[net-next-2.6.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 is a section in vmlinux called
# __mcount_loc that contains a list of pointers to all the
# call sites in the kernel that call mcount. 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.
#
# The references to the call sites are offsets from the section of text
# 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.
#
# The trick is to find a way to record the beginning of the section.
# The way we do this is to look at the first function in the section
# which will also be the location of that section after final link.
# e.g.
#
#  .section ".sched.text", "ax"
#  .globl my_func
#  my_func:
#        [...]
#        call mcount  (offset: 0x5)
#        [...]
#        ret
#  other_func:
#        [...]
#        call mcount (offset: 0x1b)
#        [...]
#
# Both relocation offsets for the mcounts in the above example will be
# offset from .sched.text. If we make another file called tmp.s with:
#
#  .section __mcount_loc
#  .quad  my_func + 0x5
#  .quad  my_func + 0x1b
#
# We can then compile this tmp.s into tmp.o, and link it to the original
# object.
#
# But this gets hard if my_func is not globl (a static function).
# In such a case we have:
#
#  .section ".sched.text", "ax"
#  my_func:
#        [...]
#        call mcount  (offset: 0x5)
#        [...]
#        ret
#  other_func:
#        [...]
#        call mcount (offset: 0x1b)
#        [...]
#
# 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 my_func:
# one local, one global.  After final compile, we will end up with
# an undefined reference to my_func.
#
# 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 the my_func
# into a global symbol before linking tmp.o. Then after we link tmp.o
# we will only have a single symbol for my_func that is global.
# We can convert my_func back into a local symbol and we are done.
#
# Here are the steps we take:
#
# 1) Record all the local 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.
#    End.
# 8) Link the object with the list object.
# 9) Move the result back to the original object.
#    End.
#

use strict;

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

my $V = '0.1';

if ($#ARGV < 7) {
	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 eq "kernel/trace/ftrace.o") {
    exit(0);
}

# Acceptable sections to record.
my %text_sections = (
     ".text" => 1,
     ".sched.text" => 1,
     ".spinlock.text" => 1,
     ".irqentry.text" => 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 $nm_regex;		# Find the local functions (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

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.
#
$nm_regex = "^[0-9a-fA-F]+\\s+t\\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") {
    $nm_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";

#
# --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.
my $use_locals = 01;
my $local_warn_once = 0;
my $found_version = 0;

open (IN, "$objcopy --version |") || die "error running $objcopy";
while (<IN>) {
    if (/objcopy.*\s(\d+)\.(\d+)/) {
	my $major = $1;
	my $minor = $2;

	$found_version = 1;
	if ($major < 2 ||
	    ($major == 2 && $minor < 17)) {
	    $use_locals = 0;
	}
	last;
    }
}
close (IN);

if (!$found_version) {
    print STDERR "WARNING: could not find objcopy version.\n" .
	"\tDisabling local function references.\n";
}

#
# Step 1: find all the local (static functions) and weak symbols.
#        't' is local, 'w/W' is weak (we never use a weak function)
#
open (IN, "$nm $inputfile|") || die "error running $nm";
while (<IN>) {
    if (/$nm_regex/) {
	$locals{$1} = 1;
    } elsif (/^[0-9a-fA-F]+\s+([wW])\s+(\S+)/) {
	$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 if ($#offsets < 0);

    defined($ref_func) || die "No function to reference";

    # A section only had a weak function, to represent it.
    # Unfortunately, a weak function may be overwritten by another
    # function of the same name, making all these offsets incorrect.
    # To be safe, we simply print a warning and bail.
    if (defined $weak{$ref_func}) {
	print STDERR
	    "$inputfile: WARNING: referencing weak function" .
	    " $ref_func for mcount\n";
	return;
    }

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

	# only use locals if objcopy supports globalize-symbols
	if (!$use_locals) {
	    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;

my $read_headers = 1;

while (<IN>) {
    # 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 {
	    $read_function = 0;
	}
	# print out any recorded offsets
	update_funcs() if (defined($ref_func));

	# 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 $1;
	    }
	}
    } elsif ($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 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 (defined($ref_func));

# 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
8da3821b SR	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 is a section in vmlinux called
	10	# __mcount_loc that contains a list of pointers to all the
	11	# call sites in the kernel that call mcount. Later on boot up, the kernel
	12	# will read this list, save the locations and turn them into nops.
	13	# When tracing or profiling is later enabled, these locations will then
	14	# be converted back to pointers to some function.
	15	#
	16	# This is no easy feat. This script is called just after the original
	17	# object is compiled and before it is linked.
	18	#
	19	# The references to the call sites are offsets from the section of text
	20	# that the call site is in. Hence, all functions in a section that
	21	# has a call site to mcount, will have the offset from the beginning of
	22	# the section and not the beginning of the function.
	23	#
	24	# The trick is to find a way to record the beginning of the section.
	25	# The way we do this is to look at the first function in the section
	26	# which will also be the location of that section after final link.
	27	# e.g.
	28	#
31b6e76e	29	# .section ".sched.text", "ax"
8da3821b SR	30	# .globl my_func
	31	# my_func:
	32	# [...]
	33	# call mcount (offset: 0x5)
	34	# [...]
	35	# ret
	36	# other_func:
	37	# [...]
	38	# call mcount (offset: 0x1b)
	39	# [...]
	40	#
	41	# Both relocation offsets for the mcounts in the above example will be
31b6e76e	42	# offset from .sched.text. If we make another file called tmp.s with:
8da3821b SR	43	#
	44	# .section __mcount_loc
	45	# .quad my_func + 0x5
	46	# .quad my_func + 0x1b
	47	#
	48	# We can then compile this tmp.s into tmp.o, and link it to the original
	49	# object.
	50	#
	51	# But this gets hard if my_func is not globl (a static function).
	52	# In such a case we have:
	53	#
31b6e76e	54	# .section ".sched.text", "ax"
8da3821b SR	55	# my_func:
	56	# [...]
	57	# call mcount (offset: 0x5)
	58	# [...]
	59	# ret
8da3821b SR	60	# other_func:
	61	# [...]
	62	# call mcount (offset: 0x1b)
	63	# [...]
	64	#
	65	# If we make the tmp.s the same as above, when we link together with
	66	# the original object, we will end up with two symbols for my_func:
	67	# one local, one global. After final compile, we will end up with
	68	# an undefined reference to my_func.
	69	#
	70	# Since local objects can reference local variables, we need to find
	71	# a way to make tmp.o reference the local objects of the original object
	72	# file after it is linked together. To do this, we convert the my_func
	73	# into a global symbol before linking tmp.o. Then after we link tmp.o
	74	# we will only have a single symbol for my_func that is global.
	75	# We can convert my_func back into a local symbol and we are done.
	76	#
	77	# Here are the steps we take:
	78	#
	79	# 1) Record all the local symbols by using 'nm'
	80	# 2) Use objdump to find all the call site offsets and sections for
	81	# mcount.
	82	# 3) Compile the list into its own object.
	83	# 4) Do we have to deal with local functions? If not, go to step 8.
	84	# 5) Make an object that converts these local functions to global symbols
	85	# with objcopy.
	86	# 6) Link together this new object with the list object.
	87	# 7) Convert the local functions back to local symbols and rename
	88	# the result as the original object.
	89	# End.
	90	# 8) Link the object with the list object.
	91	# 9) Move the result back to the original object.
	92	# End.
	93	#
	94
	95	use strict;
	96
	97	my $P = $0;
	98	$P =~ s@.*/@@g;
	99
	100	my $V = '0.1';
	101
18c167fd	102	if ($#ARGV < 7) {
b43f7093	103	print "usage: $P arch bits objdump objcopy cc ld nm rm mv is_module inputfile\n";
8da3821b SR	104	print "version: $V\n";
	105	exit(1);
	106	}
	107
dce9d18a	108	my ($arch, $bits, $objdump, $objcopy, $cc,
18c167fd	109	$ld, $nm, $rm, $mv, $is_module, $inputfile) = @ARGV;
8da3821b	110
25aac9dc SL	111	# This file refers to mcount and shouldn't be ftraced, so lets' ignore it
	112	if ($inputfile eq "kernel/trace/ftrace.o") {
	113	exit(0);
	114	}
	115
34698bcb SR	116	# Acceptable sections to record.
	117	my %text_sections = (
	118	".text" => 1,
d144d5ee LW	119	".sched.text" => 1,
d144d5ee LW	120	".spinlock.text" => 1,
a0343e82	121	".irqentry.text" => 1,
34698bcb SR	122	);
34698bcb SR	123
8da3821b SR	124	$objdump = "objdump" if ((length $objdump) == 0);
	125	$objcopy = "objcopy" if ((length $objcopy) == 0);
	126	$cc = "gcc" if ((length $cc) == 0);
	127	$ld = "ld" if ((length $ld) == 0);
	128	$nm = "nm" if ((length $nm) == 0);
	129	$rm = "rm" if ((length $rm) == 0);
	130	$mv = "mv" if ((length $mv) == 0);
	131
	132	#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
	133	# "'$nm' '$rm' '$mv' '$inputfile'\n";
	134
8feff1ca SR	135	my %locals; # List of local (static) functions
	136	my %weak; # List of weak functions
	137	my %convert; # List of local functions used that needs conversion
8da3821b SR	138
8da3821b SR	139	my $type;
42e007d0	140	my $nm_regex; # Find the local functions (return function)
8da3821b	141	my $section_regex; # Find the start of a section
8feff1ca SR	142	my $function_regex; # Find the name of a function
8feff1ca SR	143	# (return offset and func name)
8da3821b	144	my $mcount_regex; # Find the call site to mcount (return offset)
3a3d04ae	145	my $alignment; # The .align value to use for $mcount_section
e58918ab	146	my $section_type; # Section header plus possible alignment command
8da3821b	147
dce9d18a SR	148	if ($arch eq "x86") {
	149	if ($bits == 64) {
	150	$arch = "x86_64";
	151	} else {
	152	$arch = "i386";
	153	}
	154	}
	155
c204f726 SR	156	#
	157	# We base the defaults off of i386, the other archs may
	158	# feel free to change them in the below if statements.
	159	#
	160	$nm_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
	161	$section_regex = "Disassembly of section\\s+(\\S+):";
	162	$function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
	163	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\smcount\$";
e58918ab	164	$section_type = '@progbits';
c204f726 SR	165	$type = ".long";
c204f726 SR	166
8da3821b	167	if ($arch eq "x86_64") {
8da3821b SR	168	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
8da3821b SR	169	$type = ".quad";
7d5222a6	170	$alignment = 8;
d74fcd1e SR	171
	172	# force flags for this arch
	173	$ld .= " -m elf_x86_64";
	174	$objdump .= " -M x86-64";
	175	$objcopy .= " -O elf64-x86-64";
	176	$cc .= " -m64";
	177
8da3821b	178	} elsif ($arch eq "i386") {
7d5222a6	179	$alignment = 4;
d74fcd1e SR	180
	181	# force flags for this arch
	182	$ld .= " -m elf_i386";
	183	$objdump .= " -M i386";
	184	$objcopy .= " -O elf32-i386";
	185	$cc .= " -m32";
	186
dfd9f7ab HC	187	} elsif ($arch eq "s390" && $bits == 32) {
	188	$mcount_regex = "^\\s([0-9a-fA-F]+):\\sR_390_32\\s+_mcount\$";
	189	$alignment = 4;
	190	$ld .= " -m elf_s390";
	191	$cc .= " -m31";
	192
	193	} elsif ($arch eq "s390" && $bits == 64) {
	194	$mcount_regex = "^\\s([0-9a-fA-F]+):\\sR_390_(PC\|PLT)32DBL\\s+_mcount\\+0x2\$";
	195	$alignment = 8;
	196	$type = ".quad";
	197	$ld .= " -m elf64_s390";
	198	$cc .= " -m64";
	199
0da85c09	200	} elsif ($arch eq "sh") {
3a3d04ae	201	$alignment = 2;
0da85c09 MF	202
	203	# force flags for this arch
	204	$ld .= " -m shlelf_linux";
	205	$objcopy .= " -O elf32-sh-linux";
	206	$cc .= " -m32";
	207
42e007d0 SR	208	} elsif ($arch eq "powerpc") {
42e007d0 SR	209	$nm_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
42e007d0 SR	210	$function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?.*?)>:";
42e007d0 SR	211	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\s\\.?_mcount\$";
c204f726	212
42e007d0 SR	213	if ($bits == 64) {
42e007d0 SR	214	$type = ".quad";
42e007d0 SR	215	}
42e007d0 SR	216
e58918ab JR	217	} elsif ($arch eq "arm") {
	218	$alignment = 2;
	219	$section_type = '%progbits';
	220
418071eb SL	221	} elsif ($arch eq "ia64") {
	222	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\s_mcount\$";
	223	$type = "data8";
	224
	225	if ($is_module eq "0") {
	226	$cc .= " -mconstant-gp";
	227	}
9be12f9b DM	228	} elsif ($arch eq "sparc64") {
	229	# In the objdump output there are giblets like:
	230	# 0000000000000000 <igmp_net_exit-0x18>:
	231	# As there's some data blobs that get emitted into the
	232	# text section before the first instructions and the first
	233	# real symbols. We don't want to match that, so to combat
	234	# this we use '\w' so we'll match just plain symbol names,
	235	# and not those that also include hex offsets inside of the
	236	# '<>' brackets. Actually the generic function_regex setting
	237	# could safely use this too.
	238	$function_regex = "^([0-9a-fA-F]+)\\s+<(\\w*?)>:";
	239
	240	# Sparc64 calls '_mcount' instead of plain 'mcount'.
	241	$mcount_regex = "^\\s([0-9a-fA-F]+):.\\s_mcount\$";
	242
	243	$alignment = 8;
	244	$type = ".xword";
	245	$ld .= " -m elf64_sparc";
	246	$cc .= " -m64";
	247	$objcopy .= " -O elf64-sparc";
8da3821b SR	248	} else {
	249	die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
	250	}
	251
	252	my $text_found = 0;
	253	my $read_function = 0;
	254	my $opened = 0;
8da3821b SR	255	my $mcount_section = "__mcount_loc";
	256
	257	my $dirname;
	258	my $filename;
	259	my $prefix;
	260	my $ext;
	261
	262	if ($inputfile =~ m,^(.)/([^/])$,) {
	263	$dirname = $1;
	264	$filename = $2;
	265	} else {
	266	$dirname = ".";
	267	$filename = $inputfile;
	268	}
	269
	270	if ($filename =~ m,^(.*)(\.\S),) {
	271	$prefix = $1;
	272	$ext = $2;
	273	} else {
	274	$prefix = $filename;
	275	$ext = "";
	276	}
	277
	278	my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
	279	my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
	280
f2f8458e SR	281	#
	282	# --globalize-symbols came out in 2.17, we must test the version
	283	# of objcopy, and if it is less than 2.17, then we can not
	284	# record local functions.
	285	my $use_locals = 01;
	286	my $local_warn_once = 0;
	287	my $found_version = 0;
	288
	289	open (IN, "$objcopy --version \|") \|\| die "error running $objcopy";
	290	while (<IN>) {
	291	if (/objcopy.*\s(\d+)\.(\d+)/) {
	292	my $major = $1;
	293	my $minor = $2;
	294
	295	$found_version = 1;
	296	if ($major < 2 \|\|
	297	($major == 2 && $minor < 17)) {
	298	$use_locals = 0;
	299	}
	300	last;
	301	}
	302	}
	303	close (IN);
	304
	305	if (!$found_version) {
	306	print STDERR "WARNING: could not find objcopy version.\n" .
	307	"\tDisabling local function references.\n";
	308	}
	309
8da3821b	310	#
8feff1ca SR	311	# Step 1: find all the local (static functions) and weak symbols.
8feff1ca SR	312	# 't' is local, 'w/W' is weak (we never use a weak function)
8da3821b SR	313	#
	314	open (IN, "$nm $inputfile\|") \|\| die "error running $nm";
	315	while (<IN>) {
42e007d0	316	if (/$nm_regex/) {
8da3821b	317	$locals{$1} = 1;
8feff1ca SR	318	} elsif (/^[0-9a-fA-F]+\s+([wW])\s+(\S+)/) {
8feff1ca SR	319	$weak{$2} = $1;
8da3821b SR	320	}
	321	}
	322	close(IN);
	323
8feff1ca SR	324	my @offsets; # Array of offsets of mcount callers
	325	my $ref_func; # reference function to use for offsets
	326	my $offset = 0; # offset of ref_func to section beginning
	327
	328	##
	329	# update_funcs - print out the current mcount callers
	330	#
	331	# Go through the list of offsets to callers and write them to
	332	# the output file in a format that can be read by an assembler.
	333	#
	334	sub update_funcs
	335	{
	336	return if ($#offsets < 0);
	337
	338	defined($ref_func) \|\| die "No function to reference";
	339
	340	# A section only had a weak function, to represent it.
	341	# Unfortunately, a weak function may be overwritten by another
	342	# function of the same name, making all these offsets incorrect.
	343	# To be safe, we simply print a warning and bail.
	344	if (defined $weak{$ref_func}) {
	345	print STDERR
	346	"$inputfile: WARNING: referencing weak function" .
	347	" $ref_func for mcount\n";
	348	return;
	349	}
	350
	351	# is this function static? If so, note this fact.
	352	if (defined $locals{$ref_func}) {
f2f8458e SR	353
	354	# only use locals if objcopy supports globalize-symbols
	355	if (!$use_locals) {
f2f8458e SR	356	return;
f2f8458e SR	357	}
8feff1ca SR	358	$convert{$ref_func} = 1;
	359	}
	360
	361	# Loop through all the mcount caller offsets and print a reference
	362	# to the caller based from the ref_func.
	363	for (my $i=0; $i <= $#offsets; $i++) {
	364	if (!$opened) {
	365	open(FILE, ">$mcount_s") \|\| die "can't create $mcount_s\n";
	366	$opened = 1;
e58918ab	367	print FILE "\t.section $mcount_section,\"a\",$section_type\n";
42e007d0	368	print FILE "\t.align $alignment\n" if (defined($alignment));
8feff1ca SR	369	}
	370	printf FILE "\t%s %s + %d\n", $type, $ref_func, $offsets[$i] - $offset;
	371	}
	372	}
	373
8da3821b SR	374	#
	375	# Step 2: find the sections and mcount call sites
	376	#
b43f7093	377	open(IN, "$objdump -hdr $inputfile\|") \|\| die "error running $objdump";
8da3821b	378
8feff1ca SR	379	my $text;
8feff1ca SR	380
b43f7093 SR	381	my $read_headers = 1;
b43f7093 SR	382
8da3821b SR	383	while (<IN>) {
	384	# is it a section?
	385	if (/$section_regex/) {
b43f7093	386	$read_headers = 0;
34698bcb SR	387
	388	# Only record text sections that we know are safe
	389	if (defined($text_sections{$1})) {
	390	$read_function = 1;
	391	} else {
	392	$read_function = 0;
	393	}
8feff1ca	394	# print out any recorded offsets
7dbdee2e	395	update_funcs() if (defined($ref_func));
8feff1ca SR	396
8feff1ca SR	397	# reset all markers and arrays
8da3821b	398	$text_found = 0;
8feff1ca SR	399	undef($ref_func);
	400	undef(@offsets);
	401
8da3821b SR	402	# section found, now is this a start of a function?
8da3821b SR	403	} elsif ($read_function && /$function_regex/) {
8da3821b	404	$text_found = 1;
8feff1ca SR	405	$text = $2;
	406
	407	# if this is either a local function or a weak function
	408	# keep looking for functions that are global that
	409	# we can use safely.
	410	if (!defined($locals{$text}) && !defined($weak{$text})) {
	411	$ref_func = $text;
	412	$read_function = 0;
bd171d5f	413	$offset = hex $1;
8feff1ca SR	414	} else {
8feff1ca SR	415	# if we already have a function, and this is weak, skip it
3f6e968e SR	416	if (!defined($ref_func) && !defined($weak{$text}) &&
	417	# PPC64 can have symbols that start with .L and
	418	# gcc considers these special. Don't use them!
	419	$text !~ /^\.L/) {
8feff1ca	420	$ref_func = $text;
bd171d5f	421	$offset = hex $1;
8feff1ca	422	}
8da3821b	423	}
b43f7093 SR	424	} elsif ($read_headers && /$mcount_section/) {
	425	#
	426	# Somehow the make process can execute this script on an
	427	# object twice. If it does, we would duplicate the mcount
	428	# section and it will cause the function tracer self test
	429	# to fail. Check if the mcount section exists, and if it does,
	430	# warn and exit.
	431	#
	432	print STDERR "ERROR: $mcount_section already in $inputfile\n" .
	433	"\tThis may be an indication that your build is corrupted.\n" .
	434	"\tDelete $inputfile and try again. If the same object file\n" .
	435	"\tstill causes an issue, then disable CONFIG_DYNAMIC_FTRACE.\n";
	436	exit(-1);
8feff1ca SR	437	}
	438
	439	# is this a call site to mcount? If so, record it to print later
	440	if ($text_found && /$mcount_regex/) {
	441	$offsets[$#offsets + 1] = hex $1;
8da3821b SR	442	}
	443	}
	444
8feff1ca	445	# dump out anymore offsets that may have been found
7dbdee2e	446	update_funcs() if (defined($ref_func));
8feff1ca	447
8da3821b SR	448	# If we did not find any mcount callers, we are done (do nothing).
	449	if (!$opened) {
	450	exit(0);
	451	}
	452
	453	close(FILE);
	454
	455	#
	456	# Step 3: Compile the file that holds the list of call sites to mcount.
	457	#
	458	`$cc -o $mcount_o -c $mcount_s`;
	459
	460	my @converts = keys %convert;
	461
	462	#
	463	# Step 4: Do we have sections that started with local functions?
	464	#
	465	if ($#converts >= 0) {
	466	my $globallist = "";
	467	my $locallist = "";
	468
	469	foreach my $con (@converts) {
	470	$globallist .= " --globalize-symbol $con";
	471	$locallist .= " --localize-symbol $con";
	472	}
	473
	474	my $globalobj = $dirname . "/.tmp_gl_" . $filename;
	475	my $globalmix = $dirname . "/.tmp_mx_" . $filename;
	476
	477	#
	478	# Step 5: set up each local function as a global
	479	#
	480	`$objcopy $globallist $inputfile $globalobj`;
	481
	482	#
	483	# Step 6: Link the global version to our list.
	484	#
	485	`$ld -r $globalobj $mcount_o -o $globalmix`;
	486
	487	#
	488	# Step 7: Convert the local functions back into local symbols
	489	#
	490	`$objcopy $locallist $globalmix $inputfile`;
	491
	492	# Remove the temp files
	493	`$rm $globalobj $globalmix`;
	494
	495	} else {
	496
	497	my $mix = $dirname . "/.tmp_mx_" . $filename;
	498
	499	#
	500	# Step 8: Link the object with our list of call sites object.
	501	#
	502	`$ld -r $inputfile $mcount_o -o $mix`;
	503
	504	#
	505	# Step 9: Move the result back to the original object.
	506	#
	507	`$mv $mix $inputfile`;
	508	}
	509
	510	# Clean up the temp files
	511	`$rm $mcount_o $mcount_s`;
512
513	exit(0);