[RFC v2 8/8] docs: Kconfig/Makefile: add a check for broken ABI files

[Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>]

The files under Documentation/ABI should follow the syntax
as defined at Documentation/ABI/README.

Allow checking if they're following the syntax by running
the ABI parser script on COMPILE_TEST.

With that, when there's a problem with a file under
Documentation/ABI, it would produce a warning like:

	Warning: file ./Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats#14:
		What '/sys/bus/pci/devices/<dev>/aer_stats/aer_rootport_total_err_cor' doesn't have a description
	Warning: file ./Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats#21:
		What '/sys/bus/pci/devices/<dev>/aer_stats/aer_rootport_total_err_fatal' doesn't have a description

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
---
 Documentation/Kconfig  | 11 +++++++++++
 Documentation/Makefile |  5 +++++
 lib/Kconfig.debug      |  2 ++
 scripts/get_abi.pl     | 14 +++++++++++---
 4 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/Kconfig

diff --git a/Documentation/Kconfig b/Documentation/Kconfig
new file mode 100644
index 000000000000..a8b0701c1422
--- /dev/null
+++ b/Documentation/Kconfig
@@ -0,0 +1,11 @@
+config WARN_ABI_ERRORS
+	bool "Warn if there are errors at ABI files"
+	depends on COMPILE_TEST
+	help
+	   The files under Documentation/ABI should follow what's
+	   described at Documentation/ABI/README. Yet, as they're manually
+	   written, it would be possible that some of those files would
+	   have errors that would break them for being parsed by
+	   scripts/get_abi.pl. Add a check to verify them.
+
+	   If unsure, select 'N'.
diff --git a/Documentation/Makefile b/Documentation/Makefile
index e889e7cb8511..c6480ed22884 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -4,6 +4,11 @@
 
 subdir-y := devicetree/bindings/
 
+# Check for broken ABI files
+ifeq ($(CONFIG_WARN_ABI_ERRORS),y)
+$(shell $(srctree)/scripts/get_abi.pl validate --dir $(srctree)/Documentation/ABI)
+endif
+
 # You can set these variables from the command line.
 SPHINXBUILD   = sphinx-build
 SPHINXOPTS    =
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index cbdfae379896..b1b7e141ca99 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2110,4 +2110,6 @@ config IO_STRICT_DEVMEM
 
 source "arch/$(SRCARCH)/Kconfig.debug"
 
+source "Documentation/Kconfig"
+
 endmenu # Kernel hacking
diff --git a/scripts/get_abi.pl b/scripts/get_abi.pl
index 6a4d387ebf3b..e80f9ab2ed26 100755
--- a/scripts/get_abi.pl
+++ b/scripts/get_abi.pl
@@ -47,7 +47,15 @@ my %data;
 sub parse_error($$$$) {
 	my ($file, $ln, $msg, $data) = @_;
 
-	print STDERR "file $file#$ln: $msg at\n\t$data";
+	$data =~ s/\s+$/\n/;
+
+	print STDERR "Warning: file $file#$ln:\n\t$msg";
+
+	if ($data ne "") {
+		print STDERR ". Line\n\t\t$data";
+	} else {
+	    print STDERR "\n";
+	}
 }
 
 #
@@ -104,7 +112,7 @@ sub parse_abi {
 
 			# Invalid, but it is a common mistake
 			if ($new_tag eq "where") {
-				parse_error($file, $ln, "tag 'Where' is invalid. Should be 'What:' instead", $_);
+				parse_error($file, $ln, "tag 'Where' is invalid. Should be 'What:' instead", "");
 				$new_tag = "what";
 			}
 
@@ -205,7 +213,7 @@ sub parse_abi {
 		}
 
 		# Everything else is error
-		parse_error($file, $ln, "Unexpected line:", $_);
+		parse_error($file, $ln, "Unexpected content", $_);
 	}
 	$data{$nametag}->{description} =~ s/^\n+//;
 	close IN;
-- 
2.21.0