powerpc: Add configurable -Werror for arch/powerpc

Add the option to build the code under arch/powerpc with -Werror.

The intention is to make it harder for people to inadvertantly introduce
warnings in the arch/powerpc code. It needs to be configurable so that
if a warning is introduced, people can easily work around it while it's
being fixed.

The option is a negative, ie. don't enable -Werror, so that it will be
turned on for allyes and allmodconfig builds.

The default is n, in the hope that developers will build with -Werror,
that will probably lead to some build breaks, I am prepared to be flamed.

It's not enabled for math-emu, which is a steaming pile of warnings.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index 4b2df66c79d8..459c7ee580f7 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile
@@ -2,6 +2,8 @@
 # Makefile for Kernel-based Virtual Machine module
 #
 
+subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
+
 EXTRA_CFLAGS += -Ivirt/kvm -Iarch/powerpc/kvm
 
 common-objs-y = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)