[RFC PATCH 1/5] Add generation of Module.symb in streamline_config

[Cristina Moraru <cristina.moraru09@gmail.com>]

Add generation of ./scripts/Module.ksymb file containing
associations of driver file names and corresponding CONFIG_*
symbol:

foo_KCONF=CONFIG_FOO

This file will be further loaded by the Makefile as a
configuration file: all foo_KCONF will be considered variables
and all CONFIG_FOO will be their associate values. The suffix
is added to be able to differentiate the new variables from
all existing variables in the Makefile system. Each kernel
module will receive its CONFIG_FOO option as macro in the
compilation command (-D parameter) and will expose it along
with other module attributes (attributes of struct module).

Note: this patch is built on the assumption that each driver
has exactly one associate CONFIG_FOO symbol. CONFIG_* options
that are required by CONFIG_FOO are not included. They can be
found by SAT resolvers.

This patch is part of a research project within
Google Summer of Code of porting 'make localmodconfig'
for backported drivers. The goal is to enable each
module to expose in /sys its corresponding CONFIG_* option.
The value of this attribute will be dynamically pegged by
modpost without requiring extra work from the driver developers.
Further, this information will be used by a hardware interogation
tool to extract build information about the existing devices.

Signed-off-by: Cristina Moraru <cristina.moraru09@gmail.com>
---
 scripts/kconfig/streamline_config.pl | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/scripts/kconfig/streamline_config.pl b/scripts/kconfig/streamline_config.pl
index b8c7b29..686d02a 100755
--- a/scripts/kconfig/streamline_config.pl
+++ b/scripts/kconfig/streamline_config.pl
@@ -128,9 +128,11 @@ my @config_file = read_config;
 # Parse options
 my $localmodconfig = 0;
 my $localyesconfig = 0;
+my $genmoduleksymb = 0;
 
 GetOptions("localmodconfig" => \$localmodconfig,
-	   "localyesconfig" => \$localyesconfig);
+	   "localyesconfig" => \$localyesconfig,
+	   "genmoduleksymb" => \$genmoduleksymb);
 
 # Get the build source and top level Kconfig file (passed in)
 my $ksource = ($ARGV[0] ? $ARGV[0] : '.');
@@ -147,6 +149,7 @@ my %objects;
 my $var;
 my $iflevel = 0;
 my @ifdeps;
+my @drv_objs;
 
 # prevent recursion
 my %read_kconfigs;
@@ -348,6 +351,31 @@ foreach my $makefile (@makefiles) {
     close($infile);
 }
 
+foreach my $obj_key ( keys %objects )
+{
+	my @config_options = @{$objects{$obj_key}};
+	# Last index of array is 0 is equivalent to array's size is 1
+	if ( $#config_options == 0) {
+		push(@drv_objs, $obj_key);
+	}
+}
+
+sub gen_module_kconfigs {
+	my $module_ksymb = $ENV{'srctree'}."/scripts/Module.ksymb";
+
+	open(my $ksymbfile, '>', $module_ksymb) || die "Can not open $module_ksymb for writing";
+
+	foreach (@drv_objs) {
+		print $ksymbfile "$_" . "_KCONF=" . "@{$objects{$_}}\n";
+	}
+	close($ksymbfile);
+}
+
+if ($genmoduleksymb) {
+	gen_module_kconfigs();
+	exit(0);
+}
+
 my %modules;
 my $linfile;
 
-- 
2.7.4