drivers/dio/Makefile


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#
# Makefile for the linux kernel.
#

obj-y := dio.o dio-driver.o dio-sysfs.o
#!/usr/bin/env perl
# (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 warnings;
use strict;

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

my $V = '0.1';

if ($#ARGV != 11) {
	print "usage: $P arch endian bits objdump objcopy cc ld nm rm mv is_module inputfile\n";
	print "version: $V\n";
	exit(1);
}

my ($arch, $endian, $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,
     ".init.text" => 1,
     ".ref.text" => 1,
     ".sched.text" => 1,
     ".spinlock.text" => 1,
     ".irqentry.text" => 1,
     ".softirqentry.text" => 1,
     ".kprobes.text" => 1,
     ".cpuidle.text" => 1,
     ".text.unlikely" => 1,
);

# Acceptable section-prefixes to record.
my %text_section_prefixes = (
     ".text." => 1,
);

# Note: we are nice to C-programmers here, thus we skip the '||='-idiom.
$objdump = 'objdump' if (!$objdump);
$objcopy = 'objcopy' if (!$objcopy);
$cc = 'gcc' if (!$cc);
$ld = 'ld' if (!$ld);
$nm = 'nm' if (!$nm);
$rm = 'rm' if (!$rm);
$mv = 'mv' if (!$mv);

#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 $mcount_adjust;	# Address adjustment to mcount 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 ($arch =~ /(x86(_64)?)|(i386)/) {
    if ($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]+):.*\\s(mcount|__fentry__)\$";
$section_type = '@progbits';
$mcount_adjust = 0;
$type = ".long";

if ($arch eq "x86_64") {
    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s(mcount|__fentry__)([+-]0x[0-9a-zA-Z]+)?\$";
    $type = ".quad";
    $alignment = 8;
    $mcount_adjust = -1;

    # 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;
    $mcount_adjust = -1;

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

} elsif ($arch eq "s390" && $bits == 64) {
    if ($cc =~ /-DCC_USING_HOTPATCH/) {
	$mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*c0 04 00 00 00 00\\s*brcl\\s*0,[0-9a-f]+ <([^\+]*)>\$";
	$mcount_adjust = 0;
    } else {
	$mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$";
	$mcount_adjust = -14;
    }
    $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";

} elsif ($arch eq "powerpc") {
    my $ldemulation;

    $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
    # See comment in the sparc64 section for why we use '\w'.
    $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?\\w*?)>:";
    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";

    if ($endian eq "big") {
	    $cc .= " -mbig-endian ";
	    $ld .=