kbuild: enable 'make CFLAGS=...' to add additional options to CC
The variable CFLAGS is a wellknown variable and the usage by
kbuild may result in unexpected behaviour.
On top of that several people over time has asked for a way to
pass in additional flags to gcc.
This patch replace use of CFLAGS with KBUILD_CFLAGS all over the
tree and enabling one to use:
make CFLAGS=...
to specify additional gcc commandline options.
One usecase is when trying to find gcc bugs but other
use cases has been requested too.
Patch was tested on following architectures:
alpha, arm, i386, x86_64, mips, sparc, sparc64, ia64, m68k
Test was simple to do a defconfig build, apply the patch and check
that nothing got rebuild.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 643839a..5130984 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -77,8 +77,8 @@
CFLAGS-$(CONFIG_PPC32) := -Iarch/$(ARCH) -ffixed-r2 -mmultiple
CPPFLAGS += $(CPPFLAGS-y)
AFLAGS += $(AFLAGS-y)
-CFLAGS += -msoft-float -pipe $(CFLAGS-y)
-CPP = $(CC) -E $(CFLAGS)
+KBUILD_CFLAGS += -msoft-float -pipe $(CFLAGS-y)
+CPP = $(CC) -E $(KBUILD_CFLAGS)
CHECKFLAGS += -m$(CONFIG_WORD_SIZE) -D__powerpc__ -D__powerpc$(CONFIG_WORD_SIZE)__
@@ -88,35 +88,35 @@
ifeq ($(CONFIG_POWER4_ONLY),y)
ifeq ($(CONFIG_ALTIVEC),y)
ifeq ($(GCC_BROKEN_VEC),y)
- CFLAGS += $(call cc-option,-mcpu=970)
+ KBUILD_CFLAGS += $(call cc-option,-mcpu=970)
else
- CFLAGS += $(call cc-option,-mcpu=power4)
+ KBUILD_CFLAGS += $(call cc-option,-mcpu=power4)
endif
else
- CFLAGS += $(call cc-option,-mcpu=power4)
+ KBUILD_CFLAGS += $(call cc-option,-mcpu=power4)
endif
else
- CFLAGS += $(call cc-option,-mtune=power4)
+ KBUILD_CFLAGS += $(call cc-option,-mtune=power4)
endif
endif
ifeq ($(CONFIG_TUNE_CELL),y)
- CFLAGS += $(call cc-option,-mtune=cell)
+ KBUILD_CFLAGS += $(call cc-option,-mtune=cell)
endif
# No AltiVec instruction when building kernel
-CFLAGS += $(call cc-option,-mno-altivec)
+KBUILD_CFLAGS += $(call cc-option,-mno-altivec)
# Enable unit-at-a-time mode when possible. It shrinks the
# kernel considerably.
-CFLAGS += $(call cc-option,-funit-at-a-time)
+KBUILD_CFLAGS += $(call cc-option,-funit-at-a-time)
# Never use string load/store instructions as they are
# often slow when they are implemented at all
-CFLAGS += -mno-string
+KBUILD_CFLAGS += -mno-string
ifeq ($(CONFIG_6xx),y)
-CFLAGS += -mcpu=powerpc
+KBUILD_CFLAGS += -mcpu=powerpc
endif
cpu-as-$(CONFIG_4xx) += -Wa,-m405
@@ -126,7 +126,7 @@
cpu-as-$(CONFIG_E200) += -Wa,-me200
AFLAGS += $(cpu-as-y)
-CFLAGS += $(cpu-as-y)
+KBUILD_CFLAGS += $(cpu-as-y)
head-y := arch/powerpc/kernel/head_$(CONFIG_WORD_SIZE).o
head-$(CONFIG_8xx) := arch/powerpc/kernel/head_8xx.o