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/x86/boot/Makefile b/arch/x86/boot/Makefile
index cb1035f..646292a 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -50,7 +50,7 @@
# that way we can complain to the user if the CPU is insufficient.
cflags-i386 :=
cflags-x86_64 := -m32
-CFLAGS := $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
+KBUILD_CFLAGS := $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
$(cflags-$(ARCH)) \
-Wall -Wstrict-prototypes \
-march=i386 -mregparm=3 \
@@ -61,7 +61,7 @@
$(call cc-option, -fno-unit-at-a-time)) \
$(call cc-option, -fno-stack-protector) \
$(call cc-option, -mpreferred-stack-boundary=2)
-AFLAGS := $(CFLAGS) -D__ASSEMBLY__
+AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
$(obj)/zImage: IMAGE_OFFSET := 0x1000
$(obj)/zImage: EXTRA_AFLAGS := $(SVGA_MODE) $(RAMDISK)
diff --git a/arch/x86/boot/compressed/Makefile_32 b/arch/x86/boot/compressed/Makefile_32
index 22613c6..e43ff7c 100644
--- a/arch/x86/boot/compressed/Makefile_32
+++ b/arch/x86/boot/compressed/Makefile_32
@@ -11,7 +11,7 @@
LDFLAGS_vmlinux := -T
hostprogs-y := relocs
-CFLAGS := -m32 -D__KERNEL__ $(LINUX_INCLUDE) -O2 \
+KBUILD_CFLAGS := -m32 -D__KERNEL__ $(LINUX_INCLUDE) -O2 \
-fno-strict-aliasing -fPIC \
$(call cc-option,-ffreestanding) \
$(call cc-option,-fno-stack-protector)
diff --git a/arch/x86/boot/compressed/Makefile_64 b/arch/x86/boot/compressed/Makefile_64
index dc6b3380..3013ad0 100644
--- a/arch/x86/boot/compressed/Makefile_64
+++ b/arch/x86/boot/compressed/Makefile_64
@@ -6,11 +6,11 @@
targets := vmlinux vmlinux.bin vmlinux.bin.gz head_64.o misc_64.o piggy.o
-CFLAGS := -m64 -D__KERNEL__ $(LINUXINCLUDE) -O2 \
+KBUILD_CFLAGS := -m64 -D__KERNEL__ $(LINUXINCLUDE) -O2 \
-fno-strict-aliasing -fPIC -mcmodel=small \
$(call cc-option, -ffreestanding) \
$(call cc-option, -fno-stack-protector)
-AFLAGS := $(CFLAGS) -D__ASSEMBLY__
+AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
LDFLAGS := -m elf_x86_64
LDFLAGS_vmlinux := -T