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kbuild: enable 'make CPPFLAGS=...' to add additional options to CPP
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The variable CPPFLAGS is a wellknown variable and the usage by
kbuild may result in unexpected behaviour.

This patch replace use of CPPFLAGS with KBUILD_CPPFLAGS all over the
tree and enabling one to use:
make CPPFLAGS=...
to specify additional CPP commandline options.

Patch was tested on following architectures:
alpha, arm, i386, x86_64, mips, sparc, sparc64, ia64, m68k, s390

Signed-off-by: Sam Ravnborg <[email protected]>
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Sam Ravnborg committed Oct 15, 2007
1 parent 52bcc33 commit 06c5040
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Showing 9 changed files with 18 additions and 17 deletions.
2 changes: 1 addition & 1 deletion Documentation/kbuild/makefiles.txt
Original file line number Diff line number Diff line change
Expand Up @@ -1099,7 +1099,7 @@ When kbuild executes, the following steps are followed (roughly):
specified options when building the target vmlinux.lds.

When building the *.lds target, kbuild uses the variables:
CPPFLAGS : Set in top-level Makefile
KBUILD_CPPFLAGS : Set in top-level Makefile
EXTRA_CPPFLAGS : May be set in the kbuild makefile
CPPFLAGS_$(@F) : Target specific flags.
Note that the full filename is used in this
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13 changes: 7 additions & 6 deletions Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -318,7 +318,7 @@ LINUXINCLUDE := -Iinclude \
$(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) \
-include include/linux/autoconf.h

CPPFLAGS := -D__KERNEL__ $(LINUXINCLUDE)
KBUILD_CPPFLAGS := -D__KERNEL__ $(LINUXINCLUDE)

KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-fno-strict-aliasing -fno-common \
Expand All @@ -334,7 +334,7 @@ export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE
export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS

export CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE

Expand Down Expand Up @@ -523,9 +523,10 @@ KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
# disable pointer signed / unsigned warnings in gcc 4.0
KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,)

# Add user supplied AFLAGS and CFLAGS as the last assignments
KBUILD_AFLAGS += $(AFLAGS)
KBUILD_CFLAGS += $(CFLAGS)
# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
KBUILD_CPPFLAGS += $(CPPFLAGS)
KBUILD_AFLAGS += $(AFLAGS)
KBUILD_CFLAGS += $(CFLAGS)

# Use --build-id when available.
LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
Expand Down Expand Up @@ -1507,7 +1508,7 @@ quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files))


a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
$(NOSTDINC_FLAGS) $(CPPFLAGS) \
$(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
$(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)

quiet_cmd_as_o_S = AS $@
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4 changes: 2 additions & 2 deletions arch/arm/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -32,11 +32,11 @@ KBUILD_CFLAGS +=-fno-omit-frame-pointer -mapcs -mno-sched-prolog
endif

ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)
CPPFLAGS += -mbig-endian
KBUILD_CPPFLAGS += -mbig-endian
AS += -EB
LD += -EB
else
CPPFLAGS += -mlittle-endian
KBUILD_CPPFLAGS += -mlittle-endian
AS += -EL
LD += -EL
endif
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2 changes: 1 addition & 1 deletion arch/ia64/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@ cflags-y := -pipe $(EXTRA) -ffixed-r13 -mfixed-range=f12-f15,f32-f127 \
CFLAGS_KERNEL := -mconstant-gp

GAS_STATUS = $(shell $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
KBUILD_CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")

ifeq ($(GAS_STATUS),buggy)
$(error Sorry, you need a newer version of the assember, one that is built from \
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2 changes: 1 addition & 1 deletion arch/powerpc/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -75,7 +75,7 @@ CPPFLAGS-$(CONFIG_PPC32) := -Iarch/$(ARCH)
AFLAGS-$(CONFIG_PPC32) := -Iarch/$(ARCH)
CFLAGS-$(CONFIG_PPC64) := -mminimal-toc -mtraceback=none -mcall-aixdesc
CFLAGS-$(CONFIG_PPC32) := -Iarch/$(ARCH) -ffixed-r2 -mmultiple
CPPFLAGS += $(CPPFLAGS-y)
KBUILD_CPPFLAGS += $(CPPFLAGS-y)
KBUILD_AFLAGS += $(AFLAGS-y)
KBUILD_CFLAGS += -msoft-float -pipe $(CFLAGS-y)
CPP = $(CC) -E $(KBUILD_CFLAGS)
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2 changes: 1 addition & 1 deletion arch/ppc/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ endif

LDFLAGS_vmlinux := -Ttext $(KERNELLOAD) -Bstatic
# The -Iarch/$(ARCH)/include is temporary while we are merging
CPPFLAGS += -Iarch/$(ARCH) -Iarch/$(ARCH)/include
KBUILD_CPPFLAGS += -Iarch/$(ARCH) -Iarch/$(ARCH)/include
KBUILD_AFLAGS += -Iarch/$(ARCH)
KBUILD_CFLAGS += -Iarch/$(ARCH) -msoft-float -pipe \
-ffixed-r2 -mmultiple
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2 changes: 1 addition & 1 deletion arch/um/Makefile-x86_64
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ KBUILD_CFLAGS += $(_extra_flags_)
CHECKFLAGS += -m64
KBUILD_AFLAGS += -m64
LDFLAGS += -m elf_x86_64
CPPFLAGS += -m64
KBUILD_CPPFLAGS += -m64

ELF_ARCH := i386:x86-64
ELF_FORMAT := elf64-x86-64
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2 changes: 1 addition & 1 deletion drivers/atm/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ ifeq ($(CONFIG_ATM_FORE200E_PCA),y)
# guess the target endianess to choose the right PCA-200E firmware image
ifeq ($(CONFIG_ATM_FORE200E_PCA_DEFAULT_FW),y)
byteorder.h := include$(if $(patsubst $(srctree),,$(objtree)),2)/asm/byteorder.h
CONFIG_ATM_FORE200E_PCA_FW := $(obj)/pca200e$(if $(shell $(CC) $(CPPFLAGS) -E -dM $(byteorder.h) | grep ' __LITTLE_ENDIAN '),.bin,_ecd.bin2)
CONFIG_ATM_FORE200E_PCA_FW := $(obj)/pca200e$(if $(shell $(CC) $(KBUILD_CPPFLAGS) -E -dM $(byteorder.h) | grep ' __LITTLE_ENDIAN '),.bin,_ecd.bin2)
endif
endif

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6 changes: 3 additions & 3 deletions scripts/Makefile.lib
Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ modname_flags = $(if $(filter 1,$(words $(modname))),\

_c_flags = $(KBUILD_CFLAGS) $(EXTRA_CFLAGS) $(CFLAGS_$(basetarget).o)
_a_flags = $(KBUILD_AFLAGS) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
_cpp_flags = $(CPPFLAGS) $(EXTRA_CPPFLAGS) $(CPPFLAGS_$(@F))
_cpp_flags = $(KBUILD_CPPFLAGS) $(EXTRA_CPPFLAGS) $(CPPFLAGS_$(@F))

# If building the kernel in a separate objtree expand all occurrences
# of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
Expand All @@ -106,11 +106,11 @@ __a_flags = $(call flags,_a_flags)
__cpp_flags = $(call flags,_cpp_flags)
endif

c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(CPPFLAGS) \
c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
$(__c_flags) $(modkern_cflags) \
-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)

a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(CPPFLAGS) \
a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
$(__a_flags) $(modkern_aflags)

cpp_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(__cpp_flags)
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