locking/atomics: Check generated headers are up-to-date

Now that all the generated atomic headers are in place, it would be good
to ensure that:

a) the headers are up-to-date when scripting changes.

b) developers don't directly modify the generated headers.

To ensure both of these properties, let's add a Kbuild step to check
that the generated headers are up-to-date.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com
Cc: Will Deacon <will.deacon@arm.com>
Cc: linuxdrivers@attotech.com
Cc: dvyukov@google.com
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: arnd@arndb.de
Cc: aryabinin@virtuozzo.com
Cc: glider@google.com
Link: http://lkml.kernel.org/r/20180904104830.2975-6-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Kbuild b/Kbuild
index 0053042..47c9fe1 100644
--- a/Kbuild
+++ b/Kbuild
@@ -6,7 +6,8 @@
 # 2) Generate timeconst.h
 # 3) Generate asm-offsets.h (may need bounds.h and timeconst.h)
 # 4) Check for missing system calls
-# 5) Generate constants.py (may need bounds.h)
+# 5) check atomics headers are up-to-date
+# 6) Generate constants.py (may need bounds.h)
 
 #####
 # 1) Generate bounds.h
@@ -72,7 +73,20 @@
 	$(call cmd,syscalls)
 
 #####
-# 5) Generate constants for Python GDB integration
+# 5) Check atomic headers are up-to-date
+#
+
+always += old-atomics
+targets += old-atomics
+
+quiet_cmd_atomics = CALL    $<
+      cmd_atomics = $(CONFIG_SHELL) scripts/atomic/check-atomics.sh
+
+old-atomics: scripts/atomic/check-atomics.sh FORCE
+	$(call cmd,atomics)
+
+#####
+# 6) Generate constants for Python GDB integration
 #
 
 extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py