update_funcs();
Steven Rostedt8feff1c2008-08-20 10:07:35 -0400536
Steven Rostedt8da38212008-08-14 15:45:07 -0400537# If we did not find any mcount callers, we are done (do nothing).
538if (!$opened) {
539 exit(0);
540}
541
542close(FILE);
543
544#
545# Step 3: Compile the file that holds the list of call sites to mcount.
546#
547`$cc -o $mcount_o -c $mcount_s`;
548
549my @converts = keys %convert;
550
551#
552# Step 4: Do we have sections that started with local functions?
553#
554if ($#converts >= 0) {
555 my $globallist = "";
556 my $locallist = "";
557
558 foreach my $con (@converts) {
559 $globallist .= " --globalize-symbol $con";
560 $locallist .= " --localize-symbol $con";
561 }
562
563 my $globalobj = $dirname . "/.tmp_gl_" . $filename;
564 my $globalmix = $dirname . "/.tmp_mx_" . $filename;
565
566 #
567 # Step 5: set up each local function as a global
568 #
569 `$objcopy $globallist $inputfile $globalobj`;
570
571 #
572 # Step 6: Link the global version to our list.
573 #
574 `$ld -r $globalobj $mcount_o -o $globalmix`;
575
576 #
577 # Step 7: Convert the local functions back into local symbols
578 #
579 `$objcopy $locallist $globalmix $inputfile`;
580
581 # Remove the temp files
582 `$rm $globalobj $globalmix`;
583
584} else {
585
586 my $mix = $dirname . "/.tmp_mx_" . $filename;
587
588 #
589 # Step 8: Link the object with our list of call sites object.
590 #
591 `$ld -r $inputfile $mcount_o -o $mix`;
592
593 #
594 # Step 9: Move the result back to the original object.
595 #
596 `$mv $mix $inputfile`;
597}
598
599# Clean up the temp files
600`$rm $mcount_o $mcount_s`;
601
602exit(0);