[deliverable/linux.git] / scripts / recordmcount.pl

#!/usr/bin/perl -w
# (c) 2008, Steven Rostedt <srostedt@redhat.com>
# Licensed under the terms of the GNU GPL License version 2
#
# recordmcount.pl - makes a section called __mcount_loc that holds
#                   all the offsets to the calls to mcount.
#
#
# What we want to end up with this is that each object file will have a
# section called __mcount_loc that will hold the list of pointers to mcount
# callers. After final linking, the vmlinux will have within .init.data the
# list of all callers to mcount between __start_mcount_loc and __stop_mcount_loc.
# Later on boot up, the kernel will read this list, save the locations and turn
# them into nops. When tracing or profiling is later enabled, these locations
# will then be converted back to pointers to some function.
#
# This is no easy feat. This script is called just after the original
# object is compiled and before it is linked.
#
# When parse this object file using 'objdump', the references to the call
# sites are offsets from the section that the call site is in. Hence, all
# functions in a section that has a call site to mcount, will have the
# offset from the beginning of the section and not the beginning of the
# function.
#
# But where this section will reside finally in vmlinx is undetermined at
# this point. So we can't use this kind of offsets to record the final
# address of this call site.
#
# The trick is to change the call offset referring the start of a section to
# referring a function symbol in this section. During the link step, 'ld' will
# compute the final address according to the information we record.
#
# e.g.
#
#  .section ".sched.text", "ax"
#        [...]
#  func1:
#        [...]
#        call mcount  (offset: 0x10)
#        [...]
#        ret
#  .globl fun2
#  func2:             (offset: 0x20)
#        [...]
#        [...]
#        ret
#  func3:
#        [...]
#        call mcount (offset: 0x30)
#        [...]
#
# Both relocation offsets for the mcounts in the above example will be
# offset from .sched.text. If we choose global symbol func2 as a reference and
# make another file called tmp.s with the new offsets:
#
#  .section __mcount_loc
#  .quad  func2 - 0x10
#  .quad  func2 + 0x10
#
# We can then compile this tmp.s into tmp.o, and link it back to the original
# object.
#
# In our algorithm, we will choose the first global function we meet in this
# section as the reference. But this gets hard if there is no global functions
# in this section. In such a case we have to select a local one. E.g. func1:
#
#  .section ".sched.text", "ax"
#  func1:
#        [...]
#        call mcount  (offset: 0x10)
#        [...]
#        ret
#  func2:
#        [...]
#        call mcount (offset: 0x20)
#        [...]
#  .section "other.section"
#
# If we make the tmp.s the same as above, when we link together with
# the original object, we will end up with two symbols for func1:
# one local, one global.  After final compile, we will end up with
# an undefined reference to func1 or a wrong reference to another global
# func1 in other files.
#
# Since local objects can reference local variables, we need to find
# a way to make tmp.o reference the local objects of the original object
# file after it is linked together. To do this, we convert func1
# into a global symbol before linking tmp.o. Then after we link tmp.o
# we will only have a single symbol for func1 that is global.
# We can convert func1 back into a local symbol and we are done.
#
# Here are the steps we take:
#
# 1) Record all the local and weak symbols by using 'nm'
# 2) Use objdump to find all the call site offsets and sections for
#    mcount.
# 3) Compile the list into its own object.
# 4) Do we have to deal with local functions? If not, go to step 8.
# 5) Make an object that converts these local functions to global symbols
#    with objcopy.
# 6) Link together this new object with the list object.
# 7) Convert the local functions back to local symbols and rename
#    the result as the original object.
# 8) Link the object with the list object.
# 9) Move the result back to the original object.
#

use strict;

my $P = $0;
$P =~ s@.*/@@g;

my $V = '0.1';

if ($#ARGV != 10) {
	print "usage: $P arch bits objdump objcopy cc ld nm rm mv is_module inputfile\n";
	print "version: $V\n";
	exit(1);
}

my ($arch, $bits, $objdump, $objcopy, $cc,
    $ld, $nm, $rm, $mv, $is_module, $inputfile) = @ARGV;

# This file refers to mcount and shouldn't be ftraced, so lets' ignore it
if ($inputfile =~ m,kernel/trace/ftrace\.o$,) {
    exit(0);
}

# Acceptable sections to record.
my %text_sections = (
     ".text" => 1,
     ".sched.text" => 1,
     ".spinlock.text" => 1,
     ".irqentry.text" => 1,
     ".text.unlikely" => 1,
);

$objdump = "objdump" if ((length $objdump) == 0);
$objcopy = "objcopy" if ((length $objcopy) == 0);
$cc = "gcc" if ((length $cc) == 0);
$ld = "ld" if ((length $ld) == 0);
$nm = "nm" if ((length $nm) == 0);
$rm = "rm" if ((length $rm) == 0);
$mv = "mv" if ((length $mv) == 0);

#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
#    "'$nm' '$rm' '$mv' '$inputfile'\n";

my %locals;		# List of local (static) functions
my %weak;		# List of weak functions
my %convert;		# List of local functions used that needs conversion

my $type;
my $local_regex;	# Match a local function (return function)
my $weak_regex; 	# Match a weak function (return function)
my $section_regex;	# Find the start of a section
my $function_regex;	# Find the name of a function
			#    (return offset and func name)
my $mcount_regex;	# Find the call site to mcount (return offset)
my $alignment;		# The .align value to use for $mcount_section
my $section_type;	# Section header plus possible alignment command
my $can_use_local = 0; 	# If we can use local function references

# Shut up recordmcount if user has older objcopy
my $quiet_recordmcount = ".tmp_quiet_recordmcount";
my $print_warning = 1;
$print_warning = 0 if ( -f $quiet_recordmcount);

##
# check_objcopy - whether objcopy supports --globalize-symbols
#
#  --globalize-symbols came out in 2.17, we must test the version
#  of objcopy, and if it is less than 2.17, then we can not
#  record local functions.
sub check_objcopy
{
    open (IN, "$objcopy --version |") or die "error running $objcopy";
    while (<IN>) {
	if (/objcopy.*\s(\d+)\.(\d+)/) {
	    $can_use_local = 1 if ($1 > 2 || ($1 == 2 && $2 >= 17));
	    last;
	}
    }
    close (IN);

    if (!$can_use_local && $print_warning) {
	print STDERR "WARNING: could not find objcopy version or version " .
	    "is less than 2.17.\n" .
	    "\tLocal function references are disabled.\n";
	open (QUIET, ">$quiet_recordmcount");
	printf QUIET "Disables the warning from recordmcount.pl\n";
	close QUIET;
    }
}

if ($arch eq "x86") {
    if ($bits == 64) {
	$arch = "x86_64";
    } else {
	$arch = "i386";
    }
}

#
# We base the defaults off of i386, the other archs may
# feel free to change them in the below if statements.
#
$local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
$weak_regex = "^[0-9a-fA-F]+\\s+([wW])\\s+(\\S+)";
$section_regex = "Disassembly of section\\s+(\\S+):";
$function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
$section_type = '@progbits';
$type = ".long";

if ($arch eq "x86_64") {
    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
    $type = ".quad";
    $alignment = 8;

    # force flags for this arch
    $ld .= " -m elf_x86_64";
    $objdump .= " -M x86-64";
    $objcopy .= " -O elf64-x86-64";
    $cc .= " -m64";

} elsif ($arch eq "i386") {
    $alignment = 4;

    # force flags for this arch
    $ld .= " -m elf_i386";
    $objdump .= " -M i386";
    $objcopy .= " -O elf32-i386";
    $cc .= " -m32";

} elsif ($arch eq "s390" && $bits == 32) {
    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_32\\s+_mcount\$";
    $alignment = 4;
    $ld .= " -m elf_s390";
    $cc .= " -m31";

} elsif ($arch eq "s390" && $bits == 64) {
    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$";
    $alignment = 8;
    $type = ".quad";
    $ld .= " -m elf64_s390";
    $cc .= " -m64";

} elsif ($arch eq "sh") {
    $alignment = 2;

    # force flags for this arch
    $ld .= " -m shlelf_linux";
    $objcopy .= " -O elf32-sh-linux";
    $cc .= " -m32";

} elsif ($arch eq "powerpc") {
    $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
    $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?.*?)>:";
    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";

    if ($bits == 64) {
	$type = ".quad";
    }

} elsif ($arch eq "arm") {
    $alignment = 2;
    $section_type = '%progbits';

} elsif ($arch eq "ia64") {
    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
    $type = "data8";

    if ($is_module eq "0") {
        $cc .= " -mconstant-gp";
    }
} elsif ($arch eq "sparc64") {
    # In the objdump output there are giblets like:
    # 0000000000000000 <igmp_net_exit-0x18>:
    # As there's some data blobs that get emitted into the
    # text section before the first instructions and the first
    # real symbols.  We don't want to match that, so to combat
    # this we use '\w' so we'll match just plain symbol names,
    # and not those that also include hex offsets inside of the
    # '<>' brackets.  Actually the generic function_regex setting
    # could safely use this too.
    $function_regex = "^([0-9a-fA-F]+)\\s+<(\\w*?)>:";

    # Sparc64 calls '_mcount' instead of plain 'mcount'.
    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";

    $alignment = 8;
    $type = ".xword";
    $ld .= " -m elf64_sparc";
    $cc .= " -m64";
    $objcopy .= " -O elf64-sparc";
} else {
    die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
}

my $text_found = 0;
my $read_function = 0;
my $opened = 0;
my $mcount_section = "__mcount_loc";

my $dirname;
my $filename;
my $prefix;
my $ext;

if ($inputfile =~ m,^(.*)/([^/]*)$,) {
    $dirname = $1;
    $filename = $2;
} else {
    $dirname = ".";
    $filename = $inputfile;
}

if ($filename =~ m,^(.*)(\.\S),) {
    $prefix = $1;
    $ext = $2;
} else {
    $prefix = $filename;
    $ext = "";
}

my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";

check_objcopy();

#
# Step 1: find all the local (static functions) and weak symbols.
#         't' is local, 'w/W' is weak
#
open (IN, "$nm $inputfile|") || die "error running $nm";
while (<IN>) {
    if (/$local_regex/) {
	$locals{$1} = 1;
    } elsif (/$weak_regex/) {
	$weak{$2} = $1;
    }
}
close(IN);

my @offsets;		# Array of offsets of mcount callers
my $ref_func;		# reference function to use for offsets
my $offset = 0;		# offset of ref_func to section beginning

##
# update_funcs - print out the current mcount callers
#
#  Go through the list of offsets to callers and write them to
#  the output file in a format that can be read by an assembler.
#
sub update_funcs
{
    return unless ($ref_func and @offsets);

    # Sanity check on weak function. A weak function may be overwritten by
    # another function of the same name, making all these offsets incorrect.
    if (defined $weak{$ref_func}) {
	die "$inputfile: ERROR: referencing weak function" .
	    " $ref_func for mcount\n";
    }

    # is this function static? If so, note this fact.
    if (defined $locals{$ref_func}) {

	# only use locals if objcopy supports globalize-symbols
	if (!$can_use_local) {
	    return;
	}
	$convert{$ref_func} = 1;
    }

    # Loop through all the mcount caller offsets and print a reference
    # to the caller based from the ref_func.
    for (my $i=0; $i <= $#offsets; $i++) {
	if (!$opened) {
	    open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
	    $opened = 1;
	    print FILE "\t.section $mcount_section,\"a\",$section_type\n";
	    print FILE "\t.align $alignment\n" if (defined($alignment));
	}
	printf FILE "\t%s %s + %d\n", $type, $ref_func, $offsets[$i] - $offset;
    }
}

#
# Step 2: find the sections and mcount call sites
#
open(IN, "$objdump -hdr $inputfile|") || die "error running $objdump";

my $text;


# read headers first
my $read_headers = 1;

while (<IN>) {

    if ($read_headers && /$mcount_section/) {
	#
	# Somehow the make process can execute this script on an
	# object twice. If it does, we would duplicate the mcount
	# section and it will cause the function tracer self test
	# to fail. Check if the mcount section exists, and if it does,
	# warn and exit.
	#
	print STDERR "ERROR: $mcount_section already in $inputfile\n" .
	    "\tThis may be an indication that your build is corrupted.\n" .
	    "\tDelete $inputfile and try again. If the same object file\n" .
	    "\tstill causes an issue, then disable CONFIG_DYNAMIC_FTRACE.\n";
	exit(-1);
    }

    # is it a section?
    if (/$section_regex/) {
	$read_headers = 0;

	# Only record text sections that we know are safe
	if (defined($text_sections{$1})) {
	    $read_function = 1;
	} else {
	    $read_function = 0;
	}
	# print out any recorded offsets
	update_funcs();

	# reset all markers and arrays
	$text_found = 0;
	undef($ref_func);
	undef(@offsets);

    # section found, now is this a start of a function?
    } elsif ($read_function && /$function_regex/) {
	$text_found = 1;
	$text = $2;

	# if this is either a local function or a weak function
	# keep looking for functions that are global that
	# we can use safely.
	if (!defined($locals{$text}) && !defined($weak{$text})) {
	    $ref_func = $text;
	    $read_function = 0;
	    $offset = hex $1;
	} else {
	    # if we already have a function, and this is weak, skip it
	    if (!defined($ref_func) && !defined($weak{$text}) &&
		 # PPC64 can have symbols that start with .L and
		 # gcc considers these special. Don't use them!
		 $text !~ /^\.L/) {
		$ref_func = $text;
		$offset = hex $1;
	    }
	}
    }
    # is this a call site to mcount? If so, record it to print later
    if ($text_found && /$mcount_regex/) {
	$offsets[$#offsets + 1] = hex $1;
    }
}

# dump out anymore offsets that may have been found
update_funcs();

# If we did not find any mcount callers, we are done (do nothing).
if (!$opened) {
    exit(0);
}

close(FILE);

#
# Step 3: Compile the file that holds the list of call sites to mcount.
#
`$cc -o $mcount_o -c $mcount_s`;

my @converts = keys %convert;

#
# Step 4: Do we have sections that started with local functions?
#
if ($#converts >= 0) {
    my $globallist = "";
    my $locallist = "";

    foreach my $con (@converts) {
	$globallist .= " --globalize-symbol $con";
	$locallist .= " --localize-symbol $con";
    }

    my $globalobj = $dirname . "/.tmp_gl_" . $filename;
    my $globalmix = $dirname . "/.tmp_mx_" . $filename;

    #
    # Step 5: set up each local function as a global
    #
    `$objcopy $globallist $inputfile $globalobj`;

    #
    # Step 6: Link the global version to our list.
    #
    `$ld -r $globalobj $mcount_o -o $globalmix`;

    #
    # Step 7: Convert the local functions back into local symbols
    #
    `$objcopy $locallist $globalmix $inputfile`;

    # Remove the temp files
    `$rm $globalobj $globalmix`;

} else {

    my $mix = $dirname . "/.tmp_mx_" . $filename;

    #
    # Step 8: Link the object with our list of call sites object.
    #
    `$ld -r $inputfile $mcount_o -o $mix`;

    #
    # Step 9: Move the result back to the original object.
    #
    `$mv $mix $inputfile`;
}

# Clean up the temp files
`$rm $mcount_o $mcount_s`;

exit(0);
Commit	Line	Data
	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
	4	#
	5	# recordmcount.pl - makes a section called __mcount_loc that holds
	6	# all the offsets to the calls to mcount.
	7	#
	8	#
	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.
	16	#
	17	# This is no easy feat. This script is called just after the original
	18	# object is compiled and before it is linked.
	19	#
	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.
	25	#
	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.
	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	#
	34	# e.g.
	35	#
	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	# [...]
	52	#
	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:
	56	#
	57	# .section __mcount_loc
	58	# .quad func2 - 0x10
	59	# .quad func2 + 0x10
	60	#
	61	# We can then compile this tmp.s into tmp.o, and link it back to the original
	62	# object.
	63	#
	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:
	67	#
	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"
	79	#
	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.
	85	#
	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.
	92	#
	93	# Here are the steps we take:
	94	#
	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.
	107	#
	108
	109	use strict;
	110
	111	my $P = $0;
	112	$P =~ s@.*/@@g;
	113
	114	my $V = '0.1';
	115
	116	if ($#ARGV != 10) {
	117	print "usage: $P arch bits objdump objcopy cc ld nm rm mv is_module inputfile\n";
	118	print "version: $V\n";
	119	exit(1);
	120	}
	121
	122	my ($arch, $bits, $objdump, $objcopy, $cc,
	123	$ld, $nm, $rm, $mv, $is_module, $inputfile) = @ARGV;
	124
	125	# This file refers to mcount and shouldn't be ftraced, so lets' ignore it
	126	if ($inputfile =~ m,kernel/trace/ftrace\.o$,) {
	127	exit(0);
	128	}
	129
	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,
	137	);
	138
	139	$objdump = "objdump" if ((length $objdump) == 0);
	140	$objcopy = "objcopy" if ((length $objcopy) == 0);
	141	$cc = "gcc" if ((length $cc) == 0);
	142	$ld = "ld" if ((length $ld) == 0);
	143	$nm = "nm" if ((length $nm) == 0);
	144	$rm = "rm" if ((length $rm) == 0);
	145	$mv = "mv" if ((length $mv) == 0);
	146
	147	#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
	148	# "'$nm' '$rm' '$mv' '$inputfile'\n";
	149
	150	my %locals; # List of local (static) functions
	151	my %weak; # List of weak functions
	152	my %convert; # List of local functions used that needs conversion
	153
	154	my $type;
	155	my $local_regex; # Match a local function (return function)
	156	my $weak_regex; # Match a weak function (return function)
	157	my $section_regex; # Find the start of a section
	158	my $function_regex; # Find the name of a function
	159	# (return offset and func name)
	160	my $mcount_regex; # Find the call site to mcount (return offset)
	161	my $alignment; # The .align value to use for $mcount_section
	162	my $section_type; # Section header plus possible alignment command
	163	my $can_use_local = 0; # If we can use local function references
	164
	165	# Shut up recordmcount if user has older objcopy
	166	my $quiet_recordmcount = ".tmp_quiet_recordmcount";
	167	my $print_warning = 1;
	168	$print_warning = 0 if ( -f $quiet_recordmcount);
	169
	170	##
	171	# check_objcopy - whether objcopy supports --globalize-symbols
	172	#
	173	# --globalize-symbols came out in 2.17, we must test the version
	174	# of objcopy, and if it is less than 2.17, then we can not
	175	# record local functions.
	176	sub check_objcopy
	177	{
	178	open (IN, "$objcopy --version \|") or die "error running $objcopy";
	179	while (<IN>) {
	180	if (/objcopy.*\s(\d+)\.(\d+)/) {
	181	$can_use_local = 1 if ($1 > 2 \|\| ($1 == 2 && $2 >= 17));
	182	last;
	183	}
	184	}
	185	close (IN);
	186
	187	if (!$can_use_local && $print_warning) {
	188	print STDERR "WARNING: could not find objcopy version or version " .
	189	"is less than 2.17.\n" .
	190	"\tLocal function references are disabled.\n";
	191	open (QUIET, ">$quiet_recordmcount");
	192	printf QUIET "Disables the warning from recordmcount.pl\n";
	193	close QUIET;
	194	}
	195	}
	196
	197	if ($arch eq "x86") {
	198	if ($bits == 64) {
	199	$arch = "x86_64";
	200	} else {
	201	$arch = "i386";
	202	}
	203	}
	204
	205	#
	206	# We base the defaults off of i386, the other archs may
	207	# feel free to change them in the below if statements.
	208	#
	209	$local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
	210	$weak_regex = "^[0-9a-fA-F]+\\s+([wW])\\s+(\\S+)";
	211	$section_regex = "Disassembly of section\\s+(\\S+):";
	212	$function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
	213	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\smcount\$";
	214	$section_type = '@progbits';
	215	$type = ".long";
	216
	217	if ($arch eq "x86_64") {
	218	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
	219	$type = ".quad";
	220	$alignment = 8;
	221
	222	# force flags for this arch
	223	$ld .= " -m elf_x86_64";
	224	$objdump .= " -M x86-64";
	225	$objcopy .= " -O elf64-x86-64";
	226	$cc .= " -m64";
	227
	228	} elsif ($arch eq "i386") {
	229	$alignment = 4;
	230
	231	# force flags for this arch
	232	$ld .= " -m elf_i386";
	233	$objdump .= " -M i386";
	234	$objcopy .= " -O elf32-i386";
	235	$cc .= " -m32";
	236
	237	} elsif ($arch eq "s390" && $bits == 32) {
	238	$mcount_regex = "^\\s([0-9a-fA-F]+):\\sR_390_32\\s+_mcount\$";
	239	$alignment = 4;
	240	$ld .= " -m elf_s390";
	241	$cc .= " -m31";
	242
	243	} elsif ($arch eq "s390" && $bits == 64) {
	244	$mcount_regex = "^\\s([0-9a-fA-F]+):\\sR_390_(PC\|PLT)32DBL\\s+_mcount\\+0x2\$";
	245	$alignment = 8;
	246	$type = ".quad";
	247	$ld .= " -m elf64_s390";
	248	$cc .= " -m64";
	249
	250	} elsif ($arch eq "sh") {
	251	$alignment = 2;
	252
	253	# force flags for this arch
	254	$ld .= " -m shlelf_linux";
	255	$objcopy .= " -O elf32-sh-linux";
	256	$cc .= " -m32";
	257
	258	} elsif ($arch eq "powerpc") {
	259	$local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
	260	$function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?.*?)>:";
	261	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\s\\.?_mcount\$";
	262
	263	if ($bits == 64) {
	264	$type = ".quad";
	265	}
	266
	267	} elsif ($arch eq "arm") {
	268	$alignment = 2;
	269	$section_type = '%progbits';
	270
	271	} elsif ($arch eq "ia64") {
	272	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\s_mcount\$";
	273	$type = "data8";
	274
	275	if ($is_module eq "0") {
	276	$cc .= " -mconstant-gp";
	277	}
	278	} elsif ($arch eq "sparc64") {
	279	# In the objdump output there are giblets like:
	280	# 0000000000000000 <igmp_net_exit-0x18>:
	281	# As there's some data blobs that get emitted into the
	282	# text section before the first instructions and the first
	283	# real symbols. We don't want to match that, so to combat
	284	# this we use '\w' so we'll match just plain symbol names,
	285	# and not those that also include hex offsets inside of the
	286	# '<>' brackets. Actually the generic function_regex setting
	287	# could safely use this too.
	288	$function_regex = "^([0-9a-fA-F]+)\\s+<(\\w*?)>:";
	289
	290	# Sparc64 calls '_mcount' instead of plain 'mcount'.
	291	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\s_mcount\$";
	292
	293	$alignment = 8;
	294	$type = ".xword";
	295	$ld .= " -m elf64_sparc";
	296	$cc .= " -m64";
	297	$objcopy .= " -O elf64-sparc";
	298	} else {
	299	die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
	300	}
	301
	302	my $text_found = 0;
	303	my $read_function = 0;
	304	my $opened = 0;
	305	my $mcount_section = "__mcount_loc";
	306
	307	my $dirname;
	308	my $filename;
	309	my $prefix;
	310	my $ext;
	311
	312	if ($inputfile =~ m,^(.)/([^/])$,) {
	313	$dirname = $1;
	314	$filename = $2;
	315	} else {
	316	$dirname = ".";
	317	$filename = $inputfile;
	318	}
	319
	320	if ($filename =~ m,^(.*)(\.\S),) {
	321	$prefix = $1;
	322	$ext = $2;
	323	} else {
	324	$prefix = $filename;
	325	$ext = "";
	326	}
	327
	328	my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
	329	my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
	330
	331	check_objcopy();
	332
	333	#
	334	# Step 1: find all the local (static functions) and weak symbols.
	335	# 't' is local, 'w/W' is weak
	336	#
	337	open (IN, "$nm $inputfile\|") \|\| die "error running $nm";
	338	while (<IN>) {
	339	if (/$local_regex/) {
	340	$locals{$1} = 1;
	341	} elsif (/$weak_regex/) {
	342	$weak{$2} = $1;
	343	}
	344	}
	345	close(IN);
	346
	347	my @offsets; # Array of offsets of mcount callers
	348	my $ref_func; # reference function to use for offsets
	349	my $offset = 0; # offset of ref_func to section beginning
	350
	351	##
	352	# update_funcs - print out the current mcount callers
	353	#
	354	# Go through the list of offsets to callers and write them to
	355	# the output file in a format that can be read by an assembler.
	356	#
	357	sub update_funcs
	358	{
	359	return unless ($ref_func and @offsets);
	360
	361	# Sanity check on weak function. A weak function may be overwritten by
	362	# another function of the same name, making all these offsets incorrect.
	363	if (defined $weak{$ref_func}) {
	364	die "$inputfile: ERROR: referencing weak function" .
	365	" $ref_func for mcount\n";
	366	}
	367
	368	# is this function static? If so, note this fact.
	369	if (defined $locals{$ref_func}) {
	370
	371	# only use locals if objcopy supports globalize-symbols
	372	if (!$can_use_local) {
	373	return;
	374	}
	375	$convert{$ref_func} = 1;
	376	}
	377
	378	# Loop through all the mcount caller offsets and print a reference
	379	# to the caller based from the ref_func.
	380	for (my $i=0; $i <= $#offsets; $i++) {
	381	if (!$opened) {
	382	open(FILE, ">$mcount_s") \|\| die "can't create $mcount_s\n";
	383	$opened = 1;
	384	print FILE "\t.section $mcount_section,\"a\",$section_type\n";
	385	print FILE "\t.align $alignment\n" if (defined($alignment));
	386	}
	387	printf FILE "\t%s %s + %d\n", $type, $ref_func, $offsets[$i] - $offset;
	388	}
	389	}
	390
	391	#
	392	# Step 2: find the sections and mcount call sites
	393	#
	394	open(IN, "$objdump -hdr $inputfile\|") \|\| die "error running $objdump";
	395
	396	my $text;
	397
	398
	399	# read headers first
	400	my $read_headers = 1;
	401
	402	while (<IN>) {
	403
	404	if ($read_headers && /$mcount_section/) {
	405	#
	406	# Somehow the make process can execute this script on an
	407	# object twice. If it does, we would duplicate the mcount
	408	# section and it will cause the function tracer self test
	409	# to fail. Check if the mcount section exists, and if it does,
	410	# warn and exit.
	411	#
	412	print STDERR "ERROR: $mcount_section already in $inputfile\n" .
	413	"\tThis may be an indication that your build is corrupted.\n" .
	414	"\tDelete $inputfile and try again. If the same object file\n" .
	415	"\tstill causes an issue, then disable CONFIG_DYNAMIC_FTRACE.\n";
	416	exit(-1);
	417	}
	418
	419	# is it a section?
	420	if (/$section_regex/) {
	421	$read_headers = 0;
	422
	423	# Only record text sections that we know are safe
	424	if (defined($text_sections{$1})) {
	425	$read_function = 1;
	426	} else {
	427	$read_function = 0;
	428	}
	429	# print out any recorded offsets
	430	update_funcs();
	431
	432	# reset all markers and arrays
	433	$text_found = 0;
	434	undef($ref_func);
	435	undef(@offsets);
	436
	437	# section found, now is this a start of a function?
	438	} elsif ($read_function && /$function_regex/) {
	439	$text_found = 1;
	440	$text = $2;
	441
	442	# if this is either a local function or a weak function
	443	# keep looking for functions that are global that
	444	# we can use safely.
	445	if (!defined($locals{$text}) && !defined($weak{$text})) {
	446	$ref_func = $text;
	447	$read_function = 0;
	448	$offset = hex $1;
	449	} else {
	450	# if we already have a function, and this is weak, skip it
	451	if (!defined($ref_func) && !defined($weak{$text}) &&
	452	# PPC64 can have symbols that start with .L and
	453	# gcc considers these special. Don't use them!
	454	$text !~ /^\.L/) {
	455	$ref_func = $text;
	456	$offset = hex $1;
	457	}
	458	}
	459	}
	460	# is this a call site to mcount? If so, record it to print later
	461	if ($text_found && /$mcount_regex/) {
	462	$offsets[$#offsets + 1] = hex $1;
	463	}
	464	}
	465
	466	# dump out anymore offsets that may have been found
	467	update_funcs();
	468
	469	# If we did not find any mcount callers, we are done (do nothing).
	470	if (!$opened) {
	471	exit(0);
	472	}
	473
	474	close(FILE);
	475
	476	#
	477	# Step 3: Compile the file that holds the list of call sites to mcount.
	478	#
	479	`$cc -o $mcount_o -c $mcount_s`;
	480
	481	my @converts = keys %convert;
	482
	483	#
	484	# Step 4: Do we have sections that started with local functions?
	485	#
	486	if ($#converts >= 0) {
	487	my $globallist = "";
	488	my $locallist = "";
	489
	490	foreach my $con (@converts) {
	491	$globallist .= " --globalize-symbol $con";
	492	$locallist .= " --localize-symbol $con";
	493	}
	494
	495	my $globalobj = $dirname . "/.tmp_gl_" . $filename;
	496	my $globalmix = $dirname . "/.tmp_mx_" . $filename;
	497
	498	#
	499	# Step 5: set up each local function as a global
	500	#
	501	`$objcopy $globallist $inputfile $globalobj`;
	502
	503	#
	504	# Step 6: Link the global version to our list.
	505	#
	506	`$ld -r $globalobj $mcount_o -o $globalmix`;
	507
	508	#
	509	# Step 7: Convert the local functions back into local symbols
	510	#
	511	`$objcopy $locallist $globalmix $inputfile`;
	512
	513	# Remove the temp files
	514	`$rm $globalobj $globalmix`;
	515
	516	} else {
	517
	518	my $mix = $dirname . "/.tmp_mx_" . $filename;
	519
	520	#
	521	# Step 8: Link the object with our list of call sites object.
	522	#
	523	`$ld -r $inputfile $mcount_o -o $mix`;
	524
	525	#
	526	# Step 9: Move the result back to the original object.
	527	#
	528	`$mv $mix $inputfile`;
	529	}
	530
	531	# Clean up the temp files
	532	`$rm $mcount_o $mcount_s`;
	533
	534	exit(0);