kbuild: do not pick up CFLAGS from the environment (69ee0b35) · Commits · 戴 / test

Too many people have CFLAGS set to support building userspace. And now Kbuild picks up CFLAGS this caused troubles. Although people should realise that setting CFLAGS has a 'global' effect the impact on the kernel build is a suprise. So change kbuild to pick up value from KCFLAGS that is much less used. When kbuild pick up a value it will warn like this: Makefile:544: "WARNING: Appending $KCFLAGS (-O3) from environment to kernel $CFLAGS" Signed-off-by:

Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Bächler <thomas@archlinux.org> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com>

Makefile

+16 −3

Original line number	Diff line number	Diff line
		@@ -528,9 +528,22 @@ KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
		KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,)

		# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
		KBUILD_CPPFLAGS += $(CPPFLAGS)
		KBUILD_AFLAGS += $(AFLAGS)
		KBUILD_CFLAGS += $(CFLAGS)
		# But warn user when we do so
		warn-assign = \
		$(warning "WARNING: Appending $$K$(1) ($(K$(1))) from $(origin K$(1)) to kernel $$$(1)")

		ifneq ($(KCPPFLAGS),)
		$(call warn-assign,CPPFLAGS)
		KBUILD_CPPFLAGS += $(KCPPFLAGS)
		endif
		ifneq ($(KAFLAGS),)
		$(call warn-assign,AFLAGS)
		KBUILD_AFLAGS += $(KAFLAGS)
		endif
		ifneq ($(KCFLAGS),)
		$(call warn-assign,CFLAGS)
		KBUILD_CFLAGS += $(KCFLAGS)
		endif

		# Use --build-id when available.
		LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\

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