linux-6.12.1/scripts/recordmcount.pl

2 # SPDX-License-Identifier: GPL-2.0-only
5 # recordmcount.pl - makes a section called __mcount_loc that holds
9 # What we want to end up with this is that each object file will have a
22 # functions in a section that has a call site to mcount, will have the
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
54 # offset from .sched.text. If we choose global symbol func2 as a reference and
58 #  .quad  func2 - 0x10
66 # in this section. In such a case we have to select a local one. E.g. func1:
83 # an undefined reference to func1 or a wrong reference to another global
87 # a way to make tmp.o reference the local objects of the original object
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.
95 # 1) Record all the local and weak symbols by using 'nm'
106 # 9) Move the result back to the original object.
120 	exit(1);
133      ".text" => 1,
134      ".init.text" => 1,
135      ".ref.text" => 1,
136      ".sched.text" => 1,
137      ".spinlock.text" => 1,
138      ".irqentry.text" => 1,
139      ".softirqentry.text" => 1,
140      ".kprobes.text" => 1,
141      ".cpuidle.text" => 1,
142      ".text.unlikely" => 1,
145 # Acceptable section-prefixes to record.
147      ".text." => 1,
150 # Note: we are nice to C-programmers here, thus we skip the '||='-idiom.
167 my $local_regex;	# Match a local function (return function)
168 my $weak_regex; 	# Match a weak function (return function)
169 my $section_regex;	# Find the start of a section
170 my $function_regex;	# Find the name of a function
189 $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
190 $weak_regex = "^[0-9a-fA-F]+\\s+([wW])\\s+(\\S+)";
192 $function_regex = "^([0-9a-fA-F]+)\\s+<([^^]*?)>:";
193 $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s(mcount|__fentry__)\$";
199     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s(mcount|__fentry__)([+-]0x[0-9a-zA-Z]+)?\$";
202     $mcount_adjust = -1;
205     $ld .= " -m elf_x86_64";
206     $objdump .= " -M x86-64";
207     $objcopy .= " -O elf64-x86-64";
208     $cc .= " -m64";
212     $mcount_adjust = -1;
215     $ld .= " -m elf_i386";
216     $objdump .= " -M i386";
217     $objcopy .= " -O elf32-i386";
218     $cc .= " -m32";
221     if ($cc =~ /-DCC_USING_HOTPATCH/) {
222 …$mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*c0 04 00 00 00 00\\s*(brcl\\s*0,|jgnop\\s*)[0-9a-f]+ <([^…
227     $ld .= " -m elf64_s390";
228     $cc .= " -m64";
234     $ld .= " -m shlelf_linux";
236 	$objcopy .= " -O elf32-shbig-linux";
238 	$objcopy .= " -O elf32-sh-linux";
244     $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
246     $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?\\w*?)>:";
247     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";
250 	    $cc .= " -mbig-endian ";
251 	    $ld .= " -EB ";
254 	    $cc .= " -mlittle-endian ";
255 	    $ld .= " -EL ";
260 	$cc .= " -m64 ";
261 	$ld .= " -m elf64".$ldemulation." ";
263 	$cc .= " -m32 ";
264 	$ld .= " -m elf32".$ldemulation." ";
270     $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24|THM_CALL)" .
276     $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_AARCH64_CALL26\\s+_mcount\$";
280     # 0000000000000000 <igmp_net_exit-0x18>:
288     $function_regex = "^([0-9a-fA-F]+)\\s+<(\\w*?)>:";
291     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
295     $ld .= " -m elf64_sparc";
296     $cc .= " -m64";
297     $objcopy .= " -O elf64-sparc";
299     # To enable module support, we need to enable the -mlong-calls option
303     # first one, and then we can replace this instruction by a branch
328 	    $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_26\\s+_mcount\$";
330 	    $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_HI16\\s+_mcount\$";
332     $objdump .= " -Melf-trad".$endian."mips ";
335 	    $endian = " -EB ";
336 	    $ld .= " -melf".$bits."btsmip";
338 	    $endian = " -EL ";
339 	    $ld .= " -melf".$bits."ltsmip";
342     $cc .= " -mno-abicalls -fno-pic -mabi=" . $bits . $endian;
347 		"^([0-9a-fA-F]+)\\s+<(.|[^\$]L.*?|\$[^L].*?|[^\$][^L].*?)>:";
352     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
354     $function_regex = "^([0-9a-fA-F]+)\\s+<([^.0-9][0-9a-zA-Z_\\.]+)>:";
355     $mcount_regex = "^\\s*([0-9a-fA-F]+):\\sR_RISCV_CALL(_PLT)?\\s_mcount\$";
359     $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_CKCORE_PCREL_JSR_IMM26BY2\\s+_mcount\$";
376     $dirname = $1;
384     $prefix = $1;
395 # Step 1: find all the local (static functions) and weak symbols.
401 	$locals{$1} = 1;
403 	$weak{$2} = $1;
413 # update_funcs - print out the current mcount callers
416 #  the output file in a format that can be read by an assembler.
422     # Sanity check on weak function. A weak function may be overwritten by
431 	$convert{$ref_func} = 1;
434     # Loop through all the mcount caller offsets and print a reference
438 	$opened = 1;
439 	print FILE "\t.section $mcount_section,\"a\",$section_type\n";
443 	printf FILE "\t%s %s + %d\n", $type, $ref_func, $cur_offset - $offset;
450 open(IN, "LC_ALL=C $objdump -hdr $inputfile|") || die "error running $objdump";
456 my $read_headers = 1;
472 	exit(-1);
475     # is it a section?
480 	$read_function = defined($text_sections{$1});
483 		if (substr($1, 0, length $prefix) eq $prefix) {
484 		    $read_function = 1;
497     # section found, now is this a start of a function?
499 	$text_found = 1;
502 	# if this is either a local function or a weak function
508 	    $offset = hex $1;
510 	    # if we already have a function, and this is weak, skip it
516 		$offset = hex $1;
520     # is this a call site to mcount? If so, record it to print later
522 	push(@offsets, (hex $1) + $mcount_adjust);
539 `$cc -o $mcount_o -c $mcount_s`;
551 	$globallist .= " --globalize-symbol $con";
552 	$locallist .= " --localize-symbol $con";
559     # Step 5: set up each local function as a global
566     `$ld -r $globalobj $mcount_o -o $globalmix`;
583     `$ld -r $inputfile $mcount_o -o $mix`;
586     # Step 9: Move the result back to the original object.