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
40 #        call mcount  (offset: 0x10)
44 #  func2:             (offset: 0x20)
50 #        call mcount (offset: 0x30)
54 # offset from .sched.text. If we choose global symbol func2 as a reference and
58 #  .quad  func2 - 0x10
59 #  .quad  func2 + 0x10
66 # in this section. In such a case we have to select a local one. E.g. func1:
71 #        call mcount  (offset: 0x10)
76 #        call mcount (offset: 0x20)
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.
106 # 9) Move the result back to the original object.
112 my $P = $0;
128     exit(0);
145 # Acceptable section-prefixes to record.
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__)\$";
195 $mcount_adjust = 0;
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]+ <([^…
223 	$mcount_adjust = 0;
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     $objcopy .= " -O elf64-sparc";
299     # To enable module support, we need to enable the -mlong-calls option
303     # first one, and then we can replace this instruction by a branch
308     #       c:	3c030000 	lui	v1,0x0
312     #      10:	64630000 	daddiu	v1,v1,0
322     #	  14:   0c000000        jal     0 <loongson_halt>
327     if ($is_module eq "0") {
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\$";
365 my $text_found = 0;
366 my $read_function = 0;
367 my $opened = 0;
410 my $offset = 0;		# offset of ref_func to section beginning
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
434     # Loop through all the mcount caller offsets and print a reference
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";
472 	exit(-1);
475     # is it a section?
477 	$read_headers = 0;
483 		if (substr($1, 0, length $prefix) eq $prefix) {
493 	$text_found = 0;
497     # section found, now is this a start of a function?
502 	# if this is either a local function or a weak function
507 	    $read_function = 0;
510 	    # if we already have a function, and this is weak, skip it
520     # is this a call site to mcount? If so, record it to print later
531     exit(0);
539 `$cc -o $mcount_o -c $mcount_s`;
546 if ($#converts >= 0) {
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.
594 exit(0);