[tip:locking/core] locking/atomics: Check generated headers are up-to-date

[tip-bot for Mark Rutland]

Commit-ID:  85f8507192fbfb4ad2ac01de879cb50045f4247f
Gitweb:     https://git.kernel.org/tip/85f8507192fbfb4ad2ac01de879cb50045f4247f
Author:     Mark Rutland <mark.rutland@xxxxxxx>
AuthorDate: Tue, 4 Sep 2018 11:48:29 +0100
Committer:  Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitDate: Thu, 1 Nov 2018 10:48:19 +0100

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.

Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: catalin.marinas@xxxxxxx
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: linuxdrivers@xxxxxxxxxxxx
Cc: dvyukov@xxxxxxxxxx
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: arnd@xxxxxxxx
Cc: aryabinin@xxxxxxxxxxxxx
Cc: glider@xxxxxxxxxx
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180904104830.2975-6-mark.rutland@xxxxxxx
---
 Kbuild                          | 18 ++++++++++++++++--
 scripts/atomic/check-atomics.sh | 19 +++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/Kbuild b/Kbuild
index 005304205482..47c9fe175bd9 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 @@ missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
 	$(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-$(CONFIG_GDB_SCRIPTS) += build_constants_py
diff --git a/scripts/atomic/check-atomics.sh b/scripts/atomic/check-atomics.sh
new file mode 100644
index 000000000000..c30101cddf2d
--- /dev/null
+++ b/scripts/atomic/check-atomics.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Check if atomic headers are up-to-date
+
+ATOMICDIR=$(dirname $0)
+ATOMICTBL=${ATOMICDIR}/atomics.tbl
+LINUXDIR=${ATOMICDIR}/../..
+
+cat <<EOF |
+gen-atomic-instrumented.sh      asm-generic/atomic-instrumented.h
+gen-atomic-long.sh              asm-generic/atomic-long.h
+gen-atomic-fallback.sh          linux/atomic-fallback.h
+EOF
+while read script header; do
+	if ! (${ATOMICDIR}/${script} ${ATOMICTBL} | diff - ${LINUXDIR}/include/${header} > /dev/null); then
+		printf "warning: include/${header} is out-of-date.\n"
+	fi
+done